ABSTRACT Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen that occurs primarily among immunocompromised and chronically ill pa- tients. However, little is known about the genomic diversity of C. striatum, which contributes to its long-term persistence and transmission in hospitals. In this study, a total of 192 C. striatum isolates obtained from 14 September 2017 to 29 March 2018 in a hospital in Beijing, China, were analyzed by antimicrobial susceptibility testing and pulsed-ﬁeld gel electrophoresis (PFGE). Whole-genome sequencing was con- ducted on 91 isolates. Nearly all isolates (96.3%, 183/190) were MDR. The highest re- sistance rate was observed for ciproﬂoxacin (99.0%, 190/192), followed by cefo- taxime (90.6%, 174/192) and erythromycin (89.1%, 171/192). PFGE separated the 192 isolates into 79 pulsotypes, and differences in core genome single-nucleotide poly- morphisms (SNPs) partitioned the 91 isolates sequenced into four clades. Isolates of the same pulsotype were identical or nearly identical at the genome level, with some excep- tions. Two dominant subclones, clade 3a, and clade 4a, were responsible for the hospital-wide dissemination. Genomic analysis further revealed nine resistance genes mobilized by eight unique cassettes. PFGE and whole-genome sequencing revealed that the C. striatum isolates studied were the result mainly of predominant clones spreading in the hospital. C. striatum isolates in the hospital progressively acquired resistance to antimicrobial agents, demonstrating that isolates of C. striatum may adapt rapidly through the acquisition and accumulation of resistance genes and thus evolve into dominant and persistent clones. These insights will be useful for the prevention of C. striatum infection in hospitals.
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Background: Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro. Methods: C. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy.
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ABSTRACT Daptomycin, a last-line-of-defense antibiotic for treating Gram-positive infections, is experiencing clinical failure against important infectious agents, includ- ing Corynebacterium striatum. The recent transition of daptomycin to generic status is projected to dramatically increase availability, use, and clinical failure. Here we conﬁrm the genetic mechanism of high-level daptomycin resistance (HLDR; MIC ⫽ ⬎ 256 g/ml) in C. striatum, which evolved within a patient during daptomycin ther- apy, a phenotype recapitulated in vitro. In all 8 independent cases tested, loss-of- function mutations in phosphatidylglycerol synthase (pgsA2) were necessary and suf- ﬁcient for high-level daptomycin resistance. Through lipidomic and biochemical analysis, we demonstrate that daptomycin’s activity is dependent on the membrane phosphatidylglycerol (PG) concentration. Until now, the veriﬁcation of PG as the in vivo target of daptomycin has proven difﬁcult since tested cell model systems were not viable without membrane PG. C. striatum becomes daptomycin resistant at a high level by removing PG from the membrane and changing the membrane com- position to maintain viability. This work demonstrates that loss-of-function mutation in pgsA2 and the loss of membrane PG are necessary and sufﬁcient to produce high- level resistance to daptomycin in C. striatum.
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Aortic stent graft infection is a rare but disastrous com- plication associated with high mortality. Infection rates for graft repair of aortic aneurysm are unclear although a ranging from less than 1% to 6% has been reported [1-5]. Corynebacterium striatum is a gram-positive, aerobic, nonsporulating bacillus that is part of the normal flora of the skin and respiratory tract and has a low virulence thus, when seen in blood cultures it is usually considered a contaminant . Although it has rarely been implicated as a cause of disease, native valve endocarditis has occa- sionally been described [7,8].
Over a 12-month period, Corynebacterium striatum strains were isolated from clinical specimens from 14 patients admitted to a surgical intensive care unit. These isolates were identical by morphology and biotype and displayed the same antibiogram. Ten isolates were found to be the sole possible pathogen. These 10 isolates were from six patients, three of whom had signs of infection at the time of positive culture. Further typing was performed by random amplification of polymorphic DNA analysis, by which all strains were identical and were found to differ to various degrees from reference strains and from isolates found in clinical samples from other wards. In a case-control study the only independent risk factor for acquiring the strain was intubation for longer than 24 h (odds ratio, 20.09; 95% confidence interval, 2.29 to 176.09). The same strain was isolated from surfaces and from air sampled in the direct vicinity of infected patients but never from surfaces or air in other places of the ward. The strain was not isolated from the ventilators. The strain was cultured from the hands of personnel attending to infected patients, but no long-term carriers were found among members of the hospital personnel, suggesting transient carriage only. We conclude that C. striatum can cause serious noso- comial infections in surgical intensive care unit patients and may spread from patient to patient via the hands of attending personnel.
