Risk factors associated with surgical site infection and the development of short-term complications in macaques undergoing indwelling vascular access port placement

BACKGROUND: Risk factors associated with surgical site infection (SSI) and the development of short-term complications in macaques undergoing vascular access port (VAP) placement are evaluated in this study. METHODS: Records from 80 macaques with VAPs were retrospectively reviewed. Logistic regression was used to identify factors associated with short-term post-operative complications. RESULTS: The primary outcome was SSI, which occurred in 21.6% (52.6% in the first 12 months vs. 13% thereafter) of procedures. SSI was associated with major secondary complications including VAP removal (11.4%), wound dehiscence (5.7%), and mechanical catheter occlusion (5.7%). In multivariate modeling, only surgical program progress was a statistically significant predictor of SSI, while animal compliance had a slightly protective effect. CONCLUSIONS: Vascular access ports have a moderate risk of complications, provided the surgical program optimizes best practices. Under complex experimental conditions, VAPs represent an important refinement, both improving animals' overall well-being and environment and reducing stress.     

Cryptosporidium parvum and Giardia lamblia Recovered from Flies on a Cattle Farm and in a Landfill

Filth flies associated with a cattle barn and a municipal landfill were tested positive by combined immunofluorescent antibody and fluorescent in situ hybridization for Cryptosporidium parvum and Giardia lamblia on their exoskeletons and in their guts. More pathogens were carried by flies from the cattle barn than from the landfill; 81% of C. parvum and 84% of G. lamblia pathogens were presumptively viable.     

Value of antigen and antibody detection,and blood evaluation parameters in diagnosis of avian invasive aspergillosis

The applicability of ELISA detection of circulating Aspergillus spp. antigen (Ag) and systemic antibody (Ab) of IgG class, and the blood parameter values were evaluated for diagnosis of invasive aspergillosis in Aspergillus spp.-challenged Peking ducks (Anas platyrhynchos). The protective role of Aspergillus spp. IgG was evaluated in Cape shelducks (Tadorna cana) immunized with Aspergillus spp. Ag. Challenged but non-immunized A. platyrhynchos developed invasive aspergillosis on day 21 as demonstrated histopathologically by the presence of fungal microgranuloma in air sacs and lung tissue, with serum antigenemia fluctuating from 65 to 270 ng of 55-kD basic protein Ag per ml. Immunized A. platyrhynchos did not demonstrate Aspergillus spp. serum antigenemia but did show rare histopathological changes in some air sacs associated with fungal inflammation. Although the differences between immunized and non-immunized T. cana in blood evaluation parameters did not differ significantly, immunized birds mounted high Aspergillus spp.-specific IgG titer. There was no correlation between the blood parameter values and post-immunization timepoints in T. cana and in A. platyrhynchos. Intramuscular immunization with Aspergillus spp. mycelial phase cultures Ag provided protection against the pathogens. The lack of relations between blood parameter values and increasing Aspergillus spp. IgG titers (in T. cana and A. platyrhynchos) indicate low applicability of these parameters in evaluation of a bird Aspergillus spp. status. Detection of circulating 55-kDa Aspergillus spp. Ag has high early predictive values for invasive aspergillosis in birds. This revised version was published online in August 2006 with corrections to the Cover Date.     

Gaseous disinfection of Cryptosporidium parvum oocysts.

Purified oocysts of Cryptosporidium parvum suspended in approximately 400 microliters of phosphate-buffered saline or deionized water in microcentrifuge tubes were exposed at 21 to 23 degrees C for 24 h to a saturated atmosphere of ammonia, carbon monoxide, ethylene oxide, formaldehyde, or methyl bromide gas. Controls were exposed to air. Oocysts in each tube were then rinsed and resuspended in fresh, deionized water, and 1 million oocysts exposed to each gas were orally administered to each of three to six neonatal BALB/c mice in replicate groups. Histologic sections of ileum, cecum, and colon tissues taken from each mouse 72 h after oral administration of oocysts were examined microscopically to determine if infection had been established. All 15 mice given oocysts exposed to carbon monoxide had numerous developmental stages of cryptosporidium in all three intestinal segments. Of 10 mice given oocysts exposed to formaldehyde, 6 had a few developmental stages of cryptosporidium in the ileum. No mice given oocysts exposed to ammonia, ethylene oxide, or methyl bromide were found to be infected. These findings indicate the efficacy of these low-molecular-weight gases (ammonia, ethylene oxide, and methyl bromide) as potential disinfectants for C. parvum oocysts where soil, rooms, buildings, tools, or instruments might be contaminated.     

Viability and infectivity of Cryptosporidium parvum oocysts are retained upon intestinal passage through a refractory avian host.

