BOC: Micro

All of the following fungi are appropriately listed with their respective morphology, EXCEPT:

Aspergillus sp. produce ascospores produce chains of conidia on the end of phialides Pseudallescheria boydii produces ascospores Syncephalastrum sp. produce merosporangia: daisy petals Fusarium sp. produce macroconidia: canoe shaped, microconidia (chinese letter) Coccidioides immitis produces arthroconidia

The set of tubes in the image to the right are the Hugh and Leifson Oxidative/Fermentative (O/F) basal medium with glucose and a pH indicator of bromthymol blue. This image demonstrates a reaction of: (both blue)

Glucose non-oxidizer no reaction OF: pos is yellow

Each of the following organisms may possess extended-spectrum beta-lactamase (ESBL) activity except:

Pseudomonas aeruginosa esistant to ampicillin, cefazolin, and other first and second generations cephalosporins Escherichia coli, Klebsiella oxytoca, Proteus mirabilis: ability to inactivate penicillins, extended-spectrum cephalosporins, and aztreonam

Which of the following is the most common method for diagnosing malaria?

Demonstration of the organism in peripheral blood needs thick/thin smears, giemsa stain biochemical: bacteria nor sporozoa

Which of the following viruses requires a complex lymphoblastoid cell culture, and is rarely, if ever, diagnosed by culture?

Epstein-Barr Virus heterophile antibody test and serology Herpes Simplex Virus: shell vial assay and modified cell lines Cytomegalovirus: CA-NAAT

Which of the following organisms is Gram-positive?

Erysipelothrix Pasteurella: small, GN bacillus with bipolar staining. Aeromonas: GN bacillus. Fusobacterium: GN bacilli with tapered or pointed ends.

A gram-positive bacillus that has a rod-coccus cycle (short, thin rods in young cultures and cocci in older cultures) and an odor resembling cheese is:

Brevibacterium spp. habitat in milk and milk products yellow bacteremia indwelling catheters in immunocomp Rothia spp.: pleomorphic, coccoid and bacillary, rare, endocarditis, bone white to grey, spoke wheel, GP bacilli, diphtheroidal, esculin Dermabacter hominis: short GP rods, immunocomp

Chocolate agar is recommended for the detection of Haemophilus species as it contains the following:

Hemin and NAD NADase: SBA, destroys NAD Lactose: MAC and HE, GN bacilli Whole blood: CNA, blood agar

The Knott technique serves as a means of identifying:

Loa loa RBC lysed bodies killed and straightened centrifuged and spread on slide nematode, flies, chrysops in rain forests african eye worm, deerfly (mango fly) uninterrupted column of nuclei extending into the tip of the tail Calabar swelling

Which phase of the bacterial growth curve demonstrates the greatest growth activity?

Log phase Lag phase: not started growing yet Stationary phase: cells die and get produced evenly Death phase: cells die fast

Beyond direct detection, what molecular method listed below is being widely used in clinical laboratories across the United States and allows for rapid detection of a bacteria from an isolated colony?

MALDI-TOF Matrix assisted laser desorption time of flight, colony isolated, metal target, matrix applied, proteins cocrystillize, transfer protons to colony mix, vaporizes proteins, proteins seperated based on mass to charge ratio, mass spectrum Next generation sequencing: high throughput and accuracy for microorganisms, expensive, time consuming Pyrosequencing: identify microorganisms and antimicrobial resistance genes, expensive, time consuming

What is the first step of the ethyl acetate concentration procedure?

Mix fresh stool specimen with 10% formalin and strain to obtain a sediment 2. Add normal saline, centrifuge, and decant the supernatant fluid 3. Resuspend the sediment with 10% formalin and add ethyl acetate 4. Centrifuge specimen to obtain four layers

Which Mycobacterium species will have a negative result for niacin, nitrate reduction, Tween hydrolysis (5 days), and iron uptake?

Mycobacterium bovis

A three-year-old female was seen by a local ear, nose and throat specialist for chronic ear pain. She had been treated several times for otitis media by her pediatrician with no resolution. Drainage from her ear grew an acid fast bacillus that gave the following biochemical reactions: Iron Uptake- Positive Nitrate reduction- Positive Arylsulfatase - Positive MacConkey agar growth, 5 days- Positive

Mycobacterium fortuitum skin and soft tissue; abscesses Mycobacterium avium complex: lung disease, slow growing, heat stable cat pos, T2H pos Mycobacterium chelonae: otis media, MAC pos, arysulfatase pos Mycobacterium kansasii: lung infections, slow growing, nitrate pos, tween 80 pos, cat pos

A tech is working with a small, Gram-negative coccobacillus that may be Brucella spp. Which of the following tests could the tech use to rule out this organism?

Urease negative

dark, elliptical conidia in branching chains with the conidia separated by a delicate black scar or disjunctor

cladosporium this branching gives rise to chains of blastoconidia w/ septate hyphae Rhinocladiella: picket fence arrangement Acrotheca: similar to cladosporium but short, hooks on a hat rack Phialophora: short, vase- or flask-like phialides, spherical or slightly elliptical conidia are produced in clusters

The infective stage for the majority of all intestinal amebae is the:

cyst nonfeeding and environmentally resistant troph: motile feeding, binary fission, not infective

A methicillin-resistant Staphylococcus aureus was recovered from a wound infection. Which antibiotic would be used for treatment?

Vancomycin Cefoxitin tests for MRSA mecA gene for MRSA

All of the following agents can be handled using biosafety level 2 practices, EXCEPT:

Marburg virus requires biological safety level 4 high risk of life-threatening diseases transmitted via aerosols filoviruses hemorrhagic fever MRSA, Herpes simplex virus, and Candida albicans: biosafety 2, germ tubes, spikes on side

All of the following Mycobaterium species produce pigments, EXCEPT?

Mycobacterium fortuitum group commonly isolated in the environment Mycobacterium scrofulaceum: yellow colonies in dark / light, scotochromogen, cervical lymphadenitis in children Mycobacterium marinum: pigmented in light (photochromogens), normal flora to fish, commonly causes skin infection, open wounds in salt water Mycobacterium kansasii: pigmented in light (photochromogens), isolated in NTM lung disease, skin and soft tissue infections, immunocomp pts, neg niacin and iron uptake, pos nitrate reduction and Tween hydrolysis (5 days), yellow after light

3 day old colony incubated at 30o C. border to border white hair-like mycelium with peripheral borders of brown and brown-black pigmentation. consistent with one of the Zygomycetes. high power photomicrograph is a lactophenol blue stained mount of a fruiting head in which a non-septate hypha terminates in a bulbous columella (arrow) that extends into a spherical sporangiophore. Rhizoids were not observed.

Mucor spp. dark outer pigment, production of pigmented hyphal segments or sporangia, no rhizoids, terminal end of a sporangiophore, distinctive bulbous columella, smooth walled, tiny brown pigmented Circinella: distinctive backward curve leading to globose sporangia at tips, brown staining, darkened pigment in the colony surface mycelium Rhizopus spp: root like rhizoids, distinctive "nodal" placement, sporangiophore is straight at the tip, saclike sporangium enclosing sporangiospores, Zygomyces, brown, tissue infection Syncephalastrum spp.: spherical sporangium, tip of narrow stacks of sporangiphore, cylindrical elongated merosporangia, daisy petal, mistaken for aspergillus Lichtheimia spp: broad, ribbon-like hyphae, sporangiophores smooth, rhizoids internodal Syncephalastrum spp: Narrow sporangiophores, daisy petal

What is the identifying characteristic of Aureobasidium pullulans?

The production of a black yeast-like colony plant debris, soil, wood and the indoor air environment 7 day maturity Bipolaris spp.: production of polar germ tubes, germ tubes extend from both sides of the conidium and run parallel to the long axis of the conidium, incubated in water at 25C for up to 24 hours Phialophora spp.: Urn-shaped phialides, distinct cup or flask shaped collerate Alternaria spp.: drum stick-shaped multi-celled, muriform macroconidia called dictyospores

What is the most helpful feature in differentiating the Zygomycetes from the other hyaline molds in the clinical mycology laboratory?

The production of spores within sporangia Rhizopus and Absidia species produce rhizoids

A physician suspected that a young, sexually active woman had bacterial vaginosis. Which of the following specimen sources is the correct specimen of choice to support a bacterial vaginosis infection?

Vaginal Gardnerella vaginalis: foul, smelling discharge Urethral: Neisseria gonorrhoeae and Trichomonas vaginalis Endocervical and cervical: Trichomonas, gonococci, herpes, mycoplasma, and chlamydia

Which of the following organisms is Gram-negative?

Vibrio ox pos, water, cholera, wound infections Bacillus: GP, foodborne gastroenteritis, anthracis Staphylococcus: GPC, grape like clusters, skin, UTI, wound, toxic shock Nocardia: GP, skin, lymphocutaneous, pulmonary

When vitreous fluid is collected, it must be transported to the laboratory within 15 minutes and set up immediately for culture. This specimen type must be handled with care as this specimen type is not easy to obtain. What body site is this specimen collected from?

eye needle aspiration sterile, screw-cap tube lungs: thoracentesis CNS: CSF, spinal shunt or spinal tap heart: pericardial fluid

The most significant class of microbial targets for Natural Killer (NK) cells is:

viruses bacteria: phagocytosis, PMN, monos, macrophages Parasites: eosinophils

Current CDC (2014) recommendations for initial HIV screening include FDA-approved immunoassay for detection of:

HIV-1 and HIV-2 antibody, HIV-1 p24 antigen 5th generation assay western blot: HIV Abs (p24, p31, gp41, and gp 120/160)

A tech is working with a small Gram-negative coccobacillus that may be Francisella tularensis. Which of the following tests could the tech use to rule out this organism?

