Coryneform bacteria isolated from middle ear fluid

Reviewing the Pathogenic Potential of the Otitis-Associated Bacteria Alloiococcus otitidis and Turicella otitidis

Alloiococcus otitidis and Turicella otitidis are common bacteria of the human ear. They have frequently been isolated from the middle ear of children with otitis media (OM), though their potential role in this disease remains unclear and confounded due to their presence as commensal inhabitants of the external auditory canal. In this review, we summarize the current literature on these organisms with an emphasis on their role in OM. Much of the literature focuses on the presence and abundance of these organisms, and little work has been done to explore their activity in the middle ear. We find there is currently insufficient evidence available to determine whether these organisms are pathogens, commensals or contribute indirectly to the pathogenesis of OM. However, building on the knowledge currently available, we suggest future approaches aimed at providing stronger evidence to determine whether A. otitidis and T. otitidis are involved in the pathogenesis of OM. Such evidence will increase our understanding of the microbial risk factors contributing to OM and may lead to novel treatment approaches for severe and recurrent disease.

Review of otorrhea microbiology: is there a pathogenic role of corynebacter?

OBJECTIVE

Identification of a causative pathogen in otologic infections assists in maximizing therapy efficacy particularly in refractory and chronic cases. Current standards for treatment of otologic infections focus on targeted species (spp.) that are assumed to be the most common pathogens. Corynebacterium spp. may play a pathogenic role but are not routinely speciated or included in antibiotic susceptibility analysis. Our objective is to investigate the prevalence and pathogenicity of nondiphtheroid Corynebacterium spp. in commonly encountered purulent and mucopurulent otologic infections.

STUDY DESIGN

Retrospective case review.

SETTING

Academic tertiary referral center.

PATIENTS

Review of 140 microbiology cultures from adults and children presenting with purulent and mucopurulent otologic infections from 2010 to 2012.

INTERVENTION(S)

Clinical history, demographics, and microbiology cultures with speciation and antibiotic susceptibility analyses.

MAIN OUTCOME MEASURE(S)

Microbiologic speciation and census, species association with clinical characteristics, antibiotic susceptibility to oral and systemic agents, therapy frequency and agent selection.

RESULTS

Corynebacterium spp. was the second most common bacteria isolated from patients with clinically significant otologic infections. Corynebacterium spp. were found in 24 (33.3%) unique patients with otologic infections and were the only pathogen isolated in six (8.33%) patients. Corynebacterium-positive infections were significantly associated with the use of hearing aids, a diagnosis of chronic granular myringitis, and less otalgia. Corynebacterium isolates were highly resistant to first-line fluoroquinolone therapy. The majority of patients with Corynebacterium-positive infections harbored at least one resistant strain, and patients with strains resistant to first-line topical therapy had a nonsignificant trend to an alteration in antibiotic therapy after antibiotic susceptibility data became available.

CONCLUSION

Corynebacterium spp. may be underestimated in their potential to cause clinically significant otologic infections. Our results indicate a potential need for expanding surveillance for Corynebacterium spp.

Turicella otitidis and Corynebacterium auris: 20 years on

Turicella otitidis and Corynebacterium auris, described as new species 20 years ago, have been isolated mainly from the external ear canal and middle ear fluid. While their taxonomic position has been clearly established, their diagnosis in the routine laboratory is difficult. The question of their pathogenic potential in otitis is still open but might be elucidated better if corynebacteria are speciated more often.

Antibiotic resistance and otomycosis in the draining ear: culture results by diagnosis

OBJECTIVE

The objective of the study was to better define changes in the bacteriology of suppurative otitis in recent years and the role of cultures in the management of these patients.

STUDY DESIGN

A retrospective review was performed.

METHODS

Outpatient records from 170 patients collected over 3 years with information regarding the bacteria cultured, antibiotic resistance, and clinical diagnosis were analyzed.

RESULTS

A large variety of organisms were seen, with Staphylococcus aureus, Corynebacterium sp, and Pseudomonas aeruginosa being the most common. Forty percent of cultures showed bacteria with moderate antibiotic resistance, whereas 5% were sensitive to only intravenous antibiotics. Resistant bacteria were found in all diagnosis categories and were significantly higher in cases of chronic mastoiditis. The rate of methicillin-resistant S aureus infections was 7.8% and was significantly higher in cases of chronic myringitis. Fungus was often cultured in patients without clinical signs of otomycosis.

CONCLUSIONS

Community-acquired ear infections may be caused by antibiotic-resistant bacteria in a substantial number of patients. In our opinion, outpatient cultures play an important role in the management of suppurative otitis.

[Turicella otitidis infection: otitis media complicated by mastoiditis]

Turicella otitidis is a nonfermentative, Gram-positive bacillus, which is almost exclusively isolated from the ear. Few cases of infection caused by T. otitidis have been reported in the literature, but the pathogenic potential of this little-known bacterium remains controversial, particularly in acute and chronic otitis media.

