Synergistic combination of colistin with imipenem, amikacine or ciprofloxacin against Acinetobacter baumannii and Pseudomonas aeruginosa carbapenem-resistant isolated in Annaba hospital Algeria

Abstract

Objective: The aim of this study is to detect in vitro the synergetic activity of colistin in combination with imipenem, amikacin or ciprofloxacin, at sub-inhibitory concentrations, against carbapenems-resistant (CR) Acinetobacter baumannii and Pseudomonas aeruginosa strains isolated from various wards in Annaba teaching hospital in eastern Algeria. Materials and Methods: The minimal inhibitory concentrations (MIC) were determined by broth macrodilution (BMD).Carbapenemase encoding genes were screened using polymerase chain reaction (PCR). The activity of colistin in combination with second antibiotic was evaluated by the Checkerboard Technique.Results: 39 CR P. aeruginosa and 21 CR A. baumanni strains where collected. The MIC values ranging from (0.25 to 4 µg/ml) to colistin, ≥16 µg/ml for imipenem, ≥4 µg/ml to amikacin and ≥8 µg/ml ciprofloxacin. The PCR reveals the presence of the genes bla OXA23 (n = 12), bla OXA24 (n = 6), bla NDM1 (n = 3) in A. baumannii and bla VIM2 (n = 12) in P. aeruginosa. The combination of colistin with imipenem showed synergistic effect on 57.14% and 46.15% of A. baumannii and P. aeruginosa isolates, respectively. For colistin and amikacin, the synergistic effect is detected in 28.6% of A. baumannii and 30.8% of P. aeruginosa. While colistin and ciprofloxacin showed synergy on 14.29% and 15.38% of A. baumannii and P. aeruginosa isolates, respectively. Conclusion: CR A. baumannii and P. aeruginosa remain the most prevalent infection agents in patients from high-risk wards at Annaba Hospital. Colistin associated with imipenem or with amikacin at sub-inhibitory concentrations gives very encouraging results allowing better management of infections caused by this type of bacteria.

Propranolol, chlorpromazine and diclofenac restore susceptibility of extensively drug-resistant (XDR)-Acinetobacter baumannii to fluoroquinolones

“…Little information is available on successful treatment regimens of A. baumannii by FQs combinations with antimicrobial or non-antimicrobial agents. Few attempts have been made so far to control the resistance of this strain [10,49]. Our results revealed that both doxycycline and colistin still retain good activities against A. baumannii.…”

Synthesis and potential antimicrobial activity of novel α-aminophosphonates derivatives bearing substituted quinoline or quinolone and thiazole moieties

“…All of them were isolated from patients hospitalized in the various departments at Annaba Hospital, Algeria. Their identification and susceptibility profile are reported by Toumi et al [ 55 ] and Meliani et al [ 56 ]. Four standard drugs Imipenem, Ciprofloxacin, Amikacine, and fluconazole were used as positive controls, while DMSO was used as a negative control in this study.…”