Human Milk Secretory Antibodies against Attaching and Effacing Escherichia coli Antigens

Secretory immunoglobulin A (sIgA) is a primary factor responsible for preventing attachment of enteropathogens to gut epithelium in breastfeeding infants. We compared the frequency of sIgA to major surface antigens of enterohemorrhagic Escherichia coli (EHEC) in milk of 123 women from the United States and Mexico to determine whether regional differences existed in the frequency of antibodies to these surface antigens. In both groups of women, milk commonly has sIgA against various EHEC lipopolysaccharides, EspA, EspB, intimin, and less frequently against Shiga toxin. The study suggests that persons living in the U.S. are exposed to attaching/effacing enteropathogens more frequently than is generally assumed. The low frequency of antibodies to Stx1 (in 12% of Mexican and in 22% of U.S. samples) suggests that the rare appearance of hemolytic uremic syndrome in adults is not due to neutralization of toxin at the gut level. Only anti-EspA is found in most milk samples from both populations of women. EspA may represent a useful target for an immunization strategy to prevent EHEC disease in humans

Genetic diversity of drug and multidrug-resistant Mycobacterium tuberculosis circulating in Veracruz, Mexico.

BACKGROUND:Mexico is one of the most important contributors of drug and multidrug-resistant tuberculosis in Latin America; however, knowledge of the genetic diversity of drug-resistant tuberculosis isolates is limited. METHODS:In this study, the genetic structure of 112 Mycobacterium tuberculosis strains from the southeastern Mexico was determined by spoligotyping and 24-loci MIRU-VNTRs. FINDINGS:The results show eight major lineages, the most of which was T1 (24%), followed by LAM (16%) and H (15%). A total of 29 (25%) isolates were identified as orphan. The most abundant SITs were SIT53/T1 and SIT42/LAM9 with 10 isolates each and SIT50/H3 with eight isolates. Fifty-two spoligotype patterns, twenty-seven clusters and ten clonal complexes were observed, demonstrating an important genetic diversity of drug and multidrug-resistant tuberculosis isolates in circulation and transmission level of these aggravated forms of tuberculosis. Being defined as orphan or as part of an orphan cluster, was a risk factor for multidrug resistant-tuberculosis (OR 2.5, IC 1.05-5.86 and OR 3.3, IC 1-11.03, respectively). Multiple correspondence analyses showed association of some clusters and SITs with specific geographical locations. CONCLUSIONS:Our study provides one of the most detailed description of the genetic structure of drug and multidrug-resistant tuberculosis strains in southeast Mexico, establishing for the first time a baseline of the genotypes observed in resistant isolates circulating, however further studies are required to better elucidate the genetic structure of tuberculosis in region and the factors that could be participating in their dispersion

Geographical distribution of the isolates recovered from Veracruz, Mexico.

<p>Geographical distribution of the isolates recovered from Veracruz, Mexico.</p