Genomic analysis of virulence factors and antimicrobial resistance of group B Streptococcus isolated from pregnant women in northeastern Mexico.

INTRODUCTION: Group B Streptococcus (GBS) causes infections in women during pregnancy and puerperium and invasive infections in newborns. The genes lmb, cylE, scpB, and hvgA are involved with increased virulence of GBS, and hypervirulent clones have been identified in different regions. In addition, increasing resistance of GBS to macrolides and lincosamides has been reported, so knowing the patterns of antibiotic resistance may be necessary to prevent and treat GBS infections. This study aimed to identify virulence genes and antibiotic resistance associated with GBS colonization in pregnant women from northeastern Mexico. METHODS: Pregnant women with 35-37 weeks of gestation underwent recto-vaginal swabbing. One swab was inoculated into Todd-Hewitt broth supplemented with gentamicin and nalidixic acid, a second swab was inoculated into LIM enrichment broth, and a third swab was submerged into a transport medium. All samples were subcultured onto blood agar. After overnight incubation, suggestive colonies with or without hemolysis were analyzed to confirm GBS identification by Gram staining, catalase test, hippurate hydrolysis, CAMP test, and incubation in a chromogenic medium. We used latex agglutination to confirm and serotype GBS isolates. Antibiotic resistance patterns were assessed by Vitek 2 and disk diffusion. Periumbilical, rectal and nasopharyngeal swabs were collected from some newborns of colonized mothers. All colonized women and their newborns were followed up for three months to assess the development of disease attributable to GBS. Draft genomes of all GBS isolates were obtained by whole-genome sequencing. In addition, bioinformatic analysis to identify genes encoding capsular polysaccharides and virulence factors was performed using BRIG, while antibiotic resistance genes were identified using the CARD database. RESULTS: We found 17 GBS colonized women out of 1154 pregnant women (1.47%). None of the six newborns sampled were colonized, and no complications due to GBS were detected in pregnant women or newborns. Three isolates were serotype I, 5 serotype II, 3 serotype III, 4 serotype IV, and 2 serotype V. Ten distinct virulence gene profiles were identified, being scpB, lmb, fbsA, acp, PI-1, PI-2a, cylE the most common (3/14, 21%). The virulence genes identified were scpB, lmb, cylE, PI-1, fbsA, PI-2a, acp, fbsB, PI-2b, and hvgA. We identified resistance to tetracycline in 65% (11/17) of the isolates, intermediate susceptibility to clindamycin in 41% (7/17), and reduced susceptibility to ampicillin in 23.5% (4/17). The tetM gene associated to tetracyclines resistance was found in 79% (11/14) and the mel and mefA genes associated to macrolides resistance in 7% (1/14). CONCLUSIONS: The low prevalence of colonization and the non-occurrence of mother-to-child transmission suggest that the intentional search for GBS colonization in this population is not justified. Our results also suggest that risk factors should guide the use of intrapartum antibiotic prophylaxis. The detection of strains with genes coding virulence factors means that clones with pathogenic potential circulates in this region. On the other hand, the identification of decreased susceptibility to antibiotics from different antimicrobial categories shows the importance of adequately knowing the resistance patterns to prevent and to treat GBS perinatal infection.

Association of the Vascular Endothelial Growth Factor Gene Polymorphism +936 C/T with Diabetic Neuropathy in Patients with Type 2 Diabetes Mellitus.

BACKGROUND: Peripheral neuropathy is one of the most common late complications of diabetes. Vascular endothelial growth factor (VEGF) gene polymorphisms have been associated with the development of peripheral neuropathy in different populations of patients with type 2 diabetes mellitus (DM2). OBJECTIVE: To analyze the prevalence of the +936 C/T VEGF gene polymorphism among patients with DM2 with and without peripheral neuropathy. STUDY DESIGN AND METHODOLOGY: 218 unrelated DM2 patients, 90 with and 128 without peripheral neuropathy were genotyped for the +936 C/T VEGF gene polymorphism using PCR amplification followed by restriction length polymorphism analysis. RESULTS: The CC homozygous VEGF+936 C/T (rs3025039) was the predominant genotype in DM2 patients with peripheral neuropathy, whereas the predominant genotype in patients without neuropathy was the heterozygous C/T. No statistical association was found between genotype distribution and the presence of neuropathy (p = 0.063). The distribution of the genotypes according to the dominant (CC vs. CT + TT) and recessive (TT vs. CT + CC) models showed that the homozygous CC and TT genotypes, respectively, are not risk factors for neuropathy. The CT genotype conferred a protective effect as seen in the over-dominant model (CT vs. CC + TT) (OR = 0.52; 95% CI = 0.300-0.90; p = 0.019). CONCLUSION: We conclude that the VEGF+936 C/T (rs3025039) gene polymorphisms are related to peripheral neuropathy in Mexican DM2 patients, with the heterozygous genotype potentially conferring a protective effect.