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Spread of Efflux Pump Overexpressing-Mediated Fluoroquinolone Resistance and Multidrug Resistance in Pseudomonas aeruginosa by using an Efflux Pump Inhibitor.

Adabi M, Talebi-Taher M, Arbabi L, Afshar M, Fathizadeh S, Minaeian S, Moghadam-Maragheh N, Majidpour A - Infect Chemother (2015)

Bottom Line: We designed this study to investigate the efflux pump mediated fluoroquinolone resistance and check the increasing effectiveness of fluoroquinolones in combination with an efflux pumps inhibitor among P. aeruginosa isolates from burn wounds infections.All of Ciprofloxacin resistant isolates were positive for MexA, MexC and MexE genes simultaneously.Early recognition of this resistance mechanism should allow the use of alternative antibiotics and use an efflux pumps inhibitor in combination with antibiotic therapy.

View Article: PubMed Central - PubMed

Affiliation: Antimicrobial Resistance Research Center, Iran University of Medical Sciences, Tehran, Iran.

ABSTRACT

Background: Fluoroquinolone resistance in Pseudomonas aeruginosa may be due to efflux pump overexpression and/or target mutations. We designed this study to investigate the efflux pump mediated fluoroquinolone resistance and check the increasing effectiveness of fluoroquinolones in combination with an efflux pumps inhibitor among P. aeruginosa isolates from burn wounds infections.

Materials and methods: A total of 154 consecutive strains of P. aeruginosa were recovered from separate patients hospitalized in a burn hospital, Tehran, Iran. The isolates first were studied by disk diffusion antibiogram for 11 antibiotics and then minimum inhibitory concentration (MIC) experiments were performed to detect synergy between ciprofloxacin and the efflux pump inhibitor, carbonyl cyanide-m-chlorophenyl hydrazone (CCCP). Then to elucidate the inducing of multi drug resistance due to different efflux pumps activation in Fluoroquinolone resistant isolates, synergy experiments were also performed in random ciprofloxacin resistant isolates which have overexpressed efflux pumps phenotypically, using CCCP and selected antibiotics as markers for Beta-lactams and Aminoglycosides. The isolates were also tested by polymerase chain reaction (PCR) for the presence of the MexA, MexC and MexE, which encode the efflux pumps MexAB-OprM, MexCD-OprJ and MexEF-OprN.

Results: Most of the isolates were resistant to 3 or more antibiotics tested. More than half of the ciprofloxacin resistant isolates exhibited synergy between ciprofloxacin and CCCP, indicating the efflux pump activity contributed to the ciprofloxacin resistance. Also increased susceptibility of random ciprofloxacin resistant isolates of P. aeruginosa to other selected antibiotics, in presence of CCCP, implied multidrug extrusion by different active efflux pump in fluoroquinolones resistant strains. All of Ciprofloxacin resistant isolates were positive for MexA, MexC and MexE genes simultaneously.

Conclusion: In this burn hospital, where multidrug resistant P. aeruginosa isolates were prevalent, ciprofloxacin resistance and multidrug resistance due to the overexpression of fluoroquinolones mediated efflux pumps has also now emerged. Early recognition of this resistance mechanism should allow the use of alternative antibiotics and use an efflux pumps inhibitor in combination with antibiotic therapy.

No MeSH data available.


Related in: MedlinePlus

The susceptibility status of the isolates against 11 studied antibiotics according to disk diffusion. IMI, imipenem; CEF, cefepime; TC, ticarcillin; AT, aztreonam; TOB, tobramycin; GN, gentamicin; CO, colistin; CIP, ciprofloxacin; AK, amikacin; PTZ, piperacillin-tazobactam; PIP, piperacillin.
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Figure 1: The susceptibility status of the isolates against 11 studied antibiotics according to disk diffusion. IMI, imipenem; CEF, cefepime; TC, ticarcillin; AT, aztreonam; TOB, tobramycin; GN, gentamicin; CO, colistin; CIP, ciprofloxacin; AK, amikacin; PTZ, piperacillin-tazobactam; PIP, piperacillin.

