Detection of Metallo-β-Lactamase-Producing Gram-Negative Bacterial Isolates from Patients with Lower Respiratory Tract Infections in a Tertiary Hospital in Benin City, Nigeria

ABSTRACT
Objective: Lower respiratory infections (LRTIs) are a persistent threat to quality of life and resistant bacterial strains serve to worsen treatment outcomes. This study aimed at investigating the prevalence of bacteria-producing metallo-β-lactamase (MBL) among patients with lower respiratory tract infections in a tertiary hospital in Benin City, Nigeria.
Methodology: A cross-sectional study was conducted at the University of Benin Teaching Hospital, Benin City. Questionnaires were filled for each study participant presenting with signs and symptoms of LRTI. Sputum specimens were collected from each patient into sterile wide-mouth containers and sent to the Medical Microbiology Laboratory for microbiological processing. Emergent bacterial colonies were identified and antimicrobial susceptibility tests carried out using standard techniques. Result: A total of 185 Gram negative bacterial isolates were recovered from the sputum specimens of patients. These included Enterobacteriaceae (160), Acinetobacter spp (7), Alkaligenes spp (4) and P.aeruginosa (14). A total of 9 (4.7%) isolates were MBL-producing; among them Hafnia alvei was most likely MBL-producing when compared with other isolates (0.0191). Very poor susceptibility was observed for MBL-producing bacteria as 100% multi-drug resistance was observed, non-MBL-producing isolates showed 63.8% MDR.
Conclusion: The prevalence of MBL-producing bacteria causing LRTI in this study was 4.7%. The study harps on prudence in the use of antibiotics in order to minimize the emergence and spread of resistant bacterial strains in our setting.