RESUMO
Escherichia coli is the most common cause of Gram-negative peritonitis resulting in peritoneal function deterioration as well as poor clinical outcome in continuous ambulatory peritoneal dialysis (PD) patients. In this study, we analyzed the phylogenetic background and genetic profile of the E. coli isolates and sought to determine the characteristics of specific bacteria associated with peritonitis. E. coli isolates from 56 episodes of peritonitis in 46 PD patient cases and rectal isolates from 57 matched PD control patient cases were compared for both phylogenetic groups and the presence of virulence factors (VFs). There were no significant differences in terms of demographic data between the peritonitis and control groups. Peritonitis isolates exhibited a significantly greater prevalence of 8 VFs. In multivariate logistic regression analysis, kpsMT II (group 2 capsule synthesis) was the strongest VF predictor of peritonitis (OR = 8.02; 95%CI = 3.18-20.25; P < 0.001), followed by traT (serum-resistance-associated outer membrane protein) (OR = 3.83; 95%CI = 1.33-11.03; P = 0.013). The pathogenic groups of E. coli contained a higher concentration of individual VFs compared to the commensal groups. The prevalence of pathogenic E. coli was much higher in peritoneal isolates than rectal isolates (64.3 vs 31.6%, P = 0.001). Our results indicate that the E. coli peritonitis and rectal isolates are different in PD patients. The specific VFs associated with peritonitis isolates may directly contribute to the pathogenesis of peritonitis.
Assuntos
Escherichia coli/genética , Peritonite/microbiologia , Adulto , Escherichia coli/classificação , Escherichia coli/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Diálise Peritoneal/métodos , Filogenia , Fatores de VirulênciaRESUMO
The associations between single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) and cancer risk and disease outcome have been extensively analyzed. We investigated the association between age-at-onset and SNPs in the mitochondrial D-loop using a population-based series of non-small cell lung cancer (NSCLC) patients. The D-loop region of mtDNA from NSCLC patients was amplified and sequenced. The age-at-onset curve of NSCLC patients was calculated using the Kaplan-Meier method at each SNP site and values were compared using the log-rank test. The SNP sites of nucleotides 200G/A and 16362T/C were identified to determine their association with age-at-onset of NSCLC using the log-rank test. The nucleotide 207G/A was identified for its association with age-at-onset at a borderline significance level (P = 0.060). We found that genetic polymorphisms in the D-loop were predictive markers for age-at-onset in NSCLC patients. Accordingly, the analysis of genetic polymorphisms in the mitochondrial D-loop can be used to identify NSCLC patient subgroups at high risk of early onset.