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Background: Corynebacterium striatum (C. striatum) is a gram-positive, anaerobic bacillus found both environmentally and in human skin and nasal mucosa flora. It is reportedly the etiologic agent of community-acquired and nosocomial diseases and is significantly associated with bacteremia and medical endovascular devices. This is the rare case of mitral valve native valve endocarditis (NVE) caused by C. striatum occurring in a young adult without underlying structural heart disease or indwelling cardiovascular medical devices successfully treated with multidisciplinary therapy., Case Presentation: The patient was a 28-year-old female with no medical history. She was transferred our hospital due to sudden onset of vertigo and vomit. A computed tomography on day 2 revealed the hydrocephalus due to the cerebellar infarction, and she underwent posterior fossa decompression for cerebellar infarction. An angiography on day 8 revealed a left vertebral artery dissection, which was suspected be the etiology. Afterwards, a sudden fever of 39 degrees developed on day 38. She was diagnosed with aspiration pneumonia and treated with ampicillin/sulbactam but was still febrile at the time of transfer for rehabilitation. Treatment continued with levofloxacin, the patient had no fever decline, and she was readmitted to our hospital. Readmission blood cultures (3/3 sets) revealed C. striatum, and an echocardiogram revealed an 11 mm long mitral valve vegetation, leading to NVE diagnosis. On the sixth illness day, cardiac failure symptoms manifested. Echocardiography revealed mitral valve rupture. She was transferred again on the 11th day of illness, during which time her mitral valve was replaced. C. striatum was detected in the vegetation. Following surgery, she returned to our hospital, and vancomycin administration continued. The patient was discharged after 31 total days of postoperative antimicrobial therapy. The patient experienced no exacerbations thereafter., Conclusions: We report the rare case of C. striatum mitral valve NVE in a young adult without structural heart disease or indwelling cardiovascular devices., Clinical Trial Number: Not applicable., (© 2024. The Author(s).)

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., Competing Interests: Declarations of competing interest None., (Copyright © 2023 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Corynebacterium pseudotuberculosis is a gram-positive bacterium and is the etiologic agent of caseous lymphadenitis (CL) in small ruminants. This disease is characterized by the development of encapsulated granulomas in visceral and superficial lymph nodes, and its clinical treatment is refractory to antibiotic therapy. An important virulence factor of the Corynebacterium genus is the ability to produce biofilm; however, little is known about the characteristics of the biofilm produced by C. pseudotuberculosis and its resistance to antimicrobials. Silver nanoparticles (AgNPs) are considered as promising antimicrobial agents, and are known to have several advantages, such as a broad-spectrum activity, low resistance induction potential, and antibiofilm activity. Therefore, we evaluate herein the activity of AgNPs in C. pseudotuberculosis , through the determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), antibiofilm activity, and visualization of AgNP-treated and AgNP-untreated biofilm through scanning electron microscopy. The AgNPs were able to completely inhibit bacterial growth and inactivate C. pseudotuberculosis at concentrations ranging from 0.08 to 0.312 mg/mL. The AgNPs reduced the formation of biofilm in reference strains and clinical isolates of C. pseudotuberculosis, with interference values greater than 80% at a concentration of 4 mg/mL, controlling the change between the planktonic and biofilm-associated forms, and preventing fixation and colonization. Scanning electron microscopy images showed a significant disruptive activity of AgNP on the consolidated biofilms. The results of this study demonstrate the potential of AgNPs as an effective therapeutic agent against CL., Competing Interests: Vasco Azevedo and Debmalya Barh are Academic Editors for PeerJ., (©2024 Santos et al.)

Non-diphtheroid Corynebacterium sepsis is rare and has affected only immunocompromised or particularly predisposed patients so far. We present the first case of urosepsis caused by Corynebacterium aurimucosum in a 67-year-old woman, without any known immunodeficiencies and in absence of any immunosuppressive therapy, admitted to the hospital for fever and acute dyspnea. This work suggests a new approach in evaluating the isolation of Corynebacteria , especially if isolated from blood. In particular, it highlights the potential infectious role of C. aurimucosum (often considered a contaminant and only rarely identified as an etiological agent of infections) and its clinical consequences, detailing also interesting aspects about its microbiological diagnosis and relative therapy and clarifying contrasting data of literature.

