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MLT-RTI
Microbiology
| Question | Answer |
|---|---|
| What is purpose of sputum as a specimen? | for diagnosis of lower respiratory tract infections |
| What are the common pathogens found in lower respiratory tract infection? | 1.Streptococcus penumoniae 2.Haemophilius influenzae 3.Mycobacterium tuberculosis |
| What is the purpose of throat swab? | for diagnosis of upper respiratory tract infections |
| What are the common pathogens found in upper respiratory tract infect? | 1.Streptococcus pyogenes 2.Corynebacterium diphtheriae 3.Candida albicans 4.Bordetella pertussis |
| What is the macroscopic appearance of sputum? | 1.mucous 2.purulent 3.mucopurulent 4.bloody |
| What is used to digest mucus in sputum? | sputolysin (N-acetyl-L-cysteine) |
| What is the function of chocolate agar? | 1.a blood agar, but with RBC have been lysed by slowly heating to 80°C 2.for growing fastidious respiratory bacteria, such as Haemophilus influenzae and Neisseria meningitidis. |
| What is the function of MacConky agar? | 1. selectively isolate Gram-negative and enteric (normally found in the intestinal tract) bacilli 2. differentiate them based on lactose fermentation 3.no growth of Gram-positive bacteria and fastidious Gram-negative bacteria |
| What is blood agar? | 1.an enriched, bacterial growth medium. Fastidious organisms, such as streptococci 2.5% sheep blood 3.contains X factor(Hemin) |
| For sputum, first do ________ then culture ? | Direct Gram smear stain |
| For throat swab, direct culture on _____ is enough. | Blood Agar, incubate at 37C in 5% of CO 2 |
| What is morphology of Streptococcus pneumoniae? | 1.mucoid 2.umbilicated 3.alpha hemolytic 4.Optochin sensitive |
| What is the gram stain observation of Streptococcus pneumoniae? | 1.Gram positive cocci 2.In pair |
| What the gram stain observation for Streptococcus pyogenes? | 1.Gram positive cocci 2.In chain |
| What is the morphology of Streptococcus pyogenes? | 1.beta heamolytic 2.bacitracin sensitive |
| What is the gram statin observation for Heamophilius influenzae? | 1.Gram negative coccobacilli |
| What makes Chocolate agar so suitable for Haemophilius influenzae? | Chocolate agar has: 1.X factor: Hemin 2.V factor: NAD(Vitamin B) |
| What is the gram stain observation for Klebsiella species? | 1.Gram negative rod 2.mucoid |
| What is the observation of Klebsiella spp from MacConky agar? | 1.Pink 2.Lactose fermenter |
| What is the Causative agent of whooping cough? | Bordetella pertussis |
| What is the gram stain observation for Bordetella pertussis? | Gram negative coccobacilli |
| Is Bordetella pertussis obligate aerobe? | Yes |
| What are the special media for Bordetella pertussis? | 1.Bordet-Gengou (potato-glycerol blood agar) 2.Regan-Lowe agar (charcoal agar + 10% horse blood + cephalexin) |
| What is the growth condition for Bordetella pertussis? | 35°C, CO2 with excess moisture, 3-4 days |
| What is the confirmatory ID test for Bordetella pertussis | Antibody agglutination |
| What is the Causative agent of diphtheria? | Corynebacterium diphtheriae |
| What is the gram stain observation of Corynebacterium diphtheriae? | 1.Gram positive short rods 2. Chinese character, "八" |
| Is Corynebacterium diphtheriae facultative anaerobes? | Yes |
| What are the specimen for Bordetella pertussis? | 1.pernasal nasopharyngeal swabs collected in charcoal transport medium 2.cough plate |
| What is the specimen for Corynebacterium diphtheriae? | Throat swab |
| What can be observed from blood agar of Corynebacterium diphtheriae? | medium size, greyish, circular, convex |
| What is the special stain for corynebacterium diphtheriae? | Albert's stain |
| What is Albert's stain about? | 1.a differential stain 2.staining the volutin granules 3.green colored, rod shaped |
| Corynebacterium diphtheriae is catalase ___1____ and oxidase ___2____. | 1.positive 2.negative |
| What can be observed from Ziehl-Neelsen stain on direct smear of Mycobacterium tuberculosis? | red bacilli, rod shape |
| What can be observed from Auramine O stain on direct smear of Mycobacterium tuberculosis? | yellow fluorescence, rod shape |
| What is the purpose of using NaOH to pretreat the MTB specimen? | 1. decontamination 2. NaOH can remove normal flora |
| What is the culture medium for MTB? | Lowenstein-Jensen medium |
| What can be observed from Lowenstein-Jensen medium of MTB? | buff-coloured & rough colonies |
| What is the culture condition of MTB on LJ medium? | Incubate 37°C for 6-8 weeks |