MICRO Respiratory/ Genital Flashcards
Normal flora of the Upper Resp Tract
- alpha and non-hem Streptococci
- Haemophilus sp
- Coryneforms/ diphtheroids
- Staphylococcus sp
- Micrococcus sp
- Anaerobes
- Enterobacteriaceae
Only 10-20% of all resp tract infections can be treated by antibiotics. Why ?
Viruses cause >80% of acute upper resp tract infections
Pathogens of the mouth
- Candida sp
- S. pyogenes (if in wound)
- Treponema
Define Thrush
candidiasis in mouth characterized by white patches of exudate on an acutely inflamed mucosa
Pathogens of the nose
- S. aureus
- S. pyogenes (if pure)
Pathogens of the throat
- S. pyogenes
- Corynebacterium dipththeriae (toxigenic)
- N. gonorrhoeae
- H. influenzae
the lower resp tract should have what organisms in healthy individuals ?
NONE; LRT should be sterile in healthy individuals
T or F: lower resp specimens are often contaminated
TRUE; organisms from mouth/ throat often contaminate lower resp specimens
What maintains the pH of the vagina ?
- Lactobacillus acidophilus
- produces lactic acid from glycogen
NOTE: at pH of 4.4 to 4.6
Normal pH of the vagina. Why is that ?
acidic; 4.4 to 4.6
- inhibits growth of E. coli (Enterobacteriaceae)
Which organisms can grow despite acidic pH of vagina ?
- Anaerobes
- Enterococci
- C. albicans
The cervix is generally sterile because of its __.
The cervix is generally sterile because of its ALKALINE pH.
Normal Flora of Genital Tract
- non-hem Streptococci
- CNS
- viridans group Strep
- Diphteroids/ coryneforms
- Lactobacillus sp
- Neisseria sp
NOTE: similar to urine/ skin
Pathogens of the Genital Tract
- N. gonorrhoeae
- S. aureus
- P. aeruginosa
- Haemophilus ducreyii
- Candida sp
- Group A & B Strep
- Chlamydia trachomatis
- Trichomonas vaginalis
- Gardnerella vaginalis
- Treponema pallidum
Define Bacterial Vaginosis
imbalance of normal flora; decreased Lacto, increased Gardnerella sp./ anaerobes
Define Cervicitis. What is it caused by ?
- inflammation of the cervix/ external uterine opening
- Neisseria gonorrhoeae, anaerobic organisms, Chlamydia or Herpes virus
Define Epididymitis. What causes it ?
- inflammation of the epididymis/ coiled duct (on anterior surface of testes)
- blockage due to complication with N. gonorrhoeae = sterility in males
Define Genital Ulcers
ulcers caused by Treponema pallidum, Haemophilus ducreyii, Chlamydia trachomatis
Define Non-gonococcal urethritis
- usually in men
- Chlamydia, Trichomonas, Herpes, Ureaplasma urealyticum
Which of the following statements is / are true of Corynebacterium diphtheriae?
Select all that apply:
a.
Epsilon-test is used to test for toxin production
b.
All strains of Corynebacterium diphtheriae are toxigenic
c.
Can be part of normal flora
d.
Colonies look dry on BAP
c.
Can be part of normal flora
d.
Colonies look dry on BAP
NOTE: ELEK test is used to test for toxin production
Which of the following media is suitable for primary isolation of Legionella sp?
a.
Chocolate agar
b.
Regan Lowe agar
c.
Buffered charcoal yeast extract agar
d.
Lowenstein Jensen agar
c.
Buffered charcoal yeast extract agar
Which of the following organism(s) is / are included in the Pseudomonas fluorescent group?
Select all that apply:
a.
Pseudomonas putida
b.
Pseudomonas stutzeri
c.
Pseudomonas aeruginosa
d.
Pseudomonas diminuta
a.
Pseudomonas putida
c.
Pseudomonas aeruginosa
Which of the following statements best describes Streptococcus pneumoniae?
a.
Bile soluble, catalase positive, optochin resistant
b.
Bile soluble, catalase negative, optochin sensitive
c.
Bile soluble, catalase positive, optochin sensitive
d.
Bile soluble, catalase negative, optochin resistant
b.
Bile soluble, catalase negative, optochin sensitive
Col morph: M. catarrhalis
gy
Col morph: Viridans group Strep
fgn
Col morph: S. pneumoniae
wet α
Which of the following sputum specimens can be rejected based on a poor Q-score?
a.
Specimen is the 3rd in a series with two prior unacceptable
b.
Patient has 2+ RBC present
c.
Patient has decreased neutrophils in their blood
d.
Patient is immunosuppressed
b.
Patient has 2+ RBC present
Which of the following specimens is best for isolation of Bordetella pertussis?
a.
“Cough” plate
b.
Expectorated sputum
c.
Pleural fluid
d.
Nasopharyngeal swab
d.
Nasopharyngeal swab
Which of the following respiratory pathogens require manual susceptibility testing?
Select all that apply:
a.
Haemophilus influenzae
b.
Staphylococcus aureus
c.
Streptococcus pneumoniae
d.
Moraxella catarrhalis
a.
Haemophilus influenzae
- fastidious
c.
Streptococcus pneumoniae
- wet consistency interferes with instrument
Which of the following characteristic(s) describes both Haemophilus influenzae and Bordetella pertussis?
Select all that apply:
a.