Depending on the strain of immunodeficient mice, Corynebacterium bovis infection can be asymptomatic or cause transient or prolonged skin disease. C. bovis infection of NOD. Cg- Prkdc scid Il2rg tm1Wjl /SzJ (NSG) mice results in clinical skin disease that progresses in severity. Amoxicillin metaphylaxic and prophylaxic therapy prevents transmission and infection of mice after exposure to C. bovis and inhibits the growth of C. bovis isolates at therapeutic doses that are clinically achievable in mice. Amoxicillin is not efficacious for treatment of transient clinical skin disease in athymic nude mice, but the efficacy of amoxicillin treatment has not previously been characterized in C. bovis -infected NSG mice. In the current study, NSG mice were treated with amoxicillin beginning at 5 wk after exposure to C. bovis, at which time they had well-established clinical signs of disease. Clinical signs were scored to assess disease progression, regression, and reappearance. Our results showed that amoxicillin treatment for 3 or 6 wk reduced the clinical scores of NSG mice with C. bovis -associated clinical disease. In addition, withdrawal of treatment led to the recurrence of clinical signs. Collectively, our data suggest that amoxicillin treatment is effective in alleviating the clinical signs associated with C. bovis infection for the duration of treatment in NSG mice. Clinical intervention with antibiotics for C. bovis -infected NSG mice can be an option for management of C. bovis -related clinical disease either before or during facility-wide remediation efforts.

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., (© Commonwealth of Australia CC BY-NC-ND)

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 (x 2  = 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 (x 2  = 4.953, p = 0.026) were statistically significant. Age (Z = -1.046, p = 0.295), laterality (x 2  = 4.217, p = 0.121), time to presentation since the last delivery (x 2  = 0.028, p = 0.868), BMI (Z = -0.947, p = 0.344), lactation time (Z = -1.378, p = 0.168), parity (x 2  = 1.799, p = 0.180), gravida (Z = -0.144, p = 0.885), history of lactational mastitis or abscess (x 2  = 0.115, p = 0.734), local trauma (x 2  = 0.982, p = 0.322), hyperprolactinemia (x 2  = 0.706, p = 0.401), erythema nodosum (x 2  = 0.292, p = 0.589), and nipple discharge (x 2  = 0.281, p = 0.596) did not demonstrate statistical significance. Regarding recurrence related to therapeutic strategy, except for surgery combined with immunosuppressants (x 2  = 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% (x 2  = 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., (© 2023. The Author(s).)

Corynebacterium spp. are part of the human microbiome, but can cause the development of inflammatory diseases of various localization. Purpose - to evaluate the relationship between pathogenic properties and resistance to antimicrobial drugs (AMD) of Corynebacterium spp. from patients with inflammatory diseases of the respiratory tract. Strains of Corynebacterium spp. isolated from patients with inflammatory diseases of the respiratory tract (99 pcs.) and practically healthy individuals (33 pcs.). Isolates were identified by mass spectrometric method (MALDI-ToFMS), their adhesive and invasive activity on Hep-2 cells, cytopathic effect (CPE) in CHO-K1 cell culture, and resistance to antimicrobial drugs (AMD) were determined. Indicators of adhesion (3.65±0.679(CFU±m)x102/ml), invasion (1.72±0.230 (CFU±m)x102/ml), cytotoxicity (69.1±3.8% of dead CHO-K1 cells ) Corynebasterium spp. strains isolated from patients are higher (p≤0.05) than similar indicators in practically healthy people. 90.9% of isolates from patients had resistance to AMD, in most cases (57.6±4.9%) resistance to only one AMP was noted, less often to two (25.2±4.3%), three or more (8.08±2.7%). According to the results of correlation-regression analysis, pathogenic properties (adhesiveness, invasiveness, cytotoxicity) of Corynebacterium spp. strains isolated from patients are in close direct relationship with resistance to AMD. This indicates the importance of identifying strains of non-diphtheria corynebacteria resistant to AMDs, which, under the influence of developing resistance to AMDs, can increase their pathogenic potential, moving from commensalism to parasitism., Competing Interests: The authors declare no conflict of interest.

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%; χ 2  = 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., (© 2022. The Author(s).)

Corynebacterium bovis is an opportunistic pathogen of the skin of immunodeficient mice and is sensitive to oral antibiotics that reach therapeutic blood concentrations. However, prophylactic antibiotics are considered to be ineffective at preventing C. bovis infection. In addition, the effect of C. bovis on the skin microbiome (SM) of common immunodeficient mouse strains has yet to be characterized. Consequently, we evaluated whether oral prophylactic antibiotics prevent C. bovis infection after inoculation. An infectious dose of C. bovis was applied to the skin of Hsd:Athymic Nude (nude) and NOD. Cg- Prkdc scid Il2rgtm1Wjl /SzJ (NSG) mice. Mice were then housed individually and assigned randomly to receive either untreated drinking water ( Cb +Abx-group) or prophylactic amoxicillin-clavulanic acid in the drinking water (0.375 mg/mL) for 14 d ( Cb +Abx+group). A third treatment group of each mouse strain was uninoculated and untreated ( Cb -Abx-group). Mice from all groups were serially sampled by using dermal swabs to monitor C. bovis infection via quantitative real-time PCR and the SM via 16S rRNA sequence analysis. Fourteen days of prophylactic antibiotics prevented the perpetuation of C. bovis skin infection in both strains. Only the combination of C. bovis inoculation and oral antibiotics ( Cb +Abx+) significantly affected the SM of NSG mice at day 14; this effect resolved by the end of the study (day 70). In mice that did not receive antibiotics, C. bovis significantly altered the SM of nude mice but not NSG mice at days 14 and 70. These findings demonstrate the potential benefit of prophylactic antibiotics for prevention of C. bovis infection. However, indirect effect of antibiotics on commensal bacteria and potential effects on xenograft models must be considered.

