Multicenter Evaluation of the Simplexa VZV Direct Assay for Detection of Varicella-Zoster Virus in Cerebrospinal Fluid and Lesion-Swab Specimens.

Varicella-zoster virus (VZV) is the etiologic agent of varicella (chickenpox) and herpes zoster (shingles) infections commonly involving skin, mucous membranes, and less frequently the central nervous system. Traditional methods for the laboratory diagnosis of these infections are time-consuming, labor-intensive, and often insensitive. As such, these tests are being replaced by more sensitive and rapid molecular methods. This study evaluated the performance of two different molecular assays, the Simplexa VZV Direct and Simplexa VZV Swab Direct, to detect VZV DNA in cerebrospinal fluid (CSF) and lesion-swab specimens, respectively. The Simplexa VZV Direct and Simplexa VZV Swab Direct assays were compared against individual composite reference methods that varied depending on the sample cohort examined. A total of 883 CSF and 452 cutaneous and mucocutaneous prospective, retrospective, and contrived specimens were evaluated in this multicenter study. The results of this study showed that the Simplexa assays demonstrated near perfect agreement (k = 0.98) compared to the composite reference methods for the detection of VZV in CSF and lesion swab specimens. A further comparison between the standard of care molecular assays employed at the site of specimen collection and the Simplexa assays demonstrated excellent agreement (k = 1.0). The Simplexa assays offer rapid and reliable alternatives for the detection of VZV in certain clinical specimens without the need for nucleic acid extraction.

Titration of supplemental Bacillus subtilis subsp. subtilis American Type Culture Collection PTA-125135 to broiler chickens fed diets of 2 different metabolizable energy concentrations.

Bacillus subtilis subsp. subtilis American Type Culture Collection deposit number PTA-125135 has recently been studied by our laboratory as a potential probiotic strain for avian species. The objective of the present study was to evaluate growth performance and feed efficiency in broiler chickens in response to a dose titration of the Bacillus strain in feed. In addition to a nonsupplemented control, Bacillus spores were supplemented into broiler chicken diets at 4 levels, which were 8.1 × 104, 1.6 × 105, 2.4 × 105, and 3.2 × 105 CFU per g of feed. The titration was applied to two different dietary regimes of standard or low metabolizable energy (ME), which differed in ME by 22, 56, and 110 kcal/kg in starter, grower, and finisher dietary phases, respectively. All diets contained 249 g per metric ton of a previously patented synbiotic feed additive. Performance data were collected at day 14, 26, and 40 of age, and the effects of Bacillus and ME treatments were evaluated by factorial ANOVA. Treatment group means were further examined for significant (P < 0.05) pairwise differences among treatments and for significant (P < 0.05) linear and quadratic effects. At day 14 of age, significant linear effects for decreased feed conversion ratio (FCR) with higher CFU of Bacillus supplementation were observed within the standard ME diet. At day 26, a linear trend was observed for increased mortality with increased dose within the standard ME diet only. Bacillus supplementation at day 26 also significantly affected FCR and mortality-adjusted FCR, where supplementation with 3.2 × 105 CFU per g feed produced lower FCR and mortality-adjusted FCR than supplementation with 1.6 × 105 CFU per g feed. We conclude from linear effects related to feed efficiency observed at day 14 and from the significant separation of Bacillus treatment means within the titrated range of supplementation at day 26 that further evaluation for effects on performance should be made of doses at 2.4 × 105, 3.2 × 105, and greater CFU per g in feed.

Effect of Bacillus subtilis DSM 32315 on the intestinal structural integrity and growth performance of broiler chickens under necrotic enteritis challenge.

The effect of dietary inclusion of Bacillus subtilis DSM 32315 on the intestinal health and growth performance of Cobb 500 male broilers subjected to a Clostridium perfringens-induced necrotic enteritis (NE) challenge was determined in 2 experiments. In experiment 1, chicks were randomly assigned to 4 treatments of 10 replicate/treatment. In experiment 2, chicks were randomly assigned to 4 treatments of 12 replicates/treatment. The experimental treatments were non-infected, non-supplemented control, infected, non-supplemented control (IC), infected + Bacillus subtilis DSM 32315 (B. subtilis DSM 32315), infected + bacitracin methylene disalicylate (BMD). In both experiments, NE was induced by oral inoculation of toxin producing C. perfringens on 3 consecutive days between 17 and 20 D of age, following exposure of birds to pre-disposing conditions. At day 28 (experiment 1), broilers fed diets with B. subtilis DSM 32315 exhibited a significantly higher body weight, lower mortality, and intestinal NE lesion score, compared to the IC treatment. At day 42 (experiment 2), B. subtilis DSM 32315 supplementation significantly improved BW, feed conversion ratio, production efficiency factor, NE lesion score, and mortality, compared to IC treatment. The effect of B. subtilis DSM 32315 on intestinal integrity of NE challenged chickens was evaluated with histomorphometry. A significantly shallower crypt depth and higher villus height to crypt depth ratio were observed in the mid-intestine of birds belonging to the B. subtilis DSM 32315 group, compared to the IC group. Furthermore, B. subtilis DSM 32315 supplementation significantly reduced the enteritis index associated with NE. In both experiments, the effect of B. subtilis DSM 32315 on the phenotypic measurements of NE and performance was comparable to the effect observed with BMD supplementation. In conclusion, supplementation of the direct fed microbial strain B. subtilis DSM 32315 can ameliorate the pathology and performance detriments associated with NE.

