Macrolide Resistance and Its Molecular Genetic Mechanisms in Streptococcus pyogenes Isolated from Children.

The frequency and mechanisms of resistance to macrolides in Streptococcus.pyogenes isolated within 3 periods: 2011-2012 (246 strains), 2013-2014 (273 strains) and from January to November of 2015 (120 strains) were studied. The strains of S.pyogenes (639) were isolated from 17107 nasopharyngeal, vaginal and middle ear discharge smears of children on their visits to physiciants or hospitalization at somatic hospital departments. The susceptibility was tested by the disk diffusion method and E-test strips. Identification of the mechanisms of resistance to macrolides and lincosamides included phenotypic and molecular genetic methods. PCR was used to determine ermB and mef genes in 23 erythromycin resistant isolates. As compared to 2011-2012, resistance of S.pyogenes to macrolides increased from 5 to 16% in 2015 and that to clindamycin from 2 to 10%. Among 23 erythromycin resistant strains 6 (26.1%) belonged to the M phenotype, 3 (13.0%) belonged to the iMLS(b) phenotype and 14 (60.9%) belonged to the cMLS(b) pheno-type. The results of detecting the macrolide resistance genes in S.pyogenes showed that only 26.1% of the isolates expressed the mefA gene. The predominant share (65.2%) of the erythromycin resistant isolates possesed the ermB gene as a determinant and in 4.3% of the isolates the ermB gene was associatied with the mefgene. No resistance genes were detected 1 isolate. Therefore, the main mech- anism that determined resistance of S.pyogenes to macrolides was methylation of ribosomes mediated by the ermB gene.

[Serotype diversity and antimicrobial resistance of Streptococcus pneumoniae].

The pneumococcus (Streptococcus pneumoniae) is a common bacterial pathogen responsible for various infections, especially in children below 5 years of age. The severity of pneumococcal infections varies from self-limiting mucosal infections, including acute otitis media, sinusitis, and noninvasive pneumonia, to life-threatening invasive disease like bacteremia and meningitis. A high incidence of pneumococcal infections is combined with a constantly growing antibiotic resistance of this pathogen. The growing resistance is thought to be associated with misuse of antibiotics and emerging of resistant clones that may spread throughout the entire population. Pneumococcal polysaccharide conjugate vaccines (PCV) contain an assortment of pneumococcal capsular polysaccharides (from 7 to 13) that produce serotype-specific protective antibodies. Since early 2000's, the introduction of PCV into national immunization programs has been shown to substantially decrease the incidence of invasive pneumococcal disease and pneumococcal carriage associated with vaccine-type pneumococci in many countries. In 2014, PCV vaccination was included in the Russian national calendar of prophylactic vaccination. The present article reviews the current literature on serotype prevalence, antibiotic susceptibility, and PCV effect on the evolution of pneumococcus.

[Monitoring and antibiotic resistance profile of tracheal aspirate microbiota in ICU children with severe craniocerebral trauma].

Nosocomial infections and their rational antibiotic treatment represent a major challenge for the healthcare nowadays. In this context, gramnegative bacteria including Pseudomonas aeruginosa, Acinetobacter baumanii and Enterobacteriaceae spp. are etiologically important and characterized by a significant level of antibiotic resistance. To examine dynamics of the respiratory tract colonization by hospital flora, tracheal aspirates obtained at three time points from 69 children with severe craniocerebral trauma during their stay in ICU were analysed. Colonization was observed on the 4th day of the ICU stay with predomination of K. pneumoniae (45%) and A. baumanii (27-37%). P. aeruginosa was detected after the 8th day of the ICU stay with the isolation rate of 33%. Substantial proportions of P. aeruginosa (61%), A. baumanii (78%) and K. pneumoniae (25%) were resistant to carbapenems. In 65 carbapemen resistant isolates, the presence of carbapenemases was examined using PCRs. OXA-48 carbapenemase was detected in 11 out of 14 (78%) K. pneumoniae isolates. Among the A. baumanii isolates, 30/31 (97%) carried OXA-40 and 1/31 (3%) had OXA-23 carbapenemases. None of the examined A. baumanii and K. pneumoniae isolates produced metallo-betalactamases (MBL). In contrast, all 20 carbapenem resistant P. aeruginosa isolates produced a MBL, and in 12 out of 20 (60%) of theme VIM-2 was detected. Thus, gramnegative nosocomial microflora rapidly colonizes ICU patients and has a high level of resistance to antibiotics, including carbapenems.

