Haemorrhagic septicaemia (septicaemic pasteurellosis) in cattle in Baden-Wuerttemberg (Germany)

Abstract

Haemorrhagic septicaemia (septicaemic pasteurellosis) caused by Pasteurella (P.) multocida capsular type B has been diagnosed in cattle in the federal state of Baden-Wuerttemberg (Germany) for the first time in June 2019 since its last official report in Germany in 1986 and its reoccurrence in 2010. A total of 13 cattle succumbed to sudden death on four farms located in the northern part of the Black Forest between June and November 2019. Post-mortem examinations were carried out on seven of these animals and all displayed marked hyperaemia, haemorrhages and oedema in the subcutis and in several inner organs. The pathological-anatomical findings were confirmed by histopathological analyses. Cultivation of P. multocida was successful in five of seven cattle with high bacterial loads in internal organs, and poor growth in two animals. All isolates were clearly identified as P. multocida by MALDI-TOF mass spectrometry and were compared with isolates originating from an HS outbreak in eastern Germany in summer 2010 using Fourier transform infrared (FT-IR) spectroscopy. Molecular capsular and LPS genotyping assigned six of the isolates to the genotypes B:L2 and one to B:L6, respectively. All isolates belonged to the RIRDC MLST genotype ST122. Antimicrobial testing of P. multocida isolates originating from each farm based on the determination of minimal inhibitory concentration (MIC) revealed susceptibility to ampicillin, ceftiofur, enrofloxacin, florfenicol, penicillin G, tetracycline, and tulathromycin. Resistance was determined for spectinomycin.