Background: The etiology of granulomatous lobular mastitis (GLM) remains unknown. This study aimed to detect bacteria in GLM using Nanopore sequencing and identify the relationship between GLM and Corynebacterium kroppenstedtii ., Methods and Materials: The bacterial detection on fresh samples (including breast pus and tissue) of 50 GLM patients using nanopore sequencing and culture methods. The bacterial detection rate of participants with different stages were compared and analyzed. Formalin-fixed and paraffin-embedded (FFPE) tissues from 39 patients were performed on Gram staining to identify Gram-positive bacilli (GPB) within lipid vacuoles. Moreover, the clinicopathological characteristics of GLM patients in different bacterial subgroups were also conducted., Results: In 50 GLM patients, the detection rate of bacteria was 78% using nanopore sequencing method, especially in the early stage of GLM (over 80%), which was significantly higher than that using culture methods (24%, p  < 0.001). The dominant bacteria were Corynebacterium species (64%), especially for the Corynebacterium kroppenstedtii . The detection rate of C. kroppenstedtii in nanopore sequencing method (56%) was higher than that in culture methods (16%, p  < 0.001). Gram staining positive of bacteria in 7 patients, and 5 of them were C. kroppenstedtii . Thirty-one patients (31/39, 79.5%) exhibited typical histological structure of cystic neutrophilic granulomatous mastitis (CNGM), and eighteen patients detected with C. kroppenstedtii ., Conclusion: Nanopore sequencing showed rapid and accurate bacteria detection over culture method in GLM patients. GLM is not sterile inflammation and closely related to C. kroppenstedtii . CNGM was associated with Corynebacterium infection, especially for C. kroppenstedtii .

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.

The aim of this study was to clarify the clinical and microbiological characteristics of Corynebacterium bacteremia in hematological patients. We retrospectively reviewed the medical records of patients with Corynebacterium bacteremia from April 2013 to June 2018. The causative Corynebacterium species were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Drug susceptibility tests were performed using the broth microdilution method recommended by the Clinical and Laboratory Standards Institute. In total, 147 cases of Corynebacterium bacteremia were identified during the study period. Corynebacterium striatum was the most frequent pathogen. Catheter-related bloodstream infection was diagnosed in 19.7% of all patients, and moderate/severe oral or severe gastrointestinal mucosal impairment was detected in 19.7%. Polymicrobial infection was found in about 20% of cases, with Enterococcus faecium being the most frequent isolate. The overall 30-day mortality was 34.7% (51/147). Multivariate analysis showed that E. faecium co-infection (odds ratio (OR) 9.3; 95% confidence interval (CI) 2.1-40), systemic corticosteroids (OR 3.6; 95% CI 1.4-8.9), other immunosuppressive drugs (OR 0.32; 95% CI 0.13-0.76), and a Pitt bacteremia score ≥4 (OR 12; 95% CI 3.9-40) were significant risk factors for overall 30-day mortality. The drug susceptibility rates for beta-lactam antimicrobial agents were quite low. All isolates were susceptible to glycopeptides and linezolid. However, some C. striatum isolates were resistant to daptomycin. Corynebacterium bacteremia can occur in the presence of several types of mucosal impairment. Our drug susceptibility data indicate that Corynebacterium bacteremia in hematological patients could be treated by glycopeptides or linezolid., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

