Multidrug-Resistant Bacteria In Hospital Wastewater Of The Korle Bu Teaching Hospital

Abstract

Background: Antimicrobial resistance (AMR) is one of the top ten (10) public health threats. It is, therefore, imperative to scale up efforts aimed at tackling the AMR menace. One approach could involve expanding the range of AMR surveillance targets to include hospital wastewater (HWW), a target that has largely been overlooked by researchers. General Aim: The aim of this study was to evaluate the occurrence of multidrug-resistant bacteria in hospital wastewater of the Korle Bu Teaching Hospital (KBTH). Methodology: This was a longitudinal study involving a total of 288 hospital wastewater samples consecutively collected across twelve weeks from the pool of wastewater emanating from two critical care units of the Korle Bu Teaching hospital, that is, the Child Health Unit and the Maternity Unit on Mondays and Thursdays, each week. The samples were immediately transported on ice to the laboratory and cultured for bacteria, which were identified using the Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) technique and subjected to antimicrobial susceptibility testing via the Kirby-Bauer method. Results: In total, 294 bacteria of 23 different types, all being Gram-negative, were isolated from the 288 samples. The predominant ones were Escherichia coli (30.6%, n = 90), Klebsiella pneumoniae (11.2%, n = 33), Citrobacter freundii (10.9%, n = 32), Alcaligenes faecalis (5.8%, n =17), and Pseudomonas mendocina (5.4%, n = 16). Escherichia coli was the only organism whose proportion significantly differed between the two units studied [Maternity Unit = 23.8%, n = 37; Child Health Unit = 38.0%, n = 53, p = 0.02], and it persisted for weeks 1 to 6 in the wastewater from the Maternity Unit and Weeks 6 to11 in the wastewater from the Child Health Unit, while occurring intermittently during the other periods. The prevalence of multidrug resistance among the isolates was 55.4% (n = 163) [Maternity Unit = 53.4%, n = 87; Child Health Unit = 46.6%, n = 76, p = 0.22]. Moreover, the prevalence of extended-spectrum beta lactamase (ESBL) producers was 15.6% (n = 46) [Maternity Unit = 18.4%, n = 26; Child Health Unit = 13.1%, n = 20, p = 0.21]. E. coli accounted for the most ESBL-producing organisms (28.9%, n =26). Conclusion: The wastewater generated by the Maternity and Child Health Units of KBTH harboured a wide range of multidrug resistant bacteria, with a good proportion of these being ESBL producers, and the predominant and persistent one being Escherichia coli. The study thus identifies the wastewater of KBTH as an important source of infection transmission, and underscores the significance of appropriate treatment of wastewater of the hospital and other clinical and related settings prior to its discharge.