Pseudomonas aeruginosa (P. aeruginosa) is one of the most serious pathogens implicated in antimicrobial resistance, and it has been identified as an ESKAPE along with other extremely significant multidrug resistance pathogens. The present study was carried out to explore prevalence, antibiotic susceptibility phenotypes, virulence-associated genes, integron (int1), colistin (mcr-1), and β-lactamase resistance' genes (ESBls), as well as biofilm profiling of P. aeruginosa isolated from broiler chicks and dead in-shell chicks. A total of 300 samples from broiler chicks (n = 200) and dead in-shell chicks (n = 100) collected from different farms and hatcheries located at Mansoura, Dakahlia Governorate, Egypt were included in this study. Bacteriological examination was performed by cultivation of the samples on the surface of both Cetrimide and MacConkey’s agar. Presumptive colonies were then subjected to biochemical tests and Polymerase Chain Reaction (PCR) targeting 16S rRNA. The recovered isolates were tested for the presence of three selected virulence-associated genes (lasB, toxA, and exoS). Furthermore, the retrieved isolates were subjected to phenotypic antimicrobial susceptibility testing by Kirby–Bauer disc diffusion method as well as phenotypic detection of ESBLs by both Double Disc Synergy Test (DDST) and the Phenotypic Confirmatory Disc Diffusion Test (PCDDT). P. aeruginosa isolates were then tested for the presence of antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, OXA-2, VEB-1, SHV, TEM, and CTX-M). Additionally, biofilm production was examined by the Tube Adherent method (TA) and Microtiter Plate assay (MTP). Fifty –five isolates were confirmed to be P. aeruginosa, including 35 isolates from broiler chicks and 20 isolates from dead in-shell chicks. The three tested virulence genes (lasB, toxA, and exoS) were detected in all isolates. Antibiogram results showed complete resistance against penicillin, amoxicillin, ceftriaxone, ceftazidime, streptomycin, erythromycin, spectinomycin, and doxycycline, while a higher sensitivity was observed against meropenem, imipenem, colistin sulfate, ciprofloxacin, and gentamicin. ESBL production was confirmed in 12 (21.8%) and 15 (27.3%) isolates by DDST and PCDDT, respectively. Antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, SHV, TEM, and CTX-M), were detected in 87.3%, 18.2%, 16.4%, 69.1%, 72.7%, and 54.5% of the examined isolates respectively, whereas no isolate harbored the OXA-2 or VEB-1 genes. Based on the results of both methods used for detection of biofilm formation, Kappa statistics [kappa 0.324] revealed a poor agreement between both methods. the emergence of mcr-1 and its coexistence with other resistance genes such as β-lactamase genes, particularly blaOXA-10, for the first time in P. aeruginosa from young broiler chicks and dead in-shell chicks in Egypt pose a risk not only to the poultry industry but also to public health.

中文翻译：

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mcr-1 和 β-内酰胺酶基因在铜绿假单胞菌中的传播：肉鸡和死壳鸡感染中 MDR 菌株的分子特征

铜绿假单胞菌 (P. aeruginosa) 是与抗菌素耐药性相关的最严重的病原体之一，它与其他极其重要的多重耐药病原体一起被确定为 ESKAPE。本研究旨在探讨疟原虫的患病率、抗生素敏感性表型、毒力相关基因、整合子 (int1)、粘菌素 (mcr-1) 和 β-内酰胺酶抗性基因 (ESBls) 以及生物膜分析。从肉鸡和死带壳雏鸡中分离出铜绿假单胞菌。本研究共收集了 300 个来自埃及达卡利亚省曼苏拉不同农场和孵化场的肉鸡 (n = 200) 和死带壳雏鸡 (n = 100) 样本。通过在西曲溴铵和麦康凯琼脂表面培养样品来进行细菌学检查。然后对假定的菌落进行生化测试和针对 16S rRNA 的聚合酶链反应 (PCR)。测试回收的分离株是否存在三种选定的毒力相关基因（lasB、toxA 和 exoS）。此外，对回收的分离株采用柯比-鲍尔纸片扩散法进行表型抗菌药物敏感性测试，并通过双纸片协同试验（DDST）和表型确认纸片扩散试验（PCDDT）对ESBL进行表型检测。然后测试铜绿假单胞菌分离株是否存在抗生素抗性基因 (ARG)：int1、mcr-1 和 ESBL 基因（OXA-10、OXA-2、VEB-1、SHV、TEM 和 CTX-M）。此外，通过管粘附法（TA）和微量滴定板测定（MTP）检查生物膜的产生。55 株被确认为铜绿假单胞菌，其中 35 株来自肉鸡，20 株来自死壳雏鸡。在所有分离株中均检测到了三个测试毒力基因（lasB、toxA 和 exoS）。抗菌谱结果显示对青霉素、阿莫西林、头孢曲松、头孢他啶、链霉素、红霉素、大观霉素和强力霉素完全耐药，而对美罗培南、亚胺培南、硫酸粘菌素、环丙沙星和庆大霉素则具有较高的敏感性。通过 DDST 和 PCDDT 分别确认 12 个（21.8%）和 15 个（27.3%）分离株产生 ESBL。抗生素抗性基因 (ARG)：int1、mcr-1 和 ESBL 基因（OXA-10、SHV、TEM 和 CTX-M）的检出率分别为 87.3%、18.2%、16.4%、69.1%、72.7% 和分别有 54.5% 的检查分离株含有 OXA-2 或 VEB-1 基因，而没有分离株含有 OXA-2 或 VEB-1 基因。根据两种用于检测生物膜形成的方法的结果，Kappa 统计数据 [kappa 0.324] 显示两种方法之间的一致性较差。mcr-1 的出现及其与其他抗性基因（如 β-内酰胺酶基因，特别是 blaOXA-10）的共存，首次出现在来自埃及幼雏肉鸡和死壳雏鸡的铜绿假单胞菌中，这不仅带来了风险对家禽业也对公众健康有利。