Several studies have reported the occurrence of metal-resistant bacteria and their genes in different wastewater, but there is a dearth of information on wastewater generated from printing operations as a probable source. This study aimed at fingerprinting metal-resistance encoding genes in bacteria recovered from wastewaters of selected printeries in Ibadan, Nigeria. Wastewaters from 10 selected printeries in Ibadan were collected monthly for 12 months. The metal composition of wastewater was determined using Atomic Absorption Spectrophotometry. Metal-resistant bacteria were isolated on metal-supplemented nutrient medium, and characterized using 16S rRNA gene sequencing. Metal-resistance genes were detected using specific primers and the presence of plasmids was determined using alkaline-lysis method. Forty metal-resistant bacteria belonging to six genera; Bacillus, Klebsiella, Pseudomonas, Citrobacter, Providencia and Proteus were identified. cusCBA, encoding resistance to copper and silver was detected in nine bacteria, while pbrA (encoding lead resistance) was detected in seven Pseudomonas aeruginosa isolates. chrA, encoding resistance to chromate ions, was detected in Proteus mirabilis PW3a and two isolates of Pseudomonas aeruginosa, while chrB was detected in Providencia vermicola PWAP 3 and Proteus mirabilis PW4c. Bacillus stratosphericus PW1b possessed the copper-resistance genes, pcoA and pcoR. Thirty-six bacteria (90%) of the total bacteria possessed plasmids larger than 10 Kb in size. In conclusion, wastewater generated from printing operations could be a potential source of metal-resistant bacteria and their genes.

Indiscriminate and unguided discharge of untreated wastewater especially from abattoirs can constitute a public health threat and also stimulate the onset of co-resistance to metal and antibiotics in environmental microorganisms. It has been shown that microorganisms especially bacteria that have the capacity to resist antibiotics and heavy metals, may constitute a public health threat. This study was therefore conducted to determine the susceptibility and tolerance profile of Staphylococcus aureus isolated from abattoir effluent flowing into a receiving river around Bodija market in Ibadan to a range of antibiotics and heavy metals. Ten points were selected for sampling, and the samples were cultured on nutrient agar and mannitol salt agar. A total of 22 Staphylococcus aureus strains were obtained. They were subjected to increasing concentration of six heavy metals [lead (Pb), copper (Cu), zinc (Zn), chromium (Cr), cadmium (Cd), nickel (Ni)] and five antibiotics. Of the total isolates, 41% were resistant to all the six metals at 1500μg/ml concentration, while the others showed various degree of resistance. A percentage resistance of 22.7% was observed for tetracycline, 100% to ceftazidime, 9.1% to ciprofloxacin and vancomycin while 63.6% of the strains were resistant to oxacillin. All the strains but two showed resistance to all the metals tested, while multiple resistance to antibiotics was also observed. Further studies need to be carried out on the mechanisms of resistance of these strains.

The physicochemical, microbiological and heavy metal studies of water samples and bacteria obtained from the Dandaru River were investigated. Water samples were collected from six different sampling points along the course of the river and analysed using standard procedures. The physicochemical parameters showed that the water samples at point 5 had the highest value for all the parameters except Total Dissolved Solids. The heavy metal analysis revealed that the mean concentration of zinc, lead, chromium and iron were highest at point 5; 2.11, 0.02, 0.04 and 0.54 mg/l respectively, while that of copper and manganese concentration was highest at point 4 (0.59 and 0.41 mg/l respectively). The total heterotrophic bacteria count was between 3.6 -64.0 ×10 1 cfu/ml, with point 3 having the least value (3.6×10 1 cfu/ml); while the coliform count using Most Probable Number (MPN) tube method ranged from 350 -≥1600 MPN index/100 ml. The bacteria obtained belonged to the genera Bacillus, Enterobacter, Escherichia, Pseudomonas and Staphylococcus. On exposure to increasing concentration of six heavy metals, 47.62% of the total bacteria obtained were observed to be growing at 500 µg/ml for all the six metals employed in this study, while the others showed varying degree of tolerance to the metals.

