[Detection of the genes of pyrogenic toxins of superantigens in clinical isolates of methicillin resistant Staphylococcus aureus].

The content of methicillin resistant S. aureus (MRSA) genes, coding the synthesis of staphylococcal enterotoxins A, B, C (sea, seb, sec) and the toxin of the toxic shock syndrome (tst-H) which was classified with pyrogenic toxins of superantigens (PTSAgs), was studied with the use of PCR amplification. The study revealed the specific features of the content of genes sea and sec, detected in epidemic strains, identified earlier and found to circulate in Russian hospitals. Among the isolates, genetically related to international epidemic strain EMRSA-1, isolates containing no gene sea were detected, while among the isolates genetically related to strain EMRSA-2, isolates containing not only gene sea, but also gene sec were detected, which was indicative of the tendence of this epidemic strain in the direction of further acquisition of pathogenicity genes. As revealed in further studies, among the cultures obtained in bacteriemia, 88% contained gene sea. Two out of three isolates obtained from patients with the symptoms of toxic shock also contained this gene. The differences in the content of genes PTSAgs (sea, seb, sec and tst-H) could serve as a genetic criterium for the differention of isolates circulating in a hospital, as well as for a more complete characterization of the epidemic strains MRSA. The determination of the given genetic markers in genetic strains in circulating strains will make it possible to prognosticate the structure, severity and outcomes of hospital infections. The conditions of PCR amplification for the determination of genes sea, seb, sec and tst-H, as well as multiplex PCR for the determination of genes sea and seb, were developed.

[Etiology of severe hospital infections in intensive care units and antibiotic resistance of pathogens].

The leading pathogens of severe infections in intensive care units were the following: respiratory tract infections--bacteria of the famility of Enterobacteriaceae (33.8%), Pseudomonas spp. (24.9%), Acinetobacter spp. (18.1%), Staphylococcus aureus (16.0%), blood flow infections--coagulase negative staphylococci (33.6%), S. aureus (26.1%), Enterobacteriaceae (17.6%), wound infections--Enterobacteriaceae (35.7%), coagulase negative staphyloccocci (17.8%), Pseudomonas spp. (14.3%). As for various species of Enterobacteriaceae, susceptibility was preserved in 91-100% of the isolates to meropenem, in 72-100% to cefoperazone/sulbactam, in 51-65% to cefepime, in 72-86% to amikacin, and in less than 50% to cephalosporins and fluoroquinolones. As for P.aeruginosa, 28% of the isolates was resistant to all the antibacterials, except polymyxin. The highest susceptibility to cefoperazone/sulbactam and meropenem was revealed in the isolates of Acinetobacter baumannii. Oxacillin resistance was detected in 64.9% of the S.aureus isolates. The oxacillin resistance as a rule was associated with resistance to macrolides, aminoglycosides and fluoroquinolones. As for coagulase negative staphylococci, oxacillin resistance was stated in 75.6% of the isolates. All the isolates of the Staphylococcus spp. preserved their susceptibility to vancomycin and linezolid.

[Microbial view and optimal antibiotic therapy in acute purulent ENT diseases]. / Mikrobnyi peizazh i puti ratsional'noi antibiotikoterapii pri ostrykh gnoinykh zabolevaniiakh LOR-organov.

The aim of the study was elaboration of optimal antibiotic treatment in acute pyoinflammatory ENT pathology basing on the results of updated microbial tests and basic rules of microflora suppression by antibiotics. A total of 200 patients were examined. Of them, acute purulent sinusitis was diagnosed in 15, acute purulent otitis media in 25, paratonsillar abscess in 12 cases. Their microflora was studied for antibiotic sensitivity, the ability to form beta-lactamase was evaluated, microbiological examination of the content from purulent foci was made. It was found that the majority of acute purulent ENT diseases were caused by streptococci, gram-negative microorganisms (H. influenzae, M. catarrhalis, Klebsiella spp. et al), staphylococci and obligate anaerobes most of which produce beta-lactamase (up to 79%). From 88 to 100% pathogens were sensitive to amoxicillin/clavulanate, 18-59% -- to cephasoline, lincomycin or ampicillin. The treatment with antibiotics of different groups was assessed by dynamics of clinical symptoms and results of repeated microbiological analyses. The optimal antibiotic to start therapy of patients with acute purulent ENT diseases was amoxicillin/clavulanate in a new form -- 1000 mg (twice a day for 7 days).

