Reidentification and determination of drug susceptibility of Corynebacterium diphtheriae and Corynebacterium ulcerans strains isolated from clinical samples in 2023 in Poland. / Reidentyfikacja oraz okreslenie lekowrazliwosci szczepów Corynebacterium diphtheriae i Corynebacterium ulcerans wyizolowanych z próbek materialu klinicznego w 2023 roku w Polsce.

BACKGROUND: Despite the fact that the last cases of fully-symptomatic diphtheria were recorded in Poland in 1996 and 2000, infections caused by non-toxin-producing strains of Corynebacterium still occur. According to the epidemiological reports from ECDC in the second half of 2022, there was an increase in the number of diphtheria cases in European Union countries. As a result, the current issue becomes the appropriate preparation of microbiological laboratories for the diagnosis of Corynebacterium microorganisms. OBJECTIVE: Reidentification of diphtheria bacilli isolated from clinical samples and to assess the drug susceptibility of C. diphtheriae strains isolated in Poland. MATERIAL AND METHODS: The subject of the research were 18 strains isolated from clinical samples in Poland in 2023. Microbiological and genetic methods were used for the reidentification of the strains. Drug susceptibility was assessed using the disk diffusion method, following the new EUCAST recommendations effective from 2023. RESULTS: It was confirmed that all examined strains belonged to the genus Corynebacterium. It was de-monstrated that C. diphtheriae strains proved to be susceptible to increased exposure to benzylpenicillin and cefotaxime. Results obtained using ciprofloxacin allowed categorizing the strains into the intermediate susceptibility category WZE, except for one strain which was resistant to this antibiotic. All tested bacterial strains were susceptible to erythromycin. The C. ulcerans strain exhibited a similar antibiotic resistance profile to penicillin, cefotaxime, and ciprofloxa-cin, with additional detection of resistance to clindamycin. The toxigenicity of the tested strains was excluded. CONCLUSIONS: Based on epidemiological data regarding the emergence of new cases of infections caused by Corynebacterium strains, it is advisable to prepare theoretically and practically laboratories for diagnostics to detect potentially toxigenic diphtheria bacilli. Effective methods for the microbiological diagnosis of diphtheria bacilli are available. It is recommended to monitor the susceptibility to antimicrobial agents in all C. diphtheriae isolates.

Herd-level true seroprevalence of caseous lymphadenitis and paratuberculosis in the goat population of Poland.

A large-scale study was carried out in the Polish goat population in 2014-2021 to determine the herd-level true seroprevalence (HTP) of caseous lymphadenitis (CLA) caused by Corynebacterium pseudotuberculosis (Cp) and paratuberculosis (PTB) caused by Mycobacterium avium ssp. paratuberculosis (Map). Two-stage cluster sampling was applied to herds counting at least 20 adult goats (aged >1 year) and in each herd all males and 10-13 females were tested. At least one seropositive goat regardless of its sex was necessary to consider the herd as infected. HTP was estimated using the Bayesian approach with the Gibbs sampler in the EpiTools and reported as the median and 95 % credibility interval (95 % CrI). A total of 1282 adult goats from 86 herds were serologically tested using two commercial ELISAs (Cp-ELISA and Map-ELISA). At least 1 seropositive result of Cp-ELISA and Map-ELISA was obtained in 73/86 herds (84.9 %) and 40/86 herds (46.5 %), respectively. HTP of CLA was estimated at 73.3 % (95 % CrI: 65.0 %, 80.4 %) and HTP of PTB was estimated at 42.9 % (95 % CrI: 25.8 %, 58.0 %). There was a significant positive association between the occurrence of CLA and PTB in the herds (odds ratio 6.0, 95 % confidence interval: 1.2, 28.8; p = 0.010). Probability of the seropositive result for PTB was also significantly higher in Cp-seropositive goats than in Cp-seronegative goats (odds ratio 3.9, 95 % confidence interval: 2.4, 6.3; p < 0.001) which could indicate either a higher risk of co-infection or a higher rate of false positive results for PTB in Cp-positive goats. To investigate this issue, optical densities obtained in Map-ELISA were compared between Cp-positive and Cp-negative goats and results of Map-ELISA were adjusted accordingly. Map-negative sera from Cp-positive goats turned out to have significantly higher optical densities than Map-negative sera from Cp-negative goats (p < 0.001). After the adjustment, the herd-level apparent seroprevalence of PTB was 41.9 % (36/86 herds) so it still fell within the 95 % CrI of HTP of PTB calculated before the adjustment. Concluding, CLA appears to be widespread in the Polish goat population. In many of them it may be subclinical at the moment, however will likely emerge in the future as the disease follows cyclic pattern in Poland. On the other hand, given the total lack of clinical PTB in Polish goats, an explanation for a high HTP of PTB remains unclear and warrants further studies using tests of higher analytical specificity than ELISA.

