Institute for Water and Wastewater Technology, Durban University of Technology, Kwa-Zulu Natal 4001, Durban, South Africa.
Environ Monit Assess. 2021 Apr 24;193(5):294. doi: 10.1007/s10661-021-09046-6.
Aquatic environments are hotspots for the spread of antibiotic-resistant bacteria and genes due to pollution caused mainly by anthropogenic activities. The aim of this study was to evaluate the impact of wastewater effluents, informal settlements, hospital, and veterinary clinic discharges on the occurrence, antibiotic resistance profile and virulence signatures of Aeromonas spp. and Pseudomonas spp. isolated from surface water and wastewater. High counts of Aeromonas spp. (2.5 (± 0.8) - 3.3 (± 0.4) log CFU mL) and Pseudomonas spp. (0.6 (± 1.0) - 1.8 (± 1.0) log CFU mL) were obtained. Polymerase chain reaction (PCR) and MALDI-TOF characterization identified four species of Aeromonas and five of Pseudomonas. The isolates displayed resistance to 3 or more antibiotics (71% of Aeromonas and 94% of Pseudomonas). Aeromonas spp. showed significant association with the antibiotic meropenem (χ = 3.993, P < 0.05). The virulence gene aer in Aeromonas was found to be positively associated with the antibiotic resistance gene blaOXA (χ = 6.657, P < 0.05) and the antibiotic ceftazidime (χ = 7.537, P < 0.05). Aeromonas recovered from both wastewater and surface water displayed high resistance to ampicillin and had higher multiple antibiotic resistance (MAR) indices close to the hospital. Pseudomonas isolates on the other hand exhibited low resistance to carbapenems but very high resistance to the third-generation cephalosporins and cefixime. The results showed that some of the Pseudomonas spp. and Aeromonas spp. isolates were extended-spectrum β-lactamase producing bacteria. In conclusion, the strong association between virulence genes and antibiotic resistance in the isolates shows the potential health risk to communities through direct and indirect exposure to the water.
水生环境是抗生素耐药菌和基因传播的热点，主要是由于人为活动造成的污染。本研究旨在评估废水、非正规住区、医院和兽医诊所排放对从地表水和废水中分离出的气单胞菌和假单胞菌的发生、抗生素耐药谱和毒力特征的影响。获得了高计数的气单胞菌（2.5（±0.8）-3.3（±0.4）log CFU mL）和假单胞菌（0.6（±1.0）-1.8（±1.0）log CFU mL）。聚合酶链反应（PCR）和 MALDI-TOF 鉴定出四种气单胞菌和五种假单胞菌。这些分离株对 3 种或更多抗生素表现出耐药性（71%的气单胞菌和 94%的假单胞菌）。气单胞菌与抗生素美罗培南显著相关（χ²=3.993，P<0.05）。在气单胞菌中发现毒力基因 aer 与抗生素耐药基因 blaOXA （χ²=6.657，P<0.05）和抗生素头孢他啶呈正相关（χ²=7.537，P<0.05）。从废水和地表水回收的气单胞菌均对氨苄西林表现出高耐药性，且多重抗生素耐药性（MAR）指数接近医院。另一方面，假单胞菌分离株对碳青霉烯类抗生素的耐药性较低，但对第三代头孢菌素和头孢克肟的耐药性很高。结果表明，一些假单胞菌和气单胞菌分离株是产超广谱β-内酰胺酶的细菌。综上所述，分离株中毒力基因与抗生素耐药性之间的强相关性表明，通过直接和间接接触水，对社区存在潜在的健康风险。
