Week 1 - Urines

What is the #1 cause of UTI’s?

E. coli

What species are considered skin contaminants in urine?

1. CNS

2. Diphtheroids

3. Lactobacillus

What organism is usually associated with disease in patients who have recently undergone UTI surgery, indwelling catheterization, or patients with chronic urinary tract disease?

S. epidermidis

Should you perform AST on S. aureus?

Yes because patterns vary and some are MRSA.

Should you perform AST on S. saprophyticus?

No because it’s susceptible to routinely used antibiotics

Should you perform AST on S. epidermidis?

No because it is likely skin contamination. Only performed on request.

Should you perform AST on Enterococcus?

Yes, because some are Ampicillin or Vancomycin resistant

Should you perform AST on Group A & B Strep?

No, because they are susceptible to Penicillin.

What is the only catalase-positive, GPR found in the genital tract? Is it clinically significant?

1. Lactobacillus

2. No. Normal flora

What does a purple slant, purple butt mean for a Lysine test?

Decarboxylase positive

What does a purple slant, yellow butt mean for a Lysine test?

Decarboxylase negative

What does a red slant, yellow butt mean for a Lysine test?

Deaminase +

What does a purple slant, black butt mean for a Lysine test?

Decarboxylase neg, H2S +

What is considered normal intestinal stool flora?

1. Enteric GNR

2. Anaerobes

3. Enterococcus

4. Streptococcus

5. Other g+’s

What three sugars are included in Hektoen media?

1. Lactose

2. Sucrose

3. Salicin

Is E. coli O157:H7 a lactose fermenter or a non-lactose fermenter?

Non-lactose fermenter

What is the TSI slant of Salmonella?

K/A or K/Ag and H2S

What is the motility, Lysine, and Urea tests for Salmonella?

1. Motile

2. LDC+ with H2S

3. Urea-

How can Shigella and Salmonella be differentiated from each other?

Shigella has green colonies while Salmonella has green colonies with black centers.

What two organisms look exactly the same? On which media can they be mistaken for each other? What is the shared morphology they both have?

1. Proteus and Salmonella

2. Hektoen agar and MacConkey

3. Colorless colonies on MAC and green with black centers on HE

What media should you use to differentiate Proteus from Salmonella? How can you tell them apart?

1. XLD agar

2. Proteus colonies will be yellow with black and Salmonella will be red with black.

What is unique about Salmonella paratyphi?

It’s H2S negative

What are the catalase, motility, VP, and BE results for Listeria monocytogenes?

1. Catalase: +

2. Motility: + (umbrella)

3. VP: +

4. BE: +

What can Listeria be mistaken for?

cocci

What antibiotic is K. pneumoniae usually resistant to?

Ampicillin

What is Enterobacter cloacae usually resistant to?

Ampicillin and Cephazolin

What is P. mirabilis usually resistant to?

Nitrofurantoin and Tetracy

What is P. aeruginosa susceptible to?

Resistant to most drugs except for Aminoglycosides

What is S. maltophilia usually susceptible to?

1. Trimethoprim

2. Sulfamethoxazole

What is the relationship between KB zone of inhibition and MIC value?

Inversely proportional

What three antibiotics interfere with protein synthesis?

1. Rifampin

2. Quinolones

3. Metranidazole

What drugs affect cell wall integrity?

1. Beta-lactams

2. Vancomycin

What drugs inhibit essential metabolites?

1. Sulfonamides

2. Trimethoprim

What drug affects cell membrane structure and function?

Polymyxins.

What is the diagnostic criteria for Bacterial Vaginosis?

1. pH > 4.5

2. Clue cells

3. Milky, homogenous discharge

4. Odor

What three drugs do you use to treat BV?

1. Metranidazole

2. Clindamycin

3. Tinidazole

What bacteria is associated with appendicitis-like symptoms?

Yersinia enterocolitica

What is the most common cause of gastroenteritis worldwise?

Campylobacter jejuni

What organism has unique growth conditions compared to the rest of the enterics, and what are they?

1. Campylobacter jejuni

2. 42 degrees Celsius, microaerophilic

Loss of bacterial vaginosis leads to a rise of what four bacteria?

1. Gardnerella vaginalis

2. Mobiluncis

3. Bacterioides

4. Prevotella

What five agents can cause cervicitis?

1. Neisseria gonorrhea

2. Chlamydia trachomatis

3. Mycoplasma genitalium

4. Herpes Virus

5. HPV

What treatment is used for Gonorrhea? What extra treatment needs to be included?

1. Ceftriaxone

2. You also need to treat a potential Chlamydia coinfection with a separate drug because this organism lacks a cell wall. Since cephalosporins target the cell wall, this won’t kill Chlamydia too. Azithromycin should treat Chlamydia

What media is used to isolate gonococci?

1. Thayer-Martin medium

2. NYC (isolates mycoplasms too)

What media can be used to isolate GBS?

1. Todd-Hewitt

2. LIM Broth