Although an exfoliative toxin (ET) or Panton-Valentine Leukocidin (PVL) may play a critical role in the pathogenesis of methicillin-resistant Staphylococcus aureus (MRSA) infection, little is known about genetic diversity among MRSA isolates producing ET or PVL. In this study, we investigated the PCR-based open reading frame typing (POT) along with toxin type and drug susceptibility in 40 strains of ET or PVL-producing MRSA isolated at Ehime University Hospital from January 2010 to December 2017.
Since all 22 ET-A and 10 ET-B producing strains showed 70-18-81 and 73-152-80, respectively, ET producing strains could be the same clones. A drug susceptibility test revealed that the ET-A strain and the ET-B strain showed the same pattern of 80% and 100%, respectively. Three kinds of PVL-producing strains were shown as follows, 106-77-113 (5 strains), 64-88-19 (2 strains), and 110-16-49 (1 strain). Thus it was likely that they were multiple clones.
The POT typing is useful to detect ET producing strains because they could be the same clone in the POT typing. Although multiple clones were detected in the PVL strain, the strains with 106-77-113 and POT1 type of 64, 110 might be PVL producing strains. Since the classification of POT correlates with ET and PVL toxin production, it could be an effective method to identify toxin strains.

Hand washing and gargling are recommended for prevention of infectious diseases, especially in the case of epidemics. Currently, several disinfectant-containing hand-washing products and mouthwashes for general household use are available in the market. In this study, we compared the bactericidal or virusinactivating effects of these products. The pathogenic bacteria used for this study were MRSA and EHEC O 157, and the viruses were influenza A and feline calicivirus, used as a substitute for norovirus. The test solutions of various products were mixed with the pathogenic fluid at 9：1 or 5：5 and allowed to react for 15 seconds. The decrease in viable count and infectious virus titer after the reaction were measured with the dilution plate method and plaque method, respectively.
Products containing povidone-iodine or acidic ethanol showed a high reduction value (exceeding 4 log₁₀) against the bacteria and viruses tested. However, hypochlorous acid products and ordinary ethanol products for disinfection had little effect on feline calicivirus in this test method. A strong bactericidal or virusinactivating effect was confirmed when the test method was changed, with the mixing ratio at the time of reaction set to 9：1 and the coexisting cell culture medium components eliminated. These results suggested that the efficacies varied greatly depending on the test method. Products having reliable disinfection effects under the conditions in which they were used were considered useful for prevention of infectious diseases.

Nosocomial legionellosis has been reported to be associated with Legionella colonization of hospital water supply systems. Legionella colonization of the water supply system should be investigated to prevent the infection. This study aimed to determine the level of Legionella colonization in water supply systems in three hospitals in Kanagawa, Japan with Legionella DNA detection and culture methods. Water samples were collected from taps and showers, and swab samples were collected by swabbing the inside of taps and showerheads. Legionella culture was positive in 26.7%, 37.5% and 66.7% of the water samples, and in 0%, 14.3% and 7.7% of the swab samples from water supply systems of the three hospitals, respectively. Legionella DNA was found in 6.7%, 93.8% and 60.0% of the water samples, and in 0%, 7.1%, and 0% of the swab samples, respectively. Legionella pneumophila SG1, SG5, and SG6, Legionella feeleii SG1, and Legionella sp. L-29 were isolated from the water supply systems. Among the parameters analyzed, residual chlorine concentrations showed an inverse relationship with Legionella colonization in the water supply system according to a multivariate logistic regression analysis. This study suggests that hospital water supply systems are highly contaminated with Legionella spp. Control measures for preventing Legionella colonization should be implemented in hospital water supply systems.

