Livestock Environment Research Articles

Swine farming shifted the gut antibiotic resistome of local people

Antibiotic resistance genes (ARGs) are prevalent in the livestock environment, but little is known about impacts of animal farming on the gut antibiotic resistome of local people. Here we conducted metagenomic sequencing to investigate gut microbiome and resistome of residents in a swine farming village as well as environmental relevance by comparing with a nearby non-farming village. Results showed a shift of gut microbiome towards unhealthy status in the residents of swine farming village, with an increased abundance and diversity in pathogens and ARGs. The resistome composition in human guts was more similar with that in swine feces and air than that in soil and water. Mobile gene elements were closely associated with the prevalence of gut resistome. Some plasmid-borne ARGs were colocalized in similar genetic contexts in gut and environmental samples. Metagenomic binning obtained 47 ARGs-carrying families in human guts, and therein Enterobacteriaceae posed the highest threats in antibiotic resistance and virulence. Several ARGs-carrying families were shared by gut and environmental samples (mainly in swine feces and air), and the ARGs were evolutionarily conservative within genera. The findings highlight that swine farming can shape gut resistome of local people with close linkage to farm environmental exposures.

The Quality of Dairy Cow Bedding and the Occurrence of Environmental Mastitis: Review

An excessive incidence of inflammation of the mammary glands of dairy cows has been observed in many dairy farms in the past, which has been demonstrably correlated with an increased incidence of microbial pathogens in livestock environments. The causes of mastitis can be infectious or non-infectious in nature, one of the main sources of this disease is litter material in the lager. The issue of mastitis has a significant impact on the economic value of dairy cows and therefore it is necessary to create effective measures that eliminate the appearance of pathogenic microorganisms. In this respect, litter material obtained by physical separation and thermal treatment of slurry may represent a suitable alternative ensuring inhibition of the development of dangerous bacteria while maintaining the comfort of dairy cows. Current evidence on the safety and benefits of such material is limited and data on effects on clinical and/or subclinical mastitis are insufficient. In this review, therefore, we would like to shed light on the onset of mastitis in dairy cows and point out possible procedures for treating slurry in practice.

Evaluation of CCHF Infection in Hard Ticks in Razavi Khorasan Province, Iran

Background: Crimean-Congo hemorrhagic fever (CCHF) is a potentially fatal tick-borne viral disease. Hard ticks are both carriers and reservoirs of the CCHF virus. In this regard, the present study was done to investigate the CCHF viral infection in collected ticks from livestock in Gonabad City (Southwest of Razavi Khorasan Province) in Eastern Iran. Methods: This descriptive study was performed in rural areas of Gonabad City in 2018. The forceps sampling method collected hard ticks from livestock (goats, sheep, and cattle). The ticks were identified based on a valid taxonomic key; finally, the CCHF viral infection was evaluated using the RT-PCR technique. Results: Between April and October 2018, 100 ticks were collected from 13 rural areas of Gonabad. The frequency of ticks collected from goats, sheep, and cows was 6.4%, 3.7%, and 89.9%, respectively. Also, 90% of ticks were Hyalomma (Hyalomma anatolicum excavatum (n=9), Hyalomma lusitanicum (n=59), Hyalomma marginatum (n=4), Hyalomma anatolicuman (n=18)) and the remaining 10% were Rhipicephalus sanguine. Overally, CCHF infection was observed in 14% of the ticks (Hy. excavatum, Hy. lusitanicum, and Hy. anatolicumand Rhipicephalus sanguineus). Conclusion: Hyalomma species is the main vector of the CCHF virus. Due to the high abundance of hard ticks in nature and the livestock environment, special care is required in the villages. Also, due to the presence of more scattered ticks in the northern half of the country, comprehensive studies that cover a wide geographical area and cover a larger sample size are necessary.

Effectiveness equilibration time on the quality of sperm buffalo in diluent tris yolk eggs with 4 % extract skin mangosteen (Garcinia mangostana L.)