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., (Copyright © 2021 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: Corynebacterium urealyticum urinary tract infections can result in a rarely reported condition called encrusting cystitis whereby plaque lesions form on and within the urinary bladder mucosa. Chronic lower urinary tract signs manifest subsequent to the infection-induced cystitis and plaque-induced decreased bladder wall distensibility. Because of the organism's multidrug resistance and plaque forming capability, infection eradication can be difficult. While systemic antimicrobial therapy is the mainstay of treatment, adjunctive surgical debridement of plaques has been used with relative paucity in such cases, thereby limiting our understanding of this modality's indications and success rate. Consequently, this report describes the successful eradication of Corynebacterium urealyticum encrusting cystitis utilizing a unique timeline of medical and surgical treatments. Additionally, this represents the first reported veterinary case of a vasovagal reaction due to bladder overdistension., Case Presentation: A 6-year-old female spayed Miniature Schnauzer was evaluated for lower urinary tract clinical signs and diagnosed with Corynebacterium urealyticum encrusting cystitis. The infection was persistent despite prolonged courses of numerous oral antimicrobials and urinary acidification. A unique treatment timeline of intravenous vancomycin, intravesical gentamicin, and mid-course surgical debridement ultimately resulted in infection resolution. During surgery, while the urinary bladder was copiously flushed and distended with saline, the dog experienced an acute vasovagal reaction from which it fully recovered., Conclusions: Surgical debridement of bladder wall plaques should be considered a viable adjunctive therapy for Corynebacterium urealyticum encrusting cystitis cases failing to respond to systemic antibiotic therapy. The timing in which surgery was employed in this case, relative to concurrent treatment modalities, may be applicable in future cases of this disease as dictated on a case-by-case basis. If surgery is ultimately pursued, overdistension of the urinary bladder should be avoided, or at least minimized as much as possible, so as to prevent the possibility of a vasovagal reaction., (© 2021. The Author(s).)

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., Competing Interests: Disclosure: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Corynebacterium striatum , a bacterium that is part of the normal skin microbiota, is also an opportunistic pathogen. In recent years, reports of infections and in-hospital and nosocomial outbreaks caused by antimicrobial multidrug-resistant C. striatum strains have been increasing worldwide. However, there are no studies about the genomic determinants related to antimicrobial resistance in C. striatum . This review updates global information related to antimicrobial resistance found in C. striatum and highlights the essential genomic aspects in its persistence and dissemination. The resistome of C. striatum comprises chromosomal and acquired elements. Resistance to fluoroquinolones and daptomycin are due to mutations in chromosomal genes. Conversely, resistance to macrolides, tetracyclines, phenicols, beta-lactams, and aminoglycosides are associated with mobile genomic elements such as plasmids and transposons. The presence and diversity of insertion sequences suggest an essential role in the expression of antimicrobial resistance genes (ARGs) in genomic rearrangements and their potential to transfer these elements to other pathogens. The present study underlines that the resistome of C. striatum is dynamic; it is in evident expansion and could be acting as a reservoir for ARGs.

The aim of this study was to establish an evidence-based guideline for the antibiotic treatment of Corynebacterium striatum infections. Several electronic databases were systematically searched for clinical trials, observational studies or individual cases on patients of any age and gender with systemic inflammatory response syndrome, harboring C. striatum isolated from body fluids or tissues in which it is not normally present. C. striatum had to be identified as the only causative agent of the invasive infection, and its isolation from blood, body fluids or tissues had to be confirmed by one of the more advanced diagnostic methods (biochemical methods, mass spectrometry and/or gene sequencing). This systematic review included 42 studies that analyzed 85 individual cases with various invasive infections caused by C. striatum. More than one isolate of C. striatum exhibited 100% susceptibility to vancomycin, linezolid, teicoplanin, piperacillin-tazobactam, amoxicillin-clavulanate and cefuroxime. On the other hand, some strains of this bacterium showed a high degree of resistance to fluoroquinolones, to the majority majority of β-lactams, aminoglycosides, macrolides, lincosamides and cotrimoxazole. Despite the antibiotic treatment, fatal outcomes were reported in almost 20% of the patients included in this study. Gene sequencing methods should be the gold standard for the identification of C. striatum, while MALDI-TOF and the Vitek system can be used as alternative methods. Vancomycin should be used as the antibiotic of choice for the treatment of C. striatum infections, in monotherapy or in combination with piperacillin-tazobactam. Alternatively, linezolid, teicoplanin or daptomycin may be used in severe infections, while amoxicillin-clavulanate may be used to treat mild infections caused by C. striatum.

Caseous lymphadenitis (CLA) or pseudotuberculosis is a chronic zoonotic bacterial disease caused by Corynebacterium pseudotuberculosis, which affects livestock and humans. This study aimed to describe the pathology, bacteriology and confirm the identity of the pathogen by 16S rRNA gene sequencing in Camelus dromedarius. A total of 12 camels with suspected CLA in three regions of Abu Dhabi Emirate (Abu Dhabi, Al Ain and Al Dhafra), United Arab Emirate (UAE) were subjected to clinical and postmortem examinations from January 2015 to December 2020. Clinically, camels were emaciated and showed the presence of external caseous abscesses suggestive of CLA. Postmortem examination showed multiple abscesses of variable sizes with caseous material encapsulated by fibrous tissue in the liver, lungs, muscle, and lymph nodes. Following clinical and postmortem examination, blood, pus and different tissue samples were collected for subsequent analysis. Histopathological examination of all organs stained with Hematoxylin and Eosin (H&E) indicated a central caseo-necrotic core that was admixed with bacterial colonies and infiltration of chronic inflammatory cells, surrounded by a pyogenic membrane, and an outer fibrous connective tissue capsule. Bacterial culture identified the isolates of Corynebacterium pseudotuberculosis biotype ovis strain, and these isolates were shown to be sensitive to all antibiotics tested (penicillin, ampicillin, Co-trimoxazole, enrofloxacin and tetracycline). Moreover, the identity of the isolates was confirmed by partial sequencing of the 16S rRNA gene which showed a 100% identity to Corynebacterium pseudotuberculosis. Phylogenetic analysis based on 16S rRNA gene sequence clearly differentiates Corynebacterium pseudotuberculosis from other species of Corynebacterium. Briefly, this study provided the basic information for infection of Corynebacterium pseudotuberculosis in Camels and will help in controlling of this pathogen in the region., Competing Interests: The authors have declared that no competing interests exist.

