Effect of polyenic antibiotics on the activity of alkaline phosphatase from Candida albicans]

Polyenic antibiotics (levorin, amphotericin B, nistatin) inhibit in vivo and in vitro the activity of membrane alkaline phosphatase from sensitive Candida albicans strain, and their inhibitory effect is twice lower on the enzyme from the resistant strain. A correlation is observed between the antibiotic concentration and the inhibitory effect on alkaline phosphatase activity. Nistatin is found to be the least efficient inhibitor (among the antibiotics studied) of alkaline phosphatase. The treatment of membranes with polyenic antibiotics does not result in solubilization of membrane proteins nad alkaline phosphatase. The data obtained are considered with respect to the effect of polyenic antibiotics on cell membrane structure.     

Sensitivity to antibiotics of Clostridium difficile toxigenic nosocomial strains

Clostridium difficile is the etiological agent of diarrhoea and colitis, especially in elderly patients. The incidence of these diseases has increased during the last 10 years. Emergence of so-called hypervirulent strains is considered as one of the main factors responsible for the more severe disease and changed profile of sensitivity to antimicrobial agents. The aim of this work was to determine the sensitivity profile of toxigenic strains of C. difficile in the Czech Republic in 2011–2012 to selected antibiotics. The antibiotics clindamycin, metronidazole, vancomycin and amoxicillin with clavulanic acid were used for this purpose. Isolates cultured on Brazier's C. difficile selective agar were analysed for the presence of toxin genes using Xpert detection system. Xpert analysis revealed that 33 strains carried the genes for toxins tcdB, cdt and tcdCΔ117, thus showing characteristics typical for the hypervirulent ribotype 027/PFGE type NAP1/REA type B1. The remaining 29 strains carried only the gene for toxin B (tcdB) and not cdt and tcdCΔ117. Our results indicate the higher susceptibility of C. difficile hypertoxigenic strains to three out of four tested antibiotics (except vancomycin) than it is for the other toxigenic strains. We found that only 10.34 % of other toxigenic strains were resistant to clindamycin, and no resistance was found in all other cases. All the isolates were sensitive to amoxicillin/clavulanic acid in vitro. However, its use is not recommended for therapy of infections caused by C. difficile.     

Antifungal activity of clinical Lactobacillus strains against Candida albicans biofilms: identification of potential probiotic candidates to prevent oral candidiasis

This study isolated Lactobacillus strains from caries-free subjects and evaluated the inhibitory effects directly on three strains of C. albicans, two clinical strains and one reference strain. Thirty Lactobacillus strains were isolated and evaluated for antimicrobial activity against in vitro C. albicans biofilms. L. paracasei 28.4, L. rhamnosus 5.2 and L. fermentum 20.4 isolates exhibited the most significant inhibitory activity against C. albicans. Co-incubation between these microorganisms resulted in deterrence of biofilm development and retardation of hyphal formation. The hindrance of biofilm development was characterized by the downregulated expression of C. albicans biofilm-specific genes (ALS3, HWP1, EFG1 and CPH1). L. paracasei 28.4, L. rhamnosus 5.2 and L. fermentum 20.4 demonstrated the ability to exert antifungal activity through the inhibition of C. albicans biofilms.     

Simultaneous carriage of Candida albicans strains from HIV-infected patients with oral candidiasis: multilocus enzyme electrophoresis analysis

Abstract Genetic diversity of 160 Candida albicans isolates from the oral cavity of 16 HIV-infected adults prior to antifungal treatment was assessed using multilocus enzyme electrophoresis (10 C. albicans colonies were randomly chosen from each specimen culture). 20 electrophoretic types were distinguished from the analysis of 21 enzyme loci (10 were polymorphic). Five patients (31%) were found to be colonized by 2 or 3 genetically distinct strains. Nevertheless, in these five cases, one strain predominated (from 7 to 9 of the 10 colonies). Some HIV + patients with oral candidiasis appear to be simultaneously infected with several genetically different C. albicans strains before antifungal treatment.     

