SummaryIn the present study we investigated the potential role of Toll-like receptor 4 (TLR-4) Asp299Gly and Thr399Ile polymorphisms as risk factors in the development of gastric cancer. TLR-4 Asp299Gly and Thr399Ile polymorphisms were investigated in 171 Italian patients with sporadic gastric cancer and in 151 controls. Unconditional regression (odds ratio and 95% confidence intervals) were used to investigate the association of the studied polymorphisms with gastric cancer. TLR-4 Thr399Ile polymorphism is linked with an increased susceptibility to gastric cancer (P = 0·023 and hazard ratio = 3·62). No significant association for TLR-4 Asp299Gly polymorphism was found. In the subgroup of patients with intestinal-type gastric cancer, a significant risk of gastric cancer was associated with TLR-4 Thr399Ile genotype (P = 0·006). Our results demonstrated that TLR-4 Thr399Ile polymorphism is linked with an increased susceptibility to gastric cancer. An increased risk for intestinal gastric cancer in carriers of the TLR4 Thr399Ile allele was observed. Future epidemiological studies should consider the possible interactions between proinflammatory genotypes (such as TLR and interleukin-1R polymorphisms) and other risk factors for cancer such as dietary habits and/or exposure to environmental carcinogens.
In a study assessing genetic diversity, 114 group A streptococcus (GAS) isolates were recovered from pediatric pharyngitis patients in Rome, Italy. These isolates comprised 22 different M protein gene (emm) sequence types, 14 of which were associated with a distinct serum opacity factor/fibronectin binding protein gene (sof) sequence type. Isolates with the same emm gene sequence type generally shared a highly conserved chromosomal macrorestriction profile. In three instances, isolates with dissimilar macrorestriction profiles had identical emm types; in each of these cases multilocus sequence typing revealed that isolates with the same emm type were clones having the same allelic profiles. Ninety-eight percent of the pharyngeal isolates had emm types previously found to be highly associated with mga locus gene patterns commonly found in pharyngeal GAS isolates.Group A streptococci (GAS) are among the most prevalent pathogens afflicting humans, causing a wide diversity of human diseases. The M protein encoded by the emm gene is a major virulence factor and provides the basis for identifying about 80 different GAS serotypes, each of which is often associated with characteristic T-antigen patterns (12). GAS are also divisible into two broad groups based on the presence or absence of serum opacity factor (Sof) activity (10,12). The inhibition of Sof activity with strain-specific antisera (anti-opacity factor typing) is another serologic tool that has been used for typing GAS for decades (14). Many strains are not precisely typeable by either M protein-or Sof protein-based serologic methods due to an array of technical problems (8). Most importantly, the majority of reference laboratories do not have the comprehensive set of typing sera necessary for this typing system.A much simpler sequence-based means for typing GAS is completely compatible with the classical M and Sof proteinbased serologic schemes (2). This system is based on sequencing the 5Ј serotype-specific end of the M protein (emm) gene (15, 16) and hypervariable portions of the sof gene.In the present study, pulsed-field gel electrophoresis (PFGE) of chromosomal macrorestriction patterns was performed to assess the genetic relatedness among GAS isolates within different emm and sof sequence types. Multilocus sequence typing (13), recently developed for studying the population genetics of GAS (7), was used to demonstrate clonality in three instances where isolates had identical emm and sof sequences but had dissimilar PFGE patterns. MATERIALS AND METHODSBacterial isolates. Throat swab specimens were obtained from persons attending two general hospitals and one pediatric hospital in Rome, Italy. One hundred fourteen GAS isolates recovered between January and March 2000 were from 114 patients with pharyngitis. The majority of GAS isolates were recovered from the pediatric hospital (101 isolates). Of the 101 patients attending the pediatric hospital, 96 lived in the central area of Italy (94 in Rome and 2 in Latina) and 5 lived in the south of Italy (4 in Na...
Three classes of macrolide resistance phenotypes and three different erythromycin resistance determinants were found among 127 erythromycin-resistant group A streptococcal (GAS) isolates recovered from 355 (35.8%) pediatric pharyngitis patients in Rome, Italy. According to emm and sof sequence typing results, erythromycin-resistant isolates comprised 11 different clonal types. Remarkably, 126 of the 127 macrolideresistant isolates were serum opacity factor (sof) gene positive. These data suggest a strong association between macrolide resistance and the presence of sof among GAS isolates recovered from Italian pediatric pharyngitis patients.