Catalase negative

Which of the following bioterrorism agent categories is the easiest to spread, has the ability to cause major harm, panic, and death, and carries the highest level of risk with regard to national security?

Category A highest priority B: second highest, moderately easy to disseminate, moderate morbidity and low mortality, specific enhancements of CDC diagnostic capacity and enhanced disease surveillance C: 3rd highest, emerging pathogens, engineered for a mass spread

If a Mycobacterium sp. infection is suspected on a bone marrow or body fluid, what stain should be used to detect these bacteria?

Acid fast stain Ziehl-Neelsen or Kinyoun heat and/or the acid allow the stain to penetrate the cell walls Wright: most heme exams New methylene blue: vital stain, see ribosomes in reticulocytes Hematoxylin and eosin stain: BM exam

The organism depicted in the image to the right is found as normal flora of the mouth, GI, and genital tracts; it is known to cause a chronic disease that exhibits abscesses, tissue fibrosis, and draining sinuses. What is the name of this chronic disease?

Actinomycosis non spore bacilli CNS, face, neck, molar tooth, small, white and slightly wrinkled, slender, GP rods, diphtheroidal Sporotrichosis: nodular lymphangitis, Sporothrix spp, GP rods Borreliosis: no branching, GP rods, spirochete

What is the phenotypic property of Saccharomyces yeast species that helps establish its species identification?

Ascospore production rapid growing Torulopsis (Candida) glabrata: glucose and trehalose Cryptococcus spp: polysaccharide capsule

All of the following are Lancefield carbohydrate antigens found on beta-hemolytic Streptococcus species. All of the following antigens are found on organisms from the Streptococcus anginosus group EXCEPT?

B Streptococcus agalactiae A: Streptococcus pyogenes, also Streptococcus anginosus F: Streptococcus anginosus, also Streptococcus constellatus G: Streptococcus anginosus (small), also Streptococcus dysgalactiae (large)

Which of the following parasites has a life cycle that most closely resembles that of Plasmodium species?

Babesia microti infects RBC febrile illness ticks vs mosquitoes Wright or Giesma small, delicate, pleomorphic ring-form trophozoites prominent chromatin dot single, double or the classic tetrad (Maltese cross)

A laboratory recently purchased a continuous monitoring system for blood culture analysis. The system is able to detect CO2 production by growing organisms and as a result will produce a color change in the sensor located at the bottom of the blood culture bottle. The instrument will detect this color change and alert the staff that a blood culture is positive for bacterial growth. Which of the following instruments uses this methodology?

BacT/ALERT BACTEC: fluorescence, CO2 diffuse into water w/ sensor, H+ ions = (-) pH Versa TREK System: agitation, magnetic stirrer, enhance oxygenation MALDI-TOF: mass spectrometry

All of the following organisms are aerobic organisms, EXCEPT?

Bacteroides fragilis anaerobic gram-negative rod inhibit phagocytosis Francisella tularensis: aerobic gram-negative coccobacillary, requiring cystine or cysteine, tularemia Pseudomonas aeruginosa: aerobic gram-negative motile bacillus, wound infections in moist air, immunocomp Neisseria meningitidis: aerobic, gram-negative, cocci-shaped, most common, pair/tetrads, (A, B, C, H, I, K, L, W135, X, Y, Z, 29E - Z')

Which ciliated intestinal parasite is pathogenic for humans?

Balantidium coli fecal-oral route; pigs Giardia duodenalis: traveler's diarrhea / beaver fever, intestinal protozoan, water, duodenal secretions

Which of the culture media listed is selective for the isolation of Yersinia enterocolitica in stool samples?

Cefsulodin-Irgasan-Novobiocin (CIN) inhibits enteric bacteria in stool, clear colonies, red bulls eye center (mannitol fermentation), neutral red pH Cycloserine Cefoxitin Fructose Agar (CCFA): clostridioides difficile, stool, intestinal bacterial flora MacConkey Sorbitol Agar: screen e coli, slow, nonfermentation, colorless, sorbitol for lactose Bordet-Gengou Blood Agar: bordetella spp, contains penicillin, methicillin, or cephalexin

Which of the following is the bacterial agent associated with antibiotic-associated pseudomembranous colitis?

Clostridioides difficile Campylobacter jejuni: bloody diarrhea with white blood cells, consumption of infected food Shigella dysenteriae: dysentery with white blood cells, contaminated water Bacillus cereus: watery diarrhea with white blood cells and vomiting, consumption of a pre-formed toxin, food (meats, vegetables, and rice)

Illustrated in this photograph is the surface of a MacConkey agar plate growing colonies of a non-fermentative Gram negative bacillus recovered from a wound specimen. The iridescent light pink colonies suggest Acinetobacter species. Each of the following characteristics are helpful in supporting this identification EXCEPT:

Denitrification of nitrates do not denitrify nitrogen Use to ID pseudomonas spp all are nonmotile, beta lact (penicillin) (R) Acinetobacter baumannii are glucose ox Acinetobacter lwoffi are non glucose ox

The laboratory test most commonly used to establish a definitive diagnosis of primary syphilis is:

Direct fluorescent antibody test Treponema pallidum FTA with adsorption: late latent or tertiary syphilis

An occupation or avocation that should be avoided to prevent infection with Francisella tularensis is:

Hunting and skinning small game

A 20-year-old female was admitted into the hospital complaining of 10 to 15 bloody mucous stools per day, fever, gastrointestinal disturbances, abdominal pain, and nausea. The preliminary O & P report went out as "Probable Entamoeba histolytica trophozoites and cysts, confirmation pending." What is this patient most likely suffering from?

Intestinal amebiasis Abdominal cramps, Fever, Diarrhea Vomiting, Abdominal tenderness, Fatigue, Excessive gas, Rectal pain while having a bowel movement, Unintentional weight loss, bloody stools

Which of the following organisms has been isolated from nasal secretions and causes atrophic rhinitis, a tissue-destructive disorder in the nose?

Klebsiella pneumoniae subsp. ozaenae Cronobacter sakazakii: neonatal meningitis Yersinia pseudotuberculosis: mesenteric adenitis in children - acute appendicitis Morganella morganii: UTI, alkaline urine and ammonium phosphate crystalluria

Pictured are tiny, gray-white, non-hemolytic colonies growing on blood agar that are non-descript. The Gram stain reveals elongated, rectangular gram-positive bacilli in short chains. Key to the identification would be the lack of biochemical activity. This bacterium is usually recovered as a genital tract commensal, but has also been found to provide protection against other infective bacteria. With these observations, what is the most likely identification of the isolate?

Lactobacillus species mouth, gastrointestinal tract, and female genital tract light alpha Bacillus cereus: large, flat, gray-yellow, granular, beta, GP rod

A joint fluid was received in the microbiology laboratory. The specimen was cloudy and many neutrophils with intracellular and extracellular Gram negative diplococci were seen on the Gram stain. The specimen was inoculated to sheep blood and chocolate agar and grew a small, grayish white colony on chocolate with no growth observed on the sheep blood. Which of the following is most likely the organism?

Neisseria gonorrhoeae Haemophilus influenzae: Gram negative coccobacilli, bacteremia, x and v factors, can grow with Staphylococcus aureus Haemophilus ducreyi: x factor Bacteroides fragilis: anaerobic Gram negative rod / coccobacilli Streptococcus pyogenes: Gram positive cocci in chains, SBA, choc

Which of the following choices represents the characteristic indicator, fermentable sugar(s), and bacteriostatic agent(s) that are present in MacConkey agar respectively?

Neutral red/lactose/bile salts and crystal violet XLD: Phenol red/lactose, sucrose, and xylose/sodium desoxycholate and bile salts EMB: Eosin Y and methylene blue/lactose and sucrose/Eosin Y and methylene blue HE: Bromothymol blue/lactose, salicin, and sucrose/bile salts

The 10-day-old colonies grown on SABHI agar incubated at 30° C as illustrated in the top photograph are characteristic of those recovered from skin nodules of workers living in South America, especially Brazil. Although a dimorphic fungus might be suspected from the appearance of the slow-growing, gray white, cob-web like colonies, the final identification can be confirmed by observing the microscopic appearance of tease mounts prepared from the surface mycelium, as observed the bottom photograph. Based on these descriptions, what is the most likely identification? (lollipop)

Paracoccidioides brasiliensis lollipop similar to blastocyces Sporothrix schenckii: rapid, dark in mature, Small smooth, oval, daisy like Coccidioides immitis: black, barrel shape Histoplasma capsulatum: cobweb like, circular, roughened, spike- like

Matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) is used for identification of aerobic bacterial isolates on a urine culture bench. Upon placing the target into the MALDI-TOF instrument, no peaks were found on one of the patient samples (out of 20 patients). The quality control passed. What caused this issue?

