Antimicrobial Resistance in Escherichia coli Strains Isolated from Humans and Pet Animals

Electrochemical and optical biosensors for the detection of E. Coli

E. coli is a common pathogenic microorganism responsible for numerous food and waterborne illnesses. Traditional detection methods often require long, multi-step processes and specialized equipment. Electrochemical and optical biosensors offer promising alternatives due to their high sensitivity, selectivity, and real-time monitoring capabilities. Recent advancements in sensor development focus on various techniques for detecting E. coli, including optical (fluorescence, colorimetric analysis, surface-enhanced Raman spectroscopy, surface plasmon resonance, localized surface plasmon resonance, chemiluminescence) and electrochemical (amperometric, voltammetry, impedance, potentiometric). Herein, the latest advancements in optical and electrochemical biosensors created for identifying E. coli with an emphasis on surface modifications employing nanomaterials and biomolecules are outlined in this review. Electrochemical biosensors exploit the unique electrochemical properties of E. coli or its specific biomolecules to generate a measurable signal. In contrast, optical biosensors rely on interactions between E. coli and optical elements to generate a detectable response. Moreover, optical detection has been exploited in portable devices such as smart phones and paper-based sensors. Different types of electrodes, nanoparticles, antibodies, aptamers, and fluorescence-based systems have been employed to enhance the sensitivity and specificity of these biosensors. Integrating nanotechnology and biorecognition (which bind to a specific region of the E. coli) elements has enabled the development of portable and miniaturized devices for on-site and point-of-care (POC) applications. These biosensors have demonstrated high sensitivity and offer low detection limits for E. coli detection. The convergence of electrochemical and optical technologies promises excellent opportunities to revolutionize E. coli detection, improving food safety and public health.

Predominance of enterotoxigenic Escherichia coli among ESBL/plasmid-mediated AmpC-producing strains isolated from diarrheic foals: a public health concern

BACKGROUND

The upsurge of diarrheagenic E. coli pathotypes carrying extended-spectrum beta-lactamases (ESBLs)/plasmid-mediated AmpC β-lactamase (pAmpC) among animals constitutes an emerging threat for humans and animals. This study investigated the burden of ESBL-/pAmpC-producing diarrheagenic E. coli among diarrheic foals and its potential public health implications. Rectal swabs were collected from 80 diarrheic foals. These swabs were processed to isolate and identify ESBL/pAmpC-producing E. coli using a selective culture medium, biochemical tests, phenotypic identification, and molecular identification of ESBL- and pAmpC-encoding genes. Moreover, all ESBL-/pAmpC-producing E. coli isolates were examined for different virulence genes related to diarrheagenic E. coli pathotypes.

RESULTS

Out of 80 examined foals, 26 (32.5%) were confirmed as ESBL-/pAmpC-producing E. coli, of which 14 (17.5%) animals carried only ESBL-producing E. coli, whereas 12 (15%) animals possessed ESBL-pAmpC-producing E. coli. The only detected diarrheagenic pathotype was enterotoxigenic, encoded by the heat-stable enterotoxin gene (ST) with a prevalence rate of 80.8% (21/26). The ST gene was further characterized where STa, STb, and STa + STb were found in one, four, and 16 strains, respectively. Moreover, all enterotoxigenic E. coli (ETEC) isolates exhibited a multidrug-resistance pattern. The phylogenetic analysis of 3 obtained partial STb sequences revealed high genetic relatedness to ETEC isolates retrieved from humans, conferring such sequences' public health significance.

CONCLUSIONS

These findings highlight that diarrheic foals could serve as a potential reservoir for multidrug-resistant ESBL-/pAmpC-producing enterotoxigenic E. coli.

Third-generation cephalosporin resistant Escherichia coli in dogs and cats in Germany in 2019-2021

OBJECTIVES

Antimicrobial resistance (AMR) poses a worldwide challenge, threatening global health. The objective of this research was to determine the 3rd generation cephalosporin resistance (3GCR) proportion in Escherichia (E.) coli isolated from clinical samples of dogs and cats in Germany.

METHODS

The study utilized result data from antimicrobial susceptibility testing (AST) of isolates obtained from diagnostic samples collected from dogs and cats send in for bacterial examination. Data includes AST results from 3,491 veterinary practices in Germany spanning the years 2019 to 2021, representing 33.1% of practices and clinics nationwide. Out of 175,171 clinical samples, a total of 25,491 E. coli strains (14,6%) were evaluated for their susceptibility to antimicrobials, in particular the 3rd generation cephalosporin cefovecin, but also aminoglycosides (gentamicin, GEN), fluoroquinolones (enrofloxacin, ENR), tetracyclines (doxycycline), phenicols (chloramphenicol), folate pathway inhibitors (sulfamethoxazole + trimethoprim), and nitrofurans (nitrofurantoin).

