Microbial Assessment of Air Quality, Exposed Surfaces, and Medical Devices in Critical Care and Surgical Units of a Tertiary Hospital in Benin City, Nigeria

Background/Aim: Microbial contamination in critical care and surgical units is a significant concern due to the potential for healthcare-associated infections (HAIs), which pose a serious threat to patient safety, especially in environments with immunocompromised individuals. This study was carried out to microbiologically assess indoor air, inanimate surfaces and hospital devices in critical units/theaters and to determine their resistance markers via phenotypic methods in a tertiary hospital in Benin city, Nigeria. Methods: A cross-sectional study was conducted utilizing passive settle plate methods for air sampling and sterile swabs for inanimate surfaces and medical devices at critical care and surgical units. These samples were processed via appropriate media following standard microbiological techniques. Emergent bacterial and fungal colonies were identified, methicillin resistance was determined in staphylococci, extended-spectrum beta-lactamase (ESBL) and carbapenemase production by gram-negative bacteria (GNB) were also determined following standard techniques. Results: Among the exposed plates, the lowest count was from an empty operating theater (79 colony forming units (cfu)/m3), whereas the highest count was from renal unit (770 cfu/m3). Among high-touch surfaces, nursing stations and door handles had high yields of staphylococci, with 50% and 46.7%, respectively, with the majority being methicillin resistant, whereas tap heads had the lowest yield (13.3%). No equipment sampled was culture positive for GNB; however, GNB were mostly isolated from tap heads, sink drains and door handles. Fungi were also recovered from high-touch surfaces, namely, Aspergillus flavus and Candida spp. Among the GNB recovered, although 62.5% were ESBL-producing, Klebsiella pneumoniae had the highest number of ESBL phenotypes (88.9%), while 18.8% of GNB were carbapenemase-producing, as one each of E. cloacae, K. pneumoniae and P. aeruginosa was positive. Conclusion: Substantial microbial contamination and the presence of resistant pathogens in critical care and surgical units were observed. These findings underscore the need for enhanced IPC measures, regular environmental surveillance, and comprehensive training for healthcare workers to mitigate the risk of HAIs and curb the spread of antimicrobial resistance.