Patient sample was not added to the well

Which of the following parasites has the longest undulating membrane?

Pentatrichomonas hominis

The saying, "If it wasn't recorded, it never happened," holds true in the microbiology laboratory because accrediting agencies require that detailed and accurate records be maintained. All of the following are purposes of record retention within the microbiology laboratory EXCEPT?

Records are not important as computers store all the data Records provide a paper or electronic audit trail Records serve as a point of reference Records assist in identifying trends

A tech receives a request for VRE colonization testing on a patient in the hospital. Which of the following is an appropriate area of the body for culture for screening?

Rectal area Nares and groin: staph aureus

Adult forms of the following worms are all hermaphroditic, EXCEPT:

Schistosoma blood fluke Hymenolepis spp. and Taenia spp.: cestodes Clonorchis spp.: trematodes

In the upper bi-plate image are shown colonies growing on MacConkey (left), and on blood agar (right). Relatively large confluent gray-white colonies are observed growing on blood agar, while smaller smooth convex colonies with a deep red pigmentation are growing on MacConkey agar. Note that the pigment is confined to the colonies growing on MacConkey agar that does not diffuse into the adjacent agar. In follow-up to making a presumptive identification, observe that the colonies growing on the DNase agar in the lower image (right) show a positive reaction with clearing of the adjacent agar, compared to the growth of a negative control growing in the streak lines to the left. From these observations, select from the multiple choices the presumptive identification of this isolate.

Serratia marcescens red on MAC show lactose fermentation, but ruled out b/c doesnt extend into adjacent agar positive reaction on DNase pos ornithine decarboxylase, citrate, Voges Proskauer, and the hydrolysis of gelatin Proteus vulgaris, Providencia stuartii, and Citrobacter koseri ruled out b/c don't produce DNase

The photograph on the right is of a 5% sheep blood agar plate inoculated with a throat culture. It is common practice to stab the agar with the inoculating needle, as seen at the tip of the arrow, in order to detect or accentuate the reaction of:

Streptolysin O Streptococcus pyogenes

Which Aspergillus species, when cultured, will have colonies that resemble powdered cinnamon?

Aspergillus terreus Aspergillus flavus: yellow-green Aspergillus fumigatus: blue-green to gray-green Aspergillus niger: black

The subsurface umbrella-shaped zone of motility seen in this SIM tube (arrow) is characteristic of Listeria monocytogenes. The optimum temperature of incubation to best illustrate this property is:

25C flagella are inactive at temperatures above 30°C

Which of the following characteristics will produce the most desirable smear to be examined using a Gram stain?

A thin monolayer of material from an abscess on a slide CSF smears: best prepared w/ cytocentrifugation EDTA tubes: not appropriate for bacterial cultures

Which one of the following organisms is sensitive to bacitracin:

Group A Streptococcus Group D Streptococcus: bile esculin Staphylococci: wound and skin infection, cat

Which culture medium is specifically formulated to recover Salmonella typhi from stool specimens?

Bismuth sulfite agar Selenite broth: e coli SS: salmonella and shigella Deoxycholate citrate agar: Salmonella paratyphi

suspicious form in a red cell (lacking Schüffner dots) is responsible for which of the following conditions?

Black water fever ring form of Plasmodium falciparum Wuchereria bancrofti: filarial worms that infect humans, bancroftian filariasis, elephantiasis, sheathed, lymphatic tissues, no nuclei in tail Trypanosoma cruzi: chagas disease, trypomastigotes and amastigotes in human, epimastigotes in bug C or U shape, no troph

Dematiaceous molds can be broadly separated into two major groups; the agents of chromomycosis and clinically insignificant commensals or contaminants. Which of the statements below is true?

Agents of chromomycosis grow more slowly than clinically insignificant commensals or contaminants. >7 days

Bacterial colonies often emit distinct odors associated with foods. Which organism produces an odor that resembles fresh apples?

Alcaligenes faecalis (odorans) Pseudomonas aeruginosa: beta, SBA, metallic sheen, grape like odor Streptococcus milleri: butterscotch odor CDC group EF4: popcorn smell

This suspicious form, that measures 25 µm, was recovered in an eye sample. It is associated with which of the following diseases?

Amebic keratitis Acanthamoeba spp, invade CNS, granulomatous amebic encephalitis (GAE), subacute or chronic, trauma or an underlying disease, nausea, vomiting, stiff neck, dizziness, headaches and seizures African eye worm infection: filarial nematode, loa loa, circulates in the blood, lives in subcutaneous tissue, subconjunctiva of the eye

Which of the following organisms would give the gram stain microscopic results seen in this image? (GP bacilli, spores in bacilli - very large, square ends in chains)

Bacillus anthracis Corynebacterium diphtheriae: gram-positive bacillus, pleomorphic, club, parallel rows, v or l formation, no spores, irregular, palisades, diphtheria, ID by confirming presence of diptheria toxin, nasopharynx

Of the Gram-negative bacilli listed below, which is motile with polar tufts of flagella and can produce yellow pigment?

Burkholderia cepacia non-wrinkled yellow pigment

A 68-year-old female, who recently vacationed in Brazil, presented to her physician exhibiting overall weakness, fever, and enlarged lymph nodes. Blood was collected for culture and parasitic examination. The culture was negative. This suspicious form was recovered upon examining the Giemsa-stained preparation. This patient is most likely suffering from what condition/disease?

Chagas disease trypomastigote zoonosis throughout american continent, reduvidd bugs acute, indeterminate, and chronic pathogenic tsetse fly for African trypanosomiasis (sleeping sickness) - Trypanosoma brucei rhodesiense (east) and Trypanosoma brucei gambiense (west), central belt of africa

Illustrated in this high-power microscopic view is a large spherical ovum measuring 130 µm that was found in a stool specimen. These ova often have brown staining that suggests passage through a biliary duct on its way to the large intestine. Based on the appearance of this ovum, select the correct presumptive identification.

Fasciola hepatica large, oval, thin, smooth shell, flat non shouldered operculum, no clear space Clonorchis sinensis: Chinese liver fluke, freshwater snail as host, small, shouldered opercula, small knob, brown bile stained, hepatic duct system, sedimentation method / wet mount, free swimming, straight, non-forked tail, feces

Each of the following characteristics will differentiate between Listeria monocytogenes and Erysipelothrix rhusiopathiae except:

Fermentation of glucose Listeria monocytogenes: motile at RT, umbrella shaped motility, hydrolyzes esculin, and is catalase positive, H2S neg, small, gray to yellow-white, narrow beta, chinese letter, GP bacillus, straight, single / pairs, short chains, tumbling motility Erysipelothrix rhusiopathiae: non motile, does not hydrolyze esculin, and is catalase-negative, H2S pos, long and thin, short chains, v shape, no spores, fish, light gray, slender, GP bacilli, bottle brush, test tube brush Streptococcus bovis: esculin

Trichomonas, Giardia, and Chilomastix belong to the following parasitic group based on the type of motility:

Flagellates amoebae: parasitic, e histolytica, e coli Ciliates: parasitic, b coli microsporidia: non motile protozoa, Cryptosporidium spp., Cystoisospora belli

A microbiologist was surprised when he could not recover Helicobacter pylori from gastric biopsies in which organisms were seen in the tissue sections. He was advised to switch from the Campy BAP selective medium to Skirrow's blood agar because the latter is:

Free of cephalothin Helicobacter pylori is highly susceptible to cephalothin, can grown in sheep/horse blood

In tissues infected with Histoplasma capsulatum, which of the following is usually true?

Fungus is usually intracellular Mucorales: Hyphae usually invade blood vessels Cryptococcus neoformans: Encapsulated yeast cells are typical, India Ink stain, in CSF Cryptosporidium spp.: sporozoa, oocyst, water/food

This rapidly growing hyaline fungus is the most common cause of Keratomycosis (an infectious disease of the cornea). The colonies can range in color from rose to mauve to orange. This organism is commonly recovered from blood and grows on sabourauds dextrose agar with brain heart infusion. The microscopic appearance shows abundant banana or canoe shaped macroconidia. What fungus causes this disease?

Fusarium species small clusters or clustered together - sporodochia multicelled macroconidia Beauveria: insect pathogen, abundant, single celled tear shaped sympodulconidia on sympodulae Chrysosporium: wide-based, single-celled conidia, on nonspecialized cells Geotrichum: abundant arthroconida

A male urethral specimen was sent to the laboratory for a gonococcal culture and Gram stain. The specimen was received on a calcium alginate swab and cultured to chocolate and Thayer-Martin agars. A Gram stain was performed and presented intracellular and extracellular Gram negative diplococci. After 24, 48, and 72 hours of 37°C incubation in CO2, no growth was seen on either chocolate or Thayer-Martin agars. Which of the following is the most probable cause for lack of Neisseria gonorrhoeae growth?