RESULTS

The cefovecin resistance proportion was 11.6% in the study period. Geographical analysis showed local variations in 3GCR in E. coli of ±3%. Regarding all E. coli isolates investigated, resistance proportions were observed as follows: 12% for sulfamethoxazole-trimethoprim, 7% for enrofloxacin, 8% for chloramphenicol and 4% for gentamicin. Notably, 3GCR E. coli showed significantly higher resistance proportions, specifically 30% for sulfamethoxazole-trimethoprim, 28% for chloramphenicol, 18% for enrofloxacin and 14% for gentamicin.

CONCLUSIONS

This study represents the first of its kind to utilize an extensive dataset encompassing dogs and cats across Germany. Companion animals have close contact to their owners and transmission of 3GCR between them is likely as well as acquisition from other environmental sources. Resistance proportions (6.7%) against the antibiotic ceftazidime as reported by the German AMR surveillance for human medicine were lower than in our veterinary data. Our study provides an overview of the current 3GCR resistance proportion in Germany and demonstrates the importance of integrated AMR monitoring.

Trends in the Prevalence of Antimicrobial Resistance in Escherichia coli Isolated from Outpatient Urine Cultures in French Amazonia

Antimicrobial resistance (AMR) in the community is increasing worldwide. We aimed to assess AMR trends in Escherichia coli from the community urine isolates in French Amazonia. We conducted a retrospective study from January 2016 to December 2022 in the Cayenne General Hospital microbiology laboratory (French Guiana). It included all urine samples positive for E. coli collected from adult outpatients. During the study period, 3,443 urinalyses positive for E. coli were studied. In 46% of cases, patients were women. In 64.4% of cases, E. coli were β-lactamase producers. The most frequently diagnosed resistance mechanisms were penicillinase production and sparing third-generation cephalosporins. Isolated E. coli were extended-spectrum β-lactamase (ESBL) producers in 6.1% of cases. Overall, E. coli was susceptible to amoxicillin in 35.9% [95% CI: 34.3-37.5], to amoxicillin/clavulanic acid in 62.2% [95% CI: 60.6-63.9], to cefotaxime in 94% [95% CI: 93.1-94.7], to gentamicin in 92.1% [95% CI: 89.1-92.6], to ofloxacin in 76.8% [95% CI: 75.3-78.2], to trimethoprim/sulfamethoxazole (SXT) in 58.8% [95% CI: 57.1-60.5], to fosfomycin in 99.1% [95% CI: 98.6-99.4], and to nitrofurantoin in 99% of cases [95% CI: 98.6-99.3]. We have observed a gradual decline in the susceptibility profile of E. coli for amoxicillin/clavulanic acid (P <0.001), piperacillin/tazobactam (P = 0.003), and temocillin (P = 0.006). However, susceptibility to ciprofloxacin was increasing (P = 0.001). In contrast, the susceptibility trends for amoxicillin, third-generation cephalosporins, gentamicin, SXT, nitrofurantoin, and fosfomycin remained stable over the 28 quarters of the study. In conclusion, isolated E. coli from outpatient urinalyses showed increased resistance profiles involving penicillinase and ESBL production. Close monitoring and strategies to decrease antibiotic consumption in the community are needed.

Population structure and antibiotic resistance of swine extraintestinal pathogenic Escherichia coli from China

Extraintestinal Pathogenic Escherichia coli (ExPEC) pose a significant threat to human and animal health. However, the diversity and antibiotic resistance of animal ExPEC, and their connection to human infections, remain largely unexplored. The study performs large-scale genome sequencing and antibiotic resistance testing of 499 swine-derived ExPEC isolates from China. Results show swine ExPEC are phylogenetically diverse, with over 80% belonging to phylogroups B1 and A. Importantly, 15 swine ExPEC isolates exhibit genetic relatedness to human-origin E. coli strains. Additionally, 49 strains harbor toxins typical of enteric E. coli pathotypes, implying hybrid pathotypes. Notably, 97% of the total strains are multidrug resistant, including resistance to critical human drugs like third- and fourth-generation cephalosporins. Correspondingly, genomic analysis unveils prevalent antibiotic resistance genes (ARGs), often associated with co-transfer mechanisms. Furthermore, analysis of 20 complete genomes illuminates the transmission pathways of ARGs within swine ExPEC and to human pathogens. For example, the transmission of plasmids co-harboring fosA3, blaCTX-M-14, and mcr-1 genes between swine ExPEC and human-origin Salmonella enterica is observed. These findings underscore the importance of monitoring and controlling ExPEC infections in animals, as they can serve as a reservoir of ARGs with the potential to affect human health or even be the origin of pathogens infecting humans.

