使用头孢吡肟和他唑巴坦增强AmpC共产生菌中ESBL的表型检测
Enhancing Phenotypic Detection of ESBL in AmpC co-producers by using Cefepime and Tazobactam.
作者信息
Kaur Jaspal, Mahajan Gomty, Chand Kailash, Chopra Shashi
机构信息
Associate Professor, Department of Microbiology, Punjab Institute of Medical Sciences , Jalandhar, India .
Professor, Department of Microbiology, Punjab Institute of Medical Sciences , Jalandhar, India .
出版信息
J Clin Diagn Res. 2016 Jan;10(1):DC05-8. doi: 10.7860/JCDR/2016/15264.7041. Epub 2016 Jan 1.
INTRODUCTION
Routine phenotypic methods employing clavulanate and third generation cephalosporins to detect ESBL are not promising for isolates that co-produce an inhibitor-resistant beta lactamase like AmpC.
AIM
Enhancing phenotypic detection of ESBL in AmpC co-producers by using cefepime and tazobactam.
MATERIALS AND METHODS
A total of 245 isolates of Escherichia coli (123), Klebsiella spp. (87), Proteus spp.(20), Enterobacter spp. (9) and Citrobacter spp.(6) obtained over a period of 2 years from January 2013 to December 2014 from urine samples of hospitalized patients were studied. The isolates were simultaneously screened for ESBL and AmpC production. AmpC production was confirmed by modified three -dimensional test (MTDT). ESBL production was confirmed by original double disc synergy test, phenotypic disc confirmatory test (PDCT) and modified double disc synergy test (MDDST) and the results compared.
RESULTS
AmpC production was confirmed in 113 (46.1%) isolates by modified three dimensional test out of 143 screened positive for AmpC. Of the 192 isolates screened positive for ESBL, ESBL production was confirmed in 162 (66.1%). DDST detected ESBLs in only134 (54.7%) while additional 28 (11.4%) ESBL positive isolates were detected by MDDST. PDCT detected total 145(59.2%) ESBL positive isolates, with cefotaxime and cefotaxime + clavulanate detecting 139 (56.7%) and ceftazidime and ceftazidime + clavulanate detecting additional 6 isolates. All the 28 (11.4%) isolates which were additionally detected ESBL producers by MDDST showed positive three dimensional test i.e. AmpC co producers. DDST detected ESBL in none of AmpC positive isolates while PDCT detected ESBL in 11 isolates showing AmpC co-production. In MDDST cefepime was the best cephalosporin in detecting ESBL in presence of AmpC production. It showed synergism with amoxicillin-clavulanate in 11(39.3%) isolates and in 24(85.7%) isolates with piperacillin-tazobactam. Third generation cephalosporins -cefotaxime, ceftazidime and cefpodoxime were not able to detect ESBL in AmpC-co producers.
CONCLUSION
Modification of double disc synergy tests that combine piperacillin-tazobactum with cefepime enhances the possibility of ESBL detection.
引言
采用克拉维酸和第三代头孢菌素的常规表型方法检测超广谱β-内酰胺酶（ESBL），对于同时产生如AmpC等抑制剂耐药β-内酰胺酶的菌株并不理想。
目的
通过使用头孢吡肟和他唑巴坦增强对产AmpC菌株中ESBL的表型检测。
材料与方法
研究了2013年1月至2014年12月期间从住院患者尿液样本中分离得到的245株菌，其中大肠杆菌123株、克雷伯菌属87株、变形杆菌属20株、肠杆菌属9株和柠檬酸杆菌属6株。同时对这些菌株进行ESBL和AmpC产生情况的筛查。通过改良三维试验（MTDT）确认AmpC的产生。通过原始双纸片协同试验、表型纸片确证试验（PDCT）和改良双纸片协同试验（MDDST）确认ESBL的产生，并比较结果。
结果
在143株经筛查AmpC呈阳性的菌株中，通过改良三维试验确认113株（46.1%）产生AmpC。在192株经筛查ESBL呈阳性的菌株中，确认162株（66.1%）产生ESBL。双纸片协同试验（DDST）仅检测到134株（54.7%）ESBL，而改良双纸片协同试验（MDDST）额外检测到28株（11.4%）ESBL阳性菌株。表型纸片确证试验（PDCT）共检测到145株（59.2%）ESBL阳性菌株，其中头孢噻肟和头孢噻肟+克拉维酸检测到139株（56.7%），头孢他啶和头孢他啶+克拉维酸额外检测到6株。所有通过改良双纸片协同试验（MDDST）额外检测出的28株（11.4%）ESBL产生菌均显示三维试验阳性，即产AmpC菌。双纸片协同试验（DDST）在所有AmpC阳性菌株中均未检测到ESBL，而表型纸片确证试验（PDCT）在11株显示产AmpC的菌株中检测到ESBL。在改良双纸片协同试验（MDDST）中，头孢吡肟是在产AmpC情况下检测ESBL的最佳头孢菌素。它与阿莫西林-克拉维酸在11株（39.3%）菌株中显示协同作用，与哌拉西林-他唑巴坦在24株（85.7%）菌株中显示协同作用。第三代头孢菌素——头孢噻肟、头孢他啶和头孢泊肟在产AmpC菌株中无法检测到ESBL。
结论
将哌拉西林-他唑巴坦与头孢吡肟相结合的改良双纸片协同试验提高了ESBL检测的可能性。
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