Effects of Environmental and Management-Associated Factors on Prevalence and Diversity of Streptococcus suis in Clinically Healthy Pig Herds in China and the United Kingdom

Abstract

, a global zoonosis of pigs, shows regional differences in the prevalence of human-associated disease for Asian and non-Asian countries. The isolation rates and diversities of on tonsils of healthy slaughter pigs in China and the United Kingdom were studied for effects of geography, temperature, pig age, and farm type. Isolates underwent analysis of molecular serotype and multilocus sequence type and virulence-associated genotyping. Although we found no significant difference in positive isolation rates between Chinese and UK farms, the prevalences of serotypes previously associated with human disease were significantly greater in the Chinese collection ( = 0.003). A significant effect of temperature was found on the positive isolation rate of the Chinese samples and the prevalence of human disease-associated serotypes in the UK population (China, = 0.004; United Kingdom, = 0.024) and on the prevalence of isolates carrying key virulence genes in China ( = 0.044). Finally, we found marked diversity among isolates, with statistically significant temperature effects on detection of multiple strain types within individual pigs. This study highlighted the high carriage prevalence and diversity of among clinically healthy pig herds of China and the United Kingdom. The significant effect of temperature on prevalence of isolation, human disease-associated serotypes, and diversity carried by individual pigs may shed new light on geographic variations in human -associated disease. is a global zoonotic pathogen and also a normal colonizer mainly carried on the tonsil of pigs. Thus, it is important to study the effect of environmental and management-associated factors on the populations in clinically healthy pigs. In this research, we investigated the similarities and differences between the populations obtained from different pig ages, seasons, and farm management systems and discovered the relationship between high climatic temperature and the prevalence of .

Molecular typing of Streptococcus suis strains isolated from diseased and healthy pigs between 1996-2016

“…While serotype-1/serotype-14, serotype-2/serotype-1/2, serotype 3 to 5 and serotype 7 to 9 predominated especially among invasive isolates, as well as among lung isolates, in carrier isolates a broad range of different serotypes was identified with serotype 29 being especially prominent in collection B. A recent study on a collection of 127 carrier isolates from the UK and 223 isolates from China described serotype 16 as the most frequent type while serotype 29 was only found once in the UK and 12 times in the Chinese collection [41].…”

Identification of six novel capsular polysaccharide loci ( NCL ) from Streptococcus suis multidrug resistant non‐typeable strains and the pathogenic characteristic of strains carrying new NCL s

“…Streptococcus suis is a major swine pathogen responsible for severe economic loss to the swine industry (Gottschalk, Xu, Calzas, & Segura, ; Goyette‐Desjardins, Auger, Xu, Segura, & Gottschalk, ). Although S. suis is a normal colonizer of the upper respiratory tract of healthy pigs, it can also cause respiratory tract infections as well as serious invasive diseases such as meningitis, septicaemia, endocarditis and sudden death (Staats, Feder, Okwumabua, & Chengappa, ; Zou et al., ). In addition, S. suis has been increasingly recognized as an emerging zoonotic agent by close contact with contaminated pigs or pork.…”

Genome reduction is associated with bacterial pathogenicity across different scales of temporal and ecological divergence

“…Sequence data from all isolates was used to generate de novo assemblies using Spades v.3.10.1 (35), after first removing low quality reads using Sickle v1.33 (36). Measures were taken to ensure all assemblies were high-quality, as described in previous studies (5,(31)(32)(33).…”