BACKGROUND: Pigeons can be carriers for some human and animal pathogens, one of the most important of which is Escherichia coli. OBJECTIVES: This bacterium is responsible for outbreaks of many human diseases. Our objective was to determine the prevalence of Escherichia coli in cloacal area of pigeons in Tehran city (Iran), and determine  the prevalence of some virulence genes and also antibiotics resistance pattern of isolates. METHODS: Altogether 117 samples of pigeon feces were collected from cloacal swab. The identification of bacteria was done by culture on differential culture media. Then antibiotic susceptibility test was performed by disk diffusion method. Isolates were tested for the presence of virulence genes stx1, stx2, eae and hlyA using multiplex polymerase chain reaction. RESULTS: Escherichia coli were detected in 82.9% of 277 samples from pigeons. Sulfamethoxazole was the least effective drug (85.6% resistance), followed by tetracycline (83.5%). No resistance was detected to co-amoxiclav. The prevalence of stx1, stx2 and eaeA is 3.09%, 6.18% and 2.06% respectively and hlyA was not found in any of isolates. CONCLUSIONS: The frequency of stx1 and stx2 distribution in animals and birds is not well understood as yet. Due to the close relationship of humans with birds like pigeons and presence of STEC strains in apparently healthy birds, necessitates  considering  precise regulations to restrict and prevent the prevalence of this life- threatening virus in Iran.

BACKGROUND: Corynebacterium pseudotuberculosis is the etiological agent of caseous lymphadenitis (CLA), a chronic and very common disease in sheep and goats, which can lead to severe economic losses in the livestock industry.OBJECTIVES: This study aims to investigate the prevalence of CLA in sheep in Kurdistan province of Iran using phenotypic and molecular methods, and assess the antibiotic resistance of isolated Corynebacterium pseudotuberculosis.METHODS: In this study, from September to March 2022, 270 samples of skin abscesses were collected from sheep in livestock farms of Kurdistan province. Immediately, using the cold chain system, the samples were transferred to the microbiology laboratory of the Faculty of Medicine at Kurdistan University of Medical Sciences. Identification of isolates was done using biochemical tests and polymerase chain reaction (PCR) method. The antibiotic resistance of the isolates was examined using the Kirby-Bauer disk diffusion method.RESULTS: Based on biochemical tests, out of 270 samples, 82 suspected to have Corynebacterium pseudotuberculosis. Out 82 samples, the presence of bacteria was confirmed in 76 samples by the PCR. The antibiotic sensitivity test showed that the isolates had high sensitivity to doxycycline and ceftriaxone and high resistance to streptomycin and kanamycin.CONCLUSIONS: The CLA has a high prevalence in sheep in Kurdistan province. According to high resistance rate of Corynebacterium pseudotuberculosis to streptomycin and kanamycin, it recommended to avoid treatment of CLA cases with these antibiotics.

Antimicrobial resistance (AMR) is a global public health threat for both human and veterinary medicine. Increasing evidence suggests that animals are important sources of AMR to humans; however, most of these studies focus on production animals. In order to determine the pattern of AMR in pets, mainly in dogs in Africa, a meta-analysis was performed with AMR studies conducted in African countries and published between January 2000 and January 2021 in four databases: Medline (PubMed), Scopus, Cab abstract and Google Scholar. Seven bacterial strains, namely Staphylococcus aureus, Escherichia coli, Salmonella spp., Pseudomonas aeruginosa, Streptococcus pyogenes, coagulase-negative Staphylococcus (SNC) and Staphylococcus pseudintermedius were included in this study. A total of 18 out of 234 indexed articles met the study criteria. The results revealed that multiple bacteria were resistant to various commonly used antibiotics including enrofloxacin, ciprofloxacin, gentamicin, amoxicillin, clavulanic acid, cotrimoxazole, streptomycin, tetracycline and chloramphenicol. Concerning multidrug resistance, E. coli strains came first with the highest prevalence of 98%, followed by P. aeroginosa (92%) and Salmonella spp. (53%). In contrast, the overall prevalence of multidrug resistance was low for S. aureus (18%) and S. pseudintermedius (25%). It is therefore urgent to find, as soon as possible, alternatives to replace these antibiotics, which have become ineffective in controlling these bacteria in dogs in Africa. Moreover, further metagenomic studies are needed to describe the full resistome and mobilome in dogs regardless of the bacteria.

