Corynebacterium diphtheriae endocarditis: a case series and review of the treatment approach

Cluster of Nontoxigenic Corynebacterium diphtheriae Infective Endocarditis and Rising Background C. diphtheriae Cases-Seattle, Washington, 2020-2023

BACKGROUND

Nontoxigenic Corynebacterium diphtheriae, often associated with wounds, can rarely cause infective endocarditis (IE). Five patients with C. diphtheriae IE were identified within 12 months at a Seattle-based hospital system. We reviewed prior C. diphtheriae-positive cultures to determine if detections had increased over time and evaluated epidemiologic trends.

METHODS

We conducted a formal electronic health record search to identify all patients aged ≥18 years with C. diphtheriae detected in a clinical specimen (ie, wound, blood, sputum) between 1 September 2020 and 1 April 2023. We collected patient demographics, housing status, comorbidities, substance-use history, and level of medical care required at detection. We extracted laboratory data on susceptibilities of C. diphtheriae isolates and on other pathogens detected at the time of C. diphtheriae identification.

RESULTS

Between 1 September 2020 and 1 April 2023, 44 patients (median age, 44 years) had a C. diphtheriae-positive clinical culture, with most detections occurring after March 2022. Patients were predominantly male (75%), White (66%), unstably housed (77%), and had a lifetime history of injecting drugs (75%). Most C. diphtheriae-positive cultures were polymicrobial, including wound cultures from 36 (82%) patients and blood cultures from 6 (14%) patients, not mutually exclusive. Thirty-four patients (77%), including all 5 patients with C. diphtheriae IE, required hospital admission for C. diphtheriae or a related condition. Of the 5 patients with IE, 3 died of IE and 1 from COVID-19.

CONCLUSIONS

Findings suggest a high-morbidity outbreak disproportionately affecting patients who use substances and are unstably housed.

Insights of OxyR role in mechanisms of host-pathogen interaction of Corynebacterium diphtheriae

Corynebacterium diphtheriae, the leading causing agent of diphtheria, has been increasingly related to invasive diseases, including sepsis, endocarditis, pneumonia, and osteomyelitis. Oxidative stress defense is required not only for successful growth and survival under environmental conditions but also in the regulation of virulence mechanisms of human pathogenic species, by promoting mucosal colonization, survival, dissemination, and defense against the innate immune system. OxyR, functioning as a negative and/or positive transcriptional regulator, has been included among the major bacterial coordinators of antioxidant response. OxyR was first reported as a repressor of catalase expression in C. diphtheriae. However, the involvement of OxyR in C. diphtheriae pathogenesis remains unclear. Accordingly, this work aimed to investigate the role of OxyR in mechanisms of host-pathogen interaction of C. diphtheriae through the disruption of the OxyR of the diphtheria toxin (DT)-producing C. diphtheriae CDC-E8392 strain. The effects of OxyR gene disruption were analyzed through interaction assays with human epithelial cell lines (HEp-2 and pneumocytes A549) and by the induction of experimental infections in Caenorhabditis elegans nematodes and Swiss Webster mice. The OxyR disruption exerted influence on NO production and mechanism accountable for the expression of the aggregative-adherence pattern (AA) expressed by CDC-E8392 strain on human epithelial HEp-2 cells. Moreover, invasive potential and intracytoplasmic survival within HEp-2 cells, as well as the arthritogenic potential in mice, were found affected by the OxyR disruption. In conclusion, data suggest that OxyR is implicated in mechanisms of host-pathogen interaction of C. diphtheriae.

