Rapid Identification and Subtyping of Helicobacter cinaedi Strains by Intact-Cell Mass Spectrometry Profiling with the Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

Taniguchi, Takako; Sekiya, Ayumi; Higa, Mariko; Saeki, Yûji; Umeki, Kazumi; Okayama, Akira; Hayashi, Tetsuya; Misawa, Naoaki

doi:10.1128/jcm.01798-13

Cited by 30 publications

(24 citation statements)

References 41 publications

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“…H. cinaedi is not included in the FDA-cleared Bruker Biotyper or Vitek MS (bioMérieux) databases as of the time of writing this article, although we identified the isolate to the species level (score of Ͼ2.0) with the Bruker Biotyper RUO database. In addition, Taniguchi et al showed that it is possible to use individual MALDI-TOF profiles to both identify and subtype H. cinaedi (5).…”

Section: Discussionmentioning

confidence: 99%

The Brief Case: Bacteremia Caused by Helicobacter cinaedi

Bateman

Butler-Wu

2017

J Clin Microbiol

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A 61-year-old male with relapsed multiple myeloma presented to clinic with fatigue and chills. The patient had undergone two rounds of autologous stem cell transplantation in 2012 and was undergoing chemotherapy with pomalidomide, cyclophosphamide, and dexamethasone. He was admitted for neutropenic fever (absolute neutrophil count of 1.4 ϫ 10 9 /liter, temperature of 38.4°C). His physical exam was normal, and he denied any other symptoms. Two sets of blood cultures were obtained (VersaTREK Redox; Trek Diagnostic Systems), and the patient was started on levofloxacin, vancomycin, and cefepime. His fever subsided after 24 h, and he was discharged home to complete a 30-day course of oral levofloxacin. After 2.5 days of incubation, aerobic bottles from both blood culture sets were positive for growth of a curved Gram-negative bacillus with a morphology resembling "gull wings" (Fig. 1). Subculture to Trypticase soy agar with 5% sheep blood (TSA-B) and chocolate agar was performed, and media were incubated at 35°C with 5% CO 2. Subculture to brucella agar (with blood, hemin, and vitamin K) was also performed, and the culture was incubated anaerobically (all media from Remel). Because of the Gram stain morphology, subculture to Campylobacter CVA blood agar (Hardy Diagnostics) was performed, and the culture was incubated at 42°C under microaerobic conditions (6% O 2 , 7.2% CO 2 , 7.2% H 2 , and 79.7% N 2 in an Anoxomat jar). All four media were negative for growth after 7 days of incubation. To establish the etiology of infection, broad-range 16S rRNA gene PCR and sequencing were performed directly on the positive blood culture broth (1). The bacterium was identified as Helicobacter cinaedi with 100% identity to multiple H. cinaedi sequences, including the type strain (ATCC strain BAA-847), by a standard nucleotide BLAST search (NCBI). Once the identification was established, subculture was repeated using buffered charcoal yeast extract (BCYE), brain heart infusion with sheep blood (BHI-B), and brucella agars incubated under microaerobic conditions at 35°C. Pinpoint growth was observed on all three types of media after 48 h of incubation. There are no interpretive criteria for antimicrobial susceptibility testing of Helicobacter cinaedi. However, MICs were determined by gradient diffusion on BHI-B agar using Etests (bioMérieux) incubated under microaerobic conditions for 48 h. The observed MICs were 16 g/ml for levofloxacin, 2 g/ml for clarithromycin, and 0.25 g/ml for tetracycline, with testing for these specific antimicrobials performed at the request of the treating physician. The patient returned to the same clinic 8 days after discharge, reporting fatigue and dizziness. He was afebrile (36.8°C) but neutropenic and was given intravenous hydration. Two sets of blood cultures were obtained. Levofloxacin was discontinued, and both ceftriaxone and doxycycline were initiated at this time. Importantly, identification of the patient's blood culture isolate by 16S rRNA gene sequencing had been reported 1 day prior to the pati...

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Section: Discussionmentioning

confidence: 99%

The Brief Case: Bacteremia Caused by Helicobacter cinaedi

Bateman

Butler-Wu

2017

J Clin Microbiol

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“…Thus, a human clinical strain, H. cinaedi N73 strain, that forms single colonies on agar plates was used in this study. The N73 strain had been isolated from human blood cultures during routine diagnosis of bacteremia in a patient admitted to the University of Miyazaki Hospital . It was grown on Brucella agar (Becton Dickinson, BD Biosciences, Tokyo, Japan) containing 5% defibrinated horse blood (Nippon Biotest Laboratories, Tokyo, Japan) at 37°C for 2–3 days under microaerobic conditions (75% N 2 , 10% CO 2 , 5% H 2 and 10% O 2 ).…”

Section: Methodsmentioning

confidence: 99%

Extraintestinal infection of Helicobacter cinaedi induced by oral administration to Balb/c mice

Taniguchi

Saeki

Okayama

et al. 2017

Microbiology and Immunology

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Although Helicobacter cinaedi was initially considered an opportunistic pathogen in immunocompromised patients, it was later shown to also infect immunocompetent and healthy individuals. Sporadic bacteremia due to H. cinaedi has frequently been reported; however, whether the bacterium can be translocated after passage through the intestinal mucosa remains unclear. In the present study, a preclinical small animal model that faithfully reproduces H. cinaedi infection in humans was developed. Balb/c male mice were orally inoculated with a single dose of 6.8 × 10 CFU of a human clinical H. cinaedi strain. The organism persistently colonized the intestinal tract of the mice, particularly the cecum and colon, for at least 56 days, and the bacteria were excreted in the feces. Although inoculated bacteria were recovered from the spleen, liver, kidney, lung, bladder and mesenteric lymph nodes during the first 2 weeks of bacteremia, the organism was not isolated from these organs after 4 weeks, suggesting that complement- and antibody-mediated serum sensitivity account for the relatively low frequency of systemic infection. However, H. cinaedi was isolated from the biceps femoris, triceps branchii, latissimus dorsi, and trapezius muscles beyond 2 weeks after infection and after production of specific anti-H. cinaedi IgM and IgG antibodies. The present findings suggest that experimental infection of Balb/c mice with H. cinaedi may be a useful model for further studies of H. cinaedi pathogenesis, prophylaxis or therapeutic interventions in vivo.

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“…Vandamme et al also described one isolate from dog faeces (LMG 16312) that was not confidently identified as H. cinaedi by its phenotype [40]. A similar discrepancy between human and animal isolates has been recently recognized using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system [36].…”

Section: Introductionmentioning

confidence: 96%