Plasmid Mediated Antibiotic and Heavy Metal Resistance in Bacillus Strains Isolated from Soils in Rize, Turkey

Abstract

Toprak örneklerinden izole edilen 15 adet Bacillus suşu 17 farklı antibiyotiğe (ampisilin, metisilin, eritromisin, norfloksasin, sefalotin, gentamisin, siprofloksasin, streptomisin, tobramisin, kloramfenikol, trimetoprimsulfametaksozol, tetrasiklin, vankomisin, oksasilin, neomisin, kanamisin ve novabiosin) ve 10 farklı ağır metale (bakır, kurşun, kobalt, krom, demir, cıva, çinko, nikel, manganez ve kadmiyum) karşı dirençliliği ve plazmit DNA içeriği bakımından incelenmiştir. Toplam olarak 11 suş (%67) en azından bir antibiyotiğe dirençli bulunmuştur. En yaygın direnç metisilin ve oksasilin’e karşı gözlemlenmiştir. En yaygın dirençli suşlar ise Bacillus sp. B3 ve Bacillus sp. B11 olarak tespit edilmiştir. Bakır, krom, çinko, demir ve nikel’e karşı direnç belirlenmesine rağmen, cıva direnci gösteren 3 suş hariç (B3, B11 ve B12) cıva ve kobalta karşı direnç belirlenmemiştir. Yedi adet Bacillus suşunun plazmit içerdiği tespit edilmiştir. İzole edilen plazmitler Bacillus subtilis W168 suşuna transforme edilmiş, ağır metal ve antibiyotik direnç belirleyicilerinin plazmit üzerinde taşındığı bulunmuştur. Bu sonuçlar hem antibiyotik hem de ağır metal direnci ile plazmit içeriği arasında bir ilişki olduğunu göstermektedir.

Fifteen Bacillus strains which were isolated from soil samples were examined for resistance to 17 different antibiotics (ampicillin, methicillin, erythromycin, norfloxacin, cephalotine, gentamycin, ciprofloxacin, streptomycin, tobramycin, chloramphenicol, trimethoprim-sulfamethoxazole, tetracycline, vancomycin, oxacilin, neomycin, kanamycin and, novabiocin) and to 10 different heavy metals (copper, lead, cobalt, chrome, iron, mercury, zinc, nickel, manganese and, cadmium) and for the presence of plasmid DNA. A total of eleven strains (67%) were resistant to at least one antibiotic. The most common resistance was observed against methicillin and oxacillin. The most resistance strains were found as Bacillus sp. B3 and Bacillus sp. B11. High heavy metal resistance against copper, chromium, zinc, iron and nickel was detected, but mercury and cobalt resistance was not detected, except for 3 strains (B3, B11, and B12) which showed mercury resistance. It has been determined that seven Bacillus strains have plasmids. The isolated plasmids were transformed into the Bacillus subtilis W168 and it was shown that heavy metal and antibiotic resistance determinants were carried on these plasmids. These results showed that there was a correlation between plasmid content and resistance for both antibiotic and heavy metal resistance.