ABSTRACT
Bacteria produce and release small signal molecules, autoinducers, as an indicator of their cell density. The system, called a quorum-sensing (QS) system, is used to control not only virulence factors but also antibiotic production, sporulation, competence, and biofilm formation in bacteria. Different from antibiotics, QS inhibitors are expected to specifically repress the virulence factors in pathogenic bacteria without inhibiting growth or bactericidal effects. Therefore, since QS inhibitors have little risk of antibiotic-resistant bacteria emergence, they have been proposed as promising anti-bacterial agents. In the present study, we aimed to find new QS inhibitors that prohibit the signaling cascade of autoinducer 3 (AI-3) recognized by a QseCB two-component system that regulates some virulence factors of pathogens, such as enterohemorrhagic Escherichia coli (EHEC) and Salmonella enterica subsp. enterica serovar Typhimurium. We have established the method for QS-inhibitor screening using a newly constructed plasmid pLES-AQSA. E. coli DH5α transformed with the pLES-AQSA can produce ß-galactosidase that converts 5-bromo-4-chloro-3-indolyl ß-d-galactopyranoside (X-gal) into blue pigment (5-bromo-4-chloro-indoxyl) under the control of the QseCB system. By screening, Heyndrickxia coagulans (formerly Bacillus coagulans) 29-2E was found to produce an exopolysaccharide (EPS)-like water-soluble polymer that prohibits QseCB-mediated ß-galactosidase production without antibacterial activities. Further, the simultaneous injection of the 29-2E strain significantly improves the survival rate of Salmonella Typhimurium-infected silkworm larvae (from 0% to 83.3%), suggesting that the substance may be a promising inhibitor against the virulence of pathogens without risk of the emergence of antibiotic-resistant bacteria.
Subject(s)
Quorum Sensing , Salmonella typhimurium , Quorum Sensing/drug effects , Salmonella typhimurium/drug effects , Virulence , Bacillus/metabolism , Anti-Bacterial Agents/pharmacology , Lactones/pharmacology , Lactones/metabolism , Virulence Factors/metabolism , Virulence Factors/genetics , Animals , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Enterohemorrhagic Escherichia coli/drug effects , Enterohemorrhagic Escherichia coli/pathogenicity , Enterohemorrhagic Escherichia coli/metabolism , Biofilms/drug effects , Biofilms/growth & development , Homoserine/analogs & derivativesABSTRACT
Background: Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum are commensal bacteria that are associated with colonization and infection of the urogenital tract. However, colonization of the respiratory tract by these microorganisms in adults has not been fully investigated. Methods: Urine and respiratory tract samples (sputum, tracheal aspirates, and bronchoalveolar lavage) of patients aged 20-80 years were analyzed to detect the presence of M. hominis, U. parvum, and U. urealyticum using a conventional PCR method. The samples were submitted to the microbiological clinical laboratory of Hiroshima University Hospital from December 1, 2021 to May 31, 2022. Results: In total, 334 urine and 238 respiratory tract samples were analyzed. The overall detection rates of M. hominis, U. parvum, and U. urealyticum were 2.9%, 1.7%, and 2.3% in male urine; 7.0%, 13.8%, and 1.9% in female urine; 2.2%, 0%, and 2.2% in male respiratory tract; and 0%, 2.0%, and 0% in female respiratory tract, respectively. In urine samples, the detection rates of M. hominis, U. parvum, and U. urealyticum were significantly higher (p < 0.001) for women (29/159; 18.2%) than for men (10/175; 5.7%); however, in respiratory tract samples, the detection rates were not significantly different (p = 0.70) between women (2/101; 2.0%) and men (5/137; 3.7%). Further, both the urine and respiratory samples of 83 patients were analyzed. Three male samples were positive for M. hominis or U. urealyticum, and M. hominis and U. urealyticum were matched in both the urine and respiratory tract samples: M. hominis (n = 1), U. urealyticum (n = 1), M. hominis + U. urealyticum (n = 1). Conclusion: M. hominis, U. parvum, and U. urealyticum were detected in the respiratory tract of not only the young patients, but also of patients aged 50-60 years. Further studies are required to understand the relationship of these microorganisms in urogenital and respiratory tract samples with extra-genital infections.