Retrospective Study of Infections with Corynebacterium diphtheriae Species Complex, French Guiana, 2016-2021.

Human infections with Corynebacterium diphtheriae species complex (CdSC) bacteria were rare in French Guiana until 2016, when the number of cases diagnosed increased. We conducted an epidemiologic, multicenter, retrospective study of all human CdSC infections diagnosed in French Guiana during January 1, 2016-December 31, 2021. A total of 64 infectious episodes were observed in 60 patients; 61 infections were caused by C. diphtheriae and 3 by C. ulcerans. Estimated incidence increased from 0.7 cases/100,000 population in 2016 to 7.7 cases/100,000 population in 2021. The mean patient age was 30.4 (+23.7) years, and male-to-female ratio was 1.7:1 (38/22). Of the 61 C. diphtheriae isolates, 5 tested positive for the diphtheria toxin gene, and all results were negative by Elek test; 95% (61/64) of cases were cutaneous, including the C. ulcerans cases. The increase in reported human infections underscores the need to raise awareness among frontline healthcare practitioners to improve prevention.

Phylogenomic analyses of multidrug resistant Corynebacterium striatum strains isolated from patients in a tertiary care hospital in the UK.

Corynebacterium striatum is an emerging nosocomial pathogen. This is the first report showing the presence of three distinct multidrug resistant lineages of C. striatum among patients in a UK hospital. The presence of ErmX, Tet(W), Bla and AmpC proteins, and mutations in gyrA gene are associated with the resistance to clindamycin, doxycycline, penicillin and moxifloxacin, respectively. These strains are equipped with several corynebacterial virulence genes including two SpaDEF-type and a novel pilus gene cluster, which needs further molecular characterisation. This study highlights a need of developing an active surveillance strategy for routine monitoring and preventing potential cross-transmission among susceptible patients.

Diptheroids can cause nosocomial UTI and be multidrug resistant: A case report of Corynebacterium striatum, first from India.

Gram positive bacilli in the urine are usually dismissed as contaminants in urine specimens as these are commensal flora of skin and mucous membranes. Corynebacterium species were misidentified in the past due to complex biochemicals but the advent of modern diagnostics has made their identification quicker and accurate. Corynebacterium species have recently emerged as pathogens of nosocomial outbreak potential. C. striatum has been identified as opportunistic nosocomial pathogen causing various infections. We report first case of C. striatum as nosocomial urinary tract infection (UTI) pathogen in a child with bilateral renal disease. C. striatum causing UTI is very rarely reported.

Several confirmed and probable zoonotic cases of toxigenic Corynebacterium ulcerans, Queensland, Australia.

Background: Toxigenic Corynebacterium ulcerans is an emerging zoonosis globally, causing both cutaneous and respiratory diphtheria-like illness. In Queensland, human infection with toxigenic C. ulcerans is rare, with only three cases reported before October 2015. This case series describes five subsequent cases of toxigenic C. ulcerans in Queensland with links to companion animals. Methods: All data were collected as part of routine public health response, and strains were whole genome sequenced for further characterisation. Household contacts were screened, treated with appropriate antibiotics, and received a diphtheria toxoid-containing vaccine if more than five years had elapsed since their last dose. Findings: No epidemiological or genomic links could be established between any of the five patients, including between the two cases notified from the same locality within eight days of each other. The C. ulcerans strains from Cases Two, Four and Five were closely related to the strains isolated from their respective pets by whole genome sequencing. Domestic dogs were identified as the most likely mode of transmission for Cases One and Three; however, this was unable to be laboratory confirmed, since Case One's dog was treated with antibiotics before it could be tested, and Case Three's dog was euthanised and cremated prior to case notification. Interpretation: These are the first reported Australian cases of this emerging zoonosis with links to companion animals. These cases demonstrate the likely transmission route between companion animals and humans, with no evidence of human-to-human transmission. The existing requirement in the Queensland Health Public Health Management Guidelines, of restrictions on cases and some contacts while awaiting swab results, is currently under review.