[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.

[Etiology and rational therapy of severe otitis media purulenta acuta in children].

Etiology and antibiotic susceptibility of the pathogens of otitis media purulenta acuta in children was studied within 2000-2005. A total of 161 children at the age of 1 to 14 years were examined. The middle ear discharge collected during paracentosis (79.5%) or spontaneous perforation of the tympanic membrane (20.5%) was used in the bacteriological tests. The microflora growth in the culture was detected in 80% of the cases. The leading pathogen was Streptococcus pyogenes (47.5%), the part of Streptococcus pneumoniae amounted to 36.6% of all the etiologically significant microflora, the part of Staphylococcus aureus amounted to 6.9% and that of Haemophilus influenzae amounted to 4.0%. The part of the associations of 2 microorganisms equaled 5.0%. The species composion of the pathogens differed from that described in the literature. The isolates of S. pneumoniae and S. pyogenes were characterized by low resistance to macrolides (4.0-6.3%). As for the S. pneumoniae isolates, 97.3% of them was susceptible to penicillin. The results of the etiology study and the pathogen antibiotic susceptibility showed that the drugs of choice for the empirical antibacterial therapy of otitis media purulenta acuta in children should be amoxicillin and 1st generation cepholosporins. When the antibacterial therapy within the first 3 days fails, it is advisable to use protected aminopenicillins or 2nd generation cephalosporins. In case of the drug intolerance, macrolide antibiotics should be used.

[Evaluation of the influence of the bacterial vaccines Pneumo-23 and Act-HIB on the course of the chronic inflammatory process of the respiratory organs in children].

The effectiveness and safety of vaccination of children having chronic inflammatory lung diseses with Pneumo-23 and Act-HIB were evaluated. The group under study included 38 children having chronic pneumonia, congenital defects of lung development, Kartagener's syndrome, mucoviscidosis; of these children, 25 were vaccinated with Pneumo-23 and 13--with Act-HIB. For comparison a group of 40 children with the same pathology, but not vaccinated, was used. A favorable course of the postvaccinal period was noted. Prior to vaccination Streptococcus pneumoniae in association with Haemophilus influenzae were isolated from all patients; in a year after vaccination with Pneumo-23 these microorganisms were isolated only in monoculture: S. pneumoniae in 3 out of 25 cases (88% elimination) and H. influenzae in 10 out of 25 cases (60% elimination).

[Dynamics of Streptococcos pneumoniae antibiotic resistance extension in Moscow in 1998-2003]. / Dinamika rasprostraneniia antibiotikorezistentnosti sredi Streptococcus pneumoniae v Moskve v period s 1998 po 2003 gg.

During the 6-year observation period from 1998 to 2003 in Moscow there was recorded in 2000-2001 a decrease in the emergence of Streptococcos pneumoniae resistance to many antibacterials, while during the following years the respective index increased. The above dynamics in the resistance emergence was likely due to a decrease in the use of antibiotics in 1998-1999. In 2003 the rate of resistance to penicillin was 18.6%, 0.4 and 2.1% of the isolates were resistant to amoxicillin and cefotaxime respectively, the rate of resistance to erythromycin reached 19%, 65.4% of the resistant strains showed M phenotype. High rates of resistance were as well observed with respect to tetracycline (40.1%), co-trimoxazole (29.1%) and chloramphenicol (18.6%). Resistance to levofloxacin and moxifloxacin was detected only in rare strains.

[Moraxella catarrhalis in chronic and relapsing respiratory tract infections in children]. / Moxarella catarrhalis pri khronicheskikh i retsidiviruiushchikh zabolevaniiakh organov dykhaniia u detei.

