Buchunde S, Mendiratta D K, Deotale V, Narang P
Department of Microbiology, Mahatma Gandhi Institute of Medical Sciences, Sevagram, Wardha, Maharashtra, India.
Indian J Med Microbiol. 2012 Apr-Jun;30(2):170-4. doi: 10.4103/0255-0857.96683.
The present study was undertaken to evaluate the screening antibiotic, confirmatory phenotypic test and agent against PCR as gold standard and to detect the prevalent MBL gene.
Three hundred and twenty-six Pseudomonas aeruginosa isolates were screened for resistance to Imipenem (IPM), Meropemem (MEM) and Ceftazidime (CAZ) by disc diffusion. Isolates resistant to any of these were considered screen test-positive for MBL and were subjected to Double disc synergy test (DDST) and Disc potentiation test (DPT: Using IPM, MEM and CAZ alone and with EDTA), Minimum inhibitory concentration (MIC) reduction [four-fold or more reduction in MIC of IPM and MEM in presence of chelators: EDTA and 1,10-phenanthroline (EPI/EPM: EDTA-phenanthroline- Imipenem/Meropenem Broth Microdilution method)] and polymerase chain reaction (PCR) for blaIMP and blaVIM .
Screen test-positives by MEM and CAZ were 19.3% as against 17.8% by IPM. MEMDDST, DPT and EPM confirmed 100% screen-test positives as against 93.7% by CAZ DDST and DPT-2, 76.2% by CAZ DPT-1, 88.9% by IPM DDST, 85.7% by IPM DPT-1 and 92.1% by EPI. IPMand CAZ DDST together confirmed 100% while IPM and CAZ DPT-2 confirmed 96.8%. All 63 screen-test positives showed the presence of blaVIM .
MEM was found to be the best screening and confirmatory agent for MBL detection and blaVIM was found to be the prevalent MBL gene in this part of the country.
本研究旨在评估作为金标准的筛选抗生素、确证性表型试验及针对PCR的试剂，并检测流行的金属β-内酰胺酶（MBL）基因。
采用纸片扩散法对326株铜绿假单胞菌分离株进行亚胺培南（IPM）、美罗培南（MEM）和头孢他啶（CAZ）耐药性筛选。对其中任何一种耐药的分离株被视为MBL筛选试验阳性，并进行双纸片协同试验（DDST）和纸片增效试验（DPT：单独使用IPM、MEM和CAZ以及与乙二胺四乙酸（EDTA）联合使用）、最低抑菌浓度（MIC）降低[在螯合剂存在下IPM和MEM的MIC降低四倍或更多：EDTA和1,10-菲啰啉（EPI/EPM：EDTA-菲啰啉-亚胺培南/美罗培南肉汤微量稀释法）]以及针对blaIMP和blaVIM的聚合酶链反应（PCR）。
MEM和CAZ筛选试验阳性率分别为19.3%，而IPM为17.8%。MEM DDST、DPT和EPM确证了100%的筛选试验阳性，而CAZ DDST和DPT-2为93.7%，CAZ DPT-1为76.2%，IPM DDST为88.9%，IPM DPT-1为85.7%，EPI为92.1%。IPM和CAZ DDST共同确证率为100%，而IPM和CAZ DPT-2为96.8%。所有63例筛选试验阳性均显示blaVIM存在。
发现MEM是检测MBL的最佳筛选和确证试剂，且blaVIM是该国该地区流行的MBL基因。
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