Presence of periaortic gas in Clostridium septicum-infected aortic aneurysm aids in early diagnosis: a case report and systematic review of the literature

Genome sequence of Clostridium septicum strain WW106, isolated from influent wastewater at a research center with multiple-species research animal facilities

Clostridium septicum is an anaerobic Gram-positive rod-shaped bacterial pathogen known as a lethal causative agent of progressive gas gangrene in animals and humans. We report the 3.43-Mbp genome sequence of C. septicum strain WW106, isolated from influent wastewater at a research center with multiple-species laboratory animal facilities.

A rare case of mycotic aortic aneurysm with Clostridium perfringens culture

Key Clinical Message

As only early diagnosis, prompt surgical intervention, and appropriate antibiotic therapy can decrease clostridial MAA mortality rate; keeping in mind a broad differential diagnosis in a patient with sepsis and unusual vascular symptoms is important.

Abstract

Mycotic aortic aneurysm (MAA) is an infrequent but very consequential condition characterized by the pathological disruption of the aorta due to infection. Clostridium perfringens is a bacterium that falls under the taxonomic classification of the genus Clostridium. Although mycotic aneurysm is often not commonly linked with this infection, there are instances when it may function as a causative agent for MAA. Timely diagnosis and thorough therapeutic techniques, including surgical intervention and quick administration of appropriate antibiotics, can potentially reduce the mortality rate associated with clostridial MAA. In this study, we presented a clinical report detailing the diagnosis of a mycotic aneurysm caused by C. perfringens in the thoracic aorta in a 66-year-old male patient with a history of diabetes mellitus and a recent prostate biopsy. Furthermore, we discussed the surgical approach and overall management strategy to address this case.

Decisive diagnostic clue for infectious abdominal aortic aneurysm caused by Arthrobacter russicus in a diabetic elderly woman with renal dysfunction: A case report and literature review

Infectious aortic aneurysm (IAA) can be a rare but potentially fatal sequela of infectious inflammatory disease of the aortic wall with a high incidence of rupture. The definitive diagnosis is based on vascular imaging of the aneurysm using contrast-enhanced computed tomography (CE-CT) and identification of the causative microorganism from positive blood cultures (BCs). However, IAA remains extremely difficult to diagnose and treat in patients with prior antimicrobial treatment or with renal dysfunction. Here we describe a case of an 85-year-old woman with IAA caused by Arthrobacter russicus presenting with abdominal pain and fever that was initially diagnosed as a presumptive urinary tract infection and treated with empiric antimicrobial therapy. However, persistent abdominal pain with increased serological inflammation necessitated further evaluation. Unenhanced multimodality imaging considering the renal dysfunction revealed infectious aortitis of the infrarenal abdominal aorta, together with the initial culture results, leading to the tentative diagnosis of Klebsiella pneumoniae aortitis. Thereafter, serial monitoring with unenhanced magnetic resonance angiography (MRA) using thin-slab maximum intensity projection (TS-MIP) revealed acute aortic expansion strongly suggestive of a pseudoaneurysm that was successfully treated with early surgical repair under adequate infection control. Despite negative Gram staining and tissue culture results for the excised aortic wall, a definitive diagnosis of IAA secondary to A. russicus rather than K. pneumoniae was finally made by confirming the histologic findings consistent with IAA and the identification of A. russicus 16S rRNA on the resected aortic wall. The patient also developed a vascular graft infection during the postoperative course that required long-term systemic antimicrobial therapy. This case highlights the value of unenhanced MRA in the early detection of IAA in patients with renal dysfunction and the importance of a molecular diagnosis for identifying the causative microorganism in cases of culture- or tissue-negative IAA.

Emphysematous Aortitis due to Klebsiella Pneumoniae in a Patient With Poorly Controlled Diabetes Mellitus

Patients with poorly controlled diabetes mellitus and an infectious source can be predisposed to infectious aortitis.

