Providing safe water through water reuse is becoming a global necessity. One concern with water reuse is the introduction of unregulated contaminants to the environment that cannot be easily removed by conventional wastewater treatment plants (WWTP). The occurrence of ampicillin, sulfamethoxazole, ciprofloxacin, and tetracycline-resistant Escherichia coli through the treatment stages of a WWTP (raw sewage, post-secondary, post-UV and post-chlorination) was investigated from January to May 2016. The highest concentrations of antibiotic resistant E. coli in the effluent were detected in April after rainfall. Ampicillin-resistant E. coli was the most common at the post UV and chlorination stages comprising 63% of the total E. coli population. The minimum inhibitory concentration (MIC) analysis showed that one in five isolates was resistant to three or more antibiotics, and the majority of these E. coli were resistant to ampicillin, followed by sulfamethoxazole and ciprofloxacin. The highest MIC was detected at the finished water after application of multiple disinfection methods. Tetracycline resistance was the least observed among others, indicating that certain drug families may respond to wastewater treatment differently. Currently, there are no policies to enforce the monitoring of antibiotic-resistant pathogen removal in WWTP. Better guidelines are needed to better regulate reuse water and prevent health risk upon exposure to antibiotic-resistant bacteria.

One of the main impacts of urban sprawl in rapidly growing countries has been contamination of coastal environments by waterborne pathogens, posing a critical risk to ecosystem and human health. Microbial source tracking (MST) has been a robust tool to identify the origin of these pathogens globally. This study compared the occurrence of a human‐associated Bacteroides marker (BT‐α) with faecal indicator bacteria (FIB) in an urban estuary (Golden Horn, Istanbul, Turkey). Faecal coliform (culture method), enterococci (both culture and qPCR method) concentrations and physicochemical variables were compared with the BT‐α concentrations in monthly collected samples for a year (n=108). Enterococci concentrations detected by culture and qPCR were positively correlated (r = 0.86, p < 0.01) suggesting that qPCR can be an alternative method for monitoring. BT‐α marker was positive for 30% of the samples and positively correlated with enterococci (r = 0.61 and r = 0.64 for culture and qPCR methods respectively, p < 0.01). Rainfall had a moderate positive correlation with all faecal/MST indicators suggesting combined sewer overflows also severely impacted estuarine water quality. The high FIB and BT‐α concentrations at upper estuary suggested that faecal pollution mainly originated from the peri‐urban settlements around two creeks entering the estuary.

Sachet water is one of the primary sources of drinking water in rapidly growing countries. A study to assess the microbiological quality of sachet water in 21 different brands was conducted in Ghana. Culturable total coliform was positive in 87% of the samples collected, whereEscherichia colicolonies were absent. The analysis of quantitative polymerase chain reaction results indicated the presence ofE. coligenes in 44.6% of the samples, with the highest concentration up to 3,166 CCE/100 ml. Microbial source tracking analyses showed that the source ofE. coligenes did not originate from sewage contamination because the human-associated HF183 marker was not detected. Of the 175 samples tested, 71% did not mention any water treatment before filling the packages. These results suggest non-human sources of contamination, such as biofilm formation in the pipelines used to fill these packages due to poor disinfection. Our study shows an urgent need for increased regulation and standardized manufacturing of sachet water to ensure safe drinking water.