Open chest and pericardium facilitate transpulmonary passage of venous air emboli

Background: Transpulmonary passage of air emboli can lead to fatal brain- and myocardial infarctions. We studied whether pigs with open chest and pericardium had a greater transpulmonary passage of venous air emboli than pigs with closed thorax. Methods: We allocated pigs with verified closed foramen ovale to venous air infusion with either open chest with sternotomy and opening of the pleura and pericardium (n = 8) or closed thorax (n = 16). All pigs received a five-hour intravenous infusion of ambient air, starting at 4-6 mL/kg/h and increased by 2 mL/kg/h each hour. We assessed transpulmonary air passage by transesophageal M-mode echocardiography and present the results as median with inter-quartile range (IQR). Results: Transpulmonary air passage occurred in all pigs with open chest and pericardium and in nine pigs with closed thorax (56%). Compared to pigs with closed thorax, pigs with open chest and pericardium had a shorter to air passage (10 minutes (5-16) vs. 120 minutes (44-212), P < .0001), a smaller volume of infused air at the time of transpulmonary passage (12 mL (10-23) vs.170 mL (107-494), P < .0001), shorter time to death (122 minutes (48-185) vs 263 minutes (248-300, P = .0005) and a smaller volume of infused air at the time of death (264 mL (53-466) vs 727 mL (564-968), P = .001). In pigs with open chest and, infused air and time to death correlated strongly (r = 0.95, P = .001). Conclusion: Open chest and pericardium facilitated the transpulmonary passage of intravenously infused air in pigs

Reproductive Performance, Udder Health, and Antibiotic Resistance in Mastitis Bacteria isolated from Norwegian Red cows in Conventional and Organic Farming

<p>Abstract</p> <p>Background</p> <p>The objectives of this study were to investigate whether there were differences between Norwegian Red cows in conventional and organic farming with respect to reproductive performance, udder health, and antibiotic resistance in udder pathogens.</p> <p>Methods</p> <p>Twenty-five conventional and 24 organic herds from south-east and middle Norway participated in the study. Herds were matched such that geographical location, herd size, and barn types were similar across the cohorts. All organic herds were certified as organic between 1997 and 2003. All herds were members of the Norwegian Dairy Herd Recording System. The herds were visited once during the study. The relationship between the outcomes and explanatory variables were assessed using mixed linear models.</p> <p>Results</p> <p>There were less > 2nd parity cows in conventional farming. The conventional cows had higher milk yields and received more concentrates than organic cows. Although after adjustment for milk yield and parity, somatic cell count was lower in organic cows than conventional cows. There was a higher proportion of quarters that were dried off at the herd visit in organic herds. No differences in the interval to first AI, interval to last AI or calving interval was revealed between organic and conventional cows. There was no difference between conventional and organic cows in quarter samples positive for mastitis bacteria from the herd visit. Milk yield and parity were associated with the likelihood of at least one quarter positive for mastitis bacteria. There was few <it>S. aureus </it>isolates resistance to penicillin in both management systems. Penicillin resistance against Coagulase negative staphylococci isolated from subclinically infected quarters was 48.5% in conventional herds and 46.5% in organic herds.</p> <p>Conclusion</p> <p>There were no large differences between reproductive performance and udder health between conventional and organic farming for Norwegian Red cows.</p

Clinical mastitis in ewes; bacteriology, epidemiology and clinical features

<p>Abstract</p> <p>Background</p> <p>Clinical mastitis is an important disease in sheep. The objective of this work was to identify causal bacteria and study certain epidemiological and clinical features of clinical mastitis in ewes kept for meat and wool production.</p> <p>Methods</p> <p>The study included 509 ewes with clinical mastitis from 353 flocks located in 14 of the 19 counties in Norway. Clinical examination and collection of udder secretions were carried out by veterinarians. Pulsed-field gel electrophoresis (PFGE) was performed on 92 <it>Staphylococcus aureus </it>isolates from 64 ewes.</p> <p>Results and conclusion</p> <p><it>S. aureus </it>was recovered from 65.3% of 547 clinically affected mammary glands, coagulase-negative staphylococci from 2.9%, enterobacteria, mainly <it>Escherichia coli</it>, from 7.3%, <it>Streptococcus </it>spp. from 4.6%, <it>Mannheimia haemolytica </it>from 1.8% and various other bacteria from 4.9%, while no bacteria were cultured from 13.2% of the samples. Forty percent of the ewes with unilateral clinical <it>S. aureus </it>mastitis also had a subclinical <it>S. aureus </it>infection in the other mammary gland. Twenty-four of 28 (86%) pairs of <it>S. aureus </it>isolates obtained from clinically and subclinically affected mammary glands of the same ewe were indistinguishable by PFGE. The number of identical pairs was significantly greater than expected, based on the distribution of different <it>S. aureus </it>types within the flocks. One-third of the cases occurred during the first week after lambing, while a second peak was observed in the third week of lactation. Gangrene was present in 8.8% of the clinically affected glands; <it>S. aureus </it>was recovered from 72.9%, <it>Clostridium perfringens </it>from 6.3% and <it>E. coli </it>from 6.3% of the secretions from such glands. This study shows that <it>S. aureus </it>predominates as a cause of clinical ovine mastitis in Norway, also in very severe cases. Results also indicate that <it>S. aureus </it>is frequently spread between udder halves of infected ewes.</p

