In Ahwaz, a city in west southern Iran, the majority of households are using Point of Use (PoU) water treatment units. The heterotrophic plate count (HPC) bacteria were isolated from these units while they were mounted on water distribution system in order to determine the variations in HPC and diversity of the bacterial population using polymerase chain reaction (PCR). Results showed that bacterial population regrowth in PoU units could increase HPC exceeding the limit of the 500 CFU/mL in outlet water. In around 70% of the input water samples, the HPC was less than 500 CFU/ml with a mean of 226.7 (CI 95%: 28.1–425.3). HPC in output treated water samples had an increasing trend from the start of the unit operation with a mean of 2416.4 (CI 95%: 1074.9–3757.9). Out of 49 detected bacterial strains, 20 strains were Gram-negative and 29 Gram-positive. Bacillus was the most frequent genes detected in inlet and outlet water samples. Most of the identified bacterial strains were opportunistic pathogens potentially dangerous for immunocompromised population. HPC population in PoU units significantly can be increased during a one-month period of operation, so replacement of the filters must be done regularly.

在伊朗西南部城市阿瓦士，大多数家庭都使用使用点 (PoU) 水处理装置。当这些单元安装在配水系统上时，从这些单元中分离出异养平板计数 (HPC) 细菌，以便使用聚合酶链式反应 (PCR) 确定 HPC 的变化和细菌种群的多样性。结果表明，以 PoU 为单位的细菌种群再生可以使 HPC 增加，超过出水中 500 CFU/mL 的限制。在大约 70% 的输入水样中，HPC 低于 500 CFU/ml，平均值为 226.7（CI 95%：28.1–425.3）。从装置运行开始，输出处理水样中的 HPC 呈增加趋势，平均值为 2416.4（CI 95%：1074.9–3757.9）。在检测到的 49 株细菌中，20 株为革兰氏阴性菌株，29 株为革兰氏阳性菌株。芽孢杆菌是进水和出水样品中检测到的最常见的基因。大多数已鉴定的细菌菌株都是机会性病原体，对免疫功能低下的人群具有潜在危险。在一个月的运行期间，PoU 单元中的 HPC 数量会显着增加，因此必须定期更换过滤器。