Corynebacterium bovis , the causative agent of hyperkeratotic dermatitis in immunodeficient mice, is a significant problem in preclinical oncology research. Infection results in lifelong skin colonization and a decrease in successful engraftment of patient-derived xenograft tumor models. The use of antimicrobial agents for C. bovis is controversial in light of reports of poor efficacy and the possibility of selection for resistant strains. The purpose of this study was to describe the antimicrobial susceptibilities of C. bovis isolates obtained exclusively from immunodeficient rodents in order to aid in antimicrobial dose determination. Between 1995 and 2018, 15 isolates were collected from 11 research institutions across the United States. Antimicrobial susceptibility testing was performed for 24 antimicrobials commonly used against gram-positive bacteria. Our results provide an updated understanding of the susceptibility profiles of rodent C. bovis isolates, indicating little variability between geographically and temporally distant isolates. These results will facilitate appropriate antimicrobial use to prevent and treat C. bovis infections in immunodeficient rodents.

Purpose: To characterize diphtheroid corneal infections in eyes in the chronic phase of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN)., Methods: Observational case series., Results: Four eyes of 3 patients were included in this review. Each eye presented with persistent corneal epithelial defect with corneal thinning in the chronic phase of SJS/TEN. None of the epithelial defects were associated with stromal infiltration. The corneas were cultured at the time of workup of persistent epithelial defect (3 eyes) or at time of tectonic penetrating keratoplasty after perforation (1 eye). Cultures yielded abundant growth of Corynebacterium spp., including Corynebacterium jeikeium (n = 2), Corynebacterium glucuronolyticum (n = 1), and a multidrug-resistant Corynebacterium striatum isolate (n = 1). The ocular surface was stabilized with surgical intervention (1 eye) or with introduction of fortified topical antibiotic based on laboratory identification and susceptibility testing of the isolated organisms (3 eyes). Numerous risk factors for microbial keratitis were present in all 4 eyes., Conclusions: In eyes with a persistent corneal epithelial defect in the chronic phase of SJS/TEN, even in the absence of an infiltrate, corneal culture should be undertaken. Recognition and treatment of Corynebacterium spp. as opportunistic pathogens may lead to favorable outcomes in cases of clinically sterile ulceration during the chronic phase of SJS/TEN., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Corynebacterium simulans was first reported in 2000. Its characteristics such as isolation frequency, specimen types, and antimicrobial susceptibilities are poorly understood, because identification is difficult using conventional methods. We performed a retrospective observational study of 13 and 317 strains of C. simulans and C. striatum , respectively, isolated from consecutive patients at Nagoya University Hospital from January 2017 to December 2018. We analyzed patients' backgrounds, types of specimens, and antimicrobial susceptibilities. Antimicrobial susceptibilities were compared with those of C. striatum . The frequencies of isolation of C. simulans and C. striatum were 3.9% and 96%, respectively. C. simulans was not detected in specimens associated with mucous membranes, such as sputum and secretions from the craniocervical region, which were frequent for C. striatum . C. simulans was mainly detected in the skin (61.5%). All C. simulans isolates were susceptible to anti-MRSA drugs, as well as to numerous other antibiotics, including those that are orally administered. For example, C. simulans was significantly more susceptible to penicillin G, ceftriaxone, and ciprofloxacin than C. striatum (respective susceptibilities: 66.7% vs 5.4%, 50.0% vs 4.0%, 66.7% vs 5.9%). There was no significant difference between meropenem and erythromycin, although susceptibility to each was relatively high (100.0% vs 31.7%, 50.0% vs 11.9%). C. simulans was susceptible to numerous orally administered antibiotics and more susceptible to antimicrobial drugs than C. striatum . C. simulans was detected less frequently than C. striatum and was infrequently detected in specimens associated with mucous membranes. These characteristics will aid the selection of optimal antimicrobial therapies., Competing Interests: None

