[The evaluation of effectiveness of application of automated system of polymerase chain reaction to detect meticillin-resistant and meticillin-sensitive Staphylococcus aureus in clinical material from trauma orthopedic patients].

The article considers the evaluation of effectiveness of application of automated polymerase chain reaction system GeneXpert DX ("Cepheid USA) as compared with bacteriologic method in detection of S. aureus (SA) and meticillin-resistant S. aureus (MRSA) under infection of skin and soft tissues in orthopedic patients. The results of analysis of material from patients got in 2009-2011 using analyzer Vitek-2 to identify microorganisms demonstrated that separation and identification of agent was successful in 70.04% of 2153 examined samples. The representatives of genus of Staphylococcus made up 56% of strains. The percentage of MSRA consisted 29.8% of SA isolates. In 2012, the GeneXpert DX system was used to analyze 50 samples of clinical material. The analysis established full matching of results of detection of SA/MRSA in case of using this method and bacteriological analysis to detect agent. The DNA of SA was detected in 61.5% of patients in whom the application of bacteriological method was unsuccessful in separation and identification of agent. In 25% of patients DNA of MRSA was detected. This occurrence made it possible to begin corresponding therapy and to get clinical effect. The diagnostic using GeneXpert DX system took less than 1.5 hours from moment of availability of sample in laboratory. The application of polymerase chain reaction system GeneXpert DX is an effective additional method to identify SA/MRSA which does not exclude application of bacteriological analysis.

[Estimation of species diversity of coagulase-negative staphylococci isolated in hospitals of Russian Federation in 2009-2010].

AIM: Comparative analysis of species diversity of sample of coagulase-negative staphylococci (CNS) isolated in hospitals of different specializations. MATERIALS AND METHODS: For identification of 102 CNS strains, biochemical systems manufactured by NPO "Diagnostic Systems", VITEK 2 Compact, and BBL Crystal as well as sequencing of fragments of tuf and gap genes were used. RESULTS: Greater differentiating capability of genotyping compared with phenotyping methods for species identification of staphylococci was demonstrated. Six CNS species were identified in the sample: S. epidermidis, S. haemolyticus, S. hominis, S. warneri, S. capitis, and S. pasteuri. The largest species diversity was noted for strains from maternity hospitals in Nizhny Novgorod and Kulakov Scientific Center for Obstetrics, Gynecology and Perinatology. Strains isolated from blood of patients in Bakulev Center for Cardiovascular Surgery were represented mostly by S. epidermidis and S. haemolyticus. Differences in species diversity of CNS--causative agents of neonatal conjunctivitis and omphalitis--were observed. CONCLUSION: Two species of CNS: S. epidermidis and S. haemolyticus pose special threat as nosocomial pathogens both in hospitals for adults and obstetrical facilities. Additionally, in neonatal units it is necessary to control such species as S. warneri, S. capitis, S. pasteuri.

[Isolation rate of enterotoxigenic staphylococci in patients with sepsis, pneumonia and burns].

The occurrence of Staphylococcus aureus strains producing enterotoxins of types SEA and SEB, which isolated from patients of different profile and caused the infectious process accompanied by pronounced intoxication without vomiting and enteric disturbances, was determined by means of the indirect hemagglutination test. The collection included 28 strains isolated in sepsis, 38 strains isolated in pneumonia, 57 strains isolated from patients with burns and 23, from the hands and nasopharynx of the medical staff. Among the staphylococcal strains isolated in sepsis, 75.6% synthesized SEA and 5.4%, SEB. The occurrence of SEA- and SEB-positive strains isolated in pneumonia was, respectively, 42.1% and 2.6%. From patients with burns SEA-positive staphylococci were mainly isolated (92.9%). Only 3% of the cultures isolated in wound infections produced SEA. From the medical staff, 13.4% of SEA-positive strains and 17.3% of SEB-positive strains were isolated. The data obtained from this study indicate the expediency of the determination of the enterotoxigenic properties of S. aureus clinical isolates in medical institutions for prophylactic measures with a view to the prevention of the spread of pathogenic clones.

[Study on the polymorphism of the coagulase gene by the method of sequencing in methicillin-resistant Staphylococcus aureus strains, isolated in hospitals in different regions of Russia and Belarus].

