First adult case of Helicobacter cinaedi meningitis

Helicobacter cinaedi Infections in Emergency Departments: A Descriptive Study

AIM

Helicobacter cinaedi, a Gram-negative spiral bacterium, is a rare cause of bacteremia in humans. Unfortunately, little is known about H. cinaedi infections in emergency departments (EDs). We aimed to describe the clinical features of H. cinaedi infections in the ED.

METHODS

We conducted a descriptive study at the ED of Kobe City General Hospital (KCGH) in Japan between November 2011 and December 2020. We included all ED patients with H. cinaedi infections. We retrospectively obtained the patient data from electronic medical records and described the patient characteristics, clinical course, and management of H. cinaedi infections.

RESULTS

A total of 22 patients in the ED were diagnosed with H. cinaedi infections, and all of them were detected through blood cultures. The chief complaints were vague: fever (18/22, 81.8%), chills (10/22, 45.5%), and localized pain or tenderness (8/22, 36.4%). Patients with complicated cases were also reported in the ED; three patients had vertebral osteomyelitis, two had infected aortic aneurysms, and another two had infected cysts (renal cyst and pancreatic cyst with concomitant empyema). Tetracycline (minocycline) was primarily prescribed and administered intravenously in five of 15 (33.3%) and orally in nine of 20 (45.0%) patients. Only one (4.5%) patient required surgical interventions. None of the patients died in the hospital.

CONCLUSIONS

We reported the clinical features of H. cinaedi infections in the ED. Although some patients developed complicated infections, the prognosis was not poor under appropriate treatment, and most of them were successfully treated with antibiotics, primarily tetracycline.

Enterohepatic Helicobacter species - clinical importance, host range, and zoonotic potential

The genus Helicobacter defined just over 30 years ago, is a highly diverse and fast-growing group of bacteria that are able to persistently colonize a wide range of animals. The members of this genus are subdivided into two groups with different ecological niches, associated pathologies, and phylogenetic relationships: the gastric Helicobacter (GH) and the enterohepatic Helicobacter (EHH) species. Although GH have been mostly studied, EHH species have become increasingly important as emerging human pathogens and potential zoonotic agents in the last years. This group of bacteria has been associated with the development of several diseases in humans from acute pathologies like gastroenteritis to chronic pathologies that include inflammatory bowel disease, and liver and gallbladder diseases. However, their reservoirs, as well as their routes of transmission, have not been well established yet. Therefore, this review summarizes the current knowledge of taxonomy, epidemiology, and clinical role of the EHH group.

Helicobacter cinaedi-infected chronic subdural hematoma mimicking an expanding hematoma: A case report

Background:

We present the rare case of a spontaneous intracranial subdural empyema caused by Helicobacter cinaedi in a preexisting chronic subdural hematoma (CSDH).

Case Description:

A 72-year-old man with a history of the right CSDH that remained radiologically unchanged for the past 2 years with conservative management was transferred to our hospital because of fever and convulsive seizure. Systemic sources of infection were not identified. Fever and extremely high levels of serum C-reactive protein (CRP) spontaneously improved without antibacterial therapy. One month after the fever disappeared, brain computed tomography (CT) showed an increase in CSDH size. Mildly elevated CRP levels persisted without fever. Interval changes in shape on CT and hyperintense signals on diffusion-weighted magnetic resonance imaging (DWI) within the CSDH were observed with no neurological deficits. Five months later, the patient underwent craniotomy for a progressively enlarged CSDH. An infected organized hematoma was found, and copious pus was evacuated. Subsequently, an infected subdural hematoma (ISH) was diagnosed. Although bacterial cultures of the purulent specimen were negative, H. cinaedi was identified by gene sequencing analysis. Six months post antibiotic therapy, the ISH was under control, and abnormal DWI signals disappeared.

Conclusion:

To the best of our knowledge, this is the first report of ISH caused by H. cinaedi. This case suggests that ISH can follow a chronic course, mimicking the progressive expansion of subdural hematoma, and that H. cinaedi should be considered as a causative organism of ISH especially when conventional cultures are negative.

First case report of thyroid abscess caused by Helicobacter cinaedi presenting with thyroid storm

Background

Helicobacter cinaedi is a microaerobic Gram-negative spiral-shaped bacterium that causes enteritis, cellulitis, and bacteremia in both immunocompromised and immunocompetent patients. While there have been increasing numbers of reported H. cinaedi infections recently, there has been no thyroid abscess case caused by H. cinaedi presenting with thyroid storm.

