Gram Stain of Sputum Showing Gram Positive Cocci in Pairs: Possible Organism and Its Details
Gram stain of Sputum Showing Gram-Positive Cocci in Pairs
Gram stain of sputum showing Gram-positive cocci in pairs as shown above image.
Introduction Of Pneumococcus
Pneumococcus or Streptococcus pneumoniae in Gram stain showing Gram-positive diplococci or Gram-positive cocci in pairs as shown above picture.
Scientific classification of Pneumococcus
- Domain: Bacteria
- Phylum: Firmicutes
- Class: Bacilli
- Order: Lactobacillales
- Family: Streptococcaceae
- Genus: Streptococcus
- Species: S. pneumoniae
Binomial name
Streptococcus pneumoniae
It is a Gram-positive elongated coccus usually found in pairs i.e diplococci or lanceolate, alpha-hemolytic on blood agar facultative anaerobic, non-sporulated, non-motile but a capsulated member of the genus Streptococcus. It resides asymptomatically in healthy carriers typically colonizing the respiratory tract, sinuses, and nasal cavity.
Pathogenicity Of Pneumococcus
Pneumococcus is the most common cause of bloodstream infections, pneumonia, meningitis, and middle ear infections ( Otitis media) in young children. Severe infections can occur in the elderly and those already in poor health or immunosuppressed. The risk of infection is increased following splenectomy. In tropical and developing countries, S. pneumoniae is a major pathogen, responsible for acute life-threatening pneumonia and bacteremia in those co-infected with HIV The invasive pneumococcal diseases include bronchitis, rhinitis, acute sinusitis, otitis media, conjunctivitis, meningitis, sepsis, osteomyelitis, septic arthritis, endocarditis, peritonitis, pericarditis, cellulitis, and brain abscess. Childhood pneumonia and serious infections are
in patients with sickle cell disease.
Serotypes: Over 80 capsular serotypes whereas less than 15 serotypes are responsible for most infections.
Laboratory Diagnosis Of Pneumococcus
Specimens: Depending on the site of infection, specimens may include sputum, exudate, blood for culture, and cerebrospinal fluid.
Gram stain of specimen
Gram-positive elongated (lanceolate) diplococci and may show evidence of capsule but no evidence of spore.
Blood agar: Following overnight incubation. S. pneumoniae forms translucent or mucoid colonies, 1–2 mm in diameter.
Optochin Sensitivity Test
The technique applying so for the presumptive identification of Streptococcus pneumoniae , which is optochin-sensitive, from other alpha-hemolytic streptococci, which are resistant.
Agglutination test: A latex reagent to detect S. pneumoniae capsular antigen.
Treatment
Useful antibacterial drugs are ampicillin, Amoxycillin, erythromycin, cotrimoxazole, doxycycline, ofloxacin, vancomycin, chloramphenicol (nitrofurantoin in case of urine ), teicoplanin, linezolid. Penicillin-resistant
strains are becoming an increasing problem.
Further Readings
- Bailey & Scott’s Diagnostic Microbiology. Editors: Bettey A. Forbes, Daniel F. Sahm & Alice S. Weissfeld, 12th ed 2007, Publisher Elsevier.
- Clinical Microbiology Procedure Handbook Vol. I & II, Chief in editor H.D. Isenberg, Albert Einstein College of Medicine, New York, Publisher ASM (American Society for Microbiology), Washington DC.
- Colour Atlas and Textbook of Diagnostic Microbiology. Editors: Koneman E.W., Allen D.D., Dowell V.R. Jr, and Sommers H.M.
- Jawetz, Melnick and Adelberg’s Medical Microbiology. Editors: Geo. F. Brook, Janet S. Butel & Stephen A. Morse, 21st ed 1998, Publisher Appleton & Lance, Co Stamford Connecticut.
- Mackie and Mc Cartney Practical Medical Microbiology. Editors: J.G. Colle, A.G. Fraser, B.P. Marmion, A. Simmous, 4th ed, Publisher Churchill Living Stone, New York, Melborne, Sans Franscisco 1996.
- Manual of Clinical Microbiology. Editors: P.R. Murray, E. J. Baron, M. A. Pfaller, F. C. Tenover and R. H. Yolken, 7th ed 2005, Publisher ASM, USA
- Textbook of Diagnostic Microbiology. Editors: Connie R. Mahon, Donald G. Lehman & George Manuselis, 3rd edition2007, Publisher Elsevier.