Antimicrobial resistance of E. coli and Enterococcusspp. isolated from swine and cattle in 2016-2020 in Estonia

Abstract

Antimicrobial resistance is recognized as one of the major global health threats globally. It is a problem relating to “One Health” concept, therefore monitoring the resistance in bacteria from food-producing animals is necessary. The objective of this thesis was to investigate and describe the occurrence of antimicrobial resistance of Escherichia coli, Enterococcus faecium and Enterococcus faecalis isolated from healthy and diseased pigs and cattle in Estonia during 2016 to 2020. Commensal E. coli and Enterococcus spp. were collected from caecal samples of fattening pigs at slaughter and resistance was determined using microdilution method. E. coli from diseased animals was isolated from clinical submissions of pigs and cattle and resistance was determined using disc-diffusion assay. Both bacteria studied were found to have developed resistance against multiple antibiotics. Commensal E. coli isolates had highest resistance against tetracycline (19,4%), ampicillin (17,9%), trimethoprim (16,4%) and sulfamethoxazole (14,9%). E. coli isolates from clinical submissions of pigs had highest resistance against amoxicillin (38,1%), tetracycline (23,8%) and trimethoprim (13,1%). E. coli isolates from clinical submissions of cattle had highest resistance against tetracycline (62,3%), ampicillin (49,3 %), sulfamethoxazole-trimethoprim (40,6%) and enrofloxacin (37,7%). E. faecalis had developed highest resistance against tetracycline (72,3%), erythromycin (46,8%) and chloramphenicol (25,5%). E. faecium had highest resistance against erythromycin (41,5%), quinipristin/dalfopristin (25,5%) and tetracycline (23,4%). Isolates from healthy pigs had higher susceptibility rates and lower multidrug resistance rates than isolates from diagnostic submissions. No significant changes occurred during the study years. Resistance against critically important antibiotics is generally low in commensal bacteria.

Mikroobide resistentsus on tänapäeval kogu maailmas üks peamisi probleeme tervishoiusüsteemis. See on probleem ka “Üks Tervis” kontseptsiooni mõistes, mistõttu on väga oluline monitoorida ka loomade mikroobide resistentsuse arengut. Selle töö eesmärk oli uurida tervetelt ja haigetelt sigadelt ja veistelt Eestis aastatel 2016 – 2020 isoleeritud Escherichia coli, Enterococcus faecium’i ja Enterococcus faecalis’e antibiootikumiresistentsust. Kommensaalsed E. coli ja Enterococcus spp. koguti tapamajades nuumsigade käärsoolest, resistentsust uuriti mikrodilutsiooni meetodiga. E. coli haigetelt loomadelt isoleeriti veterinaarleboratooriumisse toodud proovidest ning resistentsust uuriti diskdiffusiooni meetodiga. Kommensaalsed E. coli isolaadid olid kõige resistentsemad tetratsükliini (19,4%), ampitsilliini (17,9%), trimetoprimi (16,4%) ja sulfametoksasooli (14,9%) suhtes. E. coli isolaadid haigetelt sigadelt olid kõige resistentsemad amoksitsilliini (38,1%), tetratsükliini (23,8%) ja trimetoprimi (13,1%) suhtes. E. coli isolaadid haigetelt veistelt olid resistentsed tetratsükliini (62,3%), ampitsilliini (49,3 %), sulfametoksasool-trimethoprimi (40,6%) ja enrofloksatsiini (37,7%) suhtes. E. faecalis oli kõige resistentsem tetratsükliini (72,3%), erütromütsiini (46,8%) ja klooramfenikooli (25,5%) suhtes. E. faecium oli resistentseim erütromütsiini (41,5%), quinupristiin/dalfopristiini (25,5%) ja tetratsükliini (23,4%) suhtes. Kokkuvõttes saab ütelda, et tervetelt sigadelt isoleeritud mikroobid olid antibiootikumide suhtes tundlikumad ning nende hulgas oli vähem multiresistentseid tüvesid võrreldes haigetelt sigadelt isoleeritud mikroobidega. Resistentsuses ei olnud uuringus olnud aastate jooksul erilisi muutusi. Kommensaalsete bakterite resistentsus kriitilise tähtsusega antibiootikumide suhtes oli uuringuaastete jooksul madal.