Case presentation: We present a case of 63-year-old man who presented with progressively worsening dyspnea on exertion and lower leg edema, and was diagnosed with heart failure. Transesophageal echocardiography (TEE) revealed that the left atrium was filled with a 2.7 cm × 2.6 cm mass. The patient, who had no signs of infection or related risk factors, was suspected of having a left atrial myxoma clinically. After excising the mass, the histopathology suggested thrombus with no myxocytes. Postoperatively, a fever appeared and C. striatum was isolated from the blood cultures. Although antibiotics were used, the symptoms of heart failure worsened gradually and echocardiography revealed valve vegetation. The patient underwent a second operation because of IE. Surprisingly, the mass was confirmed to be a bacterial vegetation due to C. striatum based on Gram staining at a 1000× magnification, although this was not noted on routine pathological examination of the two surgical specimens.
The C. striatum strains were cultured on blood agar plates for 18 hours at 37°C. The cultured colony was suspended in 200 µL of lysis buffer, incubated overnight at 37°C, and centrifuged for 5 minutes at 3,000 rpm. The pelleted bacteria were suspended in 500 µL of sterile water and boiled for 15 minutes for DNA extraction. C. striatum DNA was extracted using a bacterial AccuPrep Genomic DNA Extraction Kit (Bioneer, Daejeon, ROK). To amplify 16S rRNA, universal primers 16SF27 (5 ′ -AGAGTTTGATCMTGGCTCAG) and 16SR1492 (5 ′ -TACGGYTACCTTGTTACGACTT) were used, as previously described. 12 The purified PCR product was
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Blood cultures detected Prevotella spp., ovarian ab- scess cultures identified Prevotella and C. striatum, and vaginal and perineal skin cultures also revealed C. striatum. C. striatum was identified by using the API Coryne identification panel (bioMerieux, Marcy l’Etoile, France). Vaginal and ovarian abscess cultures were negative for Chlamydia trachomatis, Neisseria gonorrhoeae, and other microbes. Also, Chlamydia tra- chomatis and Neisseria gonorrhoeae were negative ac- cording to polymerase chain reaction. Based on these culture results, meropenem was changed to ampicillin/ sulbactam 3 g every 8 h, and vancomycin and minocy- cline were continued.
16. Rufael, D. W., and S. E. Cohn. 1994. Native valve endocarditis due to Corynebacterium striatum: case report review. Clin. Infect. Dis. 19:1054–1061. 17. Soriano, F., J. Zapardiel, and E. Nieto. 1995. Antimicrobial susceptibilities of Corynebacterium species and other non-spore-forming gram-positive ba- cilli to 18 antimicrobial agents. Antimicrob. Agents Chemother. 39:208–214. 18. Vaneechoutte, M., P. Riegel, D. de Briel, G. Verschraegen, A. D. Rouck, and G. Claeys. 1995. Evaluation of the applicability of amplified rDNA-restric- tion analysis (ARDRA) to identification of species of the genus Corynebac- TABLE 2. Differential phenotypic characteristics of C. amycolatum, C. minutissimum, and C. striatum (8, 11, 12, 15, 19)
To our Knowledge this is the first study to examine the regional distribution and localization of PREP protein by western Blot and immunohistochemistry successively in the brain of hyperamonemic rats. We confirmed that prep is expressed in Hippocampus, Cortex, striatum and cerebellum of control rats and we showed that HA Rats displayed an increase in prep expression protein levels . Our results show that PREP was present in the cortex, striatum, hippocampus and cerebellum, as has been described in several studies ,  . Those areas participate in cognitive and motor functions, such as the . Furthermore PREP is present in glutamatergic, gabaergic, and cholinergic systems  . Moreover hydrolysis of neuropeptides is the main function of PREP in the brain and changes in these neuropeptide levels have been reported in several neurodegenerative diseases ,  .
The present study also suggests that the NAc-co and the DLS play important roles in learning of the instrumental component. This conclusion agrees with a recent study reporting that the deficit in learning 2-way active avoidance seen in dopamine- deficient KO mice was reversed by restoration of dopamine signaling in the NAc, dorsal striatum, and amygdala, but not by restoration of DA signaling restricted to the ventral striatum and amygdala (Darvas et al. 2011). We observed impaired learning of 2-way active avoidance by NAc-co lesioned rats, a finding consistent with previous studies showing dopamine release during the first training sessions of this task (Wietzikoski, Boschen, Miyoshi, Bortolanza, Santos, Frank, Brandao, Winn, and Da Cunha, 2012), and that infusion of D1 (Wietzikoski et al. 2012) or D2 (Boschen, Wietzikoski, Winn, and Da Cunha, 2011) dopamine receptor antagonists into the rat NAc impaired learning of this task.
