Microbiology Solo 4 Kahoot and Study Questions

The majority of all Enterobacteriales are positive for what test?

Nitrate reductase

Which sugar is not a part of the TSIA sugar fermentation test?

Maltose

Which is used to separate the genus Serratia from the other Enterobacteriales?

Dnase

All Enterobacteriales, except for one, are negative for what biochemical test?

Oxidase

What is the substrate in the indole reaction?

Tryptophan

The end product for ornithine decarboxylase is

Putrescine

If Salmonella species was planted to a TSIA, what would the reaction be?

Unable to see reaction

A/A, Gas in glucose, PD (-), H2S (-), Indole (+), Citrate (+), Ornithine (-), Nonmotile, Lysine (+), Urea (+), Malonate (+)

Klebsiella oxytoca

K/A, Gas in glucose, PD (-), H2S (-), Indole (-), Citrate (-), Ornithine (+), Motile, Lysine (+), VP (+)

Hafnia alvei

A/A, Gas in glucose, PD (-), H2S (-), Indole (+), Citrate (-), Ornithine (-), Motile, Lysine (+)

Escherichia coli

K/A, Gas in glucose, PD (-), H2S (+), Indole (-), Citrate (+), Ornithine (+), Lysine (+), Motile, Malonate (-)

Salmonella species

K/A, Gas in glucose, PD (+), H2S (+), Indole (-), Citrate (-), Ornithine (+), Motile, Lysine (-)

Proteus mirabilis

K/A, Gas in glucose, PD (-), H2S (+), Indole (-), Citrate (+), Ornithine (+), Motile, Lysine (+), Malonate (+)

Arizona hinshawii

K/K, Glucose oxidizer, PD (+), H2S (-), Indole (-), Citrate (+), Lysine (-), Maltose (-), Non-motile, Oxidase (-)

Acinetobacter baumanii

Which pathogenic strain of Escherichia coli contains the strain that can cause Traveler’s Diarrhea?

ETEC

A Yersinia enterocolitica infection may mimic what disease?

Appendicitis

A possible Yersinia pestis is suspected in a case where some hikers came across an aggressive prairie dog. An oxidase and indole was performed on a colony that grew after about two days at room temperature and was negative. What is the next biochemical that should be performed?

Urease

What oxidase positive Enterobacteriales causes a dysentery-like diarrhea?

Plesiomonas shigelloides

Which group of antibiotics would be affected by an Extended Spectrum Beta-Lactamase (ESBL) producer?

Ampicillin, Ceftriaxone, Cefepime

For an H2S producer, on what media would you plant the organism to determine the fermentation or oxidation reactions without the black pigmentation?

O-F media

What genus from the Proteae tribe is known for “swarming” the agar?

Proteus

Case Study 4-1

A 34-year-old female, who underwent kidney transplantation 2 years earlier, presented to the hospital with fever and confusion. Blood cultures obtained on admission were positive with a gram-negative rod. A direct identification strip was inoculated from the blood cultures that was biochemically identified as Shigella spp., with very few positive reactions. The isolate did not type with Shigella antisera. The test was repeated from a colony the next day with the same low number of positive reactions. However, the technologist noticed that the original strip had been incubating on the counter was now positive for urease, indole, and a number of sugar fermentation reactions. Adding the additional biochemical reactions, the organism was correctly identified as Yersinia enterocolitica. When the patient was questioned, she admitted that she had been eating unpasteurized imported goat cheese.

Refer to Case Study 4-1

Why did the reactions change in the second incubation period?

The reactions likely changed in the second period because Yersinia enterocolitica is a slow growing organism and grows best at 25 degrees Celsius. Since the biochemical test strip was left out on the counter, the organism was at an optimal temperature for growth which likely allowed the organism to mature and the reactions to become positive

Refer to Case Study 4-1

Had this organism been Yersinia pestis, what reaction(s) would have been different?

Urease and Indole would be negative

Case Study 4-2

A 68-year-old rancher presents to the outpatient clinic with a cheif complaint of abdominal cramps and diarrhea for 2 days. He is diagnosed with viral gastroenteritis and sent home on antidiarrheal medication. Three days later, he returns with complaints of several bloody, liquid stools per day with associated severe abdmonial cramping. He has associated weakness, dissiness on standing, and dyspnea.