[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.

[Microbiological monitoring for the causative agents of nosocomial infections (exemplified by resuscitation and intensive therapy units)]. / Mikrobiologicheskii monitoring za vozbuditeliami nozokomial'nykh infektsii (na primere otdelenii reanimatsii i intensivnoi terapii).

More than 900 isolates from at least 1500 patients were tested within 1996-1998. Gram-negative organisms were the main pathogens isolated from patients with different forms of nosocomial complications such as late pneumonia, associated with artificial ventilation of the lungs, and various secondary wound or urinary tract infections. The prevalence of Pseudomonas aeruginosa was stated. Antibioticograms showed that the most active drugs were imipenem (more than 90 per cent of the susceptible isolates) and ticarcillin/clavulanate (48-58 per cent of the susceptible isolates). The activity of ticarcillin/clavulanate (Timentin) was practically the same as that of imipenem against 21 strains of P.aeruginosa isolated from the blood and cerebrospinal fluid of 21 patients with sepsis and 3 patients with secondary purulent meningitis.

[A trial of using timentin (ticarcillin/clavulanate) in treating abdominal surgical infection]. / Opyt primeneniia timentina (tikartsillin/klavulanata) v lechenii abdominal'noi khirurgicheskoi infektsii.

Efficacy of timentin was studied in the treatment of 19 patients with peritonitis of various etiology and clinical and laboratory signs of systemic inflammatory reaction characteristic of abdominal sepsis. The clinical and bacteriological effects were recorded in 84.2 and 87.5 per cent of the cases respectively. The drug was administered intravenously dropwise for 30 minutes in a dose of 3.1 g every 4 hours. The treatment course was 4-11 days. The treatment failed in 3 patients. One of them had general peritonitis of gynecological etiology. In the other no significant regression of abdominal sepsis was observed, Pseudomonas aeruginosa strains were isolated from the abdominal cavity, the antibiotic was changed, still incurable polyorganic insufficiency developed and the patient died. The third patient had perforation of the large intestine due to tumor. No adverse reactions to the use of timentin in any of the cases was observed.

[The results of a multicenter study of the comparative activity of cefepime and other antibiotics against the causative agents of severe hospital infections (the Micromax program)]. / Rezul'taty mnogotsentrovogo issledovaniia sravnitel'noi aktivnosti tsefepima i drugikh antibiotikov v otnoshenii vozbuditelei tiazhelykh gospital'nykh infektsii (programma "Micromax").

A multicentre trial was performed on the activity of cefepime in comparison with ceftazidime, ceftriaxone, piperacillin/tazobactam, imipenem and ciprofloxacin against severe hospital infection pathogens in intensive care units. The isolates of Escherichia coli and Proteus spp. from the majority of the centres were highly susceptible to the antibiotics (90 to 100 per cent of the isolates). In some centres up to 40 per cent of the isolates produced ESBL. The isolates of Klebsiella spp. were characterized by lower susceptibility, in some centres the frequency of the strains producing ESBL exceeded 90 per cent, by the MIC geometric mean cefepime was superior to the third generation cephalosporins, the frequency of resistance to ciprofloxacin ranged from 0 to 31 per cent, no resistance to imipenem was recorded. The frequency of resistance to the third generation cephalosporins and piperacillin/tazobactam in Enterobacter spp., Serratia spp., Citrobacter spp., Morganella spp., and Providencia spp. ranged from 10 to 52 per cent, the resistance to cefepime equaled 0-11 per cent, 0 to 17 per cent of the isolates were resistant to ciprofloxacin, some isolates were resistant to imipenem. As for the nonfermenting microorganisms their resistance to all the antibiotics tested was comparatively high and markedly differed in various centres. As a whole, 7 per cent of all the isolates of the nonfermenting organisms was resistant to cefepime, 10 per cent was resistant to imipenem, 17 per cent was resistant to ceftazidime, 21 per cent was resistant to piperacillin/tazobactam and 36 per cent was resistant to ciprofloxacin.