ABSTRACT
Clinical isolates of Clostridioides difficile sometimes exhibit multidrug resistance and cause diarrhea after antibiotic administration. Metronidazole and vancomycin are often used as therapeutic agents, but resistance to these antibiotics has been found clinically. Therefore, the development of alternative antimicrobial agents is needed. Nisin A, produced by Lactococcus lactis, has been demonstrated to be effective against C. difficile infection. In this study, we evaluated the susceptibility of 11 C. difficile clinical isolates to nisin A and found that they could be divided into 2 groups: high and low susceptibility. Since CprABC and DltDABC, which are responsible for nisin A efflux and cell surface charge, respectively, have been reported to be related to nisin A susceptibility, we investigated the expression of cprA and dltA among the 11 strains. cprA expression in all strains was induced by nisin A, but dltA expression was not. The expression levels of both genes did not correlate with nisin A susceptibility in these clinical isolates. To evaluate cell surface charge, we performed a cytochrome C binding assay and found no relationship between charge and nisin A susceptibility. Then, we determined the whole genome sequence of each clinical isolate and carried out phylogenetic analysis. The 11 isolates separated into two major clusters, which were consistent with the differences in nisin A susceptibility. Furthermore, we found common differences in several amino acids in the sequences of CprA, CprB, and CprC between the two clusters. Therefore, we speculated that the different amino acid sequences of CprABC might be related to nisin A susceptibility. In addition, C. difficile strains could be divided in the same two groups based on susceptibility to epidermin and mutacin III, which are structurally similar to nisin A. These results suggest that genotypic variations in C. difficile strains confer different susceptibilities to bacteriocins.
Subject(s)
Anti-Bacterial Agents , Bacterial Proteins , Clostridioides difficile , Clostridium Infections , Drug Resistance, Bacterial , Nisin , Humans , Amino Acid Sequence , Anti-Bacterial Agents/pharmacology , Clostridioides difficile/drug effects , Microbial Sensitivity Tests , Nisin/pharmacology , Phylogeny , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolismABSTRACT
We retrospectively analyzed seven patients with Actinotignum schaalii bacteremia in a tertiary hospital in Japan. Pyelonephritis was the most frequent source of bacteremia, followed by Fournier's gangrene and pyometra. All patients with pyelonephritis had underlying urological conditions, ureteral stents, nephrostomy, ureteral stones, or ureterocele.
Subject(s)
Bacteremia , Fournier Gangrene , Pyelonephritis , Humans , Male , Japan/epidemiology , Tertiary Care Centers , Retrospective Studies , Bacteremia/diagnosis , Bacteremia/epidemiology , Bacteria, AnaerobicABSTRACT
Eggerthella lenta is an important cause of anaerobic bloodstream infections and is associated with high mortality. However, there are few reports of E. lenta infection in Japan. This study aimed to evaluate the clinical and microbiological characteristics of bacteremia caused by E. lenta in Hiroshima, Japan. We retrospectively analyzed E. lenta bacteremia patients at the Hiroshima University Hospital between January 2012 and December 2020. During the study period, 14 patients with E. lenta bacteremia were identified. All E. lenta isolates were cultured in anaerobic bottles, and the median time to blood culture positivity was 52.9 h. In most cases (85.6%), the source of E. lenta bacteremia was associated with intra-abdominal infections, and colon perforation was the most frequent source of E. lenta bacteremia (42.9%, n = 6). Antimicrobial susceptibility testing showed high minimal inhibitory concentrations (MIC) of piperacillin-tazobactam (TZP) and 100% susceptibility to ampicillin-sulbactam, carbapenems, and metronidazole. This study demonstrates that E. lenta bacteremia is associated with intra-abdominal infections, particularly colon perforation, and a high MIC of TZP. When gram-positive anaerobes are detected in the blood cultures of patients with severe intra-abdominal infections, clinicians should suspect E. lenta, and it may be better to change antimicrobial agents from TZP.
