Ampicillin resistance and penicillin-binding proteins of Haemophilus influenzae.
Ampicillin resistance and penicillin-binding proteins of Haemophilus influenzae.
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流感嗜血杆菌的氨苄西林耐药性和青霉素结合蛋白。
DOI：
10.1099/00221287-132-10-2855
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Needham,CA
中科院分区：
文献类型：
--
作者：
Serfass,DA;Mendelman,PM;Chaffin,DO;Needham,CA
青霉素结合蛋白 (PBP) 改变与流感嗜血杆菌中非 β-内酰胺酶介导的氨苄西林耐药性相关。我们评估了几种氨苄西林敏感和耐药临床分离株的 PBP 谱。流感病毒确定所描述的改变发生的一致性，并记录该物种 PBP 谱的再现性。对于接种量为 100000 c.f.u 的敏感分离株，氨苄青霉素的 MIC 范围为 0.06 至 0.13 μg ml−1。当通过肉汤稀释测试时，当通过琼脂稀释测试时，所有四种分离株的浓度均为 0.5 μg ml−1。当通过肉汤稀释测试时，耐药分离株的 MIC 范围为 4 至 8 μg ml−1，当通过琼脂稀释测试时，MIC 范围为 1.5 至 16 μg ml−1。在细胞膜制剂和对指数生长期细胞进行的全细胞（体内）结合测定中，检测到至少八种分子量范围为 27 至 90 kDa 的不同 PBP。 PBP 变异性在氨苄西林敏感和耐药菌株中都很明显；然而，四种耐药菌株之间存在更大的变异性。 PBP 模式的差异包括 (1) 电泳迁移率、(2) 抗生素的结合能力和 (3) 两个耐药菌株中存在额外的 PBP。然而，所有耐药菌株的 PBP 5 (56 kDa) 均一致证明结合能力下降。青霉素和氨苄青霉素的饱和曲线表明 PBP 5 对抗生素的亲和力降低。这些结果表明 (a) 对于表现出变异性的物种（例如H），在解释 PBP 谱的变化时应小心谨慎。 (b) PBP 5 结合亲和力降低是与多种氨苄青霉素耐药野生型分离株相关的一致发现。
Penicillin-binding protein (PBP) alterations have been associated with non-β-lactamase-mediated ampicillin resistance inHaemophilus influenzae.We evaluated the PBP profiles of several ampicillin-susceptible and -resistant clinical isolates ofH. influenzaeto determine how consistently the described alterations occurred, and to document the reproducibility of the PBP profiles for this species. The MIC of ampicillin ranged from 0.06 to 0.13 μg ml−1for the susceptible isolates at an inoculum of 100000 c.f.u. when tested by broth dilution, and was 0.5 μg ml−1for all four isolates when tested by agar dilution. The MIC for the resistant isolates ranged from 4 to 8 μg ml−1when tested by broth dilution, and from 1.5 to 16 μg ml−1when tested by agar dilution. At least eight distinct PBPs with molecular masses ranging from 27 to 90 kDa were detected both in cell membrane preparations and whole cell (in vivo) binding assays done on cells in the exponential growth phase. PBP variability was evident both in the ampicillin-susceptible and -resistant isolates; however, much greater variability existed within the four resistant strains. The differences in PBP patterns included (1) electrophoretic mobility, (2) binding capacity for the antibiotic and (3) the presence of additional PBPs in two of the resistant isolates. However, decreased binding capacity was consistently demonstrated in PBP 5 (56 kDa) of all of the resistant isolates. Saturation curves with both penicillin and ampicillin indicated that PBP 5 had decreased affinity for the antibiotics. These results suggest (a) that care should be taken in interpreting changes in PBP profiles for species that demonstrate variability such asH. influenzae, and (b) that the decreased binding affinity of PBP 5 is a consistent finding associated with multiple ampicillin-resistant wild-type isolates.