Micro

Prior to receiving antibiotic therapy, a patient had a urinary tract infection with gram-negative, motile rods producing the following reactions:Indole: pos.H2S (TSI): pos. MR: pos. VP: neg.Phenylalanine deaminase: pos.Urea: pos.Citrate: pos.Ornithine decarboxylase: neg.Gelatin hydrolysis: pos. Based on the reactions above, what organism is MOST likely causing the infection?

Proteus vulgaris

______________________ is predominantly associated with skin and soft tissue infections (SSTIs), such as abscesses, cellulitis, folliculitis, and impetigo.

Community-associated MRSA

An abdominal wound culture grows E. coli on the aerobic culture. The anaerobic culture has growth of two gram negative rods, one of which is aerobic. The other gram negative rod has 2+ growth on BBE plate and is resistant to Kanamycin, Colistin, and Vancomycin disc. This organism can be identified as:

Bacteroides fragilis group

Illustrated in the upper composite photograph are non-hemolytic, smooth, entire non-pigmented white colonies growing on blood agar. Human isolates are most commonly from nosocomial infections related to endotracheal tubes and tracheostomies, with peritonitis inpatients receiving peritoneal dialysis. Distinctly light lavender-pink pigmented colonies are observed growing on MacConkey agar. Tiny coccobacilli simulating those of Neisseriaspecies are observed in gram stains as illustrated in the lower photmicrograph. Other identifying features include the oxidative production acids from most carbohydrates (saccharolytic) and a negative oxidase test. From these observations, select from the multiple choices the presumptive identification of this isolate.

Acinetobacter baumannii

A major difference between Salmonella enterica and Shigella infections is that ONLY in salmonellosis can which of the following be observed?

Animals serve as a reservoir of infection.

A gram-negative coccobacillus produces small gray colonies surrounded by a zone of hemolysis on a potato-blood-glycerol agar. The organism also grew on chocolate agar, but NOT on sheep blood agar. This is MOST likely to be which organism?

Bordetella pertussis

Surprise! Animals are not the only creatures with bacteria. The bacterial species causing onion rot is:

Burkholderia cepacia

Spinal fluid cultures on a 3-day-old infant revealed beta-hemolytic, Gram-positive cocci occurring in pairs and chains. The organism was catalase-negative and bile esculin-negative. Resistance to 0.04 U disk of bacitracin was noted. The other test necessary to identify this organism is a positive test by

CAMP

A decrease in which of the following in AIDS patients results in increased susceptibility to infection

CD 4+ cells

The isolate is represented by the slow growing small, gray-white, opaque and non-hemolytic colonies on blood agar. Short, gram-negative bacilli are, lying singly but also in the form of characteristic "rosette-like" clusters (arrows) are observed in the lower photomicrograph. As additional biochemical reactions necessary to confirm a presumptive identification, oxidase and indole reactions are positive; catalase, nitrate and urease reactions are negative. Based on these observations, select from the multiple choices the presumptive identification of this isolate.

Cardiobacterium hominis

Trypanosoma cruzi is the etiologic agent of

Chagas' disease

The media used to isolate Legionella pneumophilia should contain which of the following additives

Charcoal and yeast extract

A recto-sigmoidoscopy revealed pseudomembranes in a patient with severe diarrhea following prolonged treatment with ampicillin. Which of the following organisms is MOST likely to be isolated?

Clostridium difficile

The irregular-sized, gray-white colonies, with irregular margins as shown in the image to the left in the upper composite photograph were recovered from a stool specimen in a case of antibiotic associated colitis. The colonies are flat, gray-white and spreading with irregular margins. Some patients with this infection develop pseudo-membranous colitis that can be life threatening. Growth is enhanced when Cycloserine-cefoxitin-fructose agar (CCFA) is used, as seen in upper right photograph. The observation of elongated, gram positive bacilli with distinctive sub-terminal and central spores in gram stain mounts provides for a presumptive identification. An additional key identifying biochemical reaction is the hydrolysis of esculin and gelatin. With these observations, select from the multiple choices the presumptive identification of this isolate.

