Helicobacter cinaedi infection of abdominal aortic aneurysm, Japan

CAIP-Induced ROS Production Contributes to Sustaining Atherosclerotic Process Associated with Helicobacter cinaedi Infection through Macrophages and Endothelial Cells Activation

Several lines of evidence have linked the intestinal bacterium Helicobacter cinaedi with the pathogenesis of atherosclerosis, identifying the Cinaedi Antigen Inflammatory Protein (CAIP) as a key virulence factor. Oxidative stress and inflammation are crucial in sustaining the atherosclerotic process and oxidized LDL (oxLDL) uptake. Primary human macrophages and endothelial cells were pre-incubated with 10 µM diphenyl iodonium salt (DPI) and stimulated with 20 µg/mL CAIP. Lectin-like oxLDL receptor (LOX-1) expression was evaluated by FACS analysis, reactive oxygen species (ROS) production was measured using the fluorescent probe H2DCF-DA, and cytokine release was quantified by ELISA assay. Foam cells formation was assessed by Oil Red-O staining, and phosphorylation of p38 and ERK1/2 MAP kinases and NF-κB pathway activation were determined by Western blot. This study demonstrated that CAIP triggered LOX-1 over-expression and increased ROS production in both macrophages and endothelial cells. Blocking ROS abrogated LOX-1 expression and reduced LDL uptake and foam cells formation. Additionally, CAIP-mediated pro-inflammatory cytokine release was significantly affected by ROS inhibition. The signaling pathway induced by CAIP-induced oxidative stress led to p38 MAP kinase phosphorylation and NF-κB activation. These findings elucidate the mechanism of action of CAIP, which heightens oxidative stress and contributes to the atherosclerotic process in H. cinaedi-infected patients.

In situ repair or reconstruction of the abdominal aorta-iliac artery by autologous fascia-peritoneum with posterior rectus sheath for the treatment of the infected abdominal aortic and iliac artery aneurysms: A case series and literature review

Background

Infected abdominal aortic and iliac artery aneurysms are considered acute and severe diseases with insidious onset, rapid development, and high mortality in vascular surgery. Currently, there is no better treatment, either anatomic or extra-anatomical repair.

Case presentation

From February 2018 to April 2022, 7 patients with infected abdominal aortic and iliac artery aneurysms did not have sufficient autologous venous material for repair. With the consent of the Ethics Committee of the hospital, it uses the autologous peritoneal fascial tissue with rectus sheath to repair or reconstruct the infected vessels in situ. There were 5 cases of infected abdominal aortic aneurysm, 1 case of an infected common iliac aneurysm, and 1 case of the infected internal iliac aneurysm. Aortoduodenal fistula was found in 3 cases, all of them were given duodenal fistula repair and gastrojejunostomy and cholecystostomy. Three cases of infected abdominal aortic aneurysms were repaired with the autologous peritoneal fascial tissue patch, and 2 cases of infected abdominal aortic aneurysms were reconstructed by the autologous peritoneal fascial tissue suture to bifurcate graft in situ, the autologous peritoneal fascial tissue suture reconstructed the rest 2 cases of infected iliac aneurysm to tubular graft in situ. It was essential that Careful debridement of all infected tissue and adequate postoperative irrigation and drainage. Antibiotics were administered perioperatively, and all patients were subsequently treated with long-term antibiotics based on bacterial culture and susceptibility results of infected tissues and blood. All 7 patients had underwent surgery successfully. But there were 2 cases died of anastomotic infection or massive hemorrhage after the operation, the other 5 cases survived. The follow-up time was 2–19 months. The enhanced CT of postoperation showed that the reconstructed arteries were smooth without obvious stenosis or expansion, and no abdominal wall hernia occurred.

Conclusion

In situ repair or reconstruction with autologous peritoneal fascial tissue with rectus sheath is a feasible treatment for the infected aneurysm patients without adequate autologous venous substitute, but it still needs long-term follow-up and a large sample to be further confirmed.

Infective Endocarditis with a Left Ventricular Pseudoaneurysm Caused by Proteus mirabilis: A Case Report

Infective endocarditis (IE) due to Proteus mirabilis is rare. Given that cases of IE complicated with a left ventricular pseudoaneurysm (LVP) caused by P. mirabilis have not been reported thus far, here we report a case of IE complicated with an LVP caused by P. mirabilis. An 83-year-old woman was admitted to our hospital for urinary tract infection, and P. mirabilis was detected in blood cultures. Transesophageal echocardiography and electrocardiogram-gated computed tomography revealed mitral regurgitation and a mass protruding from the mitral annulus on the dorsal side. We made a diagnosis of an LVP due to IE and performed mitral valve replacement and patch plasty of the mitral annulus. Thus, P. mirabilis can cause bloodstream infections and lead to IE, which may result in LVPs. <Learning objective: Proteus mirabilis commonly causes urinary tract infection in older adults and is also likely to cause bloodstream infections; however, it is rarely known to be the causative agent of infective endocarditis and left ventricular pseudoaneurysms. However, in clinical settings, clinicians should be aware that P. mirabilis can also cause IE with annular extension.>.

