LabCE.2016.2.Microbiology

The tubes shown in this photograph reading from left to right are Kligler Iron Agar (KIA), tryptophane broth for detecting indole and Simmon's citrate. The KIA tube shows an entirely yellow slant and butt, the indole tube shows a layer of red color, and the Simmon's citrate tube is green in color. Of the bacterial species listed, the one most likely to produce the reactions observed is:

Escherichia coli

Illustrated in this photograph is an H & E-stained section of a gastric biopsy obtained from a patient with suspected peptic ulcer disease. Based on the biopsy findings, the bacterial species that would most likely be recovered is:

Helicobacter pylori

Streptococcus pneumoniae can BEST be differentiated from the viridans group of streptococci by which characteristic?

Bile solubility

Beta-lactam antibiotics interfere with cell wall synthesis by:

- Binding with a transpeptidase - Preventing the final stage of peptidoglycan synthesis - Interfering with PBPs All of the above

In traditional culture or antigen detection methods, the sensitivity of detection is adversely affected by which of the following? (Choose all that apply.)

- Fastidious growth requirements - Delays in transport - Specialized media requirements

Procedures that may enhance the recovery of beta hemolytic, group A streptococci from throat cultures include:

- Incorporation of sulfamethoxazole and trimethoprim in the culture media - Incubation under anaerobic conditions

This suspicious form was found in stool.

Pseudoparasite

Match each of the clinical syndromes listed with its most likely bacterial species.

Intrauterine device related endometritis- Actinomyces israelii Appendical abscess - Bacteroides fragilis "Floppy infant" syndrome - Clostridium botulinum Bacterial vaginosis - Mobiluncus curtisii

I measure 12 micro meters and am found in stool.

Iodamoeba butschlii cyst

Which malaria infection is associated with massive hemolysis, blackwater fever, and blockage of capillaries?

Plasmodium falciparum

The saccharolytic anaerobe that produces red fluorescing colonies when illuminated with a Wood's lamp, as shown in this photograph, is:

Prevotella bivia

What is the anatomical feature of a tapeworm that possesses both male and female reproductive structures?

Proglottid

Arrange in ascending order the names of the Mycobacterium species listed below, from the slowest to the most rapid, in the rates of growth on agar media when recovered from clinical specimens:

Second Mycobacterium tuberculosis Third Mycobacterium gordonae Fourth Mycobacterium fortuitum First Mycobacterium malmoense

The McFarland Comparison Card shown in the illustration is used to:

Standardize concentrations of organisms

The detection of a distinct odor is often helpful in the presumptive identification of bacterial culture isolates. Match each of the odors listed with its corresponding bacterial species name.

Streptococcus anginosus (milleri) Butterscotch Pseudomonas aeruginosa Grapes Eikenella corrodens Bleach Alcaligenes faecalis Pared apples

The most frequent cause of bacterial meningitis in older adults is:

Streptococcus pneumoniae

Pigment production is a key initial assessment in the presumptive identification of the nonfermentative gram negative bacilli. Label each of the bacterial species listed below by their colony pigmentation (yellow or nonpigmented).

Yellow Pigment Burkholderia cepacia Nonpigmented Acinetobacter lwoffii Yellow Pigment Stenotrophomonas maltophilia Yellow Pigment Flavimonas oryzihabitans

Multiple ring forms are most frequently seen in which Plasmodium?

falciparum

Which of the following best describes the organisms seen in this illustration:

gram-variable

Which enzyme is responsible for joining the reverse-transcribed HIV DNA to the host cell's DNA?

Integrase

Which substance acts as a mordant in the Gram Stain process?

Iodine

The CAMP reaction is most helpful in the identification of beta hemolytic streptococci, group B (shown in the photograph as the arrowhead-shaped zone of hemolysis at the tip of the red arrow). A beta hemolytic gram positive bacillus that produces the rectangular-shaped area of hemolysis as shown by the blue arrow in the photograph is:

Listeria monocytogenes

Which method is employed if the following procedural steps were used to identify M. kansasii? 1 - Extraction 2 - Denaturization 3 - Hybridization 4 - Hydrolysis of excess reagent 5 - Detection of acridinium ester

Nucleic acid probes

A yellow pigmented nocardioform bacterial species was recovered from repeated sets of blood cultures. It was non acid fast, motile and the filamentous mycelium broke up into fragments as the culture matured. The most likely identification is:

