Ecotoxicity effect of aspirin on the larvae of Musca domestica through retinol metabolism.

Aspirin is a widely used multi-efficiency pharmaceutical, and its environmental residues are frequently detected. However, limited information is available on its effects on the development of the public health pest and saprophytic insect Musca domestica. In this study, it was demonstrated that aspirin inhibits the larval growth of house flies in a concentration-dependent manner. Microbiome analysis indicated that the composition of larval intestinal bacteria was influenced by aspirin but not greatly. The dominant bacterial genus in the aspirin group was still Klebsiella, as in the control group. Transcriptome sequencing and gene set enrichment analysis showed that retinol metabolism was activated after aspirin treatment. High performance liquid chromatography indicated that the content of retinol in larvae was decreased and that of retinoic acid was increased. The addition of ß-carotene, a precursor substance of retinol, in feeding promotes larval development and alleviates the inhibitory effect caused by aspirin. In contrast, retinoic acid delayed the larval development of house flies as well as aspirin. Gene expression analysis after aspirin exposure demonstrated that genes involved in the transformation from retinol to retinoic acid were upregulated. Overall, aspirin exposure impairs larval development by activating retinol metabolism in house flies and can be utilized as an effective pesticide. This work uncovers the mechanism underlying the larval development inhibition induced by aspirin in terms of metabolism and genetics, and provides novel functional exploration of a traditional drug for pest management.

Antagonistic effect of the beneficial bacterium Enterobacter hormaechei against the heavy metal Cu2+ in housefly larvae.

Vermicomposting via housefly larvae can be used to efficiently treat manure and regenerate biofertilizer; however, the uptake of heavy metals could negatively influence the growth and development of larvae. Intestinal bacteria play an important role in the development of houseflies, but their effects on resistance to heavy metal damage in houseflies are still poorly understood. In this study, the life history traits and gut microbiota of housefly larvae were evaluated after exposure to an environment with Cu2+ -Enterobacter hormaechei. The data showed that exposure to 300 µg/mL Cu2+ significantly inhibited larval development and locomotor activity and reduced immune capacity. However, dietary supplementation with a Cu2+ -Enterobacter hormaechei mixture resulted in increased body weight and length, and the immune capacity of the larvae returned to normal levels. The abundances of Providencia and Klebsiella increased when larvae were fed Cu2+ -contaminated diets, while the abundances of Enterobacter and Bacillus increased when larvae were exposed to a Cu2+ -Enterobacter hormaechei mixture-contaminated environment. In vitro scanning electron microscopy analysis revealed that Enterobacter hormaechei exhibited obvious adsorption of Cu2+ when cultured in the presence of Cu2+, which reduced the damage caused by Cu2+ to other bacteria in the intestine and protected the larvae from Cu2+ injury. Overall, our results showed that Enterobacter hormaechei can absorb Cu2+ and increase the abundance of beneficial bacteria, thus protecting housefly larvae from damage caused by Cu2+. These results may fill the gaps in our understanding of the interactions between heavy metals and beneficial intestinal bacteria, offering valuable insights into the interplay between housefly larvae and metal contaminants in the environment. This approach could enhance the efficiency of converting manure contaminated with heavy metals to resources using houseflies.

Presence of the toxigenic fungi Aspergillus spp. and Fusarium spp. in Musca domestica L. (Diptera: Muscidae) collected from dairy farms.

The objective of the study was to identify the presence of toxigenic fungi Aspergillus spp. and Fusarium spp. in domestic flies collected from dairy farms. We selected 10 dairy farms distributed in the central valley of the state of Aguascalientes, México. The flies were trapped using entomological traps with an olfactory attractant in 7 sites of the farm (silo-cutting surface, feed store, milking parlor, 3 feeders, and the rearing room). The fungi were cultivated in Sabouraud agar through direct sowing by serial dilutions to obtain the isolates, and a taxonomical identification was carried out under the microscope. The aflatoxins and zearalenone production capacity of the pure isolates were quantified using the ELISA test. The flies were present in all of the capture sites (45.3 flies, 567 mg, trap per day). We obtained 50 isolates of Aspergillus spp. genus, 12 of which produced aflatoxins (327 ± 143 µg/kg), whereas from 56 of the Fusarium spp. isolates, 10 produced large quantities of zearalenone (3,132 ± 665 µg/kg). These results suggest that the presence of domestic flies on dairy farms can constitute a source of dissemination for toxigenic fungi that can eventually contaminate grains and forage that are part of the daily cattle diet.