First Comparative Analysis of Clostridium septicum Genomes Provides Insights Into the Taxonomy, Species Genetic Diversity, and Virulence Related to Gas Gangrene

Clostridium septicum is a Gram-positive, toxin-producing, and spore-forming bacterium that is recognized, together with C. perfringens, as the most important etiologic agent of progressive gas gangrene. Clostridium septicum infections are almost always fatal in humans and animals. Despite its clinical and agricultural relevance, there is currently limited knowledge of the diversity and genome structure of C. septicum. This study presents the complete genome sequence of C. septicum DSM 7534T type strain as well as the first comparative analysis of five C. septicum genomes. The taxonomy of C. septicum, as revealed by 16S rRNA analysis as well as by genomic wide indices such as protein-based phylogeny, average nucleotide identity, and digital DNA–DNA hybridization indicates a stable clade. The composition and presence of prophages, CRISPR elements and accessory genetic material was variable in the investigated genomes. This is in contrast to the limited genetic variability described for the phylogenetically and phenotypically related species Clostridium chauvoei. The restriction-modification (RM) systems between two C. septicum genomes were heterogeneous for the RM types they encoded. C. septicum has an open pangenome with 2,311 genes representing the core genes and 1,429 accessory genes. The core genome SNP divergence between genome pairs varied up to 4,886 pairwise SNPs. A vast arsenal of potential virulence genes was detected in the genomes studied. Sequence analysis of these genes revealed that sialidase, hemolysin, and collagenase genes are conserved compared to the α-toxin and hyaluronidase genes. In addition, a conserved gene found in all C. septicum genomes was predicted to encode a leucocidin homolog (beta-channel forming cytolysin) similar (71.10% protein identity) to Clostridium chauvoei toxin A (CctA), which is a potent toxin. In conclusion, our results provide first, valuable insights into strain relatedness and genomic plasticity of C. septicum and contribute to our understanding of the virulence mechanisms of this important human and animal pathogen.

Clostridium septicum-infected Stanford type A acute aortic dissection: a case report

Background

Thoracic aortitis caused by Clostridium septicum is a rare infection with a strong association with malignancy and high mortality rate when left untreated. We report a case of surgical treatment for Stanford type A acute aortic dissection in a patient with C. septicum sepsis and thoracic aortitis.

Case presentation

A 63-year-old hypertensive man with rheumatoid arthritis presented with general malaise and diagnosed with C. septicum-infected aortitis with sepsis. On the 5th day of hospitalization, Stanford type A acute aortic dissection developed with severe aortic regurgitation. The patient underwent emergent surgical treatment successfully with excision of the infected ascending aorta and aortic root followed by replacement using a composite graft, followed by diagnosis of sigmoid colon cancer 7 months after aortic surgery. He was scheduled to undergo elective colon surgery.

Conclusions

C. septicum aortitis can progress quickly, causing aneurysm or dissection. Therefore, in a patient with C. septicum aortitis, prompt surgical in situ graft replacement should be performed to debride the infected vascular lesions. Further investigations for gastrointestinal and hematological malignancies as a source of C. septicum should be also conducted.

Clostridium septicum-infected aortic aneurysm or graft is a deadly diagnosis

BACKGROUND

Clostridium septicum is an anaerobic, motile, spore-forming, toxin-producing gram-positive bacillus that can lead to rapidly progressive gas gangrene due to the release of alpha toxin. Aortic aneurysm secondary to C. septicum infection is a rare condition with 60 cases reported in the literature; however, we have recently treated several patients with the condition in our large tertiary care and aortic center.

METHODS

Blood and tissue culture results collected between January 2005 and January 2018 and maintained in the microbiology laboratory database at the Cleveland Clinic were reviewed to identify those with C. septicum reported. Each was reviewed to determine radiographic or histopathologic correlation with aortic disease.

RESULTS

Seven cases of C. septicum aortitis were reviewed. Underlying malignant disease was found in four cases and a history of remote malignant disease in one case. The most common location for infection was the infrarenal abdominal aorta. Vascular surgery had previously been performed in three of the cases. Five of the seven patients underwent operative repair. All patients were treated with β-lactam antibiotics. The two patients who did not undergo an operation died, which is consistent with the 100% mortality described in the literature. Of the five patients who underwent an operation, there was only one documented survivor and one was lost to follow-up.

