Causes of spontaneous sow deaths in the farrowing units of 10 Danish sow herds.

This study established the causes and timing of spontaneous sow deaths in the farrowing units of ten Danish sow herds. Herds participated for seven to 15 months during 2018-19. We received data (production data and detailed information on the sows that died) on a total of 126 sows. Fifty-three sows were necropsied, and tissues were evaluated histopathologically. Twenty-four percent of the sows died 0-5 days postpartum. The main cause of death in the study was liver lobe torsion, which was diagnosed in 22 of 53 necropsied sows (42%). Deaths caused by liver lobe torsions were less often seen during the 0-5 day postpartum period compared to deaths caused by other reasons (P = 0.002). Seven of the necropsied sows (13%) died from endotoxaemic shock from retained foetuses. This cause of death was seen in seven of ten herds. These sows typically died 1-3 days postpartum. Pneumonia accounted for 13% of deaths in the necropsied sows, but the majority of these sows originated from one herd experiencing a respiratory outbreak caused by the introduction of M. hyopneumonia. Less prevalent causes of death in the study were torsion of the intestinal segment (8%), suspected cardiovascular collapse (8%), rupture of blood vessels (uterine and nonuterine) (8%), gastric ulcer (4%), sepsis (2%) and liver abscess (2%). We concluded that liver lobe torsion needs further attention to establish the background of this surprisingly prevalent cause of death. Furthermore, a need for procedures that ensure efficient farrowing was identified.

Antibiotic resistance in porcine pathogenic bacteria and relation to antibiotic usage.

BACKGROUND: Optimal treatment and prudent use of antimicrobials for pigs is imperative to secure animal health and prevent development of critical resistance. An important step in this one-health context is to monitor resistance patterns of important animal pathogens. The aim of this study was to investigate the antimicrobial resistance patterns of five major pathogens in Danish pigs during a period from 2004 to 2017 and elucidate any developments or associations between resistance and usage of antibiotics. RESULTS: The minimum inhibitory concentration (MIC) for Escherichia coli, Actinobacillus pleuropneumoniae, Streptococcus suis, Bordetella bronchiseptica, and Staphylococcus hyicus was determined to representatives of antibiotic classes relevant for treatment or surveillance. Escherichia coli isolates were mostly sensitive to fluoroquinolones and colistin, whereas high levels of resistance were observed to ampicillin, spectinomycin, streptomycin, sulfonamides and tetracycline. While resistance levels to most compounds remained relatively stable during the period, resistance to florfenicol increased from 2.1% in 2004 to 18.1% in 2017, likely in response to a concurrent increase in usage. A temporal association between resistance and usage was also observed for neomycin. E. coli serovars O138 and O149 were generally more resistant than O139. For A. pleuropneumoniae, the resistance pattern was homogenous and predictable throughout the study period, displaying high MIC values only to erythromycin whereas almost all isolates were susceptible to all other compounds. Most S. suis isolates were sensitive to penicillin whereas high resistance levels to erythromycin and tetracycline were recorded, and resistance to erythromycin and trimethoprim increasing over time. For S. hyicus, sensitivity to the majority of the antimicrobials tested was observed. However, penicillin resistance was recorded in 69.4-88.9% of the isolates. All B. bronchiseptica isolates were resistant to ampicillin, whereas all but two isolates were sensitive to florfenicol. The data obtained have served as background for a recent formulation of evidence-based treatment guidelines for pigs. CONCLUSIONS: Antibiotic resistance varied for some pathogens over time and in response to usage. Resistance to critically important compounds was low. The results emphasize the need for continuous surveillance of resistance patterns also in pig pathogenic bacteria.

Experimental Pseudomonas aeruginosa mediated rhino sinusitis in mink.

OBJECTIVES: The nasal and sinus cavities in children may serve as reservoirs for microorganisms that cause recurrent and chronic lung infections. This study evaluates whether the mink can be used as an animal model for studying Pseudomonas aeruginosa mediated rhino-sinusitis since there is no suitable traditional animal model for this disease. METHODS: Nasal tissue samples from infected and control mink were fixed in formalin, demineralized, and embedded in paraffin. A histological examination of sections from the infected animals revealed disintegration of the respiratory epithelium lining the nasal turbinates and swelling and edema of the submucosa. The expression of mucins and sialylated glycans was examined using immunohistochemistry. RESULTS: MUC1, MUC2 and MUC5AC were upregulated in the inoculated animals as a much stronger staining was present in the respiratory epithelium in the infected animals compared to the controls. The goblet cells in the nasal epithelium from the infected mink showed high affinity to the Maackia amurensis lectin and anti-asialo GM1 indicating a high concentration of α2-3 sialic acid respectively ßGalNAc1-4Galß containing glycans in these mucin producing cells. The nasal cavity in the infected mink shows features of carbohydrate expression comparable to what has been described in the respiratory system after Pseudomonas aeruginosa infection in humans. CONCLUSION: It is suggested that the mink is suitable for studying Pseudomonas aeruginosa mediated rhino-sinusitis.

Typing of Pseudomonas aeruginosa from hemorrhagic pneumonia in mink (Neovison vison).

Hemorrhagic pneumonia in mink (Neovison vison) is caused by Pseudomonas aeruginosa and is an acute and fatal disease in farmed mink. Earlier work has demonstrated that some outbreaks of hemorrhagic pneumonia are caused by pathogenic strains while most outbreaks are caused by local strains. The objective of this study was to determine the genetic and geographical relationship among outbreaks of hemorrhagic pneumonia by pulsed-field gel electrophoresis typing of P. aeruginosa isolates. Furthermore, chosen isolates were typed by a commercial genotyping method based on single nucleotide polymorphisms (SNPs) and compared to a larger dataset of human and environmental origin. The bacterial isolates were obtained from diagnostic samples from 2002 to 2009 and contained 164 isolates from 95 outbreaks on 90 farms. Our results show that most outbreaks of hemorrhagic pneumonia in mink are caused by distinct strains of P. aeruginosa. We also identified related P. aeruginosa strains which, together with two prevalent but unrelated clones, caused one third of the outbreaks of hemorrhagic pneumonia supporting the sparse literature on this subject. None of the SNP typed strains were identified in a large dataset of human and environmental origin.