Incidence and molecular characterization of multidrug resistance in Gram‐negative bacteria of clinical importance from pharmaceutical wastewaters in South‐western Nigeria

Abstract

AbstractBackgroundThe occurrence of antimicrobial resistant bacteria in the environment presents a major threat to public health because it reduces the effectiveness of antimicrobial treatment.AimsThe study was set out to molecularly characterize Gram‐negative bacteria with multidrug resistance and resistance determinants from pharmaceutical wastewaters in Nigeria.Materials and MethodsSusceptibility of the bacterial isolates to 25 antibiotics belonging to 10 categories was tested using the disc diffusion method and Vitek 2. Screening for AmpC, Extended Spectrum Beta‐lactamase and carbapenemase production was done by Polymerase Chain Reaction and sequencing.ResultsNinety‐seven Gram‐negative bacteria, comprising 27 Enterobacteria and 70 nonfermenter bacterial isolates were detected. Antibiotic resistance observed was highest (70.1%) for sulfamethoxazole / trimethoprim and multidrug resistance was revealed in 17 bacterial strains (Klebsiella pneumoniae [7], Enterobacter gergoviae [3], Sphingomonas paucimobilis [1], Empedobacter brevis [1], Chryseobacterium indologenes [1], Pseudomonas aeruginosa [1], Burkholderia cenocepacia [1], Burkholderia cepacia and Stenotrophomonas maltophilia [1]). Extended Spectrum Beta‐lactamase (CTX‐M‐15, SHV‐12, SHV‐2) was positive for 6 K. pneumoniae strains; there were neither AmpC detected nor the production of carbapenamase in all isolates tested.DiscussionThe study confirmed the presence of multidrug resistant Gram‐negative bacteria with resistance determinants in wastewaters from pharmaceutical industries in Nigeria. Compounds of the wastewater may directly select or co‐select these multidrug resistance strains.ConclusionThe output of drug resistant bacteria into the environment is a potential risk to public health and may facilitate the spread of resistant genes.