Oerskovia turbata

A blood culture yielded the organism with the following reactions: TSIA . . . . . . . . . . . . . . . . . . . K/A, Gas (+), H2S (+) Citrate . . . . . . . . . . . . . . . . . Positive Indole . . . . . . . . . . . . . . . . . Negative Lysine . . . . . . . . . . . . . . . . . Positive Ornithine . . . . . . . . . . . . . . Positive Motility . . . . . . . . . . . . . . . . Positive Phenylalanine. . . . . . . . . . . . Negative This organism can be identified as:

Salmonella

A beta-hemolytic gram-positive coccus, isolated from the CSF of an infant, grew on sheep blood agar under aerobic conditions and was resistant to a bacitracin disc. Which of the following tests should be performed for the presumptive identification of the organism?

CAMP test

The colonies shown in this photograph were grown on Guizotia abyssinica (bird seed) agar at 30°C for 72 hours. The most likely identification is:

Cryptococcus neoformans

Which of the following molds is classified as a zygomycete?

Cunninghamella species

Illustrated in the upper photograph is a 5% sheep blood agar plate after 24 hours incubation at 42°C following application of a stool suspension to a 0.45um micropore filter paper disk. The lower photograph shows the spot reaction of the isolate on an indoxyl acetate reagent disk. The most likely identification is:

Campylobacter upsaliensis

A fusiform-shaped, gram negative, oxidase negative bacillus that produces colonies with marginal finger-like projections was recovered from the oral cavity of a patient with periodontal disease. The most likely identification is:

Capnocytophaga ochracea

In the gold rush days of yore, Rice water stools at death's door.

Cholera

Which of the following fungal infections is endemic in the southwestern US desert regions?

Coccidioidomycosis

Match the name of each of the dimorphic fungi listed with the corresponding activity by which infection can be avoided.

Coccidioidomycosis Practice dust control Histoplasmosis Avoid roosting areas of birds Sporotrichosis Protect against thorn punctures

Oral candidiasis may be directly exacerbated by the habitual ingestion of:

Cola

Stenotrophomonas maltophilia and Burkholderia cepacia share each of the following characteristics except:

Cytochrome oxidase activity

Match each of the names of the dimorphic fungal species with its corresponding mold form as seen in the photomicrographs.

Histoplasma capsulatum Upper left Coccidioides immitis Upper right Blastomyces dermatitidis Lower left Sporothrix schenckii Lower right

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." This patient is most likely suffering from:

Intestinal amebiasis

Match the names of each of the bacterial species listed with its most distinguishing identifying characteristic listed.

Listeria monocytogenes - Room temperature motility Erysipelothrix rhusiopathiae - H2S production Gardnerella vaginalis - "Whiff" test Bacillus mycoides - Lecithinase production

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

Log Phase

Erythema migrans, spirochetemia and chronic arthritis are three stages in the progress of:

Lyme disease

Which one of these characteristics distinguishes vancomycin-resistant Enterococcus faecium and Enterococcus faecalis from other Enterococcus species?

Non-motility

Match the name of each of the bacterial species listed into the appropriate bucket indicating whether it produces a red or a yellow pigmented colony when growing on 5% sheep blood agar.

Yellow colonies Enterobacter sakasakii Red colonies Serratia rubidea Yellow colonies Pantoa agglomerans Yellow colonies Ewingella americana

Which one of the following descriptions about Pasteurella is FALSE?

Grows well on MacConkey agar.

Who am I in this cul de sac Appearing as a patch of black.

Salmonella typhi

The reactions seen in the tubes presented in this photograph reveals a motile, gas producing, lactose fermenter that produces acetyl methyl carbinol in VP broth and utilizes sodium citrate as the sole source of carbon. The most likely identification is:

Enterobacter aerogenes

I am a most jolly fella, Capped with my polar flagella.

Burkholderia cepacia

Label each of the Kligler Iron Agar reactions shown in the photographs by the name of the most likely associated bacterial species:

Enterobacter cloacae A Shigella sonnei B Proteus mirabilis C Burkholderia cepacia D

As a gram positive coccus I've become a bit fancy, Short chains and motile, plus I carry the gene VanC.

Enterococcus cassiloflavus

The disease most commonly associated with the novobiocin-resistant staphylococcus illustrated in this photograph is:

Acute cystitis

Pseudomonas aeruginosa is often used as a bacterial species for the quality control of Kligler Iron Agar. The expected reaction is:

Alkaline slant/alkaline deep

Match the names of each of the bacterial species with its most likely associated test reactions as shown in the photographs. The photographs reading from left to right are: bile esculin/6.5% NaCl (Image A); bile esculin/6.5% NaCl (Image B); motility agar (Image C), and OF dextrose, closed and open tubes (Image D).