Subject(s)
Bacteremia , Actinobacteria , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Bacteremia/drug therapy , Humans , Japan/epidemiology , Microbial Sensitivity Tests , Retrospective Studies , Tertiary Care CentersABSTRACT
Staphylococcus pseudintermedius is commonly associated with skin and soft tissue infections in dogs. However, infections caused by S. pseudintermedius are only rarely reported in humans, and this pathogen is frequently misidentified as S. aureus. We herein report a case of an implanted port catheter system infection caused by methicillin-resistant S. pseudintermedius (MRSP) in a patient with hepatocellular carcinoma. The patient was also a dog owner. S. pseudintermedius was first identified using the Vitek2 system (BioMérieux). Whole-genome sequencing revealed that this MRSP was a sequence type 71-carrying staphylococcal cassette chromosome mec type III (ST71-SCCmec III) isolate.
Subject(s)
Dog Diseases , Methicillin-Resistant Staphylococcus aureus , Staphylococcal Infections , Vascular Access Devices , Animals , Anti-Bacterial Agents/pharmacology , Dog Diseases/diagnosis , Dogs , Humans , Methicillin Resistance , Methicillin-Resistant Staphylococcus aureus/genetics , Niacinamide/analogs & derivatives , Staphylococcal Infections/diagnosis , Staphylococcus , Staphylococcus aureusABSTRACT
BACKGROUND: The clinical effectiveness of ultraviolet light (UV) disinfection remains unclear. This study aimed to investigate the effect of adding pulsed xenon UV (PX-UV) disinfection to the terminal cleaning protocol on the rate of methicillin-resistant Staphylococcus aureus (MRSA) acquisition at a Japanese hospital. METHODS: The use of a PX-UV disinfection device was added to the manual terminal cleaning protocol applied after the discharge or transfer of patients treated in the intensive and high care units. We used a Poisson regression model to examine the incidence of MRSA acquisition, based on the study period, PX-UV intervention status, unit type, and the rate of consumption of alcohol-based hand rub (ABHR). RESULTS: Approximately 86% of the rooms in the intervention units were terminally disinfected with the PX-UV device. In the intervention units, the incidence of MRSA acquisition decreased from 3.56 per 1,000 patient-days in the nonintervention period to 2.21 per 1,000 patient-days in the intervention period. Moreover, the use of PX-UV disinfection decreased the risk of MRSA acquisition (incident rate ratio: 0.556; 95% confidence interval, 0.309-0.999; Pâ¯=â¯.0497). ABHR consumption did not affect the risk of MRSA acquisition. CONCLUSIONS: Adding PX-UV disinfection to terminal manual cleaning reduced the rate of MRSA acquisition.
Subject(s)
Cross Infection , Methicillin-Resistant Staphylococcus aureus , Cross Infection/prevention & control , Disinfection , Hospitals , Humans , Ultraviolet Rays , XenonABSTRACT
BACKGROUND: Contaminated environmental surfaces are important sources of transmission for healthcare-associated pathogens, including Clostridioides (Clostridium) difficile. The effectiveness of manual bleach cleaning and pulsed xenon ultraviolet (PX-UV) disinfection on C. difficile contamination of hospital room high-touch surfaces in Japan was evaluated. METHODS: The environmental surfaces of 20 C. difficile infection (CDI) isolation rooms were sampled immediately after CDI patients were discharged or transferred. High-touch surfaces were sampled before and after either bleach cleaning or PX-UV disinfection in addition to nonbleach cleaning. Changes in the number of C. difficile-positive samples and bacterial counts for each cleaning method were assessed. RESULTS: Overall, 286 samples were collected (bleach cleaning, 144 samples; PX-UV disinfection, 142 samples). Before cleaning, the positive rates of C. difficile were 27.8% and 31.0% in bleach cleaning and PX-UV disinfection, respectively. Both bleach cleaning and PX-UV disinfection significantly reduced overall C. difficile-positive samples (Pâ¯=â¯.018 and Pâ¯=â¯.002, respectively) and C. difficile colony-forming unit counts (Pâ¯=â¯.002 and Pâ¯=â¯.001, respectively). CONCLUSIONS: PX-UV disinfection in addition to manual nonbleach cleaning effectively reduces C. difficile contamination from high-touch surfaces. Further studies are warranted to evaluate the effect of PX-UV disinfection on CDI rates in Japanese hospitals.