Multicenter Evaluation of NeuMoDx Group B Streptococcus Assay on the NeuMoDx 288 Molecular System.

Group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis in developed countries. Recommendations for antepartum GBS detection include enriched culture with several options for identifying GBS, some of which are time-consuming. To reduce the time for identification and determination of the maternal GBS colonization status, rapid nucleic acid amplification technologies have been developed and commercialized. For rapid detection of GBS, a three-site clinical study was conducted to evaluate the NeuMoDx GBS assay, a real-time PCR test performed for vaginal/rectal swab specimens in Lim broth enrichment culture on the NeuMoDx 288 molecular system (NeuMoDx system); these data were used to a support 510(k) submission. A total of 1,250 eligible remnant samples were prospectively enrolled and tested during the study. The results of the PCR assay were compared to the results of the Centers for Disease Control and Prevention (CDC)-recommended enriched-culture method, which served as the gold standard reference method for the study. The NeuMoDx GBS assay results yielded a sensitivity of 96.9% (95% confidence interval [CI] = 94.1 to 98.4), specificity of 96.0% (95% CI = 94.6 to 97.1), and a total agreement with the reference method of 96.2% (95% CI = 93.8 to 98.3). NeuMoDx GBS assay results were also compared to results obtained using the BD MAX GBS assay on the BD MAX system. The two systems demonstrated a total percent agreement of 98.0% (95% CI = 95.5 to 100.0). The performance of the NeuMoDx GBS assay implemented on the NeuMoDx system compared favorably to the CDC enriched-culture method and to the BD MAX GBS assay.

Avi-Lution® supplemented at 1.0 or 2.0 g/kg in feed improves the growth performance of broiler chickens during challenge with bacitracin-resistant Clostridium perfringens.

Avi-Lution® is a defined, patented, synbiotic product containing Saccharomyces cerevisiae, Enterococcus faecium, and Bacillus spp. Broiler chickens (n = 1,250) were experimentally treated as uninoculated controls (uCon), inoculated controls (iCon) with Clostridium perfringens, or inoculated and treated with bacitracin methylene disalicylate (BMD) at 55 mg/kg as an infected/treated control or Avi-Lution® at 1.0 (AvL1) or 2.0 (AvL2) g/kg in feed for 42 d. Each treatment was applied to 10 replicate pens of 25 straight-run, newly hatched chicks. Pens treated with AvL1, AvL2, or BMD showed improved growth, feed efficiency, or mortality from necrotic enteritis compared with iCon pens at d 14, 28, and 42. No differences in these measurements, however, were observed between pens treated with AvL1 and AvL2, which suggests that Avi-Lution® was effective at 1.0 g/kg in feed. Despite improved performance, BMD, AvL1, and AvL2 treatments did not decrease the severity of intestinal lesion scores through 42 d of age compared with the infected control. These results demonstrate that Avi-Lution® improved growth performance and feed conversion rates in broilers challenged with Clostridium perfringens despite no difference in severity of intestinal lesion scores.

Pulmonary injury after combined exposures to low-dose low-LET radiation and fungal spores.

Exposure to infectious microbes is a likely confounder after a nuclear terrorism event. In combination with radiation, morbidity and mortality from an infection may increase significantly. Pulmonary damage after low-dose low-LET irradiation is characterized by an initial diffuse alveolar inflammation. By contrast, inhaled fungal spores produce localized damage around pulmonary bronchioles. In the present study, we assessed lung injury in C57BL/6 mice after combined exposures to whole-body X radiation and inhaled fungal spores. Either animals were exposed to Aspergillus spores and immediately irradiated with 2 Gy, or the inoculation and irradiation were separated by 8 weeks. Pulmonary injury was assessed at 24 and 48 h and 1, 2, 4, 8, and 24 weeks later using standard H&E-stained sections and compared with sham-treated age-matched controls. Immunohistochemistry for invasive inflammatory cells (macrophages, neutrophils and B and T lymphocytes) was performed. A semi-quantitative assessment of pulmonary injury was made using three distinct parameters: local infiltration of inflammatory cells, diffuse inflammation, and thickening and distortion of alveolar architecture. Radiation-induced changes in lung architecture were most evident during the first 2 weeks postexposure. Fungal changes were seen over the first 4 weeks. Simultaneous combined exposures significantly increased the duration of acute pulmonary damage up to 24 weeks (P < 0.01). In contrast, administration of the fungus 8 weeks after irradiation did not produce enhanced levels of acute pulmonary damage. These data imply that the inhalation of fungal spores at the time of a radiation exposure alters the susceptibility of the lungs to radiation-induced injury.