Case presentation

A 50-year-old Japanese man presented with a 9-day history of high fever associated with palpitations, dry cough, and chronic diarrhea. The patient had a history of Basedow’s disease that had been treated with thiamazole in the past. During the current episode, the patient was diagnosed with thyroid storm and treated accordingly. The blood culture taken on admission was positive for H. cinaedi. This finding was confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOFMS). A systemic computed tomography (CT) scan revealed a thyroid abscess as the site of infection and cause of the bacteremia. The 16S rRNA gene sequencing identified the pathogen of thyroid abscess as H. cinaedi. Clinical symptoms and laboratory data normalized on admission day 7 after treatment with both effective antibiotics and antithyroid drugs.

Conclusions

The case study described a patient with a history of Basedow’s disease that presented with a thyroid abscess caused by H. cinaedi with symptoms similar to those of thyroid storm. While this bacterium has been implicated in other infections, we believe this is the first time the bacteria has been documented to have caused a thyroid abscess.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3808-7) contains supplementary material, which is available to authorized users.

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

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 × 10⁷ 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.

Unusual manifestation of Helicobacter cinaedi infection: a case report of intracranial subdural empyema and bacteremia

Background

There have been various reports concerning Helicobacter cinaedi infections. However, few reports have examined central nervous system infections.

Case presentation

A 52-year-old man was transferred from the local hospital because of a persistent headache and suspected intracranial subdural empyema. Neurosurgical drainage was performed via burr holes. Gram staining and results from abscess cultures were negative. The blood culture yielded H. cinaedi. He was given an antibiotic regimen consisting of 2 g of ceftriaxone twice a day, but the size of the abscess was not reduced in size at all after 3 weeks of treatment. Neurosurgical drainage was performed again, and the antimicrobial regimen was switched to 2 g of meropenem 3 times a day. The size of the abscess was reduced after 2 weeks of the second drainage and antimicrobial drug change to meropenem. After 4 weeks treatment with meropenem, the patient was discharged, and his symptoms had completely resolved.

Conclusions

H. cinaedi infection should be considered in the differential diagnosis of subdural empyema cases for which Gram staining and abscess culture results are negative. Meropenem can be a first-line drug of choice or an effective alternative treatment for H. cinaedi central nervous system infections.

The First Case Report of Cerebral Cyst Infection Due to Helicobacter cinaedi

We report the first case of cerebral cyst infection by Helicobacter cinaedi, a fastidious spiral-shaped gram-negative rod bacterium. A 70-year-old man visited Tokyo Medical University Hospital with persisting fever since 2 weeks. He underwent surgery and radiotherapy for parapharyngeal space squamous cell carcinoma 10 years ago. The radiotherapy resulted in a cerebral cyst as a side effect, and an Ommaya reservoir was inserted into the cyst. Blood culture and analysis of the brain cyst fluid revealed the presence of spiral-shaped gram-negative rod bacteria, which were identified as H. cinaedi by polymerase chain reaction. Initially, we administered clarithromycin (400 mg per day). After H. cinaedi infection was confirmed, the treatment was changed to meropenem (MEPM 6 g per day). The patient was treated for 43 days in the hospital with intravenous meropenem, and his clinical course was satisfactory. On the 44th day, he was discharged and prescribed oral minocycline (MINO 200 mg per day). After discharge, the patient's H. cinaedi infection did not recur. Our case illustrated the wide clinical spectrum of H. cinaedi as well as the effectiveness of antibiotic therapy comprising MERM and MINO for treating central nervous system infection by this organism.

Clinical Features of Community-Acquired Helicobacter cinaedi Bacteremia

BACKGROUND

There are growing numbers of reports concerning the clinical and pathological features of Helicobacter cinaedi (H. cinaedi) bacteremia; however, few reports have discussed the features of this condition in healthy individuals.

PATIENTS AND METHODS

A retrospective observational study was conducted at a Japanese tertiary care hospital to assess the clinical features of community-acquired H. cinaedi. All patients in whom H. cinaedi was isolated between January 2009 and March 2014 were identified from the hospital database.

RESULTS

Of the 28 patients included in the study, 12 had community-acquired H. cinaedi bacteremia. The most common clinical feature was cellulitis (n = 17). However, nearly half of the patients with healthcare-associated or nosocomial-associated bacteremia displayed no symptoms with the exception of fever. Most patients were successfully treated with a 14-day regime of third-generation cephalosporins or tetracycline.

CONCLUSIONS

Our results show that H. cinaedi infections are quite common in immunocompetent community-dwelling individuals.