A comfortable livestock environment will produce good sperm productivity. Sperm dilution is done so that rural communities can feel the benefits. This study aims to determine the best equilibration time to produce high motility, intact plasma membrane values with low abnormality values in buffalo spermatozoa. This research used a completely randomized design (CRD) with four treatments and ten replications. Sperm came from three buffalo kept at the Ciawi Balitnak. The research treatment consisted of equilibration times of two, three, four and five hours. The parameters measured were sperm motility, abnormality, and intact plasma membrane (IPM). Equilibrium time does not affect buffalo sperm motility, abnormalities, and IPM. The range of motility, abnormalities, and IPM was 43.75%-55.00%; 20.25%-29.00%; 71.75%-74.75%. Conclusion; An equilibration time of two hours can maintain motility, abnormality, the intact plasma membrane of buffalo sperm with egg yolk tris diluent, and the addition of 4% mangosteen peel extract which was suitable for artificial insemination. The application can improve the standard of living of the community through increased meat production.

Methionine influences the profile of intestinal antibiotic resistome through inhibiting the growth of Escherichia coli

Antibiotic resistance genes (ARGs) are a new type of environmental pollutant. However, studies have mainly focused on the distribution characteristics of ARGs in the livestock environment, lacking of studies on the composition of ARGs in the intestinal tract of animals and the effect of nutrients on intestinal ARGs and microbial communities. Reducing antimicrobial resistance and maintaining optimal animal health and performance are urgently needed. Methionine is an essential amino acid which plays a critical role in the growth and reproductive performance of animals. In this study, feeding experiment, in vitro fermentation and bacterial culture experiment were performed to explore the influence of methionine on the intestinal resistome of sows. We found that dietary 0.2 % methionine supplementation decreased the total abundance of intestinal ARGs, which was further confirmed by in vitro fecal microbial fermentation of sows. Metagenome binning analysis identified that Escherichia coli was the major ARG host, which carried 60–113 ARGs and 134–286 virulence factors, indicating that Escherichia coli in the pig intestine is not only a core ARG host, but also an important pathogen. In addition, we found that methionine supplementation inhibited the growth of Escherichia coli, indicating that dietary methionine may reduce the resistome risk in sow intestine by inhibiting core ARG hosts such as Escherichia coli. These findings reveal that dietary methionine application plays a critical role in intestinal antibiotic resistance, providing a new idea for preventing and controlling environmental pollution by antibiotic-resistant microbes.

Analysis on Coupling Coordination Degree for Cropland and Livestock from 2000 to 2020 in China

The decoupling of cropland and livestock due to the industrialization of livestock production is a difficult problem for sustainable agricultural development in many global locations, including China. As population and urbanization increase, this decoupling is likely to become more serious. To date, the relationship between cropland and livestock has been mainly studied from a single perspective, and mostly at the regional and the local scales. Thus, the objective of our study is to systematically assess the coupling relationship between cropland and livestock from multiple aspects on a large scale. Here, we used a complex system covering cropland, livestock and environment subsystems to comprehensively analyze the spatio-temporal variation of the coupling coordination between cropland and livestock and its influencing factors in China over the past two decades. Elaborating on the data, we constructed a comprehensive system of evaluation indexes for cropland–livestock systems. We used a coupling coordination degree model to evaluate the coupling coordination relationship between cropland and livestock in 31 provinces of China during 2000–2020. The results show that the range of cropland–livestock and cropland–livestock–environment coupling coordination degree was 0.4–0.9. In most of the provinces, there was no risk of cropland and livestock decoupling; however, the coupling coordination degree needed to be increased. More attention should be paid to the coordinated development of cropland and livestock coupling in urbanized areas such as Beijing and Tianjin, where cropland and livestock decoupling was more likely to occur. Among the assessed 29 factors, 15 and 16 had an impact on the cropland–livestock and the cropland–livestock–environment coupling coordination degrees, respectively. Our study provides science-based evidence to support estimating the coupling relationship between cropland and livestock in the future.