Clostridium difficile

The flat, spreading gray-white colonies with an outer zone of beta hemolysis as observed on the surface of an anaerobic blood agar plate (upper photograph) were recovered from a blood culture of an elderly man leading to a potential diagnosis of cancer of the colon. Observed in the gram stain are short gram-positive bacilli, some with distinctive central and sub-terminal spores. From these observations, select from the multiple choices the name of this isolate

Clostridium septicum

Which one of the following organisms is commonly cultured from the nasopharynx of healthy people but is RARELY pathogenic

Corynebacterium species

The India ink preparation is used as a presumptive test for the presence of which organism

Cryptococcus neoformans in CSF

The infective stage for the majority of all intestinal amoebae is the

Cyst

A definitive diagnosis of malaria can be made by

Demonstration of the organisms in peripheral blood

The colonies illustrated on the blood and chocolate agar plates represent a slow-growing bacterial species that is endogenous in the oral cavity and upper respiratory tract, but may be recovered from human bite skin infections incurred during fist fights. Note the pitting of the agar surrounding the colonies growing in the chocolate agar plate. The Alk/Alk non fermentative reaction seen in the Kligler Iron Agar tube to the left in the lower photograph indicates the non fermentation of glucose, also indicated by the lack of carbohydrate assimilation in the individual carbohydrate reaction tubes to the right of the KIA tube. A reduction of nitrate demonstrated and decarboxylation of ornithine are the positive reactions included in this exercise. From these observations, select from the multiple choices identification of this bacterial isolate.

Eikenella corrodens

reside in the mouth where I measure approximately 17 micro meters.

Entamoeba gingivalis trophozoite

What is the primary target of the Hepatitis B virus?

Liver

An alpha-hemolytic streptococcus isolated from a wound is resistant to optochin and bacitracin, grows in 6.5% NaCl broth, and is PYR positive. The organism is MOST likely a streptococcus belonging to

Enterococcus

As a gram positive coccus, I've become a bit fancyShort chains and motile, plusI carry the gene VanC.

Enterococcus cassilflavus

Illustrated in the top photograph is a 4-day growth of silky, light gray-white to yellow colonies grown on Sabouraud's dextrose agar and incubated at 30 degrees C, recovered from an "athlete's foot" infection (tinea pedis) of a young football player. Note the projection of delicate hyphae to the periphery of the colonies. The identification can be made by observing the conidia formations in the lactophenol blue stained mount prepared from the surface of one of the colonies. With these observations, select the species identification from the multiple choices.

Epidermophytons floccosum

Which two of the following organisms are gram-positive? Pasturella Erysipelthrix Aeromonas Lactococcus

Erysipelthrix and Lactococcus

The well circumscribed cutaneous papule with the distinct outer erythematous border illustrated in the upper photograph developed over a period of 5 days at the site of a tick bite. The lower photograph illustrates colonies growing on a buffered charcoal yeast extract agar plate that had been inoculated with material from the ulcer bed three days before. Tiny, pale-staining gram negative coccobacilli were seen on a gram stain. The most likely causative agent is

Francisella tularensis

Observation of each of the following characteristics is helpful in differentiating between Nocardia species and Mycobacteriumspecies except:a. Partial acid fast staining b. Filamentous rods that branch c. Musty basement smell of the colonies d. Gram positive staining

Gram postive staining

The biochemical testing results of an alpha-hemolytic streptococcus show that the isolate is bile esculin-positive, but does not grow in the presence of 6.5% NaCl. The MOST probable identity of this isolate is what?

