A Case Report of Corynebacterium Tuberculostearicum Infection.

BACKGROUND: The goal was to report a rare case of lymphadenitis caused by Corynebacterium tuberculostearicum, and the laboratory's coping approach in the isolation and identification of this rare pathogen to improve the understanding of the disease. METHODS: Lymph node biopsy was performed in a patient with suspected tuberculous lymphadenitis, and the biopsy tissue was isolated and cultured. RESULTS: The culture was Gram positive Corynebacterium, which was identified as Corynebacterium tuberculostearicum by microbial mass spectrometry and 16S rRNA gene sequencing. Antimicrobial susceptibility test showed that the drug was sensitive to daptomycin, doxycycline, gentamicin, linezolid, vancomycin, and meropenem, but resistant to ciprofloxacin, clindamycin, erythromycin, rifampicin, compound sulfamethoxazole, ceftriaxone, and cefepime. CONCLUSIONS: This is a case of Corynebacterium tuberculostearicum infection. Case reports of Corynebacterium tuberculostearicum infection are relatively rare in China. Through case study, we can provide help for laboratory isolation, identification, clinical diagnosis, and treatment.

Infective endocarditis and septic arthritis caused by Corynebacteriumstriatum.

Corynebacterium striatum occasionally causes nosocomial infections, such as catheter-related bloodstream infection and pneumonia; however, C. striatum-related infective endocarditis or septic arthritis is uncommon. We present the case of an 85-year-old woman with infective endocarditis at the native valve and septic arthritis at the native shoulder joint caused by C. striatum. The patient was admitted for a 10-day history of fever and right shoulder pain. She had no history of artificial device implantation, injury, arthrocentesis, or hospitalization. A physical examination revealed conjunctival petechiae, a systolic heart murmur, and right shoulder joint swelling. C. striatum was observed in two blood culture sets. Transesophageal echocardiography revealed vegetation in the right aortic coronary cusp. Arthrocentesis at the right shoulder aspirated pyogenic fluid and C. striatum was detected in the culture. The patient was diagnosed with infective endocarditis and septic arthritis caused by C. striatum, and ampicillin was administered based on antimicrobial susceptibility test results. The patient's condition was initially stable; however, she developed pulmonary congestion on day 56 and eventually died. An autopsy demonstrated perforation of the aortic left coronary cusp with vegetation. C. striatum may cause native valve endocarditis and native joint septic arthritis.

[Pyogenic spondylitis after Corynebacterium striatum blood stream infection following allogeneic hematopoietic stem cell transplantation for malignant lymphoma].

Patient 1 was a 70-year-old woman with refractory diffuse large B-cell lymphoma who received allogeneic peripheral blood stem cell transplantation from an HLA-haploidentical related donor. Upper back pain appeared on day63, and Th8-Th9 pyogenic spondylitis was diagnosed based on magnetic resonance imaging (MRI). Blood culture on day14 identified Corynebacterium striatum as the causative bacteria of blood stream infection (BSI). The pyogenic spondylitis resolved after treatment with daptomycin for 2 months. Patient 2 was a 65-year-old man with relapsed angioimmunoblastic T-cell lymphoma who received bone marrow transplantation from an HLA-DR single-antigen-mismatched unrelated donor. Lower back pain appeared on day30, and L4-L5 pyogenic spondylitis was diagnosed based on MRI. Blood culture was negative. Daptomycin and clindamycin were selected for treatment based on the drug susceptibility of bacteria that had caused pre-engraftment BSI (Escherichia coli on day3 and Corynebacterium striatum on day9), and the pyogenic spondylitis resolved after 6 months of this treatment. Pyogenic spondylitis should be considered in the differential diagnosis of back pain accompanied by BSI before engraftment in allogeneic hematopoietic stem cell transplant recipients.

A serum NMR metabolomic analysis of the Corynebacterium pseudotuberculosis infection in goats.

