The antibacterial effect of nitric oxide against ESBL-producing uropathogenic E. coli is improved by combination with miconazole and polymyxin B nonapeptide.

BACKGROUND: Nitric oxide (NO) is produced as part of the host immune response to bacterial infections, including urinary tract infections. The enzyme flavohemoglobin, coded by the hmp gene, is involved in protecting bacterial cells from the toxic effects of NO and represents a potentially interesting target for development of novel treatment concepts against resistant uropathogenic bacteria. The aim of the present study was to investigate if the in vitro antibacterial effects of NO can be enhanced by pharmacological modulation of the enzyme flavohemoglobin. RESULTS: Four clinical isolates of multidrug-resistant extended-spectrum ß-lactamase (ESBL)-producing uropathogenic E. coli were included in the study. It was shown that the NO-donor substance DETA/NO, but not inactivated DETA/NO, caused an initial growth inhibition with regrowth noted after 8 h of exposure. An hmp-deficient strain showed a prolonged growth inhibition in response to DETA/NO compared to the wild type. The imidazole antibiotic miconazole, that has been shown to inhibit bacterial flavohemoglobin activity, prolonged the DETA/NO-evoked growth inhibition. When miconazole was combined with polymyxin B nonapeptide (PMBN), in order to increase the bacterial wall permeability, DETA/NO caused a prolonged bacteriostatic response that lasted for up to 24 h. CONCLUSION: An NO-donor in combination with miconazole and PMBN showed enhanced antimicrobial effects and proved effective against multidrug-resistant ESBL-producing uropathogenic E. coli.

Multiresistant uropathogenic extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli are susceptible to the carbon monoxide releasing molecule-2 (CORM-2).

Carbon monoxide (CO) releasing molecules (CO-RMs) have been shown to inhibit growth of commensal Escherichia coli (E. coli). In the present study we examined the effect of CORM-2 on uropathogenic E. coli (UPEC) that produces extended-spectrum ß-lactamase (ESBL). Viability experiments showed that CORM-2 inhibited the growth of several different ESBL-producing UPEC isolates and that 500 µM CORM-2 had a bactericidal effect within 4 h. The bactericidal effect of CORM-2 was significantly more pronounced than the effect of the antibiotic nitrofurantoin. CORM-2 demonstrated a low level of cytotoxicity in eukaryotic cells (human bladder epithelial cell line 5637) at the concentrations and time-points where the antibacterial effect was obtained. Real-time RT-PCR studies of different virulence genes showed that the expression of capsule group II kpsMT II and serum resistance traT was reduced and that some genes encoding iron acquisition systems were altered by CORM-2. Our results demonstrate that CORM-2 has a fast bactericidal effect against multiresistant ESBL-producing UPEC isolates, and also identify some putative UPEC virulence factors as targets for CORM-2. CO-RMs may be candidate drugs for further studies in the field of finding new therapeutic approaches for treatment of uropathogenic ESBLproducing E. coli.

Decreased plasma CXCL16/SR-PSOX concentration is associated with coronary artery disease.

OBJECTIVES: To investigate for the first time whether the plasma CXCL16 concentration is altered in coronary artery disease (CAD) patients. BACKGROUND: Accumulating evidence suggests that the novel chemokine/scavenger receptor CXCL16/SR-PSOX is involved in the development of atherosclerosis and CAD. METHODS: Using ELISA we assessed the plasma CXCL16 concentration in 40 stable angina pectoris (SAP) patients, 17 unstable angina pectoris/non-ST-elevation myocardial infarction (UAP/non-STEMI) patients, 387 survivors of a first myocardial infarction (MI) and healthy control subjects (44 controls for SAP and UAP/non-STEMI patient groups and 387 controls for post-MI patients). RESULTS: SAP patients exhibited significantly lower median CXCL16 levels (2111 pg/ml) than the corresponding control subjects (2678 pg/ml) (P=0.0012). UAP/non-STEMI patients also appeared to have lower CXCL16 levels (2192 pg/ml) compared with controls (NS). Patients investigated 3 months after MI tended (P=0.07) to have lower CXCL16 levels (2529 pg/ml) than the corresponding controls (2638 pg/ml). There were no significant correlations between CXCL16 levels and different measures of CAD severity determined by quantitative coronary angiography in post-MI patients. Neither patients nor controls exhibited significant correlations between CXCL16 levels and plasma lipoprotein fractions, inflammatory cytokines, C-reactive protein or numbers of inflammatory cells in peripheral blood. CONCLUSIONS: The finding that lower plasma CXCL16 concentration is associated with CAD might indicate a potential atheroprotective function of CXCL16.