Detection of Enterococcus cecorum to identify persistently contaminated locations using faecal and environmental samples in broiler houses of clinically healthy flocks.

RESEARCH HIGHLIGHTS: Methodology is suitable to detect EC during production and after C&D.Locations were detected that may serve as a reservoir for EC.Cycles with fewer positive samples were observed.Cleaning and disinfection had a major impact on the detection of EC.

Research Note: Preliminary results, first detection of Enterococcus cecorum from environmental samples by streaking on X-Gluc containing selective media.

The isolation of cultivable E. cecorum from the environment of poultry houses remains a challenge. Environmental samples (dust wipes, equipment swabs, pooled feces) and samples from culled bird vertebras were collected from an infected broiler flock on d 37 posthatching. To isolate the bacterium from the cultivable microbiota, suspensions from the environmental samples were streaked onto a blood agar base medium supplemented with 5-bromo-4-chloro-3-indolyl-beta-D-glucuronic acid cyclohexylammonium salt (X-Gluc), colistin sulfate, and nalidixin. The chromogenic reaction facilitated the isolation of E. cecorum from contaminated surfaces and pooled feces. Isolates from both the environment and vertebras were confirmed using MALDI-TOF and PCR analysis. Colony appearance and antimicrobial susceptibility tests revealed no phenotypic differences among the isolates. It remained unclear whether the isolates originated from the same clone. However, the principle of isolating the pathogen by streaking on a chromogenic agar may motivate researchers to investigate the transmission routes of infectious isolates, potentially leading to the optimization of biosecurity measures.

Effects of maternal and offspring treatment with two dietary sources of vitamin D on the mineral homeostasis, bone metabolism and locomotion of offspring fed protein- and phosphorus-reduced diets.

The present study aims to compare the effects of maternal and offspring treatment with 25-hydroxycholecalciferol (25-OHD3) and vitamin D3 on vitamin D status, mineral homoeostasis, bone metabolism and locomotion in the offspring. Either vitamin D3 (50 µg/kg diet) or 25-OHD3 (50 µg/kg diet) was supplemented to the gestation and lactation diets of 49 multiparous sows and/or to the diets of their growing offspring. Treatment of the sows did not affect plasma concentrations of 25-OHD3 of the offspring. Pigs fed 25-OHD3 had higher plasma concentrations of 25-OHD3 than pigs that received vitamin D3 during rearing and fattening. However, neither plasma concentrations of calcium, phosphate and bone markers during the observation period nor bone ash and bone mineral density at slaughter were clearly affected by the treatment. Maternal and offspring treatment with 25-OHD3 instead of vitamin D3 resulted in a slight reduction in the prevalence of leg swelling. In addition, more pigs walked with even steps and normal stride length. Further studies are needed to test whether the slight effects observed in the present experiment are reproducible and of relevance for animal health and welfare. In that case, the underlying mechanisms should be revealed in order to take advantage of potentially beneficial influences especially under certain feeding regimes.

Heat Stress Trends in Regions of Intensive Turkey Production in Germany-A Challenge in Times of Climate Change.

This study analyzed trends of enthalpy and the temperature-humidity index (THI) over a period of 50 years in outer air, which lead to severe heat stress in turkeys. Weather station data from 15 German districts with high densities of turkey production were used to investigate the heat input into the barns. Therefore, the parameters of enthalpy and THI with specified thresholds were used for heat stress assessment. Trends in extreme weather situations where these thresholds were exceeded were analyzed and tested for significance using the Mann-Kendall test. In all districts, the heat load increased between 1973 and 2022 for both parameters. Statistically significant heat stress trends were found in 9 of the 15 districts for enthalpy and 14 out of 15 districts for THI. Thus, the established THI thresholds seem to be more sensitive for the detection of heat stress than the chosen enthalpy values. As heat stress is an important issue and a rising concern in times of climate change, farmers and constructors of farm animal facilities should take this into account in future sustainable work.

Dietary supplementation of 25-hydroxycholecalciferol as an alternative to cholecalciferol in swine diets: A review.

