Tristram Stephen G, Bozdogan Bülent, Appelbaum Peter C
School of Human Life Sciences, University of Tasmania, Launceston, Tasmania 7250, Australia.
J Antimicrob Chemother. 2005 Apr;55(4):570-3. doi: 10.1093/jac/dki036. Epub 2005 Feb 22.
To establish a suitable screening test for the detection of extended-spectrum beta-lactamases (ESBLs) in Haemophilus influenzae.
Double disc diffusion tests using cephalosporin discs adjacent to an amoxicillin/clavulanate 3 microg disc, prediffusion tests, where an amoxicillin/clavulanate 3 microg disc was prediffused before being replaced with a cephalosporin disc, and combination cephalosporin/clavulanate discs were used to screen recombinant H. influenzae expressing cloned ESBLs. Methods initially determined to be suitable were validated by testing a range of clinical strains.
Enhanced zones around cephalosporin discs due to synergy with an adjacent amoxicillin/clavulanate disc were not reliably demonstrated with the recombinant H. influenzae strains expressing ESBLs. Cefotaxime 5 microg or 30 microg and cefpodoxime 10 microg discs prediffused with an amoxicillin/clavulanate 3 microg disc, and cefotaxime 30 microg/clavulanate 10 microg and cefpodoxime 10 microg/clavulanate 1 microg combination discs all gave zone sizes > or = 5 mm greater than the corresponding plain disc for all recombinant ESBL-producing strains. None of the clinical strains gave enhanced zones.
Cefotaxime 5 or 30 microg or cefpodoxime 10 microg discs prediffused with an amoxicillin/clavulanate 3 microg disc, or cefotaxime 30 microg/clavulanate 10 microg and cefpodoxime 10 microg/clavulanate 1 mug combination discs are all suitable for screening H. influenzae isolates for the presence of ESBLs. ESBL-producing strains should show an increase in zone diameter of > or = 5 mm compared with the corresponding plain cephalosporin disc.
建立一种适用于检测流感嗜血杆菌中广谱β-内酰胺酶（ESBLs）的筛选试验。
使用与3μg阿莫西林/克拉维酸盘相邻的头孢菌素盘进行双纸片扩散试验、预扩散试验（将3μg阿莫西林/克拉维酸盘预扩散后再替换为头孢菌素盘）以及头孢菌素/克拉维酸联合纸片，用于筛选表达克隆ESBLs的重组流感嗜血杆菌。通过检测一系列临床菌株对初步确定合适的方法进行验证。
对于表达ESBLs的重组流感嗜血杆菌菌株，未可靠显示出因与相邻阿莫西林/克拉维酸盘协同作用而导致头孢菌素盘周围抑菌圈增大。用3μg阿莫西林/克拉维酸盘预扩散的5μg或30μg头孢噻肟盘、10μg头孢泊肟盘，以及30μg头孢噻肟/10μg克拉维酸盘和10μg头孢泊肟/1μg克拉维酸联合纸片，对于所有产重组ESBL的菌株，抑菌圈大小均比相应的普通纸片大≥5mm。所有临床菌株均未出现抑菌圈增大的情况。
用3μg阿莫西林/克拉维酸盘预扩散的5μg或30μg头孢噻肟盘、10μg头孢泊肟盘，或30μg头孢噻肟/10μg克拉维酸盘和10μg头孢泊肟/1μg克拉维酸联合纸片均适用于筛选流感嗜血杆菌分离株中是否存在ESBLs。产ESBL的菌株与相应的普通头孢菌素纸片相比，抑菌圈直径应增大≥5mm。
