Camel Streptococcus agalactiae populations are associated with specific disease complexes and acquired the tetracycline resistance gene tetM via a Tn916-like element

Camels are the most valuable livestock species in the Horn of Africa and play a pivotal role in the nutritional sustainability for millions of people. Their health status is therefore of utmost importance for the people living in this region. Streptococcus agalactiae, a Group B Streptococcus (GBS), is an important camel pathogen. Here we present the first epidemiological study based on genetic and phenotypic data from African camel derived GBS. Ninety-two GBS were characterized using multilocus sequence typing (MLST), capsular polysaccharide typing and in vitro antimicrobial susceptibility testing. We analysed the GBS using Bayesian linkage, phylogenetic and minimum spanning tree analyses and compared them with human GBS from East Africa in order to investigate the level of genetic exchange between GBS populations in the region. Camel GBS sequence types (STs) were distinct from other STs reported so far. We mapped specific STs and capsular types to major disease complexes caused by GBS. Widespread resistance (34%) to tetracycline was associated with acquisition of the tetM gene that is carried on a Tn916-like element, and observed primarily among GBS isolated from mastitis. The presence of tetM within different MLST clades suggests acquisition on multiple occasions. Wound infections and mastitis in camels associated with GBS are widespread and should ideally be treated with antimicrobials other than tetracycline in East Africa.     

Impact of agronomic practices on populations of Fusarium and other fungi in cereal and noncereal crop residues on the Canadian Prairies

Fusarium head blight (FHB) is an important disease which has been causing damage to wheat and barley crops in western Canada. Because crop residues are an important source of inoculum, it is important to know the ability of Fusarium spp. to colonize and survive in different residue types, and how their populations might be affected by agronomic practices. Sampling of residue types on producers’ fields for quantification of Fusarium and other fungi was conducted in 2000–2001 in eastern Saskatchewan. Fusarium spp. were isolated from most fields, whereas their mean percentage isolation (MPI) was over 50% for cereal and pulse residues, and under 30% for oilseed residues. The most common Fusarium, F. avenaceum, had a higher MPI in pulse and flax (45–48%) than in cereal or canola (10–22%) residues. This was followed by F. equiseti, F. acuminatum, F. graminearum, F. culmorum and F. poae which were isolated from all, or most, residue types. Factors affecting Fusarium abundance in residues included the current crop, cropping history, and tillage system. In cereal residues, the MPI of F. avenaceum was higher when the current crop was another cereal (24%) versus a noncereal (4–8%). When the current crop was another cereal, the lowest MPI of F. avenaceum and F. culmorum occurred when the field had been in summerfallow (SF) two years previous (F. avenaceum: 17% for SF, 28% for a crop; F. culmorum: 1% for SF, 4% for a crop); in contrast, F. equiseti and Cochliobolus sativus were most common in residues of cereal crops preceded by SF (F. equiseti: 16% for SF, 10% for a crop; C. sativus: 22% for SF, 13% for a crop). The MPI of F. graminearum was higher when the crop two years previous was an oilseed (7%) versus a cereal (4%). In regards to tillage effects, when the current crop was a cereal, the MPI of F. avenaceum was higher under minimum (MT) and zero tillage (ZT) (22–37%) than conventional tillage (CT) (15%), that of F. graminearum was lowest under ZT (3% for ZT, 7–11% for CT-MT), whereas that of C. sativus was highest under CT (27% for CT, 6–11% for MT-ZT). Under ZT, previous glyphosate applications were correlated positively with F. avenaceum and negatively with F. equiseti and C. sativus. These observations generally agreed with results from previous FHB and root rot studies of wheat and barley in the same region. Percentage isolation of F. avenaceum from noncereal and of F. graminearum from cereal residues were positively correlated with FHB severity and percentage Fusarium-damaged kernels of barley and wheat caused by the same fungi.     

The Effect of Knotting Method on the Structural Properties of Large Diameter Nonabsorbable Monofilament Sutures

OBJECTIVE: To evaluate the effect of knotting method on the mechanical properties of large diameter nonabsorbable monofilament suture materials. STUDY DESIGN: In vitro mechanical evaluation. METHODS: A conventional square knot was compared with the surgeon's knot, sliding half-hitch, and clamped square knot. Knotted suture loops were created in a uniform manner and acutely tensioned to failure (20 mm/min loading rate; n = 20 per knot type for each material). Stiffness, yield, and failure characteristics of USP #2 nylon, #2 polybutester, #2 polypropylene, 27 kg test monofilament nylon fishing line, and 27 kg nylon leader material were evaluated. RESULTS: Compared with a conventional square knot, a surgeon's knot decreased stiffness for #2 polypropylene, 27 kg fishing line, and 27 kg leader (P < .05). A sliding half-hitch weakened all materials except 27 kg leader (P < .05). Clamping the first throw of a square knot increased the stiffness of 27 kg leader loops (P < .05). CONCLUSIONS: Based on clinically relevant parameters (stiffness and yield), knotting method had no effect on #2 nylon and #2 polybutester. The surgeon's knot is not recommended for #2 polypropylene and 27 kg fishing line and leader material. A sliding half-hitch decreased the yield of leader material. Clamping the first throw of a square knot had no adverse effects on acute properties of tested materials; it increased the stiffness for leader material. CLINICAL RELEVANCE: Knotting method does influence the structural properties of suture materials and should be considered when tying knots under tension.     

Comparison of autogenous cancellous bone grafts obtained from the sternum and proximal portion of the tibia of llamas.