[The efficacy of cefepime (Maxipime) in the treatment of abdominal sepsis in surgical patients]. / Effektivnost' tsefepima (Maksipima) v lechenii abdominal'nogo sepsisa u khirurgicheskikh bol'nykh.

The efficacy of cefepime in the treatment of 46 patients operated for general peritonitis of various genesis and severity (APACHE II not greater than 35) was studied. Cefepime was used in a dose of 2 g administered every 12 hours as slow intravenous infusions in 0.9 per cent sodium chloride solution in combination with metronidazole administered intravenously in a dose of 7.5 mg/kg body weight. The treatment course was 4 to 15 days. 45 patients were given diflucan for the prophylaxis of fungal superinfection, 3 patients were given aminoglycoside antibiotics (netilmicin or amikacin) and 2 patients were given vancomycin per os. The favourable clinical effect of the cefepime therapy was stated in 38 patients (82.6 per cent) including 4 out of 10 patients with initial APACHE II > 15. 101 isolates of aerobic gram-negative and gram-positive microbes from 38 patients treated with cefepime in combination with metronidazole were tested to estimate the bacteriological efficacy of the therapy and it was shown that only 5.9 per cent of them was resistant. The pathogen eradication was stated in 84.2 per cent of the patients.

[The isolation amd study of lipopolysaccharide from Klebsiella pneumoniae vaccinal strain 204]. / Vydelenie i izuchenie lipopolisakharida Klebsiella pneumoniae vaktsinnogo shtamma 204.

K. pneumoniae lipopolysaccharide (LPS) was isolated from biomass grown under the conditions of controlled multicycle and continuous cultivation. A considerable yield of LPS containing the minimal amount of protein and nucleic acid admixtures was obtained from biomass grown by continuous cultivation with the concentration of glucose in the medium equal to 20 g/l and the content of dissolved oxygen at a level of 0% of complete saturation. Erythrocyte diagnosticum prepared on the basis of this LPS was found to have a sensitizing dose of 100 micrograms per ml of solid erythrocytic precipitate and high specificity, studied in the passive hemagglutination test with the use of rabbit sera.

[The effect of the processes of Klebsiella pneumoniae cultivation on the antigenic activity of vaccinal preparations for peroral use]. / Vliianie protsessov kul'tivirovaniia Klebsiella pneumoniae na antigennuiu aktivnost' vaktsinnykh preparatov dlia peroral'nogo primeneniia.

Whole-cell preparations, obtained from the microbial mass of K. pneumoniae grown by batch and continuous cultivation at a dilution rate of 0.24 and 0.41 hr-1 and used in animal experiments for oral administration, were shown to have different serological activity. The preparation obtained from biomass grown by continuous cultivation at a dilution rate of 0.41 hr-1 proved to be most active regarding the level of hemagglutinating antibodies to K. pneumoniae LPS. At the same time the 360-fold rise of the level of anti-LPS antibodies in rabbit immune sera was observed. On day 258 oral revaccination was made; after that the twofold rise of the level of anti-LPS antibodies in the sera of the animals was observed. These antibody levels exceeded 40-fold those registered before primary immunization, and sufficiently high antibody levels were retained for 4 more months (the term of observation).

[The biochemical and immunochemical characteristics of the protein preparations obtained by different methods from a biomass of Neisseria meningitidis serogroup B]. / Biokhimicheskaia i immunokhimicheskaia kharakteristika belkovykh preparatov, poluchennykh iz biomassy Neisseria meningitidis serogruppy B.

Protein preparations containing group B N. meningitidis outer membrane peptides of classes 1 (44-47 kD), 2 (40-42 kD) and 5 (26-30 kD) have been obtained from the biomass of group B N. meningitidis, grown in a fermenter in a synthetic medium under the conditions of controlled cultivation with regulated oxygen content and the intermittent drainage and filling of the fermenter and with the use of different extraction methods (lithium chloride extraction by the method of C. E. Frasch et al.; sodium deoxycholate and potassium thiocyanate extraction). The chemical composition of these preparations and their peptide content have been shown to depend on the method of extraction; the preparation containing the least amount of contaminating substances is obtained by extraction with potassium thiocyanate. High-molecular fractions of these protein preparations, studied by the method of immunoblotting, contain antigens cross-reacting with meningococcal sera, groups A and C.

