Mwambene Saxon J, Mtenga Adelard B, Chengula Augustino A, Hoza Abubakar S
Tanzania Medicines and Medical Devices Authority, P.O. Box 77150, DSM, Tanzania.
Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P.O. Box 3019, Morogoro, Tanzania.
Access Microbiol. 2025 May 21;7(5). doi: 10.1099/acmi.0.000879.v5. eCollection 2025.
is one of the most prevalent foodborne bacteria, posing a significant global health concern and responsible for ~155,000 deaths and 93.8 million human foodborne illnesses annually. The rampant use of antibiotic agents to combat salmonellosis in poultry has contributed to the emergence of resistance against commonly used antibiotics. The cross-sectional study was conducted between January and June 2023 across three districts in the Dar es Salaam region, Tanzania. isolates were detected and confirmed by using standard microbiological conventional methods and molecular methods such as PCR and genomic sequencing. PCR was used for detecting the presence of the gene, and partial DNA sequencing was performed to identify species and their close relatedness. A Kirby-Bauer disc diffusion method was employed to evaluate sensitivity to seven different commonly used antibiotics, namely ampicillin, azithromycin, chloramphenicol, ciprofloxacin, gentamycin, trimethoprim/sulfamethoxazole and tetracycline. strain with reference number ATCC 8739 was used as a control. The overall isolates from faecal droppings were 6.04% (=796). Of the PCR-confirmed isolates, 64.3% (=28) were resistant to more than two classes of antibiotics and hence considered multidrug resistant. The highest resistance was observed with ampicillin (92.9%, =26), followed by tetracycline (71.43%, =20), ciprofloxacin (42.9%, =12), sulphonamide (42.85%, =12), gentamicin (35.7%, =10) and azithromycin (28.9%, =8). All the isolates were susceptible to chloramphenicol (100%, =28). Twenty-eight isolates were sent for sequencing, out of which 16 sequences (OR021717-OR021739) met the criteria for phylogenetic analysis. All 16 sequences had a per cent identity to EU348369 strains Senftenberg isolated from China, OL581594 Newport isolated from China and EU348368 Pullorum isolates from China. Other sequences diverged more distantly; these are Abony with accession number CP007541 and Kentucky with accession number OL581592. The tree also included an outgroup species, , which was downloaded from GenBank with accession numbers NC015761 and NC021870 . The high level of antibiotic resistance found in this study could be due to the misuse of antibiotics in poultry management, and/or, probably, there were circulating resistant strains in the environment. To reverse the trend observed, immediate interventions such as advocating for the prudent use of antibiotics in poultry production systems by strengthening extension services to poultry farmers and the use of a farmer field school model to improve poultry management through improved farm biosecurity are required.
是最常见的食源细菌之一，在全球范围内对健康构成重大威胁，每年导致约15.5万人死亡和9380万例食源性疾病。在家禽中大量使用抗生素来对抗沙门氏菌病导致了对常用抗生素的耐药性出现。这项横断面研究于2023年1月至6月在坦桑尼亚达累斯萨拉姆地区的三个区进行。通过使用标准微生物学常规方法和分子方法（如PCR和基因组测序）检测和确认分离株。PCR用于检测基因的存在，并进行部分DNA测序以鉴定物种及其亲缘关系。采用 Kirby-Bauer 纸片扩散法评估对七种不同常用抗生素的敏感性，即氨苄西林、阿奇霉素、氯霉素、环丙沙星、庆大霉素、甲氧苄啶/磺胺甲恶唑和四环素。参考编号为ATCC 8739的菌株用作对照。粪便样本中的分离株总体比例为6.04%（=796株）。在经PCR确认的分离株中，64.3%（=28株）对两类以上抗生素耐药，因此被视为多重耐药。对氨苄西林的耐药率最高（92.9%，=26株），其次是四环素（71.43%，=20株）、环丙沙星（42.9%，=12株）、磺胺类药物（42.85%，=12株）、庆大霉素（35.7%，=10株）和阿奇霉素（28.9%，=8株）。所有分离株对氯霉素均敏感（100%，=28株）。28株分离株送去测序，其中16个序列（OR021717 - OR021739）符合系统发育分析标准。所有16个序列与从中国分离的EU348369 森弗滕贝格菌株、从中国分离的OL581594 纽波特菌株以及从中国分离的EU348368 鸡白痢分离株具有相同的百分比同一性。其他序列差异较大；这些是登录号为CP007541的阿博尼菌株和登录号为OL581592的肯塔基菌株。该树还包括一个外群物种，其从GenBank下载，登录号为NC015761和NC021870 。本研究中发现的高水平抗生素耐药性可能是由于家禽管理中抗生素的滥用，和/或环境中可能存在传播的耐药菌株。为扭转观察到的趋势，需要立即采取干预措施，例如通过加强对家禽养殖户的推广服务，倡导在家禽生产系统中谨慎使用抗生素，并采用农民田间学校模式，通过改善农场生物安全来改善家禽管理。
