Inhibitory effect of streptococci on the growth of M. catarrhalis strains and the diversity of putative bacteriocin-like gene loci in the genomes of S. pneumoniae and its relatives.

S. pneumoniae is a facultative human pathogen causing a wide range of infections including the life-threatening pneumoniae or meningitis. It colonizes nasopharynx as well as its closest phylogenetic relatives S. pseudopneumoniae and S. mitis. Both the latter, despite the considerable morphological and phenotypic similarity with the pneumococcus, are considerably less pathogenic for humans and cause infections mainly in the immunocompromized hosts. In this work, we compared the inhibitory effect of S. pneumoniae and its relatives on the growth of Moraxella catarrhalis strains using the culture-based antagonistic test. We observed that the inhibitory effect of S. mitis strains is kept when a hydrogen peroxide produced by cells is inactivated by catalase, and even when the live cells are killed in chloroform vapors, in contrast to the pneumococcus whose inhibiting ability disappeared when the cells die. It was suggested that this effect may be due to the production of bacterial antimicrobial peptides by S. mitis, so we examined the genomes of our strains for the presence of bacteriocin-like peptides encoding genes. We observed that a set of bacteriocin-like genes in the genome of S. mitis is greatly poorer in comparison with S. pneumoniae one; moreover, in one S. mitis strain we found no bacteriocin-like genes. It could mean that there are probably some additional opportunities of S. mitis to inhibit the growth of competing neighbors which are still have to be discovered.

[Antibiotic Resistance of MRSA in the Russian Federation].

The results of the multicentre trial on estimation of MRSA antibiotic susceptibility to 17 antibiotics are presented. 474 nonrepeting isolates of MRSA (mecA+), collected in 2011-2014 in 10 cities of the Russian Federation were used in the trial. The antibiotic susceptibility was determined by the method of serial microdilutions in broth with estimation of the MICs in accordance with the international standards CLSI 2014 and EUCAST 2014. The highest levels of the MRSA resistance were stated against ciprofloxacin--92%(MIC50 32 mcg/ml), gentamicin--85% (MIC50 128 mcg/ml), erythromycin--54% (MIC50 32-mcg/ml) and clindainycin - 45% (MIC50 0.03 mcg/ml), as well as against rifampicin--38% (MIC50 0.06 mcg/ml). The frequency of MRSA isolated at the vancomycin dose of 2 mcg/ml equaled 26%. No correlation of the decrease in susceptibility to vancomycin and rifampicin was observed. In 5% of MRSA isolated from infected surgical wounds in patients with bone infection or sepsis, there was observed a decrease in the susceptibility to ceftarolin (MIC 2-4 mcg/ml). Co-trimoxasole, fusidic acid (MIC50 0.06 mcg/ml) and mupirocin (MIC50 0.5 mcg/ml) showed high antibacterial activity, 93-98% of the isolates being susceptible to the drugs. No resistance to linezolid and tigecycline was detected. By the associate resistance spectrum, most of the MRSA isolates were characterized by resistance to drugs of 3-7 groups (56%). The phenotypes with simultaneous resistance to drugs of 8-10 groups amounted to 6%. As a whole, 70 variants of associate resistance combinations were detected.

[Antibiotic Resistance of Coagulase-Negative Staphylococci Isolated at Hospitals of St. Petersburg and Moscow].

