Methicillin-resistant staphylococci (MRS) and extended-spectrum beta-lactamases (ESBL)-producing Enterobacteriaceae in companion animals: nosocomial infections as one reason for the rising prevalence of these potential zoonotic pathogens in clinical samples

Abstract

The ongoing change in the relationship between humans and companion animals is hallmarked by the increasing intensive care provided to companion animals in veterinary medicine, resulting in growing numbers of high-risk animal patients. The emergence of nosocomial infections in small animal clinics is one of the major drawbacks of this development, especially in terms of multidrug-resistance and potentially zoonotic pathogens. This mini-review therefore addresses recent findings regarding the increasing prevalence of multi-resistant bacterial pathogens like methicillin-resistant staphylococci (MRS), including Staphylococcus aureus (MRSA) and Staphylococcus pseudintermedius (MRSP) as well as extended-spectrum beta-lactamases (ESBL)-producing Enterobacteriaceae in companion animals. Along with the steady increase of nosocomial infection rates in veterinary clinics, particular attention has recently been drawn to the genetic background of multi-resistant strains, resulting in the identification of certain genetic lineages which frequently appear in both, human and animal samples. These sequence types (ST), included ST254, ST8 and ST22 in terms of MRSA and ST131, ST405 and ST648 for ESBL-producing E. coli. The interspecies distribution of these STs resulted in the assumption that certain extended-host spectrum genotypes (EHSG) might exist both for MRS and ESBL-producing E. coli. These initial findings underline the necessity to investigate the major molecular or functional driving forces facilitating interspecies transferability of such EHSG strains. Due to the zoonotic potential of these multi-resistant bacteria, another aspect of the changing social role of companion animals needs to be addressed: the close contact of pets with their owners, resulting in presumptive new transmission and infection routes. We therefore envision retaliatory actions like initial surveillance and monitoring programs not only in livestock, but also particularly in companion animals. Interdisciplinary approaches including human and veterinary experts should be implemented to develop reliable investigation procedures with respect to the current reality of animal owners and their pets. Additionally, consequent basic hygienic measures, prudent use of antimicrobials in companion animals and efforts regarding implementation of antibiotic stewardships should be fostered.