Caseous lymphadenitis (CLA), an infectious disease caused by Corynebacterium pseudotuberculosis in small ruminants, is highly prevalent worldwide. Economic losses have already been associated with the disease, and little is known about the host-pathogen relationship associated with the disease. The present study aimed to perform a metabolomic study of the C. pseudotuberculosis infection in goats. Serum samples were collected from a herd of 173 goats. The animals were classified as controls (not infected), asymptomatic (seropositives but without detectable CLA clinical signs), and symptomatic (seropositive animals presenting CLA lesions), according to microbiological isolation and immunodiagnosis. The serum samples were analyzed using nuclear magnetic resonance (1H-NMR), nuclear Overhauser effect spectroscopy (NOESY), and Carr-Purcell-Meiboom-Gill (CPMG) sequences. The NMR data were analyzed using chemometrics, and principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) were performed to discover specific biomarkers responsible for discrimination between the groups. A high dissemination of the infection by C. pseudotuberculosis was observed, being 74.57% asymptomatic and 11.56% symptomatic. In the evaluation of 62 serum samples by NMR, the techniques were satisfactory in the discrimination of the groups, being also complementary and mutually confirming, demonstrating possible biomarkers for the infection by the bacterium. Twenty metabolites of interest were identified by NOESY and 29 by CPMG, such as tryptophan, polyunsaturated fatty acids, formic acid, NAD+, and 3-hydroxybutyrate, opening promising possibilities for the use of these results in new therapeutic, immunodiagnosis, and immunoprophylactic tools, as well as for studies of the immune response against C. pseudotuberculosis. KEY POINTS: • Sixty-two samples from healthy, CLA asymptomatic, and symptomatic goats were screened • Twenty metabolites of interest were identified by NOESY and 29 by CPMG • 1H-NMR NOESY and CPMG were complementary and mutually confirming.

Clinical characteristics and therapeutic strategy of granulomatous mastitis accompanied by Corynebacterium kroppenstedtii: a retrospective cohort study.

BACKGROUND: Increasing evidence has suggested that Corynebacterium kroppenstedtii is associated with some cases of granulomatous mastitis, mostly based on pathology or microbiology. We aimed to identify the clinical characteristics and treatment regimens for granulomatous mastitis with Corynebacterium kroppenstedtii infection. Understanding these clinical features is essential for patient care. METHODS: We retrospectively collected data on 201 patients who were pathologically diagnosed with granulomatous mastitis and had microbiological results of either Corynebacterium kroppenstedtii or no bacterial growth and recorded and analysed their demographics, clinical characteristics, and clinical outcomes. RESULTS: There were 107 patients in the CK group and 94 patients in the negative group. Sinus formation (x2 = 13.028, p = 0.000), time to complete remission at the first treatment period (Z = -3.027, p = 0.002), diameter of breast mass at first-time medical consultancy (Z = -2.539, p = 0.011) and recurrence (x2 = 4.953, p = 0.026) were statistically significant. Age (Z = -1.046, p = 0.295), laterality (x2 = 4.217, p = 0.121), time to presentation since the last delivery (x2 = 0.028, p = 0.868), BMI (Z = -0.947, p = 0.344), lactation time (Z = -1.378, p = 0.168), parity (x2 = 1.799, p = 0.180), gravida (Z = -0.144, p = 0.885), history of lactational mastitis or abscess (x2 = 0.115, p = 0.734), local trauma (x2 = 0.982, p = 0.322), hyperprolactinemia (x2 = 0.706, p = 0.401), erythema nodosum (x2 = 0.292, p = 0.589), and nipple discharge (x2 = 0.281, p = 0.596) did not demonstrate statistical significance. Regarding recurrence related to therapeutic strategy, except for surgery combined with immunosuppressants (x2 = 9.110, p = 0.003), which was statistically significant, none of the other treatment regimens reached statistical significance. The recurrence rate of patients in the CK group using rifampicin in their treatment course was 22.0% (x2 = 4.892, p = 0.027). CONCLUSIONS: Granulomatous mastitis accompanied by Corynebacterium kroppenstedtii more easily forms sinuses and has a higher recurrence rate. Both of the clinical characteristics may indicate that Corynebacterium kroppenstedtii plays an important role in the development and progression of granulomatous mastitis. Lipophilic antibiotics may be essential for granulomatous mastitis with Corynebacterium kroppenstedtii infection.