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With respect to the anticipatory phase, De Martino, Kumaran, Seymour and Dolan (2006) assessed the influence of BOLD response measured in the amygdala during framed decision-making in a gambling task. In framing tasks, researchers are interested in assessing whether changing the presentation of an outcome, but not the outcome itself, influences how the outcome is processed. Briefly, participants began the task with a particular sum of money and throughout the task made decisions regarding whether to opt to lose a fixed amount of money, or to gamble with the possibility of either keeping all of the money or losing all of the money. Importantly, the amount of money that participants could knowingly lose by selecting the sure option was framed differently throughout the task. In the gain condition, the sure option was framed in terms of how much of the original sum of money participants could keep, whereas in the loss condition, the sure option was framed in terms of how much of the original sum of money participants could lose. The probability associated with losing or keeping everything was displayed in each trial. The framing effect was associated with an increased propensity towards going with the sure option in positively framed trials, and with an increased propensity towards going with the gamble in negatively framed trials. Importantly, basolateral amygdala activity was found to be higher following risky decisions than safe decisions in negatively framed trials, whereas activation was greater following safe decisions as opposed to risky decisions in positively framed trials. Additionally, a recent study employing a probabilistic learning task in an MRI scanner by Watanabe, Sakagami, and Haruno (2013) found that the presentation of fearful emotive stimuli prior to reward- predicting cues increased prediction error-related activity within the ventral striatum, and that this effect was modulated by changes in activity within the amygdala. These results support incentive value models of basolateral amygdala function in instrumental learning, and suggest that the primary function of the basolateral amygdala is to adjust the
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relatedness groups were evident. One group comprised six strains of Rothia-like FCG4a and the type strain of R. dento- FIG. 1. Phylogenetic tree, including selected relevant Rothia-like, Corynebacterium-like, and Corynebacterium species organisms. The tree was rooted using R. dentocariosa as the outgroup. Bootstrap analysis was done with 1,000 resamplings; bootstrap values are indicated at some branch points. The scale bar represents a 2% difference in DNA sequence. The strain numbers and GenBank accession number for the sequences used in the study are shown. DMMZ, Department of Medical Microbiology, University of Zurich; DSM ⫽ DSMZ, Deutsche Sammlung von Mikroorganismen und Zellkulturen; NCTC, National Collection of Type Cultures.
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Coyle et al. (7) assigned 3 of the 10 ‘‘C. xerosis’’ reference strains examined in their study to the species C. striatum, 4 of the 10 strains belonged to some lipophilic Corynebacterium species (7, 17), and this report demonstrated that strain NCTC 7243 is C. amycolatum. In contrast to our results, Coyle et al. (7) assigned strains ATCC 373 and ATCC 7711 to different hybridization groups, i.e., separate species. However, our data indicating 100% homology within the 16S rRNA genes of both strains demonstrate that they most likely belong to the same species. The reason for this discrepancy is unclear. Profiles of whole-cell protein electrophoresis as well as the mycolic acid patterns were almost identical for strains ATCC 373 and ATCC 7711, thereby reinforcing the close relation between the two strains (8, 15).
horse serum for 1 h at room temperature. The brain sec- tions were then incubated in a primary antibody of MBP (1:500, Abcam, Cambridge, MA) at 4 °C overnight. After rinsing with PBS for three times, the brain sections were incubated with a biotinylated secondary antibody and Vectastain ABC solution (Vector Labs, Burlingame, CA) for 1 h. The brain sections were then examined under an optical microscope. Three fields in the peri-infarct region of the ipsilateral striatum and the corresponding contralat- eral striatum were imaged in each section. A total of five sections (taking every other section spaced 200 μm apart) were evaluated for each mouse. The mean integrated optical density (IOD) was measured by the ImageJ Pro Plus 6.0 software (Media Cybernetics, Bethesda, MO). The ratio of mean IOD between the ipsilateral and contralat- eral was used for further analysis.
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Corynebacterium tuberculostearicum is a lipophilic corynebacterium validly characterized in 2004. We provide clinical informa- tion on 18 patients from whom this organism was isolated. The majority of the patients were hospitalized and had a history of prolonged treatment with broad-spectrum antimicrobials. In 7 (38.9%) of the 18 cases, the isolates were found to be clinically relevant. The present report also includes detailed data on the biochemical and molecular identification of C. tuberculosteari- cum, as well as its identification by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). Our data demonstrate that routine biochemical tests do not provide reliable identification of C. tuberculostearicum. MALDI-TOF MS represents a helpful tool for the identification of this species, since all of the strains matched C. tuberculosteari- cum as the first choice and 58.3% (7/12) of the strains processed with the full extraction protocol generated scores of >2.000. Nevertheless, partial 16S rRNA gene sequencing still represents the gold standard for the identification of this species. Due to the challenging identification of C. tuberculostearicum, we presume that this organism is often misidentified and its clinical rele- vance is underestimated. The antimicrobial susceptibility profile of C. tuberculostearicum presented here reveals that 14 (87.5%) of the 16 strains analyzed exhibited multidrug resistance.
