Micro Quiz 3 (GNC, GPR, etc.)

Question 1

Neisseria species

Answer 1

Gram neg diplococci, capsules found on pathogenic species

Aerobic/microaerophilic, all are oxidase pos and catalase pos

Question 2

Neisseria meningitidis (meningicoccal disease)

Answer 2

Medical emergency, transmitted by secretions/droplets

Fever, sore throat, severe headache, stiff neck, convusions, petechiae (blockage of blood vessels)

Question 3

How to differentiate pathogenic vs nonpathogenic Neisseria?

Answer 3

By colony morphology, primary isolatin site, and what sugars they can use
Group 1 = Traditional pathogens
Group 2 = Neisseria spp. that can grow on selective media (MTM)
Group 3 = Neisseria spp. that cannot grow on selective media (MTM)

Question 4

Moraxella catarrhalis

Answer 4

Opportunistic pathogen of respiratory tract, “hockey puck” test, grows well at 28C, GNC
Asacchrolytic, Butyrate esterase pos

Question 5

Acinetobacter spp.

Answer 5

GNC, Oxidase neg*, catalase pos, aerobe, can grow on MAC

Question 6

Collection of samples for pathogenic Neisseria

Answer 6

Sensitive to drying and extreme temps
CSF, blood, and nasopharyngeal samples should be spun
Nasopharyngeal swab immediately plated on JEMBEC, use Dacron swab not cotton (need charcol in media if using cotton), JEMBEC plated incubated ASAP for 72 hrs at 37C

Question 7

Bacillus spp.

Answer 7

Widely distributed in nature, forms endospores, catalase pos

Question 8

How do you rule out Bacillus anthracis?

Answer 8

B. anthracis is:
Large, Gram pos rod, aerobic, fast grower, “ground glass” colonies, non-hemolytyic, non-motile
Send to reference lab

Question 9

Bacillys anthracis

Answer 9

Spores, GPR, “box car” under microscope, “ground glass” colonies, non-hemolytic, edges not regular, sticky
Can be decolorized more easily when culture is old
Can be in livestock, passed by contact with wool/hide/skin

Question 10

Bacillus cereus

Answer 10

GPR “box car” under microscope, beta hemolytic, motile, not as sticky
Causes food poisoning, can be killed by cooking food properly

Question 11

Corynebacterium spp.

Answer 11

Form shapes on Gram stain, GPR, most are normal flora

Question 12

Corynebacteria diptheriae

Answer 12

GPR, diptheria toxin can cause respiratory (pseudomembrane in throat, cardiac failure) or cutaneous infection (ulcers)
Selective media = Tinsdale agar, grows black colonies
Grow in Loeffler’s serum, stain w/ methylene blue, reveal purple metachromatic granules

Question 13

Erysipelothrix rhusipathiae

Answer 13

GPR, catalase neg, no spores, H2S on TSI, “brush like pattern” in agar stabs at RT
Red skin infections, handling animals

Question 14

Lactobacillus spp.

Answer 14

Normal flora, alpha hemolysis, catalase neg, motility neg, no spores
Produce lactic acid, helps keep muscosa too acidic for pathogens, used in probiotics

Question 15

Bacterial vaginosis

Answer 15

Vagina becomes neutral/basic enough for other flora to create infection
Diagnose with Gram stain of vaginal discharge (clue cell), appearance, smell (add 10% KOH), lower pH
Can cause complications in pregnancy (preterm labor, stillbirth)

Question 16

Listeria monocytogenes

Answer 16

Intracellular GPR, no spores, beta hemolysis, can grow at 4C
Catalase pos, “tumbling” motility at RT, “umbrella” motility in agar, facultative anaerobic

Question 17

3 types of Reproductive Tract infection

Answer 17

Endogenous = overgrowth of normal flora
Iatrogenic = introduced by medical procedure
STD = introduced by intercourse

Question 18

Bacterial (curable) STDs

Answer 18

Syphilis, chancroid, gonorrhea, chlamydia, trichomoniasis

Question 19

Ulcerative bacterial STDs

Answer 19

Syphilis, chancroid

Question 20

Non-ulcerative bacterial STDs

Answer 20

Gonorrhea, chlamydia, trichomoniasis

Question 21

Chlamydia

Answer 21

Gram neg, non-motile, obligate intracellular, no cell wall
Women: asymptomatic, PID, endometritis, urethritis/vaginitis
Men: urethritis, procititis, epididymitis
Neonates: conjunctivits, pneumonitis, genital infection

Question 22

Chlamydia life cycle

Answer 22

Elementary bodies are infectious, endocytosed by host cell, reorganize into reticulate body, multiply/divide to form inculsion, form elementary bodies, lyse host cell and spread

Question 23

Chlamydia collection and testing

Answer 23

Transport on ice, urine or swab

Culture used legal issues, culture confirms other tests

Question 24

Gonorrhea (Neisseria gonorrhoeae)

Answer 24

Causes urethritis, cervicitis, conjunctivits in neonate, PID, arthritis

Question 25

Gonorrhea collection and testing

Answer 25

Collect on Stuart’s or Amie’s charcol medium
Male: if any intracellular diplococci seen, no culture needed
Female: Gram stain not diagnostic, use MTM (Modified Thayer-Martin), NYC, JEMBEC

Question 26

Trichomoniasis

Answer 26

Causes urethral discharge, vaginitis
Swab = goes into saline, then wet mount
Urine = sediment make wet mount
Usually rapid test done

Question 27

Syphilis

Answer 27

Spirochete, can’t culture in vitro
Through wound or mucous membrane, sex, mother to infant
Replicates/disseminates in blood and lymphatics
Multiple stages of disease

Question 28

Syphilis testing/diagnosis

Answer 28

Microscopy only possible in primary stage, lessions present
Start w/ non-treponemal (cardiolipin non-specific ABs) tests, then test w/ treponemal
Non-treponemal will decline w/ treatment, treponemal won’t