Local data from the Asella Teaching and Referral Hospital in the town of Asella, Ethiopia reveal a high prevalence of extended-spectrum β-lactamase- (ESBL) producing Gram-negative bacteria (GNB) in clinical isolates. To investigate a possible route of transmission, we determined the proportions ESBL-producing GNB in isolates from flies caught in the hospital and in the town of Asella. Flies were collected in August 2019 from the neonatal intensive care unit (NICU), the orthopedic ward, the hospital’s waste disposal area, and from a butchery situated 1.5 km from the hospital. After trapping, the flies were macerated and suspended in sterile normal saline. The suspensions were inoculated on MacConkey agar and incubated overnight. Species identification and antimicrobial susceptibility testing were performed using Vitek®-MS and VITEK® 2. In total, 103 bacterial isolates were obtained from 85 flies (NICU: 11 isolates from 20 flies, orthopedic ward: 10 isolates from 12 flies, waste disposal area: 37 isolates from 26 flies, butchery: 45 isolates from 27 flies). The proportions of ESBL-producing bacteria among isolates obtained from flies collected in the hospital compound were significantly higher (82%, 90%, and 57% in NICU, orthopedic ward and waste disposal area, respectively) compared to flies collected outside of the hospital compound (2% (@1/45) in the butchery) (p ≤ 0.001). The proportion of ESBL was 67% (6/9) among Raoultella spp. 67% (4/6) among Kluyvera spp., 56% (5/9) among Enterobacter spp., 50% (5/10) among E. coli, and 44% (8/18) among Klebsiella spp.. Of the 40 ESBL-genes detected, 85% were CTX-M-like, 83% TEM-like, 23% SHV-like, and 2% CTX-M-2-like. ESBL-producing bacteria showed higher rates of resistance against ciprofloxacin (66% vs. 5%), gentamicin (68% vs. 3%), piperacillin-tazobactam (78% vs. 5%), and trimethoprim-sulfamethoxazole (88% vs. 16%), compared to non-ESBL-producing bacteria. A high proportion of ESBL was identified in isolates from flies caught in the hospital compound compared with isolates of flies collected at a distance of 1.5 km from the hospital. Flies can be potential vectors for transmission of multidrug-resistant (MDR) bacteria within hospitals. Further studies are needed to determine the source of MDR colonization in flies and possible impact of MDR for nosocomial infections.

中文翻译：

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埃塞俄比亚一家医院及其郊区捕获的苍蝇携带产ESBL的革兰氏阴性菌

来自埃塞俄比亚阿塞拉镇阿塞拉教学和转诊医院的当地数据显示，临床分离株中产生超广谱 β-内酰胺酶 (ESBL) 的革兰氏阴性菌 (GNB) 的患病率很高。为了调查可能的传播途径，我们确定了医院和阿塞拉镇捕获的苍蝇分离株中产生 ESBL 的 GNB 比例。2019 年 8 月，我们从新生儿重症监护病房 (NICU)、骨科病房、医院废物处理区以及距离医院 1.5 公里的一家屠宰场收集了苍蝇。捕获后，将果蝇浸渍并悬浮在无菌生理盐水中。将悬浮液接种在麦康凯琼脂上并孵育过夜。使用 Vitek®-MS 和 VITEK® 2 进行菌种鉴定和药敏测试。​​总共从 85 只苍蝇中分离出 103 株细菌（新生儿重症监护病房：20 只苍蝇中分离出 11 株，骨科病房：12 只苍蝇中分离出 10 株，废物处理区） ：从 26 只苍蝇中分离出 37 个分离株，屠宰：从 27 只苍蝇中分离出 45 个分离株）。与在医院外收集的苍蝇相比，从医院院内收集的苍蝇中获得的分离株中产 ESBL 的比例显着较高（新生儿重症监护病房、骨科病房和废物处理区分别为 82%、90% 和 57%）化合物（屠宰场中的 2% (@1/45)）（p ≤ 0.001）。Raoultella spp中ESBL的比例为67%（6/9）。克鲁维拉属 67% (4/6)、肠杆菌属 56% (5/9)、大肠杆菌 50% (5/10)、克雷伯氏菌 44% (8/18)。检测到的 40 个 ESBL 基因中，85% 为 CTX-M 样，83% 为 TEM 样，23% 为 SHV 样，2% 为 CTX-M-2 样。产 ESBL 细菌对环丙沙星（66% vs. 5%）、庆大霉素（68% vs. 3%）、哌拉西林-他唑巴坦（78% vs. 5%）和甲氧苄啶-磺胺甲恶唑（88% vs. . 16%)，与不产生 ESBL 的细菌相比。与在距离医院 1.5 公里处收集的苍蝇分离株相比，在医院院落捕获的苍蝇分离株中发现了较高比例的 ESBL。苍蝇可能是医院内传播多重耐药 (MDR) 细菌的潜在媒介。需要进一步的研究来确定果蝇中耐多药定植的来源以及耐多药对医院感染的可能影响。