Touati A, Achour W, Ben Hassen A
Laboratory unit, Bone Marrow Transplant Centre, rue Djebel-Lakdhar, Bab-Saadoun, 1006 Tunis, Tunisia.
Pathol Biol (Paris). 2009 Jul;57(5):353-7. doi: 10.1016/j.patbio.2007.09.016. Epub 2008 Jan 4.
The aim of this study was to determine the overall percentage of beta-lactams susceptibility, beta-lactamase production, penicillin binding protein (PBP) modification and serotypes of colonizing Haemophilus influenzae strains.
A total of 50 isolates of colonized H. influenzae, isolated from neutropenic patients. The prevalence of beta-lactams resistance and beta-lactamase production were recorded for each strains using E-test strips and chromogenic cephalosporin test, then were determined their resistance genes (bla(TEM) and bla(ROB)) by PCR as well as their capsular types by standard slide agglutination serotyping (SAST) and capsular genes amplification.
Thirty-two percent of the 50 strains were amoxicillin resistant, among these, 20% were resistant by beta-lactamase production, and they produced all type TEM beta-lactamase. Four percent of the isolates had PBP modification and three strains (6%) associated the two resistance mechanisms. Slide agglutination serotyping showed that 95.8% of the strains were unencapsulated, and 4.1% were of serogroup b. The result was confirmed by PCR capsular typing.
By the light of these results, our findings suggest that it becomes important to follow the evolution of the resistance background of our strains, and that the majority of colonizing H. influenzae strains isolated in our center are unencapsulated.
本研究旨在确定定植的流感嗜血杆菌菌株的β-内酰胺类药物敏感性、β-内酰胺酶产生情况、青霉素结合蛋白（PBP）修饰情况及血清型的总体百分比。
从嗜中性粒细胞减少症患者中分离出50株定植的流感嗜血杆菌。使用E-test试纸条和显色头孢菌素试验记录每株菌株的β-内酰胺类药物耐药性和β-内酰胺酶产生情况，然后通过PCR测定其耐药基因（bla(TEM)和bla(ROB)），并通过标准玻片凝集血清分型（SAST）和荚膜基因扩增确定其荚膜类型。
50株菌株中有32%对阿莫西林耐药，其中20%通过产生β-内酰胺酶耐药，且均产生TEM型β-内酰胺酶。4%的分离株有PBP修饰，3株（6%）存在两种耐药机制。玻片凝集血清分型显示95.8%的菌株无荚膜，4.1%为b血清群。PCR荚膜分型证实了该结果。
根据这些结果，我们的研究结果表明，跟踪我们菌株耐药背景的演变很重要，并且我们中心分离的大多数定植流感嗜血杆菌菌株无荚膜。