Enterococcus faecalis A Streptococcus group D B Enterococcus casseliflavus C Micrococcus luteus D

Match the names of each of the bacterial species listed with the name of its associated virulence factor listed.

Enterococcus faecalis Lipoteichoic acids Streptococcus pneumoniae Polysaccharide capsule Streptococcus pyogenes M protein Staphylococcus aureus Protein A

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

Epstein-Barr Virus

What is the antigen carried by most strains of Streptococcus anginosus (milleri)?

F

Match the group of antibiotics listed in the left column that are associated with specific species of organisms for which resistance has emerged.

Klebsiella pneumoniae Cephalosporin resistance Staphylococcus aureus Methicillin resistance Streptococcus pneumoniae Intermediate penicillin resistance Enterococcus faecium Vancomycin resistance

Match the name of each of the bacterial species listed with the appropriate bucket indicating whether it is a lactose fermenter or a non lactose fermenter.

Late lactose fermenter Serratia marcescens Non lactose fermenter Proteus mirabilis Lactose fermenter Enterobacter aerogenes Lactose fermenter Klebsiella oxytoca

The anaerobe producing the double zone of hemolysis, seen in this photograph, can be presumptively identified as Clostridium perfringens. The enzyme producing the outer zone of hemolysis is:

Lecethinase

A culture from a sputum specimen grew a mucoid, lactose fermenting organism. Biochemical testing on this isolate gave the following key reactions: VP: positive, Urea: 1+, Motility: nonmotile, citrate: positive. These reactions are helpful in separating Klebsiella from Escherichia coli.

True

Acute gonorrhea is the most common cause of septic arthritis in patients under 30 years of age.

True

Most infections caused by S. anginosus can be effectively treated with penicillin or a first generation cephalosporin.

True

Shown in the image are three tubes: (1) motility agar (note subsurface flare shown by arrows); (2) esculin hydrolysis (+), and (3) VP (+). The reactions illustrated here are sufficient to rule out Erysipelothrix rhusiopathiae.

True

In the ancient tombs of Isis, Mummies lie dead from phthisis.

Tuberculosis

Stomatococcus mucilaginosus is a member of the family Micrococcaceae that has been associated with endocarditis in patients after cardiac catheterization or in intravenous drug users. Tests that are helpful in making a species identification include:

- Presence of a capsule - Failure to grow in 5% NaCl

Which of the following organisms are most frequently associated with infective endocarditis?

- Staphylococci - Streptococci

The ends of rod-shaped bacteria may appear:

- tapered - rounded

In patients who present with a classic "strep throat", the beta hemolytic, catalase negative gram positive bacillus that must be included in the differential diagnosis is:

Arcanobacterium (Corynebacterium) haemolyticum

Based on the structures observed in this photomicrograph, the most probable species of the fungus recovered from an induced sputum specimen is:

Aspergillus nidulans

From the ancient books of lore Name the bug that has this spore.

Bacillus anthracis

Which of the following growth factor(s) is necessary for the proper culture of Haemophilus influenzae:

Both X and V factors

Match the names of each of the Staphylococcus species with Bucket A if it can produce acid from mannitol and with Bucket B if it is mannitol negative.

Bucket A - Staphylococcus aureus Bucket B - Staphylococcus saprophyticus Bucket B - Staphylococcus epidermidis Bucket A - Staphylococcus xylosus

Match the name of each of the bacterial species listed into Bucket A (absence of fluorescence = positive test) or Bucket B (negative) depending on whether or not esculin is hydrolized:

Bucket B Plesiomonas shigelloides Bucket A Enterococcus faecium Bucket B Prevotella melaningogenica Bucket A Aeromonas hydrophyla

Shown in this photograph are three tubes of Moeller decarboxylase broths, containing from left to right, the amino acids lysine, arginine and ornithine respectively. A red-blue reaction indicates decarboxylation of the amino acid; yellow is negative. Of the bacterial species listed, these reactions are most likely caused by:

Enterobacter aerogenes

Arrange the names of the bacterial species listed in ascending order of least pathogenic to most virulent based on the severity of the human infections they may cause.

First Corynebacterium cystitidis Fourth Bacillus anthracis Third Listeria monocytogenes Second Nocardia brasiliensis

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

Which one of the following fungi is MOST likely to be found as a common saprobe and as a cause of keratitis?

