Environmental Microbiology and Biotechnology Laboratory, Department of Microbiology, University of Ibadan, Ibadan, Oyo State, Nigeria.
Molecular Biology and Biotechnology Laboratory, Department of Microbiology, University of Ibadan, Ibadan, Oyo State, Nigeria.
BMC Microbiol. 2024 Aug 20;24(1):308. doi: 10.1186/s12866-024-03444-9.
Dumpsites generate leachates containing bacteria that may carry antibiotic resistance genes, such as extended spectrum β-lactamase (ESBL). However, the contribution of dumpsite leachates in the environmental spread of ESBL genes has not been investigated in greater detail. This study aimed to quantify the impact of Ajakanga dumpsite leachate on the spread of ESBL genes through surface water. The susceptibility of Escherichia coli isolated from dumpsite leachate and the accompanying surface water to selected antibiotics was assessed by the standardized disc diffusion method. The isolates were evaluated for phenotypic ESBL production using the double disc synergy test (DDST). The detection of ESBL genes in the isolates was carried out using a primer-specific polymerase chain reaction (PCR). Escherichia coli isolates from leachate (n = 26/32) and surface water (n = 9/12) expressed ESBL phenotype. The ESBL-producing isolates showed the highest level of resistance to the 3rd generation cephalosporin antibiotics: cefotaxime (100%), cefpodoxime (97%), ceftazidime (97%), with low resistance observed to imipenem (6%) and azithromycin (3%). All the isolates were multidrug-resistant, showing resistance to three or more classes of antibiotics. All the ESBL-producing E. coli obtained carried bla, 21/35 (60%) carried bla while none of the isolates bore bla. This study found that ESBL-producing Escherichia coli from dumpsite leachate and nearby surface water had identical resistance signatures indicating the relatedness of the isolates, and that dumpsite leachate could contribute to the transfer of ESBL-producing bacteria and their genes to receiving surface water. This study has necessitated the need for a review of the guidelines and operational procedures of dumpsites to forestall a potential public health challenge.
垃圾填埋场会产生渗滤液，其中可能含有携带抗生素耐药基因的细菌，例如扩展谱β-内酰胺酶（ESBL）。然而，垃圾填埋场渗滤液对 ESBL 基因在环境中传播的贡献尚未进行更详细的研究。本研究旨在定量评估阿贾坎加垃圾填埋场渗滤液对通过地表水传播 ESBL 基因的影响。通过标准化圆盘扩散法评估从垃圾填埋场渗滤液和伴随的地表水分离的大肠杆菌对所选抗生素的敏感性。使用双圆盘协同试验（DDST）评估分离株的表型 ESBL 产生情况。使用引物特异性聚合酶链反应（PCR）检测分离株中的 ESBL 基因。从渗滤液（n=26/32）和地表水（n=9/12）中分离的大肠杆菌表现出 ESBL 表型。产 ESBL 的分离株对第三代头孢菌素类抗生素表现出最高水平的耐药性：头孢噻肟（100%）、头孢泊肟（97%）、头孢他啶（97%），对亚胺培南（6%）和阿奇霉素（3%）的耐药性较低。所有分离株均为多药耐药株，对三种或更多类别的抗生素表现出耐药性。所有获得的产 ESBL 大肠杆菌均携带 bla ，21/35（60%）携带 bla ，而没有分离株携带 bla 。本研究发现，来自垃圾填埋场渗滤液和附近地表水的产 ESBL 大肠杆菌具有相同的耐药特征，表明分离株具有相关性，并且垃圾填埋场渗滤液可能有助于产 ESBL 细菌及其基因转移到受纳地表水。本研究需要审查垃圾填埋场的指导方针和操作程序，以防止潜在的公共卫生挑战。
