Random amplified polymorphic DNA typing versus pulsed-field gel electrophoresis for epidemiological typing of vancomycin-resistant enterococci.

Sixty vancomycin-resistant vanA mutant Enterococcus faecium (VRE) isolates, collected during a 40-month period from 48 patients hospitalized in a French Cancer Referral Center, were typed by using random amplified polymorphic DNA (RAPD), and the results were compared with those previously obtained by typing with SmaI pulsed-field gel electrophoresis (PFGE), which is currently recognized as the "gold standard." The discriminating power of RAPD typing, with seven primers and 11 combinations of primers, was tested on 18 strains, and only the most discriminating combination was further tested on the whole collection. We compared the epidemiological usefulness of RAPD typing of 60 clinical VRE isolates with that of SmaI PFGE typing. With primers AP4 and ERIC1R, RAPD generated 30 patterns versus the 36 patterns generated by SmaI PFGE. However, this did not hamper the epidemiologically correct clustering of 15 related strains and the detection of multiple colonization in nine patients. We conclude that this simple RAPD technique is well suited to the epidemiological typing of VRE and the monitoring of its nosocomial spread.     

Comparative translocation of enteropathogenic Campylobacter spp. and Escherichia coli from the intestinal tract of gnotobiotic mice.

In C3H gnotobiotic mice, no significant difference was observed between the translocation of nine clinical isolates of enteropathogenic Campylobacter spp. and that of seven nonisogeneic Escherichia coli strains with or without various determinants of pathogenicity. In addition, there was no correlation found between the intensity of translocation of Campylobacter strains and the signs of invasiveness in the patients from whom the strains had been isolated.     

Liposomes and Nanoparticles in the Treatment of Intracellular Bacterial Infections

The treatment of infections caused by obligate or facultative intracellular microorganisms is difficult because most of the available antibiotics have either poor intracellular diffusion and retention or reduced activity at the acidic pH of the lysosomes. The need for antibiotics with greater intracellular efficacy led to the development of endocytosable drug carriers, such as liposomes and nanoparticles, which mimic the entry path of the bacteria by penetrating the cells into phagosomes or lysosomes. This Review assesses the potential of liposomes and nanoparticles in the targeted antibiotic therapy of intracellular bacterial infections and diseases and the pharmaceutical advantages and limitations of these submicron delivery systems.     

Consequences of antibiotic therapy to the intestinal ecosystem

Ecological impact of antibiotherapy results from the interaction between microorganisms in the ecosystems and antibiotics at which they are exposed. The amount of antibiotics use in the world is continuously increasing. The fraction devoted to human care is only about half the total amount. There are multiple other fields of usage, in agriculture, breeding and veterinary medicine. Bacterial ecosystems exposed at antibiotherapy in man are mainly the skin and the gastrointestinal and respiratory tracts. The gastrointestinal system is quantitatively predominant and the consequences of the bacterial imbalance induced by antibiotics are potentially severe. It is the reason why it is the most extensively studied, in the literature and in the present review. The origin of resistant bacteria will be briefly discussed.     

Enterobacteriaceae bacteremia: Risk factors for ESBLPE

Objectives

The increasing prevalence of extended spectrum beta-lactamase producing enterobacteriaceae (ESBLPE) requires defining the use of carbapenems in first intention. We analyzed the associations between enterobacteriaceae bacteremia (EbBact) and ESBLPE carriage during 10 years in a 950-bed teaching hospital.

Methods

We analyzed a 10-year (July 2001 to June 2011) prospective collection of bacteremia cases including 2 databases: (1) EbBact and (2) a computerized database of patients carrying EBLSE. Only one episode of EbBact was analyzed per patient and hospital stay. Factors associated with ESBLPE bacteremia were assessed by univariate and multivariate logistic regression analysis.

Results

Overall, 2355 cases of EbBact were identified, among which 135 (5.7%) were ESBLPE (2001–05: 1.4%, 2006–09: 7.6%, 2010–11: 14.2%). ESBLPE bacteremia was observed in 52 of the 88 (59%) patients carrying ESBLPE and in 83/2267 (3.7%) patients not known to be colonized with ESBLPE. Factors associated with ESBLPE bacteremia in patients not known to be colonized were: female gender (ORa = 0.56, CI95% [0.34–0.91]), hospitalization in the ICU (ORa = 2.51 [1.27–5.05]) or medical/surgical wards (ORa = 1.83 [1.04–3.38]), the period (2006–09, ORa = 4.08 [2.21–8.16]; 2010–11, ORa = 8.17 [4.14–17.06] compared to 2001–05), and history of EbBact (ORa = 2.29 [0.97–4.79]).

Conclusion

In case of EbBact, patients known to be colonized with ESBLPE present with ESBLPE bacteremia in more than half of the cases, requiring carbapenems as empirical antibiotic treatment. The global prevalence of ESBLPE among patients presenting with EbBact not known to be colonized with ESBLPE was 3.7%.     

