發(fā)布者：抗性基因網(wǎng) 時間：2023-06-12 瀏覽量：351
摘要
? ? ? 腸桿菌中超廣譜β-內(nèi)酰胺酶（ESBL）的出現(xiàn)，尤其是碳青霉烯酶的出現(xiàn)，導致治療選擇有限。因此，充分了解所有潛在的傳播途徑至關(guān)重要，尤其是在醫(yī)院廢水等高風險來源。本研究旨在量化四種腸道機會性病原體（EOPs），即總大腸桿菌、ESBL和碳青霉烯類耐藥大腸桿菌及其相應的耐藥基因（兩種ESBL和五種碳青霉烯酶基因），并對薩格勒布兩家大型醫(yī)院兩個季節(jié)的醫(yī)院廢水中的腸道細菌分離株進行鑒定。培養(yǎng)顯示，總大腸菌群和耐碳青霉烯類大腸菌群的平均水平相似（3.4×104 CFU/mL），推定ESBL大腸菌群水平低10倍（3×103 CFU/mL）。實時PCR顯示，在所檢測的所有抗性基因中，EOP中的大腸桿菌水平最高（105個細胞當量/mL），blaKPC基因水平最高（高達10?1個基因拷貝/16S個拷貝）。從醫(yī)院廢水中分離出的69株產(chǎn)ESBL和90株產(chǎn)碳青霉烯酶的腸桿菌（CPE）中，所有菌株都具有多重耐藥性，大多數(shù)被鑒定為大腸桿菌、檸檬酸桿菌、腸桿菌和克雷伯菌。在ESBL分離株中，blaCTX-M-15是最常見的ESBL基因，而在CPE分離株中中，blaKPC-2和blaNDM-1是最常檢測到的CP基因，其次是blaOXA-48。使用PFGE、MLST和全基因組測序（WGS）的分子流行病學顯示，臨床相關(guān)變體，如大腸桿菌ST131（blaCTX-M-15/blaTEM-116）和ST541（blaKPC-2）、肺炎克雷伯菌ST101（blaOXA-48/blaNDM-1）和陰溝腸桿菌復合物ST277（blaKPC-2/blaNDM-1）是最常檢測到的克隆類型。WGS還揭示了這些和其他分離株中各種各樣的抗性基因和質(zhì)粒，以及blaCTX-M、blaOXA-48和blaKPC-2基因側(cè)翼區(qū)域的轉(zhuǎn)座子和插入序列，表明了動員的潛力。我們得出的結(jié)論是，醫(yī)院廢水是臨床上重要病原體和耐藥基因的潛在二級庫，因此在排入城市下水道系統(tǒng)之前需要進行有效的預處理。
Abstract
The emergence of extended-spectrum β-lactamase (ESBL)- and especially carbapenemases in Enterobacterales has led to limited therapeutic options. Therefore, it is critical to fully understand all potential routes of transmission, especially in high-risk sources such as hospital wastewater. This study aimed to quantify four enteric opportunistic pathogens (EOPs), total, ESBL- and carbapenem-resistant coliforms and their corresponding resistance genes (two ESBL and five carbapenemase genes) and to characterize enterobacterial isolates from hospital wastewater from two large hospitals in Zagreb over two seasons. Culturing revealed similar average levels of total and carbapenem-resistant coliforms (3.4 × 104 CFU/mL), and 10-fold lower levels of presumptive ESBL coliforms (3 × 103 CFU/mL). Real-time PCR revealed the highest E. coli levels among EOPs (105 cell equivalents/mL) and the highest levels of the blaKPC gene (up to 10?1 gene copies/16S copies) among all resistance genes examined. Of the 69 ESBL- and 90 carbapenemase-producing Enterobacterales (CPE) isolates from hospital wastewater, all were multidrug-resistant and most were identified as Escherichia coli, Citrobacter, Enterobacter, and Klebsiella. Among ESBL isolates, blaCTX-M-15 was the most prevalent ESBL gene, whereas in CPE isolates, blaKPC-2 and blaNDM-1 were the most frequently detected CP genes, followed by blaOXA-48. Molecular epidemiology using PFGE, MLST and whole-genome sequencing (WGS) revealed that clinically relevant variants such as E. coli ST131 (blaCTX-M-15/blaTEM-116) and ST541 (blaKPC-2), K. pneumoniae ST101 (blaOXA-48/blaNDM-1), and Enterobacter cloacae complex ST277 (blaKPC-2/blaNDM-1) were among the most frequently detected clone types. WGS also revealed a diverse range of resistance genes and plasmids in these and other isolates, as well as transposons and insertion sequences in the flanking regions of the blaCTX-M, blaOXA-48, and blaKPC-2 genes, suggesting the potential for mobilization. We conclude that hospital wastewater is a potential secondary reservoir of clinically important pathogens and resistance genes and therefore requires effective pretreatment before discharge to the municipal sewer system.
https://www.sciencedirect.com/science/article/abs/pii/S0048969723004205