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.

Infected aortic aneurysm caused by Helicobacter cinaedi: case series and systematic review of the literature

Background

Helicobacter cinaedi is rarely identified as a cause of infected aneurysms; however, the number of reported cases has been increasing over several decades, especially in Japan. We report three cases of aortic aneurysm infected by H. cinaedi that were successfully treated using meropenem plus surgical stent graft replacement or intravascular stenting. Furthermore, we performed a systematic review of the literature regarding aortic aneurysm infected by H. cinaedi.

Case presentation

We present three rare cases of infected aneurysm caused by H. cinaedi in adults. Blood and tissue cultures and 16S rRNA gene sequencing were used for diagnosis. Two patients underwent urgent surgical stent graft replacement, and the other patient underwent intravascular stenting. All three cases were treated successfully with intravenous meropenem for 4 to 6 weeks.

Conclusions

These cases suggest that although aneurysms infected by H. cinaedi are rare, clinicians should be aware of H. cinaedi as a potential causative pathogen, even in immunocompetent patients. Prolonged incubation periods for blood cultures are necessary for the accurate detection of H. cinaedi.

Molecular epidemiologic and clinical analysis of Helicobacter cinaedi bacteremia in Japan

BACKGROUND

Helicobacter cinaedi is an important pathogen that causes bloodstream infections. Owing to the challenges in its culture and identification, its clinical and bacterial characteristics remain unknown. Our study aimed to investigate the molecular epidemiology and antimicrobial susceptibility of H cinaedi.

MATERIALS AND METHODS

From 2003 to 2016, we analyzed 16 non-repetitive H cinaedi strains, isolated from blood, at the medical hospital of Tokyo Medical and Dental University. Multilocus sequence typing was performed to analyze the genetic relationship across the different isolates. The minimum inhibitory concentrations (MIC) of antibiotics were determined by the agar dilution method.

RESULTS

The median age of subjects in this study was 61 years (range, 18-84 years). The most common risk factors included the use of steroids (75.0%) and immunosuppressant drugs (37.5%). In addition, the most common symptoms of H cinaedi bacteremia included colitis (37.5%) and cellulitis (31.3%). The infection recurred in three of seven cases (42.8%) that underwent antibiotic therapy for <10 days. The strains were classified into five sequence types (ST), of which, ST 10 (43.8%) and ST 4 (31.3%) were predominant. The MIC₉₀ values of amoxicillin, gentamycin, imipenem, ciprofloxacin, and clarithromycin were 4, 0.5, 0.25, 64, and 128 mg/L, respectively.

CONCLUSIONS

Since there is no recommended guideline yet for the choice or duration of antibiotic therapy and antimicrobial break points, our results suggested, for the first time, that prolonged antibiotic therapy, except with ciprofloxacin and clarithromycin, would be required to ensure resolution of symptoms and prevention of recurrence.

Abdominal Aortic Graft Infection Caused by stG485.0, ST29 Streptococcus dysgalactiae subsp. equisimilis

In recent years, the prevalence of invasive Streptococcus dysgalactiae subsp. equisimilis (SDSE) infections has increased gradually throughout the world, including Japan. Here, we report the case of an abdominal aortic graft infection caused by stG485.0, ST29 SDSE in an elderly patient with diabetes. The patient was an 86-year-old man who had undergone surgery 10 years ago for treating a non-infected abdominal aortic aneurysm using a bifurcated graft. He was referred to our hospital after being suspected of having an abdominal aortic graft infection based on computed tomography (CT) scans. He underwent surgery to drain the pus that had accumulated between the aneurysm and graft. Although blood cultures were negative, the surgical specimen culture was positive for a β-hemolytic group G streptococci, which was subsequently identified as SDSE using 16S ribosomal RNA sequencing. Genetic relationships deduced from emm and multilocus sequence typing revealed the isolate to be types stG485.0 and ST29, respectively. Although aortic aneurysm graft infection has a poor prognosis, we successfully rescued the patient through prompt surgery and identification of the responsible pathogen. This case indicates that attention must be paid toward possible SDSE infections in the field of vascular surgery.

