Detail Abstract

Detection and Identification of Antibiotic-Resistant Bacteria in Tonle Sap Lake, Tonle Sap River, Mekong River, and Wastewater

Abstract

Antibiotics are medicines used to treat bacterial infections. Antibiotic resistance occurs when these medicines are not effective against the bacteria. This leads to higher medical costs, prolonged hospital stays and increased mortality. The current situation of antibiotic-resistant bacteria in the lake, rivers and wastewater in Cambodia has not yet been conducted so far. Therefore, the aim of this study was to detect and identify of antibiotic- resistant bacteria in Tole Sap Lake (TSL), Tonle Sap River (TSR), Mekong River (MR), and Wastewater (WW) in Phnom Penh (PP).  For TSL, the floating villages around Tonle Sap Lake (TSL) such as Chhnok Trou, Phat Sornday, Prek Khscah, Kompong Loung, Kompong Plouk, Chong Khnas, Kbal Tor, and Kaoh Chiveang in Kampong Chhang, Kampong Thom, Pursat, Siem Reap, and Battambang provinces were investigated respectively. The concentrations of ARB in dry season (November to April) for both Phnom Penh sites and floating villages of TSL in March were detected by using R2A solid medium with the presence of antibiotics.  Moreover, the colonies from antibiotic plates were isolated for multidrug-resistant (MDR) bacteria by disc diffusion method on Müeller-Hinton Agar. Furthermore, for some isolated strains of multidrug-resistant bacteria, DNA extraction, polymerase chain reaction amplifying, and gel electrophoresis were conducted in order to identify the bacterial strains by 16S gene rRNA sequencing in Japan. The results showed that for Phnom Penh site, the concentration of ARB in WW was the highest, followed by TSR and MR, respectively. Meanwhile, the ARB concentration in April was higher than other months. For floating villages in TSL, it is illustrated that the highest concentrations of ARB were in Kompong Loung and Kompong Phluk. Likewise, the concentrations of MDR bacteria were high for all sites, which range from 40% to 62%. The identification of MDR bacteria by 16S gene rRNA showed the presence of pathogenic bacteria, which are harmful and cause many serious infections, especially Stenotrophomonas maltophilia. Moreover, these bacteria were resistant to at least 4 types of antibiotics already.