Group D streptococcus, non-enterococcus

The combination of organisms that is correctly paired with the reactions for appropriate quality control (one organism positive for the reaction and one organism negative for the reaction) are:

Indole: Escherichia coli and Proteus mirabilis

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

Iodine

Which one of the following statements about E.coli O 157:H7 is false

It ferments sorbitol rapidly

Which one of the following statements about Coxiella burnetti is not true

It is best diagnosed by culture of the organism

An 87-year old patient had a foot wound that grew gram-negative rods on MacConkey agar as pink to dark pink oxidase-negative colonies along with the following results:TSI: A/AIndole: neg.MR: neg.VP: pos.Citrate: pos. H2S: neg.Urea: pos.Motility: neg.Ornithine: neg.Antibiotic susceptibility: Carboxicillin and ampicillin resistant, all others sensitive.What is the MOST likely organism?

Klebsiella pneumonia

If CFS tubes numbered #1, #2, and #3 CANNOT be analyzed within one hour, the correct procedure for the microbiology sample tubes is to:

Leave at room temp

Which bacterial species is a common agent of neonatal bacteremia?

Listeria monocytogenes

Which of the following species of Mycobacteriummight be associated with contamination of the hot water system in large institutions such as hospitals?

M. xenopi

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

Modified dimethyl sulfoxide (DMSO) test

Surprise. The purulent exudate the intracellular bacteria (shown by the arrows) as illustrated in this photomicrograph was observed in a direct sputum Gram stain of a 70 year-old patient with chronic obstructive pulmonary disease. The bacterial species that most likely grew out in culture is:

Moraxella catarrhalis

An acid-fast bacillus is isolated and produces an orange pigment when grown in either the light or the dark. Which type of organism has most likely been isolated?

scotochromogen

Small, gray-white colonies, as observed growing on 7-H10 agar to the left in the upper composite photograph, were recovered from an upper respiratory specimen after 7 days incubation. This Mycobacteriumspecies in the past was uncommonly recovered from human infections until the advent of AIDS when it became an agent of pulmonary and other infections. Notably, colony isolates from patients with AIDS have developed a pale yellow pigmentation that does not intensify with light exposure (right image in upper composite photograph). The acid-fast bacilli as observed in the lower photomicrograph are short and lie singly or in loose clusters. From these observations select from the multiple choices the presumptive identification of this isolate.

Mycobacterium avium/intracellulare

The Mycobacterium species capable of growing on modified MacConkey agar (crystal violet removed from the formula), as illustrated in this photograph, is:

Mycobacterium fortuitum

Which organism is a cell wall deficient bacterium that commonly causes atypical or "walking pneumonia?

Mycoplasma pneumonia

As one of the aerobic actinomycetes, the light yellow, entire, convex, smooth, non hemolytic colonies are observed on blood agar. The gram stain, showing gram-positive bacilli, with filamentous forms seen in younger cultures, is not distinctive. Key to the identification is the hydrolysis of casein, as seen in the lower photograph. Xanthine was not hydrolyzed. The presumptive identification is:

Oerskovia turbata

The increased resistance of MRSA strains to beta-lactam antibiotics is due to production of which of the following penicillin binding proteins (PBPs)?

PBP 2a

MacConkey agar contains all of the following except

Penicillin

Illustrated in this image is the fruiting head of one of the fungal agents of chromomycosis. Note the long urn-shaped phialides tapered at the ends and topped with a distinctive flat, saucer shaped cap. Which of the following choices represents the type of sporulation illustrated in this image?

Phialophora sporulation

In observing the slow-growing , 7-day-old dark brown colonies growing on Sabouraud Dextrose with Grain Heart Infusion (SABHI) agar, note the black pigment that extends to the reverse of the colony. This provides for a presumptive indication of one of the fungi involved in chromoblastomycosis. The species identification of this fungus can be made by observing the distinctive fruiting heads illustrated in the bottom image. From the list of choices below, select the identification of the fungal species presented.

Phialophora verrucosa

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

Plasmodium species

The Xylose Lysine Decarboxylase medium shown in this photograph was isolated from a stool specimen on an immunocompetent adult. Your best action would be to:

Report it as no Salmonella or Shigella isolated.

