Best site for collection of specimen for N. meningitides -
Ans. is 'c* i.e.. Nasopharyngeal swab o Best site for specimen collection for meningococci For cases - CSF (by lumbar puncture)For carriers - Nasopharyngeal swabo As CSF is not there in options, examiner is, most probably, asking about specimen in carrier.Laboratory diagnosis of meningococcal infectiono SpecimensCSF - Divided into three portions :o One portion is centrifuged and Gram stained smears are prepared from the deposito The second portion is inoculated on blood agar or chocolate agar plates,o The third portion of CSF is incubated overnight and than subcultured on chocolate agar. Blood - for culture in patients with meningococcemia and early meningitis.Nasopharyngeal swab - for carriersPetechial lesions - In cases of meningococcemia.Autopsy specimens - from meninges, lateral ventricle, surface of brain or spinal cord,o Smear will showGram negative diplococci inside the polymorphs but often extracellularly also.They are arranged in pairs, with the adjacent sides flattened.Capsulatednonmotileo Transport medium - Stuart's mediumo CultureBlood agar, chocolate agar and Muller-Hinton starch casein hydrolysate agar are the media commonly used for culturing meningococci.Modified Thayer - Martin (with vancomycin, colistin and nystatin) is a useful selective medium,o SerologyAntibodies to meningococcal polysaccharides can be measured by latex agglutination or hemagglutination tests or by their bactericidal activity.
Oral swab
Nasal swab
Nasopharyngeal swab
Skin lesions
Bacteria