Synergistic interactions of essential oil components with antibiotics against multidrug-resistant Corynebacterium striatum.

AIM: In this study, it was aimed to examine the antibacterial activity of the essential oil components (EOCs), carvacrol (CAR), cinnamaldehyde (CIN), thymol (TH), alpha pinene (α-PN), eucalyptol (EU), limonene (LIM), and the antibiotics, linezolid (LZD), vancomycin (VAN), gentamicin (GEN), ciprofloxacin (CIP), clindamycin (CLN), and penicillin (PEN) against 50 multidrug resistant Corynebacterium striatum strains, and the synergistic interactions of CAR and CIN with the antibiotics against 10 randomly selected Coryne. striatum strains to explore synergistic interactions to determine if their combined use could enhance antibiotic activity and potentially reduce resistance. METHODS AND RESULTS: The activity of the EOCs and the antibiotics against Coryne. striatum strains isolated from clinical specimens, was examined by broth microdilution method. The synergistic interactions of the EOCs with the antibiotics against 10 randomly selected Coryne. striatum strains were determined by checkerboard method. EOCs, CIN, and CAR and antibiotics, LZD, VAN, GEN, CIP, and CLN were detected to have antibacterial activity against Coryne. striatum strains alone and either synergistic interactions were observed in combinations of the antibiotics with EOCs. CONCLUSIONS: All Coryne. striatum strains were determined to be susceptible to VAN and LZD and resistant to GEN, PEN, CIP, and CLN. Synergistic interactions were observed in all combinations of antibiotics tested with CAR and CIN.

Clinicopathological studies on ulcerative lymphangitis in cattle: Alterations in serum inflammatory cytokines, anti-microbial, organs functions, and oxidative stress-related biomarkers.

Background: Affection with Corynebacterium pseudotuberculosis (C. pseudotuberculosis) and development of cellulitis and/or abscess formation with cutaneous lymphangitis in cattle is rare to some extent, so literature about the biochemical changes that would accompany this infection is rare. Aim: In this context, the present study was designed to screen the effect of the infection with C. pseudotuberculosis cutaneous lymphangitis on the release of some immune molecules, organ functions, and redox state in Baladi cows. Methods: Fourteen Baladi cows from a small dairy farm in El-Behira, Egypt, were selected to complete this study. After bacteriological culture confirmation, seven of them were found suffering from cutaneous lesions due to infection with C. pseudotuberculosis (Diseased group), while the others were healthy (Healthy group). Serum samples were obtained to evaluate the presumptive changes in some clinicopathological parameters. Results: Serum analysis revealed a significant decrease in the levels of interferon-gamma and interleukin-17 as well as a significant decrement in the concentration of beta-defensin (ß-defensin) and lipocalin-2. While serum level of interleukin-10 recorded a significant increase in these animals when compared to healthy control animals. Concurrently, the affected animals recorded a significant elevation in serum levels of hepato-cardiac enzymes, urea, and creatinine in addition to disturbance in the serum redox state. Conclusion: In conclusion, infection with C. pseudotuberculosis cattle may disturb the defensive immune state, body organ function, and redox state of the animals.

Isolation and identification of a novel phage targeting clinical multidrug-resistant Corynebacterium striatum isolates.

Introduction: Over the past decade, Corynebacterium striatum (C. striatum), an emerging multidrug-resistant (MDR) pathogen, has significantly challenged healthcare settings, especially those involving individuals with weakened immune systems. The rise of these superbugs necessitates innovative solutions. Methods: This study aimed to isolate and characterize bacteriophages targeting MDR-C. striatum. Utilizing 54 MDR-C. striatum isolates from a local hospital as target strains, samples were collected from restroom puddles for phage screening. Dot Plaque and Double-layer plate Assays were employed for screening. Results: A novel temperate bacteriophage, named CSP1, was identified through a series of procedures, including purification, genome extraction, sequencing, and one-step growth curves. CSP1 possesses a 39,752 base pair circular double-stranded DNA genome with HK97-like structural proteins and potential for site-specific recombination. It represents a new species within the unclassified Caudoviricetes class, as supported by transmission electron microscopy, genomic evolutionary analysis, and collinearity studies. Notably, CSP1 infected and lysed 21 clinical MDR-C. striatum isolates, demonstrating a wide host range. The phage remained stable in conditions ranging from -40 to 55°C, pH 4 to 12, and in 0.9% NaCl buffer, showing no cytotoxicity. Discussion: The identification of CSP1 as the first phage targeting clinical C. striatum strains opens new possibilities in bacteriophage therapy research, and the development of diagnostic and therapeutic tools against pathogenic bacteria.

