Microbiota and metabolite alterations in pancreatic head and body/tail cancer patients.

Pancreatic head cancer (PHC) and pancreatic body/tail cancer (PBTC) have distinct clinical and biological behaviors. The microbial and metabolic differences in PHC and PBTC have not been studied. The pancreatic microbiota and metabolome of 15 PHC and 8 PBTC tissues and their matched nontumor tissues were characterized using 16S rRNA amplicon sequencing and untargeted metabolomics. At the genus level, Bradyrhizobium was increased while Corynebacterium and Ruminococcus were decreased in the PHC tissues (Head T) compared with the matched nontumor tissues (Head N) significantly. Shuttleworthia, Bacillus, and Bifidobacterium were significantly decreased in the PBTC tissues (Body/Tail T) compared with the matched nontumor tissues (Body/Tail N). Significantly, Ileibacterium was increased whereas Pseudoxanthomonas was decreased in Head T and Body/Tail T, and Lactobacillus was increased in Head T but decreased in Body/Tail T. A total of 102 discriminative metabolites were identified between Head T and Head N, which were scattered through linoleic acid metabolism and purine metabolism pathways. However, there were only four discriminative metabolites between Body/Tail T and Body/Tail N, which were related to glycerophospholipid metabolism and autophagy pathways. The differential metabolites in PHC and PBTC were commonly enriched in alpha-linolenic acid metabolism and choline metabolism in cancer pathways. Eubacterium decreased in Head T was positively correlated with decreased linoleic acid while negatively correlated with increased arachidyl carnitine and stearoylcarnitine. Bacillus decreased in Body/Tail T was negatively correlated with increased L-carnitine. These microbiota and metabolites deserve further investigations to reveal their roles in the pathogenesis of PHC and PBTC, providing clues for future treatments.

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 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.

Corynebacterium lipophilum sp. nov., a lipophilic bacterium isolated from clinical breast specimens and emended description of the species Corynebacterium pilbarense.

Two isolates (MC-18T and MC-17D), representing the Gram-stain-positive, facultatively anaerobic, irregular rod-shaped, non-motile, and non-spore-forming actinobacteria, were isolated from clinical breast specimens in Guangzhou, China. The growth of the isolates is enhanced by supplementing 1% Tween-80 on Luria Bertani agar. Optimal growth of the isolates was observed at 37 °C, pH 7-8, and with 1% (w/v) NaCl on Columbia blood agar. Pairwise comparison of the 16S rRNA gene sequences revealed that isolates MC-18T and MC-17D shared the highest sequence similarities with Corynebacterium liangguodongii 2184T (96.9%), which were lower than the threshold value for species delineation (98.65%). Phylogenetic dendrograms based on the 16S rRNA gene, rpoB gene, and core genomes indicated that two isolates formed a distinct lineage within the genus Corynebacterium. The estimated dDDH, ANIb, ANIm, and AAI values between strain MC-18T and its closely related strains were below the threshold values generally considered for recognizing a new species. The genome DNA G + C contents of both the isolates MC-18T and MC-17D are 60.6%. The two isolates have virulence-related genes of the VF classes of adhesion and antiphagocytosis, and also contain the antimicrobial resistance genes ErmX, mtrA, rpoB2, and RbpA. The major fatty acids (> 10%) of isolates MC-18T and MC-17D were C16:0, C18:1 ω9c, C18:0 and summed feature 5 (anteiso-C18:0 and/or C18:2 ω6,9c). The main respiratory quinone of strain MC-18T was MK-8(H2), and the polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, three unidentified glycolipids, an unidentified aminolipid, and four unidentified phosphoglycolipids. The two isolates lack mycolic acids in the cell envelope. Based on the above findings, the two isolates are considered to represent a novel species of the genus Corynebacterium, for which the name Corynebacterium lipophilum sp. nov. is proposed, with isolate MC-18T (= NBRC 115144T = CCTCC AB 2020201T) as the type strain. An emended description of the Corynebacterium pilbarense is also provided.

