The approach of combining different mechanisms of antibacterial action by designing hybrid nanomaterials provides a new paradigm in the fight against resistant bacteria. Here, we present a new method for the synthesis of silver nanoparticles enveloped in the biopolymer chitosan. The method aims at the production of bionanocomposites with enhanced antibacterial properties. We find that chitosan and silver nanoparticles act synergistically against two strains of Gram-positive Staphylococcus aureus (S. aureus). As a result the bionanocomposites exhibit higher antibacterial activity than any component acting alone. The minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations of the chitosan-silver nanoparticles synthesized at 0 °C were found to be lower than those reported for other types of silver nanoparticles. Atomic force microscopy (AFM) revealed dramatic changes in morphology of S. aureus cells due to disruption of bacterial cell wall integrity after incubation with chitosan-silver nanoparticles. Finally, we demonstrate that silver nanoparticles can be used not only as antibacterial agents but also as excellent plasmonic substrates to identify bacteria and monitor the induced biochemical changes in the bacterial cell wall via surface enhanced Raman scattering (SERS) spectroscopy.

The Blasius's horseshoe bat (Rhinolophus blasii) shows a fragmented distribution in the European part of its range, and its populations are threatened by many human-induced factors. The status and distribution of the species in Romania are largely unknown. In recent years, regular bat surveys and monitoring have confirmed the presence of the species in north-western Romania, in Gălăşeni Cave, Pădurea Craiului Mountains, representing the northernmost distribution point of R. blasii in Europe. In our study we investigated whether this northernmost colony is genetically isolated from, or related to, larger populations in south-western Romania. A combined analysis of two mitochondrial (12S, HVII) and two nuclear (RAG2, DBY7) genetic markers was used in order to reveal possible relationships between these populations. The small number of haplotypes, the presence of shared haplotypes and overall low population structure suggest that the south-western and north-western Romanian populations are related through yet unidentified colonies of R. blasii, with continuous migration between them. Our results also indicate that the R. blasii colony from Gălăşeni Cave was established by female individuals migrating not far from their birthplace. To preserve this marginal population in a long term, conservation measures need to be strengthened and properly enforced, in parallel with the search for new R. blasii colonies in the region. To our knowledge, the present work represents the only molecular study of R. blasii in Europe.

In the last few decades, methicillin-resistant Staphylococcus aureus (MRSA) strains have become a serious health care problem. However, in the European Union/European Economic Area countries the prevalence of the invasive MRSA isolates has decreased in recent years; in Romania, the considerably high prevalence of these strains is still unchanged. In this study, 396 staphylococcal strains were screened using molecular biology techniques for the presence of the nucA , mecA, and mecI genes and for the detection of the possible mutations accumulated in the mecI gene. More than half of the collected Staphylococcus strains (59.34%) were determined as S. aureus , and 63 strains were considered as MRSA. Small number of MRSA strains ( n = 6; 54.54% of invasive S. aureus ) originated from hemoculture. The mecI gene was present in 22 MRSA strains and in 4 methicillin-resistant coagulase-negative staphylococci strains. The majority of the mecI -positive MRSA strains contained the C to T substitution at position 202; furthermore, one previously undescribed mutation (C to G transversion at nucleotide position 285) was detected in one MRSA strain.

Enterococcus faecium is emerging as an important cause of multidrug resistance and hospital acquired infections, special attention being paid to the vancomycin resistant species. Therefore, the characterization of pathogenic strains/isolates plays an important role in the epidemiology of infectious diseases. The enterococcal rate was determined from wastewaters in Cluj-Napoca area. As presence of E. faecium was detected, a number of isolates from wastewater, birds and humans were epidemiologically analyzed according to the MLST website. Comparisons were performed against a collection of available isolates, with multiple origins, contained in the MLST database. Out of the Enterococcus isolates collected from wastewater, 11 were identified as E. faecalis (40.74%); 8 as E. casseliflavus (29.62%); 5 as E. faecium (18.50%); 2 as E. gallinarum (7.40%) and one isolate as E. durans. Based on the MLST data and using the eBURST algorithm, the isolates of E. faecium sampled from Romania were split in three groups: one group comprised isolates from human hosts and wastewater (Cj316, 106/6, Cj197, Cj22, 129/6, Cj117, Cj24, 284/7, and 43/7), while the second (G9, G10-2, G7, G3-2, and G9-1) and the third group (G8, G6, and 40/7) originated from bird hosts. The rest of the isolates were not joined in a particular group, assuming the lack of a phylogenetic bond between these isolates. The obtained data suggested the existence of at least two phylogenetic lines of E. faecium in Romania: a line that had mainly human host prevalence, while in the other line the animal hosts dominated.