Characterization of Fusobacterium necrophorum subsp. necrophorum outer membrane proteins.

Liver abscesses are of major economic importance to the cattle industry. These are mainly associated with the presence of Fusobacterium necrophorum, a non-spore forming and Gram-negative anaerobe. There are two main subspecies, F. necrophorum subspecies necrophorum and subsp. funduliforme, and they differ molecularly, morphologically, biochemically and in virulence. Previous studies have shown that the outer membrane proteins (OMP) of F. necrophorum subsp. necrophorum are important for its successful binding to immobilized bovine adrenal gland capillary endothelial (EJG) cells. In this study, a 42.4 kDa OMP of F. necrophorum subsp. necrophorum with the highest binding capacity to EJG cells was characterized. The gene was cloned into pFLAG-CTS vector and the proteins were subsequently expressed on the surface of E. coli BL21 DE3 cells. When E. coli carrying the recombinant plasmid (SM 2013) was induced using IPTG, there was significant enhancement in the binding to immobilized EJG cells compared to both uninduced SM 2013 and the E. coli carrying control vector only. When fixed EJG cells were incubated with purified native OMP, SM 2013 showed lowered levels of binding, compared to the uninduced SM 2013 and the E. coli carrying control vector only. Pre-incubation of induced SM 2013 with polyclonal antibodies made against the OMP reduced the binding to immobilized EJG cells to uninduced SM 2013 levels. This gain of function by recombinant E. coli confirms the ability of this protein to act as an adhesion to help binding of F. necrophorum subsp. necrophorum to host cells.

Comparison of Mannheimia haemolytica isolates from an outbreak of bovine respiratory disease.

The objective of this study was to determine the clonal relatedness of Mannheimia haemolytica isolates responsible for an outbreak of bovine respiratory disease in a commercial feedlot. The isolates were obtained from the lungs of 21 calves with fatal pneumonia that were part of a group of 206 total calves. All isolates were serotyped and analyzed by pulsed-field gel electrophoresis (PFGE) and for antibiotic sensitivity patterns. ELISA and immunoblotting assays were performed to compare serum antibody levels to M. haemolytica antigens in calves with fatal pneumonia to those calves that survived the outbreak. Isolates were categorized into 14 different PFGE groups based on 90% similarity. Two Group D isolates (1 and 6), and 3 Group H isolates (14, 15, and 16) were characterized as 100% similar. Antimicrobial susceptibility profiles defined 8 groups based on differences in patterns of resistance between isolates. The two 100% similar isolates from PFGE Group D were both in susceptibility Group 1. All but isolate 14 from PFGE Group H (3, 15, 16, and 19) were in susceptibility Group 4a. Serum antibody levels to M. haemolytica antigens in the dead calves were not different than the antibody levels in the 185 calves that survived the outbreak. Immunoblots of selected isolates from each of the PFGE groups demonstrated only minimal differences in antigenic profiles between strains when reacted with serum from calves that either died from or survived the outbreak. Based on the characteristics of these isolates, multiple strains of M. haemolytica were responsible for fatal pneumonia during this outbreak.

Alpha 1-antitrypsin serum levels in widespread bronchiectasis.

This study found significantly higher serum levels of alpha 1-antitrypsin (alpha 1-AT) in 35 patients with widespread bronchiectasis compared with healthy controls. The results are in contradiction with a previous study and four case reports which found an association between alpha 1-AT deficiency and bronchiectasis. However, the validity of the association has been questioned in the literature on the grounds that most of the patients in those reports had other possible aetiologies for their bronchiectasis. We believe the raised level of alpha 1-AT in our patients represents a non-specific acute phase response to bronchial infection. Further studies are needed to clarify whether bronchiectasis, like emphysema, can be a manifestation of alpha 1-AT deficiency.

Septicaemia caused by Vibrio vulnificus.

Vibrio vulnificus is an uncommon cause of septicaemia. A few reports suggest that patients with chronic liver disease are more susceptible. We report two cases of septicaemia caused by this organism and emphasise the need for early empirical therapy.

The "lung shift" in treated schistosomiasis. Bronchoalveolar lavage evidence of eosinophilic pneumonia.

There is conflicting and incomplete information in the literature on the pulmonary reaction which can occur following treatment of schistosomiasis. We examined the pulmonary function, bronchoalveolar lavage profile, and lung histopathology of a patient with pneumonia and peripheral eosinophilia following oxaminquine chemotherapy for intestinal Schistosoma mansoni infection. Spirometry revealed restrictive rather than obstructive impairment, and lavage showed eosinophil prominence which was also seen in the interstitial and alveolar-filling process in transbronchial biopsies.