Subcutaneous Bacteria in Turkey Carcasses

Two methods were employed to quantitate the subcutaneous bacteria in fresh, refrigerated, and frozen turkey carcasses. Relatively few bacteria were detected in the skin-flesh interface and in the flesh as compared with the number of bacteria on the skin surface and in the skin layer. No subcutaneous bacteria were detected in 49% of the skin-flesh interface and flesh samples. The number of bacteria detected in skin samples from carcasses chemically disinfected to kill skin surface bacteria was smaller than that in nondisinfected skin samples. These results indicate that the skin blending method used to quantify microorganisms on poultry carcass skin measures the skin layer flora and that the number of subcutaneous membrane or flesh bacteria measured is not normally large enough to have a significant influence on the results.     

A Note on the Survival of some Bacteria in Different Diluents

The best diluent for four bacterial species was 0·1% (w/v) peptone solution. Tap water containing 0·1% (w/v) sodium thiosulphate was less satisfactory but tap water, tap water treated with charcoal, quarter-strength Ringer's solution, 0·85% (w/v) sodium chloride solution and glass distilled water were all bactericidal to one or more of the test species.     

Faecal indicator bacteria enumeration in beach sand: a comparison study of extraction methods in medium to coarse sands

Aims:  The absence of standardized methods for quantifying faecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal bacteria from sands and recommend a standardized extraction technique.
Methods and Results:  Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts.
Conclusions:  The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types.
Significance and Impact of the Study:  Method standardization will improve the understanding of how sands affect surface water quality.     

The Recovery of Indicator Bacteria on Selective Media

S ummary . The recovery of Pseudomonas aeruginosa, Escherichia coli , and Streptococcus faecalis from aqueous suspending media has been studied with a rich plating medium (trypticase-soy agar) and selective media. Tap water was highly toxic to all strains investigated. Recovery of Ps. aeruginosa was most successful when phosphate buffer was the diluent. Phosphate buffer did not improve the recovery of E. coli. Streptococcus faecalis remained viable when suspended in double distilled water, deionized distilled water or phosphate buffer. Following a lag period all strains grew in 0.1% peptone water or stream water. Injury preventing recovery of viable cells on selective media occurred during suspension in all aqueous media tested, including those which supported growth. These observations suggest difficulties inherent in the interpretation of bacteriological results obtained during surveys of water sources and a need to reduce the selectivity of recovery media against injured cells.     

Comparison of treatments for the in vitro detachment of cellulolytic bacteria from ruminal digesta samples

Four treatments were applied to ruminal digesta samples in a randomized complete block design experiment to evaluate their effect on the extent of detachment of ruminal cellulolytic bacteria. The treatments were: blending with anaerobic dilution solution (ADS), blending with ADS after a 6-h cold incubation, blending with ADS+Tween 80, and blending with ADS +Tween 80 after a 6-h cold incubation. Compared with blending in ADs alone, significant increases (p<0.2) of 10% and 12% in the number of cellulolytic bacteria were observed with the 6-h cold and the 6-h cold plus Tween 80 treatments, respectively. Tween 80 had no effect on the number of cellulolytic bacteria released from ruminal digesta samples irrespective of chilling. It was concluded that these additional treatments afforded little value over blending in buffer alone in detaching cellulolytic bacteria from ruminal digesta.     

Solute effects on Lagenidium giganteum: zoospore motility and bioassay reproducibility

The zoospores of Lagenidium giganteum rapidly lose motility when dispersed in deionized water. Several organic solutes were tested for the ability to prolong zoospore activity. Peptone at 0.2 and 0.05 g/liter was more effective than methionine and glucose, individually or in combination. The use of 0.2 g/liter of peptone as a medium for bioassays of L. giganteum against 3-day-old Aedes aegypti reduced the mean LD₅₀ to 12.9 zoospores/ml as compared to 133 with field water and 124 with deionized water. The use of peptone also dramatically improved the reproducibility of the assays and the goodness of fit of the resultant probit regression lines. The mean χ² values were 7.4 for 0.2 g/liter of peptone, 26.8 for field water, and 47.8 for deionized water. It is suggested that the erratic results obtained from use of deionized water are due to variation in the osmotic stress to which the zoospores were exposed, depending on the amount of debris that is introduced into the assays along with the mosquito larvae.     

