The horizontal transfer of Salmonella between the lesser mealworm (Alphitobius diaperinus) and poultry manure

The bacterial and archaeal communities of flies, manure, lagoons, and troughs at a working dairy

Background

Fundamental investigations into the location, load, and persistence of microbes, whether beneficial or detrimental, are scarce. Many questions about the retention and survival of microbes on various surfaces, as well as the load necessary for spread, exist. To answer these questions, we must know more about where to find various microbes and in what concentrations, the composition of the microbial communities, and the extent of dissemination between various elements. This study investigated the diversity, composition, and relative abundance of the communities associated with manure, lagoons, troughs, house flies, and stable flies present at a dairy, implementing two different free-stall management systems: flow-through and cross-vent. Shotgun metagenomics at the community level was used to compare the microbiomes within the dairy, allowing confident interpretation at the species level.

Results

The results showed that there were significant difference in microbial composition between not only each of the dairy elements but also management styles. The primary exceptions were the microbiomes of the house fly and the stable fly. Their compositions heavily overlapped with one another, but interestingly, not with the other components sampled. Additionally, both species of flies carried more pathogens than the other elements of the dairy, indicating that they may not share these organisms with the other components, or that the environments offered by the other components are unsatisfactory for the survival of some pathogens..

Conclusion

The lack of overlapping pathogen profiles suggests a lack of transfer from flies to other dairy elements. Dairy health data, showing a low incidence of disease, suggests minimal sharing of bacteria by the flies at a level required for infection, given the health program of this dairy. While flies did carry a multitude of pathogenic bacteria, the mere presence of the bacteria associated with the flies did not necessarily translate into high risk leading to morbidity and mortality at this dairy. Thus, using flies as the sole sentinel of dairy health may not be appropriate for all bacterial pathogens or dairies.

Synergistic interactions between three insecticides and Beauveria bassiana (Bals.-Criv.) Vuill. (Ascomycota: Hypocreales) in lesser mealworm, Alphitobius diaperinus Panzer (Coleoptera: Tenebrionidae), larvae

Topical applications of insecticides β-cyfluthrin, imidacloprid, and spinosad in combination with Beauveria bassiana (topical and contact filter paper application) induced synergistic interactions in lesser mealworm larvae, increasing mortality and in some cases numbers of larval cadavers exhibiting conidiogenesis. Reduced concentrations (LC10, LC20, LC30) of the insecticides induced sublethal effects in lesser mealworm larvae, inhibiting development (mass, head-capsule width, moulting) after eight days' exposure and movement behaviour (area explored and distance travelled) after 3 h' exposure. The most potent synergist was ß-cyfluthrin, it strongly inhibited larval development and movement while significantly increasing mortality and conidiogenesis in B. bassiana-infected larvae. Imidacloprid also strongly inhibited larval development and movement, but only produced weak short-lived synergistic increases in mortality, with no increase in conidiogenesis. Spinosad induced no effect on development and limited effect on movement, but still induced moderate short-lived synergistic increases in mortality and conidiogenesis. Intoxicated larvae exposed to B. bassiana on filter paper for 3 h showed no synergistic interactions, except when intoxicated by spinosad.

Large-scale production of house fly, Musca domestica (Diptera: Muscidae), larvae fed 3 manure types

House flies, Musca domestica, L., (Diptera: Muscidae) are well-known pests at animal facilities; however, they can be used for manure biodegradation. Utilizing house flies to process animal manure offers a means to recycle nutrients and reduce contaminants (e.g., pathogens and heavy metals), while also producing multiple revenue streams (e.g., protein for feed, fat for biodiesel, frass as a soil amendment). This study determined house fly larval performance on a larger scale (kilogram of wastes; thousands of larvae; single feeding) as a follow-up to a previous experiment performed at a bench-top scale (g of wastes; hundreds of larvae; incremental feeding). Four thousand larvae were fed 1 kg of swine, dairy, or poultry manure, or a control (Gainesville diet: 50% wheat bran, 30% alfalfa meal, and 20% corn meal). Peak larval weight occurred 4 days after inoculation and no significant difference in development time to first pupariation occurred across diets. However, percent survivorship to pupariation varied, with the highest occurring in Gainesville (74%), swine (73%), and poultry (67%) manure, whereas 50% survived when fed dairy manure. The highest pupal weight was found for those fed Gainesville (27 mg), and similar weights were found for those fed swine (21 mg), dairy (24 mg), and poultry (25 mg) manure. Although using house flies to manage manure has received little consideration in Western countries, other regions have this practice in place. Results may provide insight on differences between small- and large-scale studies, which is valuable for industrialization of this species for waste management and creating a more circular economy.