A Rare Case Report of Non-toxigenic Corynebacterium diphtheriae Bloodstream Infection in an Uncontrolled Diabetic With Peripheral Vascular Disease

Corynebacterium diphtheriae usually causes respiratory diphtheria, which is considered as a disease of toxemia but never bacteremia. Over the last few decades, cutaneous diphtheria has been increasingly reported owing to the emergence of the non-toxigenic strain, which causes locally necrotic and ulcerative lesions. Bacteremia is very rare, but the existing evidence in the literature suggests that the organism can rarely cause invasive infections such as septicemia, endocarditis, and osteoarthritis. Here, we present a rare case of C. diphtheriae causing bloodstream infections in an elderly diabetic with peripheral vascular disease, which was diagnosed incidentally on routine blood culture owing to automated identification systems viz matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) confirmed with conventional methods, and susceptibility was performed using automated VITEK 2 system (BioMérieux, Marcy-l'Étoile, France), which has aided in the timely management.

Molecular and Epidemiological Characterization of Toxigenic and Nontoxigenic Corynebacterium diphtheriae, Corynebacterium belfantii, Corynebacterium rouxii, and Corynebacterium ulcerans Isolates Identified in Spain from 2014 to 2019

This study examines the microbiological and epidemiological characteristics of toxigenic and nontoxigenic Corynebacterium isolates submitted to the national reference laboratory in Spain, between 2014 and 2019, in order to describe the current situation and improve our knowledge regarding these emerging pathogens. Epidemiological information was extracted from the Spanish Surveillance System. Microbiological and molecular characterization was carried out using phenotypic methods, multilocus sequence typing (MLST), whole-genome sequencing (WGS), and core genome MLST (cgMLST). Thirty-nine isolates were analyzed. Twenty-one isolates were identified as Corynebacterium diphtheriae (6 toxigenic), 14 as C. belfantii, 4 as C. ulcerans (3 toxigenic), and 1 as C. rouxii One C. diphtheriae isolate was identified as nontoxigenic tox gene bearing (NTTB). Ages of patients ranged from 1 to 89 years, with 10% (3/30) of nontoxigenic and 22% (2/9) of toxigenic isolates collected from children less than 15 years. Twenty-five of the patients were males (17/30 in nontoxigenic; 8/9 in toxigenic). MLST identified 28 sequence types (STs), of which 7 were described for the first time in Spain. WGS analysis showed that 10 isolates, including 3 toxigenic isolates, harbored a variety of antibiotic resistance genes in addition to the high prevalence of penicillin resistance phenotypically demonstrated. Phylogenetic analysis revealed one cluster of isolates from family members. Risk information was available for toxigenic isolates (9/39); 3 patients reported recent travels to countries of endemicity and 3 had contact with cats/dogs. One unvaccinated child with respiratory diphtheria had a fatal outcome. Including nontoxigenic Corynebacterium infections in disease surveillance and using WGS could further improve current surveillance.

Non-toxigenic Corynebacterium diphtheriae infective endocarditis with embolic events: a case report

Background

Corynebacterium diphtheriae (C. diphtheriae) infections, usually related to upper airways involvement, could be highly invasive. Especially in developing countries, non-toxigenic C. diphtheriae strains are now emerging as cause of invasive disease like endocarditis. The present case stands out for reinforcing the high virulence of this pathogen, demonstrated by the multiple systemic embolism and severe valve deterioration. It also emphasizes the importance of a coordinated interdisciplinary work to address all these challenges related to infectious endocarditis.

Case presentation

A 21-year-old male cocaine drug abuser presented to the emergency department with a 1-week history of fever, asthenia and dyspnea. His physical examination revealed a mitral systolic murmur, signs of acute arterial occlusion of the left lower limb, severe arterial hypotension and acute respiratory failure, with need of vasoactive drugs, orotracheal intubation/mechanical ventilation, empiric antimicrobial therapy and emergent endovascular treatment. The clinical suspicion of acute infective endocarditis was confirmed by transesophageal echocardiography, demonstrating a large vegetation on the mitral valve associated with severe valvular regurgitation. Abdominal ultrasound was normal with no hepatic, renal, or spleen abscess. Serial blood cultures and thrombus culture, obtained in the vascular procedure, identified non-toxigenic C. diphtheriae, with antibiotic therapy adjustment to monotherapy with ampicillin. Since the patient had a severe septic shock with sustained fever, despite antimicrobial therapy, urgent cardiac surgical intervention was planned. Anatomical findings were compatible with an aggressive endocarditis, requiring mitral valve replacement for a biological prosthesis. During the postoperative period, despite an initial clinical recovery and successfully weaning from mechanical ventilation, the patient presented with a recrudescent daily fever. Computed tomography of the abdomen revealed a hypoattenuating and extensive splenic lesion suggestive of abscess. After sonographically guided bridging percutaneous catheter drainage, surgical splenectomy was performed. Despite left limb revascularization, a forefoot amputation was required due to gangrene. The patient had a good clinical recovery, fulfilling 4-weeks of antimicrobial treatment.

