Aims and objectives: To identify the prevalence of bacteremia and the spectrum of antimicrobial sensitivity in our community, because it will guide the clinician to institute proper antimicrobial therapy.

Background: Bacteremia originates from either intravascular sites or extraVascular sites. In case of bloodstream infection, either Gram-positive or Gram-negative bacteria are responsible. Of these bacterial isolates, Gram-negative bacteria are responsible for higher mortality and morbidity. Since 20 to 30 years, coagulase-negative Staphylococci are responsible for most infection.

Materials and methods: In this retrospective study, blood samples were collected aseptically from 11,581 patients and were injected into the bottles containing bile-broth and brainheart infusion broth and allowed to be incubated at 37°. Then subculture was done on blood agar, chocolate agar, as well as MacConkey agar media and was kept for 7 days or till the appearance of growth of the organism. After identification of isolates, Kirby Bauer disk diffusion test on Mueller-Hinton agar II was performed to detect antimicrobial sensitivity.

Results: Our study documented 8.58% positive cultures in the last 7 years. Gram-negative bacterial isolates were significantly higher than Gram-positive isolates (64.19% vs 34.80%, p = 0.00). Lowest number of positivity was seen in Morganella (0.40%) followed by Proteus (0.50%) and Enterococcus faecium (0.90%) in ascending order. Males were significantly more culture positive than females (549/994 vs 445/994, p = 0.00). Most common bacterial isolates were (coagulase negative Staphylococci) CoNS (239, 24.04%) followed by Klebsiella including ESBL (extended spectrum beta-lactamase), carbapenamase producer (234, 23.74%) and Escherichia coli (110, 11.06%). E. coli was >75% sensitive to imipenem group, polymyxin B (98.18%), colistin (96.36%), and amikacin (80.9%). Coagulase negativeStaphylococci showed more than 60% sensitivity to levofloxacin (76.98%), amikacin (82.84%), tigecycline (87.44%), vancomycin (94.45%), teicoplanin (91.63%), linezolid (91.21%), gentamicin (76.56%), netilmicin (74.47%), and tetracycline (75.31%). Klebsiella (non-ESBL and carbapenemase producer) was highly sensitive to polymyxin B (93.06%), colistin (91.90%), meropenem (65.31%), and imipenem (94.73%). Extended spectrum beta-lactamase-producing Klebsiella showed increased sensitivity to meropenem (89.47%), imipenem (94.73%), ertapenem (81.57%), polymyxin B, and colistin (97.36% each).

Conclusion: Positive cultures were 8.58% in the last 7 years. Gram negative bacterial isolates were significantly higher. Males were more culture positive. Most common bacterial isolates were CoNS followed by Klebsiella species and E. coli. Gram-negative bacterial isolates were highly sensitive to piperacillin, cefoperazone, imipenem, meropenem, aminoglycoside group of antibiotics, tigecycline, polymyxin B and colistin. Gram-positive bacterial isolates were sensitive to piperacillin, cefoparazone, vancomycin, teicoplanin, linezolid and clindamycin. Salmonella typhi were sensitive to ampicillin, cefoparazone, cefepime, azithromycin, chloramphenicol, and fluoroquinolones. Acinetobacter showed > 50% sensitivity to cefepime and Pseudomonas showed > 50% sensitivity to cefotaxime and levofloxacin. So to prevent resistance of bacterial isolates, a proper antibiotic guideline should be maintained.

Keywords: Blood culture and sensitivity, Coagulase negative Staphylococcus, E. coli, Gram-positive and Gram-negative bacterial isolates, Klebsiella, Tertiary care hospital.

How to cite this article: Saha AK, Munsi K, Dhar P. Blood Culture and Sensitivity Profile Study in a Tertiary Medical Hospital in Kolkata, West Bengal: 7 Years’ Experience. MGM J Med Sci 2016;3(1):18-25.

Source of support: Nil

Conflict of interest: None