Utvärdering av provtagningsmetodiken vid luftvägsinfektion hos kalv

Luftvagsinfektioner ar vanligt forekommande hos svenska kalvar, framfor allt i specialiserad slaktnotsuppfodning. Vid utredning av problematiken ar provtagning, isolering av bakterier och resistensbestamning vasentliga delar. Provtagning med en provtagningspinne i kalvens nashala ar den provtagningsmetod som rutinmassigt anvands. En forbattrad provtagningsmetodik, till exempel vilken provtagningspinne som anvands, skulle kunna oka chanserna att isolera de sjukdomsframkallande bakterierna. I studien besoktes tio besattningar med specialiserad slaktnotsuppfodning for provtagning av totalt 100 kalvar. Varje kalv provtogs med 3-4 olika provtagningspinnar (A-svabb, E-svabb, uteruspinne och MWE-svabb) med syftet att jamfora de olika provtagningspinnarnas formaga att ge relevanta bakteriefynd. A-svabben som oftast anvands pavisades ge signifikant samre isoleringsfrekvens an ovriga svabbar. E-svabben var den svabb som upplevdes vara den basta kompromissen mellan isoleringsfrekvens, pris och anvandarvanlighet. Studien pavisade inga signifikanta skillnader mellan bakteriefloran hos kalvar med respektive utan luftvagssjukdom. Resistensbestamning av isolerade bakteriestammar pavisade penicillin- och ampicillinresistent Pasteurella multocida i tre besattningar, en egenskap som endast pavisats vid tva tillfallen tidigare i Sverige. Mycoplasma bovis, en forhallandevis ny bakterie i Sverige som riskerar att orsaka svarbehandlad luftvagssjukdom, pavisades i tva besattningar. Dessa fynd talar for betydelsen av provtagning och smittskyddsarbete. SUMMARY Respiratory infection is common among Swedish calves, not least in specialized beef production. While investigating the issue, sampling, bacterial isolation and antimicrobial susceptibility testing are essential elements. Sampling with a swab into the nasal cavity of the calf, is the method of sampling routinely used. An improved methodology of sampling, by such as choice of swab, has the potential to increase the ability to isolate the disease-causing bacteria. The study included ten herds of beef cattle for sampling of in total one hundred calves. Each calf was sampled with 3-4 different types of swabs (A-swab, E-swab, uterine swab and MWEswab) with the aim of comparing the capacity of the swabs to yield relevant bacteriological findings. The swab mainly used in practice, the A-swab, was found to give a significantly lower isolation frequency than the other swabs tested. The E-swab was perceived to be the best compromise between isolation rate, cost and ease of use. The study showed no significant difference between the nasal bacterial flora of calves with and without respiratory symptoms. Antimicrobial susceptibility testing of isolated bacterial strains demonstrated penicillin and ampicillin resistent Pasteurella multocida in three herds, a property only found twice before in Sweden. Mycoplasma bovis, a relatively rare bacterium in Sweden and which is known to cause respiratory disease that is hard to cure, was detected in two herds. These findings highlight the importance of sampling and of preventive disease control.