CONCLUSIONS

In the largest reported case series, only a small percentage of patients with C. septicum-infected aortic aneurysms survived >1 year. In the patients described, those who did not receive an operation had 100% mortality. Earlier recognition and prompt operation with appropriate antimicrobial therapy are needed to improve the outcome of patients diagnosed with this rare infection.

Radiographic Evidence of Soft-Tissue Gas 14 Days After Total Knee Arthroplasty Is Predictive of Early Prosthetic Joint Infection

OBJECTIVE. The diagnosis of early prosthetic joint infection (PJI)-defined as within 6 weeks after a total knee arthroplasty (TKA)-can be difficult because of expected postsurgical changes and elevated inflammatory markers. The role of radiographic evaluation in this situation carries unclear clinical significance. This study had three primary aims: first, to determine when soft-tissue gas is no longer an expected postoperative radiographic finding; second, to determine whether soft-tissue gas is predictive of early PJI; and, third, to determine whether the presence of soft-tissue gas correlates with specific patient characteristics and microbiology culture results. MATERIALS AND METHODS. This retrospective study was of patients who underwent TKA from 2008 to 2018 with available imaging between 5 days and 6 weeks after TKA and no interval intervention before imaging. All confirmed early PJIs were included (n = 24 cases; 15 patients). For comparison, patients who underwent TKA but did not have a PJI (n = 180 cases; 150 patients) were selected randomly. Radiographs were reviewed by two readers. A two-tailed p < 0.05 was considered significant. RESULTS. Soft-tissue gas was identified on postoperative radiography of 13 of 24 (54.2%) cases (mean ± standard error of the mean [SEM], 28.3 ± 2.3 days after TKA) with early PJI and four of 180 (2.2%) cases (mean ± SEM, 15.3 ± 7.3 days after TKA) without PJI (p < 0.0001; odds ratio, 52.0 [95% CI, 14.7-156.9]). The presence of soft-tissue gas on radiography 14 days after TKA had a sensitivity of 0.54 (95% CI, 0.35-0.72) and specificity of 0.99 (95% CI, 0.97-1.00) for early PJI. Staphylococcus species were the dominant organisms; cases with soft-tissue gas showed a wider variety of microbiology species (p < 0.01). CONCLUSION. Postoperative soft-tissue gas present on radiography performed 14 days or more after TKA is predictive of early PJI and is associated with a wider spectrum of microorganisms.

Emphysematous Aortitis due to Clostridium septicum in an 89-Year-Old Female with Ileus

Emphysematous aortitis is a rare but lethal form of infectious vasculitis. This condition was found incidentally on computed tomography of the chest during the evaluation of a patient presenting with pneumonia coincident with adynamic ileus. The patient did not have a history of malignancy. While colon cancer could not be ruled out, it is possible that ileus may have contributed to or resulted in bacterial translocation in this case. Appropriate investigations and empirical therapy against Clostridium septicum should be initiated in the presence of clinical and radiological findings suggestive of emphysematous aortitis.

Clostridium septicum arthroplasty infection: beware of occult aortitis and malignancy

Introduction

The Clostridia species are responsible for life-threatening conditions such as tetanus, botulism and gas gangrene. Clostridium septicum is a rare cause of clinical infection, accounting for less than 1% of blood culture samples that test positive for Clostridia. However, C. septicum bacteraemia is associated with greater than 60% mortality and in over 80% of cases is associated with an underlying malignancy.

Case presentation

We present a review of the literature and the first case of an acute arthroplasty infection and concurrent infective aortitis caused by this organism in the absence of an identified underlying malignancy. Early diagnosis and multi-disciplinary input resulted in the patient surviving a rare and potentially fatal infective aortitis and septic arthritis.

Conclusion

This case demonstrates the importance of early systemic investigation to exclude occult infective aortitis in C. septicum infection. The key role of multi-disciplinary input into the management of this often fatal infection is also discussed along with the requirement to exclude occult gastrointestinal and haematological malignancy.