Succession and determinants of the early life nasopharyngeal microbiota in a South African birth cohort.

BACKGROUND: Bacteria colonizing the nasopharynx play a key role as gatekeepers of respiratory health. Yet, dynamics of early life nasopharyngeal (NP) bacterial profiles remain understudied in low- and middle-income countries (LMICs), where children have a high prevalence of risk factors for lower respiratory tract infection. We investigated longitudinal changes in NP bacterial profiles, and associated exposures, among healthy infants from low-income households in South Africa. METHODS: We used short fragment (V4 region) 16S rRNA gene amplicon sequencing to characterize NP bacterial profiles from 103 infants in a South African birth cohort, at monthly intervals from birth through the first 12 months of life and six monthly thereafter until 30 months. RESULTS: Corynebacterium and Staphylococcus were dominant colonizers at 1 month of life; however, these were rapidly replaced by Moraxella- or Haemophilus-dominated profiles by 4 months. This succession was almost universal and largely independent of a broad range of exposures. Warm weather (summer), lower gestational age, maternal smoking, no day-care attendance, antibiotic exposure, or low height-for-age z score at 12 months were associated with higher alpha and beta diversity. Summer was also associated with higher relative abundances of Staphylococcus, Streptococcus, Neisseria, or anaerobic gram-negative bacteria, whilst spring and winter were associated with higher relative abundances of Haemophilus or Corynebacterium, respectively. Maternal smoking was associated with higher relative abundances of Porphyromonas. Antibiotic therapy (or isoniazid prophylaxis for tuberculosis) was associated with higher relative abundance of anerobic taxa (Porphyromonas, Fusobacterium, and Prevotella) and with lower relative abundances of health associated-taxa Corynebacterium and Dolosigranulum. HIV-exposure was associated with higher relative abundances of Klebsiella or Veillonella and lower relative abundances of an unclassified genus within the family Lachnospiraceae. CONCLUSIONS: In this intensively sampled cohort, there was rapid and predictable replacement of early profiles dominated by health-associated Corynebacterium and Dolosigranulum with those dominated by Moraxella and Haemophilus, independent of exposures. Season and antibiotic exposure were key determinants of NP bacterial profiles. Understudied but highly prevalent exposures prevalent in LMICs, including maternal smoking and HIV-exposure, were associated with NP bacterial profiles. Video Abstract.

A conserved uORF in the ilvBNC mRNA of Corynebacterium species regulates ilv operon expression.

Computational methods can be used to identify putative structured noncoding RNAs (ncRNAs) in bacteria, which can then be validated using various biochemical and genetic approaches. In a search for ncRNAs in Corynebacterium pseudotuberculosis, we observed a conserved region called the ilvB-II motif located upstream of the ilvB gene that is also present in other members of this genus. This gene codes for an enzyme involved in the production of branched-chain amino acids (BCAAs). The ilvB gene in some bacteria is regulated by members of a ppGpp-sensing riboswitch class, but previous and current data suggest that the ilvB-II motif regulates expression by a transcription attenuation mechanism involving protein translation from an upstream open reading frame (uORF or leader peptide). All representatives of this RNA motif carry a start codon positioned in-frame with a nearby stop codon, and the peptides resulting from translation of this uORF are enriched for BCAAs, suggesting that expression of the ilvB gene in the host cells is controlled by attenuation. Furthermore, recently discovered RNA motifs also associated with ilvB genes in other bacterial species appear to carry distinct uORFs, suggesting that transcription attenuation by uORF translation is a common mechanism for regulating ilvB genes.

Corynebacterium guaraldiae sp. nov.: a new species of Corynebacterium from human infections.