Progress in the Prevalence, Classification and Drug Resistance Mechanisms of Methicillin-Resistant Staphylococcus aureus.

Staphylococcus aureus is a common human pathogen with a variety of virulence factors, which can cause multiple infectious diseases. In recent decades, due to the constant evolution and the abuse of antibiotics, Staphylococcus aureus was becoming more resistant, the infection rate of MRSA remained high, and clinical treatment of MRSA became more difficult. The genetic diversity of MRSA was mainly represented by the continuous emergence of epidemic strains, resulting in the constant changes of epidemic clones. Different classes of MRSA resulted in different epidemics and resistance characteristics, which could affect the clinical symptoms and treatments. MRSA had also spread from traditional hospitals to community and livestock environments, and the new clones established a relationship between animals and humans, promoting further evolution of MRSA. Since the resistance mechanism of MRSA is very complex, it is important to clarify these resistance mechanisms at the molecular level for the treatment of infectious diseases. We firstly described the diversity of SCCmec elements, and discussed the types of SCCmec, its drug resistance mechanisms and expression regulations. Then, we described how the vanA operon makes Staphylococcus aureus resistant to vancomycin and its expression regulation. Finally, a brief introduction was given to the drug resistance mechanisms of biofilms and efflux pump systems. Analyzing the resistance mechanism of MRSA can help study new anti-infective drugs and alleviate the evolution of MRSA. At the end of the review, we summarized the treatment strategies for MRSA infection, including antibiotics, anti-biofilm agents and effluxpump inhibitors. To sum up, here we reviewed the epidemic characteristics of Staphylococcus aureus, summarized its classifications, drug resistance mechanisms of MRSA (SCCmec element, vanA operon, biofilm and active efflux pump system) and novel therapy strategies, so as to provide a theoretical basis for the treatment of MRSA infection.

Swine farm groundwater is a hidden hotspot for antibiotic-resistant pathogenic Acinetobacter

Acinetobacter is present in the livestock environment, but little is known about their antibiotic resistance and pathogenic species in the farm groundwater. Here we investigated antibiotic resistance of Acinetobacter in the swine farm groundwater (JZPG) and residential groundwater (JZG) of a swine farming village, in comparison to a nearby (3.5 km) non-farming village (WTG) using metagenomic and culture-based approaches. Results showed that the abundance of antibiotic resistome in some JZG and all JZPG (~3.4 copies/16S rRNA gene) was higher than that in WTG (~0.7 copies/16S rRNA gene), indicating the influence of farming activities on both groundwater types. Acinetobacter accounted for ~95.7% of the bacteria in JZG and JZPG, but only ~8.0% in WTG. They were potential hosts of ~95.6% of the resistome in farm affected groundwater, which includes 99 ARG subtypes against 23 antibiotic classes. These ARGs were associated with diverse intrinsic and acquired resistance mechanisms, and the predominant ARGs were tetracyclines and fluoroquinolones resistance genes. Metagenomic binning analysis elucidated that non-baumannii Acinetobacter including A. oleivorans, A. beijerinckii, A. seifertii, A. bereziniae and A. modestus might pose environmental risks because of multidrug resistance, pathogenicity and massive existence in the groundwater. Antibiotic susceptibility tests showed that the isolated strains were resistant to multiple antibiotics including sulfamethoxazole (resistance ratio: 96.2%), levofloxacin (42.5%), gatifloxacin (39.0%), ciprofloxacin (32.6%), tetracycline (32.0%), doxycycline (29.0%) and ampicillin (12.0%) as well as last-resort polymyxin B (31.7%), colistin (24.1%) and tigecycline (4.1%). The findings highlight potential prevalence of groundwater-borne antibiotic-resistant pathogenic Acinetobacter in the livestock environment.

