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Summary: The antibacterial potential of honey has been of great scientific interest. Understanding the underlying mechanism is essential to explore its potential as therapeutic alternative against a range of (non)pathogenic microorganisms. The floral origin of honey is critical for its antibacterial activity and Greek thyme honeys have been of increasing interest due to their chemical composition and bioactivity. In this study, the antimicrobial effect of six Greek honeys, with different percentages of thyme pollen grains and two Manuka honeys were tested against four MRSA clinical isolates (ATCC 43300, 0791, 28965, 01322). Agar‐well diffusion assay and total viable counts were used to examine the antimicrobial strength of honeys, while the effect thereof on cellular redox state and cell membrane was tested by flow cytometry. Thyme honeys had superior or equal antimicrobial strength compared to this of Manuka, while thermal processing did not significantly affect this activity. Acidity and the high H2O2 content, common features for all thyme honeys, caused cellular oxidative damage and cell death unlike observed in Manuka‐treated populations. The activity of the monofloral thyme honey (74% thyme pollen) was higher than the other indigenous polyfloral samples, which confirms the medicinal importance of this medicinal plant. [ABSTRACT FROM AUTHOR]

Colonization of methicillin resistant Staphylococccus aureus ( MRSA) can occur more commonly in healthy people who live in close together or are in close physical contact with each other. Having knowledge about the molecular characteristics of these strains provides considerable discernment into the epidemiology of this important microorganism. A total of 806 nasal swabs were collected from healthy workers of an automaker company in the southeast of Iran and were analyzed to detect MRSA isolates. Multilocus sequence typing ( MLST), spa typing, and detection of staphylococcal cassette chromosome mec ( SCC mec) were performed. The presence of genes encoding Panton-Valentine Leukocidin ( PVL) and Arginine Catabolic Mobile Element ( ACME) were also investigated. Carriage rate of S. aureus was 20%. Among 10 identified MRSA, no acme was found while high prevalence of pvl (60%) was of great concern. Seven different spa types including five new ones were identified. The most frequent sequence type was the novel one; ST 3373 (n = 3), followed by each of ST22, ST88, ST859 (n = 2) and ST1955 (n = 1). MRSA isolates were clustered into two main clonal complexes; CC22 (n = 6) and CC88 (n = 4). Low genetic diversity with the dominance of CC22, SCC mec IV was found. Distribution of previously found hospital-associated MRSA was demonstrated among our isolates. [ABSTRACT FROM AUTHOR]

Objectives: To determine the prevalence, antimicrobial susceptibility profiles and clonal distribution of either methicillin-resistant Staphylococcus aureus (MRSA) or Panton-Valentine leukocidin (PVL)-positive S. aureus obtained from clinical cultures in Indonesian hospitals.Methods: S. aureus isolates from clinical cultures of patients in four tertiary care hospitals in Denpasar, Malang, Padang and Semarang were included. We assessed the antimicrobial susceptibility profiles using the Vitek2(®) system, determined the presence of the mecA gene and genes encoding PVL using PCR and analysed the clonal relatedness with Raman spectroscopy. SCCmec typing was performed for all MRSA isolates. Multilocus sequence typing (MLST) was performed for a subset of isolates.Results: In total, 259 S. aureus strains were collected. Of these, 17/259 (6.6%) and 48/259 (18.5%) were MRSA and PVL-positive methicillin-susceptible S. aureus (MSSA), respectively. The prevalence of MRSA and PVL-positive MSSA ranged between 2.5-8.9% and 9.5-29.1%, respectively and depended on geographic origin. PVL-positive MRSA were not detected. Raman spectroscopy of the strains revealed multiple Raman types with two predominant clusters. We also showed possible transmission of a ST239-MRSA-SCCmec type III strain and a ST121 PVL-positive MSSA in one of the hospitals.Conclusions: We showed that MRSA and PVL-positive MSSA are of clinical importance in Indonesian hospitals. A national surveillance system should be set-up to further monitor this. To reduce the prevalence of MRSA in Indonesian hospitals, a bundle of intervention measures is highly recommended. [ABSTRACT FROM AUTHOR]

From the oligotrophic culture of a soft coral-associated actinomycetes strain, Streptomyces sp. OUCMDZ-1703, we isolated and identified two new chlorinated polyketides that we named strepchloritides A and B ( 1 and 2), three thiazole derivatives known as watasemycin A ( 3), pulicatin G ( 4) and aerugine ( 5), along with pyrrole-2-carboxamide, furan-2-carboxamide and 1-(3,5-dihydroxyphenyl)ethanone. The new structures of 1 and 2 were determined by spectroscopic studies such as 1D- and 2D-NMR and MS analyses, while the known compounds were identified by comparison of the NMR data with those in literatures. The results showed that actinomycete strain OUCMDZ-1703 could use the relative high ratio of chlorine in the oligotrophic medium to synthesize chlorinated natural products. New compounds 1 and 2 displayed cytotoxicity against the MCF-7 cells with IC50 values of 9.9 and 20.2 µmol·L−1, respectively. Thiazole derivatives 3 and 5 were first found to be active against three clinical strains of methicillin-resistant Staphylococcus aureus (MRSA082, MRSA111 and MRSA234) with the same MIC/MBC values of 7.81/7.81 µg·mL−1. [ABSTRACT FROM AUTHOR]

