Genetic Diversity and Antimicrobial Resistance of Escherichia coli from Human and Animal Sources Uncovers Multiple Resistances from Human Sources

Escherichia coli are widely used as indicators of fecal contamination, and in some cases to identify host sources of fecal contamination in surface water. Prevalence, genetic diversity and antimicrobial susceptibility were determined for 600 generic E. coli isolates obtained from surface water and sediment from creeks and channels along the middle Santa Ana River (MSAR) watershed of southern California, USA, after a 12 month study. Evaluation of E. coli populations along the creeks and channels showed that E. coli were more prevalent in sediment compared to surface water. E. coli populations were not significantly different (P = 0.05) between urban runoff sources and agricultural sources, however, E. coli genotypes determined by pulsed-field gel electrophoresis (PFGE) were less diverse in the agricultural sources than in urban runoff sources. PFGE also showed that E. coli populations in surface water were more diverse than in the sediment, suggesting isolates in sediment may be dominated by clonal populations.Twenty four percent (144 isolates) of the 600 isolates exhibited resistance to more than one antimicrobial agent. Most multiple resistances were associated with inputs from urban runoff and involved the antimicrobials rifampicin, tetracycline, and erythromycin. The occurrence of a greater number of E. coli with multiple antibiotic resistances from urban runoff sources than agricultural sources in this watershed provides useful evidence in planning strategies for water quality management and public health protection

Escherichia coli Bacteriocins: Antimicrobial Efficacy and Prevalence among Isolates from Patients with Bacteraemia

Bacteriocins are antimicrobial peptides generally active against bacteria closely related to the producer. Escherichia coli produces two types of bacteriocins, colicins and microcins. The in vitro efficacy of isolated colicins E1, E6, E7, K and M, was assessed against Escherichia coli strains from patients with bacteraemia of urinary tract origin. Colicin E7 was most effective, as only 13% of the tested strains were resistant. On the other hand, 32%, 33%, 43% and 53% of the tested strains exhibited resistance to colicins E6, K, M and E1. Moreover, the inhibitory activity of individual colicins E1, E6, E7, K and M and combinations of colicins K, M, E7 and E1, E6, E7, K, M were followed in liquid broth for 24 hours. Resistance against individual colicins developed after 9 hours of treatment. On the contrary, resistance development against the combined action of 5 colicins was not observed. One hundred and five E. coli strains from patients with bacteraemia were screened by PCR for the presence of 5 colicins and 7 microcins. Sixty-six percent of the strains encoded at least one bacteriocin, 43% one or more colicins, and 54% one or more microcins. Microcins were found to co-occur with toxins, siderophores, adhesins and with the Toll/Interleukin-1 receptor domain-containing protein involved in suppression of innate immunity, and were significantly more prevalent among strains from non-immunocompromised patients. In addition, microcins were highly prevalent among non-multidrug-resistant strains compared to multidrug-resistant strains. Our results indicate that microcins contribute to virulence of E. coli instigating bacteraemia of urinary tract origin

Comparative Assessment of Performance of Urban Water Supply Systems in Small Towns of Zimbabwe

One of the major challenges faced by residents of small urban towns globally is that of poor Water and Sanitation Service delivery. The management of urban water services has become very important in the wake of the cholera outbreak of 2008-09 which claimed more than 4000 lives in Zimbabwe. The outbreak was linked to poor WS systems delivery. The poor quality of service was attributed to the economic collapse of the country which to some extent affected the capacity of local councils to manage water supply services. The economic collapse also affected the capacity of residents to pay for water services. In the aftermath of the near collapse of the water supply systems in urban areas, the government directed the Zimbabwe National Water Authority (ZINWA) to take-over the water supply systems in most of the urban areas, resulting in towns such as Gokwe and Karoi having their water supply systems managed by ZINWA. However, in some urban areas local councils retained the management of water supply systems. This study compares the water supply systems of selected small urban towns in Zimbabwe which are Chipinge, Gokwe, Karoi and Rusape. Financial and governance aspects of water resources management are major contributors to the collapse or sustainability of water supply systems and these were investigated. Data collection for the study was done through key informant interviews covering governance issues, revenue collection, water tariff setting processes, technical issues and stakeholder involvement in urban water management. A total of 765 household questionnaires investigating customer perceptions on service delivery, willingness and ability to pay, impact of water tariffs on household water use and stakeholder involvement in the management of urban water supply services were administered in the four towns. Both the ZINWA and council water supply management systems in the four towns were found to have active institutional and legal structures but service delivery was generally poor. Consistence of water supply in the areas was found to be largely affected by recurrent power cuts while the breakdown of equipment affected water treatment and supply capacity. Although there was high meter coverage (ranging from 82-94%) functionality of meters was low mostly for the council managed water supply systems. Revenue collection was found to be very low accounting for less than 30% of the billed amount for both water supply systems. This was due to customers‟ low willingness to pay for reasons which included poor service delivery, poor customer care service, inaccuracy of bills and poor water quality. Unaccounted for water was found to be above 30% for council managed systems and less than 15% for ZINWA managed water supply systems. Findings also show that there is little involvement of stakeholders in the setting of water tariffs. In conclusion, power cuts, poor customer care services, increased unaccounted for water, low stakeholder participation among other things have contributed to poor service delivery and low revenue collection in the four towns. Stakeholder participation is critical for the sustainability of urban water management and water supply systems. There was no significant difference in performance between Local council and ZINWA managed water supply systems because the performance indicators varied between the systems.,WATERne