RESUMO
In the last 10 years, Salmonella Heidelberg has been extensively isolated from poultry in several countries. In this context, molecular characterization is essential to understand whether the strains have entered the farms from a single or several sources. Thus, the aim of this study was to determine the genetic relationship and antimicrobial susceptibility of S. Heidelberg strains isolated between 2011 and 2012 from broiler farms belonging to three integrated poultry companies located in Argentina. The genetic relatedness of the S. Heidelberg isolates was determined by pulsed-field gel electrophoresis (PFGE), and resistance to 21 antimicrobials was determined by the disc diffusion method. The isolates were assigned to four PFGE patterns. Most of the strains showed 100% similarity and belonged to the same integrated poultry company. This PFGE pattern was also prevalent in S. Heidelberg strains isolated from humans in several provinces of Argentina, which suggests an epidemiological association between human and poultry strains. All the isolates were classified as multidrug-resistant (MDR), and no clear relationship was observed between PFGE and resistance patterns. S. Heidelberg strains may circulate among farms from the same integrated company due to common sources of contamination. To guarantee the safety of the poultry product for the consumers, holistic approaches including surveillance of Salmonella throughout the production chain together with control measures are crucial.
Assuntos
Antibacterianos/farmacologia , Galinhas/microbiologia , Farmacorresistência Bacteriana , Doenças das Aves Domésticas/microbiologia , Salmonelose Animal/microbiologia , Salmonella/classificação , Animais , Salmonelose Animal/epidemiologiaRESUMO
In order to control and eradicate epidemic cholera, we need to understand how epidemics begin, how they spread, and how they decline and eventually end. This requires extensive sampling of epidemic disease over time, alongside the background of endemic disease that may exist concurrently with the epidemic. The unique circumstances surrounding the Argentinian cholera epidemic of 1992-1998 presented an opportunity to do this. Here, we use 490 Argentinian V. cholerae genome sequences to characterise the variation within, and between, epidemic and endemic V. cholerae. We show that, during the 1992-1998 cholera epidemic, the invariant epidemic clone co-existed alongside highly diverse members of the Vibrio cholerae species in Argentina, and we contrast the clonality of epidemic V. cholerae with the background diversity of local endemic bacteria. Our findings refine and add nuance to our genomic definitions of epidemic and endemic cholera, and are of direct relevance to controlling current and future cholera epidemics.
Assuntos
Cólera/microbiologia , Doenças Endêmicas/prevenção & controle , Genoma Bacteriano/genética , Pandemias/prevenção & controle , Vibrio cholerae/genética , Argentina/epidemiologia , Cólera/epidemiologia , Cólera/prevenção & controle , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , História do Século XIX , História do Século XX , Humanos , Anotação de Sequência Molecular , Pandemias/história , Filogenia , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Vibrio cholerae/isolamento & purificação , Vibrio cholerae/patogenicidadeRESUMO
Shigella spp. are a leading cause of human diarrheal disease worldwide, with Shigella flexneri being the most frequently isolated species in developing countries. This serogroup is presently classified into 19 serotypes worldwide. We report here a multicenter validation of a multiplex-PCR-based strategy previously developed by Q. Sun, R. Lan, Y. Wang, A. Zhao, et al. (J Clin Microbiol 49:3766-3770, 2011) for molecular serotyping of S. flexneri This study was performed by seven international laboratories, with a panel of 71 strains (researchers were blind to their identity) as well as 279 strains collected from each laboratory's own local culture collections. This collaborative work found a high extent of agreement among laboratories, calculated through interrater reliability (IRR) measures for the PCR test that proved its robustness. Agreement with the traditional method (serology) was also observed in all laboratories for 14 serotypes studied, while specific genetic events could be responsible for the discrepancies among methodologies in the other 5 serotypes, as determined by PCR product sequencing in most of the cases. This work provided an empirical framework that allowed the use of this molecular method to serotype S. flexneri and showed several advantages over the traditional method of serological typing. These advantages included overcoming the problem of availability of suitable antisera in testing laboratories as well as facilitating the analysis of multiple samples at the same time. The method is also less time-consuming for completion and easier to implement in routine laboratories. We recommend that this PCR be adopted, as it is a reliable diagnostic and characterization methodology that can be used globally for laboratory-based shigella surveillance.
Assuntos
Reação em Cadeia da Polimerase Multiplex/métodos , Sorotipagem/métodos , Shigella flexneri/classificação , Técnicas de Tipagem Bacteriana/métodos , Técnicas de Tipagem Bacteriana/normas , DNA Bacteriano/genética , Humanos , Internacionalidade , Reação em Cadeia da Polimerase Multiplex/normas , Sorogrupo , Shigella flexneri/imunologiaAssuntos
Azitromicina/efeitos adversos , Farmacorresistência Bacteriana/genética , Genes Bacterianos , Salmonella typhimurium/efeitos dos fármacos , Azitromicina/uso terapêutico , Hospitais , Humanos , América Latina/epidemiologia , Testes de Sensibilidade Microbiana , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/microbiologia , Salmonella typhimurium/genética , Sequenciamento Completo do GenomaAssuntos
Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Serratia/microbiologia , Serratia marcescens/genética , beta-Lactamases/genética , Argentina/epidemiologia , Infecção Hospitalar/epidemiologia , Surtos de Doenças , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Humanos , Infecções por Serratia/epidemiologia , Serratia marcescens/isolamento & purificação , Serratia marcescens/patogenicidadeRESUMO
Argentina has the highest frequency of hemolytic uremic syndrome (HUS) in the world (300 cases/year). The risk of HUS in children from 6 to 48 months old is approximately 22/100,000 in Buenos Aires. In Argentina, HUS is the most frequent cause of acute renal damage and the second cause of chronic renal injury in children. We have shown that during the spring/summer season, the incidence of Shiga-like toxin (SLT)-associated bloody diarrhea in children less than 5 years old is 30 to 39%. The risk of HUS in SLT-associated bloody diarrhea is about 4 to 5%; 14% of children with SLT diarrhea developed incomplete HUS. Household contacts of children with HUS are commonly colonized with SLT-producing Escherichia coli (39%), and seroconversion occurs in 42% of these. No evidence of free fecal SLTs was observed in healthy children. In Argentina E. coli serotype O157:H7 has been associated with only 2 to 18% of HUS patients and in 4.5 to 7% of children with bloody diarrhea. Other serotypes were also recognized. About 20% of Argentine children start to eat meat at 5 months old, and 80% of them have meat in their diets at least three times a week. Eighty percent of the meat consumed is undercooked. Few data about the incidence of SLT-producing E. coli in cows in our country are available. E. coli O157:H7 was isolated in only 7.7% of calves aged 1 to 3 weeks with E. coli bacillosis from different farms in Argentina. Preliminary data show that SLT-producing E. coli were also present in stools from healthy animals and in fresh retail ground beef, determined by polymerase chain reaction.