Novel Plasmid-Borne Gene qacJ Mediates Resistance to Quaternary Ammonium Compounds in Equine Staphylococcus aureus, Staphylococcus simulans, and Staphylococcus intermedius

We identified a novel plasmid-borne gene (designated qacJ) encoding resistance to quaternary ammonium compounds (QACs) in three staphylococcal species associated with chronic infections in four horses. qacJ was located on a 2,650-bp plasmid (designated pNVH01), a new member of the pC194 family of rolling-circle replication plasmids. The 107-amino-acid protein, QacJ, showed similarities to known proteins of the small multidrug resistance family: Smr/QacC (72.5%), QacG (82.6%), and QacH (73.4%). The benzalkonium chloride MIC for a qacJ-containing recombinant was higher than those for otherwise isogenic recombinants expressing Smr, QacG, or QacH. Molecular epidemiological analyses by pulsed-field gel electrophoresis suggested both the clonal spread of a qacJ-harboring Staphylococcus aureus strain and the horizontal transfer of pNVH01 within and between different equine staphylococcal species. The presence of pNVH01 of identical nucleotide sequence in different staphylococcal species suggests that recent transfer has occurred. In three of the horses, a skin preparation containing cetyltrimethylammonium bromide had been used extensively for several years; this might explain the selection of staphylococci harboring the novel QAC resistance gene

Distribution of 318 cases of clinical mastitis in relation to weeks of lactation

<p><b>Copyright information:</b></p><p>Taken from "Clinical mastitis in ewes; bacteriology, epidemiology and clinical features"</p><p>http://www.actavetscand.com/content/49/1/23</p><p>Acta Veterinaria Scandinavica 2007;49(1):23-23.</p><p>Published online 24 Sep 2007</p><p>PMCID:PMC2048968.</p><p></p

Intraosseous fluid resuscitation causes systemic fat emboli in a porcine hemorrhagic shock model

Background Intraosseous cannulation can be life-saving when intravenous access cannot be readily achieved. However, it has been shown that the procedure may cause fat emboli to the lungs and brain. Fat embolization may cause serious respiratory failure and fat embolism syndrome. We investigated whether intraosseous fluid resuscitation in pigs in hemorrhagic shock caused pulmonary or systemic embolization to the heart, brain, or kidneys and if this was enhanced by open chest conditions. Methods We induced hemorrhagic shock in anesthetized pigs followed by fluid-resuscitation through bilaterally placed tibial (hind leg) intraosseous cannulas. The fluid-resuscitation was limited to intraosseous or i.v. fluid therapy, and did not involve cardiopulmonary resuscitation or other interventions. A subgroup underwent median sternotomy with pericardiectomy and pleurotomy before hemorrhagic shock was induced. We used invasive hemodynamic and respiratory monitoring including Swan Ganz pulmonary artery catheter and transesophageal echocardiography and obtained biopsies from the lungs, heart, brain, and left kidney postmortem. Results All pigs exposed to intraosseous infusion had pulmonary fat emboli in postmortem biopsies. Additionally, seven of twenty-one pigs had coronary fat emboli. None of the pigs with open chest had fat emboli in postmortem lung, heart, or kidney biopsies. During intraosseous fluid-resuscitation, three pigs developed significant ST-elevations on ECG; all of these animals had coronary fat emboli on postmortem biopsies. Conclusions Systemic fat embolism occurred in the form of coronary fat emboli in a third of the animals who underwent intraosseous fluid resuscitation. Open chest conditions did not increase the incidence of systemic fat embolization