Antimicrobial susceptibility profiles of porcine mycoplasmas isolated from samples collected in southern Europe

Abstract

Background: Mycoplasma (M.) hyopneumoniae, M. hyorhinis and M. hyosynoviae are significant pathogens for the porcine industry worldwide. The aim of the present study was to determine the antimicrobial susceptibility of six key antimicrobials (tylosin, tilmicosin, tylvalosin, lincomycin, tiamulin and valnemulin) routinely used for treating infections caused by these pathogens. Twenty-seven M. hyopneumoniae, 48 M. hyorhinis and 40 M. hyosynoviae field strains isolated from clinical samples from different Southern European countries between 2013 and 2018 using broth microdilution method were evaluated. Results: Tylvalosin exhibited the highest in vitro activity among the macrolides assayed, with MIC 90 values 4 to 5 twofold dilutions lower than those of tylosin and tilmicosin. The pleuromutilin valnemulin showed one of the highest in vitro activities against the three mycoplasma species. On the contrary, lincomycin exhibited the highest MIC values of the antimicrobials tested. Conclusions: The data obtained in the present study supports the use of pleuromutilins and macrolides for the control of infections caused by porcine mycoplasmas. The use of lincomycin for the treatment of porcine mycoplasma infections should be carefully evaluated due to the presence of circulating field isolates with decreased susceptibility to this antimicrobial.

A case of pericarditis caused by Mycoplasma hyorhinis in a weaned piglet

“…Data regarding M. hyorhinis antimicrobic susceptibility pattern are scarce, however, in agreement with a previous report [ 1 , 16 ], the MIC profile of our strain shows high MIC values in a significant number of molecules, including the macrolides erythromycin, tylosin and tilmicosin. In respect to this, high MIC values for lincomycin have already been reported [ 13 ]. Additionally, the pleuromutilin tiamulin has been suggested as one of the most active antimicrobial in vitro against M. hyorhinis [ 5 ].…”

Development of a molecular biological assay for the detection of markers related to decreased susceptibility to macrolides and lincomycin in Mycoplasma hyorhinis

“…However, a targeted antibiotic treatment is usually inaccessible. Elevated MICs of macrolides or lincomycin to M. hyorhinis isolates have been reported from Japan, Korea, Hungary, Spain, Italy and Portugal since 1996 (Kobayashi et al, 1996(Kobayashi et al, , 2005Jang et al, 2016;Bek} o et al, 2019;Rosales et al, 2020), and point mutations associated with elevated MIC values were described by Kobayashi et al (2005). In the present study, among Hungarian M. hyorhinis field isolates a transversion substitution in the previously examined region, at position 2066 (2058 E. coli numbering) of the 23S rRNA was found, an adenine was replaced by a guanine in the isolates with elevated MIC values.…”

“…Resistances to both of these groups are often linked because of the overlap of the binding sites at the 23S rRNA of the 50S subunit (Py€ or€ al€ a et al, 2014). Mycoplasma hyorhinis is intrinsically resistant to 14-membered macrolides (Ter Laak et al, 1991;Wu et al, 2000) and a decreased susceptibility to 15-and 16-membered macrolides has also been reported (Kobayashi et al, 1996(Kobayashi et al, , 2005Jang et al, 2016;Bek} o et al, 2019;Rosales et al, 2020). In vitro selected resistant mutants and Japanese field isolates have been investigated for resistance-related point mutations (SNPs) in the 23S rRNA gene and the L4, L22 protein genes of the 50S ribosome by Kobayashi et al (2005).…”

Provisional Use of CLSI-Approved Quality Control Strains for Antimicrobial Susceptibility Testing of Mycoplasma (‘Mesomycoplasma’) hyorhinis

“…In the past, several published studies presented antimicrobial susceptibility test results of M. hyorhinis [ 12 , 13 , 16 , 17 , 18 , 19 , 20 ]. Unfortunately, the results of most of these studies are not comparable, due to differing parameters like test media, inoculum size or preparation, incubation temperatures, or incubation times.…”