When this laboratory evaluated the API Rapid CORYNE identification system (Biome´rieux Vitek, Inc., Hazelwood, Mo.), it was discovered that reactions of Corynebacterium matruchotii had been omitted from its database (12). Since the database included most other recognized Corynebacterium species of hu- man origin, we suspected that the developers had encountered some unresolvable discrepancies with representative strains of this species. To explore this possibility, we purchased all strains of C. matruchotii available at the American Type Culture Col- lection (ATCC). Because a large body of work has been pub- lished on the possible role of C. matruchotii in the pathogenesis of dental plaque, caries, and periodontitis, we also included two additional strains of C. matruchotii that were used in many of these studies, namely strain L2 and Richardson’s strain 13 (22, 23).
Difficulties observed in the identification of C. coyleae, P. acnes, and Aureobacterium spp. could be overcome by mod- ifying database 2.0 accordingly. For example, as has been re- ported before, C. coyleae strains acidified glucose and ribose at 48 h rather than the suggested 24 h (5). Difficulties in reading enzymatic reactions (in particular, alkaline phosphatase, N- acetyl-b-glucosaminidase, and esculin hydrolysis) might be avoided by reading of the strips by different persons. Esculin hydrolysis can be verified by exposing the API Coryne strip to UV light; since esculin is a fluorescent compound, fluorescence is observed when the substance is not hydrolyzed. It should be noted that for taxonomic investigations 24 h of incubation might not be sufficient, as some carbohydrate acidifications may become positive only after an extended incubation period (e.g., acid production from mannitol by Corynebacterium mac- ginleyi). Acid production might also be delayed in many other strains of lipophilic corynebacteria. In addition, we would like to stress the importance of basic microbiological tests (e.g., colony morphology, consistency of colonies, and Gram stain of cells) for the differentiation of coryneform bacteria (e.g., dif- ferentiation of the previous CDC coryneform group ANF bac-
As mentioned, many laboratories do not routinely identify Co- rynebacterium species, because they are frequently isolated as con- taminants and their identification is challenging. In our labora- tory, the term “small non-spore-forming Gram-positive bacillus resembling Corynebacterium species” is often used for coryneform organisms, since it can be challenging to differentiate Corynebac- terium species from Turicella otidis, Arthrobacter species, Brevibac- terium species, Dermabacter hominis, Rothia dentocariosa, Exigu- obacterium acetylicum, Helcobacillus species, Oerskovia turbata, Cellulomonas species, Cellulosimicrobium species, Microbacterium species, Curtobacterium species, and Leifsonia aquatica using a simplistic strategy (8). For species-level identification, phenotypic testing such as with API Coryne (bioMérieux, Durham, NC) has been used. Sequencing-based methods targeting the 16S rRNA gene or rpoB give more precise species identification (11). Of these, rpoB sequencing is ideal but not commonly available; none of these methods is rapid.
The genus Corynebacterium is one of the largest genera in the coryneform group of bacteria (which consist of irregular gram-positive rods and aerobically growing, asporogenous, non-partially acid-fast bacteria). Originally, the genus Coryne- bacterium was created essentially to accommodate the diph- theria bacillus and some other species pathogenic for animals. Bergey’s Manual of Systematic Bacteriology listed only 17 Cory- nebacterium species; however, 11 new species were defined between 1987 and 1995 (6), and another 32 new species were described between 1996 and 2003. From 2001 to 2003, up to 13 new species were validly published (http://www.bacterio.cict.fr /c/corynebacterium.html). At present, the genus Corynebacte- rium contains more than 60 species, the vast majority of which have been isolated from human or animal samples. Chemot- axonomically, this genus includes species that possess wall che- motype IV (arabinose, galactose and meso-diaminopimelic acid), short-chain mycolic acids (approximately 22 to 36 carbon atoms), and DNA G⫹C contents ranging from 51 to 63 mol% (5, 6). The narrower definition of the genus Corynebacterium has resulted in the transfer of several species (Clavibacter, Rhodococcus, and Turicella) to other genera. However, there is still some evidence of heterogeneity within the genus Coryne- bacterium. For example, Corynebacterium amycolatum and Corynebacterium kroppenstedtii lack mycolic acids (1, 2), Cory- nebacterium afermentans and Corynebacterium auris exhibit G⫹C contents of more than 65 mol% (6). The use of molecu- lar genetic methods such as 16S rRNA gene (rDNA) sequence analysis has facilitated a much tighter circumscription of the genus, and the availability of comparative 16S rRNA gene sequence data with improved phenotypic data has resulted in much improved and more reliable species identification (14,