Limits...
Human Streptococcus agalactiae strains in aquatic mammals and fish.

Delannoy CM, Crumlish M, Fontaine MC, Pollock J, Foster G, Dagleish MP, Turnbull JF, Zadoks RN - BMC Microbiol. (2013)

Bottom Line: ST23 serotype Ia, a subpopulation that is normally associated with human carriage, was found in all grey seals, suggesting that human effluent may contribute to microbial pollution of surface water and exposure of sea mammals to human pathogens.The final subpopulation consisted of non-haemolytic ST260 and ST261 serotype Ib isolates, which belong to a fish-associated clonal complex that has never been reported from humans.Furthermore, it provides a rational framework for exploration of pathogenesis and host-associated genome content of S. agalactiae strains.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, UK.

ABSTRACT

Background: In humans, Streptococcus agalactiae or group B streptococcus (GBS) is a frequent coloniser of the rectovaginal tract, a major cause of neonatal infectious disease and an emerging cause of disease in non-pregnant adults. In addition, Streptococcus agalactiae causes invasive disease in fish, compromising food security and posing a zoonotic hazard. We studied the molecular epidemiology of S. agalactiae in fish and other aquatic species to assess potential for pathogen transmission between aquatic species and humans.

Methods: Isolates from fish (n = 26), seals (n = 6), a dolphin and a frog were characterized by pulsed-field gel electrophoresis, multilocus sequence typing and standardized 3-set genotyping, i.e. molecular serotyping and profiling of surface protein genes and mobile genetic elements.

Results: Four subpopulations of S. agalactiae were identified among aquatic isolates. Sequence type (ST) 283 serotype III-4 and its novel single locus variant ST491 were detected in fish from Southeast Asia and shared a 3-set genotype identical to that of an emerging ST283 clone associated with invasive disease of adult humans in Asia. The human pathogenic strain ST7 serotype Ia was also detected in fish from Asia. ST23 serotype Ia, a subpopulation that is normally associated with human carriage, was found in all grey seals, suggesting that human effluent may contribute to microbial pollution of surface water and exposure of sea mammals to human pathogens. The final subpopulation consisted of non-haemolytic ST260 and ST261 serotype Ib isolates, which belong to a fish-associated clonal complex that has never been reported from humans.

Conclusions: The apparent association of the four subpopulations of S. agalactiae with specific groups of host species suggests that some strains of aquatic S. agalactiae may present a zoonotic or anthroponotic hazard. Furthermore, it provides a rational framework for exploration of pathogenesis and host-associated genome content of S. agalactiae strains.

Show MeSH

Related in: MedlinePlus

Overview of Streptococcus agalactiae origin, isolate number (n) and results of phenotypic and genotypic characterization. Results include analysis of haemolysis (Haem), multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), molecular serotyping (MS), and profiling of surface protein genes and mobile genetic elements. Trees for MLST and PFGE results were constructed using unweighted pair group method analysis (UPGMA). Boxes enclose major clonal complexes (CCs) or sequence types (STs). STs shown in bold were first identified in the current study. ND: not determined.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3585737&req=5

Figure 1: Overview of Streptococcus agalactiae origin, isolate number (n) and results of phenotypic and genotypic characterization. Results include analysis of haemolysis (Haem), multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), molecular serotyping (MS), and profiling of surface protein genes and mobile genetic elements. Trees for MLST and PFGE results were constructed using unweighted pair group method analysis (UPGMA). Boxes enclose major clonal complexes (CCs) or sequence types (STs). STs shown in bold were first identified in the current study. ND: not determined.

Mentions: A collection of 34 S. agalactiae isolates recovered from aquatic hosts was assembled, including isolates from poikilothermic and homeothermic host species originating from multiple countries and continents (Figure 1). Of 34 isolates, 13 represented 3 separate disease outbreaks (5 isolates from an outbreak Kuwait, 4 from Honduras and 4 from Colombia) with the remaining 21 isolates each representing a single, unrelated outbreak or death. Thus, isolates in this study represented 24 epidemiologically independent events. Most fish isolates (n=18) originated from infections in farmed tilapia (Oreochromis sp.) from Honduras, Colombia, Costa Rica, Belgium, Thailand and Vietnam. The remaining fish isolates originated from infections in wild Klunzinger’s mullets (n=5; Liza klunzinger) that were part of an outbreak of streptococcosis in Kuwait or from ornamental fish from Australia, namely a rosy barb (Puntius conchonius), a golden ram (Mikrogeophagus ramirezi) and an undetermined fish species. Sea mammal isolates (n=7) were recovered at post-mortem from lung swabs of 1 bottlenose dolphin (Tursiops truncatus) and 6 grey seals (Halichoerus grypus) that had stranded at various sites around the coast of Scotland. Finally, one amphibian isolate originating from an infected farmed bullfrog (Rana rugurosa) in Thailand was available for molecular characterisation.


