Publication: Kronik akciğer hastalığı olan, akut alevlenme ve pnömoni tanısı ile başvuran çocuklarda streptococcus pneumoniae serotip dağılımı ve antimikrobiyal duyarlılıkları
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2013
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Bu çalışmada, 2008-2010 tarihleri arasında hastanemize akut alevlenme ile başvuran, kronik akciğer hastalığı olan çocuk hastaların solunum yolu örneklerinden izole edilen Streptococcus pneumoniae kökenlerinin serotip dağılımı ve antibiyotik dirençlerinin araştırılması amaçlanmıştır. Hastaların solunum yolu örneklerinden izole edilen 61 S.pneumoniae kökeninin, penisilin ve seftriakson duyarlılıkları E-test (AB Biodisk, İsveç) yöntemiyle, eritromisin, klindamisin, tetrasiklin, trimetoprim-sülfametoksazol (TMP-SMZ), vankomisin ve levofloksasin duyarlılıkları ise disk difüzyon yöntemiyle çalışılmış ve CLSI önerileri doğrultusunda değerlendirilmiştir. Makrolid direnç fenotiplerini belirlemek üzere eritromisin-klindamisin çift disk testi kullanılmıştır. Makrolid direnç genlerinin [ermB, mef(A)/(E), ermTR] varlığı özgül primerler kullanılarak polimeraz zincir reaksiyonu (PCR) ile saptanmıştır. S.pneumoniae kökenlerinin serotiplendirmeleri multipleks PCR yöntemi ile 40 farklı serotipe özgül primerler kullanılarak araştırılmıştır. CLSI’nın oral penisilin için belirlediği kriterlere göre kökenlerin sadece %8.2 (5/61)’sinde penisilin direnci saptanırken, orta düzeyde direnç izolatların %54 (33/61)’ünde saptanmış, parenteral penisilin için ise bu oran %1.6 (1/61) olarak bulunmuştur. Eritromisin, klindamisin, tetrasiklin ve TMP-SMZ direnç oranları sırasıyla %55.8, %46, %47.5 ve %67.2 olarak bulunmuş, vankomisin ve levofloksasin direnci saptanmamıştır. Makrolide dirençli kökenlerin %82.4 (n= 28)’ünde yapısal makrolid-linkosamid-streptogramin B (cMLSB); %17.6 (n= 6)’sında M fenotipi gözlemlenmiş, indüklenebilir MLSB (iMLSB) fenotipine ise rastlanmamıştır. Makrolid direnç genlerinden ermB geni izolatların %50’sinde ve mef(A)/(E) geni %14.7’sinde tek başlarına bulunurken, izolatların %35.3’ünde ermB + mef(A)/(E) genlerinin beraber bulunduğu saptanmıştır. ermTR geni ise izolatların hiçbirinde tespit edilmemiştir. En sık izole edilen serotipler 19F, 23F ve 6 olup, bu serotiplerdeki penisilin (sırasıyla %34, %15.7 ve %18.4) ve makrolid (sırasıyla %38.2, %20.6 ve %14.7) direnç oranlarının oldukça yüksek olduğu belirlenmiştir. 7-, 10- ve 13-değerli konjuge pnömokok aşısı ve 23-değerli pnömokok aşısının serotip kapsama oranları sırasıyla %65, %67, %69 ve %78.6 olarak tespit edilmiştir. Bu kapsama oranları ile yoğun antibiyotik kullanımına maruz kalan kronik akciğer hastalığı olan çocuklarda ülkemizde kullanılan aşıların etkin olacağı gözlemlenmiştir.
