Haemophilus segnis: a rare cause of endocarditis

Somers, C.; Millar, B. Cherie; Xu, Jianguo; Moore, David; Moran, Angelica; Maloney, Christopher G.; Keogh, Brian; Murphy, Philip G.; Moore, John E.

doi:10.1046/j.1469-0691.2003.00703.x

Cited by 17 publications

(8 citation statements)

References 14 publications

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“…It has been reported by our group and others that the nomenclature may differ based on the technology used (30). The fact that the species identified in our study, including Leptotrichia goodfellowii, N. flavescens, N. subflava, A. segnis, Campylobacter showae, and Capnocytophaga granulosa, have been associated with extraoral infections involving hematogenous transmission, such as endocarditis, meningitidis, and extraoral abscesses (2,16,19,36,50,53), indicates their ability to translocate to different body parts and their virulence potential.…”

Section: Discussionmentioning

confidence: 62%

Transmission of Diverse Oral Bacteria to Murine Placenta: Evidence for the Oral Microbiome as a Potential Source of Intrauterine Infection

et al. 2010

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Microbial infection of the intrauterine environment is a major cause of preterm birth. The current paradigm indicates that intrauterine infections predominantly originate from the vaginal tract, with the organisms ascending into the sterile uterus. With the improvements in technology, an increasing number of bacterial species have been identified in intrauterine infections that do not belong to the vaginal microflora. We have demonstrated previously that intrauterine infections can originate from the oral cavity following hematogenous transmission. In this study, we begin to systemically examine what proportion of the oral microbiome can translocate to the placenta. Pooled saliva and pooled subgingival plaque samples were injected into pregnant mice through tail veins to mimic bacteremia, which occurs frequently during periodontal infections. The microbial species colonizing the murine placenta were detected using 16S rRNA gene-based PCR and clone analysis. A diverse group of bacterial species were identified, many of which have been associated with adverse pregnancy outcomes in humans although their sources of infection were not determined. Interestingly, the majority of these species were oral commensal organisms. This may be due to a dose effect but may also indicate a unique role of commensal species in intrauterine infection. In addition, a number of species were selectively "enriched" during the translocation, with a higher prevalence in the placenta than in the pooled saliva or subgingival plaque samples. These observations indicate that the placental translocation was species specific. This study provides the first insight into the diversity of oral bacteria associated with intrauterine infection.Preterm birth (PTB) is a significant public health concern, affecting 12.7% of births in the United States. This rate reflects a 36% increase in the past 25 years. Among these, the very preterm births, i.e., those occurring before 32 weeks of gestation, are the most costly and medically relevant group, accounting for approximately 2% of all deliveries. Intrauterine infection has been recognized as a major cause of PTB. The infection rate is inversely related to the gestational age and is highly prevalent among the very preterm deliveries (24). Intrauterine infection has also been implicated in other adverse pregnancy outcomes, such as late miscarriage and stillbirth (25). A wide variety of bacterial species have been identified in the infections, with Ureaplasma urealyticum, Mycoplasma hominis, Bacteroides spp., Gardnerella vaginalis, and Fusobacterium nucleatum (24, 31) as the most prevalent. It has been suggested that the majority of these bacterial species are of relatively low virulence. However, once inside the uterus, they stimulate the synthesis and release of proinflammatory cytokines, neutrophil infiltration and activation, and prostaglandin and metalloprotease synthesis and release, leading to cervical ripening, membrane weakening and rupture, uterine contractions, and PTB (24).The current paradigm ind...

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Section: Discussionmentioning

confidence: 62%

Transmission of Diverse Oral Bacteria to Murine Placenta: Evidence for the Oral Microbiome as a Potential Source of Intrauterine Infection

et al. 2010

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“…H. influenzae is a more common etiology of adult bacteremia than other Haemophilus and Aggregatibacter spp. combined (213); consequently, the isolation of H. influenzae from blood is rarely a sign of infective endocarditis, and the species is sometimes omitted from the HACEK group (126,214 (210,215,216).…”

Section: Infectious Endocarditis and The Hacek Groupmentioning

confidence: 99%

Classification, Identification, and Clinical Significance of Haemophilus and Aggregatibacter Species with Host Specificity for Humans