Inappropriate swab was used for collection calcium alginate swabs toxic to this charcoal treated cotton or rayon swab should be used - absorb out toxic material grows best on chocolate, Thayer-Martin, or Martin-Lewis agar incubated at 37°C, between 24-72 hours, in 3-7% CO2 cold sensitive and affected by delay in culturing

The beta hemolysis seen around the opaque, flat, spreading colonies illustrated in this photograph of a 5% blood agar plate is helpful in differentiating Bacillus cereus (hemolytic) from Bacillus anthracis (not hemolytic). Each of the following characteristics is also helpful in differentiating these two species EXCEPT:

Lecithinase production B. cereus, B. anthracis, and B. mycoides produce lecithinase Bacillus cereus: motile, hydrolyzes gelatin, and produces acid from salicin Bacillus anthracis: neg for motile, gelatin, and salicin, soil / herbs

Which of the following life cycle stages is correctly matched to its location within the host?

Merozoites in erythrocytes Sporozoites and Merozoites (in liver cells) Trophozoites, Schizont, Merozoites, Gametocytes (in erythrocytes)

An 18-year-old woman woke up in the morning to find that her left knee was hot, swollen, and very painful. She could not walk to work and a friend offered her a ride to the clinic. She had never had a swollen joint before. Physical exam revealed a tender knee joint which yielded purulent synovial fluid on aspiration. Gram-negative intracellular diplococci were seen on the Gram stain. She also had a cervical discharge that was cultured. The cause of her infection would grow best on:

Modified Thayer Martin (MTM) agar at 35º C with CO2 bacterial arthritis staph aureus - septic arthritis (70%) <30 years: Neisseria gonorrhoeae LIM (Todd Hewitt broth with antibiotics): strep agalactiae blood agar at 42° C and incubating in microaerophilic conditions: campylobacter V factor (NAD): haemophilus spp

Each of the following tests is helpful in the species identification of Staphylococcus aureus EXCEPT:

Modified dimethyl sulfoxide (DMSO) test make the bacterial cell-permeable to the diffusion of the oxidase reagent micrococcus Thermostable endonuclease, Deoxyribonuclease, and Tube coagulase test

Why is Mycobacterium tuberculosis not seen on gram stained smears?

Mycobacterium tuberculosis has a waxy coating on its surface which prevents gram stain penetration. acid fast stain required (detergent / heat used) pos niacin and nitrate reduction pos Tween hydrolysis (5 days) and iron uptake >10days rough, non-pigmented or buff colony positive nitrate If color w/ mycobacteria on gram stain, considered a beaded GP rod (uneven staining) Mycobacteria are comparable in size to other bacterial bacilli Nucleocapsids are not found in bacteria

What is the main problem with the acridine orange stain?

Once a bacterium is detected, a Gram stain must be used to determine differential staining characteristics. distinguishing between bacteria and debris reagents not highly toxic detect both living and dead bacteria

This suspicious form was recovered from a nodule biopsy. It measures 300 µm in length and lacks a sheath

Onchocerca volvulus Trypanosoma trypomastigote: blood, lymphatic fluid, or CSF

The following is the BEST test to differentiate between Aeromonas hydrophila and Escherichia coli from a wound culture:

Oxidase production A. hydrophila is oxidase positive E.coli is oxidase negative both are GN bacilli, glucose pos, ferment lactose, pink on MAC Gram stain: differentiate shape and arrangement ability to ferment glucose: differentiate Enterobacteriaceae from non-fermenting ability to ferment lactose: on MAC, and ID GN bacilli

The following are all possible causes of cell death in HIV infections, EXCEPT?

Penetration of the membrane by the HIV spike protein spikes are scattered surface of particle, helps virus attach to host, do not penetrate or cause death Depletion of cellular components, cytoplasmic leakage, and depletion of T-lymphocytes will all cause cell death

MacConkey agar contains all of the following except:

Penicillin Bile salts Lactose: pink Crystal violet selective and differential Enterobacteriaceae GN bacilli

Host cells (e.g., white blood cells, epithelial cells) will appear what color on a properly stained Gram stain?

Pink if violet: under de colorized

Which Plasmodium species tends to infect any red blood cell, regardless of the age of the cell?

Plasmodium falciparum

Wright-stained peripheral blood smear is a developing intra-erythrocyte schizont

Plasmodium vivax benign tertian malaria, Schüffner dots, schizont developing, normal erythrocyte size and pigmentation, single ring, enlarged, pale staining Plasmodium spp.: relapsing fever Plasmodium falciparum: schizonts rare in PB, malarial forms are early ring forms, crescent / banana shaped gametocyts Plasmodium malariae: schizonts no more than 12, rosette, erythrocytes not enlarges and normal pigmentation, no schuffner's dots, quartan, sporozoite, salvary glands Plasmodium ovale: schizonts fill entire cell, malarial pigment, scattered schuffner's dots, 8 segments, ring form enlarged oval, normochromic

A tech working in microbiology has reported the following results throughout their workday. Which of the result would be considered an urgent alert value that must be called to the physician?

Positive acid fast smear maybe M tuberculosis close contact and droplets Staph aureus, e coli, or GPC not urgent

The tech is working in microbiology and typically, there is an automatic call list generated by the laboratory information system (LIS) for urgent microbiology alerts. The LIS is currently down for maintenance so the tech has to manually pull a list of urgent reports. Which of the following should the tech considered an urgent result?

Positive blood culture showing Gram positive cocci Sepsis can have a mortality rate of 40% Urine cultures with >100,000 cfu/mL of E. coli: UTI Wound cultures with Staphylococcus epidermidis: normal skin flora Sputum cultures with Streptococcus pneumoniae: indicate pt has pneumonia

Rothia mucilaginosus is a member of the family Micrococcaceae that has been associated with endocarditis in patients after cardiac catheterization, as well as intravenous drug users. Which test listed below would be most helpful in making a species identification?

Presence of a capsule mucoid No growth 5% NaCl slow catalase

This Gram-positive coccus is catalase positive. The tests shown are a tube coagulase test inoculated with the isolate, and an MRSA screen plate containing 4% NaCl and 6 µg/mL of oxacillin. A 0.5 McFarland standardized inoculum of the isolate is inoculated to the plate. What step should you take next?

Report the isolate as methicillin-resistant Staphylococcus aureus. is coag pos (plasma clotted) demonstrating resistance to oxacillin, methicillin, and nafcillin (grew on MRSA plate)

The blue color seen in the Simmon's citrate agar slant to the right tube shown in this photograph, indicating a positive reaction, results from:

Production of ammonia from ammonium phosphate contains inorganic sodium citrate (carbon) and ammonium phosphate (buffer and nitrogen) Bacterial species that can extract carbon from the sodium citrate can also extract nitrogen from the ammonium phosphate = release of ammonia and rise in pH bromthymol indicator from green to blue

Illustrated in this photomicrograph of a gastric biopsy specimen are a few thin, curved and S-shaped bacteria (arrows). This picture is suspicious for Helicobacter pylori. An additional test helpful in confirming this identification is:

Rapid urease maintain residence in the highly acid gastric mucosa, basis for the CLO test (rapid conversion of urea after inoculation, bright pink/red) Indoxyl acetate and hippurate hydrolysis neg growth at 37° C

Which virus is the MOST common etiological agent of viral respiratory diseases in infants and children?

Respiratory syncytial virus lungs and breathing passages croup, bronchiolitis, and interstitial pneumonia Coxsackievirus A: enterovirus, fever, aseptic meningitis, sepsis-like illness, pneumonia, lymphoid Epstein-Barr virus: mono, sore throat, fever, and general malaise, Burkitt lymphoma, hepatitis, and Reye syndrome

The amplification of an RNA target through Reverse transcription PCR (RT-PCR) to detect HIV requires the following enzyme for the initial synthesis of DNA from the viral RNA template:

Reverse transcriptase synthesize DNA from an RNA viral template Transcriptase: synthesize RNA from DNA viral template Taq polymerase: primer extension thermocycler: instrument, alters temp, denaturing

The light pink-yellow, mucoid, non-hemolytic colonies on blood agar, an uncommon isolate, belongs to the aerobic actinomycetes. This species is widely spread among farm animals and may cause human respiratory infections upon animal contact. The Gram stain reveals Gram positive cocci, with younger colonies also showing branching bacilli, with residuals seen here. Carbohydrates were not utilized (asaccharolytic), and the decarboxylase reactions are also negative. The presumptive identification is:

Rhodococcus equi: smooth, mucoid or rough yellow to pink-red GPC Nocardia asteroides: velvety to chalky, wrinkled, brown yellow, GP bacilli, thin, branched and filamentous, urease, immunocomp, pulmonary or wound infections, IV / shunts Streptomyces spp: smooth, granular, powdery or floccose, Light yellow brown, Long, slender branching, GP bacilli, soil, upper respiratory and skin infections, gardening or farming

A patient is showing signs of an intravenous catheter-associated infection. The physician has removed the catheter and sent the catheter tip along with a skin swab of the catheter site to the laboratory for testing. The physician ordered a Gram stain of the skin entry site and a culture of the catheter tip. On which of the following media should the catheter tip be plated?