Here, we report a novel case of corneal ulcer in a 72-year-old patient with diabetes caused by Corynebacterium amycolatum This organism should not be ignored as a harmless commensal whenever it is isolated in pure form in repeat cultures of the specimen along with a leucocyte reaction in direct microscopic examination. Moreover, this organism is multidrug-resistant, so species identification of diphtheroids is important to start appropriate antibiotic therapy. There are very few published reports of ocular infection and none of corneal ulcer by this organism., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

A 35-year-old woman complained of an unpleasant odor for a few days after a change in foundation cream. The patient had previously undergone conjunctivo-dacryocystorhinostomy with a Jones tube fixed with non-absorbable suture. Slit-lamp examination revealed an orange-colored discharge in the tube. A culture test of the discharge showed Corynebacterium kroppenstedtii (1+), Aspergillus versicolor (1+), and Mycobacterium chelonae (1+). After medical treatment and suture removal, the discharge completely disappeared. This is the first reported case of a Jones tube infection following conjunctivo-dacryocystorhinostomy with multiple microorganisms, including C. kroppenstedtii .

Purpose: Nondiphtherial Corynebacterium species are normal residents of human skin and mucosa, including the conjunctiva and nose, but can cause conjunctivitis and keratitis. Recently, resistance against various classes of antibiotics has been reported in Corynebacterium. The present study investigated the type of species and antibiotic susceptibilities of the conjunctival and nasal Corynebacterium species., Methods: This study examined 183 strains of Corynebacterium species that were isolated from patients undergoing preoperative examinations for cataract surgery. Species were identified by RNA polymerase β-subunit-encoding gene (rpoB) sequencing. Antibiotic susceptibility tests were performed by the microdilution method according to the Clinical and Laboratory Standards Institute standard method M45., Results: Corynebacterium macginleyi was the most predominant species (84%; 46 of 55) in the conjunctiva. The 2 major species in the nasal cavity were Corynebacterium accolens and Corynebacterium propinquum (44% and 31%, respectively), followed by Corynebacterium pseudodiphtheriticum (8%), Corynebacterium jeikeium (7%), and C. macginleyi (3%). In contrast to other nasal Corynebacterium species, only C. macginleyi showed a high susceptibility to macrolides. However, among nonconjunctival Corynebacterium species, C. propinquum, was unique in having a high resistance rate to levofloxacin (29%), comparable with that observed in C. macginleyi (36%). Penicillin G and tobramycin showed good susceptibility in almost all strains., Conclusions: Drug resistance against fluoroquinolones and macrolides was observed in Corynebacterium species, with the antibiotic susceptibility profiles correlating with differences of the species and niche. Nasal and conjunctival Corynebacterium profiles of drug resistance suggest habitat segregation strictly at the species level.

Corynebacterium striatum is emerging as an opportunistic pathogen in immunocompromised hosts. End-stage renal disease remains an underappreciated state of immunocompromise. We present a series of individuals with end-stage kidney disease on hemodialysis who developed Corynebacterium striatum bacteremia, which was initially thought to be a contaminant, but eventually recognized as the culprit pathogen. We review the bacteriology of C. striatum, increasing resistance, as well as known cases of C. striatum bacteremia in the setting of end-stage renal disease. These cases highlight the importance of a high index of suspicion when interpreting bacterial cultures in patients with end-stage renal disease.

Despite constituting part of the human commensal flora, Corynebacterium pseudodiphtheriticum has been recognized as a potentially infectious agent, most frequently in immunocompromised patients or individuals with other morbidity factors, but significant association to comorbid states remains unproven. This study's purpose was to assess clinical significance, risk factors for infection and antimicrobial susceptibility of C. pseudodiphtheriticum isolates. A retrospective observational study was conducted. Relevance of isolation was determined by clinical, laboratory, and imaging criteria. Forty-nine isolates occurred in 47 episodes. Colonization was assumed in 12% and infection in 78%, of which 51% were nosocomial. Patients with infection were older, with male predominance; both age and gender were statistically significant (p < 0.05) between infection and colonization groups. Although dyslipidemia (58%), arterial hypertension (58%), invasive procedures (56%), and chronic lung disease (50%) were prevalent in the infection group, no comorbidity was a significant risk factor for infection compared with colonization. Charlson comorbidity index showed no statistically difference between groups. Mortality rate was 14% in infection. Respiratory samples were the main isolation product; all tested strains were susceptible to amoxicillin/clavulanate and vancomycin. Resistant strains were observed for clindamycin (77%) and erythromycin (48%). C. pseudodiphtheriticum isolation was associated with infection in most cases. Despite the high prevalence of comorbidities and invasive procedures, no factors other than age and gender were significantly associated with infection. Although C. pseudodiphtheriticum may constitute a contaminant or colonizer in clinical samples, positive cultures in patients with signs and symptoms consistent with infection should not be neglected.