Preterm labor and neonatal sepsis caused by intrauterine Helicobacter cinaedi infection

Helicobacter cinaedi is a rare pathogen but known to cause bacteremia, cellulitis and enterocolitis. Recently, cases of involving various organs are increasingly reported such as endocarditis, meningitis, and kidney cyst infection. We report a case of intrauterine H. cinaedi infection leading preterm birth and neonatal sepsis. A 29-year-old pregnant women who was no underlying disease hospitalized due to threatened preterm labor at 22 weeks of gestation. Clinical findings showed uterine tenderness, fever, leukocytosis and elevated C-reactive protein. H. cinaedi was isolated from amniotic fluid obtained by transabdominal amniocentesis. We diagnosed as intrauterine H. cinaedi infection and administered intravenous ampicillin followed by oxytocin to terminate pregnancy. A live 446 g male infant was delivered. The patient was no signs of infection throughout postpartum course and discharged on post-delivery day 5. The neonate was admitted in neonatal intensive care unit and administered ampicillin and amikacin. H. cinaedi was isolated from umbilical cord blood culture. He has no signs of infection on day 5 but died from uncontrollable hyperglycemia and ketoacidosis on 15 days of age. H. cinaedi can cause intrauterine infection during pregnancy and lead preterm labor and neonatal sepsis.

Vertebral Osteomyelitis Caused by Helicobacter cinaedi

Helicobacter cinaedi causes bacteremia, cellulitis, and gastroenteritis. We report the first case of vertebral osteomyelitis caused by H. cinaedi in an elderly man with low back pain and fever. The pathogen was detected in blood and lumbar disc, and the infection was successfully treated with oral doxycycline for 11 weeks.

Helicobacter cinaedi induced typhlocolitis in Rag-2-deficient mice

BACKGROUND

Helicobacter cinaedi, an enterohepatic helicobacter species (EHS), is an important human pathogen and is associated with a wide range of diseases, especially in immunocompromised patients. It has been convincingly demonstrated that innate immune response to certain pathogenic enteric bacteria is sufficient to initiate colitis and colon carcinogenesis in recombinase-activating gene (Rag)-2-deficient mice model. To better understand the mechanisms of human IBD and its association with development of colon cancer, we investigated whether H. cinaedi could induce pathological changes noted with murine enterohepatic helicobacter infections in the Rag2(-/-) mouse model.

MATERIALS AND METHODS

Sixty 129SvEv Rag2(-/-) mice mouse were experimentally or sham infected orally with H. cinaedi strain CCUG 18818. Gastrointestinal pathology and immune responses in infected and control mice were analyzed at 3, 6 and 9 months postinfection (MPI). H. cinaedi colonized the cecum, colon, and stomach in infected mice.

RESULTS

H. cinaedi induced typhlocolitis in Rag2(-/-) mice by 3 MPI and intestinal lesions became more severe by 9 MPI. H. cinaedi was also associated with the elevation of proinflammatory cytokines, interferon-γ, tumor-necrosis factor-α, IL-1β, IL-10; iNOS mRNA levels were also upregulated in the cecum of infected mice. However, changes in IL-4, IL-6, Cox-2, and c-myc mRNA expressions were not detected.

CONCLUSIONS

Our results indicated that the Rag2(-/-) mouse model will be useful to continue investigating the pathogenicity of H. cinaedi, and to study the association of host immune responses in IBD caused by EHS.

Pararenal Lymphatic Cyst Infection Caused by Helicobacter cinaedi

A 43-year-old man was referred to our hospital for an acute-onset fever and left flank pain. He had been previously diagnosed with lymphangioma, and abdominal computed tomography showed pararenal cysts with fat stranding around the left kidney, of which infection was subsequently confirmed on magnetic resonance imaging. Gram-negative spiral bacilli were isolated from two sets of blood cultures, and Helicobacter cinaedi was identified using 16S rRNA sequencing. The patient was successfully treated with ceftriaxone therapy without recurrence. A multilocus sequence typing analysis indicated the current H. cinaedi strain differed from previous strains isolated in Japan.

Helicobacter cinaedi-associated Vertebral Osteomyelitis in an Immunocompetent Patient

A 56-year-old previously healthy man was hospitalized due to a 10-day history of neck pain and an elevated C-reactive protein level. Gram-negative spiral bacilli were isolated from his blood, and Helicobacter cinaedi was confirmed using 16S rRNA sequencing. The infectious focus was not identified by initial cervical magnetic resonance imaging (MRI); however, repeated MRI demonstrated prominent high signal intensity in the entire region of the C6-C7 vertebrae and C6/C7 disc space. Furthermore, fluorodeoxyglucose-positron emission tomography/computed tomography showed no significant uptake, other than in the C6-C7 region. The patient was successfully treated with ceftriaxone for six weeks without sequelae.