Sheep Blood Agar and Thioglycollate Broth SBA supports all pathogens from catheter (staph aureus and coag neg staph are most common), thio broth is an enriched medium, anaerobes, aerobes, facultative GN Broth and Sheep Blood Agar: gastrointestinal pathogens from stool specimens vs recovery of Salmonella and Shigella species Thayer Martin and LIM Broth: recovery of Neisseria gonorrhoeae and Neisseria meningitidis vs recovery of Streptococcus agalactiae Sheep Blood Agar and Bismuth Sulfite Broth: bis - recovery of Salmonella typhi

The appearance of the bacterial colonies growing on the surface of the Hektoen Enteric (HE) agar plate shown in the photograph to the right are consistent with all of the following bacterial species EXCEPT:

Shigella sonnei non lactose produce translucent green non pigmented on HE yellow colonies on HE agar - lactose; thymol blue indicator shigella: diarrheal disease, blood and pus Klebsiella oxytoca: respiratory or urinary tract, hospital Enterobacter sakasakii: lower respiratory tract infections, wound infections, and UTI Serratia marscens: respiratory or urinary tract, maybe gastrointestinal tract, hospital

A tech is reviewing a Gram stain from a positive blood culture bottle. The background on the stain shows pink debris and the tech thinks that there is also Gram-negative bacilli but is having difficulty differentiating the artifact and possible organisms. What could the tech do next to help determine if bacteria are present in the blood culture bottle?

Stain with Acridine Orange fluorescent stain fluids with low bacterial numbers (CSF) differentiate bacteria from debris detect both living and dead bacteria Wright-Giemsa stain: direct blood smears, detection of malaria Calcofluor White: dye, detect yeast cells and hyphae, skin and mucous membrane scrapings Periodic Acid-Schiff: identify fungal elements

An infective agent of skin wound infections and an agent of toxic shock syndrome, the large, entire, golden-yellow, smooth convex colonies on blood agar were recovered from a swab specimen after 48 hours incubation at 37o C. In the image to the right, clusters of gram-positive cocci were observed microscopically in a gram stain prepared from one of the colonies. The coagulase reaction was positive. With these observations, select the name of this isolate from the choices given.

Staphylococcus aureus 6.5% NaCl exfoliative toxin Micrococcus luteus: smooth, pigmented, deep golden yellow, GPC, tetrads, coag neg, (S) bacitracin; a disk, (R) fuaxolidone, clinically insignificant Rothia mucilaginosis: clear, light pink-gray, mucoid, GPC, pairs, short, chains, oral cavity, dental plaque

The observation of darkly pigmented colonies on agar as illustrated in this photograph is somewhat of a surprise. The colonies of each of the following bacterial species may have an appearance similar to that seen here, EXCEPT:

Stenotrophomonas maltophilia Prevotella melaninogenica: protoporphyrin - dark pigment Chromobacterium violaceum: violacein - violet pigment - dark Pseudomonas aeruginosa: yellow-green or yellow-brown pigment called pyoverdin, pyocyanin blue, pyomelanin (brown or black), not part of enterobacteriaceae, common cause UTI, catheterized pts, green colonies, grape like or similar to corn tortilla chip odor

A catalase-negative, a-hemolytic, gram-positive diplococci was isolated from a sputum specimen. The image shown here demonstrates a zone of growth inhibition around the "P disk," indicating optochin susceptibility. What is the identification of this isolate?

Streptococcus pneumoniae virulence factor: capsule Streptococcus agalactiae: group b, beta heme, arrowhead shaped zone, CAMP, neonatal meningitis, bacitracin (R) Streptococcus pyogenes: group a, beta heme, acute pharyngitis, bacitracin (S), a disk, PYR, streptolysin O, M protein

The following parasite is transmitted through the ingestion of contaminated pork:

Taenia solium tapeworm, intestinal infection, maybe cysticercosis (encysting of the larvae in the tissue, CNS) proglottids are longer than wide less than 13 lateral uterine branches Taenia saginata: beef tapeworm, proglottids are longer than wide, more than 13 lateral uterine branches Echinococcus granulosum: canine, oncosphere hatch in the intestinal tract, migrate through circulatory system to tissue Hymenolepsis nana: dwarf tapeworm, ingestion of the egg, in intestinal tract, weight loss, nausea, weakness, and diarrhea

An expectorated sputum specimen is received for culture at your laboratory. You are preparing to make slides and inoculate the media and are observing the gross appearance of the specimen. The specimen is a mixture of watery, bloody, and purulent material. Which area(s) of the specimen is most likely indicated for culture and slides?

The bloody and purulent areas of the specimen are most indicated for culture and slide preparation.

Which of the following helminths is a tissue nematode whose life cycle resides in a single host?

Trichinella spiralis nematode - roundworm contaminated pork Taenia solium (pork tapeworm), Taenia saginata (beef tapeworm), and Diphyllobothrium latum (fish tapeworm) are all cestodes (tape worms)

Which animal was involved in the reassortment of influenza A viruses that led to the 2009 novel influenza A H1N1 virus?

pigs Cows, deer, and horses: 2009 H1N1 virus

Which of the following amoebae has a flagellate form as part of its life cycle?

Naegleria fowleri form when in distilled water or deprived of nutrients Trichomonas tenax: has flagellate form, not amoebae Pneumocystis jirovecii: no flagellate, fungus Acanthamoeba spp: no flagellate, typical amoebic trophozoites

The historical medium of choice for isolation of Francisella is:

Cysteine blood glucose agar Chocolate agar and Modified Thayer-Martin agar: able to support francisella

Which of the following HPV types are most likely to be associated with cervical cancer?

16 and 18

Micro: Which of the following organisms is best visualized by use of a darkfield microscope?

Borrelia -Spirochetes best in darkfield microscopy -relapsing fever Poxviridae -largest / most common -oval or brick-shaped -light micro Entamoeba: regular bright field Streptococcus -round or oval-shaped -GPC -chains -bright field

All of the following are commercial methodologies that Chlamydia and Neisseria identification have been based on, EXCEPT?

Branched chain DNA technology for HIV, HBV, HCV viral load assays viruses target probes to preamplifier probes and target nucleic acids probes bind to label probes w/ alkaline phosphatase Ligase chain reaction (uses thermostable ligase binding probes together ), hybrid capture (uses RNA probes attaching to DNA, fixed to solid capture ab, substrate added), and strand displacement amplification (isothermal nucleic acid amplification technique): commercial assays

Micro: Large, one-celled, smooth-to-tuberculate macroconidia, and smooth or echinulate microconidia are typical of mycelial phase growth of which organism?

Histoplasma capsulatum -dimorphic fungus -histoplasmosis, a lung disease -grow in soil and material contaminated with bat or bird droppings -grows in the lungs as a yeast -within mononuclear cells as small, round, to oval yeast cells -invades the reticuloendothelial system -lymph nodes, liver, spleen, and the bone marrow Blastomyces dermatitidis -blastomycosis -mycelial phase -septate, delicate hyphae -single, pyriform conidia on short to long conidiophores -lollipops Coccidioides immitis -mycelial phase -small, septate hyphae with right angle branching -racquet -develop into rectangular or barrel-shaped arthroconidia -stain darkly with lactophenol cotton blue Paracoccidioides brasiliensis -septate hyphae with small pyriform or globose conidia -found on the sides of the hyphae

In multi-drug resistant tuberculosis (MDR-TB), which drugs normally used in first-line treatment of TB are ineffective?

Isoniazid and rifampin second-line drugs include aminoglycosides and fluoroquinolones

A respiratory culture is submitted to the microbiology laboratory for testing. An organism displaying the following characteristics is recovered: Gram stain shows fat, Gram-negative rods in single or short chains that may demonstrate bipolar staining Faster growth at 25° C Gray-white, translucent colonies on sheep blood agar (SBA) at 24 hours that turn slightly yellow and opaque at 48 hours Irregular colonies that have a "fried egg" and/or "hammered copper" appearance after 48-72 hours Catalase positive Oxidase negative Urea negative Indole negative

Yersinia pestis sent to LRN reference lab automated systems should be avoided - misidentify, create aerosols

Illustrated in the image to the left are 3-day old colonies growing on blood agar. The colonies are gray and spreading, and a sweet, fruity odor is noted. Plump, Gram-negative coccobacilli are seen on Gram stain. This isolate belongs to the motile, non-fermenters with peritrichous flagella. Carbohydrate utilization is asaccharolytic. Nitrite reduction produces gas and citrate is positive. From the multiple choices, select the name of this isolate.

Alcaligenes faecalis ox pos, urease neg, soil and water, opportunistic, contact with moist items, contaminated nebulizers, respirators and lavage fluids Bordetella bronchiseptica: small, non-hemolytic, smooth, mercury droplet, translucent and non-pigmented, small Gram-negative coccobacilli, motility pos, peritrichous flagella, Nitrates are not reduced, rapid production of urea, 4 hrs Moraxella catarrhalis: small, pinpoint, 24 hrs, nonpigmented, Small, Gram-negative coccobacilli in pairs and short chains, non motile, no acid so carbohydrates (asaccharolytic), nitrates reduced, urease neg, SBA Acinetobacter baumannii: large, white, entire, convex and opaque, Gram-negative coccobacilli, also could be diplococci / GP, glucose and lactose pos on OF, ox neg, nitrates not reduced

What is the infective stage for the intestinal amebae?

Cyst non-feeding stage thick protective cell wall Trophozoite: feeding form, fragile (gastric juices) Larvae: immature, (nematodes, filariae, cestodes, and trematodes) Egg: in worms (nematodes, cestodes, and trematodes)

Direct detection methods are available for Bordetella pertussis from nasopharyngeal specimens; however, caution should be used when collecting the specimen because inhibition can occur based on the type of swab that is used. Which of the following swabs have an inhibitory effect on PCR testing for Bordetella pertussis?

