MICROBIAL LOAD AND INDOOR AIR QUALITY OF OPERATING THEATRES IN THE UNIVERSITY COLLEGE HOSPITAL, IBADAN

ABSTRACT

Microbial contamination of indoor air of operating theatres is one of the risk factors for the development of Surgical Site Infections (SSI). Operating theatre environment, including personnel, can become contaminated with microorganisms capable of causing SSI, morbidity, prolong hospitalization of patients or even death. Studies on indoor air quality particularly the air-borne microbes that are associated with SSI have not been adequately investigated. This study was therefore designed to determine the air-borne microbial load and indoor air quality of operating theatres in the University College Hospital, Ibadan. A descriptive cross-sectional design which involved purposive selection of seven operating theatres viz: main (T1, T2, T3, T4, T5), gynaecology (T6) and emergency (T7) theatres was adopted. Temperature and Relative Humidity (RH) of the indoor environments of the theatres were measured three times a week before and after surgery using multi-tester N21FR. Values obtained were compared with the Association of peri-Operative Registered Nurses (AORN) guideline limits of 22.0ºC and 55.0% respectively. Particulate matter (PM10) concentrations in the indoor environments were measured using Met-one particle counter and compared with the World Health Organisation Guideline Limits (WHOGLs) of 50µg/m³. Air-borne microbial samples were collected using non-volumetric method. Total Bacterial Counts (TBC) and Total Fungal Counts (TFC) per cubic-metre were determined and compared with the American Industrial Hygiene Association (AIHA) guideline limit of 50 cfu/m3 . Data were analysed using descriptive statistics, ANOVA and Spearman’s rank correlation at 5% level of significance. Indoor temperature and Relative Humidity across the seven theatres were significantly higher after surgery (29.9±1.5ºC and 62.1±7.0%) than before surgery (27.6±1.1ºC and 61.2±8.2%) and were not within AORN guideline limits. Indoor PM10 after surgery (60.2±21.2µg/m³) was higher than before surgery (47.8±18.3µg/m³) and the WHOGLs. Indoor TBC after surgery was 2.1x102 cfu/m3 and then was higher than before (0.5x102 cfu/m3 ). Similarly, indoor TFC across the theatres after surgery (0.17x102 cfu/m3 ) was higher than before (0.03x102 cfu/m3 ) but lower than the AIHA guideline limits. Streptococcus spp., Staphylococcus spp. and Aspergillus spp. were among the organisms isolated from the indoor air environment before and after surgery. Emergency theatre T7 recorded the highest RH (61.9±8.0%), PM10 (69.1±25.3µg/m³), TBC (1.52x102 cfu/m3 ) and TFC (0.16x102 cfu/m3 ). A significantly positive correlation was observed between indoor TFC and RH (r = 0.124) and indoor TBC and PM10 (r = 0.099). Microbial load in the selected operating theatres was higher than the internationally recommended values for an ideal and safe operating theatre. Therefore, operating techniques and environmental conditions should be properly monitored to ensure compliance with recommended standards.