Effect of Combination of Antibiotics on Enterobacter cloacae isolated from Different Clinical and Environmental Sources in Diyala Province

Abstract

This study included collection of 300 clinical and environmental samples (vaginal swabs, wounds, hands of the workers, patients' bed, surgical tools, and floors) from the hospitals of Diyala Province. The results showed that 40 (21.6%) of the isolates were belonging to Enterobacteriaceae and 10 (25%) were Enterobacter cloacae, by using diagnostic phenotypic, biochemical tests and the identification was confirmed by using regular api20E and VITEK 2 system. The results of the investigation of some virulence factors showed that Enterobacter cloacae was not able to produce haemolysin. The formation of biofilm was detected by micrometer tube method, and Enterobacter cloacae was able to formation biofilm at a percentage of 90%, while all isolates of Enterobacter cloacae were not able to produce urease. All the isolates (100%) have Siderophores, 70% of the isolates were able to produce bacteriocin, while 60% of the isolates were able to produce -lactamase. In regards to the resistance to antibiotics, the results showed that 90% of the isolates were resistant to cefixime and tobramycin. imipenem was the most effective antibiotic and showed 100% activity. The minimum inhibitory concentration (MIC) for 5 antibiotics (amoxicillin, cefotaxime, ciprofloxacin, streptomycin, and nalidixic acid) ranged between 64-1024, 32-1024, 2-1024, 128-1024, 8-1024 µg\ml for the five antibiotics, respectively. The results showed that the combination of ciprofloxacin, streptomycin, and cefotaxime at a ratio of 1:3 was the best among other ratios, while the combination of cefotaxime and ciprofloxacin showed 80% synergistic effects against four isolates. In addition, combination of streptomycin and cefotaxime showed 80% synergistic effect against four isolates. Outcome of the plasmid profile for the isolates Enterobacter cloacae1 indicated that isolate contains one band of mega plasmid. Curing was conducted by using acridin orange and plasmids were lost at a concentration of 1024 µg / ml for Enterobacter cloacae1. Results indicate that all isolates showed resistance to antibiotics ciprofloxacin and Co-trimoxazole, while lost resistance to amikacin, augmentin, ampicillin, gentamycin and cefotaxime. Keywords: Enterobacter cloacae, Virulence factors, Antibiotics, Plasmid curing.