Carriage of streptococcus pyogenes in primary school children M protein types pyrogenic toxin genes and investigation of the clonal relationships between the isolates
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Dosyalar
Tarih
2015
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Mikrobiyoloji Bulteni
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
M-proteini ve pirojenik toksinler Streptococcus pyogenes’in en önemli virülans faktörleri olup, bu faktörler sırasıyla akut romatizmal ateş ve kızıl hastalığının patofi zyolojisinde önemli rol oynarlar. Bu çalış- mada, ilköğretim okulu çocuklarının farengeal S.pyogenes taşıyıcılık durumları, suşlar arasındaki klonal ilişki, izolatların M-protein tipleri ve pirojenik toksin gen varlığının araştırılması amaçlanmıştır. Çalışmaya, bölgemizdeki iki ilköğretim okulunda bulunan 668 çocuktan (yaş aralığı: 6-16 yıl) alınan boğaz kültürü örnekleri dahil edilmiştir. İzole edilen grup A streptokok suşları arasındaki klonal ilişki DiversiLab (BioMérieux, Fransa) yöntemiyle araştırılmış ve tespit edilen klonal ilişkiler PFGE (pulsed-fi eld gel electrophoresis) yöntemi ile doğrulanmıştır. İzolatların M-protein (emm) tiplemesi Centers for Disease Control and Prevention (CDC) tarafından önerilen DNA dizi analizi yöntemiyle gerçekleştirilmiştir. Pirojenik toksin kodlayan genlerden speA ve speC’nin varlığı in-house multipleks polimeraz zincir reaksiyonu (PCR) yöntemi ile araştırılmıştır. Çalışmada toplam 134 (%20.05) öğrencinin boğaz kültüründen S.pyogenes izole edilmiştir. 10 yaş ve üzeri öğrencilerin GAS taşıyıcılık oranı, 7-9 yaş grubu öğrencilerine göre istatistiksel olarak daha yüksek bulunmuştur (%22’ye karşı %16.4; p< 0.05). Dizi analizi ile bu izolatlardan 123’ünün M protein geni tiplendirilebilmiş ve 20 farklı emm tipi saptanmıştır. En sık tespit edilen emm tipi emm1 (n= 38, %30.9) olmuş, bunu sırasıyla emm12 (n= 18, %14.6), emm89 (n= 10, %8.1), emm118 (n= 8, %7.3) ve emm4 (n= 7, %5.7) izlemiştir. Toplam 25 (%18.6) izolatta pirojenik toksin geni bulunmuş; bunların 11’inde (%8.2) speA, 12’sinde speC (%8.9) ve ikisinde (%1.5) her iki gen birden saptanmıştır. DiversiLab yöntemi ile 134 S.pyogenes suşu içerisinde 62 farklı Rep (Repetitive extragenic palindromic)-PCR profi li belirlenmiştir. Klonal olarak ilişkili 36 izolat, 13 farklı küme içerisinde yer almıştır. Suşların kümeleşme oranı %26.9 olarak bulunmuş; aynı küme içerisinde yer alan izolatların tümü arasındaki klonal ilişki, PFGE yöntemi ile de doğrulanmıştır. Çalışmamızda, bölgemizdeki ilköğretim çocukları arasında GAS taşıyıcı- lığının yüksek olduğu ve M-protein tiplerine göre suşların 30 valanlı aşı tarafından kapsanma oranının %90’nın üzerinde olduğu tespit edilmiştir. İzolatların yaklaşık beşte birinde pirojenik toksin geni bulunması, taşıyıcılarda da kızıl hastalığı riskinin yüksek olabileceğini göstermiştir. Bununla birlikte, izolatlar arasında tespit edilen klonal ilişki oranı, okul içi GAS yayılımının risk oluşturabileceği lehine yorumlanmıştır.