A Case Report of Autosomal Dominant Polycystic Kidney Disease Under Peritoneal Dialysis With Cyst Infection and Culture-Positive Peritoneal Fluid

Background:

Cyst infection is a complication sometimes seen in patients with autosomal dominant polycystic kidney disease (ADPKD) and often shows through a positive blood culture. However, there have been no reports of ADPKD patients whose cyst infection propagate to peritoneal fluid leading to positive peritoneal fluid culture.

Case presentation:

A 74-year-old Japanese man with ADPKD under peritoneal dialysis (PD) was presented with left flank pain, fever, and chills at our hospital. He did not show any symptoms or signs suggestive of peritonitis. There were no elevated cell counts or polymorphonuclear leucocytes in his PD fluid. There were some complicated cysts found in computed tomography and magnetic resonance imaging examinations. We clinically diagnosed him as having a renal cyst infection rather than PD-related peritonitis. We initiated treatment by administering ceftriaxone with an immediate favorable response. As the possibility of accompanying prostatitis still remained, we switched to intravenous levofloxacin on the second day. On the 10th day, Helicobacter cinaedi was detected in 2 sets of blood culture as well as in PD fluid. We switched back to ceftriaxone and this treatment was entirely successful.

Conclusions:

This is the first report of H cinaedi cyst infection which propagates to peritoneal fluid in a patient with ADPKD.

Mutations in Genes Encoding Penicillin-Binding Proteins and Efflux Pumps Play a Role in β-Lactam Resistance in Helicobacter cinaedi

β-Lactams are often used to treat Helicobacter cinaedi infections; however, the mechanism underlying β-lactam resistance is unknown. In this study, we investigated β-lactam resistance in an H. cinaedi strain, MRY12-0051 (MICs of amoxicillin [AMX] and ceftriaxone [CRO], 32 and 128 μg/ml; obtained from human feces). Based on a comparative whole-genome analysis of MRY12-0051 and the CRO-susceptible H. cinaedi strain MRY08-1234 (MICs of AMX and CRO, 1 and 4 μg/ml; obtained from human blood), we identified five mutations in genes encoding penicillin-binding proteins (PBPs), including two in pbpA, one in pbp2, and two in ftsI Transformation and penicillin binding assays indicated that CRO resistance was mainly associated with mutations in pbpA; mutations in ftsI also led to increased resistance to AMX. Knocking out cmeB and cmeD, which encode resistance-nodulation-division-type efflux pump components, in H. cinaedi type strain CCUG18818 (AMX MIC, 4 to 8 μg/ml) resulted in 8- and 64-fold decreases, respectively, in the AMX MIC. Hence, MICs of AMX in H. cinaedi become similar to those of Helicobacter pylori isolates in the absence of cmeD In conclusion, the difference in susceptibility to β-lactams between H. pylori and H. cinaedi is explained by differences in efflux pump components. Mutations in pbpA are the primary determinant of high resistance to β-lactams in H. cinaedi.

Molecular diagnosis and characterization of a culture-negative mycotic aneurysm due to ST54 Haemophilus influenzae type b with PBP 3 alterations

Mycotic aneurysm is a rare but life-threatening disease that warrants an integrated therapeutic approach involving surgical intervention and prolonged antibiotic use. However, the causative organisms are often unidentified because antibiotics started empirically render blood and tissue cultures negative. Molecular diagnosis has been reported to be useful in such culture-negative cases. We report a case of a culture-negative mycotic aortic aneurysm due to Haemophilus influenzae, diagnosed by direct 16S rRNA polymerase chain reaction (PCR) and sequencing of the resected aneurysm tissue. PCR for serotype revealed type b, and PCR and sequencing of the ftsI gene revealed alterations in penicillin-binding protein 3, suggesting resistance to ampicillin. Multilocus sequence typing demonstrated that the isolate belonged to sequence type 54.

Bacteremia and Skin Infections in Four Patients Caused by Helicobacter-Like Organisms

Background

Enterohepatic Helicobacter-like organisms (HLO) have been recognized as causes of human infection since 1984, primarily as a cause of bacteremia and cellulitis in immunocompromised individuals, but the spectrum of illness due to HLO has expanded based on numerous reports from Japan.

Methods

We report 4 epidemiologically unrelated immunocompetent patients with HLO bacteremia diagnosed within a 2-year period. Three patients had cellulitis and 1 patient had unexplained fever. 16S ribosomal deoxyribonucleic acid (rDNA) sequence analysis of 2 isolates suggested that they were Helicobacter cinaedi, and whole-genome sequencing showed that they differed only slightly from reference strains.