25-hydroxycholecalciferol (25-OHD3 ) formed via hepatic hydroxylation from vitamin D, cholecalciferol, represents the precursor of the biologically active vitamin D hormone, 1,25-dihydroxyvitamin D. Due to a higher absorption rate and the omission of one hydroxylation, dietary supplementation of 25-OHD3 instead of vitamin D3 is considered to be more efficient as plasma concentrations of 25-OHD3 are increased more pronounced. The present review summarises studies investigating potential beneficial effects on mineral homeostasis, bone metabolism, health status and performance in sows, piglets and fattening pigs. Results are inconsistent. While most studies could not demonstrate any or only a slight impact of partial or total replacement of vitamin D3 by 25-OHD3 , some experiments indicated that 25-OHD3 might alter physiological processes when animals are challenged, for example, by a restricted mineral supply.

Effectiveness of air-purifying devices and measures to reduce the exposure to bioaerosols in school classrooms.

The SARS-CoV-2 pandemic, which suddenly appeared at the beginning of 2020, revealed our knowledge deficits in terms of ventilation and air pollution control. It took many weeks to realize that aerosols are the main route of transmission. The initial attempt to hold back these aerosols through textile masks seemed almost helpless, although there is sufficient knowledge about the retention capacity of fabric filters for aerosols. In the absence of a sufficient number of permanently installed heating, ventilation, and air conditioning systems, three main approaches are pursued: (a) increasing the air exchange rate by supplying fresh air, (b) using mobile air purifiers, and (c) disinfection by introducing active substances into the room air. This article discusses the feasibility of these different approaches critically. It also provides experimental results of air exchange measurements in a school classroom that is equipped with a built-in fan for supplying fresh air. With such a fan and a window tilted at the appropriate distance, an air exchange rate of 5/h can be set at a low power level and without any significant noise pollution. Heat balance calculations show that no additional heat exchanger is necessary in a normal classroom with outside temperatures above 10°C. Furthermore, a commercial mobile air purifier is studied in a chamber and a test room setup in order to examine and evaluate the efficiency of such devices against viable viruses under controlled and realistic conditions. For this purpose, bacteriophages of the type MS2 are used. Both window ventilation and air purifiers were found to be suitable to reduce the concentration of phages in the room.

Comparative Study of the Effects of Two Dietary Sources of Vitamin D on the Bone Metabolism, Welfare and Birth Progress of Sows Fed Protein- and Phosphorus-Reduced Diets.

To investigate the influence of two dietary sources of vitamin D on the vitamin D status, bone metabolism, welfare and birth progress of gestating and lactating sows, forty-nine multiparous sows were randomly assigned to one of two diets: "CON" (n = 25; 50 µg vitamin D3/kg feed) and "HYD" (n = 24; 50 µg 25-hydroxycholecalciferol/kg feed). The basal diets were protein- and phosphorus-reduced. The trial started on day 3 ante insemination of the sows and ended with weaning of the piglets on day 28 postpartum. Dietary supplementation of 25-hydroxycholecalciferol resulted in improved maternal vitamin D status (p < 0.001), fewer gait changes (p < 0.01) and longer standing time after feeding (day 5 ante partum; p < 0.05) compared to vitamin D3. However, the bone markers CrossLaps and osteocalcin were not affected. Overall, the present results suggest that sows fed 25-hydroxycholecalciferol instead of vitamin D3 showed improved locomotion and stance strength. However, this outcome is probably not related to altered bone metabolism. The underlying mechanisms must be investigated in further studies.

Innovative Perspectives on Biofilm Interactions in Poultry Drinking Water Systems and Veterinary Antibiotics Used Worldwide.

