RESUMEN

In Staphylococcus aureus, generalized transduction mediated by temperate bacteriophages represents a highly efficient way of transferring antibiotic resistance genes between strains. In the present study, we identified and characterized in detail a new efficiently transducing bacteriophage of the family Siphoviridae, designated ϕJB, which resides as a prophage in the meticillin-resistant S. aureus (MRSA) strain Jevons B. Whole-genome sequencing followed by detailed in silico analysis uncovered a linear dsDNA genome consisting of 43 ,12 bp and comprising 70 ORFs, of which ∼40 encoded proteins with unknown function. A global genome alignment of ϕJB and other efficiently transducing phages ϕ11, ϕ53, ϕ80, ϕ80α and ϕNM4 showed a high degree of homology with ϕNM4 and substantial differences with regard to other phages. Using a model transduction system with a well-defined donor and recipient, ϕJB transferred the tetracycline resistance plasmid pT181 and a penicillinase plasmid with outstanding frequencies, beating most of the above-mentioned phages by an order of magnitude. Moreover, ϕJB demonstrated high frequencies of transferring antibiotic resistance plasmids even upon induction from a lysogenic donor strain. Considering such transducing potential, ϕJB and related bacteriophages may serve as a suitable tool for elucidating the nature of transduction and its contribution to the spread of antibiotic resistance genes in naturally occurring MRSA populations.

Asunto(s)

Staphylococcus aureus Resistente a Meticilina/virología , Profagos/genética , Profagos/aislamiento & purificación , Transducción Genética , Biología Computacional , ADN Viral/química , ADN Viral/genética , Farmacorresistencia Bacteriana , Orden Génico , Transferencia de Gen Horizontal , Genoma Viral , Lisogenia , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Filogenia , Plásmidos , Profagos/ultraestructura , Análisis de Secuencia de ADN , Homología de Secuencia , Siphoviridae/genética , Siphoviridae/aislamiento & purificación , Siphoviridae/ultraestructura , Sintenía , Activación Viral

RESUMEN

Strain CCM 4446T, with notable biodegradation capabilities, was investigated in this study in order to elucidate its taxonomic position. Chemotaxonomic analyses of quinones, polar lipids, mycolic acids, polyamines and the diamino acid of the cell-wall peptidoglycan corresponded with characteristics of the genus Rhodococcus. Phylogenetic analysis, based on the 16S rRNA gene sequence, assigned strain CCM 4446T to the genus Rhodococcus and placed it in the Rhodococcus erythropolis 16S rRNA gene clade. Further analysis of catA and gyrB gene sequences, automated ribotyping with EcoRI restriction endonuclease, whole-cell protein profiling, DNA-DNA hybridization and extensive biotyping enabled differentiation of strain CCM 4446T from all phylogenetically closely related species, i.e., Rhodococcus baikonurensis, Rhodococcus qingshengii, Rhodococcus erythropolis and Rhodococcus globerulus. The results obtained show that the strain investigated represents a novel species within the genus Rhodococcus, for which the name Rhodococcus degradans sp. nov., is proposed. The type strain is CCM 4446T ( = LMG 28633T).

Asunto(s)

Filogenia , Rhodococcus/clasificación , Microbiología del Suelo , Técnicas de Tipificación Bacteriana , ADN Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Grasos/química , Genes Bacterianos , Datos de Secuencia Molecular , Ácidos Micólicos/química , Hibridación de Ácido Nucleico , Peptidoglicano/química , Fosfolípidos/química , Poliaminas/química , ARN Ribosómico 16S/genética , Rhodococcus/genética , Rhodococcus/aislamiento & purificación , Ribotipificación , Análisis de Secuencia de ADN , Suiza , Vitamina K 2/química

RESUMEN

Seven coagulase-negative, oxidase-negative and novobiocin-susceptible staphylococci assigned tentatively as Staphylococcus petrasii were investigated in this study in order to elucidate their taxonomic position. All strains were initially shown to form a genetically homogeneous group separated from remaining species of the genus Staphylococcus by using a repetitive sequence-based PCR fingerprinting with the (GTG)5 primer. Phylogenetic analysis based on 16S rRNA gene, hsp60, rpoB, dnaJ, gap and tuf sequences showed that the group is closely related to Staphylococcus petrasii but separated from the three hitherto known subspecies, S. petrasii subsp. petrasii, S. petrasii subsp. croceilyticus and S. petrasii subsp. jettensis. Further investigation using automated ribotyping, MALDI-TOF mass spectrometry, fatty acid methyl ester analysis, DNA-DNA hybridization and extensive biotyping confirmed that the analysed group represents a novel subspecies within S. petrasii, for which the name Staphylococcus petrasii subsp. pragensis subsp. nov. is proposed. The type strain is NRL/St 12/356(T) ( = CCM 8529(T) = LMG 28327(T)).

Asunto(s)

Filogenia , Staphylococcus/clasificación , Composición de Base , Chaperonina 60/genética , República Checa , ADN Bacteriano/genética , Ácidos Grasos/química , Genes Bacterianos , Humanos , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Oxidorreductasas/genética , ARN Ribosómico 16S/genética , Ribotipificación , Análisis de Secuencia de ADN , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Staphylococcus/genética , Staphylococcus/aislamiento & purificación