Investigation of beta lactamase genes and clonal relationship among the extended spectrum beta lactamase producing nosocomial escherichia coli isolates
Küçük Resim Yok
Tarih
2015
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Mikrobiyoloji Bulteni
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Genişlemiş spektrumlu beta-laktamaz (GSBL) üreten mikroorganizmalar günümüzde önemli bir sorun
oluşturmaktadır. Özellikle CTX-M beta-laktamazı üreten Escherichia coli, tüm dünyada yayılarak hem
nozokomiyal hem de toplumsal kaynaklı enfeksiyonlara neden olmaktadır. Bu çalışmanın amacı, GSBL
üreten hastane kökenli E.coli izolatlarında beta-laktamaz gen prevalansı, antibiyotik duyarlılıkları ve klonal
ilişkilerinin araştırılmasıdır. Çalışmaya, Haziran 2010-Haziran 2011 tarihleri arasında hastanede yatan hastaların
idrar (n= 26), kan (n= 25) ve yara (n= 25) örneklerinden izole edilen ve CDC kriterlerine göre hastane
enfeksiyonu etkeni olarak tanımlanan toplam 76 GSBL pozitif E.coli suşu dahil edilmiştir. İzolatların
antibiyotik duyarlılıkları, CLSI önerilerine göre Kirby-Bauer disk difüzyon yöntemiyle araştırılmıştır. GSBL
varlığı çift disk sinerji testi ile saptanmış, şüpheli olgularda sefotaksim/sefotaksim klavulanik asit E-test
şeriti (AB Biodisk, İsveç) kullanılmıştır. TEM, SHV, CTX-M, PER, VEB, GES, OXA-2 grup ve OXA-10 grup
beta-laktamaz genlerinin varlığı bu bölgelere özgül primerler kullanılarak polimeraz zincir reaksiyonu
(PCR) ile araştırılmıştır. Suşlar arasındaki klonal ilişkilerin tespiti için PFGE (pulsed-field gel electrophoresis)
yöntemi kullanılmıştır. GSBL üreten E.coli suşlarının en sık yoğun bakım (%35), dahiliye (%16) ve genel cerrahi (%13) bölümlerinden gönderilen örneklerden izole edildiği belirlenmiştir. Suşların tamamı
imipenem, meropenem ve amikasine duyarlı olarak saptanmış; tüm izolatların sefotaksim ve seftriaksona
dirençli olduğu izlenmiştir. Sefoksitin, ertapenem, sefoperazon/sulbaktam, piperasilin/tazobaktam, gentamisin,
siprofloksasin, sefepim, amoksisilin/klavulanik asit, aztreonam ve seftazidime duyarlılık oranları
ise sırasıyla; %96, %83, %63, %61, %50, %41, %25, %21, %20 ve %18’dir. Çalışmaya alınan E.coli
suşlarında CTX-M, TEM, OXA-2 grup, PER, SHV ve OXA-10 grup beta-laktamaz gen pozitifliği sırasıyla;
%89.5, %59.2, %15.8, %14.5, %11.8 ve %3.9 olarak bulunmuş; izolatların hiçbirinde GES ve VEB betalaktamaz
genine rastlanmamış; 1 (%1.3) izolatta ise araştırılan genlerden hiçbirisi saptanmamıştır. PCR
analizi sonucu, 25 izolatta TEM ve CTX-M genlerinin birlikte bulunduğu belirlenmiş; 20 izolatta yalnız
CTX-M ve iki izolatta yalnız TEM geninin varlığı tespit edilmiştir. SHV geni hiçbir izolatta tek başına
saptanmamıştır. PFGE yöntemi ile GSBL üreten izolatlar arasında belirgin bir klonal ilişki gözlenmemiştir.
Sonuç olarak bu çalışmada, hastanemizde nozokomiyal GSBL üreten E.coli suşları arasında CTX-M tipi
enzimin yüksek sıklıkta olduğu gösterilmiş; GSBL pozitif suşların poliklonal olarak yayıldığı belirlenmiş ve
baskın olan bir epidemik suş tanımlanamamıştır. Bununla birlikte, epidemik klonlar ile plazmidler arasındaki
ilişkiyi açıklayacak plazmid analizi ve multilokus dizi tiplendirme yöntemleri ile daha ileri çalışmalara
gereksinim olduğu düşünülmüştür.