Prudent use of antibiotics in livestock is widely considered to be important to prevent antibiotic resistance. This study aimed to evaluate the interactions between biofilms and veterinary antibiotics in therapeutic concentrations administrated via drinking water through a standardized experimental setup. In this context, two biofilms formed by pseudomonads (Pseudomonas (P.) aeruginosa or P. fluorescens) and a susceptible Escherichia (E.) coli strain were developed in a nutrient-poor medium on the inner surface of polyvinyl chloride pipe pieces. Subsequently, developing biofilms were exposed to sulfadiazine/trimethoprim (SDZ/TMP) or tylosin A (TYL A) in dosages recommended for application in drinking water for 5 or 7 days, respectively. Various interactions were detected between biofilms and antibiotics. Microbiological examinations revealed that only TYL A reduced the number of bacteria on the surface of the pipes. Additionally, susceptible E. coli survived both antibiotic treatments without observable changes in the minimum inhibitory concentration to 13 relevant antibiotics. Furthermore, as demonstrated by HPLC-UV, the dynamics of SDZ/TMP and TYL A in liquid media differed between the biofilms of both pseudomonads over the exposure period. We conclude that this approach represents an innovative step toward the effective evaluation of safe veterinary antibiotic use.

[Investigations on suckling piglets castrated under automated isoflurane anesthesia]. / Untersuchungen zur automatisierten Isoflurannarkose bei der Saugferkelkastration.

OBJECTIVE: Investigation of defensive reactions, piglet losses, post-bleeding and recovery time of suckling piglets castrated under automated isoflurane anesthesia as well as measurements of isoflurane concentrations in ambient air and estimation of the cleaning and disinfection success of anesthesia masks. MATERIAL AND METHODS: A total of 955 suckling piglets (age: 4.0 ± 1.2 days; weight: 2.0 ± 0.5 kg) were castrated under automated isoflurane anesthesia (PorcAnest 3000®) after the administration of a non-steroidal anti-inflammatory drug. Reactions during the procedure were assessed before castration using the interdigital claw reflex and during castration by defensive movements and vocal response. The piglets' recovery time was evaluated in the stable corridor (pass 1) and the farrowing pen (passes 4-5). In 73 animals, the spermatic cord was cut with a scalpel and the post-operative bleeding visually evaluated. In addition, exposure measurements of isoflurane were performed and anesthetic masks were examined for total bacterial contamination and indicator bacteria before and after the anesthetic procedure and following their disinfection. RESULTS: Following insufflation of isoflurane for 90 seconds 94.3 % of the piglets and after prior testing of the interdigital claw reflex and possible extension of the anesthetic supply 95.3 % of the piglets showed no or minimal defensive movements during castration. An anesthetic incident occurred in 0.9 % of the piglets, but no animal died. The recovery time lasted 7.3 ± 4.7 minutes (pass 1) and 6.2 ± 3.3 minutes (passes 4-5). Cutting the spermatic cord with a scalpel led to a higher post-bleeding score (p < 0.001) compared to use of the emasculator. Isoflurane concentrations in ambient air ranged between 4.5 und 28.1 mg/m3. Masks disinfection reduced the total germ count by 99.8 %. Contaminations with Escherichia coli and MRSA were no longer detectable in 4 of 6 cases after disinfection. CONCLUSION: Isoflurane anesthesia led in over 94 % of the piglets to no or minimal defensive reactions during castration. Anesthetic incidents occurred rarely and no piglet losses were recorded. Therefore, automated isoflurane anesthesia is associated with a low risk for suckling piglets. Measurements of isoflurane concentrations on persons involved were below the internationally lowest limit value. Disinfection of the anesthesia masks may prevent germ transmission between animal groups via this potential vector.

Effects of a slatted floor on bacteria and physical parameters in litter in broiler houses.

In this study, a new housing system for broiler was tested. This system consisted of a slatted floor area and a littered area with the aim of improving litter quality. Two experimental broiler houses were provided. In house 1, a slatted floor was installed below the drinker and feedlines. Littered areas flanked the slatted floor. Broiler house 2 reflected conditions in commercial systems, consisting of a full littered area. Litter samples were taken at day 11 and at day 32 of the fattening period. Manure samples were taken at day 32. The total bacteria count (TBC), coliforms, Escherichia coli (E. coli) and ESBL-producing bacteria were determined. Furthermore, physical parameters (dry matter, water activity, pH) of litter and manure were measured. For statistical analyzes, a generalized linear mixed model (GLIMMIX procedure) was calculated. The floor did not show any significant effect on the bacteria content of the litter. Regarding TBC in litter, the floor showed a tendency for an effect (F = 5.42, p<0.1) with lower contents in house 1. Regarding the manure under the slatted floor, a tendency for a difference between house 1 and house 2 was found for the content of E. coli (F = 5.55, p<0.1) with higher contents in house 1. The floor did not show any significant effect on the physical parameters of litter and manure. The results of this experimental study showed no positive effects on the selected litter parameters, but further studies, especially on-farm experiments are necessary to confirm these results.

