Population structure and virulence gene profiles of Streptococcus agalactiae collected from different hosts worldwide

Abstract

Streptococcus agalactiae is a leading cause of morbidity and mortality among neonates and causes severe infections in pregnant women and nonpregnant predisposed adults, in addition to various animal species worldwide. Still, information on the population structure of S. agalactiae and the geographical distribution of different clones is limited. Further data are urgently needed to identify particularly successful clones and obtain insights into possible routes of transmission within one host species and across species borders. We aimed to determine the population structure and virulence gene profiles of S. agalactiae strains from a diverse set of sources and geographical origins. To this end, 373 S. agalactiae isolates obtained from humans and animals from five different continents were typed by DNA microarray profiling. A total of 242 different S. agalactiae strains were identified and further analyzed. Particularly successful clonal lineages, hybridization patterns, and strains were identified that were spread across different continents and/or were present in more than one host species. In particular, several strains were detected in both humans and cattle, and several canine strains were also detected in samples from human, bovine, and porcine hosts. The findings of our study suggest that although S. agalactiae is well adapted to various hosts including humans, cattle, dogs, rodents, and fish, interspecies transmission is possible and occurs between humans and cows, dogs, and rabbits. The virulence and resistance gene profiles presented enable new insights into interspecies transmission and make a crucial contribution to the identification of suitable targets for therapeutic agents and vaccines.

Genomic analysis of group B Streptococcus from milk demonstrates the need for improved biosecurity: a cross-sectional study of pastoralist camels in Kenya

“…Assembled genomes were scanned for the presence of human-associated virulence genes scpB and lmb [44] using tBLASTn. Capsular serotyping was conducted in silico using a standard method [45].…”

Multidrug Resistance and Molecular Characterization of Streptococcus agalactiae Isolates From Dairy Cattle With Mastitis

“…Also, S. agalactiae infections have been reported in many fish species, particularly is an emerging pathogen in Nile tilapia (Oreochromis niloticus) worldwide (Mian et al, 2009). Recent studies debate if this zoonotic potential remains nowadays and suggest that although S. agalactiae is well adapted to various hosts, interspecies transmission is possible and occurs (Morach et al, 2018). Further, they hypothesize about possible routes through which this bacterium could be transmitted between cattle and humans (Botelho et al, 2018).…”

Galleria mellonella as an infection model for the multi-host pathogen Streptococcus agalactiae reflects hypervirulence of strains associated with human invasive disease

“…Despite some level of host adaptation, e.g. association of ST17 with human neonatal infectious disease [10], ST67 with cattle [18] and association of ST7, ST283 and clonal complex (CC) 552 with poikilothermic animals [19], host-association is not absolute and interspecies transmission between people, cattle and fish may occur [16,20,21].…”