Antibiotic susceptibility of 119 coagulase-negative staphylococci isolated at hospitals of St. Petersburg and Moscow was investigated and estimated at the local laboratories as oxacillin resistant. The following species were identified: Staphylococcus epidermidis, S. haemolyticus, S. hominis, S.capitis, S. simulans, S. pettenkoferi, S. lentus, S. carnosus and S. warneri. The oxacillin resistance was confirmed in 79.8% of the isolates. The frequency of the associated resistance to non-beta-lactams was much higher in the oxacillin resistant isolates vs. the oxacillin susceptible ones. When the CLSI and EUCAST susceptibility criteria were used, 1-3% difference in the resistance levels was recorded. Among the oxacillin resistant isolates the frequency of resistance to gentamicin, ciprofloxacin, erythromycin, moxifloxacin, tetracycline and clindamycin equaled 90, 88, 88, 63, 43 and 26% respectively. Two linezolid resistant isolates of S. epidermidis with lower susceptibility to tedizolid were isolated. Eight isolates of S. epidermidis showed lower resistance to mupirocin. The MIC of ceftarolin for oxacillin resistant coagulase-negative staphylococci varied from 0.5 to 2.0 mcg/ml, while for the oxacillin susceptible ones it was lower than 0.25 mcg/ml. No resistance to tigecyclin and vancomycin was observed.

[Search for new modes of antibiotic prophylaxis of septic complications after percutaneous nephrolithotripsy].

The risk of infectious and inflammatory complications after PNL is based on presence of microorganisms in the form of biofilms inside the stone. Destruction of stones during surgery or lithotripsy may be a trigger for the growth of microorganisms that are integrated into the biofilms, and the migration of bacteria and their toxins in the blood flow under pressure of irrigation fluid can cause septic complications. The danger of infectious and inflammatory complications after percutaneous interventions for kidney stones requires a search for specific antibiotics for antimicrobial prophylaxis and efficient modes of their administration. The results of a comparative study of pharmacokinetic parameters of ciprofloxacin, and the effectiveness of two modes of administration (bolus dosing and prolonged intravenous administration) at a dose of 1000 mg are presented.

[Changes in body composition of oncological patients receiving nutritional support].

UNLABELLED: The article is devoted to problems of diagnostic and correction of malnutrition at patients with gastric cancer, undergoing the gastroectomy. AIMS: to study losses of body mass and dynamics of boby composition in organism of patients with gastric cancer, undergoing surgery, to estimate the efficiency of nutritional support. MATERIALS AND METHODS: open prospective cohort case-control study. Inspected 64 patients with cancer of stomach in II-IV phases, undergoing surgery. The duration of observation amounted to 12 months. 34 of these patients were obtained nutritional support (additional enteral nutrition) during 8 weeks. The efficiency of nutritional support estimated on dynamics of body mass, body composition, the content of total protein, albumin, hemoglobin, lymphocytes counts in the blood. When statistical processing of research results the non-parametric criterion of Wilcoxon for dependent samples, as well as the dispersion rank analysis of Kraskel-Walles was used. CONCLUSION: oncological process is followed by the progression of undernutrition, independently of disease stage. The nutritional support (the additional enteral nutrition) allows to substantially to improve the nutritional status of oncological patients.

[Estimation of MRSA susceptibility to oxacillin, cefoxitine, vancomycin and daptomycin].

Prevalence and therapy of infections due to MRSA remain one of the most serious problems in the world. Therefore, correct laboratory identification of the MRSA phenotype based on the use of the marker antibiotic cefoxitine, as a more susceptibile one vs. oxacillin, is of great importance. There is lately being observed a tendency towards emergence of strains with lower susceptibility to the last reserve drugs protecting from MRSA, i. e. vancomycin and daptomycin. Susceptibility of MSRA to these drugs was not investigated in Russia and there are no data on the prevalence of the VISA and hVISA phenotypes. The results of our study on estimation of susceptibility of 316 MRSA isolates from several regions of Russia to oxacillin, cefoxitine, vancomycin and daptomycin are presented herein. It was shown that the ranges of the oxacillin MIC were extremely wide, i. e. 0.5 to 512 mcg/ml, while 2.2 +/- 1% of the isolates was susceptible by the phenotype to oxacillin, in spite of the mecA gene presence. As for cefoxitine, the MRSA isolates were rather resistant to it at the MIC > 16 mcg/ml. The tests with serial microdilutions revealed that 30.7 +/- 7% of the isolates had a critical level of susceptibility to vancomycin at the MIC 2 mcg/ml. The E-tests revealed 1.3 +/- 1% of the isolates which were susceptible at the MIC 2-4 mcg/ml. The MRSA isolates were highly susceptible to daptomycin, while high levels of the MIC (2 mcg/ml) were characteristic of 2.8 +/- 1% of the isolates. Cross reduction of the susceptibility to vancomycin and daptomycin was observed.