Effect of Immobilizing Substances and Salinity on Heavy Metals Availability to Wheat Grown on Sewage Sludge-Contaminated Soil

The objective of the investigation was to evaluate the effect of immobilizing substances and NaCl salinity on the availability of heavy metals: Zn, Cd, Cu, Ni, and Pb to wheat (Triticum aestivum L.). In greenhouse pot experiment, a sewage sludge amended soil was treated with the following immobilizing substances: three clay minerals (Na-bentonite, Ca-bentonite and zeolite), iron oxides (goethite and hematite), and phosphate fertilizers (superphosphate and Novaphos). The pots were planted with wheat and were irrigated either with deionized or saline water containing 1600 mg L^?1 NaCl. Wheat was harvested two times for shoot metal concentrations and biomass measurements. Metal species in soil solution were estimated using the software MINEQL+.

The addition of metal immobilizing substances to the soil significantly decreased metal availability to wheat. The largest reduction in metal bioavailability was found for bentonites. The irrigation with saline water (1600 mg L^?1 NaCl) resulted in a significant increase in metal chloride species (MCl⁺ and MCl₂ ⁰). The highest metal complexation with Cl occurred for Cd, which was about 53% of its total soil solution concentration. The total concentration of Cd (Cd_T) in soil solution increased by 1.6–2.8-fold due to saline water. The NaCl salinity caused a significant increase in uptake and shoot concentration of Cd for two harvests and small but significant increase in shoot Pb concentration for the second harvest. It was concluded that the use of bentonites is the most promising for the reduction of heavy metal availability to plants. Saline water containing 1600 mg L^{? 1} NaCl increased the availability of Cd and Pb to wheat and decreased the efficiency of bentonites to immobilize soluble Cd.     

Epidemic trichodinosis associated with severe epidermal hyperplasia in largemouth bass, Micropterus salmoides, from North Carolina, USA

An epidemic of trichodinosis associated with severe epidermal hyperplasia occurred in adult largemouth bass (Micropterus salmoides) from the Chowan River drainage, North Carolina (USA) in late winter to early spring 2002. Initial reports by anglers of fish with a "jelly-like slime coat" on the skin prompted an electrofishing survey in which about 10% of sampled largemouth bass had a very thick, bluish-white "mucoid layer" on the body and fins. Moderate to heavy infestations of the ciliate Trichodina were detected in wet mounts of skin from five of five fish having the mucoid layer; these fish also had significant gill infestations. An additional two fish with only mild reddening and four asymptomatic fish (no skin lesions) had mild skin infestations but no gill infestations. Two asymptomatic fish had no skin parasites. Four fish with the mucoid layer were necropsied and had extremely severe epidermal hyperplasia on the body and fins. The hyperplasic epidermis had relatively few mucus cells and typically was about 5-10 times thicker than healthy epidermis. The upper four fifths of the epidermis consisted of finely vacuolated, highly flattened, somewhat disorganized epithelial cells. No other significant clinical or histopathologic abnormalities were detected. No systemic infection by pathogenic bacteria was noted. The environmental cause of the epidemic is uncertain but the lesions suggest that some chronic stressor was involved.     

Cutaneous blood flow and water absorption by dehydrated toads

Blood cell flux (BCF) in ventral pelvic skin capillaries was measured in toads, Bufo woodhouseii and Bufo punctatus, using a chamber that allowed hydration behavior and water absorption to be observed concurrently in unrestrained animals. Dehydrated B. woodhouseii and B. punctatus placed on a rehydration solution significantly increased BCF relative to that on a dry surface in less than 2 min. Skin contact with a rehydration solution rather than dehydration alone is the primary stimulus for increased seat patch blood flow. In B. woodhouseii, the water absorption response was initiated after the increase in BCF had started but before maximum BCF was reached. BCF and water uptake across the ventral skin of both species placed on deionized water were not different from those of toads placed on 50 mM NaCl. Similarly, no significant correlation between BCF and rate of water uptake could be observed in dehydrated toads of either species. Angiotensin II (AII) injection in hydrated B. punctatus had no effect on BCF, suggesting that factors other than AII are responsible for the increase in blood flow upon water contact in dehydrated toads.     

