Identification of bacterial strains isolated from patients with urinary tract infection and the role of plasmids in their antibiotic resistance.Identification of bacterial strains isolated from patients with urinary tract infection and the role of pla

One hundred fifty bacterial strains were isolated from patients with rinary tract infections (UTIs). They were belonging to ten different species of gram - negative bacteria and two genera of gram-positive bacteria. E.coli was the major causative agent and comprise 40% of all cases. Klebsiella pneumonia and Proteus mirabilis were the second and the third with 18.67% and 18.0% respectively. Other gram - negative bacteria were belong to the genera Enterobacter, Acintobacter, Pseudomonas, Citrobacter, and Serratia. Ten cases (6.67%) were caused by genus Staphylococcus and seven (4.66%) were caused by Streptococcus. Out of the 150 positive causes, 96 (64%) were from female patients, while 54 (36%) were from males. High percentage of all isolates was resistance to all used antibiotics except for the nitrofurantion to which all isolates were sensitive. The second most effective antibiotic for all isolates was nalidixic acid (25% of all isolates were resistant), while the gentamycin was the third most effective antibiotic (39% were resistant). 75% of E. coli isolates and 86% of all isolates were resistant to ampicillin. High percentage of resistance to antibiotics is a reflection for the misuse of antibiotics. Plasmid content of six multiresisntant E. coli strainswas determined. A number of plasmids detected in these strains ranged from one to seven plasmids. Although, the plasmid fingerprinting of the six strains were different, some plasmids were found to common for more than one strain. There was no direct relationship between the plasmid profile and the antimicrobial resistance patterns. Some strains showed similar antibiotic resistance patterns and different plasmid profile. Conjugation experiments showed that Ecoli strains harbor variety of self transmissible plasimds carrying antibiotic resistance genes (either singly or in combination of two or more). One plasmid was found to carry resistance genes for tetracycline (TEr), chloramphenicol (Cr), streptomycin (Sr), and trimethoprime (STXr). It seems that this plasimd is widely spread in the Iraqi isolates since it was detected in all the three examined E. coli strains. Another conjugative plasmid was found to carry resistance to ampicillin, gentamicin, neomycin, and streptomycin. No conjugation was detected between E. coli and other members of Enterobacteriaceae like Proteus, Serratia, and Acin tobacter. Transformation of E. coli HB101 with total plasmid DNA isolated from several multidrug resistant E.coli strains showed that the tetracycline resistance gene and nalidixic acid resistance gene cannot transfer by transformation, while the streptomycin resistance," ampcillin resistance and neomycin resistance genes can be transfer readily by transformation. Conjugation and transformation experiments revealed the following: l-Tetracycline__resistance gene in all studied E. coli strains can be transferred by conjugation, but not by transformation indicating that this gene is located on large self transmissible plasmid. 2- Nalidixic acid resistance gene is located on the chromosome since it \ was un able to transfer either by conjugation or transformation. 3- The ampicillin resistance, streptomycin resistance, and neomycin resistance genes are either located on large self transmissible plasmids and so transfer by conjugation, or they can be carried on small non conjugative plasmids.