Occurrence of extended-spectrum beta-lactamase-producing Enterobacteriaceae, microbial loads, and endotoxin levels in dust from laying hen houses in Egypt.

BACKGROUND: Poultry houses are often highly contaminated with dust, which might contain considerable amounts of microorganisms and endotoxins. The concentrations of microorganisms and endotoxins in dust from laying hen houses in Egypt are unknown. However, to estimate the risks for birds, the environment, and people working in laying hen houses, it is important to gather information about the composition of these dusts. Here we report the microbial loads, the occurrence of antimicrobial-resistant bacteria, and endotoxin concentrations in dust samples from 28 laying hen farms in Dakahliya Governorate, Egypt, and discuss the results relevant to the literature. RESULTS: Pooled settled dust samples (n = 28) were analyzed for total viable counts of bacteria and fungi (CFU/g), the occurrence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, Salmonella spp., and methicillin-resistant Staphylococcus aureus (MRSA), and endotoxin concentrations (ng/g). The means and standard deviations of total viable counts were 7.10 × 108 ± 2.55 × 109 CFU/g for bacteria and 5.37 × 106 ± 7.26 × 106 CFU/g for fungi. Endotoxin levels varied from 2.9 × 104 to 6.27 × 105 ng/g. None of the tested samples contained Salmonella spp. or MRSA. In contrast, by direct plating, Enterobacteriaceae were found frequently (57%; n = 16), and suspected ESBL-producing Enterobacteriaceae occurred in 21% (n = 6) of the sampled barns. Using an enrichment method, the detection of Enterobacteriaceae and suspected ESBL-producing Enterobacteriaceae increased to 20 and 16 positive barns, respectively. Taking results from both methods into account, Enterobacteriaceae and suspected ESBL-producing Enterobacteriaceae were detected in 23 barns Overall, 100 ESBL suspected isolates (Escherichia coli, n = 64; Enterobacter cloacae, n = 20; and Klebsiella pneumoniae n = 16) were identified to species level by MALDI-TOF MS. Isolates from 20 barns (71% positive barns) were confirmed as ESBL producing Enterobacteriaceae by the broth microdilution test. CONCLUSIONS: Dust in Egyptian laying hen houses contains high concentrations of microorganisms and endotoxins, which might impair the health of birds and farmers when inhaled. Furthermore, laying hens in Egypt seem to be a reservoir for ESBL-producing Enterobacteriaceae. Thus, farmers are at risk of exposure to ESBL-producing bacteria, and colonized hens might transmit these bacteria into the food chain.

Low-frequency electromagnetic fields as an alternative to sanitize water of drinking systems in poultry production?

Low-frequency electromagnetic fields (LF-EMF) may present an alternative to conventional sanitation methods of water supply lines in animal production. The objective of this study was to evaluate the effect of the application of LF-EMF on bacterial concentrations and biofilms at scale-models of different drinking systems (circulating and non-circulating) conventionally used in poultry holdings. Treated systems were equipped with commercial devices producing pulsed electromagnetic signals of low frequency up to 10,000 Hz; max. 21 mT. Exposure of water to LF-EMF resulted in changes of the culturable bacterial counts, although with high standard deviations. Differing between systems types, LF-EMF treatment seemed to be responsible either for a limitation or for an increase of colony forming unit counts, with partly statistically significant differences, especially in early stages of treatment. In contrast, neither biofilm formation nor counts of cells suspended in water differed between treated and control lines over 28 days of experiment, as determined by fluorescence microscopy. Although this study indicates that LF-EMF may influence culturability of water microorganisms, no clear inhibitory effects on bacterial biofilm formation or on planktonic microbes by LF-EMF treatment were confirmed in the experiments.

