Reservoirs of Nosocomial Pathogens in Intensive Care Units: A Systematic Review

Background: Nosocomial pathogens are known to exacerbate morbidity and mortality in contemporary critical healthcare. Hospital fomites, which include inanimate surfaces, have been identified as "breeding grounds" for pathogens that cause nosocomial infections. This systematic review aimed to deliver incisive insights on nosocomial pathogens in intensive care units (ICUs) and the role of fomites as potential reservoirs for their transmission. Method: An extensive exploration of electronic databases, including PubMed and Scopus, from 1990 to 2023, was carried out between 25th and 29th May 2023, per standard PRISMA guidelines. Information were extracted from articles that reported on fomites in the ICU. Studies that did not quantitatively report the fomite contamination, and those that exclusively took samples from patients in the ICU were excluded from the analysis. Results: About 40% of the total samples collected on fomites from all the studies yielded microbial growth, with species of Staphylococcus being the most predominant. Other prevalent microbes were Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Candida spp., Enterococcus sp., and Enterobacter sp. The neonatal intensive care unit (NICU) had the highest proportion of contaminated fomites. Among known fomites, the sphygmomanometer exhibited a 100% detection rate of nosocomial pathogens. This included E. aerogenes, Staphylococcus aureus, coagulase-negative Staphylococci (CoNS), E. coli, and K. pneumoniae. Multidrug-resistant (MDR) bacteria, such as methicillin-resistant S. aureus (MRSA), vancomycin-resistant Enterococci (VRE), extended-spectrum beta-lactamase (ESBL)-producing E. coli, and MDR Pseudomonas aeruginosa were commonly isolated on fomites in the ICUs. Conclusion: Many fomites that are readily used in patient care in the ICU harbour nosocomial pathogens. The most common fomite appeared to be mobile phones, sphygmomanometers, and stethoscopes, with Staphylococcus being the most common contaminant. Consequently, the need for rigorous disinfection and sterilization protocols on fomites in the ICU cannot be overemphasized. Additionally, heightened awareness on the subject among health professionals is crucial to mitigating the risk and burden of nosocomial infections caused by drug-resistant bacteria.