Effects of habitat and sampling time on bacterial community composition and diversity in the gut of the female house fly, Musca domestica Linnaeus (Diptera: Muscidae).

Adult house flies feed and breed in a variety of microbe-rich habitats and serve as vectors for human and animal pathogens. To better understand their role in harbouring and disseminating bacteria, we characterized the composition and diversity of bacterial communities in the gut of female house flies collected from three different habitats in Kansas: agricultural (dairy farm), urban (business area dumpsters) and mixed (business located between residential and animal agriculture areas). Bacterial community composition and diversity were influenced more by the house flies' habitat than by sampling time. The most abundant taxa were also highly prevalent in the house flies collected from all three habitats, potentially representing a 'core microbiome' attributable to the fly's trophic and reproductive associations with substrates and food sources comprised of decaying matter and/or animal waste. Bacterial taxa associated with vertebrate guts/faeces and potential pathogens were highly abundant in agricultural fly microbial communities. Interestingly, taxa of potential pathogens were highly abundant in flies from the mixed and urban sites. House flies harboured diverse bacterial communities influenced by the habitat in which they reside, including potential human and animal pathogens, further bolstering their role in the dissemination of pathogens, and indicating their utility for pathogen surveillance.

Flies as a potential vector of selected alert pathogens in a hospital environment.

Multi-drug resistant pathogens are a global problem. Flies are a potential vector of multi-drug resistant pathogens, which can be particularly dangerous in the hospital environment. This study aimed to evaluate flies as vectors of alert pathogens. The research material consisted of 100 flies (Musca domestica (46.0%), Lucilia sericata (28.0%), and Calliphora vicina (26.0%)) collected at the University Hospital No. 1 dr. A. Jurasz in Bydgoszcz (Poland) in 2018-2019 (summer months). The presence of bacteria of the genera: Enterococcus, Staphylococcus, Escherichia, Leclercia, Citrobacter, Hafnia, Providencia, Proteus, Enterobacter, Klebsiella, Raoultella, Morganella, Moellerella, Bordetella, Pantoea, Serratia, Plesiomonas, Wohlfahrimonas, and Lelliottia was confirmed. The most frequently isolated species included: Enterococcus faecalis (n = 64), Escherichia coli (n = 43) and Moellerella wisconsensis (n = 24). The infection rate and antibiotic resistance of bacteria were assessed. One strain of Proteus mirabilis (isolated from Calliphora vicina) produced ESBLs (extended-spectrum beta-lactamases). The infection rate was 0.38%, 0.26%, and 0.20% for Musca domestica, Lucilia sericata, and Calliphora vicina, respectively. The flies from a hospital area were not a vector of alert pathogens. Monitoring flies as potential vectors of pathogens is an important aspect of public health, especially for hospitalized patients.

Cantaloupe Facilitates Salmonella Typhimurium Survival Within and Transmission Among Adult House Flies (Musca domestica L.).

