<i>Haemophilus haemolyticus:</i>A Human Respiratory Tract Commensal to Be Distinguished from<i>Haemophilus influenzae</i>

Murphy, Timothy F.; Brauer, Aimee L.; Sethi, Sanjay; Kilian, Mogens; Cai, Xueya; Lesse, Alan J.

doi:10.1086/509824

Cited by 203 publications

(278 citation statements)

References 46 publications

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“…Only one colony of NTHi from each sample was cultured and stored at 280 uC for further experiments. An isolate was further identified as NTHi as described by Murphy et al (2007), including ompP6 sequencing to distinguish NTHi from Haemophilus haemolyticus. b-Lactamase testing was performed on all NTHi isolates by Cefinase disc test.…”

Section: Methodsmentioning

confidence: 99%

Phylogenetic relatedness and diversity of non-typable Haemophilus influenzae in the nasopharynx and middle ear fluid of children with acute otitis media

Kaur

Chang

et al. 2011

Journal of Medical Microbiology

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The phylogenetic relationships of non-typable Haemophilus influenzae (NTHi) strains prospectively isolated from healthy children and children with acute otitis media (AOM) were analysed using multilocus sequence typing (MLST). A total of 165 NTHi isolates were collected over a 3.5 year time frame during 2006 through 2009. The strains were tested for b-lactamase production; 28.5 % were positive. Seventy different NTHi sequence types (STs) were identified of which 29 (41.4 %) were novel. NTHi strains did not show any phylogenetic grouping or clustering among asymptomatic colonizing strains or strains that caused AOM, or based on b-lactamase enzyme production. Evaluation of triplets and other siblings over time demonstrated relatively frequent genetic exchanges in NTHi isolates in vivo in a short time frame and subsequent transfer among children in a family. Comparison of the MLST STs isolated at different time points showed that in~85 % of the nasopharynx (NP) colonizations, NTHi strains cleared from the host within 3 months, that sequential colonization in the same child involved different strains in all cases except one, and that NP and middle ear isolates were identical STs in 84 % of cases. In this first study of its type to our knowledge, we could not identify predominant MLST types among strains colonizing the NP versus those causing AOM or expressing a b-lactamase enzyme conferring penicillin resistance in children. INTRODUCTIONNon-typable Haemophilus influenzae (NTHi) is an important human-specific pathogen colonizing the nasopharynx (NP) of the upper respiratory tract (Faden et al., 1995; Murphy et al., 2009). NTHi strains are rarely associated with invasive disease in children, but they are associated with respiratory tract infections in both children and adults (Murphy, 2003;Kyd & Cripps, 1999). NP colonization with NTHi is an important risk factor for developing disease (Faden et al., 1997). Children frequently NP-colonized by NTHi are more likely to develop acute otitis media (AOM) than less frequently colonized children (Faden et al., 1997; Harabuchi et al., 1994). Simultaneous detection of multiple isolates of NTHi from the same sample has been reported among aboriginal children with otitis media (Smith-Vaughan et al., 1996), among otitis-prone children in day care centres (St Sauver et al., 2000) and in cystic fibrosis patients (Bandi et al., 2001; Murphy et al., 1999), which may result from inadequate clearance of colonizing bacteria, exposure to multiple circulating strains or in vivo genetic recombinations in a specific host. It is not known whether NTHi isolates that express b-lactamases (responsible for resistance to b-lactam antibiotics such as penicillins, cephamycins and carbapenems) are phylogenetically related. Various studies of Streptococcus pneumoniae have shown phylogenetic relationships among antibiotic-resistant strains (Beall et al., 2006;Hanage et al., 2009;Porat et al., 2004;Xu et al., 2009). In this study, we explored whether or not NTHi shows genetic relatedness in relation...

