[Comparison of PVL-producing MRSA Showing POT Type 106-77-113 and POT Type 106-255-121 Detected in Materials Derived from Patients with Skin Infections].

Methicillin-resistant Staphylococcus aureus (MRSA) strains showing POT type 106-77-113 have been associated with USA300. Additionally, many strains produce Panton-Valentine Leukocidin (PVL). Until 2018, 106-77-113 was the most dominant POT-type PVL-producing bacteria isolated in our hospital; however, in 2018, one strain with POT type 106-255-121 was isolated, and thereafter, since 2019, an increasing trend towards isolation of this strain has been observed. In this study, we compared two PVL-producing strains detected in skin infections-derived materials from outpatients during the three-year period between 2019 and 2021 through genetic analysis using next-generation sequencers. Eight, each of POT types 106-77-113 (POT-A) and 106-255-121 (POT-B), strains were included in this study, and PVL productivity, drug susceptibility, multi-locus sequencing typing (MLST), and resistance genes and virulence genes were detected. Both the groups shared the same MLST profile (3-3-1-1-4-4-3), but a single nucleotide mutation of ARCC was detected in POT-B type strain, which was determined to be similar to ST 8 of POT-A and POT-B type strains. Only POT-B type strains harbored aac(6')-aph(2″) and erm(A) genes, consistent with the results of drug susceptibility tests. All the strains were resistant to GM and CAM and were positive to D-zone test. On the other hand, the POT-A strains were sensitive to GM, and 7 of 8 strains were sensitive to CLDM and MINO. However, one POT-A type strain was found to harbor erm(C), tet(K), and tet(M) genes and was resistant to CAM, CLDM, and MINO. Both groups of isolates harbored 17 genes including ACME, lukF-PV, and LukS-PV, and no difference in pathogenicity was observed. In our hospital, one strain of POT type 106-255-121 was isolated for the first time in 2018, and the number of isolates of this type has been increasing since then. The present study confirms that POT type 106-255-121 strains have the same virulence as POT type 106-77-113 strains have and have also acquired a drug resistance gene.

Incidence and Antimicrobial Susceptibilities of Mycoplasma hominis in Pregnant Females, Ehime University Hospital.

OBJECTIVE: Mycoplasma hominis usually colonizes the lower urogenital tract and has been occasionally associated with pelvic inflammatory disease, postpartum fever, preterm labor in pregnant females. The aim of this study was to investigate the incidence and antimicrobial susceptibilities of M. hominis isolated from the urogenital tracts of pregnant females. METHODS: Specimens were obtained from the urogenital tract of pregnant females at Department of Obstetrics and Gynecology, Ehime University Hospital, between November 2014 and December 2017. The identification of M. hominis was confirmed by the polymerase chain reaction (PCR) methods. The minimum inhibitory concentrations (MICs) of antibiotics were measured using a broth microdilution assay. RESULTS: Of the 1074 specimens tested, 63 (5.9%) were positive for M. hominis. The M. hominis-positive rate was highest at 21.3% between 18 and 24 years old. The 21 (25.6%) of 82 patients with bacterial vaginosis were positive for M. hominis. The 17 (40.5%) of 42 patients delivered by cesarean section that occurred infections including of intrauterine infection and pelvic abscess were positive for M. hominis. They were all administered ß-lactam antibiotics before and after cesarean section. All patients recovered immediately following administration of clindamycin (CLDM). ß-lactam antibiotics, macrolides and fosfomycin (FOM) were all resistant against M. hominis strains. In contrast, M. hominis strains were susceptible to CLDM, minocycline (MINO) and quinolones. CONCLUSIONS: Our data suggests that the prevalence of genital M. hominis in pregnant females is high at younger age, bacterial vaginosis and infections after cesarean section with ß-lactam antibiotics administration. CLDM, MINO and quinolones may be recommended against M. hominis infection. Especially, CLDM can be used as the adequate agent for pregnant females because tetracycline and quinolones are undesirable during pregnancy and lactation.

[Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus (MRSA) by POT Method, Antimicrobial Susceptibility Patterns, and Toxin-Producing Types].

The PCR-based open reading frame typing (POT) is an important method for analyzing outbreak information. Many institutions use POT as a molecular epidemiological method for analyzing horizontal transmission in methicillin-resistant Staphylococcus aureus (MRSA). However, typing and analyzing MRSA only based on POT, with high detection frequency, has some limitations. In this study, we analyzed 62 strains of MRSA, isolated at Ehime University Hospital between January 2018 to December 2018 based on six POT types, toxin type, and antimicrobial susceptibility. Types of POT and strains used were as follows: 106-183-37 (28 strains), 106-137-80 (7 strains), 106-77-113 (7 strains), 106-9-80 (7 strains), 70-18-81 (7 strains), 106-247-33 (6 strains). Based on antimicrobial susceptibility patterns, 5 types of MRSA were detected, including types susceptible to gentamicin (GM), clarithromycin (CAM), and levofloxacin (LVFX). Strains belonging to the same POT type, showed differential antimicrobial susceptibility patterns and had different toxin productivity. These findings suggest that the combination of POT method with antimicrobial susceptibility patterns and toxin type may be a useful technique for MRSA typing.