Salmonella enterica serovar Typhimurium is a pathogen harbored by livestock and shed in their feces, which serves as an acquisition source for adult house flies. This study used a green fluorescent protein (GFP) expressing strain of Salmonella Typhimurium to assess its acquisition by and survival within house flies, and transmission from and between flies in the presence or absence of cantaloupe. Female house flies were exposed to manure inoculated with either sterile phosphate-buffered saline or GFP-Salmonella Typhimurium for 12 h, then used in four experiments each performed over 24 h. Experiment 1 assessed the survival of GFP-Salmonella Typhimurium within inoculated flies. Experiment 2 determined transmission of GFP-Salmonella Typhimurium from inoculated flies to cantaloupe. Experiment 3 assessed fly acquisition of GFP-Salmonella Typhimurium from inoculated cantaloupe. Experiment 4 evaluated transmission of GFP-Salmonella Typhimurium between inoculated flies and uninoculated flies in the presence and absence of cantaloupe. GFP-Salmonella Typhimurium survived in inoculated flies but bacterial abundance decreased between 0 and 6 h without cantaloupe present and between 0 and 6 h and 6 and 24 h with cantaloupe present. Uninoculated flies acquired GFP-Salmonella Typhimurium from inoculated cantaloupe and bacterial abundance increased in cantaloupe and flies from 6 to 24 h. More uninoculated flies exposed to inoculated flies acquired GFP-Salmonella Typhimurium when cantaloupe was present than when absent. We infer that the presence of a shared food source facilitated the transfer of GFP-Salmonella Typhimurium from inoculated to uninoculated flies. Our study demonstrated that house flies acquired, harbored, and excreted viable GFP-Salmonella Typhimurium and transferred bacteria to food and each other. Understanding the dynamics of bacterial acquisition and transmission of bacteria between flies and food helps in assessing the risk flies pose to food safety and human health.

Apibacter muscae sp. nov., a novel bacterial species isolated from house flies.

We describe the isolation and characterization of three bacterial isolates from the common house fly, Musca domestica, caught in Londerzeel, Belgium and Huye District, Rwanda. Although isolated from distinct geographical locations, the strains show >99 % identical 16S rRNA gene sequences and are <95 % identical to type strains of Apibacter species. Whole-genome sequences were obtained for all three strains. The genomes are 2.4-2.5 Mb with a G+C content of ~30.3 mol%. Bacteriological and biochemical analysis of the strains demonstrate distinctly different characteristics compared to known Apibacter species. Particularly, the three strains investigated in this study can be distinguished from the known Apibacter species (Apibacter mensalisand Apibacter adventoris) through urease and ß-glucosidase activities. Whole-cell fatty acid methyl ester analysis shows that the fatty acid composition of the novel strains is also unique. On the basis of phylogenetic, genotypic and phenotypic data, we propose to classify these isolates as representatives of a novel species of the genus Apibacter, Apibacter muscae sp. nov., in reference to its prevalence in house flies, with strain G8T (=LMG 30898T=DSM 107922T) as the type strain.

The Potential Role of Synanthropic Rodents and Flies in the Transmission of Enterocytozoon bieneusi on a Dairy Cattle farm in China.

Enterocytozoon bieneusi causes microsporidiosis, a condition with complex epidemiology involving both direct and indirect transmission routes. To assess the potential role of synanthropic rodents and flies in the transmission of this pathogen, a total of 277 cattle fecal samples, 199 synanthropic rodents, and 50 batches of 20 flies were collected from a cattle farm. These samples were screened for the presence of E. bieneusi by PCR and sequencing of the internal transcribed spacer (ITS) region of the rRNA gene. The positive rates of cattle, synanthropic rodents, and flies were 11.9% (33/277), 4.0% (8/199) and 12.0% (6/50), respectively. Nineteen genotypes were identified, including 11 known genotypes (BEB6, I, COS-I, EbpC, D, J, CHS5, CHG1 to CHG3 and CHG14) and eight novel genotypes (named CHC9 to CHC16). The dominant genotype detected in the present study, BEB6, was found in all three categories of hosts. Moreover, human pathogenic genotypes D and EbpC were also observed in both synanthropic rodents and flies. These results demonstrate that synanthropic rodents and flies may act as biological disseminator or mechanical vector in the transmission of microsporidiosis to humans. Efforts should be made to minimize threats from these commensal animals to public health.

Housefly (Musca domestica) and Blow Fly (Protophormia terraenovae) as Vectors of Bacteria Carrying Colistin Resistance Genes.

