Carbapenemase-Producing Pseudomonas aeruginosa Isolates: Prevalence and Their Phenotypic Characteristics in Four Health Facilities in Calabar, Nigeria

Emergence of multi-drug-resistant Pseudomonas aeruginosa is one of the challenging problems of antimicrobial chemotherapy which has become a global public health concern. This cross-sectional study was designed to determine the antibiotic resistance profile of this important pathogen and the prevalence of carbapenemase-producing P. aeruginosa strains isolated in four hospitals in Calabar Metropolis. Three hundred and twelve suspected P. aeruginosa strains non-repetitively isolated from different clinical speci¬mens in four hospitals were characterized and re-identified with the Microgen™ GNA+B-ID system. An¬timicrobial susceptibility testing was performed using the disc diffusion method. Phenotypic tests for the detection of extended-spectrum beta-lactamases (ESBLs), inducible cephalosporinases (AmpC), and car¬bapenemases by Carba NP test were performed following CLSI guidelines. P. aeruginosa ATCC 27853 was used for quality control. Overall prevalence of confirmed P. aeruginosa was 63.14% (197/312). Of these 197 isolates, 31.47% produced AmpC and 41.12% produced ESBLs. Thirty (15.23%) P. aeruginosa isolates produced carbapenemases, which comprised 40.0% (12/30) Class A and 60.0% (18/30) Class B metallo-beta-lactamase (MBL). Significant multidrug resistance >70% was observed among the isolates. Analysis of the risk factors showed strong associations between carbapenemase-producing Pseudomonas aeruginosa-related infections and hospitalization (p = 0.03), surgery (p = 0.03), and intensive care wards (p = 0.04). The study revealed a significant burden of multidrug-resistant strains of carbapenemase-produc¬ing Pseudomonas aeruginosa in Calabar Metropolis. To avert an impending public health crisis due to the spread of these strains, hospital infection control units must be established as a matter of policy for adequate surveillance and antimicrobial stewardship.