Background The occurrence of antimicrobial resistant bacteria in the environment presents a major threat to public health because it reduces the effectiveness of antimicrobial treatment. Aims The study was set out to molecularly characterize Gram‐negative bacteria with multidrug resistance and resistance determinants from pharmaceutical wastewaters in Nigeria. Materials and Methods Susceptibility 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. Results Ninety‐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. Discussion The 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. Conclusion The output of drug resistant bacteria into the environment is a potential risk to public health and may facilitate the spread of resistant genes.

Cronobacter sakazakii formerly known as Enterobacter sakazakii, is a bacterium with a rare cause but often fatal infection of the bloodstream and central nervous system. Infants with weakened immune systems, particularly premature infants, are most likely to contact a Cronobacter infection, although the bacteria have caused illnesses in all age groups. Most cases of C. sakazakii infection come from powdered infant formula (PIF) contaminated with the bacterium. Although relatively little information is known about the existence of Cronobacter in the environment, more reservoirs are being identified, such as water, soil and plant material. Wastewaters from 6 pharmaceutical industries located in a southwestern state in Nigeria were sampled and analyzed. Bacteria were isolated using standard methods and species identification was determined by Gram staining, lactose fermentation, oxidase, catalase and Vitek 2. Antibacterial susceptibility to 25 antimicrobial agents was tested by the disc diffusion method and Vitek 2. Fifty nine Gram-negative bacteria were isolated and identified; one was identified as C. sakazakii. The bacterium was susceptible to all antibiotic mentioned but resistant to augmentin (amoxicillin/clavulanate) and colistin which are high potent drugs for the treatment of very stubborn infections. The public health implication of this fact is that this bacterium could be harbouring resistant genes that can be transferred through water ways such as the pharmaceutical wastewaters to bacteria of the same or different species of clinical importance. Therefore, continuous surveillance of the environmental reservoirs of antibiotic resistant bacteria is necessary to prevent their further spread.

We conducted a microbiological and toxicological profiling of a pharmaceutical wastewater, one of the major wastes entering the Lagos lagoon. The morphological characterization of seven bacterial isolates from the wastewater indicated that 4 of them were gram positive bacilli while 3 were cocci of both gram reactions. The bacterial isolates exhibited varying degrees of enzyme activities but most were able to hydrolyze starch to yield amylase. Only 3 of the isolates showed prospects as antibacterial agents, given their moderate inhibition to Staphylococcus xylosus relative to 8 other species tested. Overall, 81.3% of the isolates were resistant, and 3.3% were susceptible while 15.4% of the isolates showed intermediate sensitivity to the antibiotics. The assessment of antioxidant activities in liver samples of Nile tilapia, Oreochromis niloticus, exposed to sublethal concentrations of the effluents indicated some form of oxidative stress given the higher levels of lipid peroxidation product, malondialdehyde, in the exposed fishes relative to the control kept in dechlorinate tap water. But for reduced glutathione, activities of the antioxidative stress enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione-s-transferase (GST), were higher in the effluent exposed tilapia. Responses were not dose dependent and enzyme activities were often higher at day 14 compared to day 28. This relevance of the findings to water quality was discussed.