Ayaka Tsukimori

Fulminant colitis from Clostridium difficile infection, the epidemic strain ribotype 027, in Japan.

In December 2012, a 32-year-old woman with no previous medical history and no previous antibiotic treatment had a fever and diarrhea 2 days after a cesarean section in which cefazolin was used as a prophylactic antimicrobial agent. She was transferred to our hospital 5 days after the cesarean for severe colitis. A rapid test of stool for Clostridium difficile toxin A and B was positive. Although oral vancomycin (0.5-2.0 g/day) and intravenous immunoglobulin (5 g/day) were administered after her transfer, 7 days after admission emergency exploratory surgery was performed because of poor response to therapy. Bowel perforation was noted and a temporary colostomy was created without colectomy. Vancomycin (2.0 g/day) was administered via the colostomy, in addition to a vancomycin enema (2.0 g/day), oral metronidazole (1500 mg/day), and oral vancomycin (2.0 g/day). Three days after the operation, linezolid (1200 mg/day IV) was added. She was treated with antibiotics against C. difficile for a total of 18 days after the operation. The same strain was not isolated from other patients in the same ward. Microbiological analysis of the isolate revealed housekeeping gene (tpi), toxin A gene (tcdA), toxin B gene (tcdB), and binary toxin gene (cdtA and cdtB). DNA sequencing of tcdC revealed a base 117 deletion and contained an 18-bp tcdC deletion. PCR ribotyping showed ribotype 027 patterns. The MIC of moxifloxacin was >32 μg/ml, indicating resistance to fluoroquinolones. This isolate was considered as the epidemic strain. Our case of fulminant colitis is apparently the first case involving the epidemic strain ribotype 027 in Japan.

New options of antibiotic combination therapy for multidrug-resistant Pseudomonas aeruginosa

Several antibiotic combinations have demonstrated increased activity against multidrug-resistant Pseudomonas aeruginosa (MDRP) in vitro compared with a single antibiotic. The aim of this study was to investigate the activity against MDRP of some aminoglycosides in combination with monobactam, piperacillin (PIPC), and carbapenem. Clinical isolates of MDRP were collected between November 2010 and October 2012 from patients in Tokyo Medical University Hospital, Tokyo (1,015 beds). Our new method was designed to evaluate three concentrations around the breakpoint of each drug using the Checkerboard method. The aminoglycosides tested were amikacin (AMK), tobramycin (TOB), and arbekacin (ABK). Ciprofloxacin, PIPC, and biapenem (BIPM), which have been reported to demonstrate combination effects, were also tested. Sixty-six MDRP strains were identified from the 2,417 P. aeruginosa strains. Of the 66, 27 tested positive for metallo-β-lactamase (MBL). Aztreonam (AZT) with AMK or ABK was the most effective against MDRP. PIPC with AMK or ABK were somewhat effective. AZT with AMK or ABK were more effective against MBL-positive strains than MBL-negative strains. However, PIPC with AMK or ABK were more effective against MBL-negative strains than MBL-positive strains. Combination activities showed differences between MBL-positive and MBL-negative strains.

Evolution and Single-Nucleotide Polymorphisms in Methicillin-Resistant Staphylococcus aureus Strains with Reduced Susceptibility to Vancomycin and Daptomycin, Based on Determination of the Complete Genome

ABSTRACT We obtained a series of methicillin-resistant Staphylococcus aureus isolates, including both daptomycin-susceptible strain TD1 and daptomycin-resistant strain TD4, from a patient. We determined the complete genome sequences of TD1 and TD4 using next-generation sequencing, and only four single-nucleotide polymorphisms (SNPs) were identified, one each in capB (E58K), rpoB (H481Y), lytN (I16V), and mprF (V351E). We determined that these four SNPs were sufficient to cause the strains to develop daptomycin, vancomycin, and rifampin resistance.

First case report of vancomycin-intermediate sequence type 72 Staphylococcus aureus with nonsusceptibility to daptomycin

BackgroundSequence type 72 methicillin-resistant Staphylococcus aureus (MRSA) SCCmec type IV (ST72-MRSA-IV) is the most common community-acquired MRSA clone in Korea. Resistance to daptomycin or vancomycin among community-acquired MRSA clones is not well described in the literature. We herein report the first case of vancomycin-intermediate, daptomycin-nonsusceptible ST72-MRSA-IV.Case presentationA 45-year-old Japanese man underwent aortic arch prosthesis implantation for treatment of a dissecting aortic aneurysm. Fourteen months later, he developed a prosthetic graft infection of the aortic arch and an anterior mediastinal abscess caused by ST72-MRSA-IV. First-line treatment with vancomycin and rifampicin failed, and daptomycin was thus administered. After several days, the treatment was changed to linezolid because of the re-emergence of fever. The patient’s condition resolved and no recurrence or other problems were seen for 1 year post-treatment. The infectious agent was definitively identified as vancomycin-intermediate, daptomycin-nonsusceptible, rifampicin-resistant ST72-MRSA-IV based on culture results and minimum inhibitory concentration testing.ConclusionThis case report illustrates the importance of fully understanding the changing epidemiology of infectious agents and the risk factors for the development of antibiotic resistance. Such information will help to minimize the emergence and spread of antibiotic-resistant strains. This report concerns one particular bacterial strain; however, the basic concepts involved in this case translate to all infectious disease fields.