The Care of Environment in the Characters Pandawa of Mahabrata's Story: The Study of Literature Ecology

This writing examines a non-fiction prose by using the study of literary ecology. Literary ecology is a study related to the environment that arises from the results of thinking about ecological problems in literature. This writing aims to describe the Pandawa character's attention to the environment, the form of the Pandawa character's concern for the environment, and the interaction of the Pandawa character towards the environment in the Mahabharata story. The formulation of the problem in this writing is as follows, namely (1) How is the concern of the Pandawa character towards the environment depicted in the Mahabharata story?; (2) What is the form of the Pandawa character's concern for the environment described in the Mahabharata story?; and (3) How is the interaction between Pandawa figures and the environment described in the Mahabharata story? This type of research is a qualitative literature study model using an ecological literature approach. The main focus in this research is to describe the environmental care attitude of the pandawa character in the Mahabharata story. The data source is the text of the Mahabharata transliterated by C. Rajagopalacari. The data are in the form of words, phrases, dialogues, and sentences in the Mahabharata story which contain attention, forms of concern, and interactions of Pandawa characters towards the environment. Data collection using documentation techniques. Data analysis using interactive analysis techniques. The results of the discussion show the concern of the Pandawa characters for the environment, namely Nakula and Sadewa for livestock, there is a form of concern for the Pandawa characters for the environment, namely rebuilding the abandoned old city, and the interaction between Pandawa figures and nature, namely using rivers and snake venom as an antidote to poison in the story. the.

Greenhouse Gas Emission in Italian Mediterranean Buffalo According to Two Different Feed Sources: Preliminary Study

Greenhouse gas emissions (GHG) in animal husbandry depend on several factors. Among the greenhouse gases, the methane (CH4) deriving from enteric fermentation and ammonia emissions is the ones that encounter the greatest attention in ruminant breeding. The study was conducted in the two farms located in southern Italy. To determine the enteric greenhouse gas emissions from buffalo, information about animal production and farm management was analysed and using the Global Livestock Environmental Assessment interactive mode (GLEAM-i). In this experiment, the buffalo were fed with two types of unifeed ad was calculated CO2, CH4 and N2O emission produced. The resulting values of GHG emission from each production system were analysed using the t - test procedure using SPSS® version 26. The dry forage diet system had the highest GHG emission compared to green forage diet system, indicating the effect of higher inputs in the dry system in increasing GHG emission. From the results, greener management using feed and other management inputs would not only improve productivity, but also reduce the contribution of livestock to global greenhouse gas emissions.

Contribution of Climate-Smart Forage and Fodder Production for Sustainable Livestock Production and Environment: Lessons and Challenges from Ethiopia

Sustainable farm animal raising is dependent on the production of sufficient quantities and quality of forages and fodder, especially in dry regions. Improved forage and feed species are an option for these aspects because adequate feed resources enhance soil health and carbon, generate income, and reduce emissions. Therefore, the purpose of this review paper was to investigate the role of climate-smart forage production in sustaining farm animal production and maintaining the environment in arid and semiarid regions. Seasonal fluctuations in feed supply cause temporal scarcity in Ethiopia, with more acute gaps in dry periods, particularly in drought-prone regions. To address these problems in the country, improve forages to strengthen farm productivity, climate change resilience, and environmental sustainability, particularly in arid and semiarid areas. The country has a long history and is of some exemplary practices in indigenous improved forage production, but the input of improved forage to the total biomass production in feed resources is still low due to many factors like scarcity of land and water for irrigation, lack of awareness, forage seed, and policy recommendations. Despite the potential profits of feed and forage grasses and legumes, the availability of species adapted to a wide range of situations in actual use in the livestock sector has been insufficient. Therefore, it is strongly suggested that climate-resilient forage species be popularized to sustain livestock production and the environment, particularly in the country’s arid and semiarid regions.