The Antimicrobial Effect of Cornus mas L. and Sorbus aucuparia L. Fruit Extracts against Resistant Uropathogens in Correlation with the Prevalence of Urinary Tract Infections in Companion Animals

Urinary tract infections (UTIs) are a widespread condition in pets, with many antibiotics being prescribed, contributing to the rise in antimicrobial resistance, which is a worldwide threat. This study's main objective was to analyze the in vitro antimicrobial activity of Cornus mas and Sorbus aucuparia fruit hydro-ethanolic extracts towards bacteria identified in the urine of companion animals experiencing UTIs. Urine samples were collected from dogs and cats (n = 83; 47 negative, 36 positive); several bacterial strains were identified (n = 49) belonging to the Escherichia, Enterococcus, Staphylococcus, Proteus, Klebsiella, Enterobacter, Pseudomonas, Acinetobacter, Leclercia, and Kocuria genera. Bacterial susceptibility was tested using the disk diffusion method, with the majority being resistant to several beta-lactams, quinolones, trimethoprim/sulfamethoxazole, and nitrofurantoin. Subsequently, 13 resistant isolates were selected to evaluate the fruits extracts' antimicrobial potential using the agar well diffusion and broth microdilution methods. Cornus mas exhibited the greatest activity against Gram-negatives (primarily Pseudomonas luteola), while Sorbus aucuparia showed maximum effects towards Gram-positives (particularly Enterococcus faecalis). The MIC was 0.01 μg/μL for both extracts; the MBC was 0.08 μg/μL for Cornus mas and 0.05 μg/μL for Sorbus aucuparia. However, Cornus mas showed a stronger bactericidal effect. This is the first study to investigate these fruit extracts in UTI isolates of companion animals, and these extracts might be used as substitutes or adjuvants for antibiotics, thus contributing to a reduction in antimicrobial resistance.

Phenotypic and Genotypic Characterizations of Antimicrobial-Resistant Escherichia coli Isolates from Diverse Retail Meat Samples in North Carolina During 2018-2019

Surveillance of antimicrobial-resistant pathogens in U.S. retail meats is conducted to identify potential risks of foodborne illness. In this study, we conducted a phenotypic and genotypic analysis of Escherichia coli recovered from a diverse range of retail meat types during 2018-2019 in North Carolina. The investigation was conducted as part of the National Antimicrobial Resistance Monitoring System (NARMS). Retail meat sampling and E. coli isolation were performed in accordance with NARMS retail meat isolation protocols. We used the Sensititre™ broth microdilution system to determine phenotypic resistance to 14 antimicrobial agents and the Illumina next-generation sequencing platform for genotypic resistance profiling. The highest prevalence of E. coli isolates was found in ground turkey (n = 57, 42.9%) and chicken (n = 27, 20.3%), followed by ground beef (n = 25, 18.9%) and pork (n = 24, 18%). The isolates were divided into seven different phylogroups using the Clermont typing tool, with B1 (n = 59, 44.4%) and A (n = 39, 29.3%) being the most dominant, followed by B2 (n = 14, 10.5%), D (n = 7, 5.3%), F (n = 6, 4.5%), E (n = 3, 2.3%), and C (n = 2, 1.5%). Using multilocus sequence typing (MLST), 128 Sequence types (STs) were identified indicating high diversity. Phenotypic and genotypic resistance was observed toward aminoglycosides, sulfonamides, beta-lactams, macrolides, tetracyclines, phenicols, and fluoroquinolones. Ground turkey samples were more resistant to the panel of tested antimicrobials than chicken, beef, or pork (p < 0.05). All isolates were found to be susceptible to meropenem. A high percentage of turkey isolates (n = 16, 28%) were multidrug-resistant (MDR) compared with 18.5% of chicken (n = 5), 8.4% of pork (n = 2), and 8% of beef isolates (n = 2). This study highlights the benefit of surveillance to identify MDR E. coli for epidemiologic tracking and is a comprehensive report of the phenotypic and genotypic characterization of E. coli isolated from retail meats in North Carolina.

Isolation and characterization of lytic bacteriophages from various sources in Addis Ababa against antimicrobial-resistant diarrheagenic Escherichia coli strains and evaluation of their therapeutic potential

BACKGROUND

Escherichia coli is a common fecal coliform, facultative aerobic, gram-negative bacterium. Pathogenic strains of such microbes have evolved to cause diarrhea, urinary tract infections, and septicemias. The emergence of antibiotic resistance urged the identification of an alternative strategy. The use of lytic bacteriophages against the control of pathogenic E. coli in clinics and different environmental setups (waste and drink water management) has become an alternative therapy to antibiotic therapy. Thus, this study aimed to isolate and characterize lytic bacteriophage from various sources in Addis Ababa, tested them against antimicrobial-resistant diarrheagenic E. coli strains and evaluated their therapeutic potential under in vitro conditions.

