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This study aimed to test the effectiveness of Raman spectroscopy in the characterization of the degrees of physiological stress and virulence in clinical swab samples collected from patients affected by oral candidiasis. Raman experiments were conducted on a series of eight isolates, both in an as-collected state and after biofilm purification followed by 3 days of culture. The outputs were matched to optical microscopy observations and the results of conventional chromogenic medium assays. A statistically significant series of ten Raman spectra were collected for each clinical sample, and their averages were examined and interpreted as multiomic snapshots for albicans and non-albicans species. Spectroscopic analyses based on selected Raman parameters previously developed for standard Candida samples revealed an extreme structural complexity for all of the clinical samples, which arose from the concurrent presence of a variety of biofilms and commensal bacteria in the samples, as well as a number of other biochemical circumstances affecting the cells in their physiological stress state. However, three Raman algorithms survived such complexity, which enabled insightful classifications of Candida cells from clinical samples, in terms of their physiological stress and morphogenic state, membrane permeability, and virulence. These three characteristics, in turn, converged into a seemingly "fight or flight" response of the Candida cells. Although yet preliminary, the present study points out criticalities and proposes solutions regarding the potential utility of Raman spectroscopy in fast bedside analyses of surveillance samples. [ABSTRACT FROM AUTHOR]

To prevent nosocomial infection, it is important to screen for potential vancomycin‐resistant Enterococcus (VRE) among patients. In this study, we analyzed enterococcal isolates from inpatients in one hospital without any apparent outbreak of VRE. Enterococcal isolates were collected from inpatients at Hiroshima University Hospital from April 1 to June 30, 2021 using selective medium for Enterococci. Multilocus sequence typing, antimicrobial susceptibility testing, and whole‐genome sequencing were performed. A total of 164 isolates, including Enterococcus faecium (41 isolates), Enterococcus faecalis (80 isolates), Enterococcus raffinosus (11 isolates), Enterococcus casseliflavus (nine isolates), Enterococcus avium (12 isolates), Enterococcus lactis (eight isolates), Enterococcus gallinarum (two isolates), and Enterococcus malodoratus (one isolate), were analyzed. We found one vanA‐positive E. faecium, which was already informed when the patient was transferred to the hospital, nine vanC‐positive E. casseliflavus, and two vanC‐positive E. gallinarum. E. faecium isolates showed resistance to ampicillin (95.1%), imipenem (95.1%), and levofloxacin (87.8%), and E. faecalis isolates showed resistance to minocycline (49.4%). Ampicillin‐ and levofloxacin‐resistant E. faecium had multiple mutations in penicillin‐binding protein 5 (PBP5) (39/39 isolates) and ParC/GyrA (21/36 isolates), respectively. E. raffinosus showed resistance to ampicillin (81.8%), imipenem (45.5%), and levofloxacin (45.5%), and E. lactis showed resistance to ampicillin (37.5%) and imipenem (50.0%). The linezolid resistance genes optrA and cfr(B) were found only in one isolate of E. faecalis and E. raffinosus, respectively. This study, showing the status of enterococci infection in hospitalized patients, is one of the important information when considering nosocomial infection control of VRE. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is a commensal bacterium in humans, but it sometimes causes opportunistic infectious diseases such as suppurative skin disease, pneumonia, and enteritis. Therefore, it is important to determine the prevalence of S. aureus and methicillin‐resistant S. aureus (MRSA) in individuals, especially older adults. In this study, we investigated the prevalence of S. aureus and MRSA in the oral cavity and feces of residents in long‐term care facilities (LTCFs). S. aureus was isolated from the oral cavity of 61/178 (34.3%) participants, including 28 MRSA‐positive participants (15.7%), and from the feces of 35/127 (27.6%) participants, including 16 MRSA‐positive participants (12.6%). S. aureus and MRSA were isolated from both sites in 19/127 individuals (15.0%) and 10/127 individuals (7.9%), respectively. Among 19 participants with S. aureus isolation from both sites, 17 participants showed the same sequence type (ST) type. Then, we analyzed the correlation of S. aureus and MRSA in the oral cavity and rectum with the participant's condition. S. aureus and MRSA positivity in the oral cavity was significantly related to tube feeding, while there was no correlation of rectal S. aureus/MRSA with any factors. Our findings regarding the oral inhabitation of MRSA and its risk factors indicate the importance of considering countermeasures against MRSA infection in LTCFs. [ABSTRACT FROM AUTHOR]