Antimicrobial resistance is currently one of the major public health threats. In order to prevent its spread, the WHO, OIE and FAO have formed an alliance to promote the study of antibiotic resistance evolution in human, animal and environmental bacteria posing a public health threat; however, the studies performed in wild animals are scarce so far. The main objective of this study was to assess the antibiotic resistance of Enterococcus spp. isolated from wild mammals in Aragón, Spain.

Yersiniosis is a zoonosis causing gastroenteritis, diarrhoea, and occasionally reactive arthritis and septicaemia. Cases are often linked to meat consumption and the most common aetiological agent is the Gram-negative bacilliform Yersinia enterocolitica bacterium. The occurrence of Yersinia spp. among wild animals has mostly been studied in wild boar, but it has seldom been in other species. A total of 1,868 faecal samples from animals found dead or hunted were collected between 2015 and 2018 in the Valle d’Aosta region of the northwestern Italian Alps. Alpine ibex faecal samples were collected during a health monitoring program in 2018. Bacteria were isolated via PCR and confirmed as Y. enterocolitica biochemically. Strain antimicrobial susceptibility was tested by Kirby–Bauer disc diffusion, and the presence of virulence factors and antimicrobial resistance genes was investigated using whole-genome sequencing. Yersinia enterocolitica strains of biotype 1A were detected in six faecal samples from red deer (0.93%), roe deer (0.49%) and red foxes (0.7%). Strains found in beech martens (3.57%) and Alpine ibex (2.77%) belonged to biotypes 1B and 5, respectively and harboured the pYPTS01 plasmid that had only been detected in Y. pseudotuberculosis PB1/+. All the isolates were resistant to ampicillin and erythromycin. The biovar 1A strains exhibited different virulence factors and behaved like non-pathogenic commensals. The strain from an Alpine ibex also harboured the self-transmissible pYE854 plasmid that can mobilise itself and the pYPTS01 plasmid to other strains. The beech marten could be considered a sentinel animal for Y. enterocolitica. Phenotypic resistance may account for the ability of all the strains to resist β-lactams.

Enterococci are widespread, being part of the bacterial flora of humans and animals. The food chain can be therefore considered as the main route of transmission of antibiotic resistant bacteria between the animal and human populations. Milk in particular represents a source from which resistant bacteria can enter the human food chain. The aim of the study was to determine the occurrence and resistance to antimicrobial agents of Enterococcus spp. strains isolated from raw goat’s milk samples. A total of 207 goat’s milk samples were collected. Samples were cultivated on selective media and confirmed as E. faecium or E. faecalis and screened for selected resistance genes by PCR. Drug susceptibility determination was performed by microdilution on Sensititre EU Surveillance Enterococcus EUVENC Antimicrobial Susceptibility Testing (AST) Plates and Sensititre US National Antimicrobial Resistance Monitoring System Gram Positive CMV3AGPF AST Plates. Enterococcal strains totalling 196 were isolated, of which 40.8% were E. faecalis and 15.3% were E. faecium. All tested isolates were susceptible to linezolid, penicillin and tigecycline. For most other antimicrobials the prevalence of resistance was 0.5–6.6% while high prevalence of quinupristin/dalfopristin (51.5%), tetracycline (30%) and lincomycin (52%) resistance was observed. This study affords better knowledge concerning the safety of raw goat’s milk in terms of the enterococci possible to isolate from this foodstuff. It seems that enterococci in milk are still mostly susceptible to antimicrobials of major concern as multiply resisted drugs, such as gentamycin and vancomycin. However, the presence of multi-resistant strains in goat milk is cause for apprehension.

Foot rot in small ruminants is highly contagious, causes severe lameness, and impairs fertility and wool and meat production. It is usually treated with parenteral antibiotics, with attendant antibiotic resistance risk, and with bactericidal footbaths, potentially harmful to humans and the environment. An alternative treatment in sheep is proposed based on repeated topical ozonated ointment application. Its effectiveness and safety were evaluated by estimation of acute-phase response, biochemical indicators of organic damage, and antioxidant/oxidant balance (AOB). The study was conducted on ten sheep with Egerton scale 2–3 lesions. Ozone application was repeated every day for seven days. Blood was drawn first (T0) after foot cleaning and before ozonation, then (T1) seven days after the first ozone application, and finally (T2) four days after the last application. High clinical effectiveness was observed, with total recovery by 28 days from the start of treatment. A significant increase in antiradical activity was noted on the basis of a 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assay from 1.16 ± 0.04 μmolTe/mL at T0 to 1.23 ± 0.03 μmolTe/mL at T1, with a slight decrease in oxidative stress. Calculated on the basis of antiradical capacity, AOB was higher at T1 (130 ± 19%) and decreased to 110 ± 16% at T2. Calculated on the basis of reducing power, it was 169 ± 22% at T1 and 131 ± 17% at T2. These results indicated that the AOB is efficient enough to prevent oxidative organ injury and the applied doses of ozone are safe for animals.

