In Silico Genome-Scale Analysis of Molecular Mechanisms Contributing to the Development of a Persistent Infection with Methicillin-Resistant Staphylococcus aureus (MRSA) ST239.

The increasing frequency of isolation of methicillin-resistant Staphylococcus aureus (MRSA) limits the chances for the effective antibacterial therapy of staphylococcal diseases and results in the development of persistent infection such as bacteremia and osteomyelitis. The aim of this study was to identify features of the MRSAST239 0943-1505-2016 (SA943) genome that contribute to the formation of both acute and chronic musculoskeletal infections. The analysis was performed using comparative genomics data of the dominant epidemic S. aureus lineages, namely ST1, ST8, ST30, ST36, and ST239. The SA943 genome encodes proteins that provide resistance to the host's immune system, suppress immunological memory, and form biofilms. The molecular mechanisms of adaptation responsible for the development of persistent infection were as follows: amino acid substitution in PBP2 and PBP2a, providing resistance to ceftaroline; loss of a large part of prophage DNA and restoration of the nucleotide sequence of beta-hemolysin, that greatly facilitates the escape of phagocytosed bacteria from the phagosome and formation of biofilms; dysfunction of the AgrA system due to the presence of psm-mec and several amino acid substitutions in the AgrC; partial deletion of the nucleotide sequence in genomic island vSAß resulting in the loss of two proteases of Spl-operon; and deletion of SD repeats in the SdrE amino acid sequence.

Arcanobacterium pinnipediorum sp. nov., isolated from a harbour seal.

A polyphasic taxonomic study was performed on an unidentified Arcanobacterium-like, Gram-stain-positive bacterium, strain 2710T, isolated from a harbour seal. Comparative 16S rRNA gene sequence analysis showed that this bacterial strain belonged to the genus Arcanobacterium and was related most closely to the type strains of Arcanobacterium phocae (98.4 % similarity) and Arcanobacterium phocisimile (97.5 %). 16S rRNA gene sequence similarities to the type strains of other Arcanobacterium species were between 95.3 and 96.9 %. DNA-DNA hybridization values between strain 2710T and A. phocae DSM 10002T and A. phocisimile LMG 27073T were 4.7 % (reciprocal 56 %) and 23 % (reciprocal 7.7 %), respectively. The presence of the major menaquinone MK-9(H4) and a polar lipid profile with the major compounds diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside supported the affiliation of strain 2710T to the genus Arcanobacterium. The major fatty acids were C16:0, C18:1ω9c, C18:0 and C18:2ω6,9c/anteiso-C18:0. The peptidoglycan structure was of cross-linkage type A5α (l-Lys-l-Lys-d-Glu). Physiological and biochemical tests clearly distinguished the isolate from other members of the genus Arcanobacterium. Based on these tests, it is proposed that this unknown bacterium should be classified as a novel species of the genus Arcanobacterium, with the name Arcanobacterium pinnipediorum sp. nov. The type strain is 2710T ( = DSM 28752T = LMG 28298T).

Draft Genome Sequences of Five Methicillin-Sensitive Staphylococcus aureus Isolates from Skin Lesions in Patients with Atopic Dermatitis in the Russian Federation.

We present here draft genome sequences of five Staphylococcus aureus strains obtained from children suffering from atopic dermatitis. The strains were determined to be of five different sequence types (sequence type 1 [ST1], ST7, ST8, ST15, and ST101) and carried a unique combination of superantigen-like protein (SSL) and serine protease genes.

Phenotypical and Genotypical Properties of an Arcanobacterium pluranimalium Strain Isolated from a Juvenile Giraffe (Giraffa camelopardalis reticulata).

The present study was designed to characterize phenotypically and genotypically an Arcanobacterium pluranimalium strain (A. pluranimalium 4868) following necropsy from a juvenile giraffe. The species identity could be confirmed by phenotypical investigations and by MALDI-TOF MS analysis, by sequencing the 16S rDNA, pluranimaliumlysin encoding gene pla, and glyceraldehyde-3-phosphate dehydrogenase encoding gene gap with sequence similarities to A. pluranimalium reference strain DSM 13483(T) of 99.2%, 89.9%, and 99.1%, respectively. To our knowledge, the present study is the first phenotypic and genotypic characterization of an A. pluranimalium strain isolated from a giraffe.

Further Studies on Arcanobacterium phocisimile: a Novel Species of Genus Arcanobacterium.

Arcanobacterium phocisimile, a newly described species with the type strain A. phocisimile 2698(T) isolated from a vaginal swab of a harbour seal and four additional A. phocisimile strains also isolated from four harbour seals could reliably be identified by phenotypic properties, by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS), and by sequencing the genomic targets 16S rDNA and 16S-23S rDNA intergenic spacer region and the genes rpoB and gap. The A. phocisimile strains investigated in the present study were isolated together with several other bacterial species indicating that the pathogenic importance of A. phocisimile remains unclear. However, the detection of peptidic spectra by MALDI-TOF MS and the presented phenotypic and genotypic approach might help to identify A. phocisimile in future.

Phenotypic and genotypic characteristics of Arcanobacterium haemolyticum isolated from clinical samples in a Danish hospital.

Six Arcanobacterium haemolyticum strains isolated from six patients of two hospitals in Denmark were identified phenotypically, also including matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis, and by genotypic methods. The latter were performed by sequencing 16S rDNA and glyceraldehyde 3-phosphate dehydrogenase encoding gene gap and by amplification of an A. haemolyticum specific region of 16S-23S rDNA intergenic spacer region and 23S rDNA. The six A. haemolyticum strains were further investigated for the presence of seven potential virulence genes encoding arcanolysin, phospholipase D, hemolysin A, CAMP factor family protein, collagen binding protein, neuraminidase A and neuraminidase H which appeared to be present in two (seven virulence genes), two (six virulence genes) and two strains (four virulence genes), respectively. The phenotypic and genotypic properties described in the present study might help to reliably identify and further characterize A. haemolyticum isolated from human patients, a species which seems to be of increasing importance.

Properties of an Arcanobacterium haemolyticum strain isolated from a donkey.

The present study was designed to characterize phenotypically and genotypically an Arcanobacterium haemolyticum strain (A. haemolyticum P646) isolated from a purulent nasal discharge of a donkey. A. haemolyticum P646 showed, compared to sheep blood, an enhanced hemolytic reaction on rabbit blood agar, a synergistic CAMP-like reaction with Streptococcus agalactiae and Rhodococcus equi as indicator strains, a reverse CAMP reaction in the zone of Staphylococcus aureus beta-hemolysin and the typical biochemical properties of this species. The species identity could be confirmed by MALDI-TOF MS analysis, by sequencing the 16S rDNA and glyceraldehyde-3-phosphate dehydrogenase encoding gene gap and by amplification of A. haemolyticum specific parts of 16S-23S rDNA intergenic spacer region and 23S rDNA. A. haemolyticum P646 and the reference strain A. haemolyticum DSM 20595 were further characterized by amplification of the putative virulence genes encoding arcanolysin, phospholipase D, hemolysin A, CAMP factor family protein, a collagen binding protein and two neuraminidases which were present for A. haemolyticum DSM 20595. A. haemolyticum P646 showed a comparable gene spectrum but was negative for the genes encoding collagen binding protein and neuraminidase H. To our knowledge, the present study is the first phenotypic and genotypic characterization of an A. haemolyticum strain isolated from a donkey.