Emergence of Nontuberculous Mycobacteria at the Human–Livestock–Environment Interface in Zambia

The prevalence of nontuberculous mycobacteria (NTM) infections and disease is rising worldwide due to increased research, diagnostics capabilities, and awareness of the disease. There is limited prevalence data for NTM from different sources in Zambia. The aim of this study was to determine the prevalence and species distribution of NTM at the human–livestock–environment interface. A cross-section study was conducted in Namwala, Chipata, and Lundazi Districts of Zambia from April 2020 to December 2021. Sputum samples were collected from tuberculosis presumptive patients from different health centers, cattle tissues were collected from different abattoirs during routine post-mortem, and water samples were collected from different drinking points for humans and animals such as taps, boreholes, wells, rivers, dams and ponds, and then cultured following standard mycobacteriology procedures. Capilia TB-Neo assay was used to identify NTM from the positive cultures. DNA was extracted and the 16S to 23S rRNA (internal transcribed spacer region) (ITS) was amplified and sequenced to identify the species. The overall prevalence of NTM from humans, cattle, and water was 9.1% (72/794, 95% CI 7.2–11.3). The prevalence in humans was 7.8% (33/421, 95% CI 5.54–10.94), in cattle it was 10.6% (15/142, 95% CI 6.2–17.1), and in water it was 10.4% (24/231, 95% CI 6.9–15.2). Our study has shown, for the first time in Zambia, simultaneous isolation of NTM at the human–livestock–environment interface; M. avium complex and M. fortuitum were the most commonly isolated species. M. fortuitum and M. gordonae were isolated from all three sources, while M. abscessus was isolated from humans and water. The isolation of similar NTM species at the interface which are potentially pathogenic is a public health problem which merits further investigation.

Advanced contribution of IoT in agricultural production for the development of smart livestock environments

Many areas of contemporary life need the use of Artificial Intelligence (AI), Machine Learning (ML), and the Internet of Things (IoT) for analysis and comprehension. The application of AI and ML in livestock farming has led to an improved understanding of animal behavior and discomfort, the prevention and management of diseases, and the efficiency of the farmer's economic choices. Digital twin technology is a particularly promising field that builds on AI and is already being utilized to increase efficiency and decrease costs in cattle livestock agriculture. A Digital Twin (DT) is a constant-update numerical copy of smart livestock environments. The proposed research is IoT, and Digital Twins in Livestock Farming (DTLF) might expand extensive Precision Livestock Farming (PLF), technology and tools use, and farm animal health and well-being. Global Positioning Satellite (GPS), Radio Frequency IDentification (RFID), AI, and even ML are only some current technologies that may be used for automated tracking of individual animal whereabouts. There is promise in using these methods and innovations to monitor and evaluate animal welfare, but these techniques are difficult. Just like other revolutionary innovations, the utilization of the DT mechanism will improve disease analysis prediction for individual farms by a factor of 92%. The responsiveness of DTLF will be a 92% response rate in analyzing the Heartbeat, a 94% effectiveness rate in analyzing the Temperature Range, and a 94% overall effectiveness in evaluating the Humidity Range.

Fecal Microbiota of Rhinoceros Unicornis as a Reservoir of Multi-Drug-Resistant Bacteria