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., (© 2020 British Small Animal Veterinary Association.)

Corynebacterium bovis is the causative agent of Corynebacterium -associated hyperkeratosis in immunocompromised mice. The resulting skin pathology can be profound and can be associated with severe wasting, making the animals unsuitable for research. Although the administration of antibiotics is effective in resolving clinical symptoms, antibiotics do not eradicate the offending bacterium. Furthermore, antibiotic use may be contraindicated as it can affect tumor growth and is associated with Clostridioides difficile enterotoxemia in highly immunocompromised murine strains. Lysins, which are lytic enzymes obtained from bacteriophages, are novel antimicrobial agents for treating bacterial diseases. The advantage of lysins are its target specificity, with minimal off-target complications that could affect the host or the biology of the engrafted tumor. The aim of this study was to identify lysins active against C. bovis . Chemical activation of latent prophages by using mitomycin C in 3 C. bovis isolates did not cause bacteriophage induction as determined through plaque assays and transmission electron microscopy. As an alternative approach, 8 lysins associated with other bacterial species, including those from the closely related species C. falsenii, were tested for their lytic action against C. bovis but were unsuccessful. These findings were congruent with the previously reported genomic analysis of 21 C. bovis isolates, which failed to reveal bacteriophage sequences by using the PHAST and PHASTER web server tools. From these results, we suggest C. bovis is among those rare bacterial species devoid of lysogenic bacteriophages, thus making the identification of C. bovis -specific lysins more challenging. However, C. bovis may be a useful model organism for studying the effects of antiphage systems.

Keratitis due to Candida parapsilosis or Corynebacterium macginleyi is uncommon. We present a patient with several risk factors who suffered two subsequent corneal infections caused by these pathogens and healed with topical conservative therapy. The important factor was the early detection of infection. Fluconazole solution administered topically as eye drops combined with regular debridement proved in this case a successful alternative to systemic antifungal treatment. With a perceived recurrence of the keratitis, one must take into account the involvement of other pathogens present. The previous use of an antifungal solution other than a conventional eye drop could be an additional risk factor for a second bacterial infection, but the benefits should still rule in favor of such a treatment.

Background: Intracranial infections with Corynebacterium striatum (C. striatum) have been described sporadically in the literature over the last two decades. However, C. striatum meningitis combined with multiple abscesses has not been published before., Case Presentation: In this report, we describe the clinical and imaging findings in a 54-year-old woman with meningitis caused by C. striatum and combined with suspected brain and lung abscesses. This patient who underwent multiple fractures and a recent cut presented with headache and paraphasia. C. striatum was isolated in cerebrospinal fluid and supposedly transmitted from the skin purulent wound through blood. The patient was treated with intravenous vancomycin and had a transient improvement, but died finally. Multiple abscesses, especially in the brain, could be a reason to explain her conditions were deteriorating rapidly., Conclusions: Note that C. striatum can cause life-threatening infections. Early identification and diagnosis, early administration of antibiotics to which the bacterium is susceptible, and treatment of complications will be beneficial in patients with C. striatum-related infection.

The purpose of this study was to investigate the high-level mupirocin resistance (HLMR) in Gram-positive bacteria isolated from companion animals. A total of 931 clinical specimens were collected from diseased pets. The detection of mupirocin-resistant bacteria and plasmid-mediated mupirocin resistance genes were evaluated by antimicrobial susceptibility tests, polymerase chain reactions, and sequencing analysis. Four-hundred and six (43.6%) bacteria were isolated and 17 (4.2%), including 14 staphylococci and 3 Corynebacterium were high-level mupirocin-resistant (MICs, ≥ 1,024 ug/mL) harboring mupA . Six staphylococci of HLMR strains had plasmid-mediated mupA -IS 257 flanking regions. The results show that HLMR bacteria could spread in veterinary medicine in the near future., Competing Interests: The authors declare no conflicts of interest., (© 2020 The Korean Society of Veterinary Science.)

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.

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., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