Pitted keratolysis.

Pitted keratolysis (PK) is a common superficial bacterial skin infection confined to the stratum corneum. It is clinically characterized by multifocal, discrete, pits or crater-like punched-out lesions, commonly over the pressure-bearing aspects of the foot. It is asymptomatic and associated with malodour. The surface is often moist and macerated. The diagnosis of PK is often clinical and diagnostic procedures are usually unnecessary. Lifestyle modifications form the cornerstone of the management of PK. It responds well to topical antimicrobials.

Sisal wool skin disease in Merino sheep in the Argentine Patagonia region: Identification and molecular diagnosis of Corynebacterium bovis from skin lesions.

BACKGROUND: Sisal wool condition is a skin disease affecting Merino sheep in the Argentine Patagonia region. Corynebacterium spp. isolates have previously been isolated from skin swabs from lesions, while specific identification of the bacteria involved has not been reported. HYPOTHESIS/OBJECTIVES: The aim of this work was to characterize the bacterial agent isolated from sisal wool lesions and to develop a diagnostic method for field surveillance. MATERIALS AND METHODS: Molecular identification of a collection of 72 isolates obtained previously was performed using PCR and 16S rRNA and rpoB sequencing. A field survey was carried out on two farms in the Río Negro province of Argentine Patagonia. Swab samples from sheep with and without skin lesions were collected and analysed by PCR and culture. RESULTS: Isolates analysed were confirmed by sequencing as Corynebacterium bovis. Using a PCR test without culture step, all field samples from affected sheep were positive for C. bovis; samples from the healthy skin from the same animals or clinically healthy sheep all were negative. CONCLUSIONS AND CLINICAL RELEVANCE: Sisal wool skin disease was associated with C. bovis infection based on culture and PCR methods; the latter may be useful for helping to pursue a disease control strategy.

Clinical features and recurrence of Corynebacterium kroppenstedtii infection in patients with mastitis.

BACKGROUND: Few studies have investigated the differences in clinical features of patients with mastitis following Corynebacterium kroppenstedtii infection, and most focused on the bacterial antimicrobial susceptibility, detection methods and therapy. METHODOLOGY: There were 133 patients with mastitis infected by C. kroppenstedtii between August 2016 and September 2019. C. kroppenstedtii was identified using mass spectrometry. The demographics, clinical diagnosis, laboratory test results of different types of mastitis combined with bacillus infection, and the effects of different treatments in reducing recurrence were compared. RESULTS: The incidence of pus following C. kroppenstedtii infection was higher in patients with non-granulomatous lobular mastitis (NGLM; 56.6%) than in those with granulomatous lobular mastitis (GLM; 33.3%; χ2 = 7.072, p = 0.008). While C-reactive protein (CRP) was higher in the GLM group (12.50 mg/L) than in the NGLM group (6.05 mg/L; Z = - 2.187, p = 0.029). Treatment with local lavage (triamcinolone acetonide) and antibiotics (cefuroxime) showed a recurrent rate of 25.9% in C. kroppenstedtii infection. CONCLUSION: Increased pus, large masses, and an elevated CRP level may occur in patients with mastitis infected by C.kroppenstedtii. These clinical features may guide the determination of the bacterial infection in patients with mastitis. Combining an antibiotic with a triamcinolone acetonide lavage, preferably cefuroxime, may reduce the recurrence.

Assessment of rSodC, rPknG, rNanH, and rSpaC as Antigens for Diagnostic Tools Against Caseous Lymphadenitis.