Examination of 700 children with chronic and relapsing respiratory tract infections showed that during the period from 1996 to 2003 Moraxella catarrhalis strains were isolated from the sputum of 5.5-9.7% of the patients. The frequency of the emergence was the third after Haemophilus influenzae and Streptococcus pneumoniae. In healthy children M. catarrhalis was isolated in 2.7% of the cases. The most frequent detection of M. catarrhalis was stated in children under 1 year (4.5%). The antibiotic susceptibility tests revealed that the majority of the M. catarrhalis isolates had beta-lactamase activity, were resistant to benzylpenicillin, ampicillin and lincomycin and highly susceptible to amoxycillin/clavulanate, macrolides, certain cephalosporins and levofloxacin. The isolates were most frequent in the patients of the rather severe contingent (congenital lung disease, alveolitis, chronic pneumonia, bronchial asthma). In such patients the bronchoobstructive syndrome was more frequent (46.6%). High frequency of the affection of the upper respiratory tracts in the examined children was stated (62.1%).

[Efficacy of levofloxacin (Tavanic) in the treatment of children with chronic pulmonary diseases]. / Effektivnost' levofloksatsina (Tavanik) pri khronicheskikh zabolevaniiakh legkikh u detei.

The efficacy of the fluoroquinolone levofloxacin in the treatment of 35 children with bronchopulmonary disease exacerbation was practically the same as that of amoxycillin/clavulanate, cefotaxime or ceftriaxone. The clinical and bacteriological results were favourable. The eradication of the pathogens responsible for the bronchopulmonary inflammations in 86% of the patients was stated. There is no doubt that fluoroquinolones should not be widely used in pediatrics. They should be considered as reserve drugs for the treatment of severe cases when the routine agents fail. Their use is justified when the situation is risky and the data on the pathogen susceptibility to the drugs are available. Still, levofloxacin is the most safe fluoroquinolone with low hepatotoxicity and lower effect on the central nervous system. The episodes of its negative cardiovascular action are less frequent. Moreover, the most frequent side effects of fluoroquinolones such as nausea, diarrhea or vomiting are less frequent with the use of levofloxacin. No signs of arthropathy in the patients treated with levofloxacin were observed in our trial.

[Resistance of urinary tract infection pathogens and choice of antibacterial therapy in pediatric urologic practice]. / Rezistentnost' vozbuditelei infektsii mochevoi sistemy i vybor antibakterial'noi terapii v detskoi urologicheskoi praktike.

The data on antibiotic resistance of the main uropathogens isolated from patients with urinary tract infection in an urologic department (319 isolates) and outpatient and diagnostic units (360 isolates) are presented. It was shown that by the antibiotic resistance the Escherichia coli isolates from the urologic department patients and outpatients did not practically differ: 44.1 and 47.8% of the isolates were resistant to ampicillin, 26.7 and 23.4% were resistant to amoxycillin/clavulanate, 28.9 and 24.9% were resistant to co-trimoxazole and 26.5% was resistance to cefuroxime (outpatients). The basic differences referred to Pseudomonas aeruginosa: resistance to ceftazidime in 38.5% of the isolates and resistance to gentamicin in 36.2% of the isolates. The activity against P. aeruginosa could be arranged as follows in the decreasing order: amikacin = meropenem > imipenem > cefepime = cefoperazone/sulbactam > gentamicin = ceftazidime. Resistance of P. aeruginosa to fluoroquinolones (ciprofloxacin and levofloxacin) remained low (7.4 and 8.0% respectively). No ampicillin resistance was revealed in the isolates of Enterococcus faecalis.

[Haemophilus influenzae antibiotic resistant strains isolated in Moscow in 2002-2004]. / Antibiotikorezistentnost' shtammov Haemophilis influenzae, vydelennikh v Moskve s 2002 po 2004.

