Molecular epidemiology, characterization of virulence factors and antibiotic resistance profile of Streptococcus agalactiae isolated from dairy farms in China and Pakistan

作     者：Ambreen LEGHARI Shakeel Ahmed LAKHO Faiz Muhammad KHAND Khaliq ur Rehman BHUTTO Sameen Qayoom LONE Muhammad Tahir ALEEM Iqra BANO Muhammad Ali CHANDIO Jan Muhammad SHAH LIN Hui-xing FAN Hong-jie Ambreen LEGHARI;Shakeel Ahmed LAKHO;Faiz Muhammad KHAND;Khaliq ur Rehman BHUTTO;Sameen Qayoom LONE;Muhammad Tahir ALEEM;Iqra BANO;Muhammad Ali CHANDIO;Jan Muhammad SHAH;LIN Hui-xing;FAN Hong-jie

作者机构：MOE Joint International Research Laboratory of Animal Health and Food SafetyCollege of Veterinary MedicineNanjing Agricultural UniversityNanjing 210095P.R.China Shaheed Benazir Bhutto University of Veterinary and Animal SciencesSakrand 67210Pakistan Central Veterinary Diagnostic LaboratoryTando Jam 70050Pakistan Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and ZoonosesYangzhou UniversityYangzhou 225009P.R.China 

出 版 物：《Journal of Integrative Agriculture》 (农业科学学报（英文版）)

年 卷 期：2023年第22卷第5期

页      面：1514-1528页

核心收录：

学科分类：0710[理学-生物学] 090603[农学-临床兽医学] 0832[工学-食品科学与工程（可授工学、农学学位）] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 1004[医学-公共卫生与预防医学(可授医学、理学学位)] 0905[农学-畜牧学] 0906[农学-兽医学] 09[农学] 0901[农学-作物学] 0703[理学-化学] 0902[农学-园艺学] 0713[理学-生态学] 

基　　金：supported by the National Key Research and Development Program of China (2021YFD1800400) the National Natural Science Foundation of China (31872480) the Jiangsu Agriculture Science and Technology Innovation Fund of China (CX(19)2020) the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (PAPD) 

主　　题：Streptococcus agalactiae mastitis epidemiology virulence characterization antibiotic resistance 

摘      要：Streptococcus agalactiae is one of the most common pathogens that cause bovine mastitis worldwide. Identifying pathogen prevalence and virulence factors is critical for developing prevention and control approaches. Herein, 1 161 milk samples from various dairy farms in China(n=558) and Pakistan(n=603) were collected between 2019–2021 and were subjected to S. agalactiae isolation. Prevalence, serotyping, virulence genes, and antibiotic-resistant genes of S. agalactiae were evaluated by PCR assay. All isolates were characterized for haemolysis, biofilm production, cytotoxicity, adhesion, and invasion on bovine mammary epithelial cells. The prevalence of S. agalactiae-induced mastitis in cattle was found to be considerably higher in Pakistan than in China. Jiangsu and Sindh provinces had the highest area-wise prevalence in China and Pakistan, respectively. Serotypes Ia and II were prevalent in both countries, whereas serotype III was found only in Pakistan. Moreover, all isolates tested positive for PI-2b gene but negative for PI-1 and PI-2a genes. All isolates harboured cfb, cylE, hylB, and fbsB virulent genes, whereas many of them lacked bibA, rib and bca. However, the absence of bac and scp genes in Chinese isolates and cspA in Pakistani isolates was noted, while spb1 and lmb were not detected in isolates of both countries. Pakistani isolates, particularly serotype Iapositive, had a considerably higher ability to produce biofilm, haemolysis, cytotoxicity, adhesion, and invasion than Chinese isolates. Most of the isolates were phenotypically resistant to tetracycline, erythromycin, and clindamycin and genotypic resistance was confirmed by the presence of ermA, ermB, tetM and tetO genes. Our study highlights the antimicrobial resistance profile and virulence-related factors contributing to the epidemiological spread of mastitis-causing S. agalactiae in China and Pakistan. The findings may facilitate future studies designed to develop improved treatment and control str