Department of Microbiology, Government College University Faisalabad, Pakistan.
Biomed Res Int. 2022 Oct 5;2022:8224883. doi: 10.1155/2022/8224883. eCollection 2022.
The emergence of resistance to beta-lactam agents in poultry results in multidrug-resistant (MDR) phenotypes in isolates from poultry birds. The appearance of mobile colistin resistance () genes in the poultry sector has further worsened the situation. Therefore, the current study is aimed at investigating the molecular epidemiology of harboring colistin-resistant among poultry.
The isolation and identification of colistin-resistant (CR-Ec) were done from the broiler's fecal samples through culturing using selective media supplemented with colistin sulfate (4 g/ml). The antibiogram studies of the isolates were performed using the disc diffusion method and broth microdilution method as per CLSI guidelines. The screening for the genes conferring resistance to colistin as well as beta-lactam agents was performed by PCR. The genetic diversity of positive strains was assessed by multilocus sequencing typing (MLST).
Out of 500 fecal samples, 7% (35/500) were found positive for the presence of colistin-resistant (CR-Ec). Among the CR-Ec isolates, 74.28% (26/35) were detected as ESBL producers carrying the CTX-M-1 gene in 15/35 (42.85%) isolates and CTX-M-15 and TEM genes in 21/35 (60%) and 35/35 (100%) isolates, respectively. isolates were found positive for the presence of -1, although none of the isolates exhibited the -2 or -3 genes. The MLST of CR-Ec has shown the ST1035 as the most prevalent genotype, while 82.85% (29/35) of CR-Ec strains belonged to clonal complex (CC) 131 comprising ST1035, ST131, ST1215, ST1650, and ST2279.
The findings suggest a continuous monitoring system in veterinary and clinical settings to avoid unnecessary antibiotics. Further studies are needed at the national level to help control the increasing resistance among Enterobacterales in poultry settings.
禽源分离株中β-内酰胺类耐药（MDR）表型的出现是由于对β-内酰胺类药物产生耐药性，而多药耐药（MDR）表型的出现则是由于对β-内酰胺类药物产生耐药性。在禽业中出现的移动性粘菌素耐药（）基因进一步恶化了这种情况。因此，本研究旨在调查禽源携带粘菌素耐药的 （CR-Ec）的分子流行病学。
通过在含有硫酸粘菌素（4μg/ml）的选择性培养基中培养，从肉鸡粪便样本中分离和鉴定耐粘菌素的 （CR-Ec）。根据 CLSI 指南，采用纸片扩散法和肉汤微量稀释法对分离株进行药敏试验。采用 PCR 法筛选对粘菌素和β-内酰胺类药物耐药的基因。采用多位点序列分型（MLST）法评估阳性菌株的遗传多样性。
在 500 份粪便样本中，有 7%（35/500）的样本中存在耐粘菌素的 （CR-Ec）。在 CR-Ec 分离株中，74.28%（26/35）为产 ESBL 株，携带 CTX-M-1 基因的分离株占 15/35（42.85%），携带 CTX-M-15 和 TEM 基因的分离株分别占 21/35（60%）和 35/35（100%）。有 71.43%（25/35）的 分离株被检测到携带 -1 基因，尽管没有分离株显示 -2 或 -3 基因。CR-Ec 的 MLST 显示 ST1035 是最常见的基因型，而 82.85%（29/35）的 CR-Ec 菌株属于包含 ST1035、ST131、ST1215、ST1650 和 ST2279 的克隆群（CC）131。
这些发现表明，在兽医和临床环境中需要建立一个持续的监测系统，以避免不必要的抗生素使用。需要在国家层面开展进一步的研究，以帮助控制禽源肠杆菌科耐药性的不断增加。