A significant threat to public health is presented by antibiotic-resistant strains of bacteria, selective pressure on which results from antibiotic use. Colistin is an antibiotic commonly used in veterinary medicine, but also one of last resort in human medicine. Since the 2015 discovery in China of the mcr-1 gene encoding colistin resistance in Enterobacteriaceae, other countries have noted its presence. This study was to find the mcr-1 gene prevalence in E. coli isolated from poultry slaughtered in Poland. Cloacal swabs were taken from December 2017 to October 2018 from broiler chickens in three regions. The samples (n = 158) were grouped as flocks treated with colistin sulphate (n = 87) and those not treated (n = 71). Resistance to antimicrobials commonly used in poultry was evaluated by minimum inhibitory concentration. The presence of the mcr-1 gene was confirmed by PCR. Isolates containing the mcr-1 gene were yielded by 11.27% of the samples from not treated flocks and 19.54% of those from treated flocks, but no statistically significant difference in the prevalence of the gene was seen between the groups. The results clearly preclude intensification of selective pressure for colistin resistance due to colistin sulphate treatment because they show that the avian gastrointestinal tract was already inhabited by colistin-resistant E. coli by the time the chickens came to the poultry house.

Integrons are mobile DNA elements that allow for acquisition and dissemination of antibiotic-resistance genes among pig farm-derived bacteria. Limited information is available on integrons of Staphylococcus aureus from pig farms. The aim of this study was to characterise and investigate the prevalence of class 1 and 2 integrons in multi-drug resistant (MDR) S. aureus isolates from pig farms. A total of 724 swabs were collected from 12 pig farms in Chongqing, China, and examined by conventional microbial and molecular methods. In total, 68 isolates were S. aureus, 57 of which were methicillin resistant (MRSA). All 68 isolates were MDR strains and carried integrons, of which 88.2% (60/68) harboured both class 1 and 2. In addition, 85.3% (58/68) of the class 2 integron-positive isolates carried the β-lactam resistance gene (blaTEM₋₁), and 66.7% (40/60) of the class 1 integron–positive isolates carried the aadA1c, aadA1 or dfrA1 gene for respective streptomycin and spectinomycin or trimethoprim resistance. Class 1 and 2 integrons are common among the pig farm-derived S. aureus isolates. On account of their significance for public health, the prevalence of the integrons and their associated resistance genes in pig farm-derived S. aureus isolates should be paid special attention.

Land application of manure that contains antibiotics and resistant bacteria may facilitate the establishment of an environmental reservoir of antibiotic-resistant microbes, promoting their dissemination into agricultural and natural habitats. The main objective of this study was to search for acquired antibiotic resistance determinants in the gut microbiota of wild boar populations living in natural habitats. Gastrointestinal samples of free-living wild boars were collected in the Zemplén Mountains in Hungary and were characterised by culture-based, metagenomic, and molecular microbiological methods. Bioinformatic analysis of the faecal microbiome of a hunted wild boar from Japan was used for comparative studies. Also, shotgun metagenomic sequencing data of two untreated sewage wastewater samples from North Pest (Hungary) from 2016 were analysed by bioinformatic methods. Minimum spanning tree diagrams for seven-gene MLST profiles of 104 E. coli strains isolated in Europe from wild boars and domestic pigs were generated in Enterobase. In the ileum of a diarrhoeic boar, a dominant E. coli O112ab:H2 strain with intermediate resistance to gentamicin, tobramycin, and amikacin was identified, displaying sequence type ST388 and harbouring the EAST1 toxin astA gene. Metagenomic analyses of the colon and rectum digesta revealed the presence of the tetQ, tetW, tetO, and mefA antibiotic resistance genes that were also detected in the gut microbiome of four other wild boars from the mountains. Furthermore, the tetQ and cfxA genes were identified in the faecal microbiome of a hunted wild boar from Japan. The gastrointestinal microbiota of the free-living wild boars examined in this study carried acquired antibiotic resistance determinants that are highly prevalent among domestic livestock populations.