The presence of Antimicrobial Resistance (AMR) bacteria in wildlife indicates the possible role of wild animals as efficient AMR reservoirs and dispersers of resistant bacteria to the human, livestock and natural environments. The presence of AMR bacteria not only has serious public health consequences, but also threatens native wildlife populations. In this study, we investigate the occurrence and antibiotic resistance patterns of fecal microbiota of Rhinoceros unicornis in Assam. Sixty two freshly voided dung samples of rhinoceros were collected from Kaziranga National Park of Assam in 2018. Fecal samples were tested for the presence of bacterial species and submitted to National Centre for Veterinary Type Cultures, National Research Centre on Equines, (NC-VTCC, NRCE) Hisar for identification. Antimicrobial Susceptibility Testing (AST) was determined using the disk diffusion method and antibiotic resistance patterns were assessed according to the Clinical and Laboratory Standards Institute (CLSI) recommendations. Overall, 24 isolates were identified that belonged to 19 different bacterial genera including Klebsiella spp., Achromobacter spp., Pseudomonas spp., Alishewanella spp., Wautersiella spp., Moraxella spp., Inquilinus spp., Weeksella spp., Oligella spp., Myroides spp., Paracoccus spp., Ochrobactrum spp., Psychrobacter spp., Pannonibacter spp., Shewanella spp., Sphingobacterium spp., Sphingomonas spp. (4% each), Escherichia coli (8%) and Acinetobacter spp. (21%). Of the 24 isolates found in rhinoceros fecal samples tested for antimicrobial susceptibility, 13 isolates showed resistant to three or more than three substance classes. Results indicate that overall, most of the bacterial species from R. unicornis were multi-drug-resistant, which may reflect not only several risk factors leading to the origin of AMR in wild animals but also wildlife as natural reservoir of resistant bacteria. Therefore, efforts must be initiated to monitor the occurrence of such AMR bacteria in wildlife and understand their potential effect on wildlife conservation and public health.

Carbapenem resistance in Enterobacterales from agricultural, environmental and clinical origins: South Africa in a global context.

Carbapenem agents are regarded as last-resort antibiotics, however, bacterial resistance towards carbapenems has been reported in both clinical and agricultural settings worldwide. Carbapenem resistance, defined as the resistance of a bacteria towards one or more carbapenem drugs, can be mediated in either of, or a combination of, three mechanisms-although, the mechanism mediated through the production of carbapenemases (β-lactamases that are able to enzymatically degrade carbapenems) is of most significance. Of particular concern is the occurrence of carbapenemase producing Enterobacterales (CPE), with literature describing a dramatic increase in resistance globally. In South Africa, increases of carbapenemase activity occurring in Enterobacter species, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa have recently been reported. CPE can also be found in agricultural environments, as global studies have documented numerous instances of CPE presence in various animals such as pigs, cattle, seafood, horses and dogs. However, most reports of CPE occurrence in agricultural settings come from Northern America, Europe and some parts of Asia, where more extensive research has been conducted to understand the CPE phenomenon. In comparison to clinical data, there are limited studies investigating the spread of CPE in agricultural settings in Africa, highlighting the importance of monitoring CPE in livestock environments and the food chain. Further research is necessary to uncover the true extent of CPE dissemination in South Africa. This review will discuss the phenomenon of bacterial antibiotic resistance (ABR), the applications of the carbapenem drug and the occurrence of carbapenem resistance globally.

Contamination of Escherichia coli O157:H7 in Milk and Its Dairy Products in Depok, Cianjur, Sukabumi and Bandung

Escherichia coli O157:H7 is known as a foodborne pathogen that can infect humans as well as animals. Dairy cows are the main reservoir of E. coli O157:H7 strains. These bacteria have the potential to pollute milk through direct contact with cattle and the dairy farming environment. Bacteria can survive during the production process and dairy products such as cheese. The presence of E. coli O157:H7 in dairy products has not been widely reported in Indonesia. The purpose of this study was to examine E. coli O157:H7 in the fresh milk from livestock and dairy products obtained from supermarkets and traditional markets in Depok, Cianjur, Sukabumi, and Bandung. A conventional method for E. coli isolation and testing techniques and serotyping tests on O157 and H7 was used in the study. The results showed that 26 isolates (23.85%) of a total of 109 fresh milk samples were positive for E. coli. They were identified as E. coli O157:H7 were 17 (65.38%) of 26 E. coli isolates. In dairy products, E. coli O157:H7 was not detected. This indicates that biosafety and biosecurity in the of dairy cows need to be to prevent E. coli O157:H7 contamination in milk and their livestock environment.