METHODS

A total of 14 samples were processed against six different diarrheagenic E. coli strains. The conventional culture and plaque analysis agar overlay method was used to recover lytic bacteriophage isolates. The phage isolates were characterized to determine their lytic effect, growth characteristics, host range activity, and stability under different temperature and pH conditions. Phage isolates were identified by scanning electron microscope (SEM), and molecular techniques (PCR).

RESULTS

In total, 17 phages were recovered from 84 tested plates. Of the 17 phage isolates, 11 (65%) were Myoviridae-like phages, and 6 (35%) phage isolates were Podoviridae and Siphoviridae by morphology and PCR identification. Based on the host range test, growth characteristics, and stability test 7 potent phages were selected. These phages demonstrated better growth characteristics, including short latent periods, highest burst sizes, and wider host ranges, as well as thermal stability and the ability to survive in a wide range of pH levels.

CONCLUSIONS

The promising effect of the phages isolated in this study against AMR pathogenic E. coli has raised the possibility of their use in the future treatment of E. coli infections.

Exploring the potential of radiolabeled duramycin as an infection imaging probe

The continuous pursuit of designing an ideal infection imaging agent is a crucial and ongoing endeavor in the field of biomedical research. Duramycin, an antimicrobial peptide exerts its antimicrobial action on bacteria by specific recognition of phosphatidylethanolamine (PE) moiety present on most bacterial membranes, particularly Escherichia coli (E. coli). E. coli membranes contain more than 60% PE. Therefore, duramycin is an attractive candidate for the formulation of probes for in situ visualization of E. coli driven focal infections. The aim of the present study is to develop 99m Tc labeled duramycin as a single-photon emission computed tomography (SPECT)-based agent to image such infections. Duramycin was successfully conjugated with a bifunctional chelator, hydrazinonicotinamide (HYNIC). PE specificity of HYNIC-duramycin was confirmed by a dye release assay on PE-containing model membranes. Radiolabeling of HYNIC-duramycin with 99m Tc was performed with consistently high radiochemical yield (>90%) and radiochemical purity (>90%). [99m Tc]Tc-HYNIC-duramycin retained its specificity for E. coli, in vitro. SPECT and biodistribution studies showed that the tracer could specifically identify E. coli driven infection at 3 h post injection. While 99m Tc-labeled duramycin is employed for monitoring early response to cancer therapy and cardiotoxicity, the current studies have confirmed, for the first time, the potential of utilizing 99m Tc labeled duramycin as an imaging agent for detecting bacteria. Its application in imaging PE-positive bacteria represents a novel and promising advancement.

Antimicrobial Resistance in Escherichia coli Isolated from Healthy Dogs and Cats in South Korea, 2020-2022

The occurrence of antimicrobial-resistant bacteria in companion animals poses public health hazards globally. This study aimed to evaluate the antimicrobial resistance profiles and patterns of commensal E. coli strains obtained from fecal samples of healthy dogs and cats in South Korea between 2020 and 2022. In total, 843 E. coli isolates (dogs, n = 637, and cats, n = 206) were assessed for susceptibility to 20 antimicrobials. The resistance rates of the most tested antimicrobials were significantly higher in dog than in cat isolates. Cefalexin (68.9%) demonstrated the highest resistance rates, followed by ampicillin (38.3%), tetracycline (23.1%), and cefazolin (18.7%). However, no or very low resistance (0-0.6%) to amikacin, imipenem, piperacillin, and colistin was found in both dog and cat isolates. Overall, 42.3% of the isolates exhibited multidrug resistance (MDR). MDR in isolates from dogs (34.9%) was significantly higher than in those from cats (20.9%). The main components of the resistance patterns were cefalexin and ampicillin in both dog and cat isolates. Additionally, MDR patterns in isolates from dogs (29.2%) and cats (16%) were shown to encompass five or more antimicrobials. Multidrug-resistant commensal E. coli could potentially be spread to humans or other animals through clonal or zoonotic transmission. Therefore, the incidence of antimicrobial resistance in companion animals highlights the urgent need to restrict antimicrobial resistance and ensure the prudent use of antimicrobials in Korea.

Antimicrobial resistance in E. Coli of animal origin and discovery of a novel ICE mobile element in Northeast China

BACKGROUND

Multidrug resistance in Enterobacteriaceae including resistance to quinolones is rising worldwide. The development of resistance may lead to the emergence of new transmission mechanisms. In this study, the collection of different E. coli was performed from animals and subjected to subsequent procedures including pulsed-field gel electrophoresis, micro-broth dilution method, polymerase chain reaction. Whole genome sequencing of E. coli C3 was performed to detect the affinity, antimicrobial resistance and major carriers of the isolates.

