Characteristics of Stenotrophomonas maltophilia isolates from cystic fibrosis patients in Russia.

Stenotrophomonas maltophilia is a common opportunistic microorganism and an important respiratory pathogen in cystic fibrosis (CF). The aim of this study was to determine antimicrobial resistance phenotypes, sequence-types (ST) and genetic determinants of antibiotic resistance in S. maltophilia strains recovered from CF patients in Russia. S. maltophilia isolates recovered from 170 CF patients were analyzed. Minimum inhibitory concentrations of antibacterial agents were determined using Sensititre Gram Negative GNX2F plates and the results were interpreted according to Clinical and Laboratory Standards Institute (CLSI) criteria. Whole-genome sequencing (WGS) was performed on MGISEQ-2000 platform. SPAdes software, Galaxy, ResFinder, Integrall and PubMLST were used for analysis of WGS data. S. maltophilia strains were identified from 24/170 (14%) CF patients. In total, 25 isolates were detected, two strains were isolated from the same patient. The isolates belonged to 17 different STs, including 5 new STs; ST4 was the most prevalent ST. Resistance to ceftazidime was observed in 60% of strains, to ticarcillin-clavulanate - in 32%, to levofloxacin - in 24%, to trimethoprim/sulfamethoxazole - in 12% of strains. All isolates were susceptible to minocycline. All ST4 isolates were resistant or intermediate to ceftazidime and ticarcillin-clavulanate. In two isolates, the sul1 gene was detected. In one isolate, sul1 was part of a class 1 integron. The detected integron also contained the blaGES-7 and aac(6')-Ib-cr genes. The ST4 sequence-type was the most prevalent ST among S. maltophilia strains recovered from CF patients in Russia. Antibiotic resistance genes, including sul1, blaGES-7, aac(6')-Ib-cr, were detected in single strains.

Genome features and antibiotic resistance of Pseudomonas aeruginosa strains isolated in patients with cystic fibrosis in the Russian Federation.

Cystic fibrosis (CF) is a common genetic disease, manifested by airway obstruction and chronic respiratory infection. The most prevalent infectious agent in airways of CF patients is Pseudomonas aeruginosa. This study aimed to determine sequence-types, antimicrobial resistance phenotypes and genes defining adaptive antibiotic resistance in P. aeruginosa isolates recovered from CF patients in Russia. In total, 84 P. aeruginosa strains from 64 CF patients were analyzed. Susceptibility to antibiotics was determined by disk diffusion test. Whole-genome sequencing (WGS) was performed on MGISEQ-2000 platform. SPAdes software, Galaxy, ResFinder, PubMLST were used for analysis of WGS data. Examined P. aeruginosa isolates belonged to 53 different sequence-types (STs), including 6 new STs. High-risk epidemic clone ST235 (10%) and clonal CF P. aeruginosa strains ST17, ST242, ST274 (7%) were detected. Non-susceptibility to ticarcillin-clavulanate, cefepime, imipenem was observed in 63%, 12% and 25% of isolates, respectively; to tobramycin - in 24%, to amikacin - in 35%; to ciprofloxacin, levofloxacin - in 35% and 57% of strains, respectively. Multidrug-resistant phenotype was detected in 18% of isolates. In examined strains, genes of beta-lactamases VIM-2 (5 ST235 strains), VEB-1 (two ST2592 strains), GES-1 (1 ST235 strain), PER-1 (1 ST235 strain) were found. Ciprofloxacin-modifying enzyme CrpP gene was detected in 67% of isolates, aminoglycoside-modifying enzymes AAD, ANT, AAC genes - in 7%, 4%, 12% of strains, respectively. P. aeruginosa isolates from CF patients in Russia demonstrate a high clonal diversity, which is similar to other P. aeruginosa infections. The isolates of high-risk clone and clonal CF P. aeruginosa strains are detected.