Mentions: 154 strains of P. aeruginosa were isolated from hospitalized burned patients and confirmed using biochemical tests and confirmatory PCR assays. The antibiogram results representing 143 (92.8%) of the P. aeruginosa isolates exhibiting resistance to two or more antibiotics. According to our antibiogram results, all of the isolates only were susceptible to colistin. The most resistance was seen against tobramycin (87.7%) and the least resistance was seen against aztreonam (71.4%).The preliminary results of ciprofloxacin susceptibility test using the disk agar diffusion method showed that 85.1% of the P.aeruginosa strains were resistant to this antibiotic. Figure 1 summarizes the susceptibility status of the isolates against 11 studied antibiotics according to disk diffusion method. MIC for ciprofloxacin ranged from 0.5 to 128 mg/L, According to the established breakpoint values recommended by CLSI [20]. The P.aeruginosa isolates with MIC ≥ 4 mg/L are considered as ciprofloxacin resistant. The preliminary results of ciprofloxacin susceptibility test using the MIC method showed that 127 (82.5%) of the P. aeruginosa strains were resistant to this antibiotic. Results of Synergy tests indicated that by using CCCP as EPI, the MICs of ciprofloxacin for 51 (61%) of the ciprofloxacin resistant isolates decreased (2 to 256 folds) on the CCCP-supplemented plate. Table 2 shows the Effects of CCCP on the Ciprofloxacin MIC reduction in ciprofloxacin resistant isolates of P. aeruginosa. Also in other synergy tests by using CCCP and other antibiotics, we observed increased susceptibility of random selected ciprofloxacin resistant isolates to selected antibiotics as markers for beta-lactams [imipenem (IMI) & cefepime (CEF)] and Aminoglycosides [gentamicin (GEN)]. Table 3 shows the MIC values for ciprofloxacin measured in the absence and in the presence of 12.5 µm CCCP as efflux pump inhibitor in clinical strains of P. aeruginosa. The MexA, MexC and MexE genes were amplified by PCR in 147 (95.4%) isolates simultaneously, and 5 (3.2%) isolates revealed the presence of MexA and MexE simultaneously. 1 (0.6%) isolate had only the MexE gen and 1 (0.6%) had none of the Mex genes. All of the ciprofloxacin resistant isolate had MexA, MexC and MexE genes simultaneously.


Spread of Efflux Pump Overexpressing-Mediated Fluoroquinolone Resistance and Multidrug Resistance in Pseudomonas aeruginosa by using an Efflux Pump Inhibitor.

Adabi M, Talebi-Taher M, Arbabi L, Afshar M, Fathizadeh S, Minaeian S, Moghadam-Maragheh N, Majidpour A - Infect Chemother (2015)

The susceptibility status of the isolates against 11 studied antibiotics according to disk diffusion. IMI, imipenem; CEF, cefepime; TC, ticarcillin; AT, aztreonam; TOB, tobramycin; GN, gentamicin; CO, colistin; CIP, ciprofloxacin; AK, amikacin; PTZ, piperacillin-tazobactam; PIP, piperacillin.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4495281&req=5

Figure 1: The susceptibility status of the isolates against 11 studied antibiotics according to disk diffusion. IMI, imipenem; CEF, cefepime; TC, ticarcillin; AT, aztreonam; TOB, tobramycin; GN, gentamicin; CO, colistin; CIP, ciprofloxacin; AK, amikacin; PTZ, piperacillin-tazobactam; PIP, piperacillin.
Mentions: 154 strains of P. aeruginosa were isolated from hospitalized burned patients and confirmed using biochemical tests and confirmatory PCR assays. The antibiogram results representing 143 (92.8%) of the P. aeruginosa isolates exhibiting resistance to two or more antibiotics. According to our antibiogram results, all of the isolates only were susceptible to colistin. The most resistance was seen against tobramycin (87.7%) and the least resistance was seen against aztreonam (71.4%).The preliminary results of ciprofloxacin susceptibility test using the disk agar diffusion method showed that 85.1% of the P.aeruginosa strains were resistant to this antibiotic. Figure 1 summarizes the susceptibility status of the isolates against 11 studied antibiotics according to disk diffusion method. MIC for ciprofloxacin ranged from 0.5 to 128 mg/L, According to the established breakpoint values recommended by CLSI [20]. The P.aeruginosa isolates with MIC ≥ 4 mg/L are considered as ciprofloxacin resistant. The preliminary results of ciprofloxacin susceptibility test using the MIC method showed that 127 (82.5%) of the P. aeruginosa strains were resistant to this antibiotic. Results of Synergy tests indicated that by using CCCP as EPI, the MICs of ciprofloxacin for 51 (61%) of the ciprofloxacin resistant isolates decreased (2 to 256 folds) on the CCCP-supplemented plate. Table 2 shows the Effects of CCCP on the Ciprofloxacin MIC reduction in ciprofloxacin resistant isolates of P. aeruginosa. Also in other synergy tests by using CCCP and other antibiotics, we observed increased susceptibility of random selected ciprofloxacin resistant isolates to selected antibiotics as markers for beta-lactams [imipenem (IMI) & cefepime (CEF)] and Aminoglycosides [gentamicin (GEN)]. Table 3 shows the MIC values for ciprofloxacin measured in the absence and in the presence of 12.5 µm CCCP as efflux pump inhibitor in clinical strains of P. aeruginosa. The MexA, MexC and MexE genes were amplified by PCR in 147 (95.4%) isolates simultaneously, and 5 (3.2%) isolates revealed the presence of MexA and MexE simultaneously. 1 (0.6%) isolate had only the MexE gen and 1 (0.6%) had none of the Mex genes. All of the ciprofloxacin resistant isolate had MexA, MexC and MexE genes simultaneously.