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Section: Methodsmentioning

confidence: 99%

Phylogenetic relatedness and diversity of non-typable Haemophilus influenzae in the nasopharynx and middle ear fluid of children with acute otitis media

Kaur

Chang

et al. 2011

Journal of Medical Microbiology

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“…A proportion of the isolates initially identified as variant H. influenzae in the ongoing COPD study previously referred to, were later characterised as non-haemolytic Haemophilus haemolyticus [13]. A re-examination of the relationship between H. influenzae strain acquisition and exacerbation after excluding the H. haemolyticus strains showed a four-fold increase in the incidence of exacerbation associated with such acquisition [13].…”

Section: Mechanisms Of Bacterial Pathogenesis In Copdmentioning

confidence: 99%

Infection as a comorbidity of COPD

Sethi

2010

European Respiratory Journal

203

166

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The normal lung has several defence mechanisms to deal with microorganisms. Lower respiratory infections in the absence of lung disease are therefore relatively infrequent as compared with upper respiratory tract infections in healthy adults. In the setting of chronic obstructive pulmonary disease (COPD), lower respiratory tract infections, both acute and chronic, occur with increased frequency. As these infections contribute considerably to the clinical course of the patient with COPD, they constitute a significant comorbidity in COPD. Recurrent acute infections by bacterial and/or viral pathogens are now clearly linked with the occurrence of exacerbations of COPD. In addition, the occurrence of pneumonia in COPD has received considerable recent attention as it appears to be increased by the use of inhaled corticosteroids. The role of chronic infection in the pathogenesis of COPD is an active area of research with several different types of pathogens potentially implicated. Additionally, COPD patients with HIV infection have a more rapidly progressive decline in lung function than non-HIV-infected patients. Enhanced understanding of the host-pathogen interaction is needed to better prevent and treat respiratory tract infection in COPD.

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“…The mechanisms underlying the association between NT H. influenzae acquisition and exacerbations are poorly understood (5,18). In a prospective study of COPD patients, Murphy et al (19) noted that selected sputum isolates of apparent NT H. influenzae had an altered phenotype, including slower growth in broth culture and a tendency to form aggregates. On the basis of genetic analyses (ribosomal DNA sequencing, multilocus sequence typing, DNA-DNA hybridization, and sequencing of the gene encoding the outer membrane protein P6), the variant isolates were proven to be H. haemolyticus, a bacterium that had not previously been considered a constituent of the respiratory tract flora.…”

Section: Infection With Nontypeable (Nt)mentioning

confidence: 99%

“…On the basis of genetic analyses (ribosomal DNA sequencing, multilocus sequence typing, DNA-DNA hybridization, and sequencing of the gene encoding the outer membrane protein P6), the variant isolates were proven to be H. haemolyticus, a bacterium that had not previously been considered a constituent of the respiratory tract flora. By conventional criteria, 102 of 258 (39.5%) and 12 of 44 (27.3%) sputum and nasopharyngeal isolates, respectively, had been misclassified (19). In routine analysis in the clinical laboratory, hemolysis on blood agar is the only characteristic that distinguishes NT H. influenzae from H. haemolyticus (4,9,10).…”

Section: Infection With Nontypeable (Nt)mentioning

confidence: 99%

“…Nevertheless, while we await appropriate developments for simple rapid tests in the field of SOD assays, the procedures described herein can clearly distinguish H. haemolyticus from NT H. influenzae. A test that combines monoclonal antibodies HD1 (which recognized the CuZnSOD of H. haemolyticus but not that of NT H. influenzae) and 7F3 (which recognized the P6 protein of NT H. influenzae but not that of H. haemolyticus) (19) has some merit. Alternatively, a multiplex PCR based on H. haemolyticus sodC and a gene unique to NT H. influenzae might be developed.…”

Section: Infection With Nontypeable (Nt)mentioning

confidence: 99%

See 1 more Smart Citation

Presence of Copper- and Zinc-Containing Superoxide Dismutase in Commensal Haemophilus haemolyticus Isolates Can Be Used as a Marker To Discriminate Them from Nontypeable H. influenzae Isolates

Fung¹,

O'Dwyer²,

Sinha³

et al. 2006

J Clin Microbiol

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Haemophilus haemolyticus:A Human Respiratory Tract Commensal to Be Distinguished fromHaemophilus influenzae

Cited by 203 publications

References 46 publications

Phylogenetic relatedness and diversity of non-typable Haemophilus influenzae in the nasopharynx and middle ear fluid of children with acute otitis media

Phylogenetic relatedness and diversity of non-typable Haemophilus influenzae in the nasopharynx and middle ear fluid of children with acute otitis media

Infection as a comorbidity of COPD

Presence of Copper- and Zinc-Containing Superoxide Dismutase in Commensal Haemophilus haemolyticus Isolates Can Be Used as a Marker To Discriminate Them from Nontypeable H. influenzae Isolates

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