Corynebacterium pseudotuberculosis is a bacillus that causes caseous lymphadenitis in small ruminants, leading to great losses to rural producers; thus, an efficient diagnosis is necessary for using disease control measures. This study aimed to evaluate the antigenic potential of four C. pseudotuberculosis recombinant proteins (rSodC, rPknG, rNanH, and rSpaC) against sera of goat and sheep experimentally infected with one of three different C. pseudotuberculosis strains. Goats were infected with CAP76 or CAP21 strain (n = 10), sheep with VD57 strain (n = 6), and a group of not-infected animals (goats and sheep) were kept as a healthy control (healthy n = 12). Sera were collected at 0, 14, 60, 90, 180, or 190 days after inoculation for antigenicity testing using Western blotting and enzyme-linked immunosorbent assay (ELISA) techniques. Cross-reactivity tests with recombinant proteins were performed in goat serum experimentally vaccinated with Nocardia sp. or Rhodococcus equi bacterin. The rSodC protein showed discriminatory antigenic reactivity with a statistically significant difference against three different C. pseudotuberculosis strains evaluated in goats and sheep samples, while rPknG showed statistical significance only against two C. pseudotuberculosis strains evaluated in goats. rSodC was proved to be a strong candidate as a tool for diagnosis of C. pseudotuberculosis infection, once it was able to recognize antibodies against all strains evaluated in goats and sheep.

Complicated urinary tract infection caused by Corynebacterium urealyticum - A pathogen that should not be forgotten.

Although Corynebacterium urealyticum has rarely been isolated in diagnostic laboratories, this bacterium can be a significant uropathogen causing significant complications. It causes cystitis and alkaline encrusted cystitis, commonly involved in patients who need prolonged hospitalization and bladder catheterisation. We report here a case of a 19-yearold young man who was diagnosed with N-Methyl Daspartate receptor (NMDAR) encephalitis that requires hospitalization for optimization of rehabilitation treatment in Hospital Kuala Lumpur, Malaysia. His urine culture isolated slow growing gram-positive pleomorphic rods subsequently identified as C. urealyticum. Based on the risk factors, the isolation of C. urealyticum could not be simply dismissed as contaminants. The patient was treated successfully with vancomycin for two weeks.

Widespread Disease in Hedgehogs (Erinaceus europaeus) Caused by Toxigenic Corynebacterium ulcerans.

Toxin-producing Corynebacterium ulcerans, a causative agent of diphtheria in humans, was isolated from 53 hedgehogs in Belgium during the spring of 2020. Isolates showed low levels of acquired antimicrobial drug resistance. Strain diversity suggests emergence from an endemic situation. These findings stress the need for raising public awareness and improved wildlife disease surveillance.

Direct detection of Corynebacterium striatum, Corynebacterium propinquum, and Corynebacterium simulans in sputum samples by high-resolution melt curve analysis.

BACKGROUND: Pulmonary infections caused by non-diphtheriae corynebacteria are increasing. However, rapid identification of Corynebacterium species poses a challenge due to the low genetic variation within the genus. METHODS: Three reference strains and 99 clinical isolates were used in this study. A qPCR followed by high-resolution melting (HRM) targeting ssrA was performed to simultaneously identify C. striatum, C. propinquum and C. simulans. To further evaluate this assay's performance, 88 clinical sputum samples were tested by HRM and the detection results were compared with those of the traditional culture method and multiple cross-displacement amplification (MCDA) assay. RESULTS: The melting curve produced by a pair of universal primers generated species-specific HRM curve profiles and could distinguish the three target species from other related bacteria. The limit of detection of HRM assay for DNA from the three purified Corynebacterium species was 100 fg. Compared with the culture method, HRM detected 22 additional positive specimens, representing a 23.9% relative increase in detection rate. The HRM assay had 98.4% (95% confidence interval [CI], 90.5-99.9%) sensitivity and 100% (95% CI, 82.8-100%) specificity. Additionally, 95.5% concordance between HRM and MCDA (κ = 0.89 [95% CI, 0.79-0.99]) was noted. CONCLUSIONS: The HRM assay was a simple, rapid, sensitive, and specific diagnostic tool for detecting C. striatum, C. propinquum, and C. simulans, with the potential to contribute to early diagnosis, epidemiological surveillance, and rapid response to outbreak.

Corynebacterium striatum: An emerging nosocomial skin and soft-tissue pathogen.