Management Practices Affecting Lesser Mealworm Larvae (Alphitobius diaperinus) Associated Microbial Community in a Broiler House and After Relocating With the Litter Into Pastureland

Lesser mealworms are often found infesting production houses used to raise broiler chickens. Previous studies have investigated pathogenic microorganisms associated with the larvae, but a more thorough study relating total microbiome changes due to management procedures and flock rotations was needed. Additionally, there is a question of what microbiota are transferred into the environment when the litter, in which larvae reside, is piled in pastureland for use as fertilizer and where interactions with the soil and other fauna can occur. This study chronicled, by the 16S rRNA sequencing, the bacterial community profile of larvae in a broiler grow-out house synchronizing to when birds were added to and removed from the house over 2.5 years. The profile was found to be relatively constant despite 11 flock rotations and management disruptions, specifically litter cleanout procedures and the addition of new birds or bedding. In contrast, once removed from the controlled broiler house environment and placed into open pastureland, the substantial microbial diversity brought with the larvae showed greater fluctuation in structure with environmental conditions, one of which was rainfall. Surprisingly, these larvae survived at least 19 weeks, so the potential for moving larval-associated microbes into the environment needs further assessment to minimize the risk of relocating foodborne pathogens and also to assess those bacteria-generating metabolites that have benefits to plant growth when using the litter as a fertilizer. The characterization of their microbiome is the first step to investigating the influences of their microbes on the manmade and environmental ecosystems.

Alphitobius diaperinus Panzer (Insecta, Coleoptera) in a single house of a broiler production facility as a potential source of pathogenic bacteria for broilers and humans

Pest infestation in any stage can lead to a quality reduction in the finished products. This study aimed to detect Escherichia coli, Salmonella spp., Campylobacter spp., and Staphylococcus aureus in Alphitobius diaperinus adults, and in samples from broiler swabs, administered water and feed collected in a single house from a broiler production facility in central Italy. Three samplings were carried out, each collecting ninety adult beetles for microbial detection in the external, fecal and internal content; ten cloacal swab samples; and one sample of both administered feed and water. Microbiological cultures and biochemical identification were performed on suspected cultures and confirmed by species-specific PCRs. A. diaperinus was abundantly found near the windows, under the manger and in the corners of the facility. Salmonella enterica serovar Cholerasuis was found at the external surface of the beetles, while Staphylococcus xylosus and E. coli in the fecal content. The latter microrganism together with Staphylococcus lentus, S. xylosus and other staphylococcal species were detected in the internal microbiota. E. coli and Campylobacter spp. were observed in cloacal swabs, and S. xylosus in one feed sample. The study findings support evidence for Salmonella spp. and E. coli, and remark that adherence with sanitation rules and biosecurity procedures are required.

Adult Alphitobius diaperinus Microbial Community during Broiler Production and in Spent Litter after Stockpiling

The facilities used to raise broiler chickens are often infested with litter beetles (lesser mealworm, Alphitobius diaperinus). These beetles have been studied for their carriage of pathogenic microbes; however, a more comprehensive microbiome study on these arthropods is lacking. This study investigated their microbial community in a longitudinal study throughout 2.5 years of poultry production and after the spent litter, containing the mealworms, was piled in pastureland for use as fertilizer. The mean most abundant phyla harbored by the beetles in house were the Proteobacteria (39.8%), then Firmicutes (30.8%), Actinobacteria (21.1%), Tenericutes (5.1%), and Bacteroidetes (1.6%). The community showed a modest decrease in Firmicutes and increase in Proteobacteria over successive flock rotations. The beetles were relocated within the spent litter to pastureland, where they were found at least 19 weeks later. Over time in the pastureland, their microbial profile underwent a large decrease in the percent of Firmicutes (20.5%). The lesser mealworm showed an ability to survive long-term in the open environment within the spent litter, where their microbiome should be further assessed to both reduce the risk of transferring harmful bacteria, as well as to enhance their contribution when the litter is used as a fertilizer.