Studies on yellow fever vaccine. II--Stability of the reconstituted product

This work evaluated the stability of diluted yellow fever vaccine in order to determine conditions that maintain the minimum of 3 log10 of 17D virus per human dose as required by WHO. The vaccines were held at 0 degrees C or at 37 degrees C and were diluted either with distilled water, with 0.15 M saline or with 0.15 M PBS at pH 5.5, 7.2 and 8.0. In a next step, stabilizer substances such as gelatin and peptone were added to the vaccines. Dilution of the vaccines in distilled water maintained the virus titre for up to three hours at 37 degrees C and this diluent has been adopted for routine use in Brazil.     

Prediction of body composition of live and post-mortem red foxes

A series of measurements (lengths, circumferences, skinfolds, masses and resistance) was taken on 29 red foxes (Vulpes vulpes) of both sexes before and after their death during the autumns of 1994 and 1995. Body composition of each carcass was determined by chemical analysis of homogenized samples of viscera, carcass and skin. Eight multiple regression models were then developed to predict body water, fat, protein, and mineral mass using body measurements as independent variables taken on live or dead animals. All final models were highly significant (P < 0.0001) and included three or four explanatory variables. Adjusted coefficients of determination varied between 0.95 for water mass and 0.81 for mineral mass. The models cover a wide range of conditions as percent body fat in the 29 samples varied between 1.1 and 28.4%. Our models can serve for management or research purposes with live or dead red foxes as they are quick, inexpensive and nondestructive.     

Impact of relative humidity and collection media on mycobacteriophage D29 aerosol

This study was conducted to evaluate the effect of aerosol generation, methods of sampling, storage conditions, and relative humidity on the culturability of the mycobacteriophage D29. The lytic phage D29 can kill Mycobacterium tuberculosis, and the phage aerosol can be treated as a potential tool for tuberculosis treatment. The culturability of D29 was tested using a test chamber designed for the bioaerosols research against three spray liquids (deionized water, phosphate-buffered saline [PBS], and normal saline), four collection media (suspension medium [SM], nutrient broth, PBS, and deionized water), two sampling systems (the all-glass impinger AGI-30 and the Biosampler) and across a range of humidities (20 to 90%). The effect of storage conditions on the culturability of collected sample was also evaluated for the AGI-30 impinger. The results proved that viable phage D29 particles generated by deionized water were approximately 30- and 300-fold higher than PBS and normal saline, respectively. As collection media, SM buffer and nutrient broth were observed to yield a higher number of plaques compared to PBS and deionized water. No difference was observed in collection efficiency between AGI-30 and Biosampler with two detection methods (culture-based technique and real-time PCR). The culturability of collected D29 in SM buffer or nutrient broth can be maintained up to 12 h irrespective of storage temperature. Relative humidity was found to strongly influence airborne D29 culturability which is 2- to 20-fold higher in low humidity (25%) than medium (55%) or high (85%) humidity. This research will help identify the optimal means for the application of D29 aerosol in animal inhalation experiments.     