Six Cryptosporidium-free Peking ducks (Anas platyrhynchos) were each orally inoculated with 2.0 x 10(6) Cryptosporidium parvum oocysts infectious to neonatal BALB/c mice. Histological examination of the stomachs jejunums, ilea, ceca, cloacae, larynges, tracheae, and lungs of the ducks euthanized on day 7 postinoculation (p.i.) revealed no life-cycle stages of C. parvum. However, inoculum-derived oocysts extracted from duck feces established severe infection in eight neonatal BALB/c mice (inoculum dose, 2.5 x 10(5) per mouse). On the basis of acid-fast stained direct wet smears, 73% of the oocysts in duck feces were intact (27% were oocyst shells), and their morphological features conformed to those of viable and infectious oocysts of the original inoculum. The fluorescence scores of the inoculated oocysts, obtained by use of the MERIFLUOR test, were identical to those obtained for the feces-recovered oocysts (the majority were 3+ to 4+). The dynamics of oocyst shedding showed that the birds released a significantly higher number of intact oocysts than the oocyst shells (P < 0.01). The number of intact oocysts shed (87%) during the first 2 days p.i. was significantly higher than the number shed during the remaining 5 days p.i. (P < 0.01) and significantly decreased from day 1 to day 2 p.i. (P < 0.01). The number of oocyst shells shed during 7 days p.i. did not vary significantly (P > 0.05). The retention of infectivity of C. parvum oocysts after intestinal passage through an aquatic bird has serious epidemiological and epizootiological implications. Waterfowl may serve as mechanical vectors for the waterborne oocysts and may enhance contamination of surface waters with C. parvum. As the concentration of Cryptosporidium oocysts in source waters is attributable to watershed management practices, the watershed protection program should consider waterfowl as a potential factor enhancing contamination of the source water with C. parvum.     

Quantitative assessment of contamination of fresh food produce of various retail types by human-virulent microsporidian spores

This study demonstrated that fresh food produce, such as berries, sprouts, and green-leafed vegetables, sold at the retail level can contain potentially viable microsporidian spores of human-virulent species, such as Enterocytozoon bieneusi, Encephalitozoon intestinalis, and Encephalitozoon cuniculi, at quantities representing a threat of food-borne infection.     

Maximizing recovery and detection of Cryptosporidium parvum oocysts from spiked eastern oyster (Crassostrea virginica) tissue samples

Numerous studies have documented the presence of Cryptosporidium parvum, an anthropozoonotic enteric parasite, in molluscan shellfish harvested for commercial purposes. Getting accurate estimates of Cryptosporidium contamination levels in molluscan shellfish is difficult because recovery efficiencies are dependent on the isolation method used. Such estimates are important for determining the human health risks posed by consumption of contaminated shellfish. In the present study, oocyst recovery was compared for multiple methods used to isolate Cryptosporidium parvum oocysts from oysters (Crassostrea virginica) after exposure to contaminated water for 24 h. The immunomagnetic separation (IMS) and immunofluorescent antibody procedures from Environmental Protection Agency method 1623 were adapted for these purposes. Recovery efficiencies for the different methods were also determined using oyster tissue homogenate and hemolymph spiked with oocysts. There were significant differences in recovery efficiency among the different treatment groups (P < 0.05). We observed the highest recovery efficiency (i.e., 51%) from spiked samples when hemolymph was kept separate during the homogenization of the whole oyster meat but was then added to the pellet following diethyl ether extraction of the homogenate, prior to IMS. Using this processing method, as few as 10 oocysts could be detected in a spiked homogenate sample by nested PCR. In the absence of water quality indicators that correlate with Cryptosporidium contamination levels, assessment of shellfish safety may rely on accurate quantification of oocyst loads, necessitating the use of processing methods that maximize oocyst recovery. The results from this study have important implications for regulatory agencies charged with determining the safety of molluscan shellfish for human consumption.     

Urban Feral Pigeons (Columba livia) as a Source for Air- and Waterborne Contamination with Enterocytozoon bieneusi Spores

This study demonstrated that a person with 30 min of occupational or nonoccupational exposure to urban feral pigeons, such as exposure through the cleaning of surfaces contaminated with pigeon excrement, could inhale approximately 3.5 × 10³ Enterocytozoon bieneusi spores and that 1.3 × 10³ spores could be inhaled by a nearby person.     

(4-Carboxamido)phenylalanine is a surrogate for tyrosine in opioid receptor peptide ligands

(S)-4-(Carboxamido)phenylalanine (Cpa) is examined as a bioisosteric replacement for the terminal tyrosine (Tyr) residue in a variety of known peptide ligands for the mu, delta and kappa opioid receptors. The Cpa-containing peptides, assayed against cloned human opioid receptors, display comparable binding affinity (Ki), and agonist potency (EC50) to the parent ligands at the three receptors. Cpa analogs of delta selective peptides show an increase in delta selectivity relative to the mu receptor. Cpa is the first example of an amino acid that acts as a surrogate for Tyr in opioid peptide ligands, challenging the long-standing belief that a phenolic residue is required for high affinity binding.     

Survival of <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> in Wilted and Additive-Treated Grass Silage

Grass was field-dried to 3 different dry matter (DM) levels (200, 430 and 540 g/kg) and inoculated with 10⁶–10⁷ cfu/g of a Listeria monocytogenes strain sharing a phagovar occasionally involved in food-borne outbreaks of listeriosis. Formic acid (3 ml/kg) or lactic acid bacteria (8·10⁵/g) with cellulolytic enzymes were applied only to forages with low and intermediate DM levels. Forages were ensiled in laboratory silos (1700 ml) and were stored at 25°C for 30 or 90 days. After 90 days of storage, L. monocytogenes could not be detected in any silo, except one with the high dry matter grass without additive. After 30 days of storage, between 10² and 10⁶ cfu L. monocytogenes/g silage were isolated from the untreated silages. Increasing the DM content from 200 to 540 g/kg did not reduce listeria counts possibly because of the lower production of fermentation acids (higher pH). In silages treated with additives, counts of L. monocytogenes were always lower than in silages without additive. In wet silages (DM 200 g/kg) both additives were effective, but in the wilted silages (DM 430 g/kg) only the bacterial additive reduced listeria counts below detection level. Listeria counts were highly correlated to silage pH (r = 0.92), the concentration of lactic acid (r = -0.80) and the pooled amount of undissociated acids (r = -0.83).