Objective: To examine the causative organisms in pediatric neck infections, delineate risk factors in methicillin-resistant Staphylococcus aureus (MRSA) pediatric neck infections, and define patient populations that should be empirically treated with MRSA sensitive antibiotics. Study Design: Retrospective chart review. Methods: Two hundred twenty-eight consecutive patients were reviewed, ages 0 to 17, presenting at a tertiary care center between 1999 and 2007 with computed tomography proven neck abscesses. Characteristics of patients with differing causative organisms were compared. Results: Forty-eight percent of all pediatric patients' with head and neck abscesses had S. aureus as the causative organism, 29% of which were community-acquired MRSA-recent years showed that up to 66% of pediatric neck abscesses were MRSA culture positive. When comparing MRSA infections vs. other causative organisms multiple clinical characteristics were found which did not help to differentiate those patients at a higher risk for MRSA. Characteristics which did trend to predict an MRSA infection were few. For example, the average age of patients with MRSA was 32.5 months compared with only 16 months for the methicillin-sensitive S. aureus patients. MRSA sensitivities and resistances were also examined. Conclusions: This study presents a large cohort of pediatric neck abscess patients, in which the emergence and characteristics of MRSA are shown. As community-acquired MRSA infections become more prevalent, empiric antibiotic therapy must be considered. The results of this study show that the incidence of MRSA has greatly increased and clinical risk factors are not helpful in choosing those patients which may be at higher risk for an MRSA infection. [ABSTRACT FROM AUTHOR]

Methicillin-resistant S. aureus has been reported as the main pathogen involved in chronic infections, osteomyelitis, and prosthetic joint infections. The host/pathogen interaction is dynamic and requires several changes to promote bacterial survival. Here, we focused on the internalization and persistence behavior of well-characterized Staphylococcus aureus invasive strains belonging to the main ST-MRSA-SCCmec clones. To overcome the limitations of the cell culture method, we comparatively analyzed the ability of internalization within human MG-63 osteoblasts with imaging flow cytometry (IFC). After evaluation by cell culture assay, the MRSA clones in the study were all able to readily internalize at 3h postinfection, the persistence of intracellular bacteria was evaluated at 24h both by routine cell culture and IFC assay, after vancomycin-BODIPY staining. A statistical difference of persistence was found in ST5-SCCmecII (26.59%), ST228-SCCmecI (20.25%), ST8-SCCmecIV (19.52%), ST239-SCCmecIII (47.82%), and ST22-SCCmecIVh (50.55%) showing the same ability to internalize as ATCC12598 (51%), the invasive isolate used as control strain for invasion and persistence assays. We demonstrated that the intracellular persistence process depends on the total number of infected cells. Comparing our data obtained by IFC with those of the cell culture assay, we obtained greater reproducibility rates and a number of intracellular bacteria, with the advantage of analyzing live host cells. Moreover, with some limitations related to the lack of whole-genome sequencing analysis, we validated the different proclivities to persist in the main Italian HA-MRSA invasive isolates and our results highlighted the heterogeneity of the different clones to persist during cell infection., (© 2020 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

The aims of this study were to determine the antimicrobial susceptibility profile and genetic diversity of Staphylococcus spp. isolated from dairy cows in Minas Gerais, Brazil, and to assess the relationship among the isolates' susceptibility profiles and pulsed-field gel electrophoresis (PFGE) genotypes. Seventy-nine isolates were used, including S. aureus (n = 71) and coagulase-negative staphylococci (CoNS) (n = 8). Susceptibility to 12 antimicrobial agents was performed. All Staphylococcus spp. were subjected to PFGE. Staphylococcus aureus and CoNS isolates exhibited full susceptibility only to cephalothin. The greatest percentages of resistance among Staphylococcus spp. were observed to penicillins, folate pathway inhibitors, and tetracyclines. Twelve S. aureus and four CoNS were classified as multidrug resistance strains. Percentage of MRSA was also higher among CoNS (75%), compared to S. aureus isolates (2.81%). Adopting 100% of similarity, 34 different genotypes were identified. Association of minimum-spanning tree (MST) analysis with data from municipalities, herds, methicillin-resistant S. aureus (MRSA), and resistance patterns for all isolates did not show any clustering. However, a clustering pattern of bacterial species was observed. Results from this study indicate a high frequency of antimicrobial resistance, especially among CoNS, and a high genetic diversity among Staphylococcus spp. isolated from dairy cows with mastitis in Minas Gerais, Brazil., (© 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)