[The effect of detergents on the immunological activity of the antigens of Neisseria meningitidis serogroup B[]. / Vliianie detergentov na immunologicheskuiu aktivnost' antigenov Neisseria meningitidis serogruppy B.

The complex study of the influence of detergents of different classes and aluminum hydroxide, a traditional adjuvant, on the immunological activity of individual N. meningitidis antigens (outer membrane proteins, polysaccharide B) and the complex preparation containing all these antigens revealed that changes in the antigenic and immunogenic properties of the antigens under study depended on the degree of their purification and the character of modifying substances. Aluminum hydroxide proved to be the most active adjuvant: it stimulated immune response to both outer membrane proteins and antigens of the protein-polysaccharide complex, while decreasing the antigenicity of outer membrane proteins and polysaccharide. Detergents increased the antigenicity of outer membrane proteins, both purified and, to a lesser extent, contained in the complex; still the immune response only to the purified preparation could be stimulated.

[The antibody response of animals to a corpuscular meningococcal group-B preparation with different methods of immunization]. / Antitel'nyi otvet zhivotnykh na korpuskuliarnyi meningokokkovyi serogruppy B preparat pri razlichnykh metodakh immunizatsii.

As revealed in animal experiments, the formation of antibodies to group-B N. meningitidis antigens (group-specific polysaccharide, lipopolysaccharide and outer membrane proteins) in response to administration of meningococcal corpuscular preparations depends on the method of administration, the dose, and the number of administrations. In the sera of rabbits, immunized orally, antibodies to all three antigens in sufficiently high titers have been detected.

[The reactogenicity and antigenic activity of a meningococcal group B vaccine made from a natural complex of the specific polysaccharide and outer membrane proteins]. / Reactogennost' i antigennaia aktivnost' vaktsiny meningokokkovoi gruppy B iz prirodnogo kompleksa spetsificheskogo polisakharida i belkov naruzhnoi membrany.

Group B meningococcal vaccine consisting of the natural complex of specific polysaccharide and outer membrane protein (OMP) has been shown to be moderately reactogenic, safe with respect to the effect of undermining tolerance to human brain tissue antigens and to produce no allergization of humans. The vaccine under study possesses antigenic activity: (a) immunization with this vaccine ensures the fourfold rise of the level of antibodies to the group-specific polysaccharide of group B meningococcus in about 80% of persons with the initially low level of antibodies, this percentage being retained during the whole period of observation, i. e. 85 days; (b) the vaccine enhances the level of antibodies to meningococcal OMP, determined in the enzyme immunoassay and the passive hemagglutination test; (c) these data are indicative of the expediency of immunizing the risk groups of persons with the initially low level of antibodies.

[The sorption of a protein-polysaccharide complex isolated from Neisseria meningitidis serogroup B on aluminum hydroxide gels and the immunological activity of the sorbed preparations]. / Sorbtsiia belkovo-polisakharidnogo kompleksa, vydelennogo iz Neisseria meningitidis serogruppy B, na geli gidroksida aliuminiia i immunologicheskaia aktivnost' sorbirovannykh preparatov.

The protein-polysaccharide complex, isolated from group B N. meningitidis, is a variant of vaccine for the prophylaxis of group B N. meningitidis infection. In this investigation the influence of the complex of the physical properties of aluminium hydroxide gels, the amount of gel, pH and the duration of sorption on the process of sorption has been studied. Aluminium hydroxide has been shown to produce a stimulating effect on the response of mice to the polysaccharide and protein contained in the complex after immunization made in two injections. Gels with a smaller particle size have been found to possess greater adjuvant activity, as well as greater absorbing activity. The immunological activity of the complex, adsorbed ex tempore, has proved to be no different from that of the complex adsorbed in an hour.