Staphylococcus aureus isolates from Eurasian Beavers (Castor fiber) carry a novel phage-borne bicomponent leukocidin related to the Panton-Valentine leukocidin

Abstract

Staphylococcus aureus can be a harmless coloniser, but it can also cause severe infections in humans, livestock and wildlife. Regarding the latter, only few studies have been performed and knowledge on virulence factors is insufficient. The aim of the present study was to study S. aureus isolates from deceased wild beavers (Castor fiber). Seventeen isolates from eleven beavers, found in Germany and Austria, were investigated. Antimicrobial and biocide susceptibility tests were performed. Isolates were characterised using S. aureus-specific DNA microarrays, spa typing and whole-genome sequencing. From two isolates, prophages were induced by mitomycin C and studied by transmission electron microscopy. Four isolates belonged to clonal complex (CC) 8, CC12, and CC398. Twelve isolates belonged to CC1956 and one isolate was CC49. The CC49 and CC1956 isolates carried distinct lukF/S genes related to the Panton-Valentine leukocidin (PVL) from human isolates of S. aureus. These genes were located on related, but not identical, Siphovirus prophages. The beavers, from which those isolates originated, suffered from abscesses, purulent organ lesions and necrotising pneumonia, i.e., clinical manifestations resembling symptoms of severe PVL-associated disease in humans. It might thus be assumed that the “Beaver Leukocidin (BVL, lukF/S-BV)”-positive strains are beaver-specific pathogens, and further studies on their clinical role as well as on a possible transmissibility to other species, including humans, are warranted.

Antimicrobial and Biocide Resistance among Feline and Canine Staphylococcus aureus and Staphylococcus pseudintermedius Isolates from Diagnostic Submissions

“…Moreover, the highest MIC value for benzalkonium chloride measured was 0.0005%, which is far below the concentration used for disinfection of the skin of 0.01–0.2% [ 42 ]. This was in accordance with previous studies investigating 19 S. aureus isolates from horses [ 43 ] and 17 isolates from beavers [ 44 ]. In comparison, a study on S. aureus from primates identified some isolates with a slightly elevated MICs of 0.0004%, which harbored the qacC gene [ 45 ].…”

“…Again, the highest chlorhexidine MIC measured in this study (0.00025%) was far below the concentration of up to 4% in shampoos for veterinary applications [26,27]. Moreover, these MICs were in accordance with the results obtained by testing the isolates from horses [43] and beavers [44] No polyhexanide-or octenidine-containing formulations are currently approved for veterinary use. The MICs for polyhexidine and octenidine were also in a similar range to those determined for the S. aureus isolates from beavers, with MICs for polyhexanide of 0.000125-0.001% and for octenidine of 0.00006-0.00025% [44].…”

Development of Quality Control Ranges for Biocide Susceptibility Testing

“…The recently developed BST has already been used in some studies to test S. aureus from horses [19], primates [20], and beavers [21] as well as E. coli from animal origin [22,23]. It should be noted that conventional biocides, such as the ones described during this study, have a toxic potential.…”

Sequence Analysis of Novel Staphylococcus aureus Lineages from Wild and Captive Macaques

“…All isolates of all CCs carried the gamma leukocidin locus ( lukF / S-hlg , hlgA ) as well as leukocidin genes lukD / E (see Table 2 ) and lukA / B (= lukG / H or lukX / Y [ 35 , 44 , 45 , 46 ]). The phage-borne leukocidin lukS / F-PV (encoding Panton–Valentine leukocidin) as well as animal-associated related genes lukM / lukF-P83 , lukP / Q [ 47 ], and lukS / F - BV [ 48 ] were absent from all study strains, although lukS / F-PV was previously observed in human isolates of CC2990 (author’s unpubl. observation).…”

“…There are several leukocidins that clearly determine host species specificity, rendering S. aureus pathogenic for humans ( lukS / F-PV ), ruminants ( lukM / F-P83 ), horses ( lukP / Q , [ 47 ]), or beavers ( lukS / F-BV ; [ 48 ]), but these were all are absent from the study strains. There was also no evidence for novel leukocidin genes.…”