Common Contaminants of Bacteriology Laboratory: Microbiological Paramores

Frequent environmental contaminants within microbiology laboratory create not only diagnostic dilemmas but also poses major risk for health care workers and patients. Objective of our study was to isolate and identify the common laboratory contaminant bacteria with an ultimate goal to reduce false positive culture reports as well as Laboratory acquired infections. The study was conducted in Microbiology laboratory of a tertiary care hospital over a period of six months. A total number of 100 samples were collected from different areas of laboratory including air, surfaces, hands and clothing of the laboratory personnel by settle plate method, surface swab method, fingerprint impressions and sweep plate method respectively using pre incubated Mac-conkey’s and Blood agar plates, incubated overnight at 370c. The next day, discrete colonies were further studied by standard Microbiological protocols. Indeterminant biochemical results were confirmed with Biomeriux VITEK-2 AES. Out of 100 collected samples, growth was observed in 34 (34%).Out of 34 culture positive samples, Micrococcus was isolated in 18(52.94%) followed by Bacillus subtilis (confirmed by VITEK-2 AES) in 8 (23.52%). Diphtheroids were isolated in 4 samples (11.3%). Staphylococcus epidermidis was isolated in 3 cases (8.8%) and in one sample, Staphylococus aureus was isolated. Micrococcus spp. were obtained mainly from surfaces (66.67%) whereas Bacillus subtilis was from air (75%). Precaution should be taken to get rid of these organisms from laboratory by means of proper laboratory disinfection and sterilization as well as personal hygiene of laboratory workers.