ABSTRACT
INTRODUCTION: Among beta-hemolytic streptococci, Streptococcus pyogenes causes a wide variety of human disease including pharyngitis, necrotizing fasciitis and streptococcal toxic syndrome. Group A Streptococcus (GAS) uses a variety of virulence traits to colonize and then cause damage to the host; others species of beta-hemolytic streptococci are considered as emerging pathogens for humans. Despite its recognized virulence, only few studies have investigated virulence factors of GAS strains isolated in Mexico. METHODOLOGY: We conducted an epidemiological study to investigate the prevalence of GAS strains in child illnesses in Chiapas Mexico. Virulence genes encoding proteases, DNases, superantigens, as well as susceptibility to antibiotics were investigated. RESULTS: During 2010, 2013 and 2014, beta-hemolytic streptococci (N=12) were isolated from cases of bacterial infections including pharyngitis and bacteremia, with a prevalence of 0.42, 0.04 and 0.20%, respectively. S. pyogenes was the most frequent species (33%) followed by S. agalactiae and S. dysgalactiae subsp. equisimilis (25%, each). Most GAS strains encoded genes for proteases: scpA, speB, spyCEP and mac (75%), followed by sdaD and sdaB (DNases) (50%), speA and speG (superantigens; 50 and 25%, respectively). The scpA gene was amplified in all S. agalactiae strains and in ~35% of SDSE strains. Strains were all susceptible to beta-lactams, cephalosporins and quinolones. CONCLUSIONS: The present study provides evidence on the epidemiology of beta-hemolytic streptococci infecting children at the southeast Mexico, their virulence traits and sensitivity to first-line antibiotics.
ABSTRACT
Los ceparios o colecciones de microorganismos son fuentes de recursos genéticos cuyo propósito es la preservación de la diversidad biológica, garantizando su disponibilidad para actividades de docencia, investigación y comerciales. En este trabajo se verificó la viabilidad, pureza y características biológicas de las bacterias que conforman el cepario del Instituto de Ciencias Biológicas de la Universidad de Ciencias y Artes de Chiapas, y se organizó y estructuró la información obtenida en un portal virtual, para propiciar la cooperación académica. El cepario cuenta con 33 microorganismos, la mayoría del género Streptococcus y Escherichia (45,1 y 21,2%, respectivamente). Del primer género, se confirmó la identificación de S. pyogenes (40%), exhibiendo la mayoría genes que codifican para DNAsas. Con respecto al segundo género, un 58,3% de las bacterias fueron confirmadas taxonómicamente como E. coli. De esta especie, la colección cuenta con las cepas prototipo causantes de diarrea y que han preservado sus rasgos genéticos por más de cinco años. Dicho acervo ha impulsado actividades de docencia e investigación, a nivel local e internacional. Es importante que los ceparios sean fuentes sustentables de recursos biológicos, para la adquisición y suministro de especies bacterianas, con la finalidad de fomentar la interacción con la comunidad académica.
Strain collections or bacterial culture collections are genetic resources whose purpose is the preservation of biological diversity, ensuring their availability for teaching, research and trade activities. In this work viability, purity and biological characteristics of bacteria from the bacterial collection of the Institute of Biological Sciences, University of Science and Arts of Chiapas were studied. Information was structured and organized in a virtual site, to promote academic cooperation. The strain bank includes 33 microorganisms, most of the genus Streptococcus and Escherichia (45.1 and 21.2%, respectively). For Streptococcus, the identification of S. pyogenes (40%) was confirmed, by determination of most DNAses encoding genes. For Escherichia 58.3% were taxonomically confirmed as E. coli. For this species, the collection includes typical strains that produce diarrhea and their genetic traits have been preserved for more than five years. This bacterial culture collection has stimulated teaching and research activities at local and international levels. Strain collections are important sources of biological material which can provide bacterial species, in order to encourage interaction with the academic community.
