Applying definitions for multidrug resistance, extensive drug resistance and pandrug resistance to clinically significant livestock and companion animal bacterial pathogens

Abstract

Standardized definitions for MDR are currently not available in veterinary medicine despite numerous reports indicating that antimicrobial resistance may be increasing among clinically significant bacteria in livestock and companion animals. As such, assessments of MDR presented in veterinary scientific reports are inconsistent. Herein, we apply previously standardized definitions for MDR, XDR and pandrug resistance (PDR) used in human medicine to animal pathogens and veterinary antimicrobial agents in which MDR is defined as an isolate that is not susceptible to at least one agent in at least three antimicrobial classes, XDR is defined as an isolate that is not susceptible to at least one agent in all but one or two available classes and PDR is defined as an isolate that is not susceptible to all agents in all available classes. These definitions may be applied to antimicrobial agents used to treat bovine respiratory disease (BRD) caused by Mannheimia haemolytica, Pasteurella multocida and Histophilus somni and swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, P. multocida and Streptococcus suis, as well as antimicrobial agents used to treat canine skin and soft tissue infections (SSTIs) caused by Staphylococcus and Streptococcus species. Application of these definitions in veterinary medicine should be considered static, whereas the classification of a particular resistance phenotype as MDR, XDR or PDR could change over time as more veterinary-specific clinical breakpoints or antimicrobial classes and/or agents become available in the future.

Staphylococcus spp. isolated from wild birds apprehended in the local illegal trade in Rio de Janeiro, Brazil, and relevance in public health

“…Presently, there were isolates with multidrug resistance profile that were also possible to detect either the mecA or the blaZ genes (Table 3). Multidrug resistance is frequently observed in staphylococci isolates, and this requires methodologies performed in accordance with an internationally accepted procedure, as presently used, such as those published by the Clinical and Laboratory Standards Institute-Veterinary Antimicrobial Susceptibility Testing (CLSI-VAST) and quality controls strains to reduce errors in interpretation criteria (Sweeney et al 2018). Multifactorial mechanisms of resistance is an evolving phenomenon among staphylococci and mobile genetic elements, such as transposons/integrons, increasing the potential enrichment of multidrug resistance in these isolates as described by literature (Li et al, 2007;McCaullum et al 2010).…”

Molecular Detection of Multidrug Resistant Salmonella Species Isolated from Broiler Farm in Bangladesh

“…The antibiogram test was performed by disk diffusion method on Mueller-Hinton agar (Hi Media, India) plates with a concentration of bacteria equivalent to 0.5 McFarland standard, incubated for 18-24 h aerobically at 37 • C. The results of the antibiogram test were recorded as sensitive, intermediately sensitive, or resistant and the diameters of the zones of inhibition were compared with the diameters of interpretative tables provided by the Clinical and Laboratory Standards Institute (CLSI) [55]. Salmonella isolates that were found to be resistant to multiple antimicrobials (at least 3 classes of antibiotics) were considered as MDR [56]. Table 5.…”

Fecal shedding of Salmonella spp., Clostridium perfringens, and Clostridioides difficile in dogs fed raw meat-based diets in Brazil and their owners’ motivation

“…isolates (7/8 = 87.5%) were resistant to at least one of the seven different classes of antimicrobials tested (Table 2). Additionally, three Salmonella enterica of serovars S. Typhimurium, S. Panama, and S. Saintpaul, from dogs fed RMBD, were multidrug resistant (resistant to three or more antimicrobial classes, according to Sweeney et al [49]). It is interesting to note that this resistance pattern included antimicrobials that are largely used for human and veterinary medicine, such as oxytetracycline, streptomycin, and trimethoprim/sulfamethoxazole [44].…”