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The growth, gut ecology and immunocompetence of Oreochromis niloticus and the resistance to Aeromonas hydrophila were investigated after been fed with diets containing dietary Curcumin longa for 12 weeks. Diets were formulated to contain 30% crude protein with diet TC1, TC2, TC3, TC4 and TC5 having 0% (control), 0.25%, 0.5%, 0.75% and 1.0% turmeric powder, respectively. Diets were allotted to groups of O. niloticus (mean weight of 1.29± 0.15 g) and replicated thrice for 84 days. Results showed that the highest mean final weight (4.79±0.04 g) was obtained in TC3 and corresponded to the treatment with the highest feed intake. A significantly high (p<0.05) specific growth rate (SGR) was observed in TC3 (0.73±0.03 %day−1) while TC4 (0.57±0.02 %day−1) gave the lowest value. The highest microbial load in the gut was observed in TC1 groups and the least in TC4 groups. Red blood cell count, hemoglobin, packed cell volume did not show significant variation (p>0.05) across treatments. However, white blood cell (WBC) count was significantly higher in TC1 (control). There was an improved immunocompetence, as aspartate aminotransferase (AST) progressively reduces in fish fed supplements. Similarly, there was a better oxidative response in the treated groups with reduced hydrogen peroxidase, increased total protein and glutathione peroxidase. Mortality ranged from 25% in TC4 to 95% in TC1 after the challenge test with A. hydrophila. This study showed that C. longa inclusion at 0.5% is more beneficial when growth and health status of O. niloticus juveniles are considered.

Background Bacterial resistance to commonly-used antibiotics has been on the increase especially in the clinical settings. This study focused on the detection of plasmid-mediated quinolone resistance (PMQR) determinants in ciprofloxacin-resistant bacteria recovered from Urinary Tract Infection (UTI) samples. Results Already characterized isolates from urine samples of UTI-diagnosed in- and out- patients were obtained from the culture pool of the Department of Medical Microbiology and Parasitology, University College Hospital (UCH), Ibadan, Nigeria. A total of seventy-three ciprofloxacin-resistant isolates were used in this study. Of the 73 UTI isolates, 43 carried at least one of the four PMQR genes targeted and they belonged to eight bacterial genera namely: Escherichia (25), Klebsiella (10), Pseudomonas (2), Proteus (2) and one isolate each belonging to Enterobacter, Acinetobacter, Citrobacter and Salmonella genera. qnrA was detected in 10.9% (8/73) of the isolates while the occurrence of qnrB and qnrS was 32.9% (24/73) and 20.5% (15/73), respectively. The quinolone efflux pump (qepA) was detected in 9/73 (12.3%) of the isolates. Thirty of the isolates carried only one PMQR gene, while thirteen carried two PMQR genes. There was no carriage of more than two PMQR genes in the forty-three isolates from which PMQR genes were detected. Conclusion This study reports the carriage of PMQR determinants by eight of the nine Gram-negative bacterial genera from urinary sources in patients attending the University College Hospital, Ibadan over the four-month period of study. This is quite worrisome as it suggests a high contribution of UTI cases to the burden of quinolone resistance. There is a need for more studies of this nature in other hospitals in Nigeria, to develop a database on the contribution of UTI cases to quinolone resistance.

Untreated wastewater from abattoir operations contains nutrients and other components that aid the growth of microorganisms especially bacteria. They also serve as a habitat for potentially pathogenic bacteria which might be a source of public health concern. The study was carried out to determine the antibiotics susceptibility profile of Gram-negative bacteria (Pseudomonas and Escherichia coli) to selected antibiotics. Wastewater samples were collected from ten different sampling points and cultured on Eosin Methylene Blue (EMB) and King's B medium. The bacterial strains obtained from the wastewater samples were subjected to antibiotics susceptibility tests, using the disc diffusion technique. A total of 60 Pseudomonas and 100 Escherichia coli were isolated out of which none of the Pseudomonas strains showed resistance to imipenem, colistin sulphate, meropenem and aztreonam, while 100% resistance was observed to ceftazidime and piperacillin. All the Escherichia coli strains were resistant to oxacillin and ceftazidime, while the percentage resistance to aztreonam, ertapenem, cefoxitin and tetracyline was 6%, 11%, 43% and 58% respectively. Eighty-five percent (85%) of the total Escherichia coli showed resistance to more than two antibiotics, while 14% showed resistance to ceftazidime and oxacillin, with only one isolate showing resistance to ceftazidime and cefoxitin. There is the need for an effective treatment of wastewater generated from abattoir operations to prevent the potential spread and transmission of antibiotic resistant bacteria to the human population who depends heavily on some of the water bodies, receiving input from abattoir wastes.