M-protein and pyrogenic toxins are the most important virulence factors of Streptococcus pyogenes, and they play signifi cant role in the pathophysiology of acute rheumatoid fever and scarlet fever, respectively. In this study, the pharyngeal carriage of S.pyogenes of the primary school children, clonal relationship of the strains, M-protein types, and the presence of pyrogenic toxin genes were aimed to be investigated. A total of 668 throat cultures obtained from children (age range: 6-16 years) in two primary schools in our region, were included in the study. The clonal relationships of the isolated group A streptococci (GAS) strains were investigated by DiversiLab assay (BioMérieux, France), and the clonal relatedness was confi rmed by pulsed-fi eld gel electrophoresis (PFGE) method. M-protein (emm) typing was performed by DNA sequencing as suggested by Centers for Disease Control and Prevention (CDC). The genes encoding pyrogenic toxins, speA and speC, were investigated by an in-house multiplex polymerase chain reaction (PCR) method. S.pyogenes was isolated from 134 (20.05%) of the throat samples. The GAS carriage rate of the students aged ?10 was statistically higher than those 7-9 years age group (%22 vs %16.4, p< 0.05). The M protein gene could be characterized only among 123 isolates by DNA sequencing, and 20 different emm types were detected. The most frequent emm type was emm1 (n= 38, 30.9%) followed by emm12 (n= 18, 14.6%), emm89 (n= 10, 8.1%), emm118 (n= 9, 7.3%), and emm4 (n= 7, 5.7%). Pyrogenic toxin genes were found in 25 (18.6%) of the isolates, including speA in 11 isolates (8.2%) and speC in 12 isolates (8.9%) and both genes were detected in 2 isolates (1.5%). Sixty-two different Rep (Repetitive extragenic palindromic)-PCR profi les were detected in 134 S.pyogenes isolates by DiversiLab method. Thirteen different clusters were formed by a total of clonally related 36 isolates revealing a strain clustering ratio of 26.9%. Clonal relationship of all isolates in the same cluster was confi rmed by PFGE method. In this study, relatively high percentage of GAS carriage was observed among primary school children in our region. The coverage rate of the 30-valent vaccine was determined to be over 90% with respect to M-protein types. Since the pyrogenic toxin-encoding genes were found in one fi fth of the isolates from the studied subjects, we concluded that the carrier population may also have high risk for scarlet fever. We also concluded that, the clonal relationship ratio determined among the isolates may be a risk in school transmission of GAS.
M-protein and pyrogenic toxins are the most important virulence factors of Streptococcus pyogenes, and they play signifi cant role in the pathophysiology of acute rheumatoid fever and scarlet fever, respectively. In this study, the pharyngeal carriage of S.pyogenes of the primary school children, clonal relationship of the strains, M-protein types, and the presence of pyrogenic toxin genes were aimed to be investigated. A total of 668 throat cultures obtained from children (age range: 6-16 years) in two primary schools in our region, were included in the study. The clonal relationships of the isolated group A streptococci (GAS) strains were investigated by DiversiLab assay (BioMérieux, France), and the clonal relatedness was confi rmed by pulsed-fi eld gel electrophoresis (PFGE) method. M-protein (emm) typing was performed by DNA sequencing as suggested by Centers for Disease Control and Prevention (CDC). The genes encoding pyrogenic toxins, speA and speC, were investigated by an in-house multiplex polymerase chain reaction (PCR) method. S.pyogenes was isolated from 134 (20.05%) of the throat samples. The GAS carriage rate of the students aged ?10 was statistically higher than those 7-9 years age group (%22 vs %16.4, p< 0.05). The M protein gene could be characterized only among 123 isolates by DNA sequencing, and 20 different emm types were detected. The most frequent emm type was emm1 (n= 38, 30.9%) followed by emm12 (n= 18, 14.6%), emm89 (n= 10, 8.1%), emm118 (n= 9, 7.3%), and emm4 (n= 7, 5.7%). Pyrogenic toxin genes were found in 25 (18.6%) of the isolates, including speA in 11 isolates (8.2%) and speC in 12 isolates (8.9%) and both genes were detected in 2 isolates (1.5%). Sixty-two different Rep (Repetitive extragenic palindromic)-PCR profi les were detected in 134 S.pyogenes isolates by DiversiLab method. Thirteen different clusters were formed by a total of clonally related 36 isolates revealing a strain clustering ratio of 26.9%. Clonal relationship of all isolates in the same cluster was confi rmed by PFGE method. In this study, relatively high percentage of GAS carriage was observed among primary school children in our region. The coverage rate of the 30-valent vaccine was determined to be over 90% with respect to M-protein types. Since the pyrogenic toxin-encoding genes were found in one fi fth of the isolates from the studied subjects, we concluded that the carrier population may also have high risk for scarlet fever. We also concluded that, the clonal relationship ratio determined among the isolates may be a risk in school transmission of GAS.
Açıklama
Anahtar Kelimeler
Streptococcus pyogenes, Grup A streptokok, Emm tipi, Streptokokal pirojenik toksin, DNA parmak izi analizi, Streptococcus pyogenes, Group A streptococci, Emm type, Streptococcal pyrogenic toxin, DNA fi ngerprinting
Kaynak
Mikrobiyoloji Bulteni
WoS Q Değeri
Q4
Scopus Q Değeri
Cilt
49
Sayı
3
Künye
Otlu, B. Karakurt, C. Bayındır, Y. Kayabaş, Ü. Yakupoğulları, Y. Gözükara Bağ, H. (2015). Carriage of streptococcus pyogenes in primary school children M protein types pyrogenic toxin genes and investigation of the clonal relationships between the isolates. Mikrobiyoloji Bulteni, 49(3), 301–313.
