Analysis of isolates recovered from multiple sites of the nasopharynx of children colonized by nontypeableHaemophilus influenzae

Bernstein, Joel; Dryja, Diane; Yuskiw, Norine; Murphy, Timothy F.

doi:10.1007/bf01709258

Cited by 11 publications

(12 citation statements)

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“…Forty-four percent of the children were colonized on one or more occasions, and the acquisition rate was greatest in the first year. Colonization mainly involves a dominant strain which can be followed by a series of other strains (1,9,15,24). The level of carriage varies according to different factors, i.e., age, siblings, and living conditions.…”

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confidence: 99%

Haemophilus influenzae Carriage in Children Attending French Day Care Centers: a Molecular Epidemiological Study

et al. 2003

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The nasopharyngeal Haemophilus influenzae flora of healthy children under the age of 3 years attending day care centers in three distinct French geographic areas was analyzed by sampling during two periods, spring 1999 (May and June) and fall 1999 (November and December). The average carrier rate among 1,683 children was 40.9%. The prevalence of capsulated H. influenzae carriers was 0.4% for type f and 0.6% for type e. No type b strains were found among these children, of whom 98.5% had received one or more doses of anti-Haemophilus b vaccine. Among the strains, 44.5% were TEM-type beta-lactamase producers and nine (1.3%) were betalactamase-negative ampicillin-resistant strains. Pulsed-field gel electrophoresis restriction patterns showed a large diversity with 366 SmaI patterns from 663 strains. Among the strains isolated during a given period, 33% were isolated simultaneously in more than one area. In each area, depending on the sampling period, 68 to 72% of the strains had new pulsotypes and persistence of 28 to 32% of the strains was noted. For the 297 beta-lactamase-producing strains, 194 patterns were found. The genomic diversity of these strains was comparable to that of the whole set of strains and does not suggest a clonal diffusion. Among the beta-lactamaseproducing strains isolated in November and December, depending on the area, 66 to 73% had new pulsotypes with persistence of only 27 to 33% of the strains. In any given geographic area, colonization by H. influenzae appears to be a dynamic process involving a high degree of genomic heterogeneity among the noncapsulated colonizing strains.Haemophilus influenzae is one of the main bacterial species causing infection in children. Encapsulated strains are responsible for a variety of invasive diseases, the most frequent being meningitis, but epiglottitis, arthritis, pneumonia, and cellulitis also occur (36). These invasive diseases have decreased sharply since the generalization of anti-Haemophilus b (anti-Hib) vaccination (22, 37). Noncapsulated strains frequently cause acute otitis media in children (6,20,29,32). H. influenzae is often part of the nasopharynx flora and is frequently found in the upper respiratory tract of healthy children, with reported carriage rates of up to 60% (12,17,23,32).In the study of Faden et al. (9), 200 children were monitored from birth through to 2 years of age to determine the nasopharyngeal colonization pattern of nontypeable H. influenzae. Forty-four percent of the children were colonized on one or more occasions, and the acquisition rate was greatest in the first year. Colonization mainly involves a dominant strain which can be followed by a series of other strains (1,9,15,24). The level of carriage varies according to different factors, i.e., age, siblings, and living conditions. All of these factors can also have repercussions on the carriage of strains resistant to antibiotics or encapsulated type b strains. Anti-Hib vaccination has led to a sharp drop in the carriage of encapsulated type b strains (33).The turnove...

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confidence: 99%

Haemophilus influenzae Carriage in Children Attending French Day Care Centers: a Molecular Epidemiological Study

et al. 2003

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“…Analysis of isolates recovered from 6 different sites in the nasopharynx of 5 children undergoing adenoidectomy revealed that each child harbored a single strain of H. influenzae in the nasopharynx [8]. In contrast, analysis of isolates from the nasopharynx of Australian aboriginal children in a population that is heavily colonized by H. influenzae showed that most children harbored multiple strains [14,15].…”

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confidence: 95%

“…Each isolate of H. influenzae grown from a single colony from the original plate was analyzed by polymerase chain reaction (PCR)-based genomic DNA typing, as described elsewhere [7,8]. In brief, 3 colonies were suspended in 0.1 mL of sterile water and centrifuged at 14,000 g for 5 min.…”