Calcium-alginate swabs on wire shaft inhibit the polymerase enzyme used in PCR cotton swabs have inhibitory effects on specimen growth Rayon swabs on plastic shaft, Dacron swabs on plastic shaft, and flocked swabs on plastic shaft: all can be used in PCR

A small, microaerophilic, curved, gram-negative rod which was isolated from a diarrhea stool specimen gave the following results: Grew best at 42 ºC Oxidase positive Resistant to cephalosporin Susceptible to nalidixic acid Hippurate hydrolysis positive What is the MOST probable identification of this organism?

Campylobacter jejuni

The growth of yellow-white yeast colonies with a smooth or hair-like surface within 2 - 3 days on non-selective culture media generally requires further procedures to make a presumptive identification. Microscopic observation of the subculture of colonies growing on cornmeal agar is one such approach, as illustrated in the photomicrograph. Note the "logs in stream" arrangement of elongated blastoconidia. From the multiple choices, select the name of the presumptive yeast identification.

Candida kefyr loose-like clusters, indicates a contaminant, received broad-spectrum antibiotics, immune-suppressed, isolated from blood, respiratory secretions, skin and urine Canidida glabrata: uniform, small, spherical cells, tight clusters, glucose and trehalose, UTI, slow growing, smooth Candida parapsilosis: delicate radiating conidiophores, tiny conidia, "sagebrush" or "cross matchstick", grey-white, hair like Candida krusei: short branches, elongated cells in a treelike or crossed matchstick Candida tropicalis: smooth, gray-white, germ tubes

All of the following Candida species can be commonly recovered in a clinical specimen of blood, EXCEPT?

Candida neoformans CSF: Candida neoformans, Candida albicans, Candida tropicalis, & Candida parapsilosis

The red/pink color of the colonies seen on this MacConkey agar plate is an indication of:

Lactose-fermenting gram-negative bacilli selective and differential color b/c neutral red indicator detecting a lower pH due to acid production

Illustrated in the upper left image in the composite photograph are 5-day old gray-white colonies growing on 7H10 agar. The acid-fast stain shown at the lower left reveals short, thick, acid-fast bacilli with filamentous forms. The micro-colony as microscopically observed on Lowenstein Jensen medium as illustrated in the photomicrograph at the upper right. A positive iron assimilation test is shown in the lower right image by the appearance of black pigment on a colony growing on a Lowenstein Jensen slant following an additional 2 days incubation where drops of ferric ammonium citrate had been added to the growing colony. With these observations, select from the multiple choices the identification of the Mycobacterium species presented in this exercise.

Mycobacterium fortuitum smooth, gray-white waxy Acid-fast staining short and filamentous bacilli filamentous slender, branching bacilli iron from ferric ammonium sulfate nosocomial infections skin trauma/scratches contaminated water skin and soft tissue infections non- pigmented 3-5 days neg niacin nonpath Mycobacterium chelonae: rapid, <5 days, slender and non-distinctive, spherical, granular and opaque, antimicrobial (R), skin infections, indwelling catheters Mycobacterium gordonae (intraventricular shunts, neg niacin and nitrate reduction, pos Tween hydrolysis (5 days), slow growing, smooth, tap water bacillus) and Mycobacterium scrofulaceum (young children): >10 days, scotochromogens, yellow, narrow, red staining

The body of an adult tapeworm is known as the:

Strobila made up of segments known as proglottids Proglottid: chain of egg-producing units Scolex: specialized structure for attachment, anterior end Rostellum: helps attach to intestines, smooth or with hooks

Contact with infected cat feces is responsible for the transmission of:

Toxoplasma gondii Blastocystis hominis: amoeba, fecal oral route, contaminated food, drink or fomites, diarrhea

Molecular methods can identify the presence of methicillin resistant staphylococcus aureus (MRSA) in patient specimens by detecting different species-specific genes. All of the following are species-specific genes in detecting MRSA EXCEPT?

van A detect vancomycin resistant isolates - VRE 16S and 23S ribosomal RNA genes and spacer regions, DNA gyrase (gyrA), and Superoxide dismutase (sodA) also elongation factor (tuf), glyceraldehyde-3-phosphate dehydrogenase gene (gap), and heat shock protein (HSP60/GroE)

Aspergillus, fusarium, penicillium, or Syncephalastrum

Aspergillus species irregular chains of conidia from phialides, cleistothecium, telomorphic, Conidiophores with metulae and phialides are typical Fusarium spp: opportunistic, keratitis, banana shaped macroconidia Penicillium spp: rarely cause infection, sinusitis, keratitis, chains of conidia on phialides from metulae Syncephalastrum spp: rarely cause infection

Illustrated in the top image is a 3.5-day-old brown/black, smooth yeast colony that is usually considered a contaminant when recovered in laboratory cultures. Reports of verrucose skin and visceral infections with this black yeast have been reported. The bottom image illustrates the microscopic view as prepared in a mount prepared from the surface of the colony. Note the background dark-staining hyphae from which are produced small, elliptical conidia. Select from the choices below the correct presumptive identification of this isolate.

Aureobasidium pullulans rapidly-growing not species specific Exophiala jeanselmei: yeast like, later velvety yellow brown to black mold, darkly pigmented hyphae, loose clusters of dark-staining elliptical conidia, distinctive long narrow conidiophores with a sharply pointed tip Phaeoannellomyces werneckii: black yeasts, elongated yeast cells, daughter cell extended from mother cell to form a scar (annelide)

Micro: Bacillus anthracis, Yersinia pestis, Francisella tularensis, Brucella species

Bacillus anthracis -large, GP rod -square ends -single and short chains -aerobic spore-forming Yersinia pestis -fat, GN rod -single or short chains -bipolar staining Francisella tularensis -very tiny, weakly stained GN coccobacilli Brucella spp. -very small, GN coccobacilli -may stain GP -urease pos -slow growth -ox pos -cat pos -motility neg -nitrate pos -use rabbits, rodents, squirrels and other small mammals as reservoirs -infected through bites of infected deer flies, ticks and spiders

Group A beta-hemolytic streptococci are best characterized by which of the following:

Bacitracin sensitivity CAMP test: group B strep, production of a diffusible, extracellular protein, enhances hemolysis of sba by staph aureus Optochin sensitivity: strep pneumoniae (S) vs alpha hemolytic strep (R) hydrolysis of bile esculin: enterococci vs strep

Micro: Which of the following is a selective media recommended for the isolation of Clostridioides difficile?

Cefoxitin-cycloserine-fructose agar (CCFA) -differential/selective agar -stool samples -yellow colonies -"ground glass" appearance BCYE -enrichment agar -contains yeast extract -Legionella species -Francisella and Nocardia species LKV -selective anaerobic agar -Bacteroides and Prevotella spp TCBS -selective and differential -Vibrio species -inhibit GP organisms -high pH -if ferment sucrose: turn bromthymol blue indicator to yellow

aily activities by microbiology personnel should be performed to ensure patients receive the best care. All of the following activities should be performed daily EXCEPT?

Check to ensure autoverification of results is working correctly Daily: Compare Gram stain reports with what grows in culture to ensure all organisms are recovered Check antimicrobial susceptibility reports to ensure correct drug/bug profiles Check susceptibility reports for multiple-drug-resistant organisms

The serum medium and methylene blue stain originally described by Loeffler are both helpful in the identification of:

Corynebacterium diphtheriae B pertussis; potato starch and glycerol in media, not metachromatic Streptobacillus moniliformis: serum supplements needed in media, do not stain metachromatic Gardnerella vaginalis: human blood required in media

Which of the following molds is classified as a zygomycete?

Cunninghamella species rapid grower, soil, opportunistic, immunocomp, profuce gray to white, aerial mycelium, hyaline, sparsely septate Microsporum nanum, Trichophyton schoenleinii, and Epidermophyton floccosum: dermatophytes

Illustrated in the photomicrograph is a small 8 µm ameboid-like oval trophozoite with a pair of nuclei each with prominent karyosomes. This trophozoite was observed in a stool specimen of a person with intermittent persistent diarrhea, loss of appetite and flatulence. What is the presumptive identification of this organism?

Dientamoeba fragilis 2 nuclei, prominent karysome (appear fragmented into four or more), cytoplasm fine granular, rapid degeneration, troph, intestinal Antigen immunoassays and sequence analyses Giardia lamblia: 2 nuclei, each with outer membrane with a central karyosome and on either side, 4 flagella, falling leaf motility Cystoisospora belli: modified acid-fast stain, oocyst, faint outline of dark red, coccidian intestinal opportunistic

A 54-year-old male from Finland presented to the local clinic with abdominal pain, weight loss, weakness, and digestive discomfort. Patient history revealed the man's diet was rich in raw fish. A complete blood count (CBC) was performed and revealed macrocytic anemia. A stool for parasitic examination was also ordered. Initial examination of the stool specimen revealed this suspicious form measuring 70 µm by 48 µm. This patient is most likely infected with:

Diphyllobothrium latum freshwater broad fish tapeworm crustaceans and freshwater fish eggs in wet prep of fresh stool eggs are ovoid, operculated, terminal knob, yellow brown proglottids broader than long Fasciolopsis bruski: intestinal trematode, snail as host, ingestion of raw or undercooked water plants, eggs large, oval, elongated, transparent, yellow-brown, free swimming, straight non-forked tail, bile ducts, feces

Following a diagnosis of tuberculosis, this physician moved to the Adirondack Mountains where he experienced an improvement in his health. He then opened a medical practice in Saranac Lake and founded the Adirondack Cottage Sanatorium where the standard of care for tuberculosis involved prolonged bed rest. Who is this physician?