Conclusion

Despite the effectiveness of toxoid-based vaccines, recent global outbreaks of invasive C. diphtheriae infectious related to non-toxigenic strains have been described. These infectious could be highly invasive as demonstrated in this case. Interdisciplinary work with an institutional “endocarditis team” is essential to achieve favorable clinical outcomes in such defiant scenarios.

Corynebacterium diphtheriae bloodstream infection: the role of antitoxin

A 65-year-old male patient presented with fever, fast atrial fibrillation and frank haematuria on return to Ireland from travel in East Africa. He had a systolic murmur leading to a clinical suspicion of endocarditis. He had no specific clinical features of diphtheria. Blood cultures were taken and empiric therapy commenced with benzylpenicillin, vancomycin and gentamicin. Corynebacterium diphtheriae was detected on blood culture. The isolate was submitted to a reference laboratory for evaluation of toxigenicity. While initially there was concern regarding the possibility of myocarditis, a clinical decision was made not to administer diphtheria antitoxin in the absence of clinical features of respiratory diphtheria, in the presence of invasive infection and with presumptive previous immunisation. There is no specific guidance on the role of antitoxin in this setting. The issue is not generally addressed in previous reports of C. diphtheriae blood stream infection.

Corynebacterium diphtheriae-infective endocarditis in a patient with an atrial septal defect closure device

An 18-year-old woman presented to our institution with fever, bilateral flank pain, headache and photophobia. She had a previous atrial septal defect (ASD) closure device inserted at the age of 9 years. Blood cultures on admission were positive for Corynebacterium diphtheriae, and transoesophageal echocardiogram (TOE) revealed an echodensity associated with the ASD closure device, most consistent with a vegetation. She was treated for infective endocarditis with 6 weeks of intravenous benzylpenicillin, and follow-up TOE showed resolution of the echodensity. To our knowledge, no cases of C. diphtheriaeendocarditis of an ASD closure device have previously been reported.

Case of Ludwig's angina due to Corynebacterium diphtheriae from western Rajasthan, India-A case report of an uncommon presentation

Corynebacterium diphtheriae is a toxin producing, classically noninvasive bacteria that causes diphtheria a vaccine-preventable disease mainly in children. With increasing vaccine cover, new spectrum of infections is increasingly seen involving invasive infections and nontoxigenic strains of C. diphtheriae. Here, we present a case of Ludwig's angina caused by C. diphtheriae in a 45-year-old female. Only Corynebacterium spp. have been previously reported in Ludwig's angina patients.

Corynebacterium diphtheriae Native Aortic Valve Endocarditis in a Patient With Prosthetic Mitral Valve: A Rare Presentation

Infective endocarditis due to non-toxigenic Corynebacterium diphtheriae is uncommon. We describe the case of a 42-year-old male with a history of mitral valve replacement with prosthetic valve for 4 years. He presented with fever, weight loss, dyspnea on exertion and orthopnea. The echocardiography demonstrated large vegetation attached on the left coronary cusp of the aortic valve with moderately severe aortic regurgitation but sparing of the prosthetic mitral valve. Three separate blood cultures grew Corynebacterium species. The patient underwent aortic valve replacement due to valvular dysfunction and congestive heart failure. C. diphtheriae DNA was detected by 16 S rDNA polymerase chain reaction (PCR) from the heart valve tissue. The patient recovered completely with combine antibiotics and surgical intervention. He was discharged from the hospital with good clinical outcome.

