革兰阴性杆菌产AmpC酶和超广谱β-内酰胺酶的检测及耐药相关性

Detection and resistance correlation of AmpC and extended-spectrum β-lactamases in gram-negative bacilli

目的了解革兰阴性杆菌产AmpC酶和超广谱β-内酰胺酶(ESBLs)的情况及其耐药性,指导临床合理用药。方法K-B法检测184株革兰阴性杆菌对11种抗生素的耐药性;采用头孢西丁(FOX)药敏纸片进行AmpC酶的初筛,通过酶提取物三维试验方法确证产AmpC酶细菌;采用NCCLS推荐的纸片扩散确证试验检测184株革兰阴性杆菌中大肠埃希菌和肺炎克雷伯菌产ESBLs的情况。结果184株革兰阴性杆菌中,AmpC酶阳性率为23.3%,主要产生菌为鲍曼不动杆菌57.7%,铜绿假单胞菌37.5%,AmpC酶阳性菌对头孢噻肟(CTX)、头孢曲松(CRO)、复方新诺明(SXT)、左旋氧氟沙星(LEV)、哌拉西林(PRL)、氨曲南(ATM)、头孢他啶(CAZ)、阿米卡星(AK)、头孢吡肟(FEP)、美洛培南(MEM)的耐药率分别为94.7%、86.8%、84.2%、81.6%、71.0%、68.4%、68.4%、55.3%、50.0%、5.3%;38株大肠埃希菌和26株肺炎克雷伯菌中ESBLs阳性率分别为42.1%、23.1%,ESBLs阳性菌对头孢噻肟(CTX)、头孢曲松(CRO)、哌拉西林(PRL)、氨曲南(ATM)、复方新诺明(SXT)、头孢他啶(CAZ)的耐药率较高,对头孢吡肟(FEP)、阿米卡星(AK)、头孢西丁(FOX)、美洛培南(MEM)的耐药率较低,对左旋氧氟沙星(LEV)的耐药率大肠埃希菌则远高于肺炎克雷伯菌。结论在革兰阴性杆菌中,AmpC酶和ESBLs产生情况已相当严重,应重视对其的检测;产酶菌与非产酶菌对抗生素的耐药性有明显区别;临床用药以碳青霉烯类如美洛培南(MEM)为首选。

Objective] To understand the actuality and resistance of AmpC and extended-spectrumβ-lactamases in gram-negative bacilli and help us medicate reasonably in clinic. [Methods] Resistance to 11 antibiotic agents was tested by K-B disc method in 184 gram-negative bacilli; AmpC was screened by cefoxitin and confirmed by the three dimensional extract test; among E. coli and K.peumoniae of 184 gram-negative bacilli, ESBLs were detected by the disk diffusion method described in NCCLS. [Results] Among 184 gram-negative bacilli, producing AmpC stains accounted for 23.3%, of which A.baumannii and P.aeruginosa were 57.7% and 37.5% respectively; the resistance rate of producing AmpC stains to cefotaxime, ceftriaxone, trimethoprim/sulfa,levofloxacin, piperacillin, aztreonam, ceftazidime, amikacin, cefepime, merep- enem were 94.7%, 86.8%, 84.2%, 81.6%, 71.0%, 68.4%, 68.4%, 55.3%, 50.0%, 5.3% respectively. The rate of ESBLs in 38 E.coli isolates and 26 K.peumoniae isolates were 42.1% and 23.1% respectively; the resistance rate of cefotaxime, ceftriaxone, piperacillin, aztreonam, trimethoprim/sulfa, ceftazidime was high; the resistance rate of cefepime, amikacin, cefoxitin, meropenem was low; the resistance rate of levofloxacin in E.coli was higer than in K.peumoniae. [Conehlsion] The preduction situation of AmpC and ESBLs in gram-negative bacilli are considerably severe and should be detected carefully; between producing β-lactamase and non-producing β-lactamase stains, the resistance to antibiotic shows the apparent difference. We can choose meropenem as the best clinical medication.