Streptococcus suis is a significant zoonotic pathogen commonly found in pigs and their environments, and it is increasingly recognized for its role in human infections and antibiotic resistance. Notably, up to 80% of antibiotic resistance genes in S. suis are plasmid-encoded, raising concerns about its contribution to the spread of resistance. This study aimed to evaluate the antibiotic resistance patterns of different S. suis strains isolated from pigs and their surrounding environments. Samples were collected from various anatomical sites of pigs and nearby areas and analyzed using standard microbiological methods for the identification of S. suis. Antibiotic susceptibility testing was conducted using the disk diffusion method. The isolates were identified as S. suis Q, R, S, and Y. Resistance rates among these strains were 24.14% (S. suis Q), 100.00% (S. suis R), 41.67% (S. suis S), and 39.23% (S. suis Y). Furthermore, 64.29% of Q, 100.00% of R, and 63.64% of S isolates exhibited multiple antibiotic resistance (MAR), with 61.76% of the resistant strains having MAR indices greater than 0.2. Among the isolates, S. suis Q was the most prevalent, particularly in nasal samples. These findings highlight the presence of diverse, multiple antibiotic-resistant S. suis strains in pig populations and their environments, underscoring the potential public health risks and the need for vigilant monitoring and control strategies.
Kenechukwu David Somtochukwu Obi (Wed,) studied this question.