Introduction: The prevalence of antimicrobial-resistant bacteria (ARB) in long-term care facilities (LTCFs) remains unclear. Furthermore, the effect of ARB colonization on the clinical outcomes of LTCF residents has not been explored. Methods: We conducted a prospective multicenter cohort study and investigated the residents (N = 178) of six Japanese LTCFs (three Welfare Facilities for the Elderly Requiring Long-term Care and three Geriatric Health Service Facilities) for oral and rectal carriage of ARB. The clinical outcomes of the residents were evaluated based on isolating bacterial strains and subjecting them to whole-genome sequencing. Results: Of the 178 participants, 32 belonging to Geriatric Health Service Facilities with no information on their clinical outcome were excluded, and the remaining 146 were followed up for at most 21 months. Extended-spectrum β-lactamases (ESBL)-producing Enterobacterales and Pseudomonas aeruginosa were detected in 42.7% (n = 76) and 2.8% (n = 5) of the rectal swabs and 5.6% (n = 10) and 3.4% (n = 6) of the oral swabs, respectively. Detection of ARB in the oral and rectal cavities showed remarkable association with enteral nutrition. Further, P. aeruginosa was significantly associated with an increase in mortality of the residents, but there were not significant association between ESBL-producing Enterobacterales and mortality. Core-genome phylogeny of P. aeruginosa revealed a wide-spread distribution of the isolated strains across the phylogeny, which included a cluster of ST235 strains with substantially higher biofilm formation ability than the other isolated P. aeruginosa strains. Discussion/Conclusion: This study is the first to investigate the carriage of both oral and rectal ARB, genomic relatedness and determinants of antimicrobial resistance in isolated strains, and clinical outcomes of LTCF residents. Our study provides the first direct evidence for the burden of antimicrobial resistance in LTCFs. [ABSTRACT FROM AUTHOR]

A novel staphyiolytic enzyme, ALE-1, is a glyeylglycine endopeptidase produced by Staphylococcus capitis EPK1. ALE-1 possesses seven histidines. Chemical modification studies using diethylpyrocarbonate and iodoacetic acid suggested that a histidine or tyrosine residue(s) in the molecule is important for the organism's staphylolytic activity. All of the histidine residues, one tyrosine, and one aspartic acid residue in the N-terminally truncated ALE-1 ([DELTA]N-term ALE-1) were systematically altered by site-directed mutagenesis, and the enzyme activities and metal contents of the variants were measured. Our studies indicated that His-150, His-200, His-231, His-233, and Asp-154 are essential for the enzyme activity of [DELTA]N-term [DELTA]LE-1. Except for His-150 and Asp-154, all of these amino acids were located within the 38-amino-acid region conserved among 11 proteins, including 5 staphylolytic endopeptidases. Inductively coupled plasma-mass spectrometric analysis of [DELTA]N-term [DELTA]LE-1 revealed that it contains one atom of zinc per molecule. Measurement of the zinc content of the mutant [DELTA]N-term [DELTA]LE-1 suggested that His-150 and -233 are important for zinc binding; their loss in these variant enzymes coincided with the loss of staphylolytic activity. These results strongly suggest that ALE-1 is a novel member of zinc metalloproteases.

Byline: Takuji Noguchi (1), Hideki Shiba (1), Hitoshi Komatsuzawa (2), Noriyoshi Mizuno (1), Yuushi Uchida (1), Kazuhisa Ouhara (1), Ryuji Asakawa (1), Seiji Kudo (1), Hiroyuki Kawaguchi (1), Motoyuki Sugai (2), Hidemi Kurihara (1) Keywords: Actinobacillus actinomycetemcomitans; gingival epithelial cells; prostaglandin E.sub.2; E-cadherin; [beta]-defensin-2 Abstract: The interaction between epithelial cells and microorganisms is the most important step in bacterial infections. Actinobacillus actinomycetemcomitans was suggested to play a significant role in the initiation of periodontitis because of its bacteriological characteristics. Prostaglandins (PG) mediate the inflammatory response. Human [beta]-defensin-2 (hBD-2) is an antimicrobial peptide and contributes to innate immunity. E-cadherin is responsible for an epithelial intercellular junction. In this study, we investigated the syntheses of PGE.sub.2 and E-cadherin and the expression of hBD-2 in human gingival epithelial cells (HGEC) following exposure to A. actinomycetemcomitans. The levels of PGE.sub.2 and cyclooxygenase-2, which are responsible for an increase in PGE.sub.2, were increased depending on bacteria exposure time. hBD-2 mRNA was induced by A. actinomycetemcomitans, while HGEC exposed to A. actinomycetemcomitans showed a decrease in E-cadherin levels. Etodolac, a selective cyclooxygenase-2 inhibitor reinforced the increase in hBD-2 mRNA levels by A. actinomycetemcomitans. Furthermore, the etodolac suppressed the decrease in E-cadherin levels. Thus, endogenous PGE.sub.2 is involved in the hBD-2 and E-cadherin responses of HGEC to A. actinomycetemcomitans. These findings suggest that the inflammatory and antimicrobial response of gingival epithelial cells to A. actinomycetemcomitans is involved in the initiation of periodontal inflammation. A. actinomycetemcomitans may destroy the mechanical epithelial barrier by destroying E-cadherin. Author Affiliation: (1) Department of Periodontal Medicine, Division of Frontier Medical Science, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan (2) Department of Bacteriology, Division of Molecular Medical Sciences, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan Article History: Registration Date: 20/10/2004