Conclusions

We believe that this syndrome is more common than reported, but it is easily overlooked because the skin lesions resemble streptococcal cellulitis and respond very rapidly to β-lactam antibiotics, and the organism is difficult to isolate from the blood. All HLO in our series were isolated from blood using the ESP system and were not detected in 2 other widely used commercial blood culture systems.

The Helicobacter cinaedi antigen CAIP participates in atherosclerotic inflammation by promoting the differentiation of macrophages in foam cells

Recent studies have shown that certain specific microbial infections participate in atherosclerosis by inducing inflammation and immune reactions, but how the pathogens implicated in this pathology trigger the host responses remains unknown. In this study we show that Helicobacter cinaedi (Hc) is a human pathogen linked to atherosclerosis development since at least 27% of sera from atherosclerotic patients specifically recognize a protein of the Hc proteome, that we named Cinaedi Atherosclerosis Inflammatory Protein (CAIP) (n = 71). CAIP appears to be implicated in this pathology because atheromatous plaques isolated from atherosclerotic patients are enriched in CAIP-specific T cells (10%) which, in turn, we show to drive a Th1 inflammation, an immunopathological response typically associated to atherosclerosis. Recombinant CAIP promotes the differentiation and maintenance of the pro-inflammatory profile of human macrophages and triggers the formation of foam cells, which are a hallmark of atherosclerosis. This study identifies CAIP as a relevant factor in atherosclerosis inflammation linked to Hc infection and suggests that preventing and eradicating Hc infection could reduce the incidence of atherosclerosis.

Infected Thoracic Aortic Aneurysm Caused by Helicobacter cinaedi

The causative organism is not identified in some cases of infected aneurysms, a life-threatening condition. A 68-year-old man presented with chest/back pain and a 1-year history of intermittent fever and fatigue. Computed tomography revealed a thoracic aortic aneurysm. After several negative blood cultures, he was eventually diagnosed with an infected aneurysm caused by Helicobacter cinaedi via gene analysis of an aortic tissue specimen. As H. cinaedi is a low-virulence bacterium, infection with this pathogen should be suspected in cases of aortic aneurysms with unidentified causative organism and a long history of subjective symptoms. Detailed examinations, including polymerase chain reaction, should be conducted in such cases.

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.

First report of severe acute otitis media caused by Campylobacter rectus and review of the literature

Campylobacter rectus is a member of the human oral flora and is associated with periodontal disease. We report the first case of severe acute otitis media (AOM) due to C. rectus in a previous healthy 15-year-old boy, which was confirmed by 16S ribosomal RNA gene sequencing. C. rectus is a possible causative pathogen of AOM.

Infected Abdominal Aortic Aneurysm with Helicobacter cinaedi

Helicobacter cinaedi is a rare human pathogen which has various clinical manifestations such as cellulitis, bacteremia, arthritis, meningitis, and infectious endocarditis. We report an abdominal aortic aneurysm infected with Helicobacter cinaedi, treated successfully with surgical repair and long-term antimicrobial therapy.

An Infected Abdominal Aortic Aneurysm Caused by Helicobacter cinaedi

We present a rare case of an infected abdominal aortic aneurysm due to Helicobacter cinaedi that was detected by blood culture. A 79-year-old man with lumbago and left lower quadrant pain was admitted for the treatment of an infected abdominal aortic aneurysm. H. cinaedi was isolated from a blood culture, which was obtained on admission. The aneurysm was successfully treated with antibiotic therapy, aneurysmectomy, debridement, replacement of a bifurcated Dacron prosthesis, and omental wrapping. Our present case suggests that H. cinaedi should be considered as the causative agent of an infected aortic aneurysm.

The Other Helicobacters

In the past year, a substantial number of (putative) novel Helicobacter species have been described, including Helicobacter himalayensis colonizing the Himalayan marmot and Helicobacter apodemus, colonizing the Korean striped field mouse. In addition, a putative novel gastric Helicobacter species was identified in wild gorillas and chimpanzees, for which the name "Candidatus H. homininae" was proposed. A high incidence of gastric non-H. pylori Helicobacter infection was described in China and multiple case reports have described the involvement of enterohepatic Helicobacter species, especially Helicobacter cinaedi, in a wide range of diseases. Several studies in rodent models further elucidated the mechanisms underlying the development of gastric mucosa-associated lymphoid tissue lymphoma during infection with gastric non-H. pylori Helicobacters. The effects of infection with gastric Helicobacters on the development of neuroinflammation were investigated and several enterohepatic Helicobacter species were shown to affect the composition of the gut microbiota, to influence vaccine efficiency as well as the progression of cancer in distant sites of the body.