[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.

Novel tetracycline resistance gene tet(65) located on a multi-resistance Corynebacterium plasmid.

BACKGROUND: Corynebacterium (C.) sp. 22KM0430 related to C. oculi and isolated from a dog exhibited resistance to tetracycline, and its WGS analysis revealed a putative resistance gene on a 35 562-bp plasmid also harbouring the MLSB resistance gene erm(X). OBJECTIVES: To characterize the novel tetracycline resistance gene tet(65) and demonstrate its functionality by expression in C. glutamicum and Escherichia coli and plasmid curing of the host strain. METHODS: tet(65) was cloned with and without its repressor tetR(65) and expressed in C. glutamicum DSM20300 and E. coli DH5α. Plasmid was cured by non-selective passages. Minimal inhibitory concentrations (MICs) of tetracyclines were determined according to CLSI guidelines. Association of tet(65) with efflux was shown by the addition of reserpine to MIC assays. Phylogenetic position and transmembrane structure of Tet(65) were analysed using MEGA11 and DeepTMHMM. RESULTS: Tet(65) shows 73% amino acid identity with the closest related Tet(Z), contains 12 transmembrane domains and is structurally related to the Major Facilitator Superfamily. The tetracycline MICs decreased in the plasmid-cured strain and increased when tet(65) was expressed in C. glutamicum and in E. coli. The MICs of tetracycline decreased in the presence of reserpine indicating that tet(65) functions as an efflux pump. A GenBank search also identified tet(65) in C. diphtheriae and Brevibacterium (B.) casei and B. luteolum. CONCLUSIONS: A novel tetracycline efflux gene tet(65) was identified in a C. oculi related species and was also present in the human pathogen C. diphtheriae and in Brevibacterium species indicating broader potential for dissemination.

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.

Corynebacterium diphtheriae and Corynebacterium ulcerans: development of EUCAST methods and generation of data on which to determine breakpoints.

BACKGROUND: Evidence-based clinical susceptibility breakpoints have been lacking for antimicrobial agents used for diphtheria. OBJECTIVES: We aimed to evaluate broth microdilution and disc diffusion methods and create a dataset of MIC values and inhibition zone diameters (ZDs) from which breakpoints could be determined. METHODS: We included 400 recent clinical isolates equally distributed by species (Corynebacterium diphtheriae and Corynebacterium ulcerans) and by national surveillance programmes (France and Germany). Non-duplicate toxigenic and non-toxigenic isolates were chosen to enable the inclusion of a diversity of susceptibility levels for the 13 agents tested. Broth microdilution and disc diffusion, using EUCAST methodology for fastidious organisms, were used. RESULTS: The distributions of MIC and ZD values were largely in agreement among methods and countries. Breakpoints to allow categorization of WT isolates as susceptible, i.e. susceptible (S) or susceptible, increased exposure (I) were determined for 12 agents. The data supported a breakpoint for benzylpenicillin and amoxicillin of resistant (R) > 1 mg/L since WT isolates were inhibited by 1 mg/L or less. WT isolates were categorized as I (S ≤ 0.001 mg/L) for benzylpenicillin, emphasizing the need for increased exposure, and S (S ≤ 1 mg/L) for amoxicillin. Erythromycin breakpoints were set at S ≤ 0.06 mg/L and R > 0.06 mg/L. The corresponding ZD breakpoints were determined for all agents except amoxicillin, for which categorization was based on benzylpenicillin results. CONCLUSIONS: This work provided a large set of antimicrobial susceptibility data for C. diphtheriae and C. ulcerans, using a harmonized methodology. The dataset allowed EUCAST and experts in the diphtheria field to develop evidence-based breakpoints in January 2023.

The N-terminal domain is required for cell surface localisation of VapA, a member of the Vap family of Rhodococcus equi virulence proteins.