Emergence of a ST307 clone carrying a novel insertion element MITEKpn1 in the mgrB gene among carbapenem-resistant Klebsiella pneumoniae from Moscow, Russia.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) represents a major nosocomial pathogen with only a few antimicrobial agents, including colistin, remaining active. However, the emergence of colistin-resistant (Col-R) isolates is compromising the activity of colistin. In this study, a collection of 159 CRKP recovered from three hospitals in Moscow (Russian Federation) was examined. The isolates demonstrated resistance to cephalosporins (100%), ciprofloxacin (92.5%), fosfomycin (90.1%), netilmicin (81.1%), gentamicin (84.3%) and amikacin (49.7%). The rate of colistin resistance (MIC > 2 mg/L by broth microdilution) was 44.7%; moreover, 6.7% of isolates were tigecycline-resistant. Among 18 sequence types (STs) discovered, isolates of five lineages including ST307 (n = 46; 28.9%), ST395 (n = 40; 25.2%), ST377 (n = 17; 10.7%), ST48 (n = 17; 10.7%) and ST23 (n = 16; 10.1%) dominated. Carriage of a blaOXA-48-like carbapenemase gene was detected in 146 CRKP (91.8%); 11 (6.9%) and 2 (1.3%) isolates harboured blaNDM-1 and blaKPC-3, respectively. Among 71 Col-R isolates, colistin MICs ranged from 4 mg/L to >1024 mg/L (MIC50/90, 2/512 mg/L). All Col-R isolates were mcr-1-negative. In 19 (26.8%) Col-R isolates, inactivation of mgrB by insertion sequences IS1A, IS1R, ISKpn14 and ISKpn26 and a novel miniature inverted-repeat transposable element (MITE) Kpn1 was observed. Carriage of MITEKpn1 was restricted to six ST307 isolates and affected mgrB at nucleotide position 75. mgrB deletion was observed in four (5.6%) Col-R isolates. Moreover, PmrA and/or PmrB were altered in three (4.5%) Col-R isolates with wild-type mgrB. Thus, blaOXA-48-like-carrying Col-R ST307 K. pneumoniae is emerging as a dominant clone in Moscow.

[The comparison of methods for determination of colistin susceptibility in carbapenem-resistant Klebsiella pneumoniae.]

In recent years, because of carbapenemase spreading in Klebsiella pneumoniae strains, the antibiotic of reserve group, colistin, is increasingly prescribed. In vitro testing of colistin susceptibility in everyday practice has a number of difficulties due to the cationic properties of molecule and weak diffusion into agar. Therefore it is recommended to use the reference Broth Microdilution Method (BMD) for determination of the Minimum Inhibitory Concentration (MIC) for colistin. The purpose of the study was to determine susceptibility to colistin in 119 carbapenem-resistant K. pneumoniae (CRKp) which were isolated from the patients at three hospitals in Moscow in 2012-2016 by the broth microdilution method (BMD) and to compare these data with the ones obtained by epsilometer test (E-test) and VITEK 2 Compact. The proportion of resistant isolates (MIC>2 mg/L) was 52%, 39%, 35% respectively. Both commercial methods demonstrated a high level of the very major error (VME) that was 26% for the E-test method and 34% for the VITEK 2 Compact. The values of categorical agreement and essential agreement (CA, EA) were less than 90%. A single major error (ME) was detected for the VITEK 2 Compact. In conclusion, results of both commercial tests for determination of MIC for colistin showed differences with the results of the reference BMD. It is necessary for clinical laboratories to be aware about this discrepancy and to use E-tests and VITEK 2 Compact with caution to determine colistin susceptibility.

[Burkholderia cepacia persistence in patients with mucoviscidosis].