The results of 3-year observation on emergence of H. influenzae antibiotic resistant strains in Moscow are summarized. The study included 566 strains isolated from patients in 2002-2004. The susceptibility was determined by the 2-fold microdilution method on the Haemophilus test medium. The percentage of the resistant strains isolated in 2002, 2003 and 2004 was the following: ampicillin --4.9, 3.2 and 3.6%, tetracycline--3.3, 3.2 and 1.8% and co-trimoxazole--10.9, 20.9 and 20% respectively. The strains isolated in 2003 and 2004 were resistant to azithromycin in 0.6 and 1.8% of the isolates and to clarithromycin in 1.3 and 3.2% of the isolates respectively. Five isolates differed by the minimum resistance to ampicillin whereas producing no beta-lactamase (BLNAR strains). The drugs of choice for the treatment of respiratory tract infections mainly due to H. influenzae, i.e. acute otitis and sinusitis, chronic bronchitis exacerbation and sometimes pneumonia remain betalactam antibiotics. From the microbiological viewpoint the inhibitor-protected aminopenicillins, cefuroxime and cefotaxime have no significant advantages vs. amoxycillin. The use of cotrimoxazole and chloramphenicol should be considered inexpedient.

[Autoantibodies in children with chronic inflammatory lung diseases]. / Autoantitela u detei s khronicheskimi vospalitel'nymi zabolevaniiami legkikh.

124 sera of children with chronic bronchitis, chronic pneumonia, bronchial asthma, exogenic allergic alveolitis, congenital developmental defects of the lungs and the syndrome of the situs inversus of organs were examined with a view to study the state of humoral immunity to tissues. The study was carried out by means of the enzyme-linked immunosorbent assay with the use of collagen, elastin, DNA (native and denaturated), membrane antigens of the lung, the liver, the small intestine and the large intestine. Among all groups of patients autoimmune disturbances, manifested by a rise in the level of autoantibodies of different specificity, were registered. The degree of manifestation of autoimmune disturbances depended on the kind of pathology. After treatment a decrease in the level of autoantibodies was registered in the examinees.

[Antibiotics in bacterial acute respiratory tract infection in children]. / Antibiotiki pri bakterial'nykh ORZ u detei.

The data on changes in the susceptibility of the most frequent respiratory tract pathogens i.e. Pneumococcus spp. and Haemophilus influenzae within the last 15 years and Streptococcus spp., Staphylococcus spp. and Moraxella spp. at the present time as well as recommendations based on the original and some literature data on the choice of the antibacterial drugs for the initial treatment of bacterial complications of acute respiratory tract viral infections such as otitis, sinusitis and pharyngitis are presented. The necessity of decreasing the unjustified use of antibiotics in cases of uncomplicated acute respiratory tract viral infections is indicated.

[Etiology and treatment of pneumonia in children]. / Etiologiia i lechenie pnevmonii u detei.

The most widespread pathogens of pneumonia in children i.e. Streptococcus pneumoniae and Haemophilus influenzae and their antibiotic susceptibility are described. The ways of selecting starting antibacterial drugs for the treatment of community-acquired and hospital pneumonia are recommended proceeding from the original findings and some literature data. Oral drugs for the treatment of uncomplicated pneumonia are shown to be preferential. In the treatment of nosocomial or hospital pneumonia the starting regimen should allow for the previous antibacterial therapy.

[Clinical significance of fungal and microbial associations and antibacterial therapy for treatment of chronic inflammatory respiratory tract diseases in children]. / Klinicheskoe znachenie gribkovo-mikrobnykh assotsiatsii i antibakterial'naia terapiia pri khronicheskikh vospalitel'nykh zabolevaniiakh organov dykhaniia u detei.

Microbiological examination applied to 270 children with chronic inflammatory and relapsing respiratory tract diseases revealed that by the frequency of the etiologically significant organisms the main pathogens isolated from the bronchial secretion belonged to Haemophilus influenzae, then followed Streptococcus pneumoniae and the less frequent isolates belonged to Branhamella catarrhalis characterized by high susceptibility to the 2nd and 3rd generation cephalosporins, erythromycin and azithromycin. Mycological investigation of the oral mucus and sputum from the patients revealed high frequency of Candida, mainly C.albicans. The fungi were most frequent and abundant in the children with chronic pulmonary diseases and congenital immune deficiency and in the children with bronchial asthma and asthmatic bronchitis, as well as in the children with exacerbation of the chronic disease, especially with bronchial obstruction. The antibacterial therapy with semisynthetic penicillins, cephalosporins and macrolides led to an increase in the number of the Candida carriers and in the biological material contamination level. The fungal contamination of the host was mainly observed after the use of the penicillins and cephalosporins. Chronic Candida carriers were detected among the patients with chronic inflammatory diseases of the lungs. The diseases in such patients were particularly severe. There were also detected children with colonization resistance to Candida. In the latter cases the chronic process was more favourable. The data made it possible to recommend a more differential use of the antibacterial and antimycotic drugs in the treatment of children with chronic inflammatory diseases of the bronchopulmonary system.