The genus Corynebacterium is composed of Gram-positive, aerobic, non-motile, non-spore-forming bacilli that are widely distributed throughout the environment. They are usually found as commensals on the skin and are often considered as mere contaminants when isolated from clinical samples. We describe a patient with skin and soft-tissue infections due to Corynebacterium striatum following exploratory laparotomy identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The clinical importance and pathogenic potential of Corynebacterium species, especially C. striatum, cannot be underestimated. This report is a reminder to physicians of the possible pathogenicity of non-diphtherial Corynebacteria.

Corynebacterium sp. isolated from blood culture of a bacteremic patient. Will the assumptions about a new corynebacterium be confirmed?

A case report is presented of a patient with suspected septicaemia from whose blood culture a new strain of Corynebacterium sp. was isolated. Until now, no report of this strain isolated from human clinical materials has been available in the literature. In addition to a brief clinical description of the case, the article also features morphological, biochemical properties as well as antibiogram of the bacterium. It describes also methods used for the identification of this isolate. The aim of the work was to highlight a novel and rare coryneform strain.

[Corynebacterium pyruviciproducens and Corynebacterium amycolatum mastitis in immunocompetent no breastfeeding women]. / Mastitis por Corynebacterium pyruviciproducens y Corynebacterium amycolatum en mujeres inmunocompetentes no lactantes.

Corynebacterium species, other than Corynebacterium diphteriae, are usually dismissed as contaminants when recovered from patient's samples. It is often difficult to decide whether these bacteria have clinical relevance or not. The Corynebacterium genus has been implicated in a wide variety of human infections. In this brief report, two cases of mastitis caused by Corynebacterium pyruviciproducens and Corynebacterium amycolatum are described in not breastfeeding women. These patients were immunocompetent with no evidence of ongoing risk factors for mastitis. This report seeks to give importance to this genus by always ranking cultures, starting with a thorough sample collection up until a complete evaluation of lab results and clinical presentation.

[Corynebacterium kroppenstedtii breast infections: Report of four cases]. / Infecciones mamarias por Corynebacterium kroppenstedtii: comunicación de 4 casos.

Corynebacterium kroppenstedtii is an immobile, non-sporulated, glucose-fermenting and lipophilic gram-positive rod of the skin microbiota. In recent years, numerous isolates of this species have been reported mainly in breast infections, such as abscesses and granulomatous mastitis. We present here four cases of C. kroppenstedtii infections isolated from breast aspiration samples in women. C. kroppenstedtii was identified by conventional methodology and mass spectrometry (MALDI-TOF MS). Using the epsilometric method, these isolates showed susceptibility to penicillin, ceftriaxone, minocycline, ciprofloxacin, and vancomycin, and variable susceptibility to clindamycin and trimethoprim sulfamethoxazole. Due to the association of C. kroppenstedtii with mammary infections, the identification at the species level of those corynebacteria isolated from this location is highly advisable in order to reach the final diagnosis and to test the antimicrobial susceptibility in order to apply the appropriate antibiotic treatment.

Corynebacterium spp. - problematic pathogens of the human respiratory tract (review of literature).

Corynebacterium spp. - representatives of the normal microflora of the human body, but their role in the development of diseases in both immunocompromised and immunocompetent patients is known. Corynebacterim spp. (C. pseudodiphtheriticum, C. striatum, C. amycolatum, C. accolens, C. argentoratense, etc.) is associated with diseases of the respiratory tract: tracheitis, pharyngitis, rhinosinusitis, bronchitis, etc. They can be transmitted by airborne droplets, household contact, and possibly by hematogenic pathways. Corynebacterim spp. toxins do not produce, but are capable of adhesion and invasion, biofilm formation, production of neuraminidase, hyaluronidase, and hemolysin. It is necessary to take into account not so much the species, but the strain affiliation of isolates of Corynebacterium spp., since among the representatives of one species of non-diphtheria corynebacteria (for example, C. pseudodiphtheriticum), colonizing the respiratory tract, there may be strains that can exhibit not only pathogenic properties, but also probiotic activity. Microbiological diagnostics is based on their quantitative determination in biological material, phenotypic (culture study, test systems for biochemical identification, Vitek 2 automated systems) and genotypic (16SpRNA gene sequencing and rpoB) methods. It is possible to use mass spectrometric analysis (MALDI-ToF-MS). The greatest activity against Corynebacterium spp. in vitro studies preserve vancomycin, teicoplanin, and linezolid. Successful therapy with at least two of the following antimicrobial agents (AMP) has been reported: vancomycin, rifampicin, linezolid, and daptomycin. The sensitivity of isolates of Corynebacterium spp. to AMP is not related to the species, but is due to strain differences, and therefore it is necessary to test each isolated strain. Continuous monitoring of the sensitivity of Corynebacterium spp. strains to AMP is necessary due to the observed variability of these traits. Of particular importance is the identification of multidrug-resistant isolates that are currently considered highly pathogenic. When compiling the review, the databases Scopus, Web of Science, The Cochrane Library, CyberLeninka, RSCI were used.

