Abstract
Streptococcus suis serotype 2 is an important zoonotic pathogen. Antimicrobial resistance phenotypes and genotypic characterizations of S. suis 2 from carrier sows and diseased pigs remain largely unknown. In this study, 96 swine S. suis type 2, 62 from healthy sows and 34 from diseased pigs, were analyzed. High frequency of tetracycline resistance was observed, followed by sulfonamides. The lowest resistance of S. suis 2 for β-lactams supports their use as the primary antibiotics to treat the infection of serotype 2. In contrast, 35 of 37 S. suis 2 with MLSB phenotypes were isolated from healthy sows, mostly encoded by the ermB and/or the mefA genes. Significantly lower frequency of mrp+/epf+/sly+ was observed among serotype 2 from healthy sows compared to those from diseased pigs. Furthermore, isolates from diseased pigs showed more homogeneously genetic patterns, with most of them clustered in pulsotypes A and E. The data indicate the genetic complexity of S. suis 2 between herds and a close linkage among isolates from healthy sows and diseased pigs. Moreover, many factors, such as extensive use of tetracycline or diffusion of Tn916 with tetM, might have favored for the pathogenicity and widespread dissemination of S. suis serotype 2.
Highlights
Streptococcus suis is an important swine pathogen leading to big loss in pig production worldwide [1]
The lowest resistance of S. suis serotype 2 for β-lactams was in accordance with other discoveries [7, 8], supporting their use as the primary drugs to treat the infection of swine S. suis serotype 2
Tetracycline-resistance has been considered to be an important cofactor in the selection of resistance to macrolides/lincosamides [9]
Summary
Streptococcus suis is an important swine pathogen leading to big loss in pig production worldwide [1]. Epidemiological surveillance has confirmed that S. suis type 2 can transmit from carrier pigs to humans [3, 4]. Healthy carrier sows, harboring S. suis type 2, are considered as the major source of infection for their offspring [5]. Since the infection of S. suis type 2 commonly occurred among suckling and weaned piglets, it is essential to investigate the association of antimicrobial resistance profile and genotypic characteristicsof isolates from carrier sows and diseased pigs. Coresistance to tetracyclines and macrolides/lincosamides in human S. suis isolates was observed, and the relevance of Tn916-like conjugative transposon in coresistant mechanisms and clone diffusion have
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