Flies have the capacity to transfer pathogens between different environments, acting as one of the most important vectors of human diseases worldwide. In this study, we trapped flies on a university campus and tested them for mobile resistance genes against colistin, a last-resort antibiotic in human medicine for treating clinical infections caused by multidrug-resistant Gram-negative bacteria. Quantitative PCR assays we developed showed that 34.1% of Musca domestica (86/252) and 51.1% of Protophormia terraenovae (23/45) isolates were positive for the mcr-1 gene, 1.2% of M. domestica (3/252) and 2.2% of P. terraenovae (2.2%, 1/45) isolates were positive for mcr-2, and 5.2% of M. domestica (13/252) and 44.4% of P. terraenovae (20/45) isolates were positive for mcr-3 Overall, 4.8% (9/189) of bacteria isolated from the flies were positive for the mcr-1 gene (Escherichia coli: 8.3%, 4/48; Enterobacter cloacae: 12.5%, 1/8; Providencia alcalifaciens: 11.8%, 2/17; Providencia stuartii: 4.9%, 2/41), while none were positive for mcr-2 and mcr-3 Four mcr-1-positive isolates (two P. stuartii and two P. alcalifaciens) from blow flies trapped near a dumpster had a MIC for colistin above 4 mg/ml. This study reports mcr-1 carriage in Providencia spp. and detection of mcr-2 and mcr-3 after their initial identification in Belgium and China, respectively. This study suggests that flies might contribute significantly to the dissemination of bacteria, carrying these genes into a large variety of ecological niches. Further studies are warranted to explore the roles that flies might play in the spread of colistin resistance genes.IMPORTANCE Antimicrobial resistance is recognized as one of the most serious global threats to human health. An option for treatment of the Gram-negative ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) bacteria with multiple drug resistance was the reintroduction of the older antibiotic colistin. However, a mobile colistin resistance gene (mcr-1) has recently been found to occur widely; very recently, two other colistin resistance genes (mcr-2 and mcr-3) have been identified in Belgium and China, respectively. In this study, we report the presence of colistin resistance genes in flies. This study also reports the carriage of colistin resistance genes in the genus Providencia and detection of mcr-2 and mcr-3 after their initial identification. This study will stimulate more in-depth studies to fully elucidate the transmission mechanisms of the colistin resistance genes and their interaction.

Can Escherichia coli fly? The role of flies as transmitters of E. coli to food in an urban slum in Bangladesh.

OBJECTIVE: To investigate the transmission of faecal bacteria by flies to food under natural settings. METHODS: Over a period of 2 months, paired (exposed and non-exposed) containers with cooked rice were placed on the ground in kitchen areas in an urban slum area in Dhaka, Bangladesh, and the numbers of flies landing on the exposed rice were counted. Following exposure, the surface of the rice was microbiologically and molecularly analysed for the presence of Escherichia coli and genes of diarrhoeagenic E. coli and Shigella strains. RESULTS: Rice was at greater risk (P < 0·001) of being contaminated with E. coli if flies landed on the rice than if no flies landed on the rice (odds ratio 5·4 (P < 0·001, 95% CI: 2·5-11·7). Mean contamination in exposed rice samples (n = 60) was 3·1 × 103 CFU/g (95% CI: 2·2 × 103-4·0 × 103). Furthermore, for approximately half of the observed fly landings, the average CFU per fly landing was >0·6 × 103 CFU. Genes of diarrhoeagenic E. coli and Shigella species were detected in 39 of 60 (65%) of exposed rice samples. Two fly species were identified: the common housefly (Musca domestica) and the oriental latrine fly (Chrysomya megacephala). CONCLUSION: Flies may transmit large quantities of E. coli to food under field settings. The findings highlight the importance of implementing control measures to minimise exposure of food to flies to ensure food safety. Fly control measures should be considered for the prevention of diarrhoeal diseases caused by E. coli.

Identification and characterization of a novel antimicrobial protein from the housefly Musca domestica.

Antimicrobial peptides/proteins are immune-related molecules that are widely distributed in bacteria, fungi, plants, invertebrates and higher animals. They have exhibited great potential to be developed into antimicrobial drugs. The housefly, Musca domestica, lives in a highly contaminated environment and has adapted a robust immune system against various pathogens. As an effort to search for new antimicrobial molecules in the housefly, we investigated the function of an uncharacterized gene firstly by confirming that its expression was induced by infection in M. domestica. The corresponding protein was then shown to have potent antimicrobial activity. Scanning Electron Microscopy data showed that treatment of C. albicans cells with the protein caused cell size decreasing and cell elongation. The results here suggest the protein a novel class of antimicrobial protein and provide new insights into the immunological mechanisms by which M. domestica combats invading C. albicans.

