The aim of this study was to isolate and identify environmental bacteria from various raw water sources as well as the drinking water distributions system in Mafikeng, South Africa, and to determine their antibiotic resistance profiles. Water samples from five different sites (raw and drinking water) were analysed for the presence of faecal indicator bacteria as well as Aeromonas and Pseudomonas species. Faecal and total coliforms were detected in summer in the treated water samples from the Modimola dam and in the mixed water samples, with Pseudomonas spp. being the most prevalent organism. The most prevalent multiple antibiotic resistance phenotype observed was KF-AP-C-E-OT-K-TM-A. All organisms tested were resistant to erythromycin, trimethoprim, and amoxicillin. All isolates were susceptible to ciprofloxacin and faecal coliforms and Pseudomonas spp. to neomycin and streptomycin. Cluster analysis based on inhibition zone diameter data suggests that the isolates had similar chemical exposure histories. Isolates were identified using gyrB, toxA, ecfX, aerA, and hylH gene fragments and gyrB, ecfX, and hylH fragments were amplified. These results demonstrate that (i) the drinking water from Mafikeng contains various bacterial species and at times faecal and total coliforms. (ii) The various bacteria are resistant to various classes of antibiotics.

Mafikeng, the capital of the North West Province, receives water from two sources, namely the Molopo eye and the Modimola dam. Once treated, the potable water is mixed and supplied to the city via distribution systems. This study was designed to assess the quality of drinking water in Mafikeng and also to determine whether the water from the two sources has an impact on the mixed water quality. Physico-chemical parameters and bacteriological quality (faecal coliforms (FCs), total coliforms (TCs), heterotrophic bacteria and Peudomonas spp.) was monitored at three drinking water sites weekly for 4 months. The results revealed that the physico-chemical quality of the water was generally acceptable. The pH ranged from 5.7 ± 0.18 to 8.6 ± 0.14, the temperature ranged from 18.3 ± 0.69 to 25.1 ± 0.69 W C and the total dissolved solids (TDS) ranged from 159.9 ± 22.44 to 364.4 ± 12.44 mg/l. These values are within the target water quality range for drinking water as prescribed by WHO, Department of Water Affairs and SANS 241. What is of concern was the microbial quality of the water. FCs, TCs, heterotrophic bacteria and Pseudomonas spp. were present in some of the treated water samples. The most significant finding of this study is that all drinking water samples were positive for Pseudomonas spp. (>100/100 ml).

The effect of the ef¯uent from a chicken meat-processing plant on the antibiotic-resistant bacterial pro®le was investigated in an almost closed water reticulation system. Of the 273 faecal coliform isolates 256 (93%) were resistant to one or more of the eight antibiotics tested. The most prevalent isolates were for the b-lactam antibiotics ampicillin and cephalothin followed by the sulphonamides sulphatriad and cotrimoxazole. Eleven different resistance patterns were identi®ed with a single pattern, comprising of ampicillin-, cephalothin-, streptomycin-, sulphatriad-, cotrimoxazole-and tetracyclin-resistant isolates, dominating the meatprocessing ef¯uent. An apparent correlation was observed between the speci®c use of certain antibiotics and the prevalence of the corresponding resistant bacterial isolates. The drugs used to treat the occasional infections, belonging to the b-lactam and sulphonamide group of antibiotics, seemed to have a more pronounced effect on the antibiotic-resistant bacterial pro®le in the primary water source than those drugs used as feed additives, oxytetracyclin and the aminoglycoside¯avomycin.

Poor quality source water and poorly treated reused wastewater may result in poor quality drinking water that has a higher potential to form biofilms. A biofilm is a group of microorganisms which adhere to a surface. We investigated biofilm growth in the drinking water distribution systems in the Mafikeng area, in the North- West Province of South Africa. Analysis was conducted to determine the presence of faecal coliforms, total coliforms, Pseudomonas spp. and Aeromonas spp. in the biofilms. Biofilms were grown on a device that contained copper and galvanised steel coupons. A mini tap filter – a point-of-use treatment device which can be used at a single faucet – was also used to collect samples. Scanning electron microscopy demonstrated that multi-species biofilms developed on all the coupons as well as on the point-of-use filters. Galvanised steel and carbon filters had the highest density of biofilm. Total coliforms, faecal coliforms and Pseudomonas spp. were isolated from raw water biofilm coupons only. Aeromonas spp. and Pseudomonas spp. were isolated from filters. The susceptibility of selected isolates was tested against 11 antibiotics of clinical interest. The most prevalent antibiotic resistance phenotype observed was KF-AP-C-E-OT-K-TM-A. The presence of virulence genes was determined using the polymerase chain reaction. These results indicate that bacteria present in the water have the ability to colonise as biofilms and drinking water biofilms may be a reservoir for opportunistic bacteria including Pseudomonas and Aeromonas species.