Cetinkaya Ebru, Coban Ahmet Yilmaz, Durupinar Belma
Ondokuz Mayis UIniversitesi Tip Fakültesi, Mikrobiyoloji ve Klinik Mikrobiyoloji Anabilim Dali, Samsun.
Mikrobiyol Bul. 2008 Oct;42(4):553-61.
The aim of this study was to investigate the effects of efflux pump inhibitors on the minimal inhibitory concentration (MIC) values of ciprofloxacin (CIP) in fluoroquinolone-resistant 42 Pseudomonas aeruginosa (n= 42), Escherichia coil (n= 97), Acinetobacter baumannii (n= 58) and Staphylococcus aureus (n= 80) strains isolated from clinical specimens. For this purpose phenylalanyl-arginyl-beta-naphthylamide (PA beta N) was used for P. aeruginosa, E. coli, A. baumannii and reserpine for S. aureus isolates as pump inhibitors. Fluoroquinolone resistance of the clinical isolates were determined by VITEK2 Compact (BioMerieux, France) automated system and confirmed with standard broth microdilution method. For the investigation of the effects of inhibitor agents, the MIC values were also determined in the presence of 25 microg/ml and 100 microg/ml PA beta N and 20 microg/ml reserpine. In the presence of 25 mg/l PA beta N, 61.9% of CIP resistant P. aeruginosa strains converted to susceptible ones, while this rate was 73.8% in the presence of 100 mg/l PA beta N. In A. baumannii clinical isolates, 8.6% and 15.5% of CIP-resistant strains have become susceptible in the presence of 25 mg/l and 100 mg/l PA beta N, respectively. Similarly the MIC values for CIP have decreased > or = 4 folds in 42.2%, and > or = 2 folds in 30.9% of E. coli isolates, in the presence of 25 mg/l PA beta N, however, there was no change in MICs of 26.9% of E. coli strains. The MIC values have also been lowered for > or = 4 folds in 83.6%, and two folds in 13.4% of E. coli strains by the use of 100 mg/l PA beta N concentration, however, no decrease in MIC values was detected in 3% of the isolates. 20 mg/l of reserpine have caused a decrease of > or = 4 folds in 8.75%, and two folds in 33.75% of S. aureus isolates, while there was no change in MIC values of 57.5% of S. aureus strains. Our results showed that PA beta N causes significant reduction in MIC values for CIP in the clinical isolates of P. aeruginosa, E. coli and A. baumannii and this effect may be attributed to efflux pump inhibition. In contrast, it was concluded that reserpine does not have a considerable effect on the MIC values of S. aureus against ciprofloxacin.
本研究旨在调查外排泵抑制剂对从临床标本中分离出的42株耐氟喹诺酮铜绿假单胞菌（n = 42）、97株大肠埃希菌（n = 97）、58株鲍曼不动杆菌（n = 58）和80株金黄色葡萄球菌（n = 80）菌株中，环丙沙星（CIP）的最低抑菌浓度（MIC）值的影响。为此，使用苯丙氨酰 - 精氨酰 - β - 萘酰胺（PAβN）作为铜绿假单胞菌、大肠埃希菌和鲍曼不动杆菌的泵抑制剂，利血平作为金黄色葡萄球菌分离株的泵抑制剂。临床分离株的氟喹诺酮耐药性通过VITEK2 Compact（法国生物梅里埃公司）自动化系统测定，并用标准肉汤微量稀释法进行确认。为了研究抑制剂的作用效果，还在存在25μg/ml和100μg/ml PAβN以及20μg/ml利血平的情况下测定MIC值。在存在25mg/l PAβN时，61.9%的耐CIP铜绿假单胞菌菌株转变为敏感菌株，而在存在100mg/l PAβN时，这一比例为73.8%。在鲍曼不动杆菌临床分离株中，分别有8.6%和15.5%的耐CIP菌株在存在25mg/l和100mg/l PAβN时变得敏感。同样，在存在25mg/l PAβN时，42.2%的大肠埃希菌分离株中CIP的MIC值降低≥4倍，30.9%的菌株降低≥2倍，然而，26.9%的大肠埃希菌菌株的MIC值没有变化。通过使用浓度为100mg/l的PAβN，83.6%的大肠埃希菌菌株的MIC值降低≥4倍，13.4%的菌株降低2倍，然而，3%的分离株中未检测到MIC值下降。20mg/l的利血平使8.75%的金黄色葡萄球菌分离株的MIC值降低≥4倍，33.75%的菌株降低2倍，而57.5%的金黄色葡萄球菌菌株的MIC值没有变化。我们的结果表明，PAβN可使铜绿假单胞菌、大肠埃希菌和鲍曼不动杆菌临床分离株中CIP的MIC值显著降低，这种作用可能归因于外排泵抑制。相比之下，得出的结论是利血平对金黄色葡萄球菌对环丙沙星的MIC值没有显著影响。
Antimicrob Agents Chemother. 2007-6
Pathol Biol (Paris). 1989-10
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