RESUMEN
As the human population grows, an increase in food trade is needed. This elevates the risk of epidemiological outbreaks. One of the prevalent pathogens associated with food production in Mexico has been Salmonella Oranienburg. Effective surveillance systems require microbial genetic knowledge. The objective of this work is to describe the genetic composition of Mexican S. Oranienburg genomes. For that, 53 strains from different environmental sources were isolated and sequenced. Additionally, 109 S. Oranienburg genomes were downloaded. Bioinformatic analyses were used to explore the clonal complex and genomic relatedness. A major clonal group formed by ST23 was identified comprising four STs. 202 SNPs were found the maximum difference among isolates. Virulence genes for host invasion and colonization as rpoS, fimbria type 1, and, T3SS were found common for all isolates. This study suggests that Mexican S. Oranienburg strains are potential pathogens circulating continuously in the region between host and non-host environments.
Asunto(s)
Genómica , Humanos , MéxicoRESUMEN
The implementation of good agricultural practices (GAP) from irrigation water to the tomato packaging process enhances the safety of fresh produce and its value throughout the food chain. The aim of the present study was to show that fresh produce farms that apply and enforce GAP could reduce the presence of Salmonella in finished produce. Samples were collected biweekly from six packing houses from the central region of Sinaloa, México, for the isolation of Salmonella spp by the ISO 6579:2002 method, and the isolated strains were serotyped and genotyped by the Kauffmman-White scheme and pulsed field gel electrophoresis (PFGE), respectively. Salmonella strains were detected in 13 (36.1 %) irrigation water samples, while only two tomato samples were positive (5.5 %). Eight different serotypes were identified in irrigation water, and Salmonella Oranienburg (34 %) was the most prevalent; however, only Salmonella Agona and Salmonella Weltevreden were present on tomatoes. Salmonella Oranienburg was the most widely dispersed and variable serotype, with 10 different PFGE profiles. Salmonella Weltevreden was isolated from both types of samples, albeit with distinct genetic profiles, implying that the sources of contamination differ. These results confirm the utility of implementing good agricultural practices to reduce Salmonella contamination in irrigation water and the packaging process.
Asunto(s)
Agricultura/métodos , Solanum lycopersicum/crecimiento & desarrollo , Calidad del Agua/normas , Monitoreo del Ambiente , Microbiología de Alimentos , Solanum lycopersicum/microbiología , México , Salmonella/aislamiento & purificación , Microbiología del Suelo , Eliminación de Residuos LíquidosRESUMEN
AIMS: This study aimed to determine if the children's leisure activities impact the presence of pathogens on their hands and toys. METHODS & RESULTS: To assess the microbiological hazard in playground areas, a pilot study that included 12 children was conducted. We then conducted an intervention study; children's hands and toys were washed before playing. Faecal coliforms, pathogenic bacteria and Giardia lamblia were quantified by membrane filtration, selective media and flotation techniques, respectively; rotavirus, hepatitis A and rhinovirus by RT-PCR. Pilot study results revealed faecal contamination on children's hands and toys after playing on sidewalks and in public parks. Pathogenic bacteria, hepatitis A and G. lamblia on children's hands were also found. In the intervention study, Staphylococcus aureus and Klebsiella pneumoniae were found on children's hands at concentrations up to 2·5 × 10(4) and 1 × 10(4) CFU hands(-1), respectively. E. coli and Kl. pneumoniae were detected on toys (2·4 × 10(3) and 2·7 × 10(4) CFU toy(-1), respectively). Salmonella spp, Serratia spp and G. lamblia cysts were also present on toys. CONCLUSION: Children's play activities influence microbial presence on hands and toys; the transfer seems to occur in both ways. SIGNIFICANCE AND IMPACT OF THE STUDY: Control strategy needs to be implemented to protect children from infectious diseases.
Asunto(s)
Bacterias/aislamiento & purificación , Microbiología Ambiental , Mano/microbiología , Mano/virología , Juego e Implementos de Juego , Virus/aislamiento & purificación , Niño , Preescolar , Heces/microbiología , Heces/parasitología , Heces/virología , Femenino , Giardia lamblia/aislamiento & purificación , Mano/parasitología , Humanos , Masculino , Proyectos PilotoRESUMEN
AIMS: To identify and quantify the presence of Escherichia coli, Staphylococcus aureus, Salmonella, hepatitis A and norovirus in households and to assess the effect of chlorine and quaternary ammonium-based disinfectants following a prescribed use. METHODS AND RESULTS: Eleven sites distributed in kitchen, bathroom, pet and children's areas of two groups of 30 homes each: (i) a nonprescribed disinfectant user group and (ii) a disinfectant protocol user group. During the 6-week study, samples were collected once a week except for week one when sample collection occurred immediately before and after disinfectant application to evaluate the disinfectant protocol. The concentration and occurrence of bacteria were less in the households with prescribed use of disinfectants. The greatest reductions were for E. coli (99%) and Staph. aureus (99·9999%), respectively. Only two samples were positive for HAV, while norovirus was absent. Disinfection protocols resulted in a significant (P < 0·05) microbial reduction in all areas of the homes tested compared to homes not using a prescribed protocol. CONCLUSIONS: The study suggests that disinfectant product application under specific protocol is necessary to achieve greater microbial reductions. SIGNIFICANCE AND IMPACT OF THE STUDY: Prescribed protocols constitute an important tool to reduce the occurrence of potential disease-causing micro-organisms in households.