If a CAMP test had an arrowhead appearance, the bacitracin disk had a zone of 6 mm with a 6 mm disk, the bile esculin was tan throughout, and the SXT disk had a zone of 6 mm with a 6 mm disk, the action you should take would be:

Report the isolate as Beta streptococcus Group B

Which of these laboratory methods are recommended for confirmation of influenza A H1N1 subtype infection?

Reverse transcriptase-polymerase chain reaction (RT-PCR)

What test(s) that are the most useful in separating Listeria monocytogenesfrom Erysipelothrix rhusiopathiae?

Room temperature motility Catalase Esculin hydrolysis

Multiple young 3-day old colonies having a low cottony surface mycelium that upon maturity develop a distinctly gray pigmentation (referred to as "house mouse gray"). The reverse of the colony remains light gray in color and does not show the darker pigmentation. Microscopic examination of a small inoculums from the surface of the colony is illustrated in the lower photomicrograph. From the list of multiple choices, select the genus name of the fungus being represented.

Scedosporium

Which one of the following parasites migrates through the circulation (blood) before maturing in the portal venous system?

Schistosoma mansoni

The Quellung test is useful for which of the following:

Serological typing of Streptococcus pneumoniae

In the upper bi-plate image are shown colonies growing on MacConkey, 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 pigmentation 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 DNA'se agar in the lower image 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

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

Staph and Strep

Who are we huddled here so tight, Like clusters of stars in the night.

Staphlyococcus epidermis

The entire, smooth, golden yellow-pigmented non-hemolytic colonies on the surface of the blood agar plate seen in the upper image have been recovered in hospital acquired infections from patients with cystic fibrosis. A Gram stain prepared from one of the colonies as shown in the lower image, reveal long, narrow gram-negative bacilli arranged singly. Polar flagella would be seen in flagellar stains. All carbohydrate reactions are negative except for the oxidative utilization of maltose. Positive biochemical reactions for DNA'se and for esculin assist in making a definitive identification. Based on these observations, select from the multiple choices the identification of this isolate.

Stenotrophomonas maltophilia

In molecular diagnostic testing, hybridization employs complementary base pair binding of a synthetic strand to DNA or RNA.

true

The federal government has categorized critical biological agents into three groups: A, B, and C. Why are the agents in category A classified as the highest priority?

These organisms can be easily disseminated or transmitted person-to-person.

Which of these nitrogenous bases is present in deoxyribonucleic acid (DNA), but not in ribonucleic acid (RNA)?

Thymine

Chlamydia trachomatis causes which of the following problems?

Trachoma, a major cause of preventable blindness in the world

Illustrated in the composite photograph is an inflammatory reaction of skin with erythema and micro-pustule formation, most consistent with a dermatophyte infection. The lactophenol blue mount was prepared from a 4-day old colony grown from the skin lesion as shown. The accompanying lactophenol blue microscopic mount illustrates small, spherical micro conidia arranged in loose clusters along the sides of thin hyaline hyphae. The species identification can be confirmed by the positive urease reaction as

Trichophyton mentagrophytes

Illustrated in the top photograph is the picture of a yellow to buff colored colony, suede-like in consistency, recovered from a hairless inflammatory lesion of the skin of the scalp of a young male athlete. The more definitive identification can be made from observation of the lactophenol blue mount illustrated in the bottom photomicrograph, prepared from a small sample of the colony surface mycelium. Based on these observations, select from the multiple choices the presumptive identification

Trichophyton tonsurans

Illustrated in the photograph is what appears to be a tapeworm strobili in which the individual proglottids appear broader than long. If this segment was observed in a stool specimen, select from the multiple choices the presumptive identification

Vegetable artifact

The fastidious gram negative bacillus featured here has been recovered from individuals in pandemic outbreaks of diarrhea after ingestion of contaminated stream, lake, or well water. In many cses, life-threatening profuse diarrhea resulting in dehydration and electrolyte loss is often experienced. Smooth, entire, convex light gray yellow colonies are observed on blood agar (left upper image). Note the yellow pigmentation of the colonies growing on TCBS agar (Thiosulfate Citrate Bile Sucrose) on the right of the composite image, indicating strong acid production from sucrose. Cytochrome oxidase is also positive. Small, curved and S-shaped, gram-negative bacilli are seen on Gram stain. From these observations, select from the multiple choices the correct genus/species identification of this isolate.