Insecticidal Effect of Weeds Extract in the Poultry Pest Alphitobius diaperinus

&lt;b&gt;Background and Objective:&lt;/b&gt; &lt;i&gt;Alphitobius diaperinus&lt;/i&gt; (Coleoptera: Tenebrionidae) is the major pest in chicken farms. The control of pests using synthetic insecticides is not recommended. Besides its expensive, synthetic insecticides are proved harmful to poultry health, farmworkers and polluting the environment. To explore the sources of bioinsecticides that are cheap and eco-friendly, this study was conducted to evaluate the insecticidal effect of weeds extracts (&lt;i&gt;Chromolaena odorata&lt;/i&gt;, &lt;i&gt;Ageratum conyzoides&lt;/i&gt; and &lt;i&gt;Tithonia diversifolia&lt;/i&gt;) against post-embryonic survival of &lt;i&gt;A. diaperinus&lt;/i&gt;. &lt;b&gt;Materials and Methods:&lt;/b&gt; The experimental study using a completely randomized design of 2 factors, i.e., 3 types of weeds extract and 6 levels of concentration. The insecticidal effect was observed based on the post-embryonic survival. The post-embryonic survival of larvae was evaluated for 4 weeks by measuring the number of Larvae Released (LR) from the eggs, as well as the number of Adults Emergence (AE). Data were analyzed using Variance Analysis (ANOVA) and continued with the least significant different tests (α&lt;u&gt;<&lt;/u&gt;0.5). &lt;b&gt;Results:&lt;/b&gt; The statistical analysis showed that the differences in extract concentration contributed significant influence (α&lt;u&gt;<&lt;/u&gt;0.05) on the total number of larvae released and adult emergence. The lowest LR and AE occurred at the 40% concentration level, i.e., on the extract of &lt;i&gt;T. diversifolia&lt;/i&gt;, while the highest LR and AE were found in the treatment of &lt;i&gt;C. odorata&lt;/i&gt; extract. &lt;b&gt;Conclusion:&lt;/b&gt; In this study, all types of extracts have an insecticidal effect on the post-embryonic survival of &lt;i&gt;A. diaperinus&lt;/i&gt; but the strongest effect was found in the extract of &lt;i&gt;T. diversifolia&lt;/i&gt; in 40% concentration. At last, these findings inform people that the weeds extract, especially &lt;i&gt;T. diversifolia&lt;/i&gt; is possible to be developed as bioinsecticides for &lt;i&gt;A. diaperinus&lt;/i&gt;.

Epidemiological and Bacteriological Investigations Using Whole-Genome Sequencing in a Recurrent Outbreak of Pullorum Disease on a Quail Farm in France

Simple Summary

Although pullorum disease is endemic in many parts of the world, this avian disease responsible for high economic and commercial losses has been eliminated from organized poultry production in Europe and North America. However, it may still remain in backyards and reappear sporadically on conventional poultry farms. This study presents in detail a recurrent outbreak of pullorum disease on a quail farm. In this case report, we present how epidemiological and bacteriological investigations using molecular sequencing tools were carried out in order to identify the source of contamination. Finally, we identify high-risk sanitary practices, and propose recommendations to manage and control this poultry disease, which has become rare in European countries. Given the development of outdoor farms and the increase in self-consumption family farms, a resurgence of pullorum disease cannot be excluded in the coming years. It is essential to develop effective sanitary barriers to prevent transmission between the two coexisting populations of commercial and non-commercial poultry and to raise awareness among all those involved in the poultry industry to be able to detect any outbreak quickly.

