Transfer of antibiotic resistance determinants between lactobacilli isolates from the gastrointestinal tract of chicken.

The aim of this study was to assess the potential horizontal transfer of genetic traits for antibiotic resistance between lactobacilli isolated from the chicken gut, both in vitro and in vivo. Thirty-seven Lactobacillus spp. strains isolated from the gizzard, small and large intestines and caeca of free-range broiler chickens showed multi-drug resistance as assessed by disc diffusion assays. The minimum inhibitory concentration (MIC) for vancomycin, tetracycline, erythromycin and chloramphenicol was determined in De Man, Rogosa and Sharpe broth in a microplate assay. Almost all the lactobacilli isolates were resistant to vancomycin (except strains belonging to the Lactobacillus acidophilus group) and to tetracycline (MIC≥128 µg/ml). Only five strains were resistant to erythromycin, and six to chloramphenicol. The transfer rate in filter mating experiments performed using L. acidophilus strain 4M14E (EmR), Lactobacillus vaginalis strain 5M14E (CmR), Lactobacillus salivarius strain 5C14C (EmR), and the 4G14L and 3C14C strains of Lactobacillus reuteri (CmR) showed a frequency of approximately 1×104 cfu/ml of double-resistant transconjugants for the different combinations. The exception was the L. salivarius 5C14C (EmR) and L. vaginalis 5M14E (CmR) mating combination, which produced no transconjugants. In vivo experiments performed in gnotobiotic mice by mating L. acidophilus 4M14E (EmR) with L. reuteri 3C14C (CmR), L. reuteri 4G14L (CmR) or L. vaginalis 5M14E (CmR) resulted in transconjugants at 3.95±0.29, 3.16±0.33, and 4.55±1.52 log10 cfu/g of faeces, respectively. Taken together, these data suggest that genetic exchange may occur between native bacterial strains within the gastrointestinal tract of chickens, which might maintain a dynamic gene pool conferring antibiotic resistance upon indigenous microbiota components, even in the absence of the pathogens. This possibility must be taken into account as a complementary criterion when lactobacilli are screened for probiotic use.

Estimated Prevalence of Viral Hepatitis in the General Population of the Municipality of São Paulo, Measured by a Serologic Survey of a Stratified, Randomized and Residence-Based Population.

The present study was done to estimate the prevalence of Hepatitis A (HAV), B (HBV), C (HCV), and E (HEV) infection in the general population residing in the municipality of São Paulo, and to evaluate the level of knowledge related to the various modes of infection transmission by and protection against the different viruses. Blood samples and health questionnaires were collected from 1,059 individuals. The study design used an inductive method of predictive statistical inferences through randomized sampling stratified by Sex, age and residence region. The estimated prevalence rated found were: Hepatitis A = 66.59% (63.75%-69.44% CI); Hepatitis B = 5.94% (4.50%-7.35%); Hepatitis C = 1.42% (0,70%-2.12%); Hepatitis E = 1.68% (0.91%-2.46%). The frequency of hepatitis was similar in males and females. HAV showed an estimated prevalence of 56.16% in the population up to 17 years old, increasing to 65.30% in individuals between 18 and 29 years. The infection reached its peak of 90% in individuals 40 years of age or older. The study showed a greater tendency of dissemination of HBV among the population between 15 and 17 years. This specific age group showed an estimated prevalence of active infection of 1.04% (0.43%-1.65% CI), and also demonstrated an ascending level of acquired immunity with an estimated prevalence of 4.90% (3.60%-6.20% CI). HCV demonstrated an estimated prevalence of 1.42% (0.70%-2.12% CI). This specific infection occurred more frequently among adults 30 years of age or older, with the prevalence reaching a peak of 3.80% among the group aged 50 to 59 years. HEV showed zero prevalence among the age group between 2 and 9 years. This was followed by a slightly ascending rate starting from age 10, with an estimated prevalence of 1.05% (0.94%-3.04% CI) among those 10 to 14 years of age. This infection reached its peak of 3.00% (0.55%-6.74% CI) at the age of 60 years or older. Individuals with lower educational levels had a higher tendency of acquiring HAV and HCV, while there was no statistically significant difference for this parameter related to HBV and HEV. HBV occurred more frequently among inhabitants of the northern region of the city. All other hepatitis forms occurred at similar frequencies among the five regions of the city. Among the population, 1.90% (1.08%-2.72% CI) demonstrated an elevated hepatic enzyme with no serologic evidence indicating the cause was the viruses studied. This observation suggests the presence of other hepatic diseases, possibly including other viral diseases. It was also estimated that 75.12% of the city's population did not know the modes of transmission of hepatitis viruses and 76.70% did not know how to prevent them. This clearly suggests the need for a full-scale education program combined with public health measures regarding prevention of all forms of vial hepatitis.