AIM: Study features of persistence of Burkholderia cepacia in mucoviscidosis patients. MATERIALS AND METHODS: In the period from 2008 to 2009, 56 B. cepacia strains isolated from children with mucoviscidosis were obtained. 114 medical histories of children with mucoviscidosis from various age groups were analyzed. The developed algorithm for identification and typing including phenotype and molecular biology methods was used to identify B. cepacia bacteria. Strain genotyping was carried out by RAPD-PCR with random oligonucleotide primer as well as pulse-electrophoresis. RESULTS: Persistence of associations ofmicroogranisms in 59.4% of cases was established to be the feature of persistent infection in mucoviscidosis. The feature of persistence of B. cepacia strains in patients with diagnosis ofmuco-viscidosis mixed form, severe course is persistence in association with Pseudomonas aeruginosa. B. cepacia bacteria that can persist in mucoviscidosis patients are characterized by resistance to many antibiotics. A prolonged (up to 1 year and 5 months) persistence of B. cepacia strains isolated from 1 patient was proven by using microflora monitoring of lower respiratory tract. CONCLUSION: B. cepacia bacteria may colonize lower respiratory tract of mucoviscidosis patients, persist for a long time and be transmitted between patients.

[The detection of bacteriogenic causes of opportunistic infections].

In order to select bacteriocin producing strains the screening of microorganisms from clinical material was perfomed. The delayed antagonism method was used. 154 strains were screened, 93 (60%) cultures produced antagonistic substances. Micrococcus luteus NCTC, 2665, Candida albicans ATCC 885-653, Escherichihia coli 168/59, Pseudomonas aeruginosa 27/99, Klebsiella peumoniae 1954 were used as test-cultures, Pseudomonas aenruginosa and Staphylococcys aureus were the most frequent species producing antibacterial substances and their products were of high potency, with a wide spectrum of antimicrobial activity.

[Clinical and bacteriological efficacy and tolerability of meropenem in the treatment of bronchopulmonary affections in children with mucoviscidosis].

Meropenem (in combination with amikacin) was used in the treatment of children and adolescents with mucoviscidosis and severe exacerbation of bronchopulmonary affections. The drug showed satisfactory clinical and moderate bacteriological effects (48.3%) as dependent on the severity and duration of the disease and the microbial flora. Meropenem was well tolerated: no side effects were observed during the treatment, whereas it was used in high doses (60-105 mg/kg daily).

[Rational use of antibiotics in mucoviscidosis pediatric cases with an account of local microbiological monitoring].

The results of local microbiological monitoring of bronchial secretion in 482 children with mucoviscidosis observed within 2000-2004 in the Republican Centre of Mucoviscidosis are presented. The results provided development of recommendations for rational use of antibiotics in the treatment of infectious processes in pediatric patients with mucoviscidosis. Since the emergence of MRSA in such patients is low, it is recommended to use antistaphylococcal betalactams (oxacillin, cefazolin, amoxycillin/clavulanate) for the treatment of infections due to S. aureus. For the treatment of infections due to some other pathogens, except S. maltophilia, the most active betalactams were carbapenems (imipenem and meropenem). Ciprofloxacin was active against numerous etiological agents causing low respiratory tract infections in children with mucoviscidosis except S. maltophila and A. xylosoxidans subsp. xylosoxidans. For the treatment of infections due to P. aeruginosa, P. aeruginosa muc. and K. pneumoniae the most active aminoglycosides were amikacin and tobramycin (for P. aeruginosa and P. aeruginosa muc.), while gentamicin was not active in such cases. As for antibiotics of other groups, high activity against S. aureus in the treatment of children with mucoviscidosis was recarded with the use of vancomycin, fusidic acid and rifampicin. Azithromycin and co-trimoxazole were active against H. influenzae. Chloramphenicol was active against S. maltophilia, B. cepacia and H. influenzae in the treatment of such patients.

[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.

[Problems of prevalance and resistance of nosocomial Klebsiella pneumonia in hospitals of Russia].