CLINICAL OBSERVATIONS

A retrospective study of T. otitidis isolated in the University Hospital of Montpellier in 2004 found T. otitidis in 13 patients. Among them, a 3-year-old girl had presented with acute and perforated otitis media and mastoiditis caused by T. otitidis, thereby confirming the pathogenic effect of this bacterium.

CONCLUSION

T. otitidis is relatively frequently isolated from middle ear samples in healthy patients. However, T. otitidis has been implicated in serious cases of infection and should be considered an opportunistic pathogen. Its clinical significance can be difficult to establish and each case should be carefully interpreted. From a bacteriological point of view, T. otitidis should be precisely identified to obtain more information regarding its role in clinical pathology.

[Microbiological diagnosis of upper respiratory tract infections]

Upper respiratory tract (URT) infections are common and account for more medical visits than any other type of infectious disease. Diagnostic procedures for the following syndromes are included in this report: Streptococcal and nonstreptococcal pharyngitis, laryngeal syndromes, otitis, sinusitis, and others caused by unusual and/or uncommon bacteria or fungi, including Lemierre's disease, Vincent's angina, pharyngeal and peritonsillar abscesses, diphtheria, candidiasis, and zygomycoses. Detailed information is provided on specimen collection and processing, selection of laboratory tests, interpretation of findings, reporting results, additional procedures for uncommon infections, and the use of new techniques. All the information included in this article is contained in the Standard Operating Procedures for Clinical Microbiology (http://www.seimc.org/protocolos/microbiologia/).

Characterization of a truncated lipoarabinomannan from the Actinomycete Turicella otitidis

Lipoarabinomannan (LAM) lipoglycans have been characterized from a range of mycolic acid-containing actinomycetes and from the amycolate actinomycete Amycolatopsis sulphurea. To further understand the structural diversity of this family, we have characterized the lipoglycan of the otic commensal Turicella otitidis. T. otitidis LAM (TotLAM) has been determined to consist of a mannosyl phosphatidylinositol anchor unit carrying an (alpha 1-->6)-linked mannan core and substituted with terminal-arabinosyl branches. Thus, TotLAM has a novel truncated LAM structure. Using the human monocytic THP-1 cell line, it was found that TotLAM exhibited only minimal ability to induce tumor necrosis factor alpha. These findings contribute further to our understanding of actinomycete LAM diversity and allow further speculation as to the correlation between LAM structure and the immunomodulatory activities of these lipoglycans.

Acute and chronic otitis media and Turicella otitidis: a controversial association

Turicella otitidis is a non-fermenting Gram-positive bacillus isolated almost exclusively from ear exudates. Its significance in acute or chronic otitis media is controversial. Over a 12-month period, T. otitidis was isolated from nine ear exudates from seven patients. Most of these were cases of spontaneous drainage following recurrence of otitis media after antimicrobial therapy that was ineffective against T. otitidis. The MICs of penicillin, levofloxacin, linezolid and vancomycin were very low for all the isolates studied, but most isolates displayed high resistance to macrolides and lincosamides.

Culture-independent molecular analysis of microbial constituents of the healthy human outer ear

Molecular-phylogenetic sequence analyses have provided a new perspective on microbial communities by allowing the detection and identification of constituent microorganisms in the absence of cultivation. In this study we used broad-specificity amplification of ribosomal DNA (rDNA) genes to survey organisms present in the human outer ear canal. Samples were obtained from 24 individuals, including members of three extended families, in order to survey the resident microbiota and to examine microbial population structures in individuals related by familial or household associations. To examine the stability of the microbial populations, one individual was sampled four times and another twice over a 14-month period. We found that a distinct set of microbial types was present in the majority of the subjects sampled. The two most prevalent rDNA sequence types that were identified in multiple individuals corresponded closely to those of Alloiococcus otitis and Corynebacterium otitidis, commonly thought to be associated exclusively with infections of the middle ear. Our results suggest, therefore, that the outer ear canal may serve as a reservoir for normally commensal microbes that can contribute to pathogenesis upon introduction into the middle ear. Alternatively, culture analyses of diseases of the middle ear may have been confounded by these contaminating commensal organisms.

Turicella otitidis and Corynebacterium auris do not cause otitis media with effusion in children

BACKGROUND

The recently described coryneform bacteria and were first detected in the middle ear of patients with acute otitis media and chronic otitis media. Whether these bacteria play an essential role in the pathogenesis of otitis media with effusion (OME) is unclear.

METHODS

In a prospective study 60 children with OME and 205 controls were evaluated to determine the incidence of and. Swabs from the external auditory canal (EAC) and the middle ear effusion (MEE) of OME children undergoing tympanotomy, ventilation tube insertion or both were cultured. Swabs from the EAC from healthy children served as controls.

RESULTS

In control children was found in EAC swabs from 23 of 205 (11.2%) and in 32 of 205 (15.6%). was isolated from 14 of 60 (23.3%) OME patients from the EAC only and in 6 of 60 (10.0%) OME patients from both EAC and MEE. was isolated in 2 of 60 (3.3%) from the EAC only and in 1 of 60 (1.7%) from both EAC and MEE. In no patient did or grow exclusively from MEE.