A simple quantitative method for assessing pulmonary damage after x irradiation.

Pulmonary damage after radiotherapy is typically characterized by an initial alveolar inflammation (pneumonitis) followed by chronic fibrosis. In the present study, changes in lung architecture were measured in the pneumonitis phase after whole-body low-dose X irradiation of C57BL/6 mice. Radiation damage was evaluated at 24 h and 1-8 weeks postirradiation. Three distinct scoring systems were used: ( 1 ) manually evaluating alveolar distortion and infiltration of inflammatory cells into the alveolar space using a continuous numerical scale across an entire lung section, ( 2 ) physically measuring the average thickness of the alveolar septa from multiple representative microscope fields, and ( 3 ) a new rapid automated mathematical algorithm based on image segmentation of alveolar space across an entire section. Each scoring method detected significant changes in alveolar architecture at the earliest times compared with sham-treated controls and gave comparable evaluations of injury. The results from the automated mathematical algorithm correlated significantly with both the manual evaluation method (Spearman's correlation coefficient rho = 0.044) and the direct physical measurement of septa thickness (rho = 0.002). These data demonstrate that evaluating alveolar space by segmentation analysis provides a reliable method for scoring early pulmonary radiation damage that is consistent with more established methodologies but is more rapid and is independent of potential operator and selection bias.

Evaluation of dietary Natustat for control of Histomonas meleagridis in male turkeys on infected litter.

Histomoniasis (histomonosis, infectious enterohepatitis, or blackhead) is a disease of turkeys on litter or range caused by the protozoan Histomonas meleagridis, a parasite of worms, primarily spread in feces, in Heterakis gallinarum (cecal worm) eggs, or in Eisenia foetida (earthworms). In this trial, Natustat (Alltech, Inc., Nicholasville, KY), a proprietary plant-derived product, was used at 1.925 kg/tonne and compared with nitarsone in male hybrid turkey diets to 42 days of age on histomonad infected litter (day 7) from broiler breeders. Infected nonsupplemented and uninfected nonsupplemented control groups were also included. Natustat and nitarsone significantly improved 28- and 42-day feed conversion ratios and lowered 28- and 35-day cecal and liver lesion scores compared with infected nonsupplemented turkeys. The body weight at 42 days was greater in the Natustat and nitarsone supplemented groups than in the infected nonsupplemented group.

The efficacy of TAMUS 2032 in preventing a natural outbreak of colibacillosis in broiler chickens in floor pens.

A 42-d floor pen study was conducted with broiler chickens comparing the effects on bird performance of 12 ppm TAMUS 2032 (also known as BT) and 55 ppm bacitracin methylene disalicyclate (BMD) when fed alone or in combination with 99 ppm monensin (MON). Unmedicated and 99 ppm MON treatments were included in the study design. Beginning on d 22 of study, birds in all 6 treatments were subjected to a modulated house temperature and airflow to mimic conditions conducive to outbreaks of colibacillosis. A natural outbreak of colibacillosis developed beginning on d 27. Primary lesions in dead birds included airsacculitis and pericarditis with occasional findings of perihepatitis. At d 42 of study, means for weight gain in the TAMUS 2032 and TAMUS 2032 + MON treatments were greater in comparison with the unmedicated and BMD treatments, and means for feed conversion for both treatments were improved in comparison with the unmedicated treatment. Mean feed conversion in the TAMUS 2032 + MON treatment was also improved in comparison with BMD treatment. Mortality due to colibacillosis was reduced in the TAMUS 2032 (0.051%), TAMUS 2032 + MON (0.642%), and MON + BMD (1.515%) treatments in comparison with the unmedicated treatment (13.402%) and the BMD treatment (11.159%). The results of improved performance and reduced mortality indicated that 12 ppm TAMUS 2032 was highly efficacious against colibacillosis in growing chickens. The reduced mortality percentages in the MON + BMD treatment indicated that this combination also provided a good level of protection against the natural outbreak of colibacillosis.

Effects of dietary mannan oligosaccharide, bacitracin methylene disalicylate, or both on the live performance and intestinal microbiology of turkeys.

