Diversity and sharing of Haemophilus influenzae strains colonizing healthy children attending day-care centers

Farjo, Rand S.; Foxman, Betsy; Patel, Mayuri; Zhang, Lixin; Pettigrew, Melinda M.; McCoy, Sandra I.; Marrs, Carl F.; Gilsdorf, Janet R.

doi:10.1097/01.inf.0000106981.89572.d1

Cited by 73 publications

(76 citation statements)

References 32 publications

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“…Colonization of potential respiratory pathogens in the URT is very common in healthy children (Farjo et al, 2004). Our longitudinal carriage study indicated that the carriage of Strep.…”

Section: Association Between Colonization Of the Four Bacteriamentioning

confidence: 97%

“…Most carriage studies have focused on individually evaluating colonization by a single bacterium (O'Brien et al, 2003;Farjo et al, 2004;Greenberg et al, 2004). Recently, some carriage studies have reported the cooccurrence of a number of bacteria and suggested direct interactions such as interference or competition between the various bacterial species in the URT (Jacoby et al, 2007;Pettigrew et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Nasal colonization by four potential respiratory bacteria in healthy children attending kindergarten or elementary school in Seoul, Korea

Bae

Lee

et al. 2012

Journal of Medical Microbiology

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A longitudinal analysis was carried out of the colonization by four potential respiratory pathogens -Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus -in 165 healthy children (aged 3-7 years) attending three kindergartens and 417 healthy children (aged 7-10 years) attending an elementary school in Seoul, Korea, by four consecutive examinations over 1 year. The prevalence of nasal carriers of one or more of four bacteria was found to be higher in younger children (¡7 years) (mean 68.6 %) than that in older children (mean 46.8 %). The mean rates of nasal carriage of Strep. pneumoniae, H. influenzae, M. catarrhalis and Staph. aureus were 16.8, 18.9, 20.2 and 18.2 %, respectively. Colonization by Strep. pneumoniae, H. influenzae and M. catarrhalis was higher in pre-school children (28.6, 32.4 and 35.0 %, respectively) than in school children (12.2, 13.6 and 14.3 %, respectively). Carriage trends differed with age, with Strep. pneumoniae, H. influenzae and M. catarrhalis colonization decreasing with age but Staph. aureus colonization increasing. Positive associations of co-occurrence between Strep. pneumoniae, H. influenzae and M. catarrhalis were evident, with a significant negative association evident between Staph. aureus and the other three bacteria. A better understanding of the colonization and interaction of potential respiratory pathogens may be important for predicting changes in bacterial ecology and for designing control strategies that target bacterial colonization in upper respiratory tract infections.

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“…Colonization of potential respiratory pathogens in the URT is very common in healthy children (Farjo et al, 2004). Our longitudinal carriage study indicated that the carriage of Strep.…”

Section: Association Between Colonization Of the Four Bacteriamentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Nasal colonization by four potential respiratory bacteria in healthy children attending kindergarten or elementary school in Seoul, Korea

Bae

Lee

et al. 2012

Journal of Medical Microbiology

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“…Often disregarded as an oral contaminant, NTHi commonly colonizes the upper respiratory tract (36,37). However, this common human upper respiratory tract commensal is also a significant pathogen in the lower respiratory tract of patients with CF (11-13, 15, 38-40).…”

Section: Nthi In Early Cf Lung Diseasementioning

confidence: 99%

Haemophilus influenzaeForms Biofilms on Airway Epithelia

Starner

Zhang

Kim

et al. 2006

Am J Respir Crit Care Med

188

155

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“…Historically, H. influenzae strains lacking a capsule were detected by their failure to react with antibodies directed against the six immunologically distinct capsular polysaccharides and were designated nontypeable, i.e., serotype negative, H. influenzae (NTHI) (33). Nontypeable strains predominate among commensal organisms (9,29) and those causing respiratory infections such as acute otitis media, sinusitis, or bronchitis, while serotypeable strains are isolated more often from clinical samples of patients with invasive infections such as bacteremia, meningitis, facial cellulitis, and septic arthritis. In addition, multilocus sequence typing has shown that NTHI strains are genetically widely variable, while serotypeable strains are more clonal (25).…”

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confidence: 99%

Use of bexB To Detect the Capsule Locus in Haemophilus influenzae

et al. 2011

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Haemophilus influenzae strains are classified as typeable or nontypeable H. influenzae (NTHI) based upon the presence or absence of capsule. In addition to serotyping, which is subject to false-positive results, typeable strains can be identified through the detection of the capsular export gene bexA and one of six capsule-specific genes, but this method is resource intensive, especially in characterizing large numbers of strains. To address these challenges, we developed a bexB-based method to differentiate true NTHI strains from typeable strains. We validated a PCR-based method to detect bexB in 10 strains whose capsule status was well defined. Among 40 strains that were previously serotype positive in clinical microbiology laboratories, 5 lacked bexA, bexB, and capsule type-specific genes by PCR analysis and thus likely represent false-positive serotyping results. Among 94 additional otitis media, commensal, and serotype b-negative invasive strains, 85 were bexA and bexB negative and 9 contained either a complete or partial capsule locus, i.e., 8 were bexA and bexB positive and 1 was bexA negative but bexB positive. Finally, we adapted the method for use in a high-throughput DNA hybridizationbased microarray method, which showed 98.75 and 97.5% concordance to the PCR methods for bexA and bexB, respectively. In addition, bexB showed 84% or greater nucleotide identity among strains containing the capsule locus. In this study, we demonstrate that bexB is a reliable proxy for the capsule locus and that its detection provides a simple and reliable method for differentiating strains that lack the entire capsule locus from those containing a partial or complete capsule locus.

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Diversity and sharing of Haemophilus influenzae strains colonizing healthy children attending day-care centers

Abstract: The degree of sharing of H. influenzae among children in this study suggests transmission of these potentially pathogenic microorganisms in day-care centers.

Cited by 73 publications

References 32 publications

Nasal colonization by four potential respiratory bacteria in healthy children attending kindergarten or elementary school in Seoul, Korea

Nasal colonization by four potential respiratory bacteria in healthy children attending kindergarten or elementary school in Seoul, Korea

Haemophilus influenzaeForms Biofilms on Airway Epithelia

Use of bexB To Detect the Capsule Locus in Haemophilus influenzae

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