Haptoglobin and C-Reactive Protein-Non-specific Markers for Nursery Conditions in Swine.

A quality concept for production in the pork market includes granting a good health status of pigs from birth to slaughter. This concept is a precondition for animal welfare as well as reducing antibiotic usage in farm animals. The demand for fighting bacterial antimicrobial resistance in humans, animals, and in the environment is one driving force for the development of innovative technical solutions to improve husbandry. Maintenance of a good health status in pigs depends on early detection of a disturbance in homeostasis in critical phases of life. This can be measured by non-specific biomarkers as acute phase proteins. In this project, husbandry conditions and health status in nursery pigs were monitored in an autumn and winter nursery period from weaning to the end of nursery in two compartments with 180 pigs each. It was investigated whether a slight modification in indoor climate achieved by a new ammonia sensory technology coupled with the electronic control unit of the forced ventilation system ensuring ammonia levels lower than 5 ± 3 ppm in one compartment led to a better health status in piglets in comparison to the control compartment. In the examined nursery periods in different seasons, ammonia concentrations in the experimental compartment were significantly lower than in the control compartment, thus proving the functionality and efficacy of the technical system. Production parameters as feed conversion rate and average daily weight gain were slightly improved in the experimental compartment without implementing other measures. Multifactorial analysis of variance resulted in a significant influence of season, daily quarter, and compartment on ammonia concentration. The challenge to preserve a high health status of piglets also during suboptimal outside climate in the transitional season was reflected by an increase in the acute-phase proteins haptoglobin (Hp) and C-reactive protein (CRP) in autumn compared to winter. The seasonal influence on concentrations of CRP and Hp superimposed potential influences of the climate modification. New technological concepts to reduce noxious gases and dust in the animal environment as well as emissions, which in parallel guarantee optimal temperatures also during extreme weather conditions, can be evaluated by clinical data in combination with biomarkers.

Analysis of fluoroquinolones in dusts from intensive livestock farming and the co-occurrence of fluoroquinolone-resistant Escherichia coli.

Fluoroquinolones are important therapeutics in human and veterinary medicine. This study aimed to retrospectively analyse sedimentation dusts from intensive-livestock-farming barns for fluoroquinolones and investigate the association between resistant Escherichia coli and the detected drugs. Sedimentation-dust samples (n = 125) collected (1980-2009) at 14 barns of unknown-treatment status were analysed by HPLC and tandem-mass spectroscopy to detect enrofloxacin, ciprofloxacin, marbofloxacin, and difloxacin. Recent microbiological data were included to investigate the relationship between fluoroquinolone presence and fluoroquinolone-resistant E. coli. Fifty-nine dust samples (47%) from seven barns contained fluoroquinolone residues. Up to three different fluoroquinolones were detected in pig and broiler barns. Fluoroquinolone concentrations ranged from 10-pg/mg to 46-ng/mg dust. Fluoroquinolone-resistant E. coli were isolated from four barns. Of all the dust samples, 22% contained non-susceptible isolates. Non-susceptible isolate presence in the dust was significantly associated (p = 0.0283) with detecting the drugs, while drug detection increased the odds (4-fold) of finding non-susceptible E. coli (odds ratio = 3.9877, 95% CI: 1.2854-12.3712). This retrospective study shows that fluoroquinolone usage leads to dust contamination. We conclude that farmers and animals inhale/swallow fluoroquinolones and fluoroquinolone-resistant bacteria due to drug application. Furthermore, uncontrolled drug emissions via air exhausted from the barns can be assumed.

Use of Three Air Samplers for the Detection of PRRSV-1 under Experimental and Field Conditions.

Airborne transmission of porcine reproductive and respiratory syndrome virus (PRRSV) has been known for a long time. Most experiments were performed using PRRSV-2 strains and fairly little information is available on the airborne spread of PRRSV-1. The aim of this study was to assess three different air samplers for their ability to detect PRRSV-1 under experimental and field conditions. All three devices were able to detect PRRSV-1 by quantitative reverse trascription polymerase chain reaction (qRT-PCR) under experimental conditions. However, the detection of PRRSV-1 in a PRRSV-positive farm with active virus circulation was not successful.