He has a past history of renal insufficiency, congestive heart failure (CHF), coronary artery disease (CAD), peripheral artery disease (PAD), and chronic obstructive pulmonary disease (COPD). In addition to several other prescription medications, he takes 40 mg of prednisone daily, because he was diagnosed with polymylagia rheumatica 1 month ago

He denies any travel history of known ill contacts. He continues to operate his own ranch and often butchers his cattle for his own use. He has not eaten at any restaurants; however, when asked about his eating habits, he admits to eating raw hamburger almost daily. He explains that he prepares it according to his native Lebanese customs, and he belives that it is safe to do this because the meat comes from his own ranch and therefore is not "contaminated" in a packing plant.

He is found to be febrile and dehydrated and is admitted to the hospital for intravenous (IV) hydration and further investigation. Empirically, he is started on IV tigecycline. Given his previous vascular disease history, ischemic colitis is suspected.

Refer to Case Study 4-2

What is most likely the route of transmission, or source, of the patient’s infection?

The most likely source of the infection is the patient eating raw hamburger meat

Refer to Case Study 4-2

What is the most etiologic agent of this infection?

Serologic Escherichia coli (STEC)/Enterohemorrhagic Escherichia coli (EHEC), likely E. coli O157:H7

Refer to Case Study 4-2

Describe the spectrum of disease possible with this type of infection due to this etiologic agent

Serotoxigenic Escherichia coli (STEC) can cause hemorrhagic diarrhea, colitis, and Hemolytic Uremia Syndrome (HUS). HUS is associated with a hemolytic anemia and low platelet count, often resulting in kidney failure and deathYEr

All of the following organisms are considered normal intestinal flora except?

Yersinia enterocolitica

Enterobacteriales are typically gram-negative and

Capable of reducing nitrates to nitrites

A patient presents to the physician with pain and frequency of urination. The urine culture reveals a non-lactose fermenting, gram-negative rod with charcteristic “Swarming” on blood agar. The biochemical test that would specifically distinguish this organism from the other Enterobacteriales is

PD and H2S

An Escherichia coli susceptibility was set up with the following results:

Antibiotic	MIC	Interpretation
Ampicillin	>=16	Resistant
Ampicillin/Sulbactam	>=16	Resistant
Cefazolin	>=64	Resistant
Cefepime	16	Resistant
Ceftazidime	32	Resistant
Ceftriaxone	>=64	Resistant
Ertapenem	<=0.5	Susceptible
Levofloxacin	2	Susceptible
Gentamycin	1	Susceptible
Meropenem	<=0.25	Susceptible
Nitrofurantoin	>=64	Resistant
Piperacillin/Tazobactam	4	Susceptible
Trimethoprim/Sulfamethoxazole	>=320	Resistant

What resistance mechanism, if any, is shown? Explain your answer

It is likely that this strain of Escherichia coli is an Extended Spectrum Beta-Lactamase producer because the organism is showing resistance to Ampicillin, Cefepime, and Ceftriaxone

Which of the following are the third and fourth most common gram-negative bacilli found in clinical specimens?

Acinetobacter species and Stenotrophomonas maltophilia

The primary drug of choice for Stenotrophomonas maltophilia is

Trimethoprim/Sulfamethoxazole

Compare and contrast glucose oxidizers and glucose fermenters

Glucose oxidizers utilize glucose in aerobic environments

Glucose fermenters utilize glucose in both aerobic and anaerobic environments

Identify the genus and species for the following biochemical reactions

K/A, no gas in glucose, PD (+), H2S (-), Indole (+), Citrate (+), Ornithine (-), Motile, Lysin (+), Urea (-)

Providencia stuartii

A/A, gas in glucose, PD (-), H2S (-), Indole (-), Citrate (+), Ornithine (-), Non-motile, Lysine (+), Urea (+), Malonate (-)

Klebsiella pneumoniae

Identify the genus and species for the following biochemical reactions

K/A, gas in glucose, PD (+), H2S (+), Indole (-), Citrate (-), Ornithine (+), Motile, Lysine (-)

Proteus mirabilis

Identify the genus and species for the following biochemical reactions

K/K, glucose oxidizer, PD (+), H2S (-), Indole (-), Citrate (+), Lysine (-), Maltose (-), Non-motile, Oxidase (-)

Acinetobacter Baumannii