Infect animals of many species
b.
Cause invasive disease
c.
Grow well on simple media
d.
Small gram negative bacilli
d.
Small gram negative bacilli
Which of the following organism and test result pairings is correct?
a.
Neisseria mucosa: oxidase negative / butyrate esterase positive
b.
Neisseria meningitidis: oxidase positive / gram negative coccobacilli
c.
Neisseria gonorrhoeae: oxidase positive / ONPG positive
d.
Moraxella catarrhalis: oxidase positive / DNase positive
d.
Moraxella catarrhalis: oxidase positive / DNase positive
Which of the following organisms is a pathogen of the oropharynx?
a.
Staphylococcus aureus
b.
Streptococcus pyogenes
c.
Streptococcus viridans
d.
Streptococcus pneumoniae
b.
Streptococcus pyogenes
- strep throat
Which of the following organisms play an important role in protecting the female genital tract against pathogens?
a.
Diphtheroids
b.
Gardnerella vaginalis
c.
Escherichia coli
d.
Lactobacilli
d.
Lactobacilli
What is the most common vaginal infection in women of childbearing age?
a.
Neisseria gonorrhoeae
b.
Trichomonas vaginalis
c.
Bacterial vaginosis
d.
Chlamydia trachomatis
c.
Bacterial vaginosis
Which of the following statements is true about Neisseria gonorrhoeae?
a.
Serologic diagnosis is more reliable than culture
b.
Penicillins are no longer recommended for treatment
c.
Bacteremia is common
d.
Men are frequently asymptomatic carriers
b.
Penicillins are no longer recommended for treatment
Which of the following specimens is acceptable for Treponema pallidum identification?
a.
Lesion swab
b.
Cervical swab
c.
Urethral swab
d.
Urine
a.
Lesion swab
Which of the following direct smear results from a vaginal specimen would be reported as NEGATIVE for bacterial vaginosis?
a.
4+ WBC 2+ EPI 4+ GNB* 4+ GPBL
b.
4+ WBC 2+ EPI 4+ GPCCL 4+ GPBL
c.
4+ WBC 2+ EPI NBS
d.
4+ WBC 2+ EPI 4+ GNB* 4+ GNB colif
b.
4+ WBC 2+ EPI 4+ GPCCL 4+ GPBL
The following results are recorded for a vaginal direct smear:
1+ WBC
4+ EPI
3+ GPBL
1+ GPB dips
1+ GNDC
1+ GPC cl
1+ GNB *
a.
Negative for bacterial vaginosis
b.
Indeterminate for bacterial vaginosis
c.
Positive for bacterial vaginosis
d.
Positive for N. gonorrhoeae
a.
Negative for bacterial vaginosis
- No Gardnerella (GVB) or MOB
Which of the following reagents is used for the whiff test for bacterial vaginosis?
a.
H2O2
b.
MgO2
c.
KOH
d.
HCl
c.
KOH
The following results are recorded from vaginal direct smears. Which of the following results require further work up?
Select all that apply:
a.
4+ WBC 2+ EPI 4+ GNB* 4+ GPBL
b.
4+ WBC 2+ EPI 4+GPCCL
c.
4+ WBC 2+ EPI 4+GNB colif I/E
d.
4+ WBC 2+ EPI 4+ GPBL
b.
4+ WBC 2+ EPI 4+GPCCL
c.
4+ WBC 2+ EPI 4+GNB colif I/E
Which of the following characteristics is true of pathogenic Neisseria?
Select all that apply:
a.
35-37°C for growth
b.
Fastidious growth requirements
c.
Wetgy / shgy colonial morphology
d.
Grows in O2 and CO2
a.
35-37°C for growth
b.
Fastidious growth requirements
c.
Wetgy / shgy colonial morphology
ALA Test Principle and possible results ?
ALA = Delta-aminolevulinic acid = tests organism’s ability to synthesize their own hemin (X factor) from an ALA supply
Results:
Red fluorescence (+) = no hemin requirement/ produces own X factor
No fluorescence (-) = requires exogenous hemin for growth/ does not produce X factor
What is the principle of the oxidase test ? What is a positive result ?
Principle: TMPD (tetramethyl-p-phenylene diamine) reagent interacts with cytochrome c oxidase in electron transport chain
Positive (+): non-fermenters produces dark purple indophenol
Principle of Plate Bile Solubility. What is a positive result ?
Principle: presence of bile salts accelerate activity of autolytic enzyme
Positive: flattened/ dissolved colonies after 15 min
Media for C. diphtheriae
- Loeffler’s media
- Modified Tinsdale
Media for Bordetella pertussis (3)
Charcoal
Reagan-Lowe agar
Bordet-Gengou agar
Principle of ELEK test. What is a positive result ?
Principle:
Differentiates atoxigenic and toxin-producing C. diphtheriae
Positive:
Neutralization b/w toxin + antitoxin-impregnated filter paper= precipitation lines (X)
Fluorescent stain for Mycobacteria tuberculosis
Auramine-rhodamine stain
Why do acid-fast organisms stain differently using Ziehl-Neelsten stain ?
- Since acid-fast properties of mycolic acids do not bind simple stains:
Use Ziehl-Neelsten= carbol fuchsin (basic) + acid alcohol decolorizer + methylene blue counterstain
- LIPOID CAPSULE stains with carbol-fuchsin and resists decolorization by acid alcohol