Abstract

An outbreak of pullorum disease causing septicemia and high mortality was diagnosed in 2019 on a quail farm in western France. An initial episode had been detected in another building at the same site eight months earlier. Given the exceptional nature and the extent of the potential economic consequences of pullorum disease, epidemiological and bacteriological investigations using molecular sequencing tools were carried out. Salmonella Gallinarum and Salmonella Infantis were isolated (using the NF U 47-101 reference method) from samples taken from birds at the infected site. A resurgence of the initial episode by horizontal transmission of S. Gallinarum is the most likely hypothesis, supported by whole-genome sequencing (WGS) of the strains isolated during the two episodes. Risk health practices have been identified, including the rearing of animals of different ages and species on the same site. Recurrence is explained by the probable persistence of reservoirs of the pathogen on the site (manure, lesser mealworm beetles). The article also highlights the importance of decontamination measures, including pest control, as a key element in the success of the disease control protocol.

Detection of Antimicrobial Resistant Salmonella enterica Strains in Larval and Adult Forms of Lesser Mealworm (Alphitobius diaperinus) From Industrial Poultry Farms

The lesser mealworms (Alphitobius diaperinus) constitute a common cosmopolitan pest in poultry flocks and may colonize the litter in adult and larval forms. Previous studies have documented their potential as carriers of enteric pathogens. In this context, S. enterica constitutes a prioritized zoonotic agent in the poultry industry due to the sanitary risks and economic losses associated with its presence. The aim of this study is to describe the presence of S. enterica strains in larval and adult forms of A. diaperinus collected from poultry litter belonging to industrial farms located in the central zone of Chile. A total of 403 specimens (203 adults and 200 larvae) were sampled from three farms and 25 flocks. For bacteriological isolation, beetles were processed to differentiate external and internal contamination. Then, isolates were serotyped according to the Kauffman-White scheme and antimicrobial resistance phenotypes were determined using the disk diffusion method. Gene sequences from the megaplasmid pESI were identified through a PCR based test. These procedures led to the detection of 15 S. enterica isolates, belonging to serotypes Infantis (14) and Livingstone (1), from both adults (6) and larval (9) specimens, with a similar external (7) and internal (8) distribution. Furthermore, all S. Infantis isolates showed antimicrobial resistance and evidence of megaplasmid pESI carriage, with all possessing multidrug-resistant phenotypes. Our results confirm that A. diaperinus constitutes a potential reservoir of zoonotic Salmonella strains of sanitary and economic concern for the industry and for public health.

Effectiveness of Biocidal Paint Containing Permethrin, Ultramarine and Violet 23 Against Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) in Laboratories and Poultry Houses

Reducing Alphitobius diaperinus in poultry production is a difficult task. However, attempts should be made to control the insect pest, as it poses a serious threat to the life and health of the chickens, as well as the workers on a farm. Our research was conducted in two stages to assess the effectiveness of the biocidal paint against A. diaperinus, containing active substances such as permethrin and a mixture of ultramarine and violet 23. In the first stage, under laboratory conditions, after 22 days, 100% mortality of A. diaperinus larvae and adults was achieved. This allowed us to assume that the biocidal paint may also be effective in poultry houses. In the poultry house where biocidal paint was applied, the number of insects decreased continuously alongside the sampling dates. In both research stages, the biocidal paint proved more effective against A. diaperinus than traditional limewash, and also the time to effective interaction of the paint was noted. Additionally, it was observed that the larvae were more susceptible to the active substances than adults. The research was practical, however, further analyses are necessary to fully control A. diaperinus, especially in poultry houses.