Pathogenic properties of a Corynebacterium diphtheriae strain isolated from a case of osteomyelitis

Corynebacterium diphtheriae is typically recognized as a colonizer of the upper respiratory tract (respiratory diphtheria) and the skin (cutaneous diphtheria). However, different strains of Corynebacteriumdiphtheriae can also cause invasive infections. In this study, the characterization of a non-toxigenic Corynebacteriumdiphtheriae strain (designated BR-INCA5015) isolated from osteomyelitis in the frontal bone of a patient with adenoid cystic carcinoma was performed. Pathogenic properties of the strain BR-INCA5015 were tested in a Caenorhabditis elegans survival assay showing strong colonization and killing by this strain. Survival rates of 3.8±2.7 %, 33.6±7.3 % and 0 % were observed for strains ATCC 27010T, ATCC 27012 and BR-INCA5015, respectively, at day 7. BR-INCA5015 was able to colonize epithelial cells, showing elevated capacity to adhere to and survive within HeLa cells compared to other Corynebacteriumdiphtheriae isolates. Intracellular survival in macrophages (THP-1 and RAW 264.7) was significantly higher compared to control strains ATCC 27010T (non-toxigenic) and ATCC 27012 (toxigenic). Furthermore, the ability of BR-INCA5015 to induce osteomyelitis was confirmed by in vivo assay using Swiss Webster mice.

Corynebacterium endocarditis of a percutaneously placed transcatheter pulmonary valve

We report a case of endocarditis of a transcatheter pulmonary valve-in-valve in a 14-year-old boy with tetralogy of Fallot. He presented with recurrent low-grade fevers, lethargy, and anorexia. Multiple blood cultures grew a gram-positive rod, Corynebacterium pseudodiphtheriticum. He was taken to the operating room for removal of the vegetative endocarditis and pulmonary valve replacement.

Non-Toxigenic Penicillin and Cephalosporin-Resistant Corynebacterium diphtheriae Endocarditis in a Child: A Case Report and Review of the Literature

Reports of invasive disease caused by non-toxigenic Corynebacterium diphtheriae are increasing; however, medical management has not been extensively studied. We describe what we believe is the first documented case of penicillin and cephalosporin-resistant C diphtheriae endocarditis in a child successfully treated with vancomycin, meropenem, and valvular replacement surgery.

Nontoxigenic highly pathogenic clone of Corynebacterium diphtheriae, Poland, 2004-2012

Twenty-five cases of nontoxigenic Corynebacterium diphtheriae infection were recorded in Poland during 2004–2012, of which 18 were invasive. Alcoholism, homelessness, hepatic cirrhosis, and dental caries were predisposing factors for infection. However, for 17% of cases, no concomitant diseases or predisposing factors were found.

Infective endocarditis in New Zealand children 1994-2012

BACKGROUND

New Zealand is a developed country with high incidence of bacterial infections and postinfectious sequelae including rheumatic heart disease. We sought to describe the clinical and microbiology features of children with infective endocarditis (IE) between 1994 and 2012.

METHODS

Retrospective review of patients <16 years identified from hospital records.

RESULTS

In total 85 episodes occurred in 82 children and 68 (80%) were classified as Definite IE and 17 as Possible IE according to modified Duke criteria. From Pacific Island countries, 13 cases were referred. There were 72 children who originated in New Zealand, of whom 52% were either indigenous New Zealand Maori or Pacific migrants. The median age at diagnosis was 7 (0-15) years. Of the 85 cases, 51 (60%) had congenital heart disease 10 children with rheumatic heart disease developed IE. Of the 85 cases, 35 (41%) met our criteria for healthcare-associated IE. 39/85 underwent surgery for IE. As direct result of IE, 4 (4.7%) children died and 9% of survivors had neurologic sequelae. Attributable in-hospital mortality was 4.7%. Staphylococcus aureus was the most common organism, accounting for 26 episodes (30.6%). Other notable pathogens included Corynebacterium diphtheriae (10 cases, 11.8%) and Streptococcus pyogenes (7 cases, 8.2%). In 6 episodes, the microbiologic diagnosis was made by 16S ribosomal RNA testing of excised cardiac tissue.

