Genotypic characteristics of Haemophilus influenzae isolates from pediatric pneumonia patients in Chengdu city, Sichuan, China

Tian, Guozhong; Zhang, Li; Li, Machao; Wang, Xiaolei; Zheng, Yuejie; Li, Xiaojing; Huang, Cheng; Li, Xuechun; Xie, Yongqiong; Xu, Li; Ren, Hao; Shao, Zhujun

doi:10.1007/s12275-009-0002-4

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…Overall, almost half of the strains identified by MLST in this population have not previously been described, and the majority of these do not appear to have any clonal phylogenetic relationships to other isolates. This finding of frequent novel STs in Hib is similar to other studies from the Netherlands (23), Poland (29), and China (33) where between 40 and 78% are novel STs. These findings are in contrast to those from a United Kingdom carriage study, more than a decade after vaccine implementation, where there were no new STs identified (19).…”

Section: Discussionsupporting

confidence: 91%

Haemophilus influenzae Type b Carriage and Novel Bacterial Population Structure among Children in Urban Kathmandu, Nepal

Williams¹,

Lewis²,

John³

et al. 2011

J Clin Microbiol

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Haemophilus influenzae type b (Hib) is a major cause of invasive bacterial infection in children that can be prevented by a vaccine, but there is still uncertainty about its relative importance in Asia. This study investigated the age-specific prevalence of Hib carriage and its molecular epidemiology in carriage and disease in Nepal. Oropharyngeal swabs were collected from children in Kathmandu, Nepal, from 3 different settings: a hospital outpatient department (OPD), schools, and children's homes. Hib was isolated using Hib antiserum agar plates, and serotyping was performed with latex agglutination. Hib isolates from children with invasive disease were obtained during active microbiological surveillance at Patan Hospital, Kathmandu, Nepal. Genotyping of disease and carriage isolates was undertaken using multilocus sequence typing (MLST). Swabs were taken from 2,195 children, including 1,311 children at an OPD, 647 children attending schools, and 237 children in homes. Overall, Hib was identified in 5.0% (110/2,195; 95% confidence interval [95% CI], 3.9% to 6.4%). MLST was performed on 108 Hib isolates from children carrying Hib isolates and 15 isolates from children with invasive disease. Thirty-one sequence types (STs) were identified, and 20 of these were novel STs. The most common ST isolates were sequence type 6 (ST6) and the novel ST722. There was marked heterogeneity among the STs from children with disease and children carrying Hib. STs identified from invasive infections were those commonly identified in carriage. This study provides evidence of Hib carriage among children in urban Nepal with genetically diverse strains prior to introduction of universal vaccination. The Hib carriage rate in Nepal was similar to the rates observed in other populations with documented high disease rates prior to vaccination, supporting implementation of Hib vaccine in Nepal in 2009.

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Section: Discussionsupporting

confidence: 91%

Haemophilus influenzae Type b Carriage and Novel Bacterial Population Structure among Children in Urban Kathmandu, Nepal

Williams¹,

Lewis²,

John³

et al. 2011

J Clin Microbiol

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“…In addition, our investigation reported a relative high genetic diversity among fluoroquinolone-resistant H. influenzae isolates. None of the STs published in Taiwan were found in our study, but ST422 and ST408 involved in our study were previously reported in Sichuan, China, where also discovered a series of diverse and novel sequence types as Taiwan [ 4 , 30 ]. The predominant epidemiological STs in China like ST486 and 480 were not found in our study.…”

Section: Discussionmentioning

confidence: 61%

Microbial virulence, molecular epidemiology and pathogenic factors of fluoroquinolone-resistant Haemophilus influenzae infections in Guangzhou, China

