Significant increase in the prevalence of Panton-Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus, particularly the USA300 variant ΨUSA300, in the Japanese community

IMPORTANCE

USA300 is an MRSA clone producing PVL, a toxin associated with SSTIs. ΨUSA300 is a USA300 variant recently identified in Japan by Takadama et al. (15). Here, we found that the prevalence rate of PVL-positive MRSA in S. aureus was elevated in the Japanese community, and ΨUSA300 accounted for most of them. ΨUSA300 strains have been isolated from several areas in Japan and were associated with deep-seated SSTIs. This study highlighted the emerging threat posed by ΨUSA300 in Japan.

Current status of Panton-Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus isolated from patients with skin and soft tissue infections in Japan

The USA300 clone, which produces Panton-Valentine leukocidin (PVL), is a major pathogenic community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clone that causes intractable skin infections. Recently, PVL-positive CA-MRSA, including USA300 clones, have emerged in both communities and hospitals in Japan. To prevent an outbreak of PVL-positive MRSA, infected patients should be treated with effective antimicrobial agents at community clinics. Herein, we investigate molecular epidemiological characteristics of PVL-positive MRSA isolated from outpatients with skin and soft tissue infections (SSTI), which are common community-onset infectious diseases. The detection rate of MRSA was 24.9% (362 strains) out of 1455 S. aureus strains isolated between 2013 and 2017. Among the MRSA strains, 15.5% (56 strains) were PVL-positive strains and associated with deep-seated skin infections. Molecular epidemiological analyses of PVL-positive MRSA showed that USA300 was the predominant clone (53.6%, 30 strains) and was identified in Kanto (18 strains), Kagawa (nine strains), Tohoku (two strains) and Hokkaido (one strain). Notably, minocycline and fusidic acid were effective against all PVL-positive MRSA strains. Hence, our data reveals the current status of PVL-positive MRSA isolated from patients with SSTI in Japan. Continuous surveillance of CA-MRSA is necessary to monitor latest prevalence rates and identify effective antimicrobial agents for PVL-positive MRSA strains.

Comparative analysis of methicillin-resistant Staphylococcus aureus isolated from outpatients of dermatology unit in hospitals and clinics

Community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) is a causative agent of intractable skin infections. In general, clinical symptoms of hospital outpatients with skin infections are severer than those of clinic patients. Hence, molecular epidemiological features of the CO-MRSA strains from hospital outpatients are predicted to be different from those of clinic patients. Here, we conducted a comparative analysis for CO-MRSA isolates from outpatients with impetigo in hospitals and clinics located in the same district of Tokyo, Japan. Incidence of MRSA infection was higher in hospital outpatients (21.5%, 20/93 isolates) than in clinic patients (14.5%, 121/845 isolates). The resistance rate to clindamycin, which is a common topical antimicrobial agent in dermatology, in the isolates from hospital outpatients (60.0%) was higher than those from clinic patients (31.4%). Proportion of the staphylococcal cassette chromosome (SCC) mec type II, which is a representative type of hospital-acquired MRSA in Japan, in the isolates from hospital outpatients (65.0%) was significantly higher than those from clinic patients (30.6%) (P < 0.01). Multilocus sequence typing showed that the clonal complex 89-SCCmec type II (CC89-II) clone, which exhibits clindamycin resistance, was the most predominant (55.0%) in the isolates from hospital outpatients. On the other hand, all CC8-IV, CC121-V, and CC89-V clones accounted for 60% in clinic patients were susceptible to clindamycin. Our findings suggested that the clindamycin-resistant CC89-II CO-MRSA clone might be more related to skin infections in hospital outpatients than clinic patients.

Shape and number of the roots of the permanent molar teeth

One hundred ninety-eight mandibular first molars, 198 mandibular second molars, and 122 mandibular third molars, extracted from 99 Indian skulls were examined for the number of dental roots. The number of mandibular molar roots is increased by the appearance of the distolingual root, accessory lingual root, and bifurcation of the mesial root. The bifurcation of the mesial root was investigated in teeth in which it was more than 1/3 and less than 1/3 (apical bifurcation) of the root length. The following results were obtained. The numbers of the roots including apical bifurcation of the mesial root were 2, 3 and 4 in 72.7%, 26.8% and 0.5%, respectively, of the first molars; 1, 2 and 3 in 17.7%, 76.8% and 5.6%, respectively, of the second molars; and 1, 2 and 3 in 16.4%, 77.1% and 5.8%, respectively, of the third molars. The numbers of dental roots excluding apical bifurcation of the mesial root were 2 and 3 in 99.0% and 1.0%, respectively, of the first molars; 1, 2 and 3 in 17.7%, 81.8% and 0.5%, respectively, of the second molars; and 1, 2 and 3 in 16.4%, 77.1% and 5.8%, respectively, of the third molars.

[A study involving early carcinomas of the gall bladder]

In recent years, with the development of diagnostic procedures, the number of cases of early carcinoma of the gall bladder has been seen to gradually increase. In this paper, 8 cases of early gall bladder carcinoma have been evaluated, using a diagnostic approach. Cholecystolithiasis was the complication in 6 cases, and abdominal pain was seen as the most common symptom. Findings by various image diagnoses, such as ultrasonography, DIC, ERCP, and CT scan are described and discussed with a review of literature. Ultrasonography was considered to be the most useful tool for the detection and diagnosis of an early carcinoma of the gall bladder. A survey is thought to be required, involving the cases that have accumulated throughout the entire nation.

[Sialylated Lewis x as a tumor-associated antigen in stomach cancer]

Sialylated Lewis (S-Lex) has been studied histologically and serologically in stomach cancer by the CSLEX1 monoclonal antibody. S-Lex was expressed in 73.9% of 46 stomach cancer tissues, 29.4% of metaplastic parts adjacent to cancer, and none of six gastric ulcer tissues including metaplasia. Serologically positive percentages were as follows: 26.0% of 100 stomach cancers, 0.9% of 322 benign diseases, and 0.7% of 280 healthy donors in the sera, as well as 72.4% of 29 ascites of stomach cancers and 5.3% of 17 effusions of benign diseases. These findings demonstrate that S-Lex possesses a potential usefulness as a tumor marker in stomach cancer.