Fusarium

Match the vocations or avocations listed with the bacterial species that would most likely be associated with work-related infections.

Goat cheese processor Listeria monocytogenes Sword swallower Actinomyces israeli Food caterer Bacillus cereus Taxidermist Bacillus anthracis

This member of the Enterobacteriaceae is shown on triple sugar iron agar, lysine iron agar, urea agar, citrate agar , phenylalanine deaminase agar, and motility indole ornithine agar. It should be identified as:

Providencia spp.

HIV is known as a retrovirus because:

RNA is used as the template for DNA synthesis

Which are true statements regarding hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) and community-associated MRSA (CA-MRSA)?

Resistance for both strains is conferred by the mecA gene. HA strains tend to demonstrate resistance to more drug classes than CA strains. CA tends to be associated with the PVL gene and skin and soft tissue infections. All of the above.

In order to avoid falsely elevated spinal fluid cell counts one should:

Select an aliquot from the last tube collected

The dimorphic fungus that may produce black, yeast-like colonies after prolonged incubation at 37°C is:

Sporothrix schenckii

The colonies shown in the upper image, obtained from a biopsy of an ulcerating skin lesion of the arm, are growing on agar slants of Sabouraud's dextrose agar. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony growing in the left slant. The diagnosis is:

Sporotrichosis

The slide coagulase test is a rapid method for identifying which of the following organisms.

Staphylococcus aureus

Each of the bacterial species listed below may be associated with culture-negative endocarditis except:

Staphylococcus epidermidis

Koch's postulates include all of the following except:

The isolated organism, when injected into a human host, will produce the disease

Which of the following is NOT a characteristics of Burkholderia pseudomallei?

Fat, gram-postive rod

Minimum inhibitory concentration (MIC) susceptibility tests should be performed against other beta lactam antibiotics on important S. pneumoniae isolates from blood cultures and other sterile body fluids when a MIC for penicillin is performed.

False

Illustrated in this photograph are latex agglutination reactions of an unknown beta hemolytic streptococcus recovered from a blood culture. Of the choices in this exercise, the most likely primary infection with the bacterial species represented is:

Deep wound cellulitis

The organism pictured below was a Gram-positive rod isolated from a sore on the hand of a fish market employee. It is shown on triple sugar iron agar. What is the most likely identification if it is catalase negative and non-motile?

Erysipelothrix rhuziopathiae

A patient who was seen in the ED has symptoms consistent with cellulitis. A Gram stain from the patient's blood culture revealed Gram-positive cocci in pairs and short chains. Blood cultures grew an organism that was susceptible to a 0.04 unit disk of bacitracin. Other characteristics one would expect to see are:

Beta hemolysis, negative catalase, negative CAMP, no growth in 6.5% salt

The culture medium that is specifically formulated to recover Salmonella typhi from stool specimens is:

Bismuth sulfite agar

The colonies shown in this 5% sheep blood agar (left) and MacConkey agar (right) split frame photograph are most likely those of:

Morganella morganii

Each of the following characteristics is prerequisite for a bacterial species to be classified within the Family Enterobacteriaceae except:

Motility via peritrichous flagellae

The most likely organism to be cultured on the Lowenstein-Jensen agar slant illustrated here would be:

Mycobacteria

MacConkey agar without crystal violet is a culture medium useful in the presumptive identification of:

Mycobacterium fortuitum

Match each of the names of the Mycobacterium species listed with its associated colonies illustrated in photographs:

Mycobacterium tuberculosis A Mycobacterium kansasii B Mycobacterium scrofulaceum C Mycobacterium fortuitum D

From the list of bacterial species, match each with the name of the test that would be most helpful in making a species identification.

Mycobacterium tuberculosis Niacin accumulation Streptococcus pneumoniae Optochin Providencia stuartii Phenylalanine deaminase Campylobacter jejuni Indoxyl acetate

Which of the following is a common contaminant that grows rapidly, is at first white and then becomes bluish-green and very powdery with spore-bearing hyphae that characteristically form a brush? (The conidia are unbranched chains arising from sterigmata that are arranged in whorls.)

Penicillium

The select reactions observed in the partial API strip illustrated in this photograph, reading from left to right, are: ONPG negative; arginine, lysine, and ornithine decarboxylases positive; citrate positive; H2S positive, and the remaining reactions negative. These reactions are most consistent with bacteria belonging to the genus:

Salmonella

The type of health-care occupational exposure with the greatest risk of HIV transmission is:

a percutaneous injury