Accelerating tissue expansion by application of topical papaverine cream

The rate of tissue expansion can be accelerated by papaverine through a special delivery system, according to an early report. Because the delivery system was complex and inconvenient, another means of administrating papaverine was tested to observe the rate of tissue expansion. In this study, 24 miniature pigs were divided equally into three groups. Four 150-ml silicone expanders were implanted into each pig in groups A and C. Four modified rectangular silicone expanders were also implanted into each animal in group B. During the expansion process, 1 g of 2% hydrochloride papaverine cream was applied topically onto the surface of each pig's expanding skin in group A two times daily, and hydrochloride papaverine solution was injected into the outer shell of each modified expander in group B weekly. Group C acted as the control group. The mean sum of the first four times of saline water volume that was injected into the expanders was 142.42 +/- 5.6 ml in group A, 128.72+/-4.8 ml in group B, and 106.38+/-3.28 in group C. There were statistical differences among the three groups. The mean sum of volume saline water that was injected into hind expanders was 137.51 +/- 5.1 ml in group A, 120.35 +/- 3.6 ml in group B, and 102.63 +/- 4.76 ml in group C, and there was a statistical difference among the three groups as well. There was no statistically significant difference in the thickness of fibrous capsules among the three groups. This study shows that the rate of tissue expansion can be accelerated by topical application of papaverine cream, and the rate is better than the rate of tissue expansion induced by the special drug delivery system.     

Monensin-based medium for determination of total gram-negative bacteria and Escherichia coli.

Plate count-monensin-KCl (PMK) agar, for enumeration of both gram-negative bacteria and Escherichia coli, is composed of (per liter) 23.5 g of plate count agar, 35 mg of monensin, 7.5 g of KCl, and 75 mg of 4-methylumbelliferyl-beta-D-glucuronide (MUG). Monensin was added after the medium was sterilized. The diluent of choice for use with PMK agar was 0.1% peptone (pH 6.8); other diluents were unsatisfactory. Gram-negative bacteria (selected for by the ionophore monensin) can be used to judge the general quality or sanitary history of a commodity. E. coli (differentiated by its ability to hydrolyze the fluorogenic compound MUG) can be used to assess the safety of a commodity in regard to the possible presence of enteric pathogens. Pure-culture studies demonstrated that monensin completely inhibited gram-positive bacteria and had little or no effect on gram-negative bacteria. When gram-negative bacteria were injured by one of several methods, a few species (including E. coli) became sensitive to monensin; this sensitivity was completely reversed in most instances by the inclusion of KCl in the medium. When PMK agar was tested with food and environmental samples, 96% of 535 isolates were gram negative; approximately 68% of colonies from nonselective medium were gram negative. PMK agar was more selective than two other media against gram-positive bacteria and was less inhibitory for gram-negative bacteria. However, with water samples, KCl had an inhibitory effect on gram-negative bacteria, and it should therefore be deleted from monensin-containing medium for water analysis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Monensin-based medium for determination of total gram-negative bacteria and Escherichia coli

Plate count-monensin-KCl (PMK) agar, for enumeration of both gram-negative bacteria and Escherichia coli, is composed of (per liter) 23.5 g of plate count agar, 35 mg of monensin, 7.5 g of KCl, and 75 mg of 4-methylumbelliferyl-beta-D-glucuronide (MUG). Monensin was added after the medium was sterilized. The diluent of choice for use with PMK agar was 0.1% peptone (pH 6.8); other diluents were unsatisfactory. Gram-negative bacteria (selected for by the ionophore monensin) can be used to judge the general quality or sanitary history of a commodity. E. coli (differentiated by its ability to hydrolyze the fluorogenic compound MUG) can be used to assess the safety of a commodity in regard to the possible presence of enteric pathogens. Pure-culture studies demonstrated that monensin completely inhibited gram-positive bacteria and had little or no effect on gram-negative bacteria. When gram-negative bacteria were injured by one of several methods, a few species (including E. coli) became sensitive to monensin; this sensitivity was completely reversed in most instances by the inclusion of KCl in the medium. When PMK agar was tested with food and environmental samples, 96% of 535 isolates were gram negative; approximately 68% of colonies from nonselective medium were gram negative. PMK agar was more selective than two other media against gram-positive bacteria and was less inhibitory for gram-negative bacteria. However, with water samples, KCl had an inhibitory effect on gram-negative bacteria, and it should therefore be deleted from monensin-containing medium for water analysis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of Diluent and Relative Humidity on Apparent Viability of Airborne Pasteurella pestis

Airborne Pasteurella pestis (A-1122) at low humidities [20 to 50% relative humidity (RH)] exhibited exponential decay when either 1% peptone or Heart Infusion Broth (HIB) was used as the diluent in the viable assay system. At higher RH values (65 and 87%), however, the 1% peptone diluent adversely affected the viability assay. In contrast, HIB as diluent was remarkably effective in demonstrating a higher number of viable cells in aerosols held at high RH values. Similarly, with HIB as diluent, aerosols were shown to contain viable cells during 90 min of observation; with 1% peptone, viability was not detectable after 20 min in the airborne state.     

