Curing of Plasmid DNA Content of Bacteria Isolated from Urinary Tract Infection


Twenty-five bacterial isolates were collected from patients with urinary tract infection from Hospitals in Mosul city. The isolates were identified by the morphological, cultural and biochemical tests . The results showed that 18 isolates belong to Escherichia coli, 3 Klebsiella pneumoniae, 3 Proteus mirabilis and 1 Pseudomonas aeruginosa. The resistance of these bacterial isolates was tested against antibiotics and heavy metals such as mercuric chloride, cadmium chloride and nickel chloride. Four isolates belonging to different genera; E. coli, K. pneumoniae, Pr. mirabilis and P. aeruginosa chosen to eliminate their plasmid DNA content by using different curing agents; the antimicrobial agents Erythromycin, Nalidixic acid, Methoprim and Chloramphenicol were used at one half and one quarter of the minimum inhibitory concentration(MIC). Nalidixic acid was the most effective one in curing antibiotic and heavy metal resistance in K. pneumoniae in a frequency ranged between (4-100). The acidic pH at a value of 5.5 was used to cure the bacterial isolates resistance and P. aeruginosa was the most effected one and it showed a ratio of (11-96%) while E. coli revealed curing of studied traits by elevated temperature 44 °C in a ratio of( 4-100%) . The effect of these curing agents on some other phenotypic traits was studied and mucus production of K. pneumoniae cured at a frequency of 40% by Nalidixic acid.