Effects of four commercial fungal formulations on mortality and sporulation in house flies (Musca domestica) and stable flies (Stomoxys calcitrans).

The house fly Musca domestica L. (Diptera: Muscidae) and stable fly Stomoxys calcitrans (L.) (Diptera: Muscidae) are major pests of livestock. Biological control is an important tool in an integrated control framework. Increased mortality in filth flies has been documented with entomopathogenic fungi, several strains of which are commercially available. Three strains of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae) and one strain of Metarhizium brunneum (Petch) (Hypocreales: Clavicipitaceae) were tested in commercial formulations for pathogenicity against house flies and stable flies. There was a significant increase in mortality of house flies with three of the formulations, BotaniGard® ES, Mycotrol® O, and Met52® EC, during days 4-9 in comparison with balEnce™ and the control. In stable flies, mortality rates were highest with Met52® EC, followed by Mycotrol® O, BotaniGard® ES and, finally, balEnce™. There was a significant fungal effect on sporulation in both house flies and stable flies. Product formulation, species differences and fungal strains may be responsible for some of the differences observed. Future testing in field situations is necessary. These commercial biopesticides may represent important tools in integrated fly management programmes.

Cuticle hydrolysis in four medically important fly species by enzymes of the entomopathogenic fungus Conidiobolus coronatus.

Entomopathogenic fungi infect insects via penetration through the cuticle, which varies remarkably in chemical composition across species and life stages. Fungal infection involves the production of enzymes that hydrolyse cuticular proteins, chitin and lipids. Host specificity is associated with fungus-cuticle interactions related to substrate utilization and resistance to host-specific inhibitors. The soil fungus Conidiobolus coronatus (Constantin) (Entomophthorales: Ancylistaceae) shows virulence against susceptible species. The larvae and pupae of Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae), Calliphora vomitoria (Linnaeus), Lucilia sericata (Meigen) (Diptera: Calliphoridae) and Musca domestica (Linnaeus) (Diptera: Muscidae) are resistant, but adults exposed to C. coronatus quickly perish. Fungus was cultivated for 3 weeks in a minimal medium. Cell-free filtrate, for which activity of elastase, N-acetylglucosaminidase, chitobiosidase and lipase was determined, was used for in vitro hydrolysis of the cuticle from larvae, puparia and adults. Amounts of amino acids, N-glucosamine and fatty acids released were measured after 8 h of incubation. The effectiveness of fungal enzymes was correlated with concentrations of compounds detected in the cuticles of tested insects. Positive correlations suggest compounds used by the fungus as nutrients, whereas negative correlations may indicate compounds responsible for insect resistance. Adult deaths result from the ingestion of conidia or fungal excretions.

Brevibacillus laterosporus pathogenesis and local immune response regulation in the house fly midgut.

The insect midgut represents the primary site of action of the entompathogenic bacterium Brevibacillus laterosporus. While most studies on this microorganism focus on the identification and characterization of possible virulence factors and toxins, little is known about the insect immune defense mechanisms that are activated against this pathogen. In this study we have investigated the local immune response of different house fly stages to B. laterosporus at the transcriptional level, and we tested the hypothesis that an improvement in entomopathogenicity can be achieved by impairing host innate immunity. Gene expression analyses showed that immediately after spore ingestion (6-12h) both larvae and adults increased the transcription rate of immune related genes in the midgut tissues, with special regard to those encoding for the main house fly antimicrobial peptides (AMPs) (i.e., attacin, cecropin, defensin, diptericin, domesticin, muscin) and for prophenoloxydase that is normally involved in the cascade of events leading to the generation of reactive oxygen species (ROS) and other factors with antibacterial properties. In experiments evaluating the use of an immunosuppressive agent to enhance the virulence of B. laterosporus against adult house flies, a significant downregulation of the same genes was observed 12-24h after the administration of sub-lethal doses of the botanical compound azadirachtin. Consequently, a significant increase in B. laterosporus entomopathogenic action was observed when flies were preliminarily or simultaneously exposed to a sub-lethal dose of azadirachtin. These results provide an important contribution to the prospect of employing immune-impairing tools to implement pest management strategies.

