Molecular investigation of plasmid or chromosomal mediated extended spectrum beta-lactamases existance in Escherichia coli, Klebsiella and Acinetobacter strains

In this study, total of 94 strains isolated from various culture samples which belong to patients applied to Microbiology Laboratory of Gazi University Medical Faculty Hospital were investigated. 53,2%, 20,2%, 18,1%, 4,3%, 2,1% and 2,1% of isolates were termed as Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Klebsiella oxytoca, Klebsiella terrigena and Klebsiella ornithinolytica respectively. In strains existence of extended spectrum beta lactamase (ESBL) was determined by double disk sinergy test (DDST). In a result of DDST, it was detected that 69% of strains produced ESBL, 31% of strains didn?t produce ESBL. Plasmid DNAs of the isolates were isolated. 71 of the isolates contained from 1 to 10 plasmid DNA changing from 0,4 kb to 19,3 kb in size while 23 isolates had no plasmid DNA. ESBL positive 58 strains were treated with acridine orange (AO) solution and plasmid DNA reisolated. Plasmid DNA bands which 81% of strains treated with AO were thinner than plasmid DNA bands not threated with AO. In a result of DDST, antibiotics resistance of 6,9% of strains were more less than strains not treated with AO. So, it was thought that existence of ESBL was as a plasmid origin in 6,9% of strains. 93,1% of strains were thought to be as a chromosomal origin because of all plasmids weren?t cured with AO. TEM, SHV, CTX-M and OXA primers were designed for enzyme typing of isolates. Target sequence were amplified by polimerase chain reaction (PCR). PCR products were sequenced and they were compared with DNA gene bank sequences in BLAST software. According to this, 50%, 14,87% and 11,7% of strains were detected as TEM, SHV and CTX-M types ESBL respectively. There is no ESBL types in 23,43% of strains. In PCR two isolate which couldn?t detected in DDST were found ESBL positive.