Wang Sheng-Ru, Lo Wen-Tsung, Chou Chen-Ying, Chen Ying-Yan, Tsai Shu-Ying, Chu Mong-Ling, Wang Chih-Chien
Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
J Microbiol Immunol Infect. 2008 Feb;41(1):32-40.
Surveillance data of colonization by Haemophilus influenzae in Taiwan are lacking. This study aimed to define the nasopharyngeal carriage rate of H. influenzae among children younger than 5 years in northern Taiwan, and to determine the antibiotic susceptibility, serotype and the clonal relationship of these isolates.
Nasopharyngeal specimens were obtained from 511 healthy children younger than 5 years. All H. influenzae isolates were serotyped. The minimal inhibitory concentrations for various antibiotics were determined. Pulsed-field gel electrophoresis (PFGE) was used for clonal analysis.
Among 511 children, 269 (52.6%) had been vaccinated with at least one dose of H. influenzae type b (Hib) conjugate vaccine, 236 (46.2%) were unvaccinated and 6 (1.2%) had no vaccination records available. Twenty six H. influenzae strains were isolated. There were three Hib isolates and the others were nontypeable H. influenzae (NTHi). The carriage rate for Hib was 0.6% (3/511) and of NTHi was 5% (23/511). Three (1.27%) of the 236 unvaccinated children were carriers of Hib, whereas none of the 269 vaccinated children carried Hib. Two out of the three Hib isolates and 14 (60.9%) of 23 NTHi isolates were ampicillin-resistant. Multidrug resistance was found in 7 (26.9%) of the isolates. Among the isolates, 61.5% were beta-lactamase producers; there were no beta-lactamase-negative ampicillin-resistant isolates. The PFGE restriction patterns showed a wide diversity of genotypes.
There is very low nasopharyngeal carriage of Hib among children younger than 5 years in northern Taiwan. This may explain why the incidence of invasive Hib disease is also low in Taiwan. In addition, we found a high prevalence of beta-lactamase-positive ampicillin-resistant nasopharyngeal H. influenzae isolates.
台湾地区缺乏流感嗜血杆菌定植的监测数据。本研究旨在确定台湾北部5岁以下儿童中流感嗜血杆菌的鼻咽携带率，并确定这些分离株的抗生素敏感性、血清型及克隆关系。
从511名5岁以下健康儿童中获取鼻咽标本。对所有流感嗜血杆菌分离株进行血清分型。测定各种抗生素的最低抑菌浓度。采用脉冲场凝胶电泳（PFGE）进行克隆分析。
511名儿童中，269名（52.6%）至少接种过一剂b型流感嗜血杆菌（Hib）结合疫苗，236名（46.2%）未接种疫苗，6名（1.2%）无疫苗接种记录。分离出26株流感嗜血杆菌。有3株Hib分离株，其他为不可分型流感嗜血杆菌（NTHi）。Hib的携带率为0.6%（3/511），NTHi的携带率为5%（23/511）。236名未接种疫苗的儿童中有3名（1.27%）为Hib携带者，而269名接种疫苗的儿童中均无Hib携带者。3株Hib分离株中有2株、23株NTHi分离株中有14株（60.9%）对氨苄西林耐药。7株（26.9%）分离株存在多重耐药。在分离株中，61.5%为β-内酰胺酶产生菌；无β-内酰胺酶阴性且对氨苄西林耐药的分离株。PFGE限制性酶切图谱显示基因型具有广泛多样性。
台湾北部5岁以下儿童中Hib的鼻咽携带率极低。这可能解释了为何台湾侵袭性Hib疾病的发病率也较低。此外，我们发现β-内酰胺酶阳性且对氨苄西林耐药的鼻咽流感嗜血杆菌分离株的患病率较高。