Bottom Line: We designed this study to investigate the efflux pump mediated fluoroquinolone resistance and check the increasing effectiveness of fluoroquinolones in combination with an efflux pumps inhibitor among P. aeruginosa isolates from burn wounds infections.All of Ciprofloxacin resistant isolates were positive for MexA, MexC and MexE genes simultaneously.Early recognition of this resistance mechanism should allow the use of alternative antibiotics and use an efflux pumps inhibitor in combination with antibiotic therapy.

View Article: PubMed Central - PubMed

Affiliation: Antimicrobial Resistance Research Center, Iran University of Medical Sciences, Tehran, Iran.

ABSTRACT

Background: Fluoroquinolone resistance in Pseudomonas aeruginosa may be due to efflux pump overexpression and/or target mutations. We designed this study to investigate the efflux pump mediated fluoroquinolone resistance and check the increasing effectiveness of fluoroquinolones in combination with an efflux pumps inhibitor among P. aeruginosa isolates from burn wounds infections.

Materials and methods: A total of 154 consecutive strains of P. aeruginosa were recovered from separate patients hospitalized in a burn hospital, Tehran, Iran. The isolates first were studied by disk diffusion antibiogram for 11 antibiotics and then minimum inhibitory concentration (MIC) experiments were performed to detect synergy between ciprofloxacin and the efflux pump inhibitor, carbonyl cyanide-m-chlorophenyl hydrazone (CCCP). Then to elucidate the inducing of multi drug resistance due to different efflux pumps activation in Fluoroquinolone resistant isolates, synergy experiments were also performed in random ciprofloxacin resistant isolates which have overexpressed efflux pumps phenotypically, using CCCP and selected antibiotics as markers for Beta-lactams and Aminoglycosides. The isolates were also tested by polymerase chain reaction (PCR) for the presence of the MexA, MexC and MexE, which encode the efflux pumps MexAB-OprM, MexCD-OprJ and MexEF-OprN.

Results: Most of the isolates were resistant to 3 or more antibiotics tested. More than half of the ciprofloxacin resistant isolates exhibited synergy between ciprofloxacin and CCCP, indicating the efflux pump activity contributed to the ciprofloxacin resistance. Also increased susceptibility of random ciprofloxacin resistant isolates of P. aeruginosa to other selected antibiotics, in presence of CCCP, implied multidrug extrusion by different active efflux pump in fluoroquinolones resistant strains. All of Ciprofloxacin resistant isolates were positive for MexA, MexC and MexE genes simultaneously.

Conclusion: In this burn hospital, where multidrug resistant P. aeruginosa isolates were prevalent, ciprofloxacin resistance and multidrug resistance due to the overexpression of fluoroquinolones mediated efflux pumps has also now emerged. Early recognition of this resistance mechanism should allow the use of alternative antibiotics and use an efflux pumps inhibitor in combination with antibiotic therapy.

No MeSH data available.


Related in: MedlinePlus