Examination of the hygienic status of selected organic enrichment materials used in pig farming with special emphasis on pathogenic bacteria.

BACKGROUND: Enrichment materials for pigs, particularly organic materials, are becoming increasingly important in order to reduce abnormal behaviour such as tail biting. However, potential health risks posed by these materials (such as the introduction of pathogens into the herd) have not been sufficiently studied to date. Therefore, 21 different organic materials used as enrichment materials in pig farming were tested for total viable count of mesophilic bacteria, moulds, coliforms, Escherichia coli, Klebsiella spp., Yersinia spp., Salmonella spp., methicillin-resistant Staphylococcus aureus, and Mycobacterium spp. Additionally, dry matter content and water activity were determined. RESULTS: The materials differed considerably in their hygienic status. In three materials, no microorganisms were detected. However, the bacterial count in the other materials ranged up to 7.89 log10 cfu/g dry matter (maize silage). The highest coliform and mould counts were found in hay (6.45 and 6.94 log10 cfu/g dry matter, respectively). Important bacteria presenting a risk to human or animal health such as Escherichia coli, Klebsiella spp., Yersinia spp., Salmonella spp., and methicillin-resistant Staphylococcus aureus were not detected in any of the materials. Hemp straw contained Mycobacterium smegmatis, and peat was contaminated with Mycobacterium avium and Mycobacterium vulneris. CONCLUSIONS: Most of the tested organic materials are probably not likely to pose a hygienic risk to pigs and are suitable as enrichment material. Nonetheless the detected mycobacteria rule out peat as being a safe and hygienic enrichment material.

Resistance of Enterococcus spp. in Dust From Farm Animal Houses: A Retrospective Study.

In a retrospective study, the antimicrobial susceptibility of Enterococcus spp. isolated from stored sedimentation dust samples from cattle, pig and poultry barns to 16 antibiotics was determined using a microdilution test. The resistance phenotypes of 70 isolates from different timespans (8 from the 1980s, 15 from the 1990s, 43 from the 2000s and 4 from 2015) were determined. Resistant enterococci were detected in samples from all time periods. Resistances to three or more antibiotics occurred in 69 percent of all isolates. The oldest multidrug resistant isolate was an Enterococcus faecium obtained from a 35-year-old pig barn dust sample. No correlations (ρ = 0.16, p = 0.187) were found between the age of isolates and the number of resistances. Instead, the number of resistances was associated with the origin of the isolates. An exact logistic conditional regression analysis showed significant differences in resistance to ciprofloxacin, erythromycin, penicillin and tylosin between isolates from different animal groups. Interestingly, we isolated ciprofloxacin-resistant E. faecium from pig barn dust before fluoroquinolones were introduced into the market for use in animal husbandry. In conclusion, dust from farm animal houses is a reservoir and carrier of multidrug-resistant Enterococcus spp. People working in barns are unavoidably exposed to these bacteria. Furthermore, it can be hypothesized that emissions from barns of intensive livestock farming contaminate the environment with multidrug resistant enterococci.

Fogging low concentrated organic acid in a fattening pig unit - Effect on animal health and microclimate.

INTRODUCTION AND OBJECTIVE: In intensive pig production aerial contaminates are potential hazards for the health of animals and humans. In this study, the effect of fogging a low concentrated tartaric acid solution on pigs' health, environmental and hygiene parameters were evaluated in an inhabited fattening unit. MATERIALS AND METHOD: Pigs were housed in separate units (control group n=109 and experimental group n=110). During the whole fattening period, twice a week at 48 hour intervals, a 0.1% tartaric acid solution was aerosolized by a cold-fogging system for 20 minutes in the experimental unit. Environmental parameters were spot-checked on days of fogging. Sedimentation dust and surfaces were analysed for bacterial and fungal load. Dust particle size distribution was assessed. Pigs were clinically examined weekly. Standard meat examination at an abattoir was extended by individual quantification of lung alterations. RESULTS: The fogging procedure had no influence on ammonia concentrations. A significant reduction of mould, but not of bacteria, was found in sedimentation dust, and bacterial and mould scores of surface samples were improved. A significant reduction of particle size classes 1.6-2.0 µm, 4.0-5.0 µm, 7.5-10 µm, as well as 10-15 µm was observed. The high sound level of the fogging machine (82-102 dB) led to higher activity and pen-mate directed behaviour. More skin alterations, conjunctivitis and sneezing were recorded in the experimental group. Gross pathological lung alterations did not differ between both groups. CONCLUSIONS: Although fogging of tartaric acid is limited to a concentration of 0.1% due to its irritating effect on the respiratory mucosa, reduction of microbial load can be achieved, but it would be enhanced by using more powerful fogging systems.