Prevalence of Klebsiella pneumoniae among gramnegative pathogens of nosocomial infections in intensive care units of 33 hospitals of 22 towns in Russia was investigated. Antibiotic susceptibility and extended-spectrum beta-lactamase production were tested in 420 nosocomial K. pneumoniae isolates. Carbapenems (imipenem, meropenem and ertapenem) showed the highest activity. Extended-spectrum beta-lactamase production based on the phenotyping methods was revealed in 342 (81.4%) isolates. The maximum activity against the K. pneumoniae isolates producing extended-spectrum beta-lactamase was observed in imipenem and meropenem (no unsusceptible strains were isolated). 3.2% of the isolates was not susceptible to ertapenem. Differences in the activity of cefoperazone/sulbactam, amikacin, ciprofloxacin and levofloxacin against the extended-spectrum beta-lactamase producing isolates in various hospitals were recorded.

[Efficacy and safety of cefepime in the treatment of bronchopulmonary disease exacerbation in pediatric patients with mucoviscidosis].

Clinicobacteriological effect of cefepime (in combination with amikacin) was studies in 25 pediatric patients of the age of 7 to 17 years with a mixed form of mucoviscidosis at the stage of the bronchopulmonary infection exacerbation. The basic pathogens isolated from the sputum were: Pseudomonas aeruginosa sm., P. aeruginosa muc. (67.5%) and Staphylococcus aureus (29.1%). The 2-week treatment course resulted in a marked clinical effect with improvement of the lung functional indices and eradication of the majority of the S. aureus strains (81.2%) and half of the P. aeruginosa strains (49.6%). The only side effect was moderate diarrhea not requiring discontinuation of the drug use.

[Efficacy and safety of cefoperazone/sulbactam in the treatment of children with mucoviscidosis during exacerbation of the bronchopulmonary process]. / Effektivnost' i bezopasnost' tsefoperazona/sul'baktama pri lechenii obostrenii bronkholegochnogo protsessa u detei s mukovistsidozom.

The use of cefoperazone/sulbactam in combination with amikacin in the treatment of 20 patients with mucoviscidosis and exacerbation of bronchopulmonary pathological process resulted in marked positive dynamics of the clinical and functional indices of the lungs state. The bacteriological effect with respect to the main pathogens in the cases of mucoviscidosis was strain-dependent: eradication of 10 (83.4%) out of 12 Staphylococcus aureus strains and only 3 (15.8%) out of 19 Pseudomonas aeruginosa strains. The most frequent adverse reaction was diarrhea (5 children) successfully corrigated by loperamide. Discontinuation of the drug use was required in 3 patients because of macrohematuria (1 child) and allergic eruption.

[Pefloxacin in the treatment of patients with mucoviscidosis]. / Mesto pefloksatsina v lechenii bol'nykh mukovistsidozom.

It was shown that microbial flora isolated from the bronchial secretion of 39 patients with mucoviscidosis in 1999-2001 consisted in one third (32.8%) of S. aureus strains. Evaluation of pefloxacin efficacy in the case of monoinfection and pathogens association revealed potent antistaphylococcal effect of the drug. Positive result was demonstrated in 82.3% cases by the 7th day. Among the side effects dominated arthropathy which disappeared at the period from 3 days to 3 months after drug administration was stopped.

[Antibiotic therapy of cystic fibrosis in children]. / Antibiotikoterapiia pri muskovistsidoze u detei.

It is postulated that P. aeruginosa in monoculture or in association with Staphylococcus aureus keeps its leading position in chronic bacterial inflammatory broncho-pulmonary processes in children with cystic fibrosis. Antibiotic resistant strains of Burkholderia cepacia, Stenotrophomonas maltophila, Alcaligenes xylosoxidans were revealed (7.1% of the strains). P. aeruginosa strains were susceptible to aminoglycosides, ciprofloxacin, and polymixin B. Susceptibility of smooth and mucoid forms of P. aeruginosa to ceftazidime stayed at the level of 49.6-57.1%. Such microbial associations as P. aeruginosa sm. + S. aureus, P. aeruginosa sm. + P. aeruginosa muc. + S. aureus were mainly susceptible to ciprofloxacin, aminoglycosides and resistant to ceftasidime. Meropenem, cefepim and ciprofloxacin are highly effective antibiotics for the treatment of broncho-pulmonary processes exacerbations at children with chronic P. aeruginosa cystic fibrosis. Intravenous use of antibiotics out of hospital for the treatment of the children with cystic fibrosis is clinically effective, and is economically and psychologically reasonable. It should be used more widely in medical practice.