Sensitivity of clinical Proteus strains to antibiotics and their combinations]

In 1976 isolation of Proteus from wounds of patients with various purulent processes amounted to 14.5 per cent. Serotypes 0-10, 0-3 and H-3 predominated among the isolates. Sensitivity of 35 clinical strains of Proteus to 10 antibiotics, furagin and nevigramone was studied by the method of serial dilutions in liquid media. All the isolates were highly resistant to the antibiotics except gentamicin, furagin and nevigramone, the MIC of which for most of the strains was 3.12, 1.6-3.12 and 6.25-12.5 gamma/ml, respectively. The effect of 14 combinations of chemotherapeutics was also studied. The combinations of gentamicin with carbenicillin, gentamicin with ampicillin and monomycin with ampicillin proved to be most effective against the Proteus strains tested. The following combinations may be of practical value: monomycin + carbenicillin, kanamycin + ampicillin, kanamycin + carbenicillin, ampicillin + furagin, gentamicin + nevigramone. The combinations of carbenicillin with furagin and gentamicin with furagin were also rational.     

Sensitivity of antibiotic-resistant strains of Salmonella to new antibiotics and chemotherapeutic agents]

One hundred and sixty two antibiotic resistant strains of Salmonella isolated within 1984-1988 in Leningrad and the Leningrad Region were tested with respect to their sensitivity to new antibiotics and chemotherapeutics developed or being developed in the USSR. At the background of high numbers of circulating Salmonella strains resistant to the routinely used antibiotics such as doxycycline, streptomycin and gentamicin they appeared to be highly sensitive to amikacin, ciprofloxacin, pefloxacin and the 3rd generation cephalosporins i.e. ceftazidime and cefotaxime as well as to thienamycin. These modern antibacterial agents are possibly to be the drugs of choice in etiotropic treatment and chemoprophylaxis of septic acute intestinal infections due to Salmonella strains with multiple resistance. Resistance of individual Salmonella strains to cefotaxime and ceftazidime indicated that it was possible to use their property for additional labeling of the pathogens within a serological type of Salmonella while conducting epidemiological examinations during outbreaks of acute intestinal infections of Salmonella etiology.     

Sensitivity of methicillin-resistant Staphylococcus aureus strains to some antibiotics, antiseptics and disinfectants

The effects of antibiotics, antiseptics and disinfectants against some methicillin resistant (MRSA) and methicillin-sensitive (MSSA) Staphylococcus aureus strains have been studied. The MRSA and MSSA strains were equally sensitive to phenols, esters of para(4)-hydroxybenzoit acid and chlorhexidine but MRSA strains were slightly more resistant to quaternary ammonium compounds and considerably more so to dibromopropamidine isothionate. Some MRSA strains were also resistant to phenylmercuric nitrate (but not another organomercurial, thiomersal), mercuric chloride and cadmium chloride. All MRSA strains produced β-lactamase. Strains from the Royal Free Hospital, London were highly resistant to β-lactam antibiotics, erythromycin, trimethoprim and tetracyctines but were sensitive to other antibiotics. One strain from the University Hospital of Wales, Cardiff was resistant to gentamicin but sensitive to tetracycline and trimethoprim.     

Sensitivity of methicillin-resistant Staphylococcus aureus strains to some antibiotics, antiseptics and disinfectants

The effects of antibiotics, antiseptics and disinfectants against some methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) Staphylococcus aureus strains have been studied. The MRSA and MSSA strains were equally sensitive to phenols, esters of para(4)-hydroxybenzoic acid and chlorhexidine but MRSA strains were slightly more resistant to quaternary ammonium compounds and considerably more so to dibromopropamidine isothionate. Some MRSA strains were also resistant to phenylmercuric nitrate (but not another organomercurial, thiomersal), mercuric chloride and cadmium chloride. All MRSA strains produced beta-lactamase. Strains from the Royal Free Hospital, London were highly resistant to beta-lactam antibiotics, erythromycin, trimethoprim and tetracyclines but were sensitive to other antibiotics. One strain from the University Hospital of Wales, Cardiff was resistant to gentamicin but sensitive to tetracycline and trimethoprim.