Vibrio cholerae

A small gram-negative rod isolated from an eye grows on chocolate agar but NOT on sheep blood agar. It produces satellite growth around staphylococci on sheep blood agar, however. The organism requires:

X and V facto

The stool specimen from a patient admitted to the hospital with symptoms of appendicitis has a culture with the following characteristics:Gram-negative bacillusCatalase positiveUrease positiveWeakly fermentativeTSI Slant is A/AThese reactions suggest that the organism is MOST likely:

Yerseinia enterocolitica

Illustrated in the top photograph are small, smooth, 48 hour old white yeast colonies growing on potato dextrose agar. The rudimentary spikes from the surface of the colonies (arrows) indicate that a germ tube test should be performed. The bottom image is the germ tube test for this isolate. Select from the multiple choices the identification of this yeast isolate.

Candida albicans

Which nitrogenous base would bind with thymine in forming double-stranded DNA

Adenine

A beta-hemolytic Streptococcus was isolated from a throat culture. It gave the following biochemical reactions:· Bacitracin - Susceptible· Bile esculin - Negative· 6.5% NaCl - No growth· CAMP - Negative· SXT - ResistantWhat is the presumptive identification?

Beta Streptococcus, group A

This is a catalase-positive, coagulase-negative gram-positive coccus isolated from a urine specimen from a 20-year-old college student. The image below is a Mueller Hinton plate streaked with a 0.5 MacFarland standardized inoculum and a 5 microgram disk of novobiocin after overnight incubation. What is the identification of the isolate?

Staphylococcus saprophyticus

The lecithin hydrolysis, indicated by the tips of the arrows in this photograph of an egg yolk agar plate, may be produced by each of the following Bacillus species except:

Bacillus subtilis

Which of the following is a presumptive test for the identification of Lancefield group A Streptococcus

Bacitracin susceptibility

Cultures from past-abdominal cellulitis grow gram negative pleomorphic rods with the following characteristics:Grows on KV agar but does not show fluorescenceProduced black colonies BBE agarResistant to penicillinWhich of the following is the MOST likely identification?

Bacteroides fragilis

Illustrated in the top image are small, entire gray-white colonies growing on the surface of an anaerobic blood agar plate. Hemolysis is absent. Small, gram negative coccobacilli with rounded ends are seen on gram stain. Positive biochemical reactions include strong hydrolysis of esculin, positive indole and the fermentation of glucose and other carbohydrates (saccharolytic). From these observations, select the correct identification of this isolate from the choices below:

Bacteroides fragilis

Illustrated in the top image is a 10-day-old colony growing on the surface of Sabouraud Dextrose with Brain Infusion (SABHI) agar, incubated at 30 degrees C, recovered from an induced septum sample obtained from a 42-year-old Mid-western farmer. The colonies are not genus/species specific, and appear as a mold with a delicate, silky, cob-web like yellow-white mycelium. The species identification is made by observing the Lactophenol blue-stained tease mount preparation illustrated in the bottom image. With these observations, select the presumptive identification of this isolate from the choices shown below.

Blastomyces dermatitidis

The small, slowly growing gray-white colonies seen on the blood agar plate were recovered from a blood culture of a 40-year-old farm worker who developed fever and chills leading to septicemia, following ingestion of contaminated milk. The gram stain of this organism is seen in the lower image revealing small gram-negative coccobacilli in loose clusters. Key to the identification of this blood culture isolate is the rapid urease reaction. From these observations, select from the multiple choice the presumptive identification of this isolate.