2014

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SUMMARY The aim of this review is to provide a comprehensive update on the current classification and identification of Haemophilus and Aggregatibacter species with exclusive or predominant host specificity for humans. Haemophilus influenzae and some of the other Haemophilus species are commonly encountered in the clinical microbiology laboratory and demonstrate a wide range of pathogenicity, from life-threatening invasive disease to respiratory infections to a nonpathogenic, commensal lifestyle. New species of Haemophilus have been described ( Haemophilus pittmaniae and Haemophilus sputorum ), and the new genus Aggregatibacter was created to accommodate some former Haemophilus and Actinobacillus species ( Aggregatibacter aphrophilus , Aggregatibacter segnis , and Aggregatibacter actinomycetemcomitans ). Aggregatibacter species are now a dominant etiology of infective endocarditis caused by fastidious organisms (HACEK endocarditis), and A. aphrophilus has emerged as an important cause of brain abscesses. Correct identification of Haemophilus and Aggregatibacter species based on phenotypic characterization can be challenging. It has become clear that 15 to 20% of presumptive H. influenzae isolates from the respiratory tracts of healthy individuals do not belong to this species but represent nonhemolytic variants of Haemophilus haemolyticus . Due to the limited pathogenicity of H. haemolyticus , the proportion of misidentified strains may be lower in clinical samples, but even among invasive strains, a misidentification rate of 0.5 to 2% can be found. Several methods have been investigated for differentiation of H. influenzae from its less pathogenic relatives, but a simple method for reliable discrimination is not available. With the implementation of identification by matrix-assisted laser desorption ionization–time of flight mass spectrometry, the more rarely encountered species of Haemophilus and Aggregatibacter will increasingly be identified in clinical microbiology practice. However, identification of some strains will still be problematic, necessitating DNA sequencing of multiple housekeeping gene fragments or full-length 16S rRNA genes.

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“…In many situations, 16S rDNA sequencing is the ultimate solution to identification of aetiological agents of infectious diseases caused by rarely encountered bacteria [11][12][13][14][15][16][17][18][19][20][21][22]. This not only allows correct identification and selection of appropriate treatment, but also contributes to a better understanding of the epidemiology and pathogenic role of these bacteria, which has not been possible in the past.…”

Section: E T H O D Smentioning

confidence: 99%

“…In another study, six cases of ‘ S. milleri ’ endocarditis were attributed to S. anginosus , suggesting that S. anginosus had the highest propensity to cause infective endocarditis among the three species of the ‘ S. milleri group’ [62]. Using this ‘state‐of‐the‐art’ technique, it was also found that Haemophilus segnus is an important cause of non‐ H. influenzae bacteraemia [19,63,64]. In addition, the use of 16S rDNA sequencing for clinically ‘unidentifiable’ bacteria could have clinical significance regarding the choice of antibiotic regimen as well as the duration of treatment.…”

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confidence: 99%

Then and now: use of 16S rDNA gene sequencing for bacterial identification and discovery of novel bacteria in clinical microbiology laboratories

Woo

Lau

Teng

et al. 2008

Clinical Microbiology and Infection

694

424

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In the last decade, as a result of the widespread use of PCR and DNA sequencing, 16S rDNA sequencing has played a pivotal role in the accurate identification of bacterial isolates and the discovery of novel bacteria in clinical microbiology laboratories. For bacterial identification, 16S rDNA sequencing is particularly important in the case of bacteria with unusual phenotypic profiles, rare bacteria, slow-growing bacteria, uncultivable bacteria and culture-negative infections. Not only has it provided insights into aetiologies of infectious disease, but it also helps clinicians in choosing antibiotics and in determining the duration of treatment and infection control procedures. With the use of 16S rDNA sequencing, 215 novel bacterial species, 29 of which belong to novel genera, have been discovered from human specimens in the past 7 years of the 21st century (2001-2007). One hundred of the 215 novel species, 15 belonging to novel genera, have been found in four or more subjects. The largest number of novel species discovered were of the genera Mycobacterium (n = 12) and Nocardia (n = 6). The oral cavity/dental-related specimens (n = 19) and the gastrointestinal tract (n = 26) were the most important sites for discovery and/or reservoirs of novel species. Among the 100 novel species, Streptococcus sinensis, Laribacter hongkongensis, Clostridium hathewayi and Borrelia spielmanii have been most thoroughly characterized, with the reservoirs and routes of transmission documented, and S. sinensis, L. hongkongensis and C. hathewayi have been found globally. One of the greatest hurdles in putting 16S rDNA sequencing into routine use in clinical microbiology laboratories is automation of the technology. The only step that can be automated at the moment is input of the 16S rDNA sequence of the bacterial isolate for identification into one of the software packages that will generate the result of the identity of the isolate on the basis of its sequence database. However, studies on the accuracy of the software packages have given highly varied results, and interpretation of results remains difficult for most technicians, and even for clinical microbiologists. To fully utilize 16S rDNA sequencing in clinical microbiology, better guidelines are needed for interpretation of the identification results, and additional/supplementary methods are necessary for bacterial species that cannot be identified confidently by 16S rDNA sequencing alone.

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Haemophilus segnis: a rare cause of endocarditis

Cited by 17 publications

References 14 publications

Transmission of Diverse Oral Bacteria to Murine Placenta: Evidence for the Oral Microbiome as a Potential Source of Intrauterine Infection

Transmission of Diverse Oral Bacteria to Murine Placenta: Evidence for the Oral Microbiome as a Potential Source of Intrauterine Infection

Classification, Identification, and Clinical Significance of Haemophilus and Aggregatibacter Species with Host Specificity for Humans

Then and now: use of 16S rDNA gene sequencing for bacterial identification and discovery of novel bacteria in clinical microbiology laboratories

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