A note on the enumeration of manganese-oxidizing bacteria in estuarine water and sediment samples

V ojak , P.W.L., E dwards , C. & J ones , M.V. 1985. A note on the enumeration of manganese-oxidizing bacteria in estuarine water and sediment samples. Journal at Applied Bacteriology 59, 375–379.
Media for the enumeration of manganese-oxidizing bacteria in estuarine water and sediment samples were compared. A peptone/yeast extract medium containing manganese sulphate and 30% (v/v) sea salts solution gave the highest percentage of manganese-oxidizers and high total viable counts. A survey of estuarine (River Tamar) and marine (English Channel) sites indicated that manganese-oxidizing bacteria comprise a significant but variable proportion (11–85%) of the total bacterial count.     

Effect of homogenization procedures on Escherichia coli counts in naturally contaminated cheese

A comparison was made between blending in 2% sodium citrate and stomaching in 0.1% peptone or 0.1% peptone - 1% Tween 80 for the enumeration of Escherichia coli in naturally contaminated cheeses. Statistical analysis of the results from 25 samples of cheese showed that there were no significant differences in recovery by the three methods at the 95% confidence level.     

Saline intake after shifts to water in hamsters and gerbils

In Experiment 1, hamsters and gerbils were given a 24-hr two-bottle test with saline and water for eight days before being placed on a water-only condition for the subsequent four days. On day 13 the saline bottle was returned to the animals and their intake of saline and water was monitored for another six days. Comparisons were made of the animals' intake of saline during the last two pre-withdrawal with that during the first two post-withdrawal days. Saline intake was enhanced in male but not in female gerbils following the 4-day withdrawal period. In contrast, male hamsters showed a decrement in their saline intake while female hamsters showed no significant change in these pre- and post-withdrawal measures. In Experiment 2, a between-groups design was used to test for differences between the saline intake of hamsters and gerbils exposed to the experimental (saline withdrawal) and control (no withdrawal) conditions. When tested with 0.45% or 2.0% saline solution, there was no significant difference between experimental and control hamsters. The results with male gerbils indicated a significant withdrawal effect when the animals were tested with 3.0% saline but not with 4.0% NaCl solution. The implications of these results for a behavioral taxonomy of “compensators” and “noncompensators” are discussed.     

Effects of nutrients on germination of Verticillium lecanii (=Lecanicillium sp.) conidia and infection of greenhouse whitefly, (Trialeurodes vaporariorum)

Laboratory experiments were conducted to assess effects of nutrients on germination of Verticillium lecanii (=Lecanicillium sp.) conidia and infection of the greenhouse whitefly, Trialeurodes vaporariorum. Suspensions of V. lecanii conidia were prepared in four nutrient solutions: 2% glucose, 2% sucrose, 2% maltose, and 2% peptone. Suspensions in de-mineralized water served as the control. At 23°C the germination rate was highest in the 2% glucose solution, followed by sucrose, maltose, demineralized water, and peptone, respectively. Germ tube growth was greatest at 23°C in the 2% glucose solution after 10 h incubation. Results of the bioassays indicated that the nutrients influenced whitefly infection. Infection levels were highest for conidial suspensions (1×10⁶ conidia/mL) prepared in 2% glucose, and were significantly greater than for peptone, demineralized water and maltose. Infection levels at 1×10⁸ conidia/mL were not significantly different from each other for all materials tested. The potential use of nutrients in a spray formulation as a means of enhancing field efficacy are discussed.