This study aimed to investigate serotype distribution and antimicrobial resistance of Streptococcus pneumoniae isolates obtained from children with chronic respiratory diseases admitted to hospital with a diagnosis of acute exacerbations between 2008-2010 at Marmara University Hospital, Istanbul, Turkey. Sixty one S.pneumoniae strains isolated from the respiratory samples of patients were studied for erythromycin, clindamycin, tetracyline, trimethoprim-sulphametoxazole (TMP-SMX), vancomycin, levofloxacin susceptibilities by disk diffusion method; MIC values of penicillin and ceftriaxone were determined by E-test (AB Biodisk, Sweden). Results were evaluated according to the CLSI standards. The erythromycin-clindamycin double disc method was applied for the detection of macrolide resistance phenotypes. The presence of macrolide resistance genes, ermB, mef(A)/(E), ermTR were determined by PCR using spe- cific primers for each gene. The serotypes were determined by multiplex PCR using specific primers for 40 different serotypes. According to CLSI criteria, penicillin resistance in S.pneumoniae isolates were found to be 8.2% (5/61) and intermediate resistance rate was 54% (33/61) for oral penicillin. Penicillin resistance were found to be only 1.6% (1/61) for parenteral penicillin. Resistance rates of erythromycin, clindamycin, tetracyline, TMP-SMX were detected as 55.8%, 46%, 47.5% and 67.2%; respectively. No resistance was detected to vancomycin and levofloxacin. Constitutive macrolide-lincosamide-streptogramin B (cMLSB) phenotype and M phenotype were observed in 82.4% (n= 28) and 17.6% (n= 6) of the macrolide resistant isolates, respectively. Inducible macrolide-lincosamide-streptogramin B (iMLSB) phenotype was not detected. The macrolid resistance genotypes, ermB, mef(A)/(E), were positive 50% and 14.7%; respectively. Both ermB and mef(A)/(E) genes were detected 35.3% of the macrolid resistant isolates. None of the isolates were positive for ermTR gene. The most common S.pneumoniae serotypes were determined as serotype 19F, 23F and 6, furthermore penicillin (34%, 15.7% and 18.4%, respectively) and macrolide (38.2%, 20.6% and 14.7%, respectively) resistance rates of those serotypes were found relatively high. Serotype covarage of 7-, 10-, 13-valent conjugated pneumococcal vaccines and 23- valent pneumococcal vaccine were 65%, 67%, 69%, and 78.6%, respectively. In our country, use of the vaccines with these coverage rates has been observed to be effective in children exposed to intensive use of antibiotics with chronic lung disease.
This study aimed to investigate serotype distribution and antimicrobial resistance of Streptococcus pneumoniae isolates obtained from children with chronic respiratory diseases admitted to hospital with a diagnosis of acute exacerbations between 2008-2010 at Marmara University Hospital, Istanbul, Turkey. Sixty one S.pneumoniae strains isolated from the respiratory samples of patients were studied for erythromycin, clindamycin, tetracyline, trimethoprim-sulphametoxazole (TMP-SMX), vancomycin, levofloxacin susceptibilities by disk diffusion method; MIC values of penicillin and ceftriaxone were determined by E-test (AB Biodisk, Sweden). Results were evaluated according to the CLSI standards. The erythromycin-clindamycin double disc method was applied for the detection of macrolide resistance phenotypes. The presence of macrolide resistance genes, ermB, mef(A)/(E), ermTR were determined by PCR using spe- cific primers for each gene. The serotypes were determined by multiplex PCR using specific primers for 40 different serotypes. According to CLSI criteria, penicillin resistance in S.pneumoniae isolates were found to be 8.2% (5/61) and intermediate resistance rate was 54% (33/61) for oral penicillin. Penicillin resistance were found to be only 1.6% (1/61) for parenteral penicillin. Resistance rates of erythromycin, clindamycin, tetracyline, TMP-SMX were detected as 55.8%, 46%, 47.5% and 67.2%; respectively. No resistance was detected to vancomycin and levofloxacin. Constitutive macrolide-lincosamide-streptogramin B (cMLSB) phenotype and M phenotype were observed in 82.4% (n= 28) and 17.6% (n= 6) of the macrolide resistant isolates, respectively. Inducible macrolide-lincosamide-streptogramin B (iMLSB) phenotype was not detected. The macrolid resistance genotypes, ermB, mef(A)/(E), were positive 50% and 14.7%; respectively. Both ermB and mef(A)/(E) genes were detected 35.3% of the macrolid resistant isolates. None of the isolates were positive for ermTR gene. The most common S.pneumoniae serotypes were determined as serotype 19F, 23F and 6, furthermore penicillin (34%, 15.7% and 18.4%, respectively) and macrolide (38.2%, 20.6% and 14.7%, respectively) resistance rates of those serotypes were found relatively high. Serotype covarage of 7-, 10-, 13-valent conjugated pneumococcal vaccines and 23- valent pneumococcal vaccine were 65%, 67%, 69%, and 78.6%, respectively. In our country, use of the vaccines with these coverage rates has been observed to be effective in children exposed to intensive use of antibiotics with chronic lung disease.
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Biyoloji, Biyoteknoloji ve Uygulamalı Mikrobiyoloji, Mikrobiyoloji