First case of infective endocarditis caused by Helicobacter cinaedi

BACKGROUND

Up to 20% of all infective endocarditis are blood culture-negative and therefore a diagnostic challenge. Here we present the case of an infective endocarditis due to Helicobacter cinaedi finally diagnosed using different molecular methods. This highly fastidious gram-negative spiral rod is increasingly recognized as a human pathogen, above all in immunocompromised patients. So far H. cinaedi has been associated with bacteremia, cellulitis, arthritis and meningitis.

CASE PRESENTATION

A 71-year-old man presented with fever and progressive dyspnea for weeks. He was immunocompromised by long-term steroid therapy. As one major and two minor Duke's criteria (vegetation, fever and aortic valve stenosis as predisposition) were present, an infective endocarditis was suspected and an empiric therapy with amoxicillin/clavulanic acid and gentamicin was established. The persistent severe aortic regurgitation resulted in a valve replacement. Histological evaluation of the aortic valve showed a polypous-ulcerative endocarditis. Gram stain and culture remained negative. Broad-range bacterial PCR targeting the 16S rRNA gene on the biopsy of the aortic valve identified H. cinaedi as the causative agent. The antibiotic therapy was simplified accordingly to ceftriaxone and gentamicin with a recommended duration of 6 weeks. Ten days after valve replacement the patient was discharged. To complete our molecular finding, we sequenced nearly the complete 16S rRNA gene (accession number KF914917) resulting in 99.9% identity with H. cinaedi reference sequences. Based on this result, 2 species-specific PCR tests amplifying part of the ctd gene were established and applied to the valve specimen. The 2 PCRs confirmed H. cinaedi. In addition, we analyzed stool, urine and saliva from the patient using H. cinaedi PCR. The fecal and urine specimen showed a positive signal, saliva was PCR-negative.

CONCLUSION

We identified H. cinaedi as causative agent of a culture-negative endocarditis in an immunocompromised patient using broad-range and specific PCR. In addition to 2 cases from Japan presented on international meetings in 2010 and 2013, our case report shows that H. cinaedi should be recognized as additional causative organism of infective endocarditis. The use of molecular diagnostic techniques proved to be a powerful complement for the detection of blood culture-negative infective endocarditis.

Gastric and enterohepatic helicobacters other than Helicobacter pylori

During the past year, research on non-Helicobacter pylori species has intensified. H. valdiviensis was isolated from wild birds, and putative novel species have been isolated from Bengal tigers and Australian marsupials. Various genomes have been sequenced: H. bilis, H. canis, H. macacae, H. fennelliae, H. cetorum, and H. suis. Several studies highlighted the virulence of non-H. pylori species including H. cinaedi in humans and hyperlipidemic mice or H. macacae in geriatric rhesus monkeys with intestinal adenocarcinoma. Not surprisingly, increased attention has been paid to the position of Helicobacter species in the microbiota of children and animal species (mice, chickens, penguins, and migrating birds). A large number of experimental studies have been performed in animal models of Helicobacter induced typhlocolitis, showing that the gastrointestinal microbial community is involved in modulation of host pathways leading to chronic inflammation. Animal models of H. suis, H. heilmannii, and H. felis infection have been used to study the development of severe inflammation-related pathologies, including gastric MALT lymphoma and adenocarcinoma.

Clinical and bacteriological characteristics of Helicobacter cinaedi infection

Helicobacter cinaedi was first isolated from rectal cultures from homosexual men in 1984. In the 1980s to mid 1990s, the microorganism was mainly isolated from samples from homosexual men or immunocompromised patients; however, during the last two decades, H. cinaedi has been isolated from immunocompromised and from immunocompetent individuals worldwide. In Japan, the isolation of this microorganism was first reported in 2003. Since then, many cases have been reported in hospitals across the country. Despite many reports, the etiological properties and pathogenicity of H. cinaedi remain elusive; however, we are increasingly able to recognize some of the features and the clinical relevance of infection. In particular, a long incubation period is essential for detection in an automatic blood culture system and many of the recent isolates are resistant to both macrolides and quinolones. Furthermore, there is an association between infection and severe or chronic illnesses, such as meningitis or arteriosclerosis, in addition to mild diseases such as fever, abdominal pain, gastroenteritis, proctitis, diarrhea, erysipelas, cellulitis, arthritis, and bacteremia. In this review, we introduce the current knowledge and our latest findings relating to H. cinaedi.