This method was used for typing of 31 Staphylococcus aureus methicillin-resistant (MRSA) strains; of these, 27 were clinical isolates obtained in hospitals of different cities of Russia and Belarus and 4 were international epidemic strains EMRSA-1, -2, -3, -12. The sequencing of the variable area, located in the middle part of the coagulase gene between nucleotides 979-1355 and detected with the use of information technologies, was carried out. The results of this sequencing were compared with those of the earlier study on the polymorphism of the area of the same gene between nucleotides 1513-2188, carried out by the method of PCR-restrictive fragment length polymorphism. The sequencing of the part of the coagulase gene made it possible to confirm the presence of essential differences in the nucleotide sequences of the coagulase gene in international strains EMRSA-1, -3, -12, grounds for classifying clinical isolates of MRSA strains with two groups (4 and 5), as well as the genetic relationship of different phage types, isolated in different clinics. The study revealed considerable similarity in the nucleotide composition of strains EMRSA-2 and EMRSA-12 despite the fact that, according to the results of Cfol restriction of the 3'-end, they were classified with different groups; the study also revealed the identity of the nucleotide sequences of the coagulase gene in the cultures of group 5, isolated in hospitals of Moscow, St. Petersburg, Orenburg, and strain EMRSA-2, as well as methicillin-sensitive S. aureus strain 8325-4; in addition, in clinical isolates of group 4 and strain EMRSA-1 a considerable degree of homology was revealed. The study of two different loci made it possible to find out the strain with the recombinant form of the coagulase gene. The approach used in this study permitted the differentiation of the international epidemic strains EMRSA-1, -2, -3 and -12 into individual groups, which coincided with the results of Enright et al. (2002) who used multilocus sequencing.

[Molecular epidemiology of infections caused by methicillin-resistant staphylococci]. / Molekuliarnaia épidemiologiia infektsii, vyzyvaemykh metitsillin-ustoichivymi stafilokokkami.

The review deals with the periodicity of the spread of methicillin-resistant S. aureus (MRSA) strains during the last 40 years, the mechanism of their resistance to methicillin and other beta-lactamic antibiotics, the genetic control of methicillin resistance, the genome organization of mec DNA and its possible cause, as well as the organization of epidemiological surveillance on MSRA in hospitals. The problem of changes in the epidemiology of staphylococcal infections due to the appearance of MRSA in the absence of contacts with carriers, treatment with antibiotics or stay in a hospital is discussed. The concern of public health authorities in connection with the emergence of MRSA strains, moderately resistant or resistant to vancomycin, is also discussed. The most promising programs of the MRSA study, as well as the optimum programs introduced in economically developed counties for the control of hospital infections caused by MRSA, are considered.

[Evaluation of the usefulness of three collections of bacteriophages for typing methicillin-resistant Staphylococcus aureus, isolated in Moscow hospitals]. / Sravnitel'naia éffektivnost' tipirovaniia tremia kollektsiiami bakteriofagov shtammov metitsillinrezistentnykh Staphylococcus aureus, vydelennykh v statsionarakh g. Moskvy.

The typing of S. aureus methicillin-resistant strains, isolated in different hospitals of Moscow; was carried out with the use of three collections of phages: the International Set of Phages; the set of phages of the International Center of S. aureus phage typing in London (L); and the experimental collection of phages of the Gamaleya Institute of Epidemiology and Microbiology in Moscow (M). In this study made with the use of both the phages of the International Diagnostic Set and phages L in the standard typing dose of 1 TP about 6% of the cultures under study proved to be sensitive. When the typing dose was increased to 100 TP the phages of the international diagnostic set lyzed 75.5% of the cultures. The typed strains were found to belong to phage types 77 (71.7%), 77/84/85 (19.6%) and 94/96 (6.5%). At a concentration of 100 TP phages L lyzed 83.7% of the cultures, but the dominating phage types could not be determined due to a great variety of phage markers. In contrast to the two preceding collections, the third phage collection M was composed in such a way that in the study of the investigated culture the specificity of its restriction modification was primarily evaluated and only then the presence of antiphage immunity was determined. This latter collection was used in the evaluation of 93.1% of the cultures. By the specificity of their restriction specification system the majority of them were classified with two new groups, heretofore not described. Only this collection M made it possible to differentiate epidemic and sporadic strains and to evaluate the epidemic situation in all 6 hospitals.

[Comparative findings on the stability of plasmid resistance to antibiotics in vitro and in vivo]. / Sravnitel'nye dannye o stabil'nosti plazmidnoi ustoichivosti k antibiotikam in vitro i in vivo.

The authors carried out comparative study of the incidence of spontaneous plasmide-negative variants occurrence in the S. aureus 8325phi IIde population developing under various conditions in vitro and in vivo. The mean percentage of such variants in the population developing in vitro constituted 0.9 +/- 0.2 in broth, 1.2 +/- 0.3 in the exudate, 6.3 +/- 2.0 in the population developing in vivo in the subcutaneous purulent-inflammatory focus, 9.5 +/- 2.6 in the kidneys. The mean percentage of plasma-negative variants in the purulent exudate in vivo was significantly greater than in the purulent exudate in vitro. The incidence of negative variants occurrence in vivo depended on the macroorganism properties.