Microbial isolations from maxillofacial operation theatre and its correlation to fumigation in a teaching hospital in India

Abstract

Postoperative infection and sepsis remain a major cause of morbidity among patients undergoing surgery. Maintenance of strict asepsis is essential if post-operative infection and its consequences are to be minimized. In developing countries maintenance of asepsis in most operation theatres is limited to fumigation and mopping. Clinical trials have confirmed that 80-90 % of bacterial contaminants found in wound after surgery come from microbes present in air of operating theatre. A study was conducted to evaluate the microbiological contamination of maxillofacial operation theatres in India and its correlation to weekly fumigation. A total of 6,723 culture plates, including 2,241 air and 4,482 swab samples were studied. Samples were collected at prefumigation, midcycle and post-fumigation stages and were cultured over three different medias. Predominant bacteria identified were Staphylococcus aureus (76 out of 83 samples by active air sampling) followed by Streptococcus while Aspergillus was the main fungal isolate. Formaldehyde based fumigation decreased the colony forming units (cfu/m(3)) of all organisms in different samples and was found to be highly effective against Fungi and E. coli. Literature suggests that for conventional operating theatres the bioload should not exceed 35 cfu/m(3) in an empty theatre. In our study the cfu levels were always lower immediately after fumigation was carried out; however they moved up beyond this limit as the days passed. This implies that once a week fumigation with formaldehyde is less than optimal to achieve acceptable levels of disinfection.

Keywords: Air sampler; Colony forming unit; Formaldehyde; Fumigation; Settle plate method.

Fig. 1

Average cfu at different times using air sampler on different culture media

Fig. 2

Average cfu on settle plate sampling using different media at different times