Edward L. Trudeau American physician promote the therapy and cure of tuberculosis William Henry Welch: Professor of Pathology and Dean of Medicine at Johns Hopkins, discovery and characterization of Clostridium perfringens, "Welch bacillus", gas gangrene Hermann Biggs: director of the New York City Department of Health, control tuberculosis in New York City Theobald Smith: professor of Pathology at Harvard University, program for the vaccination of cattle against bovine tuberculosis, Babesia parasite, Texas cattle fever

Observed in a stool specimen passed from a person with minor intestinal symptoms is an 8 µm in diameter cyst as shown in the photomicrograph. Note the four nuclei and their distinctive blotlike karyosomes. Based on the microscopic appearance of this cyst, select from the list of answer choices the presumptive identification.

Endolimax nana small cysts, four nuclei, minute central karyosome w/ clear space, ball in socket, cytoplasm smaller vacuoles, non path amoeba, large karysome, no peripheral chromatin large bowel

iodine-stained cyst, measuring 20 µm in diameter, that was found in a stool specimen from a patient with persistent or intermittent diarrhea and fever. Which of the following organisms is depicted in the image?

Entamoeba histolytica moderately large less common than Entamoaba coli up to 4 nuclei centrally placed karyosome distinctive thin rim of chromatin colitis and hepatic abscesses erode the intestinal wall and travel to the liver fecal excretions Entamoeba coli: larger, more than 4 nuclei, irregular spaced, large eccentric karyosome, irregular distribution of chromatin around outer rim Entamoeba hartmanni: small, nuclei similar to e histolytica and either side of chromatoidal bar and rounded ends, ova, 4 nuclei, central karysome, blotchy chromatin ring, small chromatin bar with rounded edges, nonpath, intestinal, cyst, water / food

Micro: Illustrated in the photograph is a bile esculin agar plate inoculated with a bacterial isolate from a urinary tract infection. The most likely identification is:

Enterococcus faecalis Esculin 6.5% NaCl Enterococcus species -hydrolyzes esculin -grows in the presence of bile Stenotrophomonas maltophilia -hydrolyzes esculin -doesn't grow in the presence of bile -not appear on bile esculin medium -bluish on MAC Streptococcus mutans -viridans streptococci -does not grow on bile esculin agar -does not hydrolyze esculin

The media on the left with the red pigmentation on MacConkey agar indicates lactose fermentation. Note the sorbitol MacConkey agar plate on the right, which are growing non-pigmented, gray-white colonies. The isolate presented in this exercise is representative of the bacterial species that have been recovered from stool specimens in several outbreaks of patients with diarrhea following ingestion of contaminated ground beef. Which of the following is the identification of this isolate?

Enterohemorhragic E.coli (EHEC) produces shiga toxin, non-bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome Shigella dysenteriae: non-lactose fermenter, no pigmented colonies on macconkey, sorbitol neg, produce shiga toxin Klebsiella aerogenes: lactose fermenter, production of sorbitol, pigmented colonies on sorbitol MacConkey agar

Which Enterobacteriaceae is the most common cause of uncomplicated urinary tract infections (UTIs)?

Escherichia coli Proteus mirabilis and Klebsiella oxytoca: enterobacteriaceae, pretty common

All of the following statements concerning biochemical reactions are true, EXCEPT: Tube A: dark blue Tube B: pink Tube C: brown Tube D: clear

Escherichia coli Tube A: sodium citrate utilization positive (e coli) Tube B: urea hydrolysis positive (Bordetella bronchiseptica) Tube C: esculin hydrolysis positive (Enterococcus faecalis) Tube D: phenylalanine deaminase positive (Morganella morganii)

All of the associations listed below between bacteria and their expected colony morphology on 5% sheep blood agar are correct, EXCEPT:

Escherichia coli - pink colonies, GN bacillus, beta lactose fermenter, sorbitol pos, 5% SBA (grey colonies), MAC (pink) colonies, pos sodium citrate Pseudomonas stutzeri: dry, wrinkled, gray-yellow colonies on blood agar. Chryseobacterium (Flavobacterium) meningosepticum: smooth and yellow colonies

Which of the following specimen processing techniques is based on the principle that parasites are heavier than sample debris and will be present in the sediment after being processed?

Ethyl acetate concentration parasites float Cellophane tape preparations and the entero-test: debris-removal

To accurately identify aerobic actinomycetes to the species level, the use of molecular methods, such 16S rRNA, can be used. However, there are limitations in identifying Nocardia and other aerobic actinomycetes by molecular methods. All of the following are limitations, EXCEPT?

Extracting DNA some aerobic actinomycetes can be difficult to lyse - lysozyme resistance and production of extracellular polysaccharides Technology and expertise: not approved Information from databases: inaccurate information being reported High quality sequence data: minimum of 500 base pair

Illustrated in the top image is a slow-growing, 8-day-old colony with velvety brown, deep radial grooves and a black periphery consistent with one of the agents of chromomycosis. In the bottom image, note the conidiophores produced from the sides of the hyphae producing short, branching phialides, giving rise to clusters of elliptical conidia. From the list of choices shown below, select the correct presumptive identification of this isolate.

Fonsecaea pedrosoi acrotheca-type sporulation Phialophora verrucosa: slow-growing, nondistinctive olive brown to gray-black mycelium, elongated narrow bottle-like phialides with collarettes, loose clusters of conidia Cladophialophora carrionii: slow growing, smooth mold, olive-gray surface mycelium, distinctive cladosporium sporulation, black pigmentation on reverse, non specific, long unbranched chains of elliptical conidia, each pair separated by a scar-like dysjunctor Exophiala spp.: slow growing, more flat and velvety, long and narrow phialides end, distinctive sharply pointed terminal end, clusters of elongated pigmented conidia are produced

The adult worms of which of the following parasites resides in the human intestine?

Heterophyes heterophyes abdominal pain and discomfort, chronic mucous diarrhea, eosinophilia, undercooked fish, proper fecal disposal Paragonimus westermani: cough, fever, chest pain, blood tinged sputum, cerebral problems Clonorchis sinensis: fever, abdominal pain, diarrhea, anorexia, epigastric discomfort, and occasional jaundice, enlargement of liver, leukocytosis, and eosinophilia Schistosoma haematobium: abdominal pain, fever, weight loss, cough, bloody diarrhea, eosinophilia, Painful urination, hematuria, Katayama fever

A 7-year-old male presented to the clinic with mild, abdominal pain, diarrhea, and nausea. Patient history revealed that the child lives in a rat and insect infected shack where sanitation practices were poor. A stool sample was collected and submitted for an ova and parasites examination. Numerous suspicious forms were seen in the stool concentrate that measured 60 µm by 75 µm. This child is MOST likely infected with:

Hymenolepis diminuta lacks polar filaments Hymenolepis nana: Light infection, asymptomatic, but many cause abdominal pain, diarrhea, irritability, and headache Echinococcus granulosus: eggs rare, hydatid cyst in tissue Dipylidium caninum: eggs in groups, egg packlets, small, proglottids are longer than wide, pair of genital pores

Each of the following laboratory characteristics can be used to separate Bacteroides fragilis from the closely related Prevotella/Porphyromonas group of anaerobes EXCEPT:

Indole production Bacteroides fragilis: grow in 20% bile, bile (R), no brick red fluorescence under UV, bile esculin anaerobe Prevotella: no growth 20% bile, no esculin, brick red fluorescence under UV

A 27-year-old female graduate student recently returned from South America, where she completed a nature study of the rainforest. She spent months "living off the land." The woman went to her physician seeking treatment for a sinus infection, which she thought was responsible for several recent bouts of diarrhea. Upon questioning the patient, the doctor decided to collect stool for culture and parasitic examination. The stool culture was reported as "no enteric pathogens isolated." This suspicious form was seen on both wet preparations and on a permanent stain. It measures 17 µm. The identity of this form is most likely:

Iodamoeba butschlii single nucleus, large karysome, nuclear membrane, no peripheral chromatin, cytoplasm vacuolated, ball in socket, large vacuole

A tech is working on a wound culture and identifies Staphylococcus aureus in the culture. When inputting the data into the patient report in the LIS, the tech accidentally enters Staphylococcus epidermidis instead. How should the tech handle correcting this report?

Issue a corrected report which incidates both the initial incorrect report and the correct report

The small beta hemolytic bacterial colonies growing on blood agar as shown in the upper photograph were recovered from an induced sputum specimen from a young child with pneumonia. The colonies were slow growing, small, entire and show soft beta hemolysis. Plump, Gram-negative coccobacilli, lying singly, in pairs and short chains, are seen on gram stain as illustrated in the lower photomicrograph. Most strains are chemically non-reactive except for a positive oxidase reaction and acid produced from dextrose and maltose. What is the name of the isolate?