[Genetic determinants of antibacterial resistance among nosocomial Escherichia coli, Klebsiella spp., and Enterobacter spp. isolates collected in Russia within 2003-2007].

Nosocomial bacterial isolates collected within 2003-2004 (n=411) and 2005-2007 (n=422) were highly resistant to cephalosporins III-IV and antibacterials of other groups (aminoglycosides, fluoroquinolons, chloramphenicol, and co-trimoxazole). Genes encoding TEM, SHV, CTX-M, OXA-2, and AmpC types of beta-lactamases (BLs) in the E. coli, Klebsiella spp., and Enterobacter spp. isolates were detected using polymerase chain reaction (PCR). Prevalent CTX-M-type BLs were detected in 85% of the E. coli, 87% of the Klebsiella spp., and 38% of the Enterobacter spp. isolates of the first strain collection and in 94% of the E. coli, 91% of the Klebsiella spp., and 38% of the Enterobacter spp. isolates of the second one. Genes belonging to three subtypes of blacTx-M genes were identified: bla(CTX-M-1) (228 bla(CTX-M-15) and six bla(CTX-M-3) of the first strain collection; 275 bla(CTX-M-15), three bla(CTX-M-3), and one bla(CTX-M-22) of the second one), bla(CTX-M-2) (one bla(CTX-M-5) of the first strain collection and one bla(CTX-M-2) of the second one), bla(CTX-M-9) (17 bla(CTX-M-14) and one bla(CTX-M-9) of the first strain collection; seven bla(CTX-M-14) and one bla(CTX-M-9) of the second one). Three isolates of the first strain collection and one isolate of the second one carried two genes belonging to two different subtypes, i.e., bla(CTX-M-15) and bla(CTX-M-14) simultaneously. The bacterial isolates had high levels of associative resistance to ciprofloxacin, co-trimoxazole, gentamicin, amikacin, and chloramphenicol associated with the resistance gene cassettes aadA1, aadA2, aadA5, aadB, aacA4, aac(6')Ib; dfrA1, dfrA5, dfrA12, dfrA17, cmlA1, ereA2, and catB8 in the class 1 integrons and the resistance gene cassettes dfrA1, sat1, and aadA1 in the class 2 integrons.

[Molecular genetic methods of typing of the Bartonellae].

The primer systems for the PCR detection of four house-keeping genes of bartonellae in clinical material were developed and tested. The tactics of the species RFLP typing was also developed and tested. The scheme of the species RFLP typing of bartonellae was tested using as an example two strains for the first time isolated in Russia from patients with endocarditis and fever of uncertain origin. The results of the typing were supported by sequencing of the amplicons obtained. According to the sequencing the isolates were attributed to the sub species Bartonella vinsonii, subsp. arupensis. The necessity of molecular epidemiological analysis of bartonelloses in Russia was substantiated.

[Physicochemical and antimicrobial properties of chlorine-containing compositions ciaref and DP-1]. / Fiziko-khimicheskie i antimikrobnye svoistva khlorsoderzhashchikh kompozitsii tsiaref i DP-1.

The paper presents the results of the physicochemical properties and corrosive activity of the new chlorine-containing compositions Ciaref and DP-1. Various microbiological, biochemical, and biophysical studies were conducted to examine different aspects of the mechanism of action of Ciaref and DP-1 on vegetative (Francisella tularensis) and sporal (Bacillus turingiensis) microorganisms. Suspension, test-surface irrigation, and aerosol techniques were employed under close industrial conditions to study the disinfecting properties of the agents in bacterial and sporal contamination.