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.

Post-intravitreal injection endophthalmitis secondary to Turicella otitidis: a case report.

BACKGROUND: Endophthalmitis is a rare but potentially devastating complication of intravitreal injection. The causative organism plays an important role in prognosis following endophthalmitis. Here we present the first reported case of Turicella otitidis endophthalmitis, which is notable for a delayed presentation. CASE PRESENTATION: A 71 year old male who was receiving intravitreal aflibercept injections for neovascular age-related macular degeneration presented 4 weeks after his most recent intravitreal injection and was found to have endophthalmitis. Polymerase chain reaction (PCR) testing of aqueous fluid was positive for Turicella otitidis. The endophthalmitis responded well to treatment with intravitreal antibiotics. CONCLUSIONS: Coryneform bacteria are a rare cause of endophthalmitis, and this is the first reported case of endophthalmitis caused by the corynebacterium species Turicella otitidis. As in this case, post-intravitreal injection endophthalmitis may have a bacterial etiology even with delayed presentation. The relatively indolent disease course and excellent response to intravitreal antibiotics is consistent with previous ophthalmic reports regarding other corynebacteria, as well as with otolaryngology and hematology oncology reports addressing Turicella otitidis specifically. This case supports the growing body of evidence for pathogenicity of Turicella otitidis and demonstrates the utility of PCR for diagnosis in small volume aqueous specimens.

The changing epidemiology of diphtheria in the United Kingdom, 2009 to 2017.

BackgroundDiphtheria is a potentially fatal disease caused by toxigenic strains of Corynebacterium diphtheriae, C. ulcerans or C. pseudotuberculosis.AimOur objective was to review the epidemiology of diphtheria in the United Kingdom (UK) and the impact of recent changes in public health management and surveillance.MethodsPutative human toxigenic diphtheria isolates in the UK are sent for species confirmation and toxigenicity testing to the National Reference Laboratory. Clinical, epidemiological and microbiological information for toxigenic cases between 2009 and 2017 are described in this population-based prospective surveillance study.ResultsThere were 33 toxigenic cases of diphtheria aged 4 to 82 years. Causative species were C. diphtheriae (n = 18) and C. ulcerans (n = 15). Most C. diphtheriae cases were cutaneous (14/18) while more than half of C. ulcerans cases had respiratory presentations (8/15). Two thirds (23/33) of cases were inadequately immunised. Two cases with C. ulcerans infections died, both inadequately immunised. The major risk factor for C. diphtheriae aquisition was travel to an endemic area and for C. ulcerans, contact with a companion animal. Most confirmed C. diphtheriae or C. ulcerans isolates (441/507; 87%) submitted for toxigenicity testing were non-toxigenic, however, toxin positivity rates were higher (15/23) for C. ulcerans than C. diphtheriae (18/469). Ten non-toxigenic toxin gene-bearing (NTTB) C. diphtheriae were also detected.ConclusionDiphtheria is a rare disease in the UK. In the last decade, milder cutaneous C. diphtheriae cases have become more frequent. Incomplete vaccination status was strongly associated with the risk of hospitalisation and death.