Rhodococcus equi pneumonia is an important cause of mortality in foals worldwide. Virulent equine isolates harbour an 80-85kb virulence plasmid encoding six virulence-associated proteins (Vaps). VapA, the main virulence factor of this intracellular pathogen, is known to be a cell surface protein that creates an intracellular niche for R. equi growth. In contrast, VapC, VapD and VapE are secreted into the intracellular milieu. Although these Vaps share very high degree of sequence identity in the C-terminal domain, the N-terminal domain (N-domain) of VapA is distinct. It has been proposed that this domain plays a role in VapA surface localization but no direct experimental data provides support to such hypothesis. In this work, we employed R. equi 103S harbouring an unmarked deletion of vapA (R. equi ΔvapA) as the genetic background to express C-terminal Strep-tagged Vap-derivatives integrated in the chromosome. The surface localization of these proteins was assessed by flow cytometry using the THE2122;-NWSHPQFEK Tag FITC-antibody. We show that VapA is the only cell surface Vap encoded in the virulence plasmid. We present compelling evidence for the role of the N-terminal domain of VapA on cell surface localization using fusion proteins in which the N-domain of VapD was exchanged with the N-terminus of VapA. Lastly, using an N-terminally Strep-tagged VapA, we found that the N-terminus of VapA is exposed to the extracellular environment. Given the lack of a lipobox in VapA and the exposure of the N-terminal Strep-tag, it is possible that VapA localization on the cell surface is mediated by interactions between the N-domain and components of the cell surface. We discuss the implications of this work on the light of the recent discovery that soluble recombinant VapA added to the extracellular medium functionally complement the loss of VapA.

Activity of biogenic silver nanoparticles in planktonic and biofilm-associated Corynebacterium pseudotuberculosis.

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.

Factores de riesgo asociados a osteomielitis por Corynebacterium striatum en pacientes con pie diabético / Risk factors associated with osteomyelitis due to Corynebacterium striatum in patients with diabetic foot

Objetivo Corynebacterium striatum (C. striatum) es un microorganismo emergente en la infección de pie diabético poco estudiado. El objetivo es evaluar los factores de riesgo (FR) relacionados con osteomielitis por C. striatum en paciente con pie diabético. Métodos Estudio casos-controles en la Unidad de Pie Diabético entre 2015 y 2021. Un número de 44 pacientes con osteomielitis por C. striatum (casos) y 44 con osteomielitis por microorganismo distinto (controles) fueron incluidos. Resultados Enfermedad arterial periférica (odds ratio [OR]: 2,8, p = 0,037), fibrilación auricular (OR: 3,7, p = 0,034), pie diabético isquémico (OR: 3,3, p = 0,020) y antibioterapia previa prolongada más de 14 días (OR: 3,4, p = 0,012) fueron FR para la osteomielitis por C. striatum. En el análisis multivariado la antibioterapia más de 14 días fue el único FR independiente (OR: 3,46; p = 0,017) para osteomielitis por C. striatum. Conclusiones La antibioterapia previa recibida durante más de 14 días es un FR independiente y estadísticamente significativo de osteomielitis por C. striatum en pacientes con pie diabético (AU)

Objective Corynebacterium striatum (CS) is an emerging micro-organism in diabetic foot infection for which there are currently few studies. The objective was to analyze the risk factors (RF) related to CS osteomyelitis in patients with diabetic foot. Methods A case–control study was conducted in the Diabetic Foot Unit between 2015 and 2021. Forty-four patients with osteomyelitis due to CS (cases) and 44 patients with osteomyelitis due a different micro-organism (controls) were included. Results Peripheral artery disease (OR: 2.8, p = 0.037), atrial fibrillation (OR: 3.7, p = 0.034), ischemic diabetic foot (OR: 3.3, p = 0.020) and previous prolonged antibiotic therapy more than 14 days (OR: 3.4, p = 0.012) were identified as RF for osteomyelitis due to CS. When performing the multivariate analysis antibiotic therapy >14 days was independent RF (OR: 3.46; p = 0.017). Conclusions Previous antibiotic therapy received more than 14 days is an independent and statistically significant RF for CS osteomyelitis in patients with diabetic foot (AU)

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.

Preliminary comparative genomics analysis among Corynebacterium kroppenstedtii complex necessitates a reassessment of precise species associated with mastitis.

AIMS: This study aimed to characterize the first complete genome of Corynebacterium parakroppenstedtii and clarify the evolutionary relationship in the Corynebacterium kroppenstedtii complex (CKC) by using comparative genomics analysis. METHODS AND RESULTS: The genome of isolate yu01 from a breast specimen was sequenced, and 35 CKC genomes were collected. Analysis of 16S rRNA, rpoB, and fusA suggested ambiguous identification, whereas ANI analysis assigned isolate yu01 as Coryne. parakroppenstedtii. The fourth genospecies "Corynebacterium aliikroppenstedtii" was identified in CKC. Comparative genomics analysis suggested that the genomic arrangement in CKC was highly conserved. A total of 43 potential virulence genes and 79 species-specific genes were detected. Most genome-based phylogenetic analysis were incapable of resolving the interspecific evolutionary relationships among CKCs. A total of 20 core genes were found to be distinguishable in CKC. CONCLUSIONS: This study suggested the limited divergence and unavailability of normal single gene-based identification in CKC and questioned the precise species of strains associated with mastitis, identified as Coryne. kroppenstedtii in previous studies. The 20 genes showed potential to enhance the methods for the identification and epidemiological investigation of CKC.

