In staphylococci, methicillin (meticillin) resistance (MR) is mediated by the acquisition of the

Approximately one-third of the human population is asymptomatically colonized by Staphylococcus aureus. However, much of the global diversity within the carriage populations remains uncharacterized, and it is unclear to what degree the variation is geographically partitioned. We isolated 300 carriage isolates from 1,531 adults contemporaneously in four countries: France, Algeria, Moldova, and Cambodia. All strains were characterized by multilocus sequence typing. Six clonal complexes (CCs) were present in all four samples (CC30, -45, -121, -15, -5, and -8). Analyses based on the genotype frequencies revealed the French and Algerian samples to be most similar and the Cambodian sample to be most distinct. While this pattern is consistent with likely rates of human migration and geographic distance, stochastic clonal expansion also contributes to regional differences. Phylogenetic analysis revealed a highly divergent and uncharacterized genotype (ST1223) within Cambodia. This lineage is related to CC75, which has previously been observed only in remote aboriginal populations in northern Australia.

Introduction: The objective of this study was to evaluate the antibacterial activity of hydromethanolic extracts of Berberis vulgaris, Cassia angustifolia, Cinnamomum cassia, Cistus monspeliensis, Nigella sativa, Punica granatum, Rhus tripartata, Withania frutescens and Zingiber officinale against different Gram-positive and Gram-negative reference bacterial strains. Methods: The evaluation of antibacterial activity for different extracts of each plant was carried out using the disc diffusion method and determination of minimum inhibitory concentration (MIC). Results: The plant extracts showed zone of inhibition ranging from 06.0 to 23.0 mm against one or more tested bacteria, and their efficacy in terms of MICs where ranged from 0.1 to 12.8 mg/mL. The Refluxed and Macerated extracts of these plants have shown relatively similar results in terms of diameters of inhibition and MICs. The extracts of B. vulgaris, C. monspeliensis and P. granatum demonstrated relatively high activity as compared to the other plant extracts mainly against S. aureus, E. faecalis and E. cloacae. Conclusion: Findings of this study indicate that hydromethanolic extracts of these plants have antibacterial activity against the different tested bacterial strains. This activity supports their use in treatment of infections caused by such resistant bacteria.

The burden of disease caused by Staphylococcus aureus continues to grow; this organism has the ability to form biofilm and it is also a frequent cause of medical device and implant-related infections. The objective of this study was to evaluate the biofilm-forming ability of a collection of clinical isolates of S. aureus. In a total of 240 Staphylococcus spp. isolated from catheters, retrieved at five services (neonatology, internal medicine, pneumology, pediatric and neurology), only 50 (20.83%) strains were identified by conventional microbiological methods as S. aureus species; these strains were screened by microtiter plate assay for detection of biofilm formation. Of the 50 clinical isolates, 16 (32%) were non adherent, 20(40%) weakly, 10 (20%) moderately and 4(8%) strongly adherent. The quantitative method of microtiter plate can be involved as a simple, rapid, inexpensive and reproducible assay to assess biofilm formation which is further an important feature of pathogenecity of S. aureus in the clinical setting.

Isolates of Klebsiella pneumoniae are responsible for opportunistic infections in humans, particularly of the urinary respiratory tracts. These bacteria express type 3 fimbriae that have been implicated in binding to eukaryotic cells and matrix proteins. Twenty four (24) K. pneumoniae strains isolated from medical devices were studied. Their capacity to form biofilm was assessed using two types of materials, polyvinylchloride (PVC) and glass of microfermenter in static or kinetic conditions. Strains with adherence to PVC also cling strongly to glass slides. We determined the in vitro effects of three antimicrobial agents against planktonic and biofilm forms of K. pneumoniae and we demonstrated that isolates of the biofilm form were at least 10-25 times more resistant than the planktonic form. Most strains of K. pneumoniae harbored the mrkD gene and exhibited a strong ability to adhere to inert surfaces.