Non-diphtheria Corynebacterium species (NDC) belonging to the human skin and mucosa microbiota are frequently neglected as contaminants. However, reports of human infections by Corynebacterium spp. have increased considerably in recent years. In this study, a group of six NDC isolates of urine (n = 5) and sebaceous cyst (n = 1) from two South American countries were identified at genus level or misidentified based on API® Coryne and genetic/molecular analyses. The 16S rRNA (99.09-99.56%) and rpoB (96.18-97.14%) gene sequence similarities of the isolates were higher when compared with Corynebacterium aurimucosum DSM 44532 T. Multilocus sequence analysis (MLSA) indicated that these six NDC isolates compose a distinctive phylogenetic clade. Genome-based taxonomic analysis with the whole-genome sequences was able to separate these six isolates from other known Corynebacterium type strains. Average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values between closely related type strains and the six isolates were considerably lower than the currently recommended threshold values for species circumscription. Phylogenetic and genomic taxonomy analyses indicated these microorganisms as a novel Corynebacterium species, for which we formally propose the name Corynebacterium guaraldiae sp. nov. with isolate 13T (= CBAS 827T = CCBH 35012T) as type strain.

Identification and Characterization of Corynaridin, a Novel Linaridin from Corynebacterium lactis.

Genome analysis of Corynebacterium lactis revealed a bacteriocin gene cluster encoding a putative bacteriocin of the linaridin family of ribosomally synthesized and posttranslationally modified peptides (RiPPs). The locus harbors typical linaridin modification enzymes but lacks genes for a decarboxylase and methyltransferase, which is unusual for type B linaridins. Supernatants of Corynebacterium lactis RW3-42 showed antimicrobial activity against Corynebacterium glutamicum. Deletion of the precursor gene crdA clearly linked the antimicrobial activity of the producer strain to the identified gene cluster. Following purification, we observed potent activity of the peptide against Actinobacteria, mainly other members of the genus Corynebacterium, including the pathogenic species Corynebacterium striatum and Corynebacterium amycolatum. Also, low activity against some Firmicutes was observed, but there was no activity against Gram-negative species. The peptide is resilient towards heat but sensitive to proteolytic degradation by trypsin and proteinase K. Analysis by mass spectrometry indicates that corynaridin is processed by cleaving off the leader sequence at a conserved motif and posttranslationally modified by dehydration of all threonine and serin residues, resulting in a monoisotopic mass of 3,961.19 Da. Notably, time-kill kinetics and experiments using live biosensors to monitor membrane integrity suggest bactericidal activity that does not involve formation of pores in the cytoplasmic membrane. As Corynebacterium species are ubiquitous in nature and include important commensals and pathogens of mammalian organisms, secretion of bacteriocins by species of this genus could be a hitherto neglected trait with high relevance for intra- and interspecies competition and infection. IMPORTANCE Bacteriocins are antimicrobial peptides produced by bacteria to fend off competitors in ecological niches and are considered to be important factors influencing the composition of microbial communities. However, bacteriocin production by bacteria of the genus Corynebacterium has been a hitherto neglected trait, although its species are ubiquitous in nature and make up large parts of the microbiome of humans and animals. In this study, we describe and characterize a novel linaridin family bacteriocin from Corynebacterium lactis and show its narrow-spectrum activity, mainly against other actinobacteria. Moreover, we were able to extend the limited knowledge on linaridin bioactivity in general and for the first time describe the bactericidal activity of such a bacteriocin. Interestingly, the peptide, which was named corynaridin, appears bactericidal, but without formation of pores in the bacterial membrane.

Corynebacterium sp. 2-TD Mediated Toxicity of 2-Tridecanone to Helicoverpa armigera.

