Class 1 and class 2 integrons and plasmid-mediated antibiotic resistance in coliforms isolated from ten rivers in northern Turkey

Abstract

We aimed to determine the molecular mechanisms of antibiotic resistance in coliforms isolated from ten rivers in northern region of Turkey. A total of 183 isolates were tested for antimicrobial susceptibility by disk diffusion and agar dilution methods. Resistance to ampicillin, streptomycin, trimethoprim, tetracycline, and chloramphenicol was detected in 58%, 51.9%, 24%, 28.4%, and 12.5%, respectively. Twelve (6.5%) phylogenetically distant organisms were detected to harbor self-transmissible plasmids ranging 52 to >147 kb in sizes. Resistances to ampicillin, tetracycline, trimethoprim, streptomycin, and nalidixic acid were commonly transferable traits. Transferable nalidixic acid-resistant strains harbored qnrS gene, which was the first report of plasmid-mediated quinolone resistance in bacteria of environmental origin in Turkey. Fourteen and five coliforms harbored class 1 and class 2 integrons, respectively, and some of them were located on transferable plasmids. Sequence analyses of variable regions of the class 1 and 2 integrons harbored various gene cassettes, dfrA1, dfr2d, dfrA7, dfrA16, dfrA17, aadA1, aadA5, bla(oxA-30), and sat1. A gene cassette array, dfrA16 has been demonstrated for the first time in a Citrobacter koseri isolate. Class 1 and class 2-bearing strains were clustered in different groups by BOX-PCR fingerprinting. Rivers in the northern Turkey may act as receptacle for the multi-drug resistant enterobacteria and can serve as reservoirs of the antimicrobial resistance determinants in the environment. The actual risk to public health is the transfer of resistance genes from the environmental bacteria to human pathogens.

Role of integrons in antimicrobial resistance: A review

“…In another study conducted on 322 E. coli strains previously isolated from irrigation water and associated sediments at the El Paso, Presidio, and Weslaco regions of the river, only one isolate was detected to contain class 2 integron (Matthew, 2003). In an investigation on antibiotic resistance mechanism in 183 coliforms isolated from ten rivers in northern region of Turkey, 2.7% (5/183) of the coliforms harbored class 1 and class 2 integrons, respectively (Ozgumus et al, 2009). As K. pneumoniae was concerned, the occurrence was low.…”

Antimicrobial Susceptibility of Escherichia coli Strains Collected from the Southwestern Coast of Istanbul

“…Ozgumus et al, examined seawater based coliforms class 1 and class 2 integron gene tapes and antibiotic resistance characteristics. The study found that ampicillin resistant E.coli contained the TEM-1 type β-lactamase gene 20 . Also, they found that among the tetracycline resistant strains, the tet (B) gene was common.…”

İşlenme Aşamalarındaki Çay Yapraklarından izole Edilen Koliform Grubu Bakterilerde Antibiyotik Direnç Profilinin Araştırılması

“…Ampisiline karşı yüksek bir (% 81,73) direnç tespit edilmiş ve seftazidim de direnç oranı olarak (% 13,5) ikinci sırada yer almıştır. Yapı-lan birçok çalışma klinikte oldukça sıklıkla kullanılan beta-laktam antibiyotiklerine karşı yüksek oranda direncin birçok çevreden izole edilen enterik bakterilerde bulunduğunu göstermiştir [19,20,21,22]. Bu grup antibiyotiklere karşı oluşan direnç genellikle transfer edilebilir direnç plazmitleri (R-plazmit) üzerinde bulunmakta ve bu da direncin aynı tür veya farklı tür mikroorganizmalar arasında hızlıca yayı-lımına sebep olmaktadır [23].…”