Burden of bacterial contamination: A cross-sectional study to estimate the bacterial isolates from the surfaces of a bacteriology laboratory

ABSTRACT

Background: Contamination in a bacteriology laboratory setup may result in erroneous interpretation. Aim and Objective: To estimate the bacterial isolates from different surfaces of the bacteriology laboratory of a tertiary care hospital. Materials and Methods: A total number of 165 samples were taken from different surfaces of the laboratory including tabletops, floor, walls, and workbench tops at the beginning of morning session for consecutive thirty working days (June 2019). Surface swab technique was followed using pre-incubated Nutrient agar (Basal plate), Mac-conkey’s agar (Selective and differential media), and Blood agar plates (enriched media). Aerobic incubation was done overnight at 37°C. Discrete colonies were studied by Gram, Ziehl-Neelsen, and Albert staining followed by the tests for motility and a series of biochemical reactions. Results: Out of 165 collected swabs, growth was observed in 23 (13.93%). Out of these 23 isolates, none was from the workbench top. Majority (47.82% i.e., 11/23) was from the floor. Amongst 23 isolates, 14 (60.86%) were Gram-positive in nature and 7 (30.43%) found to be motile. Isolated bacteria comprised Micrococcus spp. (34.78% i.e., 8/23), Pseudomonas spp. (17.39%,4/23), Coagulase-negative Staphylococcus spp. (13.04% i.e., 3/23), Bacillus spp. (13.04%, i.e., 3/23) and Acinetobacter spp. (21.73% i.e., 5/23). From floor, majority of the isolates were Micrococcus spp. (45.45%, i.e., 5/11) whereas in wall, mostly Bacillus spp. (33.33%, i.e., 3/9) and tabletop, all of the isolates were Coagulase-negative Staphylococcus spp. Conclusion: Vigilant disinfection and maintenance of personal hygiene of laboratory workers are essential to eliminate contamination.