Cotton bollworm (Helicoverpa armigera) is a Lepidopteran noctuid pest with a global distribution. It has a wide range of host plants and can harm cotton, tomato, tobacco, and corn, as well as other crops. H. armigera larvae damage the flower buds, flowers, and fruits of tomato and cause serious losses to tomato production. Tomato uses the allelochemical 2-tridecanone to defend against this damage. So far, there have been no reports on whether the adaptation of H. armigera to 2-tridecanone is related to its symbiotic microorganisms. Our study found that Corynebacterium sp. 2-TD, symbiotic bacteria in H. armigera, mediates the toxicity of the 2-tridecanone to H. armigera. Corynebacterium sp. 2-TD, which was identified by 16S rDNA gene sequence analysis, was screened out using a basal salt medium containing a unique carbon source of 2-tridecanone. Then, Corynebacterium sp. 2-TD was confirmed to be distributed in the gut of H. armigera by quantitative PCR (qPCR) and fluorescence in situ hybridization (FISH). The survival rate of H. armigera increased by 38.3% under 2-tridecanone stress after inoculation with Corynebacterium sp. 2-TD. The degradation effect of Corynebacterium sp. 2-TD on 2-tridecanone was verified by ultra-high-performance liquid chromatography (UPLC). Our study is the first to report the isolation of gut bacteria that degrade 2-tridecanone from the important agricultural pest H. armigera and to confirm bacterial involvement in host adaptation to 2-tridecanone, which provides new insights into the adaptive mechanism of agricultural pests to host plants.

Genomic differences among strains of Corynebacterium cystitidis isolated from uterus of camels.

INTRODUCTION: Members of the Corynebacterium cystitidis species are usually isolated from kidney and urine of cow having pyelonephritis. Nevertheless, we have isolated Corynebacterium cystitidis for the first time from uterus of camels, extending the type of mammalian host for this species. Furthermore, it remains unknown whether there are significant genetic variations between strains isolated from different host species and anatomic sites. In this perspective, we investigated the genomic diversity of Corynebacterium cystitidis species, whose pan genome remain unexplored to date. METHODOLOGY: Thus, we sequenced and compared the genomes of five Corynebacterium cystitidis of camel origin and a public genome of cow associated Corynebacterium cystitidis. RESULTS: Results revealed open pan genome of 4,038 gene clusters and horizontal gene transfer played a role in the extensive genetic diversity. Further, we found an obvious distinction between cow and camel associated C. cystitidis via phylogenomic analysis and by average nucleotide identity value of 95% between the two distant lineages and > 99% within camel associated C. cystitidis strains. Moreover, our data supports the hypothesis that the gene repertoire of cow associated Corynebacterium cystitidis developed so as to become more adaptable to the urine milieu. These genetic potentials are specifically evident for genes required for benzoate breakdown, iron transport, citrate and alanine utilization. CONCLUSIONS: Our findings confirm the differentiation of strains into camel lineage and cow lineage. These different niches, comprising the uterus of camel and urinary tract of cow probably played a role in shaping the gene repertoire of strains.

Corynebacterium macginleyi in the era of MALDI-TOF MS: epidemiology, susceptibility patterns and prevalence of co-infection.

Corynebacterium macginleyi has long been associated with ocular infections and has more recently been rarely implicated in systemic infections. There is a paucity of literature regarding the rate of C. macginleyi co-infection with other bacterial and viral pathogens and regarding the incidence of C. macginleyi infection in the paediatric population. In this study, we report 30 isolates of C. macginleyi of ocular origin from 26 patients, identified using matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS). The rates of co-isolation with bacterial and viral pathogens were 62% (n=16/26) and 39% (n=5/13), respectively, in this study. Of these, 13 patients had molecular testing performed as requested by treating clinicians for either the Chlamydia trachomatis/Neisseria gonorrhoeae PCR or herpes/enterovirus/adenovirus multiplex PCR. All isolates tested susceptible to linezolid, vancomycin and ciprofloxacin, with variable resistance to tetracycline, clindamycin and penicillin using EUCAST breakpoints.

Detection of in-frame mutation by IS30-family insertion sequence in the phospholipid phosphatidylglycerol synthase gene (pgsA2) of high-level daptomycin-resistant Corynebacterium striatum.