Community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), which is genetically different from hospital-acquired MRSA, has been recognized as a novel pathogen. CA-MRSA usually induced skin or soft tissue infection. The prognosis of CA-MRSA infections would appear to be better than that of hospital acquired (HA)-MRSA infections. Recently the infective endocarditis caused by CA-MRSA has been reported, but these cases were rare in Japan.
A woman in her 40s was admitted to another hospital because of fever and mild disturbance of consciousness. Cardiac echography was conducted to detect the focus of the fever, and vegetation was found at the mitral valve. She was transferred to our hospital to undergo further treatment including a surgical approach. Transesophageal echocardiography detected vegetation at the anterior leaflet of the mitral valve. Brain magnetic response imaging (MRI) showed multiple small infarctions. MRSA was detected several times from blood cultures. The staphylococcal cassette chromosome mec analysis of MRSA showed type IV,revealing that MRSA in this case was CA-MRSA. The patient was then diagnosed as having infective endocarditis (IE) with multiple cardioembolic cerebellar infarction caused by CA-MRSA. Further study found the disseminated lesions, such as pyogenic spondylitis, intramuclar and skin abcesses. At the same time, untreated diabetes mellitus was found and insulin therapy was started immediately. She was treated successfully with the administration of several antibiotics, the surgical removal of the vegetation and a mitral valve plasty. CA-MRSA is an emerging pathogen and has the capability to be one of the causes of IE.

We report herein on a 61-year-old Japanese man with severe falciparum malaria after visiting African countries. He presented with shock, impaired consciousness, acidosis, renal impairment, jaundice, pulmonary edema and hyperparasitemia (42.7%). We admitted him to our intensive-care unit. He was initially treated with intravenous quinine (4,500mg for 3 days), rectal artesunate (1,200mg for 5days) and aggressive supportive therapy. The sequential treatment was mefloquine on day 7 (1,925mg). The 99% parasite clearance time and ICU stay were 92 hours and 8days, respectively. He was discharged without complications on the 28th day. Severe malaria, especially cerebral malaria, is a highly mortal disease requiring urgent treatment. Intravenous artesunate is now recommended as the treatment of choice for severe malaria by the World Health Organization, but it is unavilable in Japan. We found that our combination treatment had excellent antimalarial activity with rapid efficacy, and was safe and well-tolerated.

In patients with human immunodeficiency virus (HIV) infection, toxoplasmic encephalitis (TE) is a common cause of space-occupying brain lesions, but primary central nervous system lymphoma (PCNSL) can likewise present as a focal brain lesion and has a poor prognosis. Therefore, distinguishing TE from PCNSL is important, but usually difficult. We herein on report a rare case for TE complicated with PCNSL in a patient with HIV infection. He was referred to our hospital with tonic-clonic seizures. He had been treated for TE and HIV infection for 5 years, but he stopped going to the hospital 2 years previously. His CD4-positive cell count was 2/μL and the serum anti-Toxoplasma IgG antibody was positive. Cranial magnetic resonance imaging (MRI) showed a 2.7-cm nodule with the eccentric target sign and surrounding edema in the right parietal lobe. Thallium-201 scintigraphy showed an uptake in the nodule. Both Epstein-Barr virus and Toxoplasma gondii DNAs were detected in the cerebrospinal fluid with the polymerase chain reaction (PCR) technique. Because empiric treatment for TE failed to improve his symptoms, a brain biopsy was performed and showed PCNSL on histopathologic examination and Toxoplasma DNA on PCR. After whole-brain radiation therapy, dexamethasone, and antiretroviral therapy, his symptoms and MRI abnormalities improved. A brain biopsy and Toxoplasma PCR test should be considered in cases with atypical clinical presentation.

Legionella pneumonia can rapidly progress, therefore early diagnosis and treatment are important. The urinary antigen test (UAT) is a simple, easy, and useful diagnostic tool that is widely used；however, the UAT can only detect Legionella pneumonia caused by Legionella pneumophila serogroup 1. Alternatively, loopmediated isothermal amplification (LAMP) of genetic material is a quick, simple,and accurate method to detect many species of the Legionella genus and its serotypes. Widespread use of LAMP is recommended. Herein, we describe a case of severe pneumonia caused by Legionella pneumophila serogroup 8 which demonstrates negative UAT results, but positive LAMP results.