Antimicrobial-Resistant Escherichia coli Survived in Dust Samples for More than 20 Years.

In a retrospective study, 119 sedimentation dust samples stored between five and 35 years from various barns of intensive livestock farming were evaluated for the occurrence of cultivatable Escherichia coli. Growth of E. coli occurred in 54 samples. Successful cultivation was achieved in samples from as early as 1994. The frequency of detection increased from earlier to later time periods, but the concentrations, which ranged between 3.4 × 10(2) and 1.1 × 10(5) colony-forming units per gram, did not correlate with sample age (Spearman rank correlation; p > 0.05). We hypothesize that E. coli cells survived in dust samples without cell division because of the storage conditions. Dry material (dust) with low water activities (arithmetic mean < 0.6) and storage at 4°C in the dark likely facilitated long-term survival. E. coli were isolated on MacConkey agar with and without ciprofloxacin supplementation. For 110 isolates (79 from non-supplemented media and 31 from supplemented media), we determined the E. coli phylotype and antimicrobial resistance. Six phylogenetic groups were identified. Phylogroups A and B1 predominated. Compared to group A, phylogroup B1 was significantly associated with growth on ciprofloxacin-supplemented media (chi-square test, p = 0.003). Furthermore, the antibiotic resistance profiles determined by a microdilution method revealed that isolates were phenotypically resistant to at least one antimicrobial substance and that more than 50% were resistant to a minimum of five out of 10 antibiotics tested. A linear mixed model was used to identify factors associated with the number of phenotypic resistances of individual isolates. Younger isolates and isolates from fattening poultry barns tended to be resistant to significantly more antibiotics than older isolates and those from laying-hen houses (p = 0.01 and p = 0.02, respectively). Sample origin and storage conditions may have influenced the number of antimicrobial resistances. Overall, we found that under particular conditions, dust from farm animal houses can be reservoirs for antimicrobial-resistant E. coli for at least 20 years. The survival strategies that allow E. coli to survive such long periods in environmental samples are not fully understood and could be an interesting research topic for future studies.

The effect of miscellaneous oral dosage forms on the environmental pollution of sulfonamides in pig holdings.

BACKGROUND: Due to antibiotic treatment of humans and animals, the prevalence of bacterial resistances increases worldwide. Especially in livestock farming, large quantities of faeces contaminated with antibiotics pose a risk of the carryover of the active ingredient to the environment. Accordingly, the aim of the present study was the evaluation of the benefit of different oral dosage forms (powder, pellets, granula) in pigs concerning the environmental pollution of sulfadiazine. Two subtherapeutic dosages were evaluated in powder mixtures to gain information about their potential to pollute the pig barn. Furthermore, a new group of pigs was kept in the stable after powder feeding of another pig group to determine the possible absorption of environmentally distributed antibiotics. Pigs were orally treated with three dosage forms. Simultaneously, sedimentation and airborne dust were collected and plasma and urine levels were determined. RESULTS: All formulations result in comparable plasma and urine levels, but massive differences in environmental pollution (powder > pellets, granula). Pigs housing in a contaminated barn exhibit traces of sulfadiazine in plasma and urine. CONCLUSION: Using pharmaceutical formulations like pellets or granula, the environmental pollution of sulfonamides can significantly be diminished due to massive dust reduction during feeding.