Clostridium Cornyebacterium Neiserria Flashcards
(20 cards)
Q. Classify gram +ve rods
Gram +ve rods
Aerobic
Spore forming - Bacillus
Non spore forming
Cornyebacterium
listelia
Anaerobic
Spore forming - Clostridim
Non spore forming
Actinomycetes
Nocardia
Lactobacillus
Q. How will you confirm the toxigenic strain of cornyebacterium diphtheria
Elek’s test:
A rectangular strip of filter paper is soaked with antitoxin and is placed in a media.
The testing strain is inoculated at rt angle of the filter paper and incubated at 37°C for 1-2 days.
Observation
Toxin producing organisms grow, toxin diffuses into midion, meet with antitoxin & produce “line of precipitation” like arrow head pattern.
Lab diagnosis of cornyebacterium diptheria
Specimen: Throat swab underneath membrane.
2 swabs = one for culture, one for smear.
M/E: Grain stained smear
Albert stain.
Metachromatic granules are present.
Bacteria-Bluish green.
Culture:
Loefflor’s serum slope: Enriched media, stained & Albert stain.
Used for primary isolation.
Tellurite blood agar: selective media.
Typical grey-black colonies
org reduces potassium tellurite to tell
Blood agar media; diff strep from pharyngitis
Tinsdala Cystein Sodium Thiosulfate.
Toxigenicity test
In vivo:
Animal pathogenicity test
guinea pig test: to estimate diptheria antitoxin titre in immunized sera
In vitro: Eleks test
Biochemical
Catalase: +Ve
Oxidase = -ve
Urease = -Ve
PCR - for detection of Tox-gene
ELISA
Tissue culture test
CLOSTRIDIUM.
Name the medically imp. clostridia & diseases produced by them.
Clostridium tetany - Tetanus.
Clost. botulinum - Botulism.
Clost. Perfringens: histotoxic & causes gas gangrene.
Clost. septicum: histotoxic & causes Sepsis.
Pathogenesis of tetanus:
Clost. tetany produces tetanospasmin (toxin).
Tetanospasmin is carried intra- axonally to CNS.
In CNS esp. spinal cord, it binds to ganglioside receptors.
Blocks release of inhibitory mediators glycine and gaba at spinal synapses.
Withdrawal of normal inhibitory impulses over lower motor neuron.
Excitatory neurotransmitter gets upper hand
Exaggerated reflex & convulsion
Hyperflexia
Strong muscle spasm & spastic paralysis
I. Management of a case of road traffic accident having tetanus prone injury.
Treatment of tetanus: (ABCD)
Administration of antitoxin (Tetanus Ig) 3000-1000 U in IV.
Debridement of wound to remove FB.
Penicillin within 6 hrs. (Antibiotic).
Muscle relaxant / sedative.
TT booster doses in dangerous wound.
Passive immunity
T Ig & TT at diff sites
Q. Name the bacteria causing food poisoning?
Toxin mediated:
Staph. aureus
Clost. perfringens
Clost. Botulinum
E. coli
Non-Toxin mediated:
Salmonella typhi
Salmonella enteretidis.
Clost. Botulinum
Campylobacter jejuni
Bacillus cereus.
Listeria monocytogenes
- Write the mech. of botulism
Spores survive and germinate in canned anaerobic environment.
↓
Toxin is produced within canned food.
↓
Ingestion of preformed toxin.
↓
Absorption from gut.
↓
Carried via blood to PNS of cranial nerve.
↓
Binds to receptors of presynaptic membrane of motor neuron.
↓
Cleaves the protein involved in Ach release.
↓
Blocks release of Ach.
↓
Lack of muscle contraction.
↓
Flaccid type of paralysis.
Classify gram neg cocci
GRAM NEG COCCI - NEISSERIA
↓
Pathogenic
Neisseria meningitidis
Neisseria gonorrhoeae
Non pathogenic
N. flava
N. subflava
N. sicca
N. pharyngis
Lab diagnosis of clostridium
LAB DIAGNOSIS
Specimen: wound swab
Pus
Tissues from wound.
M/E: Gram positive bacilli are found.
Culture:
Anaerobic conditions:
Robertson cooked meat media
Thioglycolate media
Egg yolk agar.
Biochemical test: Sugar fermentation reaction.