Hybrid male turkeys were fed to 18 wk of age in a completely randomized design with 10 replicate pens (18 birds each) per treatment to compare growth promoters. Four dietary treatments were used: negative control (CON), bacitracin methylene disalicyate (BMD) at 55 mg/kg to 6 wk and 27.5 mg/kg thereafter, mannan oligosaccharide (MOS) at 0.1% to 6 wk and 0.05% thereafter, and BMD and MOS at concentrations listed above. There were 3 toms/m2 (3.59 ft2/tom) on fresh pine shavings inoculated with used litter. A 6-phase feeding program was used, with crumbles the first 3 wk and pellets thereafter. At wk 6 and 18, one bird per pen was killed, and the large intestinal microbial populations, after being frozen, were enumerated (i.e., bifidobacteria, Clostridium perfringens, coliforms, enterococci, Escherichia coli, lactobacilli, and total anerobes). Body weights at wk 18 were as follows: CON, 11.87 kg; BMD, 12.46 kg; MOS: 12.56 kg; and BMD + MOS, 12.79 kg. The BMD and MOS turkeys were (P < 0.05) heavier than CON birds, and those fed the combination were significantly heavier than all other treatments. At wk 18, BMD + MOS feed conversion ratio of 2.66 was significantly lower than CON at 3.00 with BMD and MOS being intermediate (2.83 and 2.79, respectively). Mortality was not affected by treatment. The BMD and MOS each reduced large intestinal concentrations of Clostridium perfringens (log transformed data analysis) at wk 6 but not at wk 18. The BMD or MOS each improved turkey performance, and when used together, exhibited further beneficial effects.

Efficacy of the antimicrobial compound U-82,127 as a growth promoter for growing-finishing pigs.

The antimicrobial compound U-82,127 (Pharmacia & Upjohn, Kalamazoo, MI) is a thiopeptide that belongs to a series of cyclic peptide antibiotics produced by Streptomyces arginensis. It is active mainly against Gram-positive organisms. A study involving 576 growing-finishing pigs was conducted at six locations to assess the efficacy of the growth-promoting compound from approximately 19 to 89 kg BW. The basal diet was an unmedicated corn-soybean meal diet fortified with vitamins and trace minerals and containing 16% CP (.80% lysine) during the growing stage (to 54 kg) followed by 13% CP (.60% lysine) during the finishing stage. Dietary dose concentrations of the antimicrobial compound were 0, 3.3, 6.6, and 9.9 mg/kg. At each location, there were six replications of four pigs (two barrows and two gilts) per pen. Diets and water were available for ad libitum consumption. The antimicrobial was provided in coded bags, and investigators were blind to the treatments. The ADG during the growing stage was improved by all levels of the antimicrobial (P < .04), but only the 6.6 mg/kg level improved ADG during the finishing stage (P < .03). Feed:gain was improved by all concentrations of the antibiotic (P < .01) during the growing stage and by the two lower levels of the drug (P < .06) during the finishing stage. Over the entire study, the antimicrobial compound improved ADG (linear, P < .06) and feed:gain (quadratic, P < .01; minimum feed:gain was at 6.2 mg/kg). The lowest dose with a 90% confidence interval of its predicted value not overlapping with the predicted value of the control was 2.3 mg/kg; thus, the efficacious dose range for improving feed/gain was between 2.3 and 6.2 mg/ kg. Neither death loss nor pig removal from the experiment was affected by treatment. The results indicate that the antimicrobial compound U-82,127 is an effective growth-promoting agent for growing-finishing pigs.

The response of broiler chickens to the addition of bacitracin methylene disalicylate to diets containing salinomycin and roxarsone.

Two experiments were conducted to evaluate the response of broiler chickens to addition of bacitracin methylene disalicylate (BMD) to diets containing salinomycin. In each experiment, five tests were conducted at different locations. In Experiment 1, all diets contained 66 mg salinomycin/kg of diet for the first 42 days and either 0 or 33 mg BMD/kg of diet for the entire 49-day feeding period. In Experiment 2, all diets contained 66 mg salinomycin and 50 mg roxarsone/kg of diet for the first 42 days and either 0, 11, 33, or 55 mg BMD/kg of diet for the entire 49-day feeding period. In Experiment 1, addition of 33 mg BMD/kg of diet significantly (P less than .05) improved body weights and feed utilization. Results were similar in all five tests. In Experiment 2, addition of 11, 33, or 55 mg BMD/kg of diet significantly (P less than .05) increased body weights. In one location the addition of 55 mg BMD/kg of diet resulted in no significant difference in body weight compared with those fed the unsupplemented diet, but in all other locations the response was similar. Addition of 33 or 55 mg BMD/kg of diet resulted in improved (P less than .05) feed utilization when all tests were combined. Feed utilization was not improved in all locations by the addition of BMD.