Tarasi A, D'Ambrosio F, Perrone G, Pantosti A
Istituto Superiore di Sanità, and Divisione di Clinica Medica III, Università La Sapienza, Rome, Italy.
Microb Drug Resist. 1998 Winter;4(4):301-6. doi: 10.1089/mdr.1998.4.301.
Haemophilus influenzae type b (Hib) still causes a large portion of meningitis in children less than 5 year old in Italy because vaccination against this agent has not been fully implemented in the country. We have studied 78 Hib strains and 4 nontypable H. influenzae (NTHi) isolated from the cerebrospinal fluid of subjects with meningitis for susceptibility to ampicillin, chloramphenicol, and ceftriaxone. The macrorestriction profiles of chromosomal DNA obtained by pulsed-field gel electrophoresis (PFGE) following digestion with SmaI and ApaI were also determined. All strains except one were equally susceptible to the antibiotics tested. One Hib strain, the only beta-lactamase producer, showed an intermediate susceptibility to ampicillin (MIC = 2 microg/ml), while maintaining full susceptibility to chloramphenicol and ceftriaxone. The analysis of the PFGE patterns showed that most of the Hib isolates, including the beta-lactamase-positive Hib strain, belonged to the same clone or to closely related subclones. For three PCR-confirmed NTHi isolates, we obtained completely different PFGE profiles. In conclusion, resistance to ampicillin still appears to be a rare finding in Hib strains causing meningitis in Italy; moreover, PFGE showed that the population structure of invasive Hib is essentially clonal.
在意大利，b型流感嗜血杆菌（Hib）仍是5岁以下儿童脑膜炎的主要病因，因为该国针对该病原体的疫苗接种尚未全面实施。我们研究了从脑膜炎患者脑脊液中分离出的78株Hib菌株和4株不可分型流感嗜血杆菌（NTHi）对氨苄西林、氯霉素和头孢曲松的敏感性。还测定了用SmaI和ApaI消化后通过脉冲场凝胶电泳（PFGE）获得的染色体DNA的宏观限制性图谱。除一株外，所有菌株对所测试的抗生素均同样敏感。一株Hib菌株是唯一产生β-内酰胺酶的菌株，对氨苄西林表现出中度敏感性（MIC = 2微克/毫升），而对氯霉素和头孢曲松仍保持完全敏感性。PFGE图谱分析表明，大多数Hib分离株，包括β-内酰胺酶阳性的Hib菌株，属于同一克隆或密切相关的亚克隆。对于3株经PCR确认的NTHi分离株，我们获得了完全不同的PFGE图谱。总之，在意大利引起脑膜炎的Hib菌株中，对氨苄西林耐药似乎仍然是罕见的发现；此外，PFGE表明侵袭性Hib的种群结构基本上是克隆性的。
