Eguale Tadesse
Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
BMC Vet Res. 2018 Jul 6;14(1):217. doi: 10.1186/s12917-018-1539-4.
Poultry is one of the common sources of non-typhoidal Salmonella and poultry products are the major sources of human infection with non-typhoidal Salmonella. In spite of flourishing poultry industry in the country, data on prevalence and antimicrobial susceptibility of non-typhoidal Salmonella serovars at farm level is not available in Ethiopia. This study investigated prevalence, serotype distribution and antimicrobial resistance of non-typhoidal Salmonella in poultry farms in Addis Ababa and its surrounding districts.
A total of 549 fresh pool of fecal droppings (n = 3 each) were collected from 48 poultry farms and cultured for Salmonella using standard laboratory technique and serotyped using slide agglutination technique. Susceptibility of Salmonella isolates to18 antimicrobials was tested according to CLSI guideline using Kirby-Bauer disk diffusion assay. Salmonella was recovered in 7 (14.6%) of the farms and 26 (4.7%) of the samples. Salmonella was more common in poultry farms with larger flock size than in the smaller ones and in Ada'a district as compared to other districts. All isolates were obtained from farms containing layers. Two out of 6 (33.3%) farms that kept birds in cage were positive for Salmonella while only 5 (11.9%) of the 42 farms who used floor system were positive. Oxytetracycline was used widely in 40 (83.3%) of the farms, followed by amoxicillin 14 (29.2%) and sulfonamides 11 (22.9%). Salmonella Saintpaul was the dominant serotype detected accounting for 20 (76.9%) of all isolates. Other serovars, such as S. Typhimurium3 (11.5%), S. Kentucky 2 (7.7%) and S. Haifa 1 (3.8%) were also detected. Of all the Salmonella isolates tested, 24 (92.3%) were intermediately or fully resistant to sulfisoxazole and streptomycin, 12 (46.2%) to cephalothin, while 11 (42.3%) were resistant to ampicillin, amoxicillin+clavulanic acid, kanamycin and chloramphenicol. Multidrug resistance (MDR) to several drugs was common in S. Kentucky and S. Saintpaul.
Despite low prevalence of Salmonella in poultry farms in the study area, circulation of MDR strains in some farms warrant special biosecurity measures to hinder dissemination of these pathogens to other farms and the public. Moreover, awareness creation on prudent use of antimicrobials is recommended.
家禽是非伤寒沙门氏菌的常见来源之一，家禽产品是人类感染非伤寒沙门氏菌的主要来源。尽管该国的家禽业蓬勃发展，但埃塞俄比亚缺乏农场层面非伤寒沙门氏菌血清型的流行情况和抗菌药物敏感性数据。本研究调查了亚的斯亚贝巴及其周边地区家禽养殖场中非伤寒沙门氏菌的流行情况、血清型分布和抗菌药物耐药性。
从48个家禽养殖场共收集了549份新鲜粪便样本池（每个样本池3份粪便），采用标准实验室技术培养沙门氏菌，并使用玻片凝集技术进行血清分型。根据CLSI指南，采用 Kirby-Bauer 纸片扩散法检测沙门氏菌分离株对18种抗菌药物的敏感性。在7个（14.6%）养殖场和26个（4.7%）样本中检出沙门氏菌。沙门氏菌在鸡群规模较大的家禽养殖场比规模较小的养殖场更常见，在阿达阿区比其他区更常见。所有分离株均来自饲养蛋鸡的养殖场。在6个采用笼养方式养鸡的养殖场中，有2个（33.3%）沙门氏菌检测呈阳性，而在42个采用地面养殖系统的养殖场中，只有5个（11.9%）呈阳性。40个（83.3%）养殖场广泛使用土霉素，其次是阿莫西林14个（29.2%）和磺胺类药物11个（22.9%）。圣保罗沙门氏菌是检测到的主要血清型，占所有分离株的20个（76.9%）。还检测到其他血清型，如鼠伤寒沙门氏菌3个（11.5%）、肯塔基沙门氏菌2个（7.7%）和海法沙门氏菌1个（3.8%）。在所有检测的沙门氏菌分离株中，24个（92.3%）对磺胺异恶唑和链霉素呈中度或完全耐药，12个（46.2%）对头孢噻吩耐药，而11个（42.3%）对氨苄西林、阿莫西林+克拉维酸、卡那霉素和氯霉素耐药。肯塔基沙门氏菌和圣保罗沙门氏菌对几种药物的多重耐药（MDR）很常见。
尽管研究区域内家禽养殖场沙门氏菌的流行率较低，但一些养殖场中多重耐药菌株的传播需要采取特殊的生物安全措施，以防止这些病原体传播到其他养殖场和公众。此外，建议提高对抗菌药物谨慎使用的认识。