Salmonella Typhimurium Level in Mealworms (Tenebrio molitor) After Exposure to Contaminated Substrate

Findings of viable Salmonella spp., which are important foodborne pathogens, are seemingly not reported in mealworms (Tenebrio molitor) for feed and food. Still, the bacterial load of mealworms is naturally high and includes members of the Enterobacteriaceae family to which Salmonella belong. This indicates that Salmonella may be able to thrive in mealworms if introduced into the production. Therefore, this study aimed to assess the quantitative level of Salmonella enterica serovar Typhimurium (ST) in mealworms over a 14-day course after exposure to substrate contaminated with ST levels from 1.7 to 7.4 log CFU/g at start (i.e., day 0). The level of ST found in larvae was below the quantitative detection level (1 or 2 log CFU/g) on day 1 in larvae exposed to contamination levels of 1.7, 3.4, and 3.6 log CFU/g opposed to contamination levels of 5.4, 5.6, and 7.4 log CFU/g, respectively. The maximum level of ST detected in individual 1-g larvae samples was 5.8 log CFU/g, but the level varied among the triplicate samples from each sampling, and the highest average value was 5.3 ± 0.3. Beyond day 7, only larvae exposed to the contamination level of 7.4 log CFU/g were >1.0 log CFU/g in the triplicate samples. However, qualitative testing (10 g) showed the presence of ST in larvae until the end of the experiment on day 14 except for the lowest contamination level of 1.7 log CFU/g. Parallel testing of surface disinfected larvae indicated that some larvae may be ST-positive due to Salmonella residing on the surface only. Still, any detection of Salmonella is of concern from a food safety perspective. In substrate with contamination levels below 3.6 log CFU/g, the level of ST was below the quantitative detection limit within a few days. Still, ST was detected until the end of experiment on day 14 except for the lowest contamination level of 1.7 log CFU/g. This study indicates the importance of avoiding introduction of Salmonella into the production, e.g., via contaminated substrate in order to avoid Salmonella-positive larvae as they remained positive for at least 14 days (except at the lowest contamination level).

Population Growth of Alphitobius diaperinus (Coleoptera: Tenebrionidae) on Various Commodities

The lesser mealworm, Alphitobius diaperinus (Panzer), is a serious pest, but at the same time has been authorized in European Union (EU) for feed in aquaculture. In this study, we investigated, in laboratory bioassays, the population growth of this species, on a wide variety of commodities. In four series of bioassays, we studied the development of A. diaperinus population on various intact cereal grains, on soft wheat grains with different percentages of cracked kernels, on non-grain amylaceous commodities and on a variety of non-amylaceous commodities. Briefly, 20 g of each commodity were put separately inside plastic cylindrical vials. Then, 20 A. diaperinus adults were placed inside each vial and all vials were incubated at 30°C and 55% r.h. After 30 d, the vials were opened and the progeny production was evaluated. Alphitobius diaperinus showed a clear preference in amylaceous commodities, but in contrast, poor development was recorded on the non-amylaceous commodities tested. Hence, it developed well in most of the cereal intact grains tested, with the hard and soft wheat being the most suitable. Additionally, most non-grain amylaceous commodities were suitable, to a various degree, for the population growth of A. diaperinus. The increase of the percentage of cracked wheat positively affected the population growth of A. diaperinus. To our knowledge, this is the first study that examined the suitability of a wide range of commodities for the population growth of A. diaperinus.

Alphitobiusdiaperinus control and physicochemical study of poultry litters treated with quicklime and shallow fermentation

Poultry litter reuse in Brazil is a common practice to reduce broiler production costs. Quicklime and shallow fermentation treatments are methods used to reduce microbial contamination and infestation of insects such as Alphitobius diaperinus (Panzer). The aim of this study was to evaluate the physicochemical parameters of reused poultry litter to better characterize the effects of quicklime and shallow fermentation on Salmonella and A. diaperinus control. Ammonia and humidity concentrations significantly increased on the litter treated with shallow fermentation and pH when treated with virgin and hydrated quicklime. For A. diaperinus control, shallow fermentation with 2 and 3 L of water and 3 L plus 600g of quicklime/m² eliminated 100% of the insects. Results of assessed physicochemical parameters indicated that the treatments with quicklime and shallow fermentation are inefficient to control Salmonella spp. because they do not reach the indexes required for this pathogen elimination, mainly ammonia and pH. Ammonia index produced by microbial fermentation in shallow fermentation treatment eliminates A. diaperinus.