Other tests: Nagler’s test
Give the pathogenesis of clostridial myonecrosis / gangrene
Causal Organisms:
Clostridium perfringens
Clostridium welchii
Clostridium sedematiens
Clostridium septicum
Clostridium histolyticum
Clostridium fallax
Predisposing factors:
Reduced blood supply
Presence of aerobic organisms
Reduced O-R potentials
Pathogenesis:
Spores of clostridium are introduced to the injury. Aerobic organisms multiply, use O2, and produce an anaerobic environment.
Germination of anaerobic organisms. They start to multiply and liberate toxins and enzymes that are lethal, necrotizing, and have hemolytic properties. Destroy muscle fibers and produce gas.
Wounds rapidly increases in size. Toxins & enzymes enter into blood → severe toxaemia → circulatory failure → death.
predisposing factors of Pseudomembranous collitis
Antibiotics.
frequently → Ampicillin
Amoxicillin
Cephalosporin
clondamycin.
Occasionally: Penicillin
Sulfonamides
erythromycin
trimethoprim.
Rarely: Tetracycline
chloramfenicol.
Q. Lab diagnosis of acute gonococcal urethritis in male.
Specimen:
Male: Acute case: Urethral discharge.
Chronic case: Prostatic secretion by prostatic massage.
Female: Endocervical swab (cult & clx).
New Born: Conjunctival swab
M/E: Gram-ve diplococci with polymorphonuclear leukocytes.
Culture: Special media.
Chocolate agar media
Thayer Martin media
Modified New York city media
Inc temp: 37°C.
Inc period: 18-24 hrs.
Env: 5-10% CO₂.
Biochemical test: Oxidase positive.
Ferments glucose.
Serological test: ELISA
DNA probe assay.
Nucleic acid based technique: PCR.
Q. Bacteria causing urethritis (non-gonococcal).
Bacterias
- E. coli
Proteus.
Pseudomonas
Streptococci
Staph. epidermidis, saprophyticus.
Viruses: Adeno virus.
Fungus: Candida albicans.
Parasites = Schistosoma hematobium
Wuchereria brancrofti
Neiserria Meningitidis
A. Bacterial cause of meningitis in diff age groups.
Neonates:
E. coli
Proteus
Group B streptococcus.
listeria monocytogens.
Preschool child:
H. Influenzae
N. Meningitidis.
Strep preumoniae.
M. Tuberculosis
Older child/Adults:
N. meningitidis
Strep pneumoniae.
M. tuberculosis
Q. How will you manage a case of acute gonococcal urethritis:
Drug: Inj. Ceftriaxone IM / Cap. Cefixime or Tab ciprofloxacin.
Both partners should be treated simultaneously.
Barrier method / contraceptives.
Increased water intake.
lab diagnosis of meningitis.
Specimen:
CSF
Blood
Nasopharyngeal swabs
M/E: Uncentrifuged smear TC + DC of WBC
Centrifuged smear gram staining…
Zeihl Neelson staining acid fast
Culture: At 37°C aerobically for 24 hrs.
Blood agar media
Chocolate agar media
Mc Conkey agar media
At 37°C aerobically for 4-6 weeks in Lowen Stein Jensen media
Immunological test:
Detection of bacterial antigens of cryptococcus neoformans from CSF by latex agglutination test
Routine CSF exam –> done
d. Explain the antigenic heterogenicity of Neisseria gonorrhoeae.
There is marked antigenic variation as a result of chromosomal rearrangement in gonococcal pili. More than 100 types are known. Pili is an important virulence factor of N. gonorrhoeae.
Some strains have no pili, so they are not pathogenic.
Gonococci have 3 Outermans proteins as well (Pr.19293).
Protein 2 plays a role in attachment of org and shows antigenicity as well.
- Diff. b/w pyogenic and aseptic meningitis (CSF)
Bacterial
Physical: Pressure: Normal
Colour: Cloudy
Clot: Formed
White cell count: >200 x 10^6/L -> neutrophils
Biochemical: Protein: ↑sed
Glucose: ↓sed
Chloride: slightly ↓sed
Gram stain done: Done
Culture: blood agar +
Mc. Conkey agar media
Viral/aseptic
Normal pressure / elevated
Clear colour
no clot
10 x 10^6/L -> lymphocytes
Protein: ↑sed
Glucose: Normal / bred slightly
Chloride: Normal
Gram stain Not done
Not cultured easily
Tubercular
Physical: Pressure: Normal / Inc.
Colour: Clear / cloudy
Clot: Spider web clot
WBC count: >10 x 10^6/L -> lymphocytes
Biochem: Protein: Inc.
Glucox: Dec.
Chloride: Dec.
M/E: Acid fast staining / Zeihl Nelson
Culture: Lowenstein jensen media
