Table_1_Distribution of Beta-Lactamase Producing Gram-Negative Bacterial Isolates in Isabela River of Santo Domingo, Dominican Republic.XLSX

Bacteria carrying antibiotic resistance genes (ARGs) are naturally prevalent in lotic ecosystems such as rivers. Their ability to spread in anthropogenic waters could lead to the emergence of multidrug-resistant bacteria of clinical importance. For this study, three regions of the Isabela river, an important urban river in the city of Santo Domingo, were evaluated for the presence of ARGs. The Isabela river is surrounded by communities that do not have access to proper sewage systems; furthermore, water from this river is consumed daily for many activities, including recreation and sanitation. To assess the state of antibiotic resistance dissemination in the Isabela river, nine samples were collected from these three bluedistinct sites in June 2019 and isolates obtained from these sites were selected based on resistance to beta-lactams. Physico-chemical and microbiological parameters were in accordance with the Dominican legislation. Matrix-assisted laser desorption ionization-time of flight mass spectrometry analyses of ribosomal protein composition revealed a total of 8 different genera. Most common genera were as follows: Acinetobacter (44.6%) and Escherichia (18%). Twenty clinically important bacterial isolates were identified from urban regions of the river; these belonged to genera Escherichia (n = 9), Acinetobacter (n = 8), Enterobacter (n = 2), and Klebsiella (n = 1). Clinically important multi-resistant isolates were not obtained from rural areas. Fifteen isolates were selected for genome sequencing and analysis. Most isolates were resistant to at least three different families of antibiotics. Among beta-lactamase genes encountered, we found the presence of blaTEM, blaOXA, blaSHV, and blaKPC through both deep sequencing and PCR amplification. Bacteria found from genus Klebsiella and Enterobacter demonstrated ample repertoire of antibiotic resistance genes, including resistance from a family of last resort antibiotics reserved for dire infections: carbapenems. Some of the alleles found were KPC-3, OXA-1, OXA-72, OXA-132, CTX-M-55, CTX-M-15, and TEM-1.

携带抗生素耐药基因（antibiotic resistance genes, ARGs）的细菌在河流等流水生态系统中天然流行。这类细菌在受人类活动干扰的水体中传播的能力，可能引发具有临床重要性的多重耐药细菌出现。本研究针对圣多明各市的重要城市河流——伊莎贝拉河（Isabela River）的三个区域，开展了抗生素耐药基因检出情况的评估。伊莎贝拉河流经的社区均未配备完善的污水处理系统，且该河河水每日被用于休闲、卫生等诸多活动。为评估伊莎贝拉河的抗生素耐药性传播现状，研究团队于2019年6月从三处不同的采样点采集了9份样本，并基于对β-内酰胺类抗生素的耐药性，筛选自这些采样点的分离菌株。所有理化与微生物学参数均符合多米尼加共和国相关法规要求。通过对核糖体蛋白组成开展基质辅助激光解吸电离飞行时间质谱（matrix-assisted laser desorption ionization-time of flight mass spectrometry, MALDI-TOF MS）分析，共鉴定出8个不同菌属。占比最高的两个菌属分别为不动杆菌属（Acinetobacter，44.6%）与埃希氏菌属（Escherichia，18%）。从该河城区河段中共鉴定出20株具有临床重要性的分离菌株，分属于埃希氏菌属（n=9）、不动杆菌属（n=8）、肠杆菌属（n=2）与克雷伯菌属（n=1）。农村河段未分离得到具有临床重要性的多重耐药菌株。研究团队选取其中15株菌株进行基因组测序与相关分析。多数分离菌株对至少三类不同的抗生素家族表现出耐药性。在检出的β-内酰胺酶基因中，本研究通过深度测序与PCR扩增技术，均检测到blaTEM、blaOXA、blaSHV及blaKPC等基因。克雷伯菌属与肠杆菌属的细菌携带丰富的抗生素耐药基因谱，其中包含针对重症感染治疗的终极抗生素——碳青霉烯类（carbapenems）的耐药性。本次检出的部分等位基因为KPC-3、OXA-1、OXA-72、OXA-132、CTX-M-55、CTX-M-15及TEM-1。