CONCLUSIONS

Congenital heart disease was the major risk factor for IE; however, rheumatic heart disease is also an important risk factor in New Zealand, with implications for local endocarditis prophylaxis recommendations. In addition to a high burden of healthcare-associated and staphylococcal IE, pathogens such as C. diphtheriae and S. pyogenes occurred. 16S ribosomal RNA testing is a useful tool to determine the etiologic agent in culture-negative IE.

SubMICs of penicillin and erythromycin enhance biofilm formation and hydrophobicity of Corynebacterium diphtheriae strains

Subinhibitory concentrations (subMICs) of antibiotics may alter bacterial surface properties and change microbial physiology. This study aimed to investigate the effect of a subMIC (&frac18; MIC) of penicillin (PEN) and erythromycin (ERY) on bacterial morphology, haemagglutinating activity, cell-surface hydrophobicity (CSH) and biofilm formation on glass and polystyrene surfaces, as well as the distribution of cell-surface acidic anionic residues of Corynebacterium diphtheriae strains (HC01 tox(-) strain; CDC-E8392 and 241 tox(+) strains). All micro-organisms tested were susceptible to PEN and ERY. Growth in the presence of PEN induced bacterial filamentation, whereas subMIC of ERY caused cell-size reduction of strains 241 and CDC-E8392. Adherence to human erythrocytes was reduced after growth in the presence of ERY, while CSH was increased by a subMIC of both antibiotics in bacterial adherence to n-hexadecane assays. Conversely, antibiotic inhibition of biofilm formation was not observed. All strains enhanced biofilm formation on glass after treatment with ERY, while only strain 241 increased glass adherence after cultivation in the presence of PEN. Biofilm production on polystyrene surfaces was improved by &frac18; MIC of ERY. After growth in the presence of both antimicrobial agents, strains 241 and CDC-E8392 exhibited anionic surface charges with focal distribution. In conclusion, subMICs of PEN and ERY modified bacterial surface properties and enhanced not only biofilm formation but also cell-surface hydrophobicity. Antibiotic-induced biofilm formation may contribute to the inconsistent success of antimicrobial therapy for C. diphtheriae infections.

Diphtheria - 'The strangling angel' of children

Diphtheria, an acute infectious condition caused by Corynebacterium diphtheriae, was once a major killer of children. Although the mortality rates dropped dramatically in the mid-twentieth century, due to a combination of improved standards of living and immunization programs, outbreaks are still occurring. Two children, aged four and five years respectively, are reported to demonstrate characteristic features of lethal cases. Death in case 1 was due to an extensive upper airway pseudomembrane causing acute respiratory failure. The diagnosis of diphtheria was only made at postmortem. Death in case 2 was due to acute cardiac failure with heart block complicating diphtheria. Other mechanisms in fatal cases involve disseminated intravascular coagulation, renal and endocrine failure. Declining levels of immunity among adults has resulted in a change in the epidemiological pattern of the disease with an older age of victims in recent outbreaks. As a result of population shifts and failure to immunize children it is likely that forensic pathologists may see more cases of diphtheria in the future. Due to the rarity of cases in Western communities and atypical presentations, the diagnosis may only be established at autopsy.

Bloodstream infection caused by nontoxigenic Corynebacterium diphtheriae in an immunocompromised host in the United States

Corynebacterium species are well-known causes of catheter-related bloodstream infections. Toxigenic strains of Corynebacterium diphtheriae cause respiratory diphtheria. We report a bloodstream infection caused by a nontoxigenic strain of C. diphtheriae and discuss the epidemiology, possible sources of the infection, and the implications of rapid species identification of corynebacteria.