Hard-to-heal peripheral wounds infected with Corynebacterium striatum: a prospective study.

OBJECTIVE: To investigate Corynebacterium striatum as a nosocomial pathogen infecting hard-to-heal peripheral wounds, such as skin wounds, soft tissue abscesses and osteomyelitis. As of 2023, the medical community were alerted against the risk of emerging systemic and central infections; on the other hand literature on peripheral cutaneous regions is still scarce. METHOD: In this study, two groups of patients with similar lesions which were infected were compared: one group with the presence of the coryneform rod, the other without. RESULTS: In total, Corynebacterium striatum was cultured from 62 patients and 131 samples. Corynebacterium striatum infection correlated well with the presence of: foot ulcer; venous leg ulcer; altered ambulation and/or altered foot loading; peripheral vascular and arterial disease; hospitalisation; malignancy; spinal cord injury; and recent administration of antibiotics (p<0.05 for all associations). Patients with Corynebacterium striatum had a lower overall survival rate compared to patients in the non-Corynebacterium striatum group (28.6 versus 31.6 months, respectively; p=0.0285). Multivariate analysis revealed that Corynebacterium striatum infection was an independent factor for poor prognosis (p<0.0001). CONCLUSION: In view of the findings of our study, Corynebacterium striatum appears to be an important opportunistic pathogen infecting peripheral tissues and complicating wound healing. Given its numerous and worrying virulence factors (such as multidrug resistance and biofilm production), particular attention should be given to this pathogen by professional wound care providers in nosocomial and outpatient environments.

Genomic characterization of the C. tuberculostearicum species complex, a prominent member of the human skin microbiome.

IMPORTANCE: Amplicon sequencing data combined with isolate whole genome sequencing have expanded our understanding of Corynebacterium on the skin. Healthy human skin is colonized by a diverse collection of Corynebacterium species, but Corynebacterium tuberculostearicum predominates on many skin sites. Our work supports the emerging idea that C. tuberculostearicum is a species complex encompassing several distinct species. We produced a collection of genomes that help define this complex, including a potentially new species we term Corynebacterium hallux based on a preference for sites on the feet, whole-genome average nucleotide identity, pangenomic analysis, and growth in skin-like media. This isolate collection and high-quality genome resource set the stage for developing engineered strains for both basic and translational clinical studies.

Antibiotic Treatment of Corynebacterium bovis-associated Clinical Disease in NSG Mice.

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- Prkdcscid Il2rgtm1Wjl /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.

Corynebacterium oculi-related bacterium may act as a pathogen and carrier of antimicrobial resistance genes in dogs: a case report.

BACKGROUND: The genus Corynebacterium comprises well-known animal and human pathogens as well as commensals of skin and mucous membranes. Species formerly regarded as contaminants are increasingly being recognized as opportunistic pathogens. Corynebacterium oculi has recently been described as a human ocular pathogen but has so far not been reported in dogs. CASE PRESENTATION: Here we present two cases of infection with a novel Corynebacterium sp., a corneal ulcer and a case of bacteriuria. The two bacterial isolates could not be identified by MALDI-TOF MS. While 16 S rRNA gene (99.3% similarity) and rpoB (96.6% identity) sequencing led to the preliminary identification of the isolates as Corynebacterium (C.) oculi, whole genome sequencing revealed the strains to be closely related to, but in a separate cluster from C. oculi. Antimicrobial susceptibility testing showed high minimal inhibitory concentrations of lincosamides, macrolides, tetracycline, and fluoroquinolones for one of the isolates, which also contained an erm(X) and tet-carrying plasmid as well as a nonsynonymous mutation leading to an S84I substitution in the quinolone resistance determining region of GyrA. CONCLUSIONS: While the clinical signs of both dogs were alleviated by antimicrobial treatment, the clinical significance of these isolates remains to be proven. However, considering its close relation with C. oculi, a known pathogen in humans, pathogenic potential of this species is not unlikely. Furthermore, these bacteria may act as reservoir for antimicrobial resistance genes also in a One Health context since one strain carried a multidrug resistance plasmid related to pNG3 of C. diphtheriae.

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.