Nasopharyngeal Haemophilus influenzae Carriage in Japanese Children Attending Day-Care Centers

Abstract

We conducted a prospective bacteriological survey to investigate antibiotic resistance-related genetic characteristics and the turnover of nasopharyngeal Haemophilus influenzae carriage in healthy children in day-care centers (DCCs). A total of 363 nasopharyngeal mucus samples were collected from children aged 0 to 6 years attending two DCCs in the summer of 2004 (n ‫؍‬ 184) and the following winter (n ‫؍‬ 179). We obtained 172 H. influenzae isolates and analyzed them by antimicrobial susceptibility testing, PCR for bla TEM-1 and the penicillin-binding protein (PBP) gene, and pulsed-field gel electrophoresis (PFGE). The overall carriage rate was 47.4% (172/363), and 37.2% of the isolates (64/172) were ampicillin (AMP) resistant. All the resistant isolates had a PBP mutation(s), while only three isolates had TEM-1. The carriage rate was significantly higher in the winter than in the summer (56.4% and 38.6%, respectively), owing to the increase in the numbers of AMP-susceptible H. influenzae isolates in the winter. Children aged <3 years showed a higher rate of carriage of H. influenzae isolates with an AMP resistance gene(s) than those aged >4 years (21.9% and 12.6%, respectively). Forty-two strains with different PFGE patterns were obtained from among the 172 isolates. Only five strains were observed in both seasons. None of the strains isolated in the summer was isolated from the same carrier in the winter. Twenty-seven strains (64.3%) were isolated from two or more children, and 25 of these were each isolated from children belonging to the same DCC. These results indicate the spread of H. influenzae, particularly those with a PBP mutation(s), and the highly vigorous genetic turnover and substantial horizontal transmission of this pathogen in healthy children attending DCCs in Japan.

Oropharyngeal Colonization by NontypeableHaemophilus influenzaeAmong Healthy Children Attending Day Care Centers

“…In our current work, the rate of ampicillin resistance due to b-lactamase production was very low (24% in 2005 and 13% in 2004) compared to other worldwide studies that ranged between 35% and 45% of the H. influenzae isolates. 2,6,7,12,19,21 Despite this low prevalence, ampicillin resistance increased significantly in the second year where we observed a twofold increment in the b-lactamaseproducing strains. The isolate characterization was completed with a determination of the PBP3 mutations associated to ampicillin resistance.…”

“…16 Although NTHi is considered less virulent than Hib, it can be responsible for severe diseases, especially among children with previous comorbidities. 11 Several studies have been performed to establish the H. influenzae carriage rate after vaccine introduction, 2,7,10,[12][13][14][19][20][21] although to our knowledge, no studies have been reported from Spain. Longitudinal studies performed on one or two selected DCCs give information about the dynamics of colonization, but fail to give an overall view of the situation in similar centers of the same geographical area.…”

Correlation of Bacterial Colonization Status between Mother and Child: the Generation R Study

“…In case of nontypeable strains (ST398), PFGE was performed with Srf9I (20 U), a neoschizomer of SmaI (21). H. influenzae strains were genotyped by PFGE as described previously by Hashida et al (11). PFGE data were inspected visually for banding pattern identity.…”

The continuing role ofHaemophilus influenzaetype b carriage surveillance as a mechanism for early detection of invasive disease activity

“…66 Results from a northern Indian study, a of humans and is transmitted via respiratory secretions. 25 Most commonly commensal of the nasopharynx, especially in young children, 24,[26][27][28][29][30][31][32][33][34][35][36] although it is also found in the oropharynx. 19,[37][38][39][40][41] The detection of Hib is determined by microbiological culture.…”

“…The Phadebact ® Hemophilus test (Bactus, Sweden) is a reagent test that differentiates capsular types, as described in reference 44 and 45, a more expensive alternative for serotypes, is the use of Protein Chain Reaction (PCR) followed by Pulsed-field gel electrophoresis (PFGE). 29 Methodology for isolation can be selected by nations or regional centers according to resource allocation, largely driven by budget and availability.…”