Kingella kingae normal flora in the upper respiratory tract Children sometimes agent of pneumonia colonies pin point, narrow zones of soft beta short, plump, gram-negative coccobacilli in pairs and short chains positive oxidase selective carbohydrate utilization of dextrose and maltose Capnocytophaga spp.: grow poorly on SBA, indistinct, small, circular and smooth, no beta hemolysis, Long, slender, fusiform gram-negative bacilli, neg indole and pos carb for fructose, lactose, galactose, dextrose and maltose, skin abscess at the site of a dog bite or blood cultures Cardiobacterium hominis: small and non-hemolytic on SBA, cocco-bacilli, rosette-like clusters, pos indole, acid produced from carb like dextrose and maltose Eikenella corrodens: large, blood and choc, non hemolytic on blood, larger on choc and pitting of colonies, slender, gram negative bacilli with rounded ends, carb neg (asaccharolytic) like dextrose and maltose, reduction of nitrates (pos), ox neg

The cryptococcal antigen test used to diagnosis Cryptococcus neoformans meningitis is based on what type of rapid methodology?

Latex agglutination beads coated with cryptococcal antibodies specific CSF and blood Immunodiffusion: days, dimorphic infections Hemagglutination: RBC instead of beads, viruses Complement fixation: determine antibody presence for a specific organism or virus, days

Which parasite corresponds with the sandfly as its insect vector?

Leishmania spp. Plasmodium spp: mosquito, malaria Trypanosoma brucei: african sleeping sickness, tsetse fly

Which of the following scenarios represents appropriate detection of MRSA by the Kirby Bauer method?

MHA; direct colony suspension; 35C; cefoxitin disk; 18 hour incubation 0.5 McFarland standard 16 to 20-hour incubation 30 µg cefoxitin disk (detect mecA)

Gram-negative cocci that occur in pairs with their adjacent sides flattened, giving them a "coffee bean" appearance (indicated by the arrows in the image), are typical of which of the following bacteria?

Neisseria species Streptococcus pneumoniae: GP in pairs and chains, diplococci, oval, lancet-shaped, cat's eye, lobar pneuminia Micrococcus species: large GPC, pairs, tetrads, and clusters.

Trichuris trichiura belongs to which of the following helminth groups?

Nematodes nonsegmented, elongated, cylindrical well-developed digestive tract and reproductive system Intestinal Filariae: tissue round worm, blood sucking arthropod, mosquito / flies Trematodes: intermediate host, hermaphroditic Cestodes: tapeworms, long, ribbon-like bodies

Examine the Oxidation and Fermentation media images to the right. The image labeled as Bucket A represents what type of organism? Bucket A ferm: green ferm: blue Bucket B Ferm: green Ox: no color

Non-utilizer unable to ferment / oxidize the carbohydrate to acid byproduct Oxidizer - yellow (ox) and no color (ferm) Fermenter - yellow (ferm) and yellow (ox) Both - both aren't yellow, absence of acid byproducts

The trophozoite is the only morphologic form in the life cycle of:

Pentatrichomonas hominis nonpath parasite, large intestine, feeds on intestinal bacteria Trypanosoma cruzi: no troph, trypomastigotes and amastigotes in human, epimastigotes in bug Chilomastix mesnili: trophozoites and cysts, lemon shape, single nucleus on 1 side, prominent intra-cytoplasmic cytostome, shepherd's crook, flagellate, thin smooth cell wall, distinct anterior knob Retortamonas intestinalis: trophozoites and cysts, lemon shape

Thick Giemsa-stained blood smears are primarily used to screen for the presence of:

Plasmodium species cytoplasm stains blue nuclear material stains red/purple Paragonimus westermani: unembryonated egg, lung fluke, stool, medium, smooth, slight thickened shell, prominent opercular shouldered, most common, freshwater snails are host, brown color, undercooked crayfish or crabs Toxoplasma gondii: pear-shaped or crescent-shaped tachzoites, Wright-Giemsa / periodic acid schiff stain, PCR, serological testing, ability to cross the placenta, pregnant females - cat feces, undercooked meat invade cells, not RBC Onchocerca volvulus: river blindness, filarial nematode, tissue nodules, adult worm, tissue / skin, microfilaria, subcutaneous infection, lymph nodes and eye Brugia: filariasis, bloodstream, elephantitis, filarial nematode, lymphatics of the inguinal region, 2 nuclei in tail

Which malarial parasite is most likely present in a stained blood smear that reveals giant platelets, many reticulocytes containing Schüffner's dots, large ring forms, and schizonts with 12-24 merozoites?

Plasmodium vivax Schüffner's dots ring forms in all stages schizonts with 12-24 merozoites Plasmodium falciparum: no Schüffner's dots or schizonts, crescent shaped, double rings, rings with 2 chromatin dots, early ring forms Plasmodium malariae: no Schüffner's dots, 6-12 merozoites, rosette, Plasmodium ovale: James' stippling, 6-12 merozoites, schizonts fill entire cell, scattered schuffner's dots

Purulent material is obtained from a carbuncle and submitted for bacterial culture. Many Gram positive cocci and white blood cells were seen on direct smear (top right image). Colonies on blood agar are, smooth and gold/yellow surrounded by a narrow zone of beta hemolysis (top left image). Coagulase tests are shown in the bottom images. The slide coagulase test is negative, but the tube coagulase test is positive. The probable presumptive identification is:

Staphylococcus aureus smooth, golden-yellow, beta, grape like, GPC, Coag staph epiderm: white, raised, convex, non hemolytic, cat, coag neg, novobiocin (S) staph sapro: coag neg, novobiocin (R), smooth, non pigmented, GPC, loose cluters / tetrads, UTI, non grape like

An alpha-hemolytic slightly concave isolate from a respiratory specimen gave a zone of inhibition of 18 mm around the optochin disk. What should the next step be?

Report this organism as Streptococcus pneumoniae. Optochin disks are used for identification Not Viridans streptococci b/c optochin (S)

Each of the following statements regarding Rickettsiaceae is correct EXCEPT:

Rocky Mountain spotted fever is almost always geographically restricted to the Rocky Mountain region. southeastern parts of US some pacific coast east of the Rocky Mountains Serodiagnosis using enzyme immunoassay or indirect immunofluorescence methods is preferred over the Weil-Felix reaction to diagnose rickettsial disease. Most cases of ehrlichiosis are transmitted by the Lone Star tick. Rickettsia rickettsii is the agent of Rocky Mountain spotted fever.

The rhabditiform larva shown in this image was observed in a mount prepared from a diarrheal stool specimen. This patient also complained of persistent cough and increased shortness of breath. From the list of answer choices below, what presumptive identification can be made? (rounded end)

Strongyloides stercoralis short buccal cavity genital primordium in 1/3 from tail Trichuris trichiura: infective ovum, adult worms in intestines, eggs in stool Ancylostoma duodenale: hookworm, long buccal cavities Necator americanus: long buccal cavities

A tech is testing a sorbitol negative isolate for possible E.coli O157: H7 from the MacConkey with sorbitol agar plate. The biochemical identification proves the organism is E.coli. Serological testing for the O157 somatic antigen is positive. Serological testing for the H7 flagellar antigen is negative. Quality control for all serological testing passed. What should the tech do next?

Subculture the organism to motility medium for repeat H7 serological testing increase the production of the flagella repeat testing to show agglutination and correct the discrepancy no indication of issues with the testing quality control passed and the results should be valid

A patient came into the emergency department with a swollen knee and the physician drained 20 mL of fluid from the patient's knee. What is the name of the fluid collected?

Synovial fluid infections or inflammation arthritis Pleural fluid: pleural space (between chest wall and lungs) from thorax called - thoracentesis, pleural, or empyema fluid Ascitic fluid: from abdominal cavitity, paracentesis or peritoneal fluid, inflammatory or infectious process, liver disease or trauma Pericardial fluid: surrounding heart

Organisms such as coagulase-negative Staphylococcus, Corynebacterium, and alpha streptococcus species are all found on the skin and represent normal skin flora. All of the following are functions of normal skin flora EXCEPT?

They aid in the transmission of nosocomial infections hospital acquired infections, spread of drug resistant bacteria (MRSA, CRE, VRE) provide substances that are toxic to other organisms they inhibit growth of more harmful microorganisms they provide a level immunity to protect against the formation of infections

All of the following statements concerning Rickettsia species are ture, except:

They are cultured in many hospital laboratories. only research or reference laboratories They are obligate intracellular parasites. They are gram-negative bacilli. Associated diseases are usually diagnosed by serology

Enterobius vermicularis ova - ovoid in shape with one side flattened. The embryo is separated from the shell by a clear space.

True Enterobius vermicularis (pinworm) -ovoid in shape -one side flattened Trichomonas -highly motile -characteristic pear shape -multiple anterior flagella Schistosoma haematobium -forked tail cercaria -feces/urine -bladder fluke -inhabits veins -etiology of carcinoma of the bladder -ova are elongated -yellowish color -slightly transparent -delicate terminal spine. -large, thin, smooth shell, small spiked spine, no operculum Sperm -oval body -long thin tail