Subject(s)
Clostridioides difficile , Cross Infection , Clostridioides , Clostridium , Cross Infection/prevention & control , Disinfection , Hospitals , Humans , Japan , Ultraviolet Rays , XenonABSTRACT
PURPOSE: Staphylococcus aureus is a relatively uncommon causative agent of urinary tract infection (UTI). However, the clinical features of S. aureus-related UTI are unclear. Thus, we aimed to clarify how patients with S. aureus bacteriuria develop UTI and determine the features and clinical risk factors of symptomatic S. aureus-related UTI. METHODS: We performed a retrospective study of patients at the Hiroshima University Hospital for whom S. aureus had been isolated from urine culture from January 2010 to December 2017. The characteristics (age, sex, body mass index, indwelling catheterization, renal stones, hydronephrosis, anticancer drug use, diabetes mellitus, steroid use, serum albumin, antibiotic use in the past 1 month, estimated glomerular filtration rate, benign prostate hyperplasia, and neurogenic bladder) of patients with UTI and those without UTI were compared, and the risk factors for S. aureus-related UTI were identified by multiple logistic regression model. RESULTS: A total of 286 patients with S. aureus bacteriuria were analyzed; 33 patients developed UTI. The causative pathogens were methicillin-sensitive S. aureus and methicillin-resistant S. aureus (MRSA) in 14 and 19 patients, respectively, who developed UTI. This study demonstrated that indwelling catheterization, hydronephrosis, and renal stones are significantly associated with S. aureus-related UTI (p = 0.01, odds ratio = 3.1; and p < 0.01, odds ratio = 7.0; and p = 0.02, odds ratio = 1.2; respectively) and hypoalbuminemia in MRSA-related UTI (p < 0.01). CONCLUSION: Paying attention to risk factors, specifically indwelling catheterization, renal stones, and hydronephrosis, will be an effective strategy for prevention of S. aureus-related UTI with persistent staphylococcal bacteriuria.
Subject(s)
Catheter-Related Infections/epidemiology , Catheter-Related Infections/etiology , Catheters, Indwelling/adverse effects , Hydronephrosis/complications , Kidney Calculi/complications , Staphylococcal Infections/epidemiology , Staphylococcal Infections/etiology , Staphylococcus aureus , Urinary Tract Infections/epidemiology , Urinary Tract Infections/etiology , Adolescent , Adult , Aged , Aged, 80 and over , Catheter-Related Infections/diagnosis , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Retrospective Studies , Risk Factors , Staphylococcal Infections/diagnosis , Urinary Tract Infections/diagnosis , Young AdultABSTRACT
BACKGROUND: Mobile phones may be contaminated with nosocomial pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to investigate the MRSA contamination rate on doctors' hospital-use-only mobile phones and the efficacy of 222-nm ultraviolet light (UV) disinfection. METHODS: We investigated the MRSA contamination rate of doctors' hospital-use-only mobile phones, as well as the reduction in MRSA counts on plastic plates and aerobic bacteria (AB) on mobile phones before and after exposure to 222-nm UV irradiation. RESULTS: Five (10%) of the 50 mobile phones investigated were contaminated with MRSA. Exposure to 0.1 mJ/cm2 222-nm UVC irradiation for 1.5 and 2.5 min (9 and 15 mJ/cm2) achieved mean log10 MRSA colony-forming units reductions of 2.91 and 3.95, respectively. Exposure to 9 mJ/cm2 222-nm UVC irradiation (0.1 mW/cm2 for 1.5 minutes) significantly reduced AB contamination on mobile phones (P < .001). CONCLUSIONS: The use of 222-nm UV disinfection resulted in effective in vitro reduction of MRSA and significantly reduced AB contamination of mobile phone surfaces.
Subject(s)
Cell Phone , Methicillin-Resistant Staphylococcus aureus , Disinfection , Hospitals , Humans , Ultraviolet RaysABSTRACT
Recently, a new rapid assay for the detection of tcdB gene of Clostridioides difficile was developed using the GENECUBE. The assay can directly detect the tcdB gene from stool samples without a purification in approximately 35 minutes with a few minutes of preparation process. We performed a prospective comparative study of the performance of the assay at eight institutions in Japan. Fresh residual stool samples (Bristol stool scale ≥5) were used and comparisons were performed with the BD MAX Cdiff assay and toxigenic cultures. For the evaluation of 383 stool samples compared with the BD MAX Cdiff assay, the sensitivity, and specificity of the two assays was 99.0% (379/383), 98.1% (52/53), 99.1% (327/330), respectively. In the comparison with toxigenic culture, the total, sensitivity, and specificity were 96.6% (370/383), 85.0% (51/60), and 98.8% (319/323), respectively. The current investigation indicated the GENECUBE Clostridioides difficile assay has equivalent performance with the BD MAX Cdiff assay for the detection of tcdB gene of C. difficile.
