Micro Quiz 3 (GNC, GPR, etc.) Flashcards
Neisseria species
Gram neg diplococci, capsules found on pathogenic species
Aerobic/microaerophilic, all are oxidase pos and catalase pos
Neisseria meningitidis (meningicoccal disease)
Medical emergency, transmitted by secretions/droplets
Fever, sore throat, severe headache, stiff neck, convusions, petechiae (blockage of blood vessels)
How to differentiate pathogenic vs nonpathogenic Neisseria?
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)
Moraxella catarrhalis
Opportunistic pathogen of respiratory tract, “hockey puck” test, grows well at 28C, GNC
Asacchrolytic, Butyrate esterase pos
Acinetobacter spp.
GNC, Oxidase neg*, catalase pos, aerobe, can grow on MAC
Collection of samples for pathogenic Neisseria
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
Bacillus spp.
Widely distributed in nature, forms endospores, catalase pos
How do you rule out Bacillus anthracis?
B. anthracis is:
Large, Gram pos rod, aerobic, fast grower, “ground glass” colonies, non-hemolytyic, non-motile
Send to reference lab
Bacillys anthracis
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
Bacillus cereus
GPR “box car” under microscope, beta hemolytic, motile, not as sticky
Causes food poisoning, can be killed by cooking food properly
Corynebacterium spp.
Form shapes on Gram stain, GPR, most are normal flora
Corynebacteria diptheriae
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
Erysipelothrix rhusipathiae
GPR, catalase neg, no spores, H2S on TSI, “brush like pattern” in agar stabs at RT
Red skin infections, handling animals
Lactobacillus spp.
Normal flora, alpha hemolysis, catalase neg, motility neg, no spores
Produce lactic acid, helps keep muscosa too acidic for pathogens, used in probiotics
Bacterial vaginosis
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)
Listeria monocytogenes
Intracellular GPR, no spores, beta hemolysis, can grow at 4C
Catalase pos, “tumbling” motility at RT, “umbrella” motility in agar, facultative anaerobic
3 types of Reproductive Tract infection
Endogenous = overgrowth of normal flora Iatrogenic = introduced by medical procedure STD = introduced by intercourse
Bacterial (curable) STDs
Syphilis, chancroid, gonorrhea, chlamydia, trichomoniasis
Ulcerative bacterial STDs
Syphilis, chancroid
Non-ulcerative bacterial STDs
Gonorrhea, chlamydia, trichomoniasis
Chlamydia
Gram neg, non-motile, obligate intracellular, no cell wall
Women: asymptomatic, PID, endometritis, urethritis/vaginitis
Men: urethritis, procititis, epididymitis
Neonates: conjunctivits, pneumonitis, genital infection
Chlamydia life cycle
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
Chlamydia collection and testing
Transport on ice, urine or swab
Culture used legal issues, culture confirms other tests
Gonorrhea (Neisseria gonorrhoeae)
Causes urethritis, cervicitis, conjunctivits in neonate, PID, arthritis
Gonorrhea collection and testing
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
Trichomoniasis
Causes urethral discharge, vaginitis
Swab = goes into saline, then wet mount
Urine = sediment make wet mount
Usually rapid test done
Syphilis
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
Syphilis testing/diagnosis
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