The emergence of high-level daptomycin (DAP)-resistant (HLDR) Corynebacterium striatum has been reported as a result of loss-of-function point mutations or premature stop codon mutations in a responsible gene, pgsA2. We herein describe the novel detection of an HLDR C. striatum clinical isolate, in which IS30-insertion was corroborated to cause destruction of pgsA2 gene. We isolated an HLDR C. striatum from a critically ill patient with underlying mycosis fungoides who had been treated with DAP for 10 days. With a sequence investigation, IS30-insertion was discovered to split pgsA2 in the HLDR C. striatum strain, which may cause disrupted phospholipid phosphatidylglycerol (PG) production. Future studies should survey the prevalence of IS-mediated gene inactivation among HLDR C. striatum clinical isolates.

New Insights of Corynebacterium kroppenstedtii in Granulomatous Lobular Mastitis based on Nanopore Sequencing.

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.

The effects of periodontitis associated microbiota on the development of oral squamous cell carcinoma.

Epidemiological data have shown that periodontal bacterial infection, periodontitis, and oral squamous cell carcinoma have close relationship on the disease progress and risk. However, the specific role of periodontal microbes and their mechanism in the development of oral squamous cell carcinoma is not yet clear. In our previous work, metagenomic Illumina Mi-seq analysis was used to identify tstructure and abundance of periodontital microbiome. Accoding to the results, we used Porphyromonas.spp. and Fusobacterium.spp. as the periodontitis positive microbiota; Neisseria.spp and Corynebacterium.spp as periodontitis negative microbiota (their average relative abundance were >5%). These representative strains of the above genus were used to infect OSCC cells to explore their effect on tumor cell biology behavior, and detect the expression level of the gene in related to inflammation, migration, invasion and cell cycle. We find that periodontitis positive correlated microbiota had a promoting effect on the development of oral squamous cell carcinoma in vitro by regulating mRNA and protein expression of IL-6, IL-8, MMP-9 and Cyclin-D1. Periodontitis negative correlated microbiota had suppression effect on the development of oral squamous cell carcinoma in vitro analysis.

The bacterial iron sensor IdeR recognizes its DNA targets by indirect readout.

The iron-dependent regulator IdeR is the main transcriptional regulator controlling iron homeostasis genes in Actinobacteria, including species from the Corynebacterium, Mycobacterium and Streptomyces genera, as well as the erythromycin-producing bacterium Saccharopolyspora erythraea. Despite being a well-studied transcription factor since the identification of the Diphtheria toxin repressor DtxR three decades ago, the details of how IdeR proteins recognize their highly conserved 19-bp DNA target remain to be elucidated. IdeR makes few direct contacts with DNA bases in its target sequence, and we show here that these contacts are not required for target recognition. The results of our structural and mutational studies support a model wherein IdeR mainly uses an indirect readout mechanism, identifying its targets via the sequence-dependent DNA backbone structure rather than through specific contacts with the DNA bases. Furthermore, we show that IdeR efficiently recognizes a shorter palindromic sequence corresponding to a half binding site as compared to the full 19-bp target previously reported, expanding the number of potential target genes controlled by IdeR proteins.

Virulence of clinically relevant multidrug resistant Corynebacterium striatum strains and their ability to adhere to human epithelial cells and inert surfaces.

Corynebacterium striatum is a nosocomial pathogen which is increasingly associated with serious infections in both immunocompetent and immunocompromised patients. However, little is known about virulence factors and mechanisms that may enhance the establishment and long-term survival of Corynebacterium striatum. in the hospital environment. In this study, we investigated the ability of 22 multidrug-resistant C. striatum clinical isolates to adhere to human epithelial cells and to produce biofilm on polystyrene plates, glass and various tracheostomy tubes. We also tested the virulence of these strains on the nematode Caenorhabditis elegans. They showed good adhesion to epithelial human cells after 180 min of infection. The 22 C. striatum were able to produce biofilms on positively and negatively charged abiotic surfaces at 37 °C. They were also able to infect and to kill Caenorhabditis elegans after 5 days of infection. The virulence condition was associated with the presence of SpaDEF operon encoding pili in all strains. This study provides new insights on virulence mechanisms that may contribute to the persistence of C. striatum in the hospital environment, increasing the probability of causing nosocomial infections.