Subject(s)
Bacterial Proteins/genetics , Bacterial Toxins/genetics , Clostridioides difficile/genetics , Feces/microbiology , Clostridioides difficile/isolation & purification , Clostridium Infections/diagnosis , DNA, Bacterial/genetics , DNA, Bacterial/metabolism , Enterotoxins/genetics , Humans , Polymerase Chain Reaction/methods , Reagent Kits, Diagnostic , Repressor Proteins/genetics , Sensitivity and SpecificityABSTRACT
BACKGROUND: Contamination of healthcare environments by multidrug-resistant organisms (MDRO) and Clostridioides difficile is a risk for healthcare-associated infections. The efficacy of pulsed xenon ultraviolet (PX-UV) disinfection in healthcare environments has been described previously. However, there are few reports about PX-UV disinfection in Japan. The aim of this study was to investigate in vitro the efficacy of PX-UV disinfection of MDRO and C. difficile spores commonly isolated in Japanese hospitals. METHODS: We investigated reductions in microbial counts after exposure to PX-UV of the following clinically-isolated organisms on seeding agar plates: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium, carbapenemase-producing Klebsiella pneumoniae, extended spectrum ß-lactamase-producing Escherichia coli, multidrug resistant Acinetobacter baumannii, and C. difficile spores. We also visually assessed the attenuation of disinfection by shielding of MRSA and carbapenemase-producing K. pneumoniae from PX-UV exposure. RESULTS: PX-UV disinfection for 5 min induced >5-log colony-forming units (CFU)/cm2 growth inhibition of all the MDRO. PX-UV disinfection for 15 min induced >3-log CFU/cm2 growth inhibition of C. difficile spores. Where a plate was shielded from PX-UV exposure the bacteria showed confluent growth, but no colonies were observed on unshielded (exposed) parts of the plates. CONCLUSION: This study shows the efficacy of PX-UV disinfection against clinical MDROs. C. difficile spores were more resistant to PX-UV disinfection than vegetative bacteria. Further evaluation of the efficacy of PX-UV disinfection in reducing the contamination of real-world surfaces and the incidence of healthcare-associated infections is needed.
Subject(s)
Clostridioides difficile/radiation effects , Disinfection , Methicillin-Resistant Staphylococcus aureus/radiation effects , Ultraviolet Rays , Drug Resistance, Multiple, Bacterial , Humans , Infection Control , Spores, Bacterial/radiation effects , XenonABSTRACT
BACKGROUND: For residents of long-term care facilities (LTCFs), antimicrobial-resistant bacteria (ARB) are a risk factor, yet their oral colonisation, potentially leading to aspiration pneumonia, remains unclear. This study was undertaken to survey the prevalence, phenotypic characteristics, and molecular epidemiology of antimicrobial-resistant Gram-negative bacteria in the oral cavity of LTCF residents, and to analyse the risk factors for such carriers. METHODS: This study involved 98 residents of a LTCF in Hiroshima City, Japan, aged between 55 and 101 years. Oropharyngeal swabs were collected and plated on screening media for ESBL-producing and carbapenem-resistant bacteria; isolates were identified and tested for antibiotic susceptibility; biofilm formation was tested in vitro; identification of epidemic clones were pre-determined by PCR; resistance genes, sequence types, and whole-genome comparison of strains were conducted using draft genome sequences. Demographic data and clinical characterisations were collected and risk factors analysed. RESULTS: Fifty-four strains from 38% of the residents grew on screening media and comprised predominantly of Acinetobacter spp. (35%), Enterobacteriaceae spp. (22%), and Pseudomonas spp. (19%). All Escherichia coli isolates carried CTX-M-9 group and belonged to the phylogroup B2, O25:H4 ST131 fimH30 lineage. Six Acinetobacter baumannii isolates presented identical molecular characteristics and revealed more biofilm production than the others, strongly suggesting their clonal lineage. One Acinetobacter ursingii isolate displayed extensive resistance to various ß-lactams due to multiple acquired resistance genes. One Pseudomonas aeruginosa isolate showed exceptional resistance to all ß-lactams including carbapenems, aminoglycosides, and a new quinolone, showing a multidrug-resistant Pseudomonas aeruginosa (MDRP) phenotype and remarkable biofilm formation. Genome sequence analysis revealed this isolate was the blaIMP-1-positive clone ST235 in Japan. Strokes (cerebral infarction or cerebral haemorrhage) and percutaneous endoscopic gastrostomy tubes were recognised as risk factors for oral colonisation by ARB in the LTCF residents. CONCLUSIONS: ARB, as defined by growth on screening agar plates, which carried mobile resistance genes or elements or conferred high biofilm formation, were already prevalent in the oral cavity of LTCF residents. Health-care workers involved in oral care should be aware of antimicrobial resistance and pay special attention to transmission prevention and infection control measures to diminish ARB or mobile resistance elements dissemination in LTCFs.
Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial , Gram-Negative Bacteria/classification , Gram-Negative Bacterial Infections/epidemiology , Mouth/microbiology , Aged , Aged, 80 and over , Female , Genome, Bacterial , Gram-Negative Bacteria/drug effects , Gram-Negative Bacteria/genetics , Gram-Negative Bacteria/isolation & purification , Humans , Japan/epidemiology , Long-Term Care , Male , Microbial Sensitivity Tests , Middle Aged , Molecular Epidemiology , Pharynx/microbiology , Phylogeny , Prevalence , Whole Genome SequencingABSTRACT
Aeromonas dhakensis, a newly recognized species, is often misidentified as A. hydrophila, A. veronii, or A. caviae by commercial phenotypic tests. Limited data about A. dhakensis are available in Japan. We retrospectively analyzed the patients with monomicrobial Aeromonas bacteremia at Hiroshima University Hospital from January 2011 to December 2017, and species re-identification was conducted using rpoD and gyrB gene sequencing and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) system. Of the 19 strains from blood isolates, A. caviae (n = 9, 47.4%), A. dhakensis (n = 4, 21.1%), A. hydrophila (n = 3, 15.8%), and A. veronii (n = 3, 15.8%) were re-identified. A. dhakensis was phenotypically misidentified as A. hydrophila (n = 3, 75%) or A. sobria (n = 1, 25%). A. dhakensis was also misidentified as A. caviae (n = 2, 50%), A. hydrophila (n = 1, 25%), and A. jandaei (n = 1, 25%) in MALDI-TOF MS system. Malignancies (n = 12, 63.2%) and liver cirrhosis (n = 7, 36.8%) were common comorbidities. Biliary tract infection was the most frequent source of Aeromonas bacteremia (n = 11, 57.9%). The major source of A. dhakensis bacteremia was also biliary tract infection (n = 3, 75%), and the 14-day infection-related mortality of A. dhakensis was 25%. A. dhakensis isolates showed similar clinical characteristics, antimicrobial susceptibility, and mortality with those of other Aeromonas species isolates. This study demonstrated that A. dhakensis is not a rare cause of Aeromonas bacteremia, but is often misidentified as A. hydrophila in Hiroshima, Japan. Further studies should be conducted to identify the geographical distribution and clinical impact of A. dhakensis in Japan.
Subject(s)
Aeromonas/pathogenicity , Bacteremia/microbiology , Gram-Negative Bacterial Infections/microbiology , Adult , Aeromonas/genetics , Aeromonas/isolation & purification , Aged , Aged, 80 and over , Bacteremia/epidemiology , Biliary Tract Diseases/epidemiology , Comorbidity , Female , Gram-Negative Bacterial Infections/epidemiology , Humans , Japan/epidemiology , Liver Cirrhosis/epidemiology , Male , Microbial Sensitivity Tests , Middle Aged , Neoplasms/epidemiology , Retrospective Studies , Spectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationABSTRACT
Staphylococcus argenteus is a globally distributed cause of human infection; however, it has been misidentified as Staphylococcus aureus in diagnostic laboratories. Invasive infection caused by S. argenteus has been increasingly reported worldwide. However, there have been no reports on S. argenteus bacteremia in Japan. Therefore, we conducted a retrospective study to investigate the incidence of S. argenteus bacteremia at Hiroshima University Hospital between 2013 and 2017. S. argenteus was identified based on the absence of the crtM gene and multi-locus sequence typing. S. argenteus was identified in 2 of the 201 S. aureus blood culture isolates (1.0%). Both S. argenteus isolates belonged to sequence type 2250 harboring the staphylococcal enterotoxin Y gene (sey) and were susceptible to methicillin. One of them was penicillin-resistant, harboring a blaZ gene. The primary sites of infection were lower leg cellulitis and catheter-related blood stream infection. No patients died during hospitalization. This study suggested a low incidence of S. argenteus bacteremia in Japan when compared with reports from other countries. Further studies are necessary to investigate the prevalence of S. argenteus infection in Japan and the clinical impact of S. argenteus compared to S. aureus.