Phylogenetic analyses of antimicrobial resistant Corynebacterium striatum strains isolated from a nosocomial outbreak in a tertiary hospital in China.

Corynebacterium striatum is an emerging, multidrug-resistant pathogen that frequently causes nosocomial infections worldwide. This study aimed to investigate phylogenetic relationship and presence of genes responsible for antimicrobial resistance among C. striatum strains associated with an outbreak at the Shanxi Bethune Hospital, China, in 2021. Fecal samples were collected from 65 patients with C. striatum infection at Shanxi Bethune Hospital between February 12, 2021 and April 12, 2021. C. striatum isolates were identified by 16S rRNA and rpoB gene sequencing. E-test strips were used to examine the antimicrobial susceptibility of the isolates. Whole-genome sequencing and bioinformatics analysis were employed to assess the genomic features and identify antimicrobial resistance genes of the isolates. Crystal violet staining was conducted to determine the ability of biofilm formation of each isolate. A total of 64 C. striatum isolates were identified and categorized into 4 clades based on single nucleotide polymorphisms. All isolates were resistant to penicillin, meropenem, ceftriaxone, and ciprofloxacin but susceptible to vancomycin and linezolid. Most isolates were also resistant to tetracycline, clindamycin, and erythromycin, with susceptibility rates of 10.77, 4.62, and 7.69%, respectively. Genomic analysis revealed 14 antimicrobial resistance genes in the isolates, including tetW, ermX, and sul1. Crystal violet staining showed that all isolates formed biofilms on the abiotic surface. Four clades of multidrug-resistant C. striatum spread in our hospitals possibly due to the acquisition of antimicrobial resistance genes.

Case Report: Bloodstream Infection with Toxigenic Corynebacterium diphtheriae and Gram-Negative Sepsis in a Child with Burns.

Corynebacterium (C.) diphtheriae is the agent for a contagious infection, diphtheria. It may manifest as pharyngitis with pseudomembrane formation and cervical lymphadenopathy, cutaneous infection, or as an asymptomatic carrier. Corynebacterium (C.) diphtheriae is not an invasive organism and it remains in the superficial layers of skin lesions and respiratory mucosa. Systemic complications, such as bacteremia, are rare. We report a case of toxigenic C. diphtheriae detected from blood culture of a 1-year-old male patient with burns, who succumbed to the infection after 8 days of stay in the hospital. Patient did not have specific clinical features suggestive of diphtheria. Initial identification of C. diphtheriae was done based on culture, Albert stain findings, biochemical tests and subsequently toxigenicity testing was done by polymerase chain reaction. Although diphtheria vaccination in infancy is universally recommended since the creation of the Expanded Program on Immunization in the 1970s, there have been reports of toxigenic strains of C. diphtheriae in a considerable number of cases. Rapid and accurate identification of C. diphtheriae infection is crucial to prevent mortality. Continued surveillance for diphtheria is needed to reduce transmission and mortality rates.

Intramammary infections with Corynebacterium spp. in bovine lactating udder quarters.

Corynebacterium spp. are frequently detected in bovine quarter milk samples, yet their impact on udder health has not been determined completely. In this longitudinal study, we collected quarter milk samples from a dairy herd of approximately 200 cows, ten times at 14 d intervals. Bacteriologically, Catalase-positive and Gram-positive rods were detected in 22.7% of the samples. For further species diagnosis, colonies were analyzed by MALDI-TOF MS. Corynebacterium bovis, C. amycolatum, C. xerosis and 10 other Corynebacterium spp. were detected. The three aforementioned species accounted for 88.4%, 8.65% and 0.94% of all cultured Corynebacterium spp., respectively. For further evaluation of infection dynamics, the following three infection definitions were applied: A (2/3 consecutive samples positive for the same species), B (≥1000 cfu/mL in one sample), C (isolated from a clinical mastitis case). Infections according to definition B occurred most frequently and clinical mastitis with Corynebacterium spp. occurred once during sampling. Life tables were used to determine the duration of infection. According to infection definition A, infection durations of 111 d and 98 d were obtained for C. bovis and C. amycolatum, respectively. Exemplarily, longer lasting infections were examined for their strain diversity by RAPD PCR. A low strain diversity was found in the individual quarters that indicates a longer colonization of the udder parenchyma by C. bovis and C. amycolatum.