Intranasal immunization with protein-linked phosphorylcholine protects mice against a lethal intranasal challenge with streptococcus pneumoniae

Immunization against phosphorylcholine (PC) linked to a protein protects mice against Streptococcus pneumoniae when used parenterally, and against Salmonella typhimurium when used orally after entrapment in D,L-Lactide-co-Glycolide microspheres. Here, we immunized BALB/c mice intranasally with a serotype 3 S. pneumoniae strain. Immunization was followed by a rise in anti-PC IgA and IgG titers in serum and in pulmonary secretions, but not by any rise in anti ds-DNA antibody nor any glomerular Ig deposition. The survival rates were 91 and 76% in the two groups of mice, respectively. These rates were significantly higher than those in control mice immunized intranasally either with Thyr loaded in microspheres (0%), blank microspheres (22%), free Thyr (17%), and saline (18%). This demonstrates that the mucosal route is effective for vaccination against S. pneumoniae pneumonia with PC linked to a protein carrier. It constitutes another important step forward in the development of the concept that PC can be used as a mucosal immunogen for protection against the different diseases caused by PC-bearing bacteria.     

Molecular typing of multiresistant Klebsiella pneumoniae isolated from children from northern Jordan

Twenty-nine clinical isolates of community acquired Klebsiella pneumoniae obtained from 17 children with malnutrition were characterized by antibiotic susceptibility, plasmid analysis, and random amplified polymorphic DNA (RAPD) techniques. Disc diffusion methodology was used to test the susceptibility of the isolates to 13 antibiotics: amoxycillin, cephapirin, ceftazidime, cefoxitin, cefotaxime, aztreonam, gentamicin, ciprofloxacin, chloramphenicol, erythromycin, nalidixic acid, trimethoprim and amoxycillin-clavulanic acid. All the isolates showed multiresistance patterns (15 patterns) ranging from resistance to two antibiotics to resistance to 10 antibiotics. All isolates were resistant to amoxycillin and erythromycin. Ten K. pneumoniae isolates producing extended-spectrum beta-lactamases (ESBLs) as evidenced by the double-disc diffusion synergy test were isolated sporadically from six patients. Six of these 10 isolates were hyperproducers of ESBL, which resulted in increased resistance to the beta-lactam-beta-lactamase inhibitor combination amoxycillin-clavulanic acid. Plasmid analysis showed plasmid ranging in size from 48 kilobases (kb) to 1.4 kb. All the 29 isolates shared the same plasmid 26 kb. There was a consistent relationship between antibiotype and plasmid profiles for each pair of isolates obtained from five individual patients. RAPD analysis using a single (10-mer) primer demonstrated that the isolates that have the same antibiotype and the same plasmid profile had different RAPD fingerprint patterns. These results demonstrate that the RAPD technique is better than antibiotype characterization and a plasmid analysis profile for typing K. pneumoniae as well as for revealing strain differences.     

In vitro and in vivo evaluation of pectin beads for the colon delivery of beta-lactamases

The aim of the present study was to provide a "proof of concept" of colon delivery of beta-lactamases by pectin beads aiming to degrade residual beta-lactam antibiotics, in order to prevent the emergence of resistant bacterial strains.Pectin beads were prepared according to ionotropic gelation method using CaCl2 as a gelling agent. Particles were then washed and soaked in polyethylenimine (PEI). Coating beads with PEI considerably improved their stability in simulated intestinal medium. In vitro studies showed that beta-lactamases were released from pectin beads in colonic medium due to the action of pectinolytic enzymes. When ampicillin was added to this medium, the release of beta-lactamases induced, as expected, the antibiotic inactivation. Finally, after oral administration of loaded-beads to CD1 mice, beta-lactamases were retrieved in high concentrations in faeces. Observation by SEM of beads extracted from mice intestinal tracts concluded the core degradation of beads without any modification of the PEI coating layer.This study demonstrates that a multiparticulate system with suitable characteristics for site-specific colonic delivery can be prepared. This system could be used to target beta-lactamases to the colon in order to hydrolyse antibiotic residues during treatment and prevent their impact on colonic microflora.     

Prospective evaluation of virulence factors of enterococci isolated from patients with peritonitis: impact on outcome

The objective of this study was to evaluate the prevalence of 4 virulence factors (VFs) of enterococci (cytolysin [cyl], gelatinase [gel], aggregation substance [agg], and enterococcal surface protein [esp]) and their relationship to outcome in patients with generalized peritonitis in a prospective cohort study. VF expression in each strain was assessed by polymerase chain reaction assay with specific primers. Outcome of the patients was recorded. Ninety-nine strains of Enterococcus were obtained from the peritoneal fluid of 81 patients. Fifty-eight patients had at least 1 strain bearing [cyl] (13.1% of the strains), [gel] (50.5% of the strains), [agg] (40.4% of the strains), and [esp] (34.3% of the strains). The presence of VF of Enterococcus was independently associated with mortality: odds ratio, 5.5; 95% confidence interval, 1.3-28.1. In conclusion, VF accounted for 72% of the patients with enterococci isolated from the peritoneal fluid and was independently associated with mortality in severe peritonitis.