OBJECTIVE: To describe the anatomy of the sternum in llamas, define the surgical approach to the sternum for collection of cancellous bone graft tissue, and compare the histologic appearance of graft tissue obtained from the sternum with that obtained from the proximal portion of the tibia. DESIGN: Prospective study. ANIMALS: 12 llamas, 3 to 19 years old, that had been submitted for necropsy. PROCEDURE: Radiographs were taken of the sternum and left tibia of the llamas. Measurements of the sternum were determined from the radiographs and adjusted for magnification. Sternebrae volumes were estimated from these measurements. Anatomic dissections to the center of the fourth sternebra and the proximal portion of the tibia were made, and a surgical approach to the sternum was developed. Cancellous graft tissue was obtained from each site and submitted for histologic evaluation. RESULTS: Sternebrae 3, 4, and 5 were significantly larger in volume than the other sternebrae. The ventral aspect of the fourth sternebra was readily accessed for removal of graft tissue by making a 6-cm-long ventral midline incision centered 17 cm craniad to the xipnoid. Mean soft tissue thickness overlying the ventral aspect of the fourth sternebra was 3.1 cm. More tissue was obtained from the sternal (mean, 9.11 g) than from the tibial (mean, 5.16 g) sites. Sternal graft tissue consisted of trabecular bone spicules with predominantly hematopoietic marrow, whereas tibial tissue consisted of trabecular bone spicules with only fatty marrow. CONCLUSIONS AND CLINICAL RELEVANCE: The fourth sternebra in llamas is readily accessible for obtaining autogenous cancellous bone graft tissue that consists of predominantly hematopoietic marrow.     

Application of the polymerase chain reaction to detect fowl adenoviruses.

The possibility of using the polymerase chain reaction (PCR) for the detection of fowl adenoviruses (FAdV) was tested. The optimal reaction parameters were evaluated and defined for purified genomic DNA of type 8 fowl adenovirus (FAdV-8), and then the same conditions were applied for nucleic acid extracted from infected cells. One hundred picograms of purified viral DNA, or 250 FAdV-8-infected cells, were detected by ethidium bromide staining of the PCR products in agarose gels. The sensitivity was increased to 10 pg purified viral DNA, or 25 infected cells, when the PCR products were hybridized with a specific labeled probe. Several field isolates of FAdV and the CELO virus (FAdV serotype 1) could be amplified by the same primers and conditions, but the size of the amplicons was smaller than that for the FAdV-8 PCR product. Other avian viruses and uninfected cell cultures tested negative.     

Studien zur Bekämpfung von Phytophthora ramorum an Rhododendron im Rahmen der Entwicklung eines Behandlungskonzeptes für Park- und Gartenanlagen

In this study dealing with the development of management strategies for P. ramorum in Rhododendron stands several plant protection and fertilizer products were tested for their suitability to control this pathogen on Rhododendron. Tests were conducted on young potted plants and abscised leaves, using the following products: phosphite (Nutri-Phite^® PK), copper hydroxide (Cuprozin^® liquid), Bacillus subtilis (Serenade^®), a mycorrhizal preparation, and a product based on ‘effective microorganisms’ (EMa). Although transmission of the pathogen from infected to healthy plants was successfully inhibited by phosphite, Cu hydroxide and B. subtilis, subsequent tests showed that only phosphite and Cu hydroxide had a significant effect on disease development. All other preparations based on antagonistic or growth promoting microorganisms had no preventive or curative effect. While B. subtilis tended to increase disease symptoms, the remaining products caused a slight reduction of disease severity only. In contrast, phosphite and Cu hydroxide almost completely inhibited infection by P. ramorum. Therefore, in field situations, the use of the ecologically safe, systemic phosphite against P. ramorum in Rhododendron stands appears to be reasonable and advisable. Along with other supporting measures within the framework of a management strategy, this will allow to prevent or slow down further spread of the disease.     

In Vitro Mechanical Comparison of 2.0 and 2.4 Limited‐Contact Dynamic Compression Plates and 2.0 Dynamic Compression Plates of Different Thicknesses

Objective: To compare the bending structural stiffness and bending strength of thick and thin 2.4 mm limited contact dynamic compression plates (2.4 LC‐DCP), 2.0 mm LC‐DCP (2.0 LC‐DCP), and 2.0 dynamic compression plates (2.0 DCP). Study Design: In vitro mechanical study. Methods: Two thicknesses of 2.4 LC‐DCP, 2.0 LC‐DCP, and 2.0 DCP stainless‐steel plates were tested in 4‐point bending. Data were collected during bending until implants plastically deformed. Bending structural stiffness and bending strength were determined from load displacement curves. Mechanical properties were compared between plates and the effects of plate type, size, and thickness on stiffness and strength were assessed using ANOVA. Results: The thick 2.4 LC‐DCP implant was the stiffest and strongest; the thin 2.0 DCP implant was most compliant and weakest. Larger sized plates, thicker plates, and limited contact design of plates enhanced stiffness and strength. For the plates studied, plate size had a larger effect than plate type or thickness on stiffness and strength. Conclusion: Increasing the size (width) and thickness of plates increases both the bending structural stiffness and strength. For the plates studied, LC‐DCP implants were stiffer and stronger than DCP implants. Clinical Relevance: Plate bending structural stiffness and strength can be most effectively enhanced by using a larger sized plate, but gains can also be achieved by using a thicker plate and/or an LC‐DCP instead of a DCP implant when possible.