膝关节液中产气巴斯德菌的耐药性及耐药机制研究

Drug resistance and resistant mechanisms of Pasteurella aerogenes from knee joint fluid

目的探讨产气巴斯德菌耐药性及耐药机制。方法用美国BD公司PhoenixTMl00全自动细菌鉴定/药敏仪,对膝关节炎患者膝关节液分离的1株病原菌进行鉴定,并对21种抗菌药物的敏感性进行检测,应用头孢硝噻吩(Ncf)试验检测其β-内酰胺酶(BLs),多底物纸片法分类检测β-内酰胺酶。结果 PhoenixTMl00细菌鉴定仪鉴定该菌为产气巴斯德菌,可信度(ID)为94.0%;对氨曲南、头孢他啶耐药,对氨苄西林、氨苄西林/舒巴坦、阿莫西林/克拉维酸、哌拉西林、哌拉西林/他唑巴坦、头孢唑林、头孢西丁、头孢噻肟、头孢吡肟、碳青霉烯类、氨基糖苷类、四环素类、氯霉素、多黏菌素、氟喹诺酮类、磺胺甲噁唑/甲氧苄啶敏感;BLs的分类检测中,氨曲南为6mm,耐药,与头孢他啶/克拉维酸、氨苄西林/舒巴坦均无协同及拮抗,头孢他啶为10mm,耐药,头孢他啶/克拉维酸及头孢噻肟均为14mm,头孢噻肟/克拉维酸为16mm,头孢西丁为28mm,均敏感。结论该产气巴斯德菌临床分离株仅对部分β-内酰胺类药物耐药(耐药性较低),其机制为产BLs,耐药表型及克拉维酸协同试验阳性,推测为产某种产超广谱β-内酰胺酶(ESBLs)。

OBJECTIVE To investigate the drug resistance and resistant mechanisms of β-lactam of Pasteurella aerogenes（P.aero）from the joint fluid of a patient with knee osteoarthritis. METHODS One pathogenic bacteria isolated from the knee joint fluid of the patient with knee osteoarthritis was identified by BD＇s phoenixTM100,and 21 antibacterial agents were detected for susceptibility with nitrocefin test（Ncf） for β-lactamase（BLs） and a multi-disk test for the variety of BLs. RESULTS The strain was identificated by phoenixTMl00 as P.aerogenes with ID of 94%;the strain was resistant to ceftazidime and aztreonam,but susceptible to ampcillin,ampcillin/sulbactam,piperacillin,piperacillin/tazobactam,penicillins,amocillin amocillin/clavulanate,cefoxitin,and cephalothin,cefotaxime,cefepime,imipenem,meropenem,aminoglycosides,tetracyclines,chloramphenicol,polymyxin,fluoroquinolon and trimethoprim/sulfamethoxazole;During the detection of the variety of BLs,6mm for aztreonam was detected but was drug-resistant,while there were no synergy or antagonism between ceftazidime/clavulanate,ampicillin/sulbactam.Meanwhile,10 mm ceftazidime was detected as well as 14 mm ceftazidime/clavulanate,14mm cefotaxime,16mm cefotaxime/clavulanate and 28mm cefoxitin were all susceptible. CONCLUSION The clinical isolate of P.aerogenes from joint fluid of a patient with knee osteoarthritis is just resistant to some of β-lactams,thus the drug resistance is low,and the resistant mechanism of P.aerogenes is the production of BLs,being speculated to produce ESBLs by phenotype of drug resistant and ceftazidime-clavulanate synergy test.