First case report of infection due to Cupriavidus gilardii in a patient without immunodeficiency: a case report

BackgroundCupriavidus gilardii is an aerobic, Gram-negative, glucose-nonfermenting rod that was first identified in 1999. Because of the difficulty in accurate species identification of C. gilardii, there are few case reports of infection caused by this organism. In previous reports, C. gilardii has been characterized as an organism with low pathogenicity that causes opportunistic infections.Case presentationWe encountered a case of pacemaker-associated bloodstream infection caused by C. gilardii in a 90-year old woman without obvious immunodeficiency. We identified the isolates as C. gilardii by sequencing of the 16S rRNA gene. The patient was treated with removal of the lead and administration of antimicrobial agents. Because of the acquisition of antibiotic resistance during antibiotic treatment, the antimicrobial agent was changed during the course of treatment.ConclusionsTo our knowledge, this is the first report of an infection caused by this organism in a patient without obvious immunodeficiency. Although the true pathogenicity of C. gilardii is unclear, the possibility that it exerts pathogenicity not only in persons with immunodeficiency but also in immunocompetent persons is suggested.

Severe infective endocarditis in a healthy adult due to Streptococcus agalactiae.

A case of severe endocarditis, with complications of multiple infarction, meningitis, and ruptured mitral chordae tendineae, caused by Streptococcus agalactiae in a healthy man, is reported. Emergency cardiovascular surgery was performed on the day of admission. Infective endocarditis caused by S. agalactiae is very rare, particularly in a healthy adult. In addition, microbiological analysis revealed that S. agalactiae of sequence type (ST) 19, which belongs to serotype III, was present in the patients vegetation, mitral valve, and blood culture. It was therefore concluded that the endocarditis was caused by ST19, which has been reported as a non-invasive type of S. agalactiae. This was an extremely rare case in which S. agalactiae of ST19 caused very severe endocarditis in an adult patient with no underlying disease.

Scenario-based simulation health care education for performance of hand hygiene

Background: Simulation health care education is widely used in medical education and has great potential. However, scenario‐based simulation health care education for preventing health care‐associated infections has not been described. Methods: A single‐center, prospective cohort study was conducted at Tokyo Medical University Hospital (1,015 beds), an acute care teaching hospital, from January 2011 to December 2014. Each training course was held every month and lasted 2 hours. Trainees put on and removed personal protective equipment under scenarios of standard precaution (2 scenarios) and contact precaution with methicillin‐resistant Staphylococcus aureus (1 scenario), while considering the timing of hand hygiene. We determined the correlations between the participation rate in the simulation education and the use of alcohol‐based hand disinfection and reduction of catheter‐related bloodstream infection. Results: There were 1,077 trainees. The total participation rate for hospital staff, which increased gradually during the study period, was 76% by the end of the study. The overall correlation between the use of alcohol‐based hand disinfection in the hospital and the course participation rate was significant (correlation coefficient, 0.97). An inverse correlation (−0.94) was observed for the relation between the training course participation rate and the incidence of catheter‐related bloodstream infection. Conclusions: Our training course had a positive effect on hand hygiene. This study is the first effective scenario‐based simulation health care education on hand hygiene and control of health care‐associated infection.

Solitary pulmonary caseating granulomas: A 5‑year retrospective single‑center analysis

Solitary pulmonary caseating granulomas (SPCGs) are a characteristic type of tuberculomas associated with infection with non-tuberculous mycobacteria (NTM) and other microbes; however, their significance remains unclear. The aim of the present study was to describe the clinical characteristics of patients with SPCGs in terms of diagnosis, presence of lung cancer and treatment status. A retrospective analysis of 17 immunocompetent patients with histopathologically confirmed caseating granulomas after undergoing video-assisted thoracoscopic surgery (VATS) was conducted at our center between 2011 and 2015. The patients comprised 10 men and 7 women with a mean age of 59.1±14.4 years. Of the 17 patients, 14 (82.4%) were asymptomatic and the lesions were discovered incidentally. In 2 patients the SPCGs were accompanied by a small satellite nodule (SPCG mean diameter, 16.2±5.1 mm). Mycobacteria, including Mycobacterium tuberculosis (11.8%), Mycobacterium avium (11.8%) Mycobacterium kansasii (23.5%) and other Mycobacterium spp. (5.9%), were isolated from 9 of the patients (52.9%). Concurrent lung cancer was present in 3 patients (17.6%). When microbial agents could not be isolated, the interferon-γ release assay was useful for diagnosis. Positron emission tomography was not found to be useful for differentiating SPCGs from lung cancer, or for differentiating tuberculomas from NTM pulmonary nodules (NTMPNs). NTMPNs in cases of SPCGs were diagnosed more frequently in men. The findings indicate that a course of observation may be sufficient for patients in whom an SPCG from NTM (NTMPN) is identified by VATS. However, the presence of concurrent lung cancer in certain cases indicates that malignancy should not necessarily be excluded, particularly in NTMPNs, and highlights the necessity of aggressive diagnosis by VATS.