Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
Department of Medical, Oral and Biotechnological Sciences, and Center of Excellence on Aging and Translational Medicine (CeSI-MeT), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy.
Microb Drug Resist. 2019 Sep;25(7):1041-1049. doi: 10.1089/mdr.2019.0016. Epub 2019 Apr 17.
The main goal of this study was to identify Gram-negative bacteria resistant to antibiotics, in particular β-lactams, in stream waters and effluents from urban wastewater treatment plants draining into Fino, Tavo, and Saline rivers of the Abruzzo region, Italy. Eight sampling sites were selected because they were the most contaminated by coliforms during previous sampling campaign. One sample for each site was collected for the detection of total and fecal coliforms, and species by Colilert-18 and Enterolert-E Quanti-Tray/2000. Antibiotic-resistant bacteria, selected on ampicillin and cefotaxime-supplemented agar plates, were identified by EnteroPluri test systems and then confirmed by MALDI-TOF. The resistant determinants were identified and characterized by PCR and sequencing. The microbiological analysis allowed to detect , total coliforms, fecal coliforms, and enterococci with a coefficient of variation of 215.7%, 212.8%, 242.5%, and 188.5%, respectively. Several Gram-negative bacteria were identified: , , , , , , , , and . All strains possessed class 1 integrons, insertion sequences, and genes encoding for serin- and metallo-β-lactamases. Extended-spectrum β-lactamases, such as CTX-M-15 and CTX-M-27, were found in Enterobacteriaceae, whereas CphA metallo-β-lactamase was found in and . The main resistance's mechanism to β-lactams observed among the analyzed strains is represented by the production of serin β-lactamases (CTX-M-15, CTX-M-27, and SHV-1) and metallo β-lactamase (CphA).
本研究的主要目的是在意大利阿布鲁佐地区的菲诺（Fino）、塔沃（Tavo）和盐水（Saline）河流的溪流和城市污水处理厂废水中，鉴定出对抗生素（尤其是β-内酰胺类抗生素）具有耐药性的革兰氏阴性细菌。选择了八个采样点，因为在之前的采样活动中，这些采样点受大肠菌群污染最为严重。每个采样点采集一个样本，用于检测总大肠菌群和粪大肠菌群，并通过 Colilert-18 和 Enterolert-E Quanti-Tray/2000 检测 种。在添加氨苄青霉素和头孢噻肟的琼脂平板上选择抗生素耐药细菌，然后通过 EnteroPluri 测试系统进行鉴定，最后通过 MALDI-TOF 进行确认。通过 PCR 和测序鉴定和表征耐药决定因素。微生物分析检测到总大肠菌群、粪大肠菌群和肠球菌，变异系数分别为 215.7%、212.8%、242.5%和 188.5%。鉴定出几种革兰氏阴性细菌，包括 、 、 、 、 、 、 和 。所有菌株均携带 1 类整合子、插入序列和编码丝氨酸和金属β-内酰胺酶的基因。在肠杆菌科中发现了超广谱β-内酰胺酶，如 CTX-M-15 和 CTX-M-27，而 CphA 金属β-内酰胺酶则存在于 和 中。在所分析的菌株中，β-内酰胺类抗生素的主要耐药机制是丝氨酸β-内酰胺酶（CTX-M-15、CTX-M-27 和 SHV-1）和金属β-内酰胺酶（CphA）的产生。
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