ABSTRACT
Infection is an important cause of mortality in patients with burns. Rapid emergence of hospital pathogens and antibiotic-resistant organisms necessitate periodic evaluation of bacterial colonization patterns and antibiogram sensitivity in burn wards. Sixty isolates from wounds of burns were collected from two hospitals in Cairo, Egypt along the period of 12 months in 2013. Antibiotic sensitivity of these isolates was assessed by single disk diffusion method. Multi drug resistance percentage and the most prevalent resistance phenotype among bacterial isolates were recorded. In addition, 19 essential oils were tested against the MDR isolates. The most potent oils were analyzed by GC-MS to determine their main chemical constituents. According to microbiological and biochemical identification method, Pseudomonas aeruginosa was the most dominant organism 23 (38%), followed by Staphylococcus aureus 16 (27%), Klebsiella spp. 11 (18%), Acinetobacter spp. 4 (7%). Three isolates of Escherichia coli (5%) and three isolates of Proteus spp. (5%). Piperacillin-tazobactam, imipenem and linezolid antibiotics were the most effective antibiotics against Pseudomonas aeruginosa, Enterobacteriaceae and S. aureus isolates respectively. Cinnamon and thyme essential oils were the most potent oils against the multi drug resistant burn wound isolate. Cinnamaldehyde (60.7%) and ρ-cymene (50%) were the major chemical constituents in cinnamon and thyme essential oils, respectively. It is clear that antibiotic resistance levels are high among the examined bacterial isolates of burn wounds. This study could be useful for physician to better choice of empiric therapy. Cinnamon and thyme may be used as a promising an alternative medicine for the treatment of burn wound infections.
ABSTRACT
OBJECTIVES: To study the potential factors include gene mutation, efflux pump and alteration of permeability associated with quinolone-resistance of Salmonella enterica strains isolated from patients with acute gastroenteritis and to evaluate the degree of synergistic activity of efflux pump inhibitors when combined with ciprofloxacin against resistant isolates. METHODS: Antimicrobial resistance patterns of fifty-eight Salmonella isolates were tested. Five isolates were selected to study the mechanism of resistance associated with quinolone group, including mutation in topoisomerase-encoding gene, altered cell permeability, and expression of an active efflux system. In addition, the combination between antibiotics and efflux pump inhibitors to overcome the microbial resistance was evaluated. RESULTS: Five Salmonella isolates totally resistant to all quinolones were studied. All isolates showed alterations in outer membrane proteins including disappearance of some or all of these proteins (Omp-A, Omp-C, Omp-D and Omp-F). Minimum inhibitory concentration values of ciprofloxacin were determined in the presence/absence of the efflux pump inhibitors: carbonyl cyanide m-chlorophenylhydrazone, norepinephrin and trimethoprim. Minimum inhibitory concentration values for two of the isolates were 2-4 fold lower with the addition of efflux pump inhibitors. All five Salmonella isolates were amplified for gyrA and parC genes and only two isolates were sequenced. S. Enteritidis 22 had double mutations at codon 83 and 87 in addition to three mutations at parC at codons 67, 76 and 80 whereas S. Typhimurium 57 had three mutations at codons 83, 87 and 119, but no mutations at parC. CONCLUSIONS: Efflux pump inhibitors may inhibit the major AcrAB-TolC in Salmonella efflux systems which are the major efflux pumps responsible for multidrug resistance in Gramnegative clinical isolates.