Streptococcus suis Research Update: Serotype Prevalence and Antimicrobial Resistance Distribution in Swine Isolates Recovered in Spain from 2020 to 2022

Abstract

This study aimed to update the Streptococcus suis serotype distribution in Spain by analysing 302 clinical isolates recovered from diseased pigs between 2020 and 2022. The main objectives were to identify prevalent serotypes, differentiate specific serotypes 1, 14, 2, and 1/2, investigate specific genotypic and phenotypic antimicrobial resistance features, and explore associations between resistance genes and phenotypic resistances. Serotypes 9 (21.2%), 1 (16.2%), 2 (15.6%), 3 (6%), and 7 (5.6%) were the most prevalent, whereas serotypes 14 and 1/2 corresponded with 4.3% and 0.7% of all isolates. Antimicrobial resistance genes, including tet(O), erm(B), lnu(B), lsa(E), tet(M), and mef(A/E), were analysed, which were present in 85.8%, 65.2%, 7%, 7%, 6.3%, and 1% of the samples, respectively. Susceptibility testing for 18 antimicrobials revealed high resistance levels, particularly for clindamycin (88.4%), chlortetracycline (89.4%), and sulfadimethoxine (94.4%). Notably, seven significant associations (p < 0.0001) were detected, correlating specific antimicrobial resistance genes to the observed phenotypic resistance. These findings contribute to understanding the S. suis serotype distribution and its antibiotic resistance profiles in Spain, offering valuable insights for veterinary and public health efforts in managing S. suis-associated infections.

Isolation, Identification, Genomic Diversity, and Antimicrobial Resistance Analysis of Streptococcus suis in Hubei Province of China from 2021 to 2023

“…Streptococcus pneumoniae ATCC 49619 served as the positive control. The resistance/susceptibility to each antibiotic was determined based on breakpoints established in CLSI (VET08-ED4 and M100-ED29) [22,23], and when not available, the literature was used [24][25][26].…”