ABSTRACT
The frequency and mechanisms of resistance to macrolides in Streptococcus.pyogenes isolated within 3 periods: 2011-2012 (246 strains), 2013-2014 (273 strains) and from January to November of 2015 (120 strains) were studied. The strains of S.pyogenes (639) were isolated from 17107 nasopharyngeal, vaginal and middle ear discharge smears of children on their visits to physiciants or hospitalization at somatic hospital departments. The susceptibility was tested by the disk diffusion method and E-test strips. Identification of the mechanisms of resistance to macrolides and lincosamides included phenotypic and molecular genetic methods. PCR was used to determine ermB and mef genes in 23 erythromycin resistant isolates. As compared to 2011-2012, resistance of S.pyogenes to macrolides increased from 5 to 16% in 2015 and that to clindamycin from 2 to 10%. Among 23 erythromycin resistant strains 6 (26.1%) belonged to the M phenotype, 3 (13.0%) belonged to the iMLS(b) phenotype and 14 (60.9%) belonged to the cMLS(b) pheno-type. The results of detecting the macrolide resistance genes in S.pyogenes showed that only 26.1% of the isolates expressed the mefA gene. The predominant share (65.2%) of the erythromycin resistant isolates possesed the ermB gene as a determinant and in 4.3% of the isolates the ermB gene was associatied with the mefgene. No resistance genes were detected 1 isolate. Therefore, the main mech- anism that determined resistance of S.pyogenes to macrolides was methylation of ribosomes mediated by the ermB gene.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Drug Resistance, Multiple, Bacterial/genetics , Streptococcal Infections/microbiology , Streptococcus pyogenes/genetics , Azithromycin/pharmacology , Bacterial Proteins/metabolism , Child , Clarithromycin/pharmacology , Clindamycin/pharmacology , Ear, Middle/microbiology , Ear, Middle/pathology , Erythromycin/pharmacology , Female , Gene Expression , Genotype , Humans , Male , Membrane Proteins/genetics , Membrane Proteins/metabolism , Methylation/drug effects , Microbial Sensitivity Tests , Nasopharynx/microbiology , Nasopharynx/pathology , Phenotype , Ribosomes/drug effects , Ribosomes/genetics , Ribosomes/metabolism , Streptococcal Infections/drug therapy , Streptococcal Infections/pathology , Streptococcus pyogenes/classification , Streptococcus pyogenes/drug effects , Streptococcus pyogenes/isolation & purification , Vagina/microbiology , Vagina/pathologyABSTRACT
The nucleotide sequence of barley C-hordein gene lambda CH4 and its flanking regions of 2820 bp length was determined. The gene contains no introns and codes for 310 amino acid long polypeptide. The 94% of the deduced amino acid sequence of the mature protein (291 amino acids) is made up of a repeating octapeptide motiff, PQQPEPQQ, which is repeated throughout the peptide chain between a unique 12 amino acid long NH2 terminal and a unique 6 amino acid long COOH-terminal end. In the 5' non-coding region there are TATA-, AGGA-, CAAT-and "endosperm" boxes. The 3' non-coding region has two polyadenylation signals. Compared with the published C-hordein sequences, our gene contains a number of insertions, deletions and substitutions. In the 3'-untranslated region there are two insertions 157 and 23 bp long. For the longer insertion no significant homology was found in the Gene Bank datebase. This insertion is the largest known rearrangement in the otherwise highly conservative surroundings of barley storage protein genes.
Subject(s)
Hordeum/genetics , Plant Proteins/genetics , Amino Acid Sequence , Base Sequence , Cloning, Molecular , DNA Transposable Elements , Gene Deletion , Gene Rearrangement , Glutens , Molecular Sequence Data , Sequence Alignment , Sequence Homology, Nucleic AcidABSTRACT
A study was made of the transmissivity range of the genetic transfer factors pAP38, pAP39, pAP41 and pAP42 identified in E. coli. It was demonstrated that these factors are not capable of transfer to the cells of P. putida, P. fluorescens, R. leguminosarum, A. lipoferum, A. tumefaciens. Factor pAP42 is mobilized to transfer to P. putida and R. leguminosarum with the aid of plasmid RP4. It is assumed that in the course of mobilization, the cointegrative structures are formed between plasmids pAP42 and RP4.
Subject(s)
F Factor , Plasmids , Crosses, Genetic , DNA Transposable Elements , Escherichia coli/genetics , Gene Expression Regulation , Genetic Markers , Pseudomonas/genetics , Rhizobium/genetics , Spirillum/geneticsABSTRACT
Genetic transfer factors pAP38, pAP39 and pAP41 can be transferred to E. coli, both typed and untypecd, as well as to Erwinia and Hafnia strains, with different frequency (10(-2) to 10(-8)). The transconjugates thus obtained possess donor activity and can transfer the factors they have received to recipient E. coli strains. After transfer these factors are stably maintained in a new host for at least 10 days. Under the action of ethidium bromide or elevated temperature the elimination of the transfer factors from host bacteria is observed. The studied transfer factors pAP38, pAP39 and pAP41 (F-like factors) are plasmids fi+.