Significance and Roles of Proteus spp. Bacteria in Natural Environments.

Proteus spp. bacteria were first described in 1885 by Gustav Hauser, who had revealed their feature of intensive swarming growth. Currently, the genus is divided into Proteus mirabilis, Proteus vulgaris, Proteus penneri, Proteus hauseri, and three unnamed genomospecies 4, 5, and 6 and consists of 80 O-antigenic serogroups. The bacteria are known to be human opportunistic pathogens, isolated from urine, wounds, and other clinical sources. It is postulated that intestines are a reservoir of these proteolytic organisms. Many wild and domestic animals may be hosts of Proteus spp. bacteria, which are commonly known to play a role of parasites or commensals. However, interesting examples of their symbiotic relationships with higher organisms have also been described. Proteus spp. bacteria present in soil or water habitats are often regarded as indicators of fecal pollution, posing a threat of poisoning when the contaminated water or seafood is consumed. The health risk may also be connected with drug-resistant strains sourcing from intestines. Positive aspects of the bacteria presence in water and soil are connected with exceptional features displayed by autochthonic Proteus spp. strains detected in these environments. These rods acquire various metabolic abilities allowing their adaptation to different environmental conditions, such as high concentrations of heavy metals or toxic substances, which may be exploited as sources of energy and nutrition by the bacteria. The Proteus spp. abilities to tolerate or utilize polluting compounds as well as promote plant growth provide a possibility of employing these microorganisms in bioremediation and environmental protection.

Vibrio cholerae laboratory infection of the adult house fly Musca domestica.

The present study was designed to test the hypothesis that house flies may be capable of specifically harbouring ingested Vibrio cholerae in their digestive tracts. Flies were continuously fed green fluorescent protein (GFP)-labelled, non-O1/non-O139 environmental strains of V. cholerae. Bacterial burdens were quantitatively measured using plate counts and localization was directly observed using confocal microscopy. Vibrio cholerae were present in the fly alimentary canal after just 4 h, and reached a plateau of ∼107 colony-forming units (CFU)/fly after 5 days in those flies most tolerant of the pathogen. However, individual flies were resistant to the pathogen: one or more flies were found to carry < 180 V. cholerae CFU at each time-point examined. In flies carrying V. cholerae, the pathogen was predominantly localized to the midgut rather than the rectal space or crop. The proportion of house flies carrying V. cholerae in the midgut was dose-dependent: the continuous ingestion of a concentrated, freshly prepared dose of V. cholerae increased the likelihood that fluorescent cells would be observed. However, V. cholerae may be a transient inhabitant of the house fly. This work represents the first demonstration that V. cholerae can inhabit the house fly midgut, and provides a platform for future studies of host, pathogen and environmental mediators of the successful colonization of this disease vector.

Dose-dependent fate of GFP-expressing Escherichia coli in the alimentary canal of adult house flies.

The adult house fly Musca domestica (L.) (Diptera: Muscidae) can disseminate bacteria from microbe-rich substrates to areas in which humans and domesticated animals reside. Because bacterial abundance fluctuates widely across substrates, flies encounter and ingest varying amounts of bacteria. This study investigated the dose-dependent survival of bacteria in house flies. Flies were fed four different 'doses' of green fluorescent protein (GFP)-expressing Escherichia coli (GFP E. coli) (very low, low, medium, high) and survival was determined at 1, 4, 10 and 22 h post-ingestion by culture and epifluorescent microscopy. Over 22 h, the decline in GFP E. coli was significant in all treatments (P < 0.04) except the very low dose treatment (P = 0.235). Change in survival (ΔS) did not differ between flies fed low and very low doses of bacteria across all time-points, although ΔS in both treatments differed from that in flies fed high and medium doses of bacteria at several time-points. At 4, 10 and 22 h, GFP E. coli ΔS significantly differed between medium and high dose-fed flies. A threshold dose, above which bacteria are detected and destroyed by house flies, may exist and is likely to be immune-mediated. Understanding dose-dependent bacterial survival in flies can help in predicting bacteria transmission potential.

