Bakthavatchalu Sasirekha, Shakthivel Uma, Mishra Tannu
Department of Microbiology, Centre for Post Graduate Studies, Jain University, Bangalore, Karnataka--560 011, India.
Pan Afr Med J. 2013;14:28. doi: 10.11604/pamj.2013.14.28.1347. Epub 2013 Jan 20.
The occurrence of multiple β-lactamases among bacteria only limits the therapeutic options but also poses a challenge. A study using boronic acid (BA), an AmpC enzyme inhibitor, was designed to detect the combined expression of AmpC β-lactamases and extended-spectrum β-lactamases (ESBLs) in bacterial isolates further different phenotypic methods are compared to detect ESBL and AmpC.
A total of 259 clinical isolates of Enterobacteriaceae were isolated and screened for ESBL production by (i) CLSI double-disk diffusion method (ii) cefepime- clavulanic acid method (iii) boronic disk potentiation method. AmpC production was detected using cefoxitin alone and in combination with boronic acid and confirmation was done by three dimensional disk methods. Isolates were also subjected to detailed antibiotic susceptibility test.
Among 259 isolates, 20.46% were coproducers of ESBL and AmpC, 26.45% were ESBL and 5.40% were AmpC. All of the 53 AmpC and ESBL coproducers were accurately detected by boronic acid disk potentiation method.
The BA disk test using Clinical and Laboratory Standards Institute methodology is simple and very efficient method that accurately detects the isolates that harbor both AmpCs and ESBLs.
细菌中多种β-内酰胺酶的出现不仅限制了治疗选择，还带来了挑战。一项使用硼酸（一种AmpC酶抑制剂）的研究旨在进一步检测细菌分离株中AmpCβ-内酰胺酶和超广谱β-内酰胺酶（ESBLs）的联合表达，并比较不同的表型方法来检测ESBL和AmpC。
共分离出259株肠杆菌科临床分离株，并通过以下方法筛选ESBL的产生：（i）CLSI双纸片扩散法；（ii）头孢吡肟-克拉维酸法；（iii）硼酸纸片增强法。单独使用头孢西丁以及与硼酸联合使用来检测AmpC的产生，并通过三维纸片法进行确认。对分离株还进行了详细的药敏试验。
在259株分离株中，20.46%为ESBL和AmpC的共同生产者，26.45%为ESBL生产者，5.40%为AmpC生产者。所有53株AmpC和ESBL共同生产者均通过硼酸纸片增强法准确检测到。
使用临床和实验室标准协会方法的硼酸纸片试验是一种简单且非常有效的方法，能够准确检测出同时携带AmpC和ESBL的分离株。
