b Polymyxins, which are increasingly being used to treat infections caused by multidrug-resistant bacteria, perform poorly against Serratia marcescens. To investigate the underlying mechanisms, Tn5 mutagenesis was performed and two mutants exhibiting increased polymyxin B (PB) susceptibility were isolated. The mutants were found to have Tn5 inserted into the arnB and arnC genes. In other bacteria, arnB and arnC belong to the seven-gene arn operon, which is involved in lipopolysaccharide (LPS) modification. LPSs of arn mutants had greater PB-binding abilities than that of wild-type LPS. Further, we identified PhoP, a bacterial two-component response regulator, as a regulator of PB susceptibility in S. marcescens. By the reporter assay, we found PB-and low-Mg 2؉ -induced expression of phoP and arn in the wild-type strain but not in the phoP mutant. Complementation of the phoP mutant with the full-length phoP gene restored the PB MIC and induction by PB and low Mg 2؉ levels, as in the wild type. An electrophoretic mobility shift assay (EMSA) further demonstrated that PhoP bound directly to the arn promoter. The PB challenge test confirmed that pretreatment with PB and low Mg 2؉ levels protected S. marcescens from a PB challenge in the wild-type strain but not in the phoP mutant. Real-time reverse transcriptase-PCR also indicated that PB serves as a signal to regulate expression of ugd, a gene required for LPS modification, in S. marcescens through a PhoP-dependent pathway. Finally, we found that PB-resistant clinical isolates displayed greater expression of arnA upon exposure to PB than did susceptible isolates. This is the first report to describe the role of S. marcescens arn in PB resistance and its modulation by PB and Mg 2؉ through the PhoP protein.
Lacking virulence genes examined, genetic diverse E. coli isolates are unrelated to human pathogenic E. coli. Enhancing sanitation in milk processing and transportation is needed to eliminate multidrug-resistant (MDR), fluoroquinolone-resistant, and ESBL-producing E. coli isolates.
This study applies social support theory to the question of whether four types of husband behavior (taking the wife's side, problem solving, ignoring conflict, and taking the mother's side) moderate the association between conflict with the mother-in-law and a Taiwanese woman's marital satisfaction. Data were collected from 125 married Taiwanese women. The results of hierarchical regression analyses indicate a significant negative main effect of conflict with the mother-in-law on the wife's marital satisfaction. This main effect is moderated by two types of husband behavior. When wives reported that their husbands frequently took their side or used problem-solving strategies to the conflict, conflict is not significantly related to the wives' marital satisfaction. The conflict and the two types of husband behavior accounted for 32% to 38% of the variance in wives' marital satisfaction.
Background
Insulin resistance (IR) is a known risk factor for cardiovascular disease (CVD) in non-diabetic patients through the association of hyperglycemia or associated metabolic factors. The triglyceride glucose (TyG) index, which was defined by incorporating serum glucose and insulin concentrations, was developed as a surrogate marker of insulin resistance. We aimed to investigate the association between the TyG index and the early phase of subclinical atherosclerosis (SA) between the sexes.
Methods
The I-Lan Longitudinal Aging Study (ILAS) enrolled 1457 subjects aged 50–80 years. For each subject, demographic data and the TyG index {ln[fasting triglyceride (mg/dL) × fasting plasma glucose (mg/dL)]/2} were obtained. Patients were further stratified according to sex and the 50th percentile of the TyG index (≥ 8.55 or < 8.55). SA was defined as the mean carotid intima-media thickness (cIMT) at the 75th percentile of the entire cohort. Demographic characteristics and the presence of SA were compared between the groups. Logistic regression analysis was performed to assess the relationship between TyG index and SA.
Results
Patients with a higher TyG index (≥ 8.55) had a higher body mass index (BMI), hypertension (HTN) and diabetes mellitus (DM). They had higher lipid profiles, including total cholesterol (T-Chol) and low-density lipoprotein (LDL), compared to those with a lower TyG index (< 8.55). Gender disparity was observed in non-diabetic women who had a significantly higher prevalence of SA in the high TyG index group than in the low TyG index group. In multivariate logistic regression analysis, a high TyG index was independently associated with SA in non-diabetic women after adjusting for traditional risk factors [adjusted odds ratio (OR): 1.510, 95% CI 1.010–2.257, p = 0.045] but not in non-diabetic men. The TyG index was not associated with the presence of SA in diabetic patients, irrespective of sex.
Conclusion
A high TyG index was significantly associated with SA and gender disparity in non-diabetic patients. This result may highlight the need for a sex-specific risk management strategy to prevent atherosclerosis.
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