CONCLUSION

and may be part of the normal bacterial flora of the EAC in some children. Neither organism seems to cause OME in children.

Turicella otitidis mastoiditis in a healthy child

Turicella otitidis, a coryneform bacterium, has been associated with acute otitis media. A 5-year-old girl developed acute mastoiditis. Turicella was isolated from the right and left middle ear fluid.

Isolation of a Kawasaki disease-associated bacterial sequence from peripheral blood leukocytes

BACKGROUND

The clinical and epidemiologic features of Kawasaki disease (KD) suggest an infectious etiology, but the agent(s) remains unknown. We aimed to isolate the causative bacterial gene from peripheral blood leukocytes of patients with acute KD.

METHODS

Nested polymerase chain reaction (PCR) assay was used to amplify the bacterial 16S ribosomal RNA gene (rDNA). The amplified DNA were cloned into a plasmid vector and sequenced. Phylogenetic analysis was performed with clustal W program and the neighbour-joining method.

RESULTS

First, the PCR reagents were examined by the PCR assay using conservative primers and we found more than 10 16S rDNA sequences contaminating the reagents. We then examined five KD patients using the PCR assay, excluding the contaminated sequences, and obtained five 16S rDNA sequences as possible KD-associated sequences. The primers specific to each 16S rDNA sequence were synthesized and used for specific PCR assays. Only the PCR assay specific to the 16S rDNA sequence termed 16S71-33 did not show any false positives with the control DNA from non-KD patients. The 16S71-33 sequence was positive in three of 20 patients with acute KD before gamma-globulin therapy, but it became negative after therapy. The phylogenetic analysis showed a new species of the genus Corynebacterium as the origin of the 16S71-33 sequence.

CONCLUSIONS

These data show that an infectious KD agent is traced in peripheral leukocytes and that a new Corynebacterium species may be responsible for KD in some cases. The true frequency and the role of the new Corynebacterium in KD would be clarified by measuring specific antibodies to it.

Clinical microbiology of coryneform bacteria

Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed.

Genetic identification of members of the genus Corynebacterium at genus and species levels with 16S rDNA-targeted probes

16S rRNA gene-targeted probes were designed for the identification of corynebacteria at the genus and species levels. The genus-specific probe hybridized all clinically important members of the genus Corynebacterium and could distinguish them from other coryneform bacteria and phylogenetically related high G+C% gram-positive bacteria, including Actinomyces, Rhodococcus, Gordona, Nocardia, Streptomyces, Brevibacterium and Mycobacterium. The species-specific probes for C. jeikeium and C. diphtheriae could differentiated these two species from other members of this genus. The probes were used to select corynebacteria among gram-positive clinical isolates which had been tentatively identified as corynebacteria by biochemical tests. We screened 59 strains with the genus-specific probe; 51 strains hybridized to the genus-specific probe, 8 did not. Of the 51 strains that hybridized to the genus-specific probe, 1 hybridized to the C. diphtheriae species probe and 13 hybridized to the C. jeikeium species probe. The 8 strains that did not hybridize to the genus probe were further characterized by analyzing cell wall diaminopimelic acid and partial 16S rRNA sequencing. The results indicated that these strains were distributed in the genera Arthrobacter and Brevibacterium.

Identification of Turicella otitidis isolated from a patient with otorrhea associated with surgery: differentiation from Corynebacterium afermentans and Corynebacterium auris

Turicella otitidis is a newly described coryneform bacterium isolated from middle ear fluids. We report here on the diagnosis of a strain isolated from otorrhea. The API Coryne system (bioMérieux, Marcy I'Etoile, France) used alone failed to differentiate T. otitidis, Corynebacterium afermentans, and Corynebacterium auris (ANF group). Biochemical tests such as DNase, enzymatic reactions (API ZYM; bioMérieux), and carbon substrate assimilation tests (Biotype 100; bioMérieux) allow presumptive identification. However, only chemotaxonomy and molecular biology can achieve unequivocal differentiation among these three species.

Human infections caused by Brevibacterium casei, formerly CDC groups B-1 and B-3

Forty-one clinical strains of CDC coryneform groups B-1 and B-3 were compared biochemically, by analysis of cell wall sugars, amino acids, and cellular fatty acids, and by DNA relatedness to the type strains of Brevibacterium casei, Brevibacterium epidermidis, and Brevibacterium linens. Twenty-two strains were shown to be B. casei, while five other strains formed a phenotypically inseparable genomospecies in the same genus. The remaining isolates were genetically heterogeneous, and most are probably members of the genus Brevibacterium. They were not further identified, but they were biochemically distinguishable from B. casei. Eleven of the clinical strains of B. casei were isolated from blood, and two each were isolated from cerebrospinal fluid and from pleural fluid. At least five isolates were from multiple blood or cerebrospinal fluid cultures. To our knowledge, these strains are the first described clinical isolates identified as B. casei, which was previously considered to be a nonpathogenic species.