Lab-based meat the future food

• Lab-based meat is more sustainable and safer to consume than conventional meat. • Production steps: cell extraction, cell line establishment, cell culture and scaffolding. • Challenges: technology limitations, consumer acceptance & law and legislation. Meat is one of the main dietary protein sources that is important in human health and development. Today, the rapid growth of the world's population has resulted in an increasing demand for meat sources worldwide. With the climate crisis devastating natural and agricultural resources, the Earth's ecosystems may no longer support an expanded traditional meat industry. At the same time, increasing meat production and consumption have raised issues regarding the environment, animal ethics, and human health. In line with the global sustainability trends, lab-based meat has been introduced in the last decade as a meat alternative. The production of lab-based meat required high-throughput technology at a wide scale to develop high-quality meat in the laboratory customized for the livestock agriculture industry, environment, animal welfare and human health. However, the development of laboratory-produced meat is still in its early stages, and it is currently confronted with significant challenges such as technological limitations and consumer acceptance. Therefore, there is no legal recognition of lab-based meat worldwide. Nevertheless, due to the trend for a high market demand for meat analogues, this field of study is expected to contribute to the company portfolio, thus more funding and research are required to ensure its safety and societal requirements.

Application strategy for sustainable livestock production with farm animal algorithms in response to climate change up to 2050: A review

Global warming caused by climate change can increase heat stress and greenhouse gas (GHG) emissions, leading to food problems and livestock crises. Thus, pre-emptive responses are required to mitigate the food problems and livestock crises. The potential of a livestock crisis caused by global warming highlights the need for sustainable livestock production in response to climate change using a farm animal algorithm in order to address the population increase and avoid food problems in the future. In particular, the demand for animal-based foods has increased. Such a climate change threatens the livestock environment, production, reproductive efficiency, animal behaviour and welfare, while increasing the heat stress, livestock malodours, and GHG emissions. For these reasons, it is necessary to understand the concurrent mechanisms related to these effects of global warming, animal nutrition, animal feeding and management, animal heat stress and in ovo injection, and carbon neutral livestock. Climate-smart livestock systems are being implemented to overcome the livestock crisis caused by climate change and to maintain sustainable livestock production. This review emphasises the importance of sustainable livestock production using farm animal algorithms in response to a future livestock crisis caused by climate change in 2050.

Erratum to: Evaluation of adenosine triphosphate testing for on-farm cleanliness monitoring compared to microbiological testing in an empty pig farrowing unit

[This corrects the article DOI: 10.5187/jast.2020.62.5.682.].

Exploring the nature of interaction between shiga toxin producing Escherichia coli (STEC) and free-living amoeba - Acanthamoeba sp

Free-living amoebae (FLA) are widely distributed protozoa in nature, known to cause severe eye infections and central nervous system disorders. There is growing attention to the potential role that these protozoa could act as reservoirs of pathogenic bacteria and, consequently, to the possibility that, the persistence and spread of the latter may be facilitated, by exploiting internalization into amoebae. Shiga toxin-producing strains of Escherichia coli (STEC) are zoonotic agents capable of causing serious diseases, such as hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Cattle represent the main natural reservoir of STEC, which are frequently found also in other domestic and wild ruminants, often without causing any evident symptoms of disease. The aspects related to the ecology of STEC strains in animal reservoirs and the environment are poorly known, including the persistence of these microorganisms within niches unfavorable to survival, such as soils or waters. In this study we investigated the interaction between STEC strains of serotype O157: H7 with different virulence gene profiles, and a genus of a wild free-living amoeba, Acanthamoeba sp. Our results confirm the ability of STEC strains to survive up to 20 days within a wild Acanthamoeba sp., in a quiescent state persisting in a non-cultivable form, until they reactivate following some stimulus of an unknown nature. Furthermore, our findings show that during their internalization, the E. coli O157 kept the set of the main virulence genes intact, preserving their pathogenetic potential. These observations suggest that the internalization in free-living amoebae may represent a means for STEC to resist in environments with non-permissive growth conditions. Moreover, by staying within the protozoa, STEC could escape their detection in the vehicles of infections and resist to the treatments used for the disinfection of the livestock environment.