Genome Sequences of Two Staphylococcus aureus Ovine Strains That Induce Severe (Strain O11) and Mild (Strain O46) Mastitis

Abstract

Staphylococcus aureus is a major etiological agent of mastitis in ruminants. We report here the genome sequences of two ovine strains that were isolated from gangrenous (strain O11) and subclinical (strain O46) ewe mastitis. Both strains belong to the same clonal complex. Despite this close genotypic relationship, the two isolates were shown to reproducibly induce highly divergent types of infections, either severe (O11) or mild (O46) mastitis, in an experimental ewe model.Staphylococcus aureus is one of the main pathogens involved in ruminant mastitis. Staphylococcal mastitis severity is highly variable, ranging from subclinical to gangrenous mastitis. Severity partly relies on bacterial factors. S. aureus strains isolated from bovine or ovine-caprine hosts differ from human isolates, as revealed previously (3), and genomic data regarding ruminant isolates are still scarce (4, 6). There is thus a need for more genomic data to better understand mastitis and identify bacterial factors involved in the severity of the infection.We characterized two S. aureus ovine strains, which were shown to be clonally related (9) and reproducibly induced severe (strain O11) and mild (strain O46) mastitis in experimental ewe mastitis (8).We sequenced the two genomes by using an Illumina Genome Analyzer GAII (Fasteris, Geneva, Switzerland).Base calling was performed with GAPipeline 1.4.0 software; a total of 27.6 million reads (pass filter) were obtained. After bar code selection, 13.9 and 11.8 million reads of 71 bases in length were obtained for O11 and O46, respectively. Sequence reads were de novo assembled with the Edena assembler (5), version 3.0. Assembly resulted in 87 contigs (sum, 2.77 Mbp; N 50 , 92.2 kbp; maximum, 266 kbp; minimum, 211 bp) and 96 contigs (sum, 2.81 Mbp; N 50 , 76.5 kbp; maximum, 209 kbp; minimum, 228 bp) for O11 and O46, respectively. (N 50 is contig size such that 50% of the entire assembly is contained in contigs equal to or larger than this size.) Totals of 2,787 and 2,822 coding sequences were detected for O11 and O46, respectively, by using Glimmer3 (PMID no. 17237039). Sequence comparison and single nucleotide polymorphism (SNP) calling were performed with MUMmer (7). Over 53% of the genes were assigned to specific subsystem categories by RAST (1). Gene products were submitted to protein location prediction using the software package SurfGϩ (2).The overall O11 and O46 genomes share high similarity to the ED133 genome. The great majority of the genes were common to both strains, except for an additional prophage (containing 42 coding sequences [CDSs]) detected in the O46 genome, which was not found in ED133 either. The putative O46 prophage genes are functionally unknown.

Detection of mecC-Positive Staphylococcus aureus (CC130-MRSA-XI) in Diseased European Hedgehogs (Erinaceus europaeus) in Sweden

“…The animal-specific leukocidin, lukM/lukF-P83 , was absent from both, hedgehog and human isolates [7], although it has been observed in (methicillin susceptible) sheep and rat isolates of CC130 [7], [25]. The “ etD2 ” exfoliative toxin homologue gene has been found in genome sequences of human and animal strains of CC130 [7], [25] as well as in the animal-specific staphylococcal species Staphylococcus hyicus (where it was named “ shetb ” ¸ GenBank AB036767.1) and Staphylococcus pseudintermedius (“ exi ” or “ expb ”; GenBank AB489850.1 and AB569087.1). A formation of skin blisters and exfoliation upon injection into neonatal mice has been observed [30] and a role in canine pyoderma has been suggested [31] as well as a role in exudative epidermitis of pigs [32].…”

“…The DNA sequence of a novel exfoliative toxin homologue, putatively named etD2 , that was detected as part of the present study in an Irish CC130 genome sequence [7] as well as in two other CC130 genomes (GenBank accession number AEUQ01000009.1, bases 161312 to 162153 and AEUR01000016.1, bases 44379 to 45221 [25]) was submitted to GenBank under accession number HF563069. The presence of this gene in both isolates was investigated by PCR with primers as listed in Table 1.…”

An approach to identifying drug resistance associated mutations in bacterial strains

“…Drug susceptibility data were collected from the following sources: (i) publications issued together with the fully sequenced genomes: USA300_TCH1516 and USA300_TCH959 [28], MRSA252 and MSSA476 [29], 04-02981 [30], T0131 [31], ST398 [32], COL [33], JKD6008 [34], 16 K [35], TW20 [36], Newman [37], RN4220 [38], O46 and O11 [39], RF122 [40], Mu3 [41], MRSA252 [29], CF-Marseille [42], N315 and Mu50 [43], MW2 [44], MSHR1132 [45], ECT-R_2 [46], JH1 and JH9 [17], ED98 [47], JKD6159 [48], LGA251 [49], ED133 [50]; (ii) NARSA project http://www.narsa.net; (iii) email exchange with the authors of publications related to strains ST398 and TW20; and (iv) other publications found by searching of related literature [21,23,33,37,51-98]. The complete collected phenotype data are available in the supplementary table (additional file 1).…”

A central composite rotatable design (CCRD) approach to study the combined effect of antimicrobial agents against bacterial pathogens

“…S. aureus O46 was isolated from a ewe diagnosed with mild mastitis (Le Marechal et al 2011) and was cultivated overnight under microaerophilic conditions, at 37°C, in Mueller-Hinton (MH) media.…”