[Antibioticograms of microorganisms isolated from foci of local infections in infants]. / Antibiotikogrammy mikroorganizmov, vydelennykh iz ochagov lokal'nykh infektsii u novorozhdennykh detei.

Microbiological tests were performed in regard to 474 newborns within 1985-1995. It was shown that gram-positive microflora (Staphylococcus epidermidis and Staphylococcus aureus) predominated in the etiological structure of omphalitis and conjunctivitis. Among gram-negative isolates in the cases with omphalitis there predominated Klebsiella pneumonia. The antibioticograms were of great practical value for the adequate therapy.

[The features of Haemophilus influenza and Streptococcus pneumoniae carriage and the comparative characteristics of strains isolated from healthy children and from patients with acute and chronic respiratory infections]. / Osobennosti nositel'stva Haemophilus influenzae i Streptococcus pneumoniae i sravnitel'naia kharakteristika shtammov, vydelennykh ot zdorovykh detei i bol'nykh ostrymi i khronicheskimi respiratornymi infektsiiami.

The biological properties (serotypes, biotypes and adhesive activity) of 839 H.influenzae strains isolated from healthy children and from patients with acute and chronic respiratory infections, as well as the serotype composition of 739 S.pneumoniae isolated from the same groups of children, were studied. The occurrence of H.influenzae carriership among healthy children varied between 13% and 78%, decreasing among older children. In 98% of cases the respiratory tract of healthy children was colonized by noncapsular forms of H.influenzae. The isolation frequency of pneumococci in healthy children was 16%, but during the period of 2 years 45% of children were found to be the transitory carriers of this infective agent. The persistence of H.influenzae and S.pneumoniae with the same biological properties lasted for 1-4 months. Repeated infections were caused, as a rule, by bacteria with other properties. S.pneumoniae persisting in healthy children and causing a chronic bronchopulmonary process had no differences in their serological composition (19, 6, 3). At the same time in acute pneumonia, complicated by pleuritis and pneumonia destruction, pneumococci of serotypes 1, 3, 5 and 14 were more frequently isolated. H.influenzae isolated from healthy children and from patients with chronic pneumonia had little difference in the occurrence of their capsular variants, but in the biotype composition of H.influenzae isolated from chronic pneumonia patients biotype 1 occurred more frequently.

[Use of oral macrolide and azalide antibiotics in children with bronchopulmonary diseases]. / Primenenie peroral'nykh makrolidnykh i azalidnykh antibiotikov pri bronkholegochnoi patologii u detei.

The therapeutic efficacy of oral macrolides (erythromycin base and midekamycin, macropen) and azalides (azithromycin, sumamed) in the treatment of children with acute and chronic (during the aggravation) bronchopulmonary diseases was studied. The main etiological factors of acute and chronic pneumonia were Streptococcus pneumoniae and Haemophilus influenzae. The proportion of Staphylococcus aureus was high in infants with acute pleuropulmonary inflammations. The susceptibility of the isolates to the antibiotics was found to be high. The results of the trials showed that erythromycin, macropen and azithromycin were efficient in the treatment of acute and chronic pneumonia. The foci of acute pneumonia dissolved after oral administration of the drugs within the same periods as after the use of other parenteral antibiotics. The comparative estimation of the drug efficacy revealed that azithromycin was more active. The ease of the azithromycin administration (in the form of a suspension) in infants and children once a day for a shorter treatment course up to 5 days, high efficacy and no adverse reactions permitted to consider the antibiotic as the most promising antibacterial agent for the treatment of respiratory infections in children in hospitals and outpatient departments.