Extended-spectrum beta-lactamase (ESBL) producing microorganisms currently cause a major problem. Among theseCTX-M beta-lactamase producing Escherichia coli has also disseminated worldwide as an important cause of both nosocomial and community-acquired infections. The aims of this study were to determine the prevalence of the beta-lactamase genes, antibiotic susceptibilities and clonal relationships of ESBL-producing nosocomial E.coli isolates. A total of 76 ESBL-producing E.coli strains isolated from urine (n= 26), blood (n= 25) and wound (n= 25) specimens of hospitalized patients identified as nosocomial infection agents according to the CDC criteria between June 2010-June 2011 were included in the study. Antibiotic susceptibilities of the isolates were detected by Kirby-Bauer disc diffusion method according to CLSI recommendations. ESBL production was tested by double disc diffusion method, and cefotaxime/cefotaxime-clavulanic acid E-test strips (AB Biodisk, Sweden) were used for indeterminate results. Presence of TEM, SHV, CTX-M, OXA-2 group, 0XA-10 group, PER, VEB and GES beta-lactamase genes were investigated by polymerase chain reaction (PCR) using specific primers. Pulsed-field gel electrophoresis (PFGE) method was used for the detection of clonal relationships among the strains. Most of the ESBL-producing E.coli strains were isolated from samples of inpatients in intensive care (35%), internal medicine (16%) and general surgery (13%) units. All of the 76 strains were found susceptible to imipenem, meropenem and amikacin; however all were resistant to cefotaxime and ceftriaxone. The susceptibility rates of the isolates to cefoxitin, ertapenem, cefoperazone/sulbactam, piperacillin-tazobactam, gentamicin, ciprofloxacin, cefepime, amoxicillin-clavulanic acid, aztreonam and ceftazidime were 96%, 83%, 63%, 61%, 50%, 41%, 25%, 21%, 20% and 18%, respectively. Among E.coli isolates, the frequency of CTX-M, TEM, OXA-2 group, PER, SHV and OXA-10 group beta-lactamase genes were found as 89.5%, 59.2%, 15.8%, 14.5%, 11.8% and 3.9%, respectively, while none of the isolates were positive for VEB and GES beta-lactamase genes. In 1 (1.3%) strain none of the investigated genes were detected. PCR analyses of the isolates revealed that 25 harbored CTX-M and TEM genes together, while 20 harbored only CTX-M and two harbored only TEM genes. Single SHV gene was not detected in any of the isolates. PFGE demonstrated no major clonal relationship between ESBL-producing isolates. This study indicated that CTX-M type enzymes were highly endemic among ESBL-producing nosocomial E.coli strains in our hospital, with the polyclonal spread of ESBL-producing bacteria without any dominant epidemic clone. In conclusion, it was considered that further studies are needed to explain the relationship between epidemic clones and plasmids with the use of plasmid analysis and multilocus sequence typing methods.
Extended-spectrum beta-lactamase (ESBL) producing microorganisms currently cause a major problem. Among theseCTX-M beta-lactamase producing Escherichia coli has also disseminated worldwide as an important cause of both nosocomial and community-acquired infections. The aims of this study were to determine the prevalence of the beta-lactamase genes, antibiotic susceptibilities and clonal relationships of ESBL-producing nosocomial E.coli isolates. A total of 76 ESBL-producing E.coli strains isolated from urine (n= 26), blood (n= 25) and wound (n= 25) specimens of hospitalized patients identified as nosocomial infection agents according to the CDC criteria between June 2010-June 2011 were included in the study. Antibiotic susceptibilities of the isolates were detected by Kirby-Bauer disc diffusion method according to CLSI recommendations. ESBL production was tested by double disc diffusion method, and cefotaxime/cefotaxime-clavulanic acid E-test strips (AB Biodisk, Sweden) were used for indeterminate results. Presence of TEM, SHV, CTX-M, OXA-2 group, 0XA-10 group, PER, VEB and GES beta-lactamase genes were investigated by polymerase chain reaction (PCR) using specific primers. Pulsed-field gel electrophoresis (PFGE) method was used for the detection of clonal relationships among the strains. Most of the ESBL-producing E.coli strains were isolated from samples of inpatients in intensive care (35%), internal medicine (16%) and general surgery (13%) units. All of the 76 strains were found susceptible to imipenem, meropenem and amikacin; however all were resistant to cefotaxime and ceftriaxone. The susceptibility rates of the isolates to cefoxitin, ertapenem, cefoperazone/sulbactam, piperacillin-tazobactam, gentamicin, ciprofloxacin, cefepime, amoxicillin-clavulanic acid, aztreonam and ceftazidime were 96%, 83%, 63%, 61%, 50%, 41%, 25%, 21%, 20% and 18%, respectively. Among E.coli isolates, the frequency of CTX-M, TEM, OXA-2 group, PER, SHV and OXA-10 group beta-lactamase genes were found as 89.5%, 59.2%, 15.8%, 14.5%, 11.8% and 3.9%, respectively, while none of the isolates were positive for VEB and GES beta-lactamase genes. In 1 (1.3%) strain none of the investigated genes were detected. PCR analyses of the isolates revealed that 25 harbored CTX-M and TEM genes together, while 20 harbored only CTX-M and two harbored only TEM genes. Single SHV gene was not detected in any of the isolates. PFGE demonstrated no major clonal relationship between ESBL-producing isolates. This study indicated that CTX-M type enzymes were highly endemic among ESBL-producing nosocomial E.coli strains in our hospital, with the polyclonal spread of ESBL-producing bacteria without any dominant epidemic clone. In conclusion, it was considered that further studies are needed to explain the relationship between epidemic clones and plasmids with the use of plasmid analysis and multilocus sequence typing methods.
Açıklama
Anahtar Kelimeler
Escherichia coli, Beta-laktamaz, CTX-M, Klonal ilişki, Beta-lactamase, Clonal relationship
Kaynak
Mikrobiyoloji Bulteni
WoS Q Değeri
Scopus Q Değeri
Cilt
49
Sayı
1
Künye
Görgeç, S. Kuzucu, Ç. Otlu, B. Yetkin, F. Ersoy, Y. (2015). Investigation of Beta Lactamase Genes and Clonal Relationship Among the Extended Spectrum Beta Lactamase Producing Nosocomial Escherichia coli Isolates. Mikrobiyoloji Bulteni, 49(1), 15–25.