Epidemiological, bacteriological and molecular studies on caseous lymphadenitis in sheep of Dakhlia, Egypt.

Caseous lymphadenitis (CLA) is a chronic and insidious disease that mainly affects small ruminants and caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis). The aims of this research were to identify C. pseudotuberculosis by PCR from pyogenic lesions, to study the phylogenetic analysis of C. pseudotuberculosis and to detect the prevalence based on the detected superficial lesions of CLA in Dakahlia governorate, Egypt. Out of 3471 clinically examined animals, 129 (3.71%) animals were affected with CLA. The isolation rate of C. pseudotuberculosis in abscess of sheep was 45.74% (59/129). Out of 129 samples examined by PCR assay, 63 (48.83%) were positive phospholipase D (PLD) indicated at fragment size 203 bp. This is the first phylogenetic analysis study of C. pseudotuberculosis isolate in Egypt which was isolated from infected sheep. Nucleotide sequence identity data demonstrated that C. pseudotuberculosis PLD gene (MW187942) Dakahlia share homology 99.01%, 98.83 and 98.48% with Zagazig, Egypt (MN867024), Tamil nadu, India (MG720636) and Sudan (MG692441), respectively. In conclusion, this study provided information on the molecular detection and phylogeny of C. pseudotuberculosis in Egypt. Findings of this study can be conducted in other CLA endemic countries with similar animal breeding practices in the Middle East and developing countries.

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.

Worldwide survey of Corynebacterium striatum increasingly associated with human invasive infections, nosocomial outbreak, and antimicrobial multidrug-resistance, 1976-2020.

Corynebacterium striatum is part of microbiota of skin and nasal mucosa of humans and has been increasingly reported as the etiologic agent of community-acquired and nosocomial diseases. Antimicrobial multidrug-resistant (MDR) C. striatum strains have been increasingly related to various nosocomial diseases and/or outbreaks worldwide, including fatal invasive infections in immunosuppressed and immunocompetent patients. Although cases of infections by C. striatum still neglected in some countries, the improvement of microbiological techniques and studies led to the increase of survival of patients with C. striatum nosocomial infections at different levels of magnitude. Biofilm formation on abiotic surfaces contributes for the persistence of virulent C. striatum and dissemination of antimicrobial resistance in hospital environment. Besides that, empirical antibiotic therapy can select multi-resistant strains and transfer intra and interspecies genes horizontally. In this study, a worldwide survey of C. striatum human infections and nosocomial outbreaks was accomplished by the analysis of clinical-epidemiological and microbiological features of reported cases from varied countries, during a 44-year period (1976-2020).

Corynebacterium freneyi Bacterial Septicemia Secondary to Contagious Ecthyma in a Wild Muskox (Ovibos moschatus).

A wild muskox (Ovibos moschatus) with dermatitis typical of contagious ecthyma had secondary bacterial septicemia with Corynebacterium freneyi that included laminitis, hepatitis, and suppurative encephalitis. This case supports the association between orf virus infection and fatal secondary infections, which may have contributed to population declines on Victoria Island, Canada.

Caseous lymphadenitis outbreak in a small ruminant herd.

BACKGROUND: Caseous lymphadenitis (CLA) is a chronic disease caused by the bacterium Corynebacterium pseudotuberculosis that affects small ruminants worldwide. AIM: The objective of this case report is to describe an outbreak of CLA that occurred at the California State Polytechnic University, Pomona, in the summer of 2019 and the management strategies employed therein to contain the spread. METHODS: After careful physical screening, blood serum samples from the entire herd (n = 218 sheep, n = 32 goats) were tested using the synergistic hemolysis inhibition test to reveal antibodies present. RESULTS: Animals with titer counts above 1:64 and/or containing CLA lesions were isolated and culled (n = 33 sheep,n = 4 goats) within 2 weeks of testing. Female sheep (n = 160) had higher titer counts and were culled at a much higher rate than male sheep (n = 58) (20% vs. 1.72%), whereas male goats (n = 9) more often had high titer counts and were culled as opposed to female goats (n = 23) (33.33% vs. 4.35%). CONCLUSION: Vaccines were administered to the remainder of the herd following culling. Additional management strategies were employed, the outcome of which was a zero recurrence through August 2021.