For 279 clinically isolated specimens identified by commercial kits as enterococci, genotypic identification was performed by two multiplex PCRs, one with ddl E. faecalis and ddl E. faecium primers and another with vanC-1 and vanC-2/3 primers, and by 16S ribosomal DNA (rDNA) sequencing. For 253 strains, phenotypic and genotypic results were the same. Multiplex PCR allowed for the identification of 13 discordant results. Six strains were not enterococci and were identified by 16S rDNA sequencing. For 5 discordant and 10 concordant enterococcal strains, 16S rDNA sequencing was needed. Because many supplementary tests are frequently necessary for phenotypic identification, the molecular approach is a good alternative.Identification at the species level of enterococci isolated from clinical specimens is considered necessary, as is quantitative evaluation of their resistance to penicillin, ampicillin, vancomycin, and teicoplanin and high-level resistance to gentamicin and streptomycin (11). It is also necessary to distinguish the low-virulence motile enterococcal species with constitutive low-level resistance to vancomycin from the species that are more frequently isolated from clinical specimens, such as Enterococcus faecalis and E. faecium, which in some countries can often show high-level inducible and transmissible resistance to glycopeptides (37).Commercially available kits are often used by clinical laboratories as an alternative to the numerous physiological tests needed to identify enterococcal species (6, 9, 10, 11, 37); nevertheless, all commercial kits vary in their performance and persistently show many drawbacks, especially in cases of atypical strains, and at best need supplementary manual tests, which somewhat impair their usefulness (14, 17, 23, 33, 34, 36; P. A. d'Azevedo, C. G. Dias, A. L. S. Gonçalves, F. Rowe, and L. M. Teixeira, Abstr. 100th Gen. Meet. Am. Soc. Microbiol., abstr. C-242, 2000). In some cases identification of atypical E. faecium strains may be problematic, as is distinguishing E. gallinarum from E. faecium and also identifying E. durans, E. avium, E. raffinosus, E. hirae, and E. mundtii (1, 2, 6, 7, 35, 37).In 1995 a multiplex PCR was devised for the identification of E. faecium and E. faecalis by primers targeted at specific sequences in the ddl (D-Ala-D-Ala ligase) chromosomal genes of the two species and in the glycopeptide resistance ligase genes vanA, vanB, and vanC (8). The vanC gene is present in the motile, low-level constitutive glycopeptide-resistant species E. gallinarum (vanC-1) and E. casseliflavus and E. flavescens (vanC-2/3); thus, demonstration of its presence indicates the presence of one of the aforementioned species (4,24,27,29,30).The use of a PCR with primers for ddl E. faecalis and ddl E. faecium , together with primers for vanC-1, -2, and -3, may be the most simple molecular approach for both rapid and precise identification of enterococci while avoiding the drawbacks of commercial kits. It has been succesfully used to identify vancomycin-resistant enteroco...
One hundred macrolide-resistant staphylococcal isolates from clinically relevant infections in Italy during a 19-month period were studied. Four distinct resistance phenotypes were observed using the triple-disk induction test (erythromycin, clindamycin, telithromycin): the cMLS(B) phenotype (24 isolates); the iMLS(B) phenotype (41 isolates); the MS phenotype (three isolates); and the iMTS phenotype (erythromycin-induced telithromycin resistance) (32 isolates). ermC and ermA genes predominated within erythromycin-resistant Staphylococcus aureus isolates with iMLS(B) phenotype and cMLS(B) phenotype, respectively. Among erythromycin-resistant CoNS isolates, half of the strains showed the iMTS or MS/msrA association, and ermC gene predominated among isolates with MLS(B) phenotype. By pulsed-field gel electrophoresis, high genetic heterogeneity was observed among the isolates studied. Both independent acquisition of macrolide resistance genes and spread of specific resistant clones were observed. Association between certain clonal types and specific types of infection could be detected. To our knowledge, this is the first report on characterization of erythromycin-resistant staphylococci in Italy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.