RESULTS

A total of 66 E. coli were isolated and their antibiotic resistance genes, frequency of horizontal transfer and genetic environment of E. coli C3 were determined. The results showed there were both different and same types in PFGE typing, indicating clonal transmission of E. coli among different animals. The detection of antimicrobial resistance and major antibiotic resistance genes and the plasmid transfer results showed that strains from different sources had high levels of resistance to commonly used clinical antibiotics and could be spread horizontally. Whole-genome sequencing discovered a novel ICE mobile element.

CONCLUSION

In summary, the antimicrobial resistance of E. coli in northeast China is a serious issue and there is a risk of antimicrobial resistance transmission. Meanwhile, a novel ICE mobile element appeared in the process of antimicrobial resistance formation.

Prevalence and characterization of antimicrobial-resistant Escherichia coli isolated from veterinary staff, pets, and pet owners in Thailand

BACKGROUND

Companion animals may act as antimicrobial resistance (AMR) reservoirs. This study investigated the prevalence and AMR patterns of Escherichia coli in pets and people in close contact with pets.

METHODS

A total of 955 samples were collected from veterinary clinics across Thailand by rectal and skin or ear swabs from dogs and cats and fecal swabs from veterinarians, veterinary assistants, and pet owners. The minimum inhibitory concentrations (MICs) of the obtained isolates were investigated using Sensititre™ MIC plates against 21 different antimicrobial drugs.

RESULTS

Escherichia coli from pets was frequently resistant to ampicillin (100%) and amoxicillin-clavulanic acid (100%), whereas E. coli from pet owners, veterinarians, and veterinary assistants was mostly resistant to tetracycline. The multiple antibiotic resistance index revealed that multidrug-resistant E. coli isolates were frequently found in dogs (34.92%), cats (62.12%), veterinarians (61.11%), veterinarian assistants (36.36%), and pet owners (47.62%). The most common AMR genes identified in this study were blaCTX-M, blaTEM, tetA, and tetB, which were associated with the antimicrobial susceptibility results. Additionally, extended-spectrum beta-lactamase (ESBL)-associated genes (i.e., blaCTX-M, blaTEM, and blaSHV) were found in 21.69%, 71.97%, 27.78%, and 21.43% of E. coli isolated from dogs, cats, veterinarians, and pet owners, respectively.

CONCLUSIONS

Our findings demonstrated the presence of AMR genes, particularly ESBL-associated genes, in E. coli isolated from healthy pets and veterinarians. This implies that these sources of E. coli could potentially be reservoirs for antibiotic resistance, thereby increasing the risk of harm to both humans and animals. These findings highlight the importance of implementing effective AMR control measures in veterinary practices, as bacteria resistant to commonly used antimicrobials are present in humans and animals.

Antibacterial activity of thymoquinone derivative

Natural products such as terpenoidal compounds have been extremely tested against pathogenic bacteria. Researches are frequently carried out to find out new natural, semisynthetic and synthetic antibacterial agents due to problems of resistance. Thymoquinone derivative was obtained in our previous study and the current research is a continuation. The antibacterial activity of a monoterpenoid; thymoquinone derivative, 5-isopropyl-2-methyloxepine-1-one (1) has been evaluated for the first time by following the Agar cup bioassay method employed. The bacterial strains used in this study were Escherichia coli and Bacillus subtilis. Compound 1 showed moderate activity against Gram-positive organism; B. subtilis and good activity against Gram-negative species; E. coli with zones of inhibition (ZOI) 10.0 ± 0.2 mm and 11.0 ± 0.2 mm against E. coli and B. subtilis, respectively, and in comparison with antibiotic, imipenem. The zones of inhibition were calculated as the mean of the triplicate. The antibacterial activity of thymoquinone derivative 1 could be explained by the presence of unsaturated lactone.

Profiling of Antimicrobial Resistance Genes and Integron from Escherichia coli Isolates Using Whole Genome Sequencing

This study is designed to investigate Escherichia coli for the antibiotic resistance genes (ARGs) and integrons from healthy as well as diarrhoeic/diseased animals/birds' faecal samples. A total of eight samples were selected for the study; from each animal, two samples were taken, one from healthy animals/birds and one from diarrhoeic/diseased animals/birds. Antibiotic sensitivity testing (AST) and whole genome sequencing (WGS) was performed for selected isolates. The E. coli isolates showed resistance to moxifloxacin, followed by erythromycin, ciprofloxacin, pefloxacin, tetracycline, levofloxacin, ampicillin, amoxicillin, and sulfadiazine (4/8, 50.00% each). The E. coli isolates were 100% sensitive to amikacin, followed by chloramphenicol, cefixime, cefoperazone, and cephalothin. A total of 47 ARGs from 12 different antibiotic classes were detected among the eight isolates by WGS. The different classes of antibiotics included aminoglycoside, sulphonamide, tetracycline, trimethoprim, quinolone, fosfomycin, phenicol, macrolide, colistin, fosmidomycin, and multidrug efflux. The class 1 integrons were detected in 6/8 (75.00%) isolates with 14 different gene cassettes.