Corynebacterium Jeikeium Endocarditis: A Review of the Literature.

Corynebacterium jeikeium is a gram-positive, aerobic, pleomorphic, nonspore forming bacillus, commonly present on the skin surface. Infective endocarditis secondary to C. jeikeium most commonly affects left-sided heart valves and has a higher likelihood to require valve replacement compared to other Corynebacterium endocarditis. C. jeikeium endocarditis is extremely difficult to treat as it is characteristically resistant to penicillin, cephalosporins and aminoglycosides, and sensitivity to quinolones, macrolides, tetracyclines and rifampin is variable. Despite treatment, mortality rates as high as 33% have been reported. We hereby review the literature regarding the epidemiology, diagnosis and treatment of this deadly microorganism.

Genomic epidemiology of Corynebacterium striatum from three regions of China: an emerging national nosocomial epidemic.

BACKGROUND: Corynebacteritum straitum has been considered as an emerging multi-drug-resistant (MDR) pathogen. Isolation of MDR C. striatum as the only organism from respiratory samples from hospitalized patients is increasing in China. AIM: To elucidate the genomic epidemiology and evolution of C. striatum in China. METHODS: A total of 260 isolates from 2016 to 2018 were collected from three hospitals in three regions of China. Antibiotic sensitivity testing was performed on all isolates. Whole-genome sequencing was applied to all isolates to assess their genomic diversity and relationships and detect the presence of antimicrobial resistance genes (ARG) and ARG cassettes. FINDINGS: Almost all isolates (96.2%, 250/260) showed multi-drug-resistance. Genome sequencing revealed four major lineages with lineage IV emerging as the epidemic lineage. Most of the diversity was developed in the last 6 years. Each hospital has its own predominant clones with potential spread between Hebei and Guangdong hospitals. Genomic analysis further revealed multiple antimicrobial resistance genes. CONCLUSIONS: Our results suggested that four lineages of C. striatum have spread in parallel across China, causing persistent and extensive transmissions within hospitals. MDR C. striatum infection has become a national epidemic. Antibiotic-driven selection pressure may have played significant roles in forming persistent and predominant clones. Our data provide the basis for surveillance and prevention strategies to control the epidemic caused by MDR C. striatum.

Toxigenic Corynebacterium ulcerans associated with upper respiratory infections in cats and dogs.

OBJECTIVES: To describe infection in companion animals with the zoonotic pathogen Corynebacterium ulcerans and to determine its prevalence in clinically-affected and healthy animals. MATERIALS AND METHODS: The clinical presentation and treatment of three cases of C. ulcerans infection is described. Two studies to determine C. ulcerans prevalence rates were undertaken: (a) a prospective study of nasal samples from healthy animals, 479 dogs and 72 cats; (b) a retrospective analysis of records of nasal samples collected over a 10-year period from 189 dogs and 64 cats affected by respiratory signs. RESULTS: Toxigenic C. ulcerans was isolated from four cats with nasal discharge while concurrent C. ulcerans and mecC methicillin-resistant S. aureus infection was detected in a dog suffering from chronic nasal discharge. Clinical features were not distinctive and all cases recovered following antimicrobial treatment. Multilocus sequence typing supported a common source for isolates from the shelter cats. Carriage rates of C. ulcerans in healthy animals were 0.42% (2/479) in dogs and 0.00% (0/72) in cats whereas in animals with signs of upper respiratory tract infection prevalence rates were 0.53% (1/189) in dogs and 6.25% (4/64) in cats. CLINICAL SIGNIFICANCE: Clinicians should be aware that dogs and cats can be infected with (or carriers of) toxigenic C. ulcerans Considering the potential zoonotic risk, assistance from medical and public health colleagues should be sought in confirmed cases.