Brucella species

Illustrated in the upper photograph of the composite is the surface of a blood agar plate on which small, entire, gray-yellow colonies are observed, with yellow pigmentation shown on the cotton swab. Light pink, non-fermentative colonies are seen on MacConkey agar (composite upper right), confirmed by the Alk/Alk reaction on KIA (left tube in composite lower image). Shown in this composite also are key reactions - positive lysine decarboxylase (center), and oxidative utilization of maltose and sucrose (right). This non-fermenter is most commonly an opportunistic pathogen in cases of respiratory infection associated with chronic granulomatous disease and cystic fibrosis. From these observations, select from the multiple choices the identification of this isolate.

Burkholderia cepacia

Illustrated in the top photograph are smooth white yeast colonies growing on Sabouraud's heart infusion agar (SABHI agar) after 48 48 hours incubation at 30˚ C. The colonies were recovered from a post-operative wound infection in a 65 year old man following an organ transplant. The bottom photograph is representative of more mature colonies after an additional 24 hour incubation. From these observations, select the presumptive identification of this yeast isolate.

Candida albicans

This photomicrograph was prepared from tease mounts of 3 day-old smooth, white yeast colonies obtained from an aspirate of nasal fluid of a middle aged patient with sinusitis. Note the clusters of small blastoconidia along the pseudohyphae and also the larger spherical chlamydospores (arrow), as observed in the right lower corner. From the multiple choices, select the identification of this yeast isolate.

Candida albicans

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

Cola

Stenotrophomonas maltophilia and Burkholderia cepacia share each of the following EXCEPT for which characteristic?

Cytochrome oxidase activity

The 6 um in diameter cyst illustrated in the trichrome-stained photomicrograph was inadvertently observed in the stool specimen that was being examined for reasons not clinically related to a parasitic diseases. Further history revealed that the patient for whom the stool examination was being performed had only rare bouts of mild diarrhea. From the multiple choices listed below, select the appropriate genus/species designation to enter in the laboratory report to be sent out.

Entamoeba histolytica/dispar

The long, pencil-shaped, multi-celled, thin, and smooth-walled macroconidia illustrated in this image are characteristic of which species?

Exserohilum species

Influenza B or C related illnesses tend to be more severe than those caused by influenza A

False

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

False

Each of the following characteristics will differentiate between Listeria monocytogenes and Erysipelothrix rhusiopathiaeexcept

Fermentation of glucose

A 42-year-old chain smoker experienced an increase in cough, sputum production, and intermittent shortness of breath for over one week. A diagnosis of chronic bronchitis with acute exacerbation was made. The image shows a Gram stain of an early morning, spontaneously expectorated sputum. Based on the pleomorphic coccobacilli shown in the Gram stain, what is the most likely cause of the exacerbation?

Haemophilius influenza

The mechanism by which certain strains of Enterococcusspecies have developed resistance to the synergistic combination of aminoglycoside and beta-lactam antibiotics is:

High level gentamicin resistance

In order to speciate a swarming Proteus organism found on an eosin methylene blue agar plate, the BEST approach would be to:

determine Indole production, phenylalanine and urease activity

The distinctly large, spreading mucoid colonies seen on blood agar in the upper left image, and the display of lactose fermentation on MacConkey agar in the upper right image provide for a presumptive identification. This species is most commonly recovered from respiratory specimens of patients with pneumonia. Observing a weak reaction for urea, and strong reactions for citrate and Voges Proskauer confirm the presumptive identification. From the multiple choices, select the name of the isolate presented in this exercise.