Antimicrobial resistance profiles of Escherichia coli isolated from laying hens in Zambia: implications and significance on one health

Background

Antimicrobial resistance (AMR) has been deepening in the layer poultry sector in Zambia partly due to the inappropriate use of antimicrobials. Escherichia coli (E. coli), a commensal and zoonotic bacterium, can potentially be a source of AMR.

Objectives

This study assessed the phenotypic AMR profiles of E. coli isolated from the apparent health-laying hens in Lusaka and Copperbelt provinces of Zambia.

Methods

A cross-sectional study was conducted between September 2020 and April 2021 in which 365 cloacal swabs were collected from 77-layer farms based in Lusaka and Copperbelt provinces of Zambia. E. coli isolation and identification were done using cultural and biochemical properties and confirmed using the 16S rRNA gene sequencing. Antimicrobial susceptibility testing (AST) was done using the Kirby-Bauer disc-diffusion method. Data analysis was done using WHONET 2020 and Stata v.16.1.

Results

Of the 365 samples, E. coli was isolated from 92.9% (n = 339). The AMR was detected in 96.5% (n = 327) of the isolates, of which 64.6% (n = 219) were multidrug-resistant (MDR). E. coli was highly resistant to tetracycline (54.6%) and ampicillin (54%) but showed low resistance to meropenem (0.9%), ceftazidime (6.2%) and chloramphenicol (8.8%).

Conclusion

This study found a high prevalence of E. coli resistant to some commonly used antibiotics in poultry, which is a public health concern because of the potential contamination of eggs and layers of chicken meat that enter the food chain. Urgent attention is needed, including strengthening antimicrobial stewardship and surveillance programmes in layer poultry production in Zambia.

Antibiotic governance and use on commercial and smallholder farms in eastern China

Introduction

China is one of the largest consumers of agricultural antibiotics in the world. While the Chinese government has been tightening its regulations to control antimicrobial resistance (AMR) from animal sources in recent years, the extent of antimicrobial oversight and the practices of antibiotic use in animal agriculture in China has not yet been explored. This study describes the practices of antimicrobial management in eastern China and current scenarios of antibiotic use in commercial farms and smallholder backyard farming.

Methods

33 semi-structured interviews were conducted with government agriculture officials, veterinary drug sellers, farmers and smallholders in two contrasting areas of rural Zhejiang and Jiangsu provinces, China. Interview transcripts were analyzed in NVivo12 using a thematic approach.

Results

Findings revealed that although the governance of antibiotic use has made progress, especially in controlling irrational antibiotic use in commercial farms, smallholders are under-regulated due to a lack of resources and assumptions about their marginal role as food safety governance targets. We also found that smallholders resort to human antibiotics for the treatment of backyard animals because of economic constraints and lack of access to professional veterinary services.

Discussion

More attention needs to be devoted to the local structural needs of farmers to reduce antibiotic misuse. Considering the extensive links of AMR exposure under the One Health framework, efforts to integrate smallholders in antibiotic governance are required to address the AMR burden systematically in China.

Microbial Resistance to Antibiotics and Biofilm Formation of Bacterial Isolates from Different Carp Species and Risk Assessment for Public Health

The aim of this research was to investigate the effects of biofilm on antibiotic resistance of the bacterial isolates present in fish meat and to assess the risk of antibiotic residues for public health. Common carp, silver carp and grass carp fishes were purchased from retail stores for an in vitro biofilm investigation and a drug-resistant pattern determination. In all samples, up to 10⁴ CFU/g of bacteria, such as Escherichia coli, Aeromonas hydrophila, Shewanella putrefaciens, Vibrio spp. and Staphylococcus spp., were observed. Isolates from the samples and their biofilms were subjected to an antibiogram assay using antibiotics such as amoxicillin, ampicillin, cefotaxime, ciprofloxacin, chloramphenicol, gentamicin, streptomycin, tetracycline and trimethoprim. Obtained results showed that some of the isolates were sensitive to antibiotics and some were resistant. Results of LC-MS/MS analysis showed that antibiotics residues were present in fish samples in the range between 4.9 and 199.4 µg/kg, with a total sum of 417.1 µg/kg. Estimated daily intake (EDI) was established to be 0.274 μg/kg of body weight/day for men and 0.332 μg/kg of body weight/day for women, with an acceptable daily intake (ADI) of 8.5 and 7.0 µg/kg of body weight/day for men and women, respectively. The results of the present study, therefore, highlight the safe consumption of fresh fish.

