Antimicrobial Resistance Pattern and Plasmid Analysis of Escherichia coli from Patients Suffering from Acute Diarrhoea in Azad Kashmir, Pakistan

摘要

The antimicrobial susceptibility patterns of 1210 Escherichia coli isolated from diarrhoeal patients admitted to hospitals in Azad Kashmir, Pakistan were analyzed from 1994 to 1998 to determine their changing trends in response to fifteen antibiotics. The isolates showed highest resistance against carbenicillin followed by ampicillin, ceftizoxime, co-trimoxazole, streptomycin, amoxicillin, amikacin, tetracycline, erythromycin, nalidixic acid and chloramphenicol. The isolates showed least resistance against ciprofloxacin followed by ceftriaxone and gentamicin. All E. coli isolates were sensitive to cefixime. Majority (58%) of E. coli strains were recovered from children and 57% were from male patients. Most of the diarrhoeal cases were recovered in summer (36.4%) followed by 35.9% in autumn, 17.7% in spring, and 9.8% in winter. The highest number of stool specimens infected with E. coli (40.8%) was recovered in 1998 and the lowest (21.8%) in 1995. It was also observed that the percentage of isolates resistant to any of the antibiotics tested was higher in children than in adults. Resistance of E. coli isolates to 3-10 antibiotics was recorded at different concentrations: 49% were resistant at 25 mu g/ml, 46% at 50 mu g/ml, 23% at 100 mu g/ml and 10% were resistant to three or more antibiotics at 300 mu g/ml. The most common antibiotics resistance pattern was CaACXM. The plasmids were observed in 31.2% strains of E. coli resistant to three or more antibiotics. The number of plasmids, varied from one to five. Analysis of plasmid DNA of E. coli revealed that all the strains contained a heterogeneous population of plasmids ranging between 23.1 kb to 2.0 kb and were grouped into nine different plasmid patterns. The 23.1 Kb plasmid could only confer ampicillin, chloramphenicol and tetracycline resistance to the competent cells of E. coli HB101.