Section: Methodsmentioning

confidence: 99%

Simultaneous Respiratory Tract Colonization by Multiple Strains of NontypeableHaemophilus influenzaein Chronic Obstructive Pulmonary Disease: Implications for Antibiotic Therapy

et al. 1999

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Nontypeable Haemophilus influenzae often causes exacerbations of chronic obstructive pulmonary disease (COPD), and these exacerbations are frequently treated with oral antibiotics. The goals of this study were to determine the frequency of the simultaneous presence of multiple strains of H. influenzae in sputum and to measure the MICs of antibiotics for the isolates. In a prospective study, adults with COPD were seen monthly. Sputum cultures were obtained, and individual colonies were subjected to genomic DNA typing and MIC determinations. Multiple strains of H. influenzae were present simultaneously in the sputum of 26.3% of adults with COPD. In 64.5% of these, MICs of >/=1 antibiotic varied by >/=4-fold among the strains. Therefore, multiple strains of H. influenzae are frequently present simultaneously in the sputum of adults with COPD, and the antimicrobial susceptibility of different strains in the same sputum sometimes differs.

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“…Many commensal strains of pathogens that are present in the nasopharynx have potential pathogenicity [33]. The nasopharynx of children with AOM could have been colonized by an aggressive strain that replaced the benign commensal strain and progressed to causing infections in the middle ear.…”

Section: Discussionmentioning

confidence: 99%

Genotyping of <i>Streptococcus pneumoniae</i> and <i>Haemophilus influenzae</i> Isolated from Paired Middle Ear Fluid and Nasopharynx by Pulsed-Field Gel Electrophoresis

Hotomi

Yamanaka²,

Billal³

et al. 2004

ORL

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Twenty-eight isolates of Streptococcus pneumoniae and 30 isolates of Haemophilus influenzae from paired nasopharynx and middle ear fluids of 21 children with acute otitis media (AOM) were evaluated to determine genotypes by polymerase chain reaction and pulsed-field gel electrophoresis (PFGE). Among the 28 isolates of S. pneumonaie, 21 isolates (75.0%) possessed mutations in the pbp1a,pbp2x, and pbp2b genes, and 7 isolates (25%) had mutations in the pbp2x gene. Nineteen isolates (67.9%) expressed the mefE gene, and 5 isolates (17.9%) possessed the ermB gene. Among the 30 isolates of H. influenzae, 5 isolates (16.7%) had mutations in pbp3 genes, 3 isolates (10.0%) produced β-lactamase, and 2 (6.7%) isolates possessed mutations both in the pbp3 gene and the β-lactamase gene. Ten out of the 14 pairs (71.4%) of the restriction fragment patterns of S. pneumoniae from paired nasopharynx and middle ear fluids were indistinguishable following PFGE analysis. The same patterns were identified among 5 children of unrelated families. The restriction fragment patterns of H. influenzae isolated by PFGE were also indistinguishable in 13 out of the 15 pairs (86.7%) of nasopharynx and middle ear fluids. The genetic similarity between nasopharyngeal and middle ear isolates suggests that the causative bacteria migrate from the nasopharynx into the middle ear cavity via the Eustachian tube. Some resistant strains might be prevalent. In children with AOM, the nasopharynx could have been colonized by a virulent strain of bacteria that replaced the benign, commensal bacteria and then progressed to the middle ear, where they caused AOM.

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Analysis of isolates recovered from multiple sites of the nasopharynx of children colonized by nontypeableHaemophilus influenzae

Cited by 11 publications

References 11 publications

Haemophilus influenzae Carriage in Children Attending French Day Care Centers: a Molecular Epidemiological Study

Haemophilus influenzae Carriage in Children Attending French Day Care Centers: a Molecular Epidemiological Study

Simultaneous Respiratory Tract Colonization by Multiple Strains of NontypeableHaemophilus influenzaein Chronic Obstructive Pulmonary Disease: Implications for Antibiotic Therapy

Genotyping of <i>Streptococcus pneumoniae</i> and <i>Haemophilus influenzae</i> Isolated from Paired Middle Ear Fluid and Nasopharynx by Pulsed-Field Gel Electrophoresis

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