Porphyrin Polymers Bearing N,N'-Ethylene Crosslinkers as Photosensitizers against Bacteria

The appearance of microbes resistant to antibiotics requires the development of alternative therapies for the treatment of infectious diseases. In this work two polymers, PTPPF₁₆-EDA and PZnTPPF₁₆-EDA, were synthesized by the nucleophilic aromatic substitution of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin and its Zn(II) complex with ethylenediamine, respectively. In these structures, the tetrapyrrolic macrocycles were N,N'-ethylene crosslinked, which gives them greater mobility. The absorption spectra of the polymers showed a bathochromic shift of the Soret band of ~10 nm with respect to the monomers. This effect was also found in the red fluorescence emission peaks. Furthermore, both polymeric materials produced singlet molecular oxygen with high quantum yields. In addition, they were capable of generating superoxide anion radicals. Photodynamic inactivation sensitized by these polymers was tested in Staphylococcus aureus and Escherichia coli bacteria. A decrease in cell viability greater than 7 log (99.9999%) was observed in S. aureus incubated with 0.5 μM photosensitizer upon 30 min of irradiation. Under these conditions, a low inactivation of E. coli (0.5 log) was found. However, when the cells were treated with KI, the elimination of the Gram-negative bacteria was achieved. Therefore, these polymeric structures are interesting antimicrobial photosensitizing materials for the inactivation of pathogens.

Extent and Resistance Patterns of ESKAPE Pathogens Isolated in Pus Swabs from Hospitalized Patients

Antimicrobial resistance has persisted as a global threat with increasing associated numbers of morbidity and mortality. ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) were termed by the Infectious Diseases Society of America as a group of bacteria with rapid antibiotic resistance development. The aim of the study was to describe the extent and resistance patterns of ESKAPE pathogens isolated in pus swabs from patients admitted at Muhimbili National Hospital, Tanzania. A retrospective cross-sectional study was performed in August 2019. A total of 75 admitted patients with open wounds and surgical site infections were recruited. Files were analyzed to collect microbiology laboratory data and relevant patient data. A total of 76 clinically significant bacteria were isolated of which 52 bacteria were categorized as ESKAPE pathogens. The most common bacteria isolated were 25% (n = 19/76) P. aeruginosa and 17.1% S. aureus. A high level of antibiotic resistance was shown in all ESKAPE and non-ESKAPE pathogens. The Gram-negative bacteria of ESKAPE pathogens were further analyzed comparing 3^rd generation cephalosporin and carbapenems resistance patterns. A. baumannii showed the highest resistance towards 3^rd generation cephalosporin and carbapenems. In addition, P. aeruginosa showed high resistance to 3^rd generation cephalosporins with 89.5% resistance, with E. coli showing high resistance to carbapenems with 50.0% resistance. The burden of ESKAPE pathogens is high in pus swabs obtained from admitted patients at Muhimbili National Hospital. The results showed high antibiotic resistance within ESKAPE and non-ESKAPE pathogens including the "last resort" antibiotics: 3^rd generation cephalosporin and carbapenems.

Relationship between Biofilm Formation and Antibiotic Resistance and Adherence Genes in Staphylococcus aureus Strains Isolated from Raw Cow Milk in Shahrekord, Iran

The production of biofilms by S. aureus contributes significantly to treatment failures. The present study aims to establish the relationship between biofilm formation and antibiotic resistance and adhesion genes in Staphylococcus aureus strains isolated from raw cow milk in Shahrekord, Iran. A total of 90 samples of raw cow's milk were collected. Presumptive S. aureus strains were obtained using Baird-Parker plates after enrichment in tryptone soy broth, and final colonies were selected from brain heart infusion. Additional tests such as coagulase were done, and the identification was confirmed by the detection of the aroA gene. Biofilm producing strains were screened using a spectrophotometry method applied to microplates. Crystal violet staining was used to quantify the formation of biofilm. An antibiotic susceptibility test was performed using the Kirby-Bauer disc diffusion method. PCR was used to detect several biofilm and antibiotics resistance related genes. The chi-square test and Fisher's exact test were used to establish a statistically significant relationship between biofilm reaction and antibiotic resistance (p value <0.05). Results show a moderate (38.88%) recovery rate of S. aureus in milk and 65.71% of the isolates were strong biofilm producers. Antibiotic susceptibility tests show an alarming rate of resistance to beta-lactam antibiotics, especially penicillin (100%), ampicillin (91.42%), and oxacillin (71.42%). This finding correlates with antibiotic resistance gene detection, in which the gene blaZ was most found (71.42%), followed by mecA and Aac-D (42.85%). Detection of biofilm-related genes shows that all the genes targeted were found among S. aureus isolates. Statistical tests show a significant correlation between biofilm production and antibiotic resistance in S. aureus. This study revealed that there is a significant correlation between biofilm production and antibiotic resistance in S. aureus isolated from raw milk. These results highlight the need for regular surveillance of the occurrence of S. aureus strains in milk and milk products in Iran.