Klebsiella pneumonia

Illustrated in this photograph is a sulfide indole motility (SIM) tube (left) and an esculin hydrolysis slant (right) after inoculation with an unknown gram positive bacillus and incubation at 30 degrees C for 24 hours. Based on the reactions observed, the most likely identification is:

Listeria monocytogenes

Illustrated in these paired photomicrographs are acid fast stains of tissue sections of colon obtained from an AIDS patient with chronic diarrhea, illustrating a heavy infiltration with acid-fast bacilli (upper image), literally engorging the submucous macrophages (lower image). The Mycobacterium species most commonly associated with this infection is:

Mycobacterium avium intracellulare complex

Illustrated in this photograph are two Middlebrook 7H-11 plates incubated at 35 degrees C, on which are growing colonies of an unknown Mycobacterium species. The plate on the left was incubated in the dark; the plate at the right had been exposed to light for 24 hours. The most likely identification is:

Mycobacterium kansasii

Illustrated in the top image are 10 day old rough, buff, gray-white colonies growing on Middlebrook 7H11 agar. These colonies are commonly recovered from expectorated or induced sputum specimens obtained from patients with signs and symptoms of pneumonia. The appearance of these colonies provide for a presumptive identification, supported by the positive yellow-pigmented niacin reaction seen in the reagent tube in the lower photograph. From these observations, select from the multiple choices the presumptive identification of this isolate.

Mycobacterium tuberculosis

The skin infection of the foot of a farmer as illustrated in the upper photograph was caused in a farmer when walking barefoot in soil contaminated with a filariform larva. Based on the morphology of the 50 um in diameter ovum (lower image), select from the question/answer list the species that is the presumptive cause of the infection.

Necator americanus

Small intracellular gram-negative cocci were observed in a centrifuged spinal fluid sediment as presented in the upper photomicrograph. A clinical diagnosis of meningitis was suspected. Yellow-gray colonies after 24-hour incubation had been observed on blood agar. Based on the carbohydrate utilization tube reactions observed in the lower photograph, select from the multiple choices the presumptive identification of this isolate.

Neiserria meningitidis

The bacterial species shown in this composite photograph of a chocolate agar plate and accompanying gram stain, recovered from an autopsy blood culture of a patient dying with Waterhouse Friderichsen syndrome is most likely

Neisseria meningitidis

The colonies illustrated in the composite blood agar/MacConkey agar to the left were recovered from an inflammatory infection of the oral cavity of a 16-year-old student. The colonies on both agar plates incubated anaerobically are small, entire, and smooth with a light gray-yellow pigmentation. Small gram-negative rods arranged singly and in loose clusters had been observed microscopically in a gram-stained preparation. Spot indole and lipase reactions are positive. Note in the image to the right the alk/alk non-fermentative carbohydrate reaction on Kligler Iron agar, with lack of fermentation of the sugars presented in the tubes to the right (asaccharolytic). Select from the multiple choices the name of this anaerobic, asaccharolytic, gram-negative isolate.

Porphyromonas asaccharolytica

Westgard multi-rule assessments are DIRECTLY applied to evaluate what?

Quality control results

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 37 degrees C. In the photomicrograph, clusters of gram-positive cocci were observed microscopically in a gram stain prepared from one of the colonies. The coagulase reactions are pictured in the lower images. With these observations, select the name of this isolate from the multiple choices as listed.

Staphylococcus aureus

This isolate is a catalase negative, gram positive coccus on sheep blood agar. The P disk has 5 ug of optochin and the zone around it is 16 mm. It has been streaked perpendicular to a beta lysine-producing Staphylococcus aureus. The presumptive identification is:

Streptococcus pneumoniae

The colonies growing on Middlebrook agar shown in the upper left photograph were recovered after 5 days incubation from an aspirate of a superficial skin infection. Gram stain revealed branching bacilli as seen in the lower image. These were non-acid fast. Illustrated in the upper right photograph are colonies growing on casein medium demonstrating hydrolysis. The presumptive identification is:

Streptomyces species

Which of the following does not pose a significant risk of transmitting bloodborne pathogens?

Sweat

What is the primary target of HIV?

T-helper cells

Any laboratory that analyzes microbes or refers specimens that have the potential to contain microbial agents or toxins is a sentinel laboratory.

True

The red ring at the top of the media in this tube indicates a positive indole reaction. The precursor substance in the medium from which the indole is produced is:

Tryptophan

Compared to blood agar media, chocolate blood agar FAVORS the growth of which organisms?

more fastidious bacteria