Bacillus subtilis AddAB, RecS, RecQ, PcrA, HelD, DinG, RecG, RuvAB, PriA and RecD2 are genuine recombinational repair enzymes, but the biological role of RecD2 is poorly defined. A ΔrecD2 mutation sensitizes cells to DNA-damaging agents that stall or collapse replication forks. We found that this ΔrecD2 mutation impaired growth, and that a mutation in the pcrA gene (pcrA596) relieved this phenotype.
View Article and Find Full Text PDFAimed to prevent Streptococcus pneumoniae biofilm infections, we studied the adherence of nine pneumococcal strains to polystyrene plates and on epithelial cells and the antiadhesive effect of albumin and xylitol. The adherence was variable among strains, but there was a good correlation between their adherent ability and binding to abiotic material and cells. Strains of serotypes 6B and 23F were the most adherent organisms, whereas serotype 3 strains were the least adherent.
View Article and Find Full Text PDFStreptococcus pneumoniae ability to produce biofilms may induce persistent infections and difficulties for eradication in vivo. We investigated the ability of 11 pneumococcal strains (serotypes 3, 6B, 9V, 19F, and 23F) to form biofilms on polystyrene plates at 16 and 24 h. The extent of biofilm was greater at 24 h in 10 strains, being the highest magnitude for serotype 3 strains.
View Article and Find Full Text PDFTherapeutic alternatives are needed against infections caused by highly multidrug-resistant Streptococcus pneumoniae. Novobiocin, an old antibiotic, was tested in vitro and in a murine sepsis model against one amoxicillin-susceptible and three amoxicillin-resistant strains [minimum inhibitory concentrations (MICs) 8-64 mg/L]. Novobiocin MICs for all strains were 0.
View Article and Find Full Text PDFThe in vitro activity of 22 antibiotics (including novobiocin) and beta-lactam/gentamicin combinations was assessed against 11 multidrug-resistant pneumococcal strains. Among orally administered drugs, only telithromycin, levofloxacin, and linezolid were active against all isolates, but their use is not indicated in pediatrics. Novobiocin could be a potential therapeutic alternative.
View Article and Find Full Text PDFThe in vitro activity of penicillin, ampicillin, cefditoren, cefotaxime, erythromycin, clarithromycin, and levofloxacin against 763 clinical isolates of Streptococcus pyogenes was determined. Clinically significant isolates collected from November 2005 to December 2006 in the Czech Republic, Slovakia, Hungary, Poland, Romania, Estonia, Latvia, and Lithuania (the latter 3 analyzed as Baltic countries) were studied. No resistance to beta-lactams and levofloxacin was found.
View Article and Find Full Text PDFObjectives: To study the ability of Corynebacterium urealyticum to produce biofilms and to compare the in vitro activity of antimicrobials against planktonic and biofilm-associated organisms.
Methods: Biofilm formation on polystyrene plates by three C. urealyticum strains was studied in artificial urine under static conditions.
Objectives: In an innovative therapeutic exploitation against antibiotic-resistant Streptococcus pneumoniae, here we have evaluated the in vitro activity of a purified bacterially-encoded cell wall lytic enzyme, LytA (the major pneumococcal autolysin), and compared it with those of Cpl-1 and Pal (pneumococcal phage lytic enzymes) and two antibiotics versus four pneumococcal strains.
Methods: Two serotype 3, penicillin-susceptible strains and two penicillin-resistant (serotypes 19F and 19A, respectively) S. pneumoniae clinical isolates were used.
The adherence of 11 pneumococcal strains to polystyrene was studied and expressed as the number of colony-forming units (CFU) recovered per 10(6)CFU of initial inoculum. Three strains were considered as strong adherent (>100CFU/10(6)), three as medium adherent (10-100CFU/10(6)), and five as low adherent (<10CFU/10(6)). All serotype 3 strains were low adherent whilst serotypes 23F and 19F behaved as strong or medium adherent.
View Article and Find Full Text PDFThe in vitro and in vivo antipneumococcal activities of the main pneumococcal autolysin (LytA) and Cpl-1, a lysozyme encoded by phage Cp-1, were studied. Intraperitoneal therapy with LytA or high-dose Cpl-1 remarkably reduced peritoneal bacterial counts (>5 log(10) CFU/ml) compared with those for the controls. After intravenous injection, LytA was the most effective treatment.
View Article and Find Full Text PDFThe impact of ibuprofen combined with amoxicillin or erythromycin for therapy of penicillin-resistant pneumococcal acute otitis media (AOM) was evaluated in a gerbil model. Ibuprofen (at 2.5 or 7.
View Article and Find Full Text PDFThe emergence of multidrug-resistant strains of Streptococcus pneumoniae drives the development and evaluation of new antipneumococcal agents, especially for the treatment of bacterial meningitis. The aims of the present study were to assess the antibacterial effectiveness of two new quinolones, garenoxacin (BMS; BMS-284756) and moxifloxacin (MOX) in experimental meningitis caused by a vancomycin (VAN)-tolerant S. pneumoniae strain and to compare the results with those obtained by therapy with VAN and ceftriaxone (CRO) in combination.
View Article and Find Full Text PDFA prospective study of 154 consecutive high-risk hospitalized children with lower respiratory infections was conducted to determine the clinical utility of a pneumolysin-based polymerase chain reaction (PCR) assay compared with blood and pleural fluid cultures and serological and urinary antigen tests to determine the incidence of Streptococcus pneumoniae. Whole blood, buffy coat, or plasma samples from 67 children (44%) tested positive by PCR. Sensitivity was 100% among 11 promptly tested culture-confirmed children and specificity was 95% among control subjects.
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