[Evaluation of tolerance and efficacy of pefloxacin in the treatment and prevention of severe infections in children with mucoviscidosis and aplastic anemia]. / Otsenka éffektivnosti i perenosimosti pefloksatsina pri lechenii i profilaktike tiazhelykh infektsii u detei s mukovistsidozom i aplasticheskoi anemiei.

Pefloxacin (Abaktal) efficacy and safety were investigated at 21 children (7-16 years old) randomized in 2 groups: children with mucoviscidosis and children with aplastic anemia. The drug was used at the dose 15-20 mg/kg per day bid for 14-28 days. Pefloxacin was used in combination with ceftazidime and amikacin. Combined therapy demonstrated good clinical efficacy. Bacteriological efficacy was not uniform: staphylococci were not isolated from sputum since the 7th day of treatment, but pseudomonads were cultured even on the 14th day of the treatment (the sensitivity to pefloxacin remained). The only but frequent side-effect was arthropathy. The background and some peculiarities of arthropathy development were analyzed. This phenomenon is called quinolone-induced synovitis. The risk group for quinolone-induced synovitis was estimated--children elder than 10 years with allergic anamnesis. Good clinical efficacy and tolerability of pefloxacin at the children with mucoviscidosis or aplastic anemia is a reason and base to cancel the limits to its use in pediatrics.

[The use of improved commercial micro-LA-tests for the identification of different groups of microorganisms in clinical microbiology]. / Ispol'zovanie usovershenstvovannykh kommercheskikh mikro-LA-testov dlia identifikatsii mikroorganizmov razlichnykh grupp v klinicheskoi mikrobiologii.

Lachema kits ENTEROtest 24, ENTERO-Rapid 24, ENTERO-Screen, NEFERMtest 24, STAPHYtest 16, STREPTOtest 16, En-COCCUS test were used in identification of 871 strains of microorganisms isolated from clinical material. The kits proved to be highly reliable: they identified 88.8-97.5% cultures and permitted rapid (within 4 h) identification of enterobacteria most often occurring in clinical practice. The advantages of these kits are stripped plates allowing identification of cultures in individual stripes, a wide spectrum of biochemical tests, modern composition of biosubstrates in suspension media, and rational disposition of the tests, allowing technologically simpler identification of a wider spectrum of cultures in one stage without difficult accessory tests. Comparison of the above kits with kits manufactured by bioMérieux (France) showed a 84.6-100% correlation of the results.

[The efficacy and safety of ciprofloxacin in treating children with mucoviscidosis]. / Effektivnost' i bezopasnost' tsiprofloksatsina pri lechenii detei s mukovistsidozom.

Ciprofloxacin clinical and bacteriological efficacies, as well as tolerability mainly with respect to chondrotoxicity were evaluated in the treatment of children with mucoviscidosis. The drug was shown to have high clinical and moderate bacteriological efficacies. As for its tolerability, adverse reactions chiefly associated with affection of the gastrointestinal tract, i.e. nausea, stomach pain, diarrhea, increased transaminase levels were recorded. The arthrotoxicity episode was single and transitory. The use of ciprofloxacin had no negative effect on the children growth. No chondrotoxic effect of ciprofloxacin in the treatment of children was observed which is explained in the paper. It is concluded that ciprofloxacin is in general an efficient and safe antibiotic useful for the treatment of children.

[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.