Veterynarna biotehnologija – Veterinary biotechnology, 2021, 39, 117-127 [in Ukrainian]. https://doi.org/10.31073/vet_biotech39-11
1Institute of Veterinary Medicine NAAS
2Bila Tserkva National Agrarian University
DISSEMINATION OF STREPTOCOCCUS SUIS SEROTYPES IN UKRAINE
Introduction. Streptococcus suis is widely disseminated pathogen of pig industry in the world. Today are known more than 35 different capsular serotypes of S. suis. In the last years it was registered the significant growth of streptococcal infections prevalence. Considering these, the issue of prevention and treatment of streptococcosis is important for pig industry sustainability.
The goal of the work was to detect of the predominant serotypes of Streptococcus suis strains isolated in Ukraine using PCR test.
Materials and methods. It was used 32 isolates and reference strain NCTC 10234 of Streptococcus suis from museum of the Institute of veterinary medicine NAAS. Studies of morphological and cultural properties were performed using conventional bacteriological methods.
The serotype of isolates was determined by multiplex PCR test (classical conventional method with electrophoretic reading of results) using three sets of primers recommended by Kerdsin et al. (2012), as well as an additional pair of primers to determine the species. The assay parameters were optimized by us.
The results of experimental studies are processed by conventional methods of statistics.
Results of research and discussion. Isolates from different regions of Ukraine were confirmed as S. suis by cultural, morphological, enzymatic and biological properties. In our study, the multiplex PCR used by us revealed 8 serotypes of S. suis. At the same time, the type of microorganism was identified. Streptococcus suis predominantly was isolated from the synovial fluid of the joints affected by arthritis – serotypes 1, 2, 1/2, 14, 5, 7 and from blood – serotypes 1, 2, ½, 7, 14 were detected. Serotypes 2, 7 and 10 were isolated from the lungs, and from brain and spleen – serotypes 2 and ½. Thus, the predominant serotypes that caused severe lesions in pigs were 1, 2, 1/2, 5, 7, 10, 14.
The largest number of isolates of the causative agent of swine streptococcus occurs in the age groups of suckling piglets (28.2%) and weaners (53.1%), i.e. from birth to 4 months. Circulation of serotypes 2, ½. 1, 14, 5, 7 was detected in these age groups. Serotypes 2 and 1/2 were detected in samples from newborn piglets, and serotypes 1, 14 and 7, which are less pathogenic and act as opportunistic, were isolated from biomaterial of fattening pigs in which a subclinical form of streptococcus was registered in most cases.
Conclusions and prospects for further research:
1. As a result of the conducted researches it was established that the method of multiplex PCR allows to detect serotypes of Streptococcus suis which are prevalent in population of pigs in Ukraine.
2. Analysis of the results of streptococcal seroprevalence in pigs of different age groups showed the majority of detected cases are suckling piglets (28.2%) and weaning group (53.1%), among which circulate mainly highly virulent serotypes 2, 1/2, 1,14, 5, 7. Circulation of serotypes 7 and 10 is typical for adult animals and group of fattening pigs.
The using of PCR for S.suis serotyping in Ukraine is important to determining the predominant serotypes in order to select the optimal composition of the vaccine for the specific prevention of swine streptococcosis
Keywords: Streptococcus suis, serotype, PCR, isolate, pathogenicity.