Larvicidal activity and effects on post embrionary development of laboratory reared Musca domestica (Linnaeus, 1758) (Diptera: Muscidae), treated with Brevibacillus laterosporus (Laubach) spore suspensions.

The application of a spore suspension of Brevibacillus laterosporus (Laubach) (strain Bon707), at a concentration of 1.94×10(9)CFU/mL in the diet, induced a level of 70% mortality in larvae of Musca domestica. No sublethal effects, upon feeding activity or development were recorded. However, electron microscopic examination of the digestive tract of larvae fed with B. laterosporus, revealed cellular vacuolization and cytoplasmic disorganization.

Ecological study on antimicrobial-resistant zoonotic bacteria transmitted by flies in cattle farms.

Flies were qualitatively and quantitatively monitored on both livestock animals and the surrounding environment to investigate their role as a potential carrier for antimicrobial-resistant bacteria of zoonotic importance in cattle farms. This was done by the use of visual observations and animal photography; meanwhile, in the surrounding environment, flies were collected using sticky cards and then microscopically identified. Representative fly samples were cultured for bacterial isolation, biochemical identification, and then tested against common 12 antibiotics. The total average of dipterous flies in examined farms was 400.42 ± 6.2. Culicoides biting midges were the most common existing species (70.01 %) followed by house flies, stable flies, and mosquitoes (18.31, 7.74, and 3.91 %, respectively) at X (2) = 9.0, P < 0.05. The most predominant bacterial isolates were Escherichia coli (22.6 %), Staphylococcus aureus and Enterobacter (17.3 % each), coagulase-negative Staphylococci (CNS) (14.7 %), Klebsiella sp. (8 %), Salmonella spp. (6.7 %), and Shigella spp. and Proteus spp. (6.7 % each). The tested bacterial isolates were resistant to variant antibiotics used. S. aureus exhibited 100 % resistance to colistine. However, E. coli revealed 92.9 and 78.6 % resistance against tetracycline and colistine, respectively. Both Salmonella spp. and Shigella spp. were 100 % resistant to penicillin, and Klebsiella sp. had 100 % resistance to tetracycline. In conclusion, Culicoides biting midges and house flies could be considered as a potential carrier for multi-drug-resistant bacteria of zoonotic importance. Furthermore, cows' environment has an essential role in propagation and wide spread of antimicrobial-resistant bacterial pathogens.

Bacterial Associations Across House Fly Life History: Evidence for Transstadial Carriage From Managed Manure.

House flies (Diptera: Muscidae; Musca domestica L.) associate with microbe-rich substrates throughout life history. Because larvae utilize bacteria as a food source, most taxa present in the larval substrate, e.g., manure, are digested or degraded. However, some species survive and are present as third-instar larvae begin pupation. During metamorphosis, many bacteria are again lost during histolysis of the larval gut and subsequent remodeling to produce the gut of the imago. It has been previously demonstrated that some bacterial species survive metamorphosis, being left behind in the puparium, present on the body surface, or in the gut of the emerged adult. We used a combined culture-molecular approach to identify viable microbes from managed manure residue and a wild population of house fly larvae, pupae, puparia, and adults to assess transstadial carriage. All larval (10/10), pupal (10/10), and puparial (10/10) cultures were positive for bacteria. Several bacterial species that were present in larvae also were present either in pupae or puparia. Four viable bacterial species were detectable in 6 of 10 imagoes reared from manure. Of note is the apparent transstadial carriage of Bacillus sonorensis, which has been associated with milk spoilage at dairies, and Alcaligenes faecalis, which can harbor numerous antibiotic resistance genes on farms. The potential of newly emerged flies to harbor and disseminate bacteria from managed manure on farms is an understudied risk that deserves further evaluation.