Chen

Wen

Feng

et al. 2018

Ann Clin Microbiol Antimicrob

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BackgroundFluoroquinolone-resistant Haemophilus influenzae (FRHI) has been reported worldwide but remain unclear in China.MethodsA total of 402 H. influenzae isolates collected from 2016 to 2017 were included. Antimicrobial susceptibility on 10 antibiotics was performed, and minimum inhibitory concentration of ciprofloxacin- and nalidixic acid-resistant strains were further determined by E-test strips, with risk factors also evaluated. Strains with resistance or reduced susceptibility to ciprofloxacin were subjected to sequencing of the quinolone resistance-determining regions (QRDR) and plasmid-mediated quinolone resistance genes by sequencing, with multi-locus sequence typing.Results2.2% of H. influenzae strains were non-susceptible (7/402, 1.7%) or susceptible (2/402, 0.5%) to ciprofloxacin but NAL-resistant by E-test, and multidrug resistance was more common in fluoroquinolones non-susceptible H. influenzae group (p = 0.000). Infection risk factors included invasive procedure (p = 0.011), catching cold/previous contact with someone who had a cold (p = 0.019), fluoroquinolones use during previous 3 months (p = 0.003). With none of mutations obtained in gyrB, parE and other plasmid-mediated quinolone resistance genes, 7 and 4 strains were found for Ser-84-Leu substitutions in gyrA and one amino acid substitution in the QRDR of gyrA linked with one amino acid substitution in the QRDR of parC, respectively. In addition, five sequence types (ST) were identified, with ST1719 firstly found.ConclusionsFor the first time, this study has reported the incidence, risk factors, molecular determinants on fluoroquinolones resistance and ST of FRHI strains in mainland China, representing the first evidence of mutation of gyrA and parC in China and the new ST1719 worldwide.

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“…High heterogeneity of NTHi or BLNAR was also revealed in other cities or countries. Tian et al typed 273 isolates of H influenzae from pediatric pneumonia patients in Chengdu, China, and 50 different STs (including 39 novel STs) were identified by multi‐locus sequence typing. No ST was correlated with isolates from Korea, which is geographically adjacent to China.…”

Section: Discussionmentioning

confidence: 99%

Widespread of non‐typeable Haemophilus influenzae with high genetic diversity after two decades use of Hib vaccine in China

Dong

Shi

Cheng

et al. 2019

Clinical Laboratory Analysis

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This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. AbstractBackground: The aim of this study was to analyze the microbiological characteristics of nasopharyngeal carriage Haemophilus influenzae isolates collected from children with respiratory infections in Beijing hospital and Youyang Hospital of China. Methods:The serotypes of all isolates were determined using latex agglutinated antisera (a-f). The minimum inhibitory concentrations (MICs) of 11 antibiotics were determined using E-test strips. For the beta-lactamase-negative ampicillin-resistant (BLNAR) isolates, ftsI gene was sequenced based on fragments amplified by PCR. STs of H influenzae isolates were determined by multi-locus sequence typing. Results:The overall carriage rate of H influenzae in the study population was 9.1% (362/3984). One hundred and ninety H influenzae isolates which were selected in our study were non-typeable (NTHi) and 44 (23.2%) of them were positive for β-lactamase.All isolates were susceptible to ceftriaxone and levofloxacin. Susceptibility rates to erythromycin and sulfamethoxazole-trimethoprim in Beijing were significantly higher than Youyang (P < .05). Thirty-six BLNAR isolates were identified. The MLST analysis showed 108 STs in 190 isolates, the most common of which were ST408 (11, 5.8%), ST914 (10, 5.3%), ST57 (9, 4.7%), and ST834 (6, 3.2%). Twelve STs were detected in both of the study sites, which covered 63 isolates. Conclusions:All isolates in the present study were NTHi, which suggested widespread of this type in China. The BLNAR isolates were detected more frequently than before. Because high genetic diversity of NTHi isolates of H influenzae exists worldwide, it is important to continuously monitor these bacteria in the future.

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Genotypic characteristics of Haemophilus influenzae isolates from pediatric pneumonia patients in Chengdu city, Sichuan, China

Cited by 4 publications

References 13 publications

Haemophilus influenzae Type b Carriage and Novel Bacterial Population Structure among Children in Urban Kathmandu, Nepal

Haemophilus influenzae Type b Carriage and Novel Bacterial Population Structure among Children in Urban Kathmandu, Nepal

Microbial virulence, molecular epidemiology and pathogenic factors of fluoroquinolone-resistant Haemophilus influenzae infections in Guangzhou, China

Widespread of non‐typeable Haemophilus influenzae with high genetic diversity after two decades use of Hib vaccine in China

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