The aim of this study was to compare the efficacy of two dry-off protocols: (a) dry cow therapy using ciprofloxacin hydrochloride 400 mg followed by the administration of an internal teat sealant composed of 4 g of bismuth subnitrate, and (b) a positive control using dry cow therapy with 250 mg cephalonium followed by the administration of 2.6 g bismuth subnitrate internal teat sealant. A total of 578 Holstein cows selected from 7 commercial herds were randomly allocated into two groups at drying off: (a) ciprofloxacin hydrochloride 400 mg (CH) associated with ITS, n = 1112 mammary quarters/296 cows, or (b) positive control (PC) = cephalonium (250 mg) associated with ITS, n = 1058 mammary quarters/282 cows). A total of 1787 out of 2170 mammary quarters (82%) had negative culture at drying off. The microorganisms most frequently isolated at drying off were CNS (5.62%), Strep. uberis (1.9%), Corynebacterium spp. (1.8%), and Staphylococcus aureus (1.01%). A total of 465 mammary quarters experienced new intramammary infections (NIMIs), and the main microorganisms causing NIMI were CNS (21.94%), Strep. uberis (17.2%), and Pseudomonas spp. (9.7%). The CH protocol was not inferior to PC, as the cure risk of mammary quarters CH-treated was at the noninferiority limit. However, the mammary quarters treated by CH protocol had 24% and 31% lower risk of overall NIMI and NIMI caused by major pathogens, respectively, than mammary quarters dried with the PC protocol. In addition, the mammary quarters treated with CH protocol had a lower risk of CM through the first 60 DIM than those treated with PC protocol. Both DCT protocols showed similar odds of microbiological cure, but the CH protocol had greater prevention against NIMI during dry-off period.

Corynebacterium striatum, generally considered an opportunistic organism in humans, has recently been known to develop high-level daptomycin resistance (HLDR) shortly after drug exposure. To date, however, only several such clinical isolates have been described in the literature and clinical background of the resistant pathogen remains to be elucidated. Here, we report a case involving a C. striatum strain with HLDR harboring novel nucleotide mutations, together with a review of the relevant literature. To the best of our knowledge, this is the first well-investigated clinical report from Japan including a genetic investigation. Considering the rapid emergence of HLDR C. striatum in vitro experiment, there could be a number of underreporting cases. Scrupulous attention is required when administering daptomycin for the treatment of C. striatum infections, even if the organism has initially exhibited susceptibility., (Copyright © 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Corynebacterium striatum is a ubiquitous colonizer of human skin and mucous membranes. It is increasingly involved in infections, especially with prosthetic devices or in immunocompromised individuals. Microbiological diagnosis is challenging and bacterial resistance is a major concern. We performed a retrospective study of monomicrobial bone and joint infections (BJI) due to C. striatum in two referral centers from April 2012 to July 2017. We collected the patients' clinical and microbiological characteristics and outcomes. We also performed a literature review of BJI due to C. striatum. We identified 12 cases (nine prosthetic joint infections, one osteosynthetic device infection, one non-union, and one arthritis) in 11 patients, five of which were immunocompromised. Microbiological diagnosis was performed with prolonged culture media. Ten out of 12 strains were susceptible to aminopenicillin, a drug class not recommended for testing by the EUCAST/CASFM guidelines, and 8/12 patients were treated with amoxicillin-rifampicin. The cure rate was 8/12, after a median follow-up period of 487.5 days (IQR 140.3-1348.5). Twelve cases of BJI due to C. striatum were previously reported. Among them, 5/12 patients were immunocompromised, 3/12 cases were acute BJI, and 2/12 were device-related infections. The diagnosis was performed by PCR in one case, and 10/12 patients were treated with glycolipopeptides, with a cure rate of 11/12. We report the largest cohort of monomicrobial BJI with C. striatum. Determination of aminopenicillin susceptibility is essential since it is frequently active in our experience, even in BJI. The cure rate of this infection seems high.

Corynebacterium coyleae is part of the commensal microflora of the skin, urethra, mucous membranes, and genital tract. Isolates from patients with urinary tract infection (UTI) were reported, but the pathogenic potential of this species has not been defined yet. The aim of the study is to determine whether C. coyleae could be the etiological agent of UTI and to analyze its antibiotic susceptibility. Urine samples were cultured quantitatively according to accepted laboratory procedures. The identification of bacterial isolates was carried out using the Vitek MS (bioMérieux) and antibiotic susceptibility was tested using disc diffusion according to EUCAST guidelines. Between 1 January 2017 and 30 October 2018, a total of 39 C. coyleae strains were isolated. This represented 0.32% of all urine samples cultured in the laboratory during the collection period. The strains were isolated from samples obtained from 35 women and 3 men (age median for all-64 years). One female patient presented with C. coyleae in her urine twice at an interval of 21 months. In six cases of UTI, C. coyleae was isolated in monoculture. The isolates had the same resistance pattern. A total of 11 strains were obtained from cases with a clinical diagnosis of UTI. In 13 cases, the strain was cultured in a monoculture and in 28 cases with accompanying species. All strains were susceptible to vancomycin. However, resistance to ciprofloxacin was observed for 58.4% of the strains. Urine isolates of C. coyleae must be considered as contamination or normal flora in most cases (28/39, 72%). In the remaining cases, it can be considered as potential etiologic agents, mostly in women and especially in the 6 UTI cases where C. coyleae was found as the single culture-positive species. Several of these isolates demonstrate resistance to antibiotics commonly used in empiric treatment of urinary tract infections.