Enhanced adherence of methicillin-resistant Staphylococcus pseudintermedius sequence type 71 to canine and human corneocytes.

Francesca Latronico,Søren Saxmose Nielsen,Arshnee Moodley,Luca Guardabassi

doi:10.1186/1297-9716-45-70

Francesca Latronico, Søren Saxmose Nielsen + Show 2 more

Open Access

https://doi.org/10.1186/1297-9716-45-70

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Journal: Veterinary Research	Publication Date: Jun 24, 2014
Citations: 55	License type: cc-by

Affiliation: University of Copenhagen

Abstract

The recent worldwide spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs is a reason for concern due to the typical multidrug resistance patterns displayed by some MRSP lineages such as sequence type (ST) 71. The objective of this study was to compare the in vitro adherence properties between MRSP and methicillin-susceptible (MSSP) strains. Four MRSP, including a human and a canine strain belonging to ST71 and two canine non-ST71 strains, and three genetically unrelated MSSP were tested on corneocytes collected from five dogs and six humans. All strains were fully characterized with respect to genetic background and cell wall-anchored protein (CWAP) gene content. Seventy-seven strain-corneocyte combinations were tested using both exponential- and stationary-phase cultures. Negative binomial regression analysis of counts of bacterial cells adhering to corneocytes revealed that adherence was significantly influenced by host and strain genotype regardless of bacterial growth phase. The two MRSP ST71 strains showed greater adherence than MRSP non-ST71 (p < 0.0001) and MSSP (p < 0.0001). This phenotypic trait was not associated to any specific CWAP gene. In general, S. pseudintermedius adherence to canine corneocytes was significantly higher compared to human corneocytes (p < 0.0001), but the MRSP ST71 strain of human origin adhered equally well to canine and human corneocytes, suggesting that MRSP ST71 may be able to adapt to human skin. The genetic basis of the enhanced in vitro adherence of ST71 needs to be elucidated as this phenotypic trait may be associated to the epidemiological success and zoonotic potential of this epidemic MRSP clone.

Highlights

Staphylococcus pseudintermedius is the most common bacterial pathogen associated with otitis and pyoderma in dogs, which are the natural hosts of this staphylococcal species
We evaluated the adherence properties of Methicillin-resistant S. pseudintermedius (MRSP) and MSSP, showing that MRSP ST71 adhered better to canine and human corneocytes than MRSP non-ST71 and MSSP
MRSP ST71 has recently been shown to have a greater ability to produce biofilm compared with other sequence type (ST) [9,10]

Summary

Introduction

Staphylococcus pseudintermedius is the most common bacterial pathogen associated with otitis and pyoderma in dogs, which are the natural hosts of this staphylococcal species. The reported carriage prevalences in healthy dogs range between 46 and 92% depending on the study population and methodology used for assessing carriage [1]. Methicillin-resistant S. pseudintermedius (MRSP) were first reported in the United States in 1999 [2] and in 2007 in Europe [3]. An increasing number of studies have documented the rapid spread of MRSP worldwide [4,5,6,7,8]. Some strains are resistant to all antibiotics available for treatment in small animal practice and two dominant clonal lineages have been recognized: ST71 in Europe and ST68 in North America [6]. It has been demonstrated that MRSP ST71 isolates are better

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