Human Streptococcus agalactiae strains in aquatic mammals and fish.

Delannoy CM, Crumlish M, Fontaine MC, Pollock J, Foster G, Dagleish MP, Turnbull JF, Zadoks RN - BMC Microbiol. (2013)

Overview of Streptococcus agalactiae origin, isolate number (n) and results of phenotypic and genotypic characterization. Results include analysis of haemolysis (Haem), multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), molecular serotyping (MS), and profiling of surface protein genes and mobile genetic elements. Trees for MLST and PFGE results were constructed using unweighted pair group method analysis (UPGMA). Boxes enclose major clonal complexes (CCs) or sequence types (STs). STs shown in bold were first identified in the current study. ND: not determined.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3585737&req=5

Figure 1: Overview of Streptococcus agalactiae origin, isolate number (n) and results of phenotypic and genotypic characterization. Results include analysis of haemolysis (Haem), multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), molecular serotyping (MS), and profiling of surface protein genes and mobile genetic elements. Trees for MLST and PFGE results were constructed using unweighted pair group method analysis (UPGMA). Boxes enclose major clonal complexes (CCs) or sequence types (STs). STs shown in bold were first identified in the current study. ND: not determined.
Mentions: A collection of 34 S. agalactiae isolates recovered from aquatic hosts was assembled, including isolates from poikilothermic and homeothermic host species originating from multiple countries and continents (Figure 1). Of 34 isolates, 13 represented 3 separate disease outbreaks (5 isolates from an outbreak Kuwait, 4 from Honduras and 4 from Colombia) with the remaining 21 isolates each representing a single, unrelated outbreak or death. Thus, isolates in this study represented 24 epidemiologically independent events. Most fish isolates (n=18) originated from infections in farmed tilapia (Oreochromis sp.) from Honduras, Colombia, Costa Rica, Belgium, Thailand and Vietnam. The remaining fish isolates originated from infections in wild Klunzinger’s mullets (n=5; Liza klunzinger) that were part of an outbreak of streptococcosis in Kuwait or from ornamental fish from Australia, namely a rosy barb (Puntius conchonius), a golden ram (Mikrogeophagus ramirezi) and an undetermined fish species. Sea mammal isolates (n=7) were recovered at post-mortem from lung swabs of 1 bottlenose dolphin (Tursiops truncatus) and 6 grey seals (Halichoerus grypus) that had stranded at various sites around the coast of Scotland. Finally, one amphibian isolate originating from an infected farmed bullfrog (Rana rugurosa) in Thailand was available for molecular characterisation.

Bottom Line: ST23 serotype Ia, a subpopulation that is normally associated with human carriage, was found in all grey seals, suggesting that human effluent may contribute to microbial pollution of surface water and exposure of sea mammals to human pathogens.The final subpopulation consisted of non-haemolytic ST260 and ST261 serotype Ib isolates, which belong to a fish-associated clonal complex that has never been reported from humans.Furthermore, it provides a rational framework for exploration of pathogenesis and host-associated genome content of S. agalactiae strains.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, UK.

ABSTRACT

Background: In humans, Streptococcus agalactiae or group B streptococcus (GBS) is a frequent coloniser of the rectovaginal tract, a major cause of neonatal infectious disease and an emerging cause of disease in non-pregnant adults. In addition, Streptococcus agalactiae causes invasive disease in fish, compromising food security and posing a zoonotic hazard. We studied the molecular epidemiology of S. agalactiae in fish and other aquatic species to assess potential for pathogen transmission between aquatic species and humans.

Methods: Isolates from fish (n = 26), seals (n = 6), a dolphin and a frog were characterized by pulsed-field gel electrophoresis, multilocus sequence typing and standardized 3-set genotyping, i.e. molecular serotyping and profiling of surface protein genes and mobile genetic elements.

Results: Four subpopulations of S. agalactiae were identified among aquatic isolates. Sequence type (ST) 283 serotype III-4 and its novel single locus variant ST491 were detected in fish from Southeast Asia and shared a 3-set genotype identical to that of an emerging ST283 clone associated with invasive disease of adult humans in Asia. The human pathogenic strain ST7 serotype Ia was also detected in fish from Asia. ST23 serotype Ia, a subpopulation that is normally associated with human carriage, was found in all grey seals, suggesting that human effluent may contribute to microbial pollution of surface water and exposure of sea mammals to human pathogens. The final subpopulation consisted of non-haemolytic ST260 and ST261 serotype Ib isolates, which belong to a fish-associated clonal complex that has never been reported from humans.

Conclusions: The apparent association of the four subpopulations of S. agalactiae with specific groups of host species suggests that some strains of aquatic S. agalactiae may present a zoonotic or anthroponotic hazard. Furthermore, it provides a rational framework for exploration of pathogenesis and host-associated genome content of S. agalactiae strains.

Show MeSH
Related in: MedlinePlus