For a long time, Staphylococcus epidermidis, as a member of the coagulase-negative staphylococci, was considered as part of the physiological skin flora of the human being with no pathogenic significance. Today, we know that S. epidermidis is one of the most prevalent causes for implant-associated and nosocomial infections. We performed pheno- and genotypic analysis (ica, IS256, SCCmec types, agr groups) of biofilm formation in 200 isolates. Fifty percent were genetically ica-positive and produced biofilm. Among all studied isolates, agr II and III and SCCmec type I were the most prevalent, whereas within the selected multi-resistant isolates (29%), agr I and III and SCCmec type II dominated. SCCmec type I and mecA-negative S. epidermidis isolates were associated with agr II. The majority of the blood culture and biopsy isolates were assigned to agr III and SCCmec type I, whereas agr II was predominantly detected in mecA-negative S. epidermidis isolated from catheter and implant materials. MLST analysis revealed the major clonal lineages of ST2, ST5, ST10, and ST242 (total 13 STs). ST2 isolates from blood cultures were icaA/D-positive and harbored SCCmec types II and III and IS256, whereas the icaA/D- and IS256-positive ST23 isolates were assigned to SCCmec types I and IV.
Authors:Alexandra Sashova Alexandrova, Lena Petrova Setchanova, Daniela Rosenova Pencheva and Ivan Gergov Mitov
percent of MDR strains was distinctive for 6C isolates (56%), followed by 6A (28%) and 6B (16%). PCR – Analysis of macrolide resistance genes from serogroup 6 S. pneumoniae isolates The predominant geneticdeterminant for macrolide resistance out of all
Authors:Carlos Florindo, Cinthia Alves Barroco, Inês Silvestre, Vera Damião, João Paulo Gomes, Barbara Spellerberg, Ilda Santos-Sanches and Maria José Borrego
infections were not available, precluding any statistical evaluation of clinical findings for DNase production.
Sub-Characterization of CC19 Strains
For further phenotypic characterization and to identify putative geneticdeterminants associated with
Authors:Márta Balogh, Krisztina Miró, Ágnes Dalmadi, Gábor Deák, Tünde Petrovics, Brigitta Dudás, Péter Kiss, Júlia Jakab and György Kiss
A monogenic recessive
resistance determinant was identified in a diploid
susceptible and resistant phenotypes of the individuals in an F2 segregation population was inferred from a biological test using injured root test. The resulting phenotypes were used to position the
resistance determinant on linkage group 6 of the
genetic map. Using the DNA based molecular markers genome walk was initiated from both sides of the genetic region constructing two contigs which are about 0.5 centiMorgan (∼500 kilobasepairs) apart. The introduction of this genetic determinant into tetraploid alfalfa cultivars was unsuccessful since only triploid and pentaploid hybrids could be recovered from the 4×-2× crosses. The isolation of the gene and establishment of the function of this recessive
determinant is under progress.
In this study, the phage adsorption inhibition type resistance system was investigated in 6 bacteriocin producing strains,
BLL10, BLL27, BLL31, BLL84 and BLL90 and
BLC67. All six bacteriocin producing strains were determined to comprise phage adsorption inhibition type of resistance against three phages (Øpll98-28, Øpld67-41 and Øpld67-43). Genetic determinants of these two systems were also analysed in these strains. The bacteriocin production abilities and phage adsorption inhibition type resistance of these strains were found to be determined by 13.4 kb and 25.3 kb plasmids in BLL10; 9.5 kb and 30.1 kb plasmids in BLL27; 10.4 kb and 29.0 kb plasmids in BLL31; 23.4 kb and 19.0 kb plasmids in BLL84; 7.5 kb and 15.3 kb plasmids in BLL90, respectively. In BLC67, both characteristics were found to be determined by 31.3 kb plasmid. Conjugal mating experiments showed that 30.1 kb plasmid in BLL27, 29.0 kb plasmid in BLL31, 23.4 kb plasmid in BLL84 and 31.3 kb plasmid in BLC67 were conjugally transferable with the frequencies of 3.6×10
In certain conditions Campylobacter jejuni cells are capable of changing their cell shape from a typically spiral to a coccoid form (CF). By similarity to other bacteria, the latter was initially considered to be a viable but non-culturable form capable of survival in unfavourable conditions. However, subsequent studies with C. jejuni and closely related bacteria Helicobacter pylori suggested that CF represents a non-viable, degenerative form. Until now, the issue on whether the CF of C. jejuni is viable and infective is highly controversial. Despite some preliminary experiments on characterization of CF cells, neither biochemical mechanisms nor genetic determinants involved in C. jejuni cell shape changes have been characterized. In this review, we highlight known molecular mechanisms and genes involved in CF formation in other bacteria. Since orthologous genes are also present in C. jejuni, we suggest that CF formation in these bacteria is also a regulated and genetically determined process. A possible significance of CF in the lifestyle of this important bacterial pathogen is discussed.
Authors:Smiline As Girija, Jayaseelan Vijayashree Priyadharsini and Arumugam Paramasivam
classes of geneticdeterminants [ 5 ]. Metallo-β-lactamases (MBLs) are rare among these species but prevalence of MBLs was reported as 53.4% in our earlier studies [ 6 ]. However, major contribution for carbapenem resistance was induced through the action