Attitude, Opinions, and Working Preferences Survey among Pet Practitioners Relating to Antimicrobials in India

The indiscriminate usage and overuse of antimicrobials in pets or companion animals are underlying causes of antimicrobial resistance (AMR). Despite the multi-faceted global challenge presented by antimicrobial resistance, very few studies have appraised pet practitioners’ factors, such as written policy on antimicrobials, dose rate prescribed, use of critically important antimicrobials, and antimicrobial prescription in clean surgical procedures, which can contribute to AMR. In the present study, an online cross-sectional survey among randomly selected pet practitioners (n = 104) of various Indian provinces and union territories was conducted using a questionnaire comprising 33 closed-ended questions on different parameters, viz., the dosage regimen and level of compliance towards guidelines of the World Health Organization (WHO), other relevant veterinary associations, and their opinion while prescribing antimicrobials. Almost every practitioner of the 104 respondents had revealed the difficulties with owner compliance; i.e., incomplete course of the antibiotics, inappropriate follow-ups, and improper care of the sick animals. The majority of practitioners (95%) reported self-prescription of antimicrobials by the owner before presenting the pet(s) to the veterinary clinic, whereas more than half of the respondents (64%) revealed unavailability of antibiogram facilities. Furthermore, a large number (76%) of practitioners stated empirical treatment based on their experience as the main criteria for antimicrobial choice in the absence of timely results from the laboratory. Although non-necessitated use of antimicrobials in clean surgical procedures has been claimed, surprisingly, the majority of pet practitioners (97%) reported their use to reduce the post-operative complications. The use of the highest priority, critically important antimicrobials (HPCIA) listed by the WHO for humans, particularly quinolones and third-generation cephalosporin, also has been reported for different infections. The treatment durations were nearly as per the recommended guidelines issued by the Danish Small Animal Veterinary Association (DSAVA) for different ailments. Analysis using chi-square tests exhibited a significant correlation between less experienced veterinarians (less than 5 years) and prescription of antimicrobials restricted for critically important infections in human medicine. However, there seems to be no association between the experience of the practitioner and the further studied parameters, namely, antimicrobial regimen prescription, weighing the animals before prescription, dose rate calculation, and antimicrobial selection and use after clean surgical operations. The findings suggest periodic awareness campaigns among practitioners regarding the implementation of the official guidelines, the need for systematic surveillance of AMR, awareness among pet owners about antimicrobial resistance, and the importance of rational use of antimicrobials on their pets.

Multi-Drug Resistant Pathogenic Escherichia coli Isolated from Wild Birds, Chicken, and the Environment in Malaysia

Transmission of pathogenic microorganisms in the last decades has been considered a significant health hazard and pathogenic E. coli, particularly antibiotic-resistant strains, have long been identified as a zoonotic problem. This study aimed to investigate multidrug resistant pathogenic E. coli isolates from wild birds, chickens, and environment in selected Orang Asli and Malay villages in Peninsular Malaysia. The bacteriological culture-based technique, disc diffusion method, and multiplex Polymerase Chain Reaction (mPCR) assay was used to determine the occurrence of pathogenic E. coli strains in the several samples in the study. E. coli isolates showed a variety of multi-drug resistant (MDR) antibiotypes and Enteropathogenic E. coli (EPEC) and Enteroinvasive E. coli (EIEC) were the most predominantly identified pathogenic E. coli strains. The findings of this study demonstrated the significance of animal reservoirs and the environment as sources of pathogenic E. coli, resistant bacteria, and resistance genes. Hence, there is a need for adoption of a practical surveillance approach on MDR pathogens to control foodborne contamination.

Antimicrobial resistance: new insights and therapeutic implications

Antimicrobial resistance has not been a new phenomenon. Still, the number of resistant organisms, the geographic areas affected by emerging drug resistance, and the magnitude of resistance in a single organism are enormous and mounting. Disease and disease-causing agents formerly thought to be contained by antibiotics are now returning in new forms resistant to existing therapies. Antimicrobial resistance is one of the most severe and complicated health issues globally, driven by interrelated dynamics in humans, animals, and environmental health sectors. Coupled with various epidemiological factors and a limited pipeline for new antimicrobials, all these misappropriations allow the transmission of drug-resistant organisms. The problem is likely to worsen soon. Antimicrobial resistance in general and antibiotic resistance in particular is a shared global problem. Actions taken by any single country can adversely or positively affect the other country. Targeted coordination and prevention strategies are critical in stopping the spread of antibiotic-resistant organisms and hence its overall management. This article has provided in-depth knowledge about various methods that can help mitigate the emergence and spread of