Newly Isolated Animal Pathogen Corynebacterium silvaticum Is Cytotoxic to Human Epithelial Cells.

Corynebacterium silvaticum is a newly identified animal pathogen of forest animals such as roe deer and wild boars. The species is closely related to the emerging human pathogen Corynebacterium ulcerans and the widely distributed animal pathogen Corynebacterium pseudotuberculosis. In this study, Corynebacterium silvaticum strain W25 was characterized with respect to its interaction with human cell lines. Microscopy, measurement of transepithelial electric resistance and cytotoxicity assays revealed detrimental effects of C. silvaticum to different human epithelial cell lines and to an invertebrate animal model, Galleria mellonella larvae, comparable to diphtheria toxin-secreting C. ulcerans. Furthermore, the results obtained may indicate a considerable zoonotic potential of this newly identified species.

Corynebacterium jeikeium-induced infective endocarditis and perivalvular abscess diagnosed by 16S ribosomal RNA sequence analysis: A case report.

INTRODUCTION: Corynebacterium jeikeium normally presents on human skin, and it is often judged as contamination when it is cultured from blood. C. jeikeium can cause infective endocarditis, especially, that associated with cardiac surgery and prosthetic valvular endocarditis. CASE REPORT: A 66-year-old Japanese male patient was diagnosed with C. jeikeium-induced infective endocarditis (IE) and perivalvular abscess after a coronary artery bypass grafting and aortic valve replacement with bioprosthesis; pyogenic spondylodiscitis was also observed. Patch repair for aortic valve annulus and re-Bentall procedure with bioprosthesis was performed for IE and perivalvular abscess. The causative bacterium was confirmed as C. jeikeium on 16S ribosomal RNA sequencing of surgical sample and positive blood culture. The patient underwent six weeks of intravenous antibacterial treatment with vancomycin and an additional two weeks of oral treatment with linezolid, following which, his condition improved. Corynebacterium jeikeium can cause infective endocarditis and perivalvular abscess, which is a more severe condition than IE. CONCLUSION: 16S ribosomal RNA sequencing is useful in diagnosing bacterial species that can cause contamination, such as Corynebacterium spp.

Factors associated with treatment duration and recurrence rate of complicated mastitis.

BACKGROUND: The incidence of mastitis has increased, and this disease can lead to long antibiotic courses and complications. Here, we aimed to identify the factors associated with antibiotic duration and recurrence of complicated mastitis. MATERIALS AND METHODS: This retrospective cohort study was conducted in a tertiary hospital in Taiwan. All hospitalized patients diagnosed with mastitis (ICD-9 code 611.0) from Jan. 1, 2012, to Dec. 31, 2016, were enrolled. Patient characteristics and clinical data were obtained from the medical charts. Recurrence was defined as mastitis within the first year after the discontinuation of antibiotics for at least 7 days. RESULTS: In total, 214 females with a median age of 37 years old (IQR 33-45) were enrolled. A total of 148 patients (69.2%) underwent debridement, and 122 (57.0%) underwent biopsy. Histopathological examinations revealed granulation tissue in 44.6% (62/139) of the patients. Positive cultures were obtained in 65.9% (141/214) of the patients. Coagulase-negative staphylococci (64/141, 45.4%) was the most common pathogen, followed by Corynebacterium species (42/141, 29.8%). The median hospitalization length and antibiotic course were 7 (IQR 4-13) and 37 days (IQR 22-77), respectively. Three patients died of breast cancer during treatment. The recurrence rate was 18.5% (39/211). Younger age, corynebacterial infection, and pregnancy were associated with longer treatment durations (P < 0.001, 0.003, <0.001). Corynebacterial infection was associated with a 2.16-fold (95% CI: 1.11-4.20) increase in recurrence after adjusting for age. CONCLUSION: Corynebacterial infection is associated with longer treatment courses and an increased recurrence rate of complicated mastitis. Therefore, specific treatments should be considered.