Subject(s)
Bacteremia , Staphylococcal Infections , Staphylococcus , Aged , Aged, 80 and over , Anti-Bacterial Agents/pharmacology , Bacteremia/epidemiology , Bacteremia/microbiology , Female , Humans , Incidence , Japan/epidemiology , Male , Multilocus Sequence Typing , Retrospective Studies , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Staphylococcus/drug effects , Staphylococcus/geneticsSubject(s)
Abscess/microbiology , Kidney Transplantation/adverse effects , Mycoplasma Infections/diagnosis , Mycoplasma hominis/isolation & purification , Pancreas Transplantation/adverse effects , Abdomen/diagnostic imaging , Adult , Anti-Infective Agents/pharmacology , Anti-Infective Agents/therapeutic use , Diabetes Mellitus, Type 1/diagnosis , Diabetes Mellitus, Type 1/therapy , Humans , Immunocompromised Host , Male , Mycoplasma Infections/drug therapy , Mycoplasma Infections/etiology , Mycoplasma Infections/microbiology , Mycoplasma hominis/drug effects , Postoperative Complications , Tomography, X-Ray Computed , Transplantation, HomologousABSTRACT
The emergence and spread of carbapenem-resistant gram-negative bacteria poses a serious threat to human health worldwide. Currently, little is known about the molecular mechanisms underlying carbapenem resistance and their prevalence among gram-negative bacteria in Egypt. In this study, we analyzed carbapenemase production in gram-negative bacteria isolated from hospitalized patients in Egypt in 2014. All isolates were subjected to phenotypic and genotypic susceptibility testing for carbapenem resistance. Our results indicated a high level of carbapenem-resistant gram-negative bacteria in Egypt, with 50.8% of the isolates harboring at least one carbapenem resistance gene. OXA-48-like and NDM-1 were the most prevalent carbapenemases, being detected in 49.2%, and 47.7% of carbapenemase-positive isolates, respectively, whereas Verona integron-encoded metallo-ß-lactamase (VIM) was detected in only 26.2% of carbapenemase-positive isolates. This study reports for the first time carbapenemase-producing Serratia marcescens, Morganella morganii, and blaVIM-1-like-producing Pseudomonas aeruginosa in Egypt. It is also the first demonstration of the coexistence of different carbapenemases, being detected in 21.5% of carbapenemase-positive isolates. Effective antibiotic supervision, regional surveillance, and early detection of carbapenemase producers are imperative to prevent their future spread to epidemic levels.
Subject(s)
Escherichia coli/genetics , Morganella morganii/genetics , Pseudomonas aeruginosa/genetics , Serratia marcescens/genetics , beta-Lactam Resistance/genetics , beta-Lactamases/genetics , Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Egypt/epidemiology , Enterobacteriaceae Infections/drug therapy , Enterobacteriaceae Infections/epidemiology , Enterobacteriaceae Infections/microbiology , Escherichia coli/classification , Escherichia coli/drug effects , Escherichia coli/isolation & purification , Escherichia coli Infections/drug therapy , Escherichia coli Infections/epidemiology , Escherichia coli Infections/microbiology , Gene Expression , Hospitals , Humans , Integrons , Microbial Sensitivity Tests , Morganella morganii/classification , Morganella morganii/drug effects , Morganella morganii/isolation & purification , Phylogeny , Pseudomonas Infections/drug therapy , Pseudomonas Infections/epidemiology , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/classification , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/isolation & purification , Serratia Infections/drug therapy , Serratia Infections/epidemiology , Serratia Infections/microbiology , Serratia marcescens/classification , Serratia marcescens/drug effects , Serratia marcescens/isolation & purification , beta-Lactamases/metabolismABSTRACT
Global spread and evolutionary links of an epidemic Clostridium difficile strain (PCR-ribotype 027) have been noted in recent decades. However, in Japan, no outbreaks caused by type 027 have been reported to date. A total of 120 C. difficile isolates from patients at 15 hospitals during non-outbreak seasons between 2011 and 2013 as well as 18 and 21 isolates collected from two hospitals in 2010 and 2009, respectively, in outbreak periods in Japan, were examined. Among these 120 isolates, Japan-ribotypes smz and ysmz (subtype variant of smz) were the most predominant (39.2 %) followed by Japan-ribotype trf (15.8 %). Types smz/ysmz and trf were also concurrently predominant at two hospitals in the outbreak settings. Out of the five binary toxin-positive isolates observed, only one was PCR-ribotype 027 and another PCR-ribotype 078. Type smz was later found to correspond to PCR-ribotype 018. High rates of resistance against gatifloxacin, moxifloxacin, erythromycin and clindamycin were observed in the PCR-ribotype 018 isolates. Interestingly, all trf isolates were toxin A-negative, toxin B-positive, but they did not correspond to PCR-ribotype 017, thus being assigned a new ribotype (PCR-ribotype 369). In conclusion, PCR-ribotypes 018 (smz) and 369 (trf) were identified as major circulating strains in both outbreak and non-outbreak settings in Japan. Given their epidemiological relevance, molecular investigations are warranted to clarify potential evolutionary links with related strains found elsewhere, such as PCR-ribotypes 018 and 017 from Europe and North America.
Subject(s)
Clostridioides difficile/classification , Clostridioides difficile/genetics , Clostridium Infections/epidemiology , Clostridium Infections/microbiology , Diarrhea/epidemiology , Diarrhea/microbiology , Ribotyping , Anti-Bacterial Agents/pharmacology , Clostridioides difficile/drug effects , Clostridioides difficile/isolation & purification , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Drug Resistance, Bacterial , Hospitals , Humans , Japan/epidemiology , Molecular Epidemiology , Molecular Sequence Data , Prevalence , Sequence Analysis, DNAABSTRACT
This in vitro study examined the combined effects of double antibacterial drugs against multidrug-resistant Pseudomonas aeruginosa (MDRP). The tested clinical isolates from Hiroshima University Hospital were 40 strains which met the criteria for MDRP, that is, the minimum inhibitory concentration (MIC) was > or = 16 microg/mL of meropenem, > or = 4 microg/mL of ciprofloxacin and > or = 32 microg/mL of amikacin. Using the original checkerboard plates for colistin (CL), arbekacin (ABK), aztreonam (AZT), rifampicin (RFP) and piperacillin (PIPC), MIC values were determined for single and double combinations. Based on the MIC values, fractional inhibitory concentration index values were calculated and the combined effects (synergy action or additive action) were evaluated. The three strongest drugs among the tested combinations were i) CL + RFP (synergy, 80.0%; additive, 17.5%), ii) RFP + ABK (synergy, 7.5%; additive, 70.0%) and iii) RFP + AZT (synergy, 5.0%; additive, 77.5%). In these cases, the arithmetic mean MIC value of each drug significantly decreased as follows: i) 1.38 microg/mL (alone) and 0.26 microg/mL (with RFP) for CL, 19.85 microg/mL (alone) and 1.85 microg/mL (with CL) for RFP; ii) 19.85 microg/mL (alone) and 7.53 microg/mL (with ABK) for RFP, 8.87 microg/mL (alone) and 2.79 microg/mL (with RFP) for ABK; iii) 19.85 microg/mL (alone) and 10.15 microg/mL (with AZT) for RFP, 28.3 microg/ mL (alone) and 6.65 microg/mL (with RFP) for AZT. Of 40 strains, metallo-beta-lactamase and aminoglycoside 6'-N-acetyltransferase were found in 20 and 37 strains, respectively; however, no significant influence of these factors was observed on the combined effects of i), ii) and iii). The results of this study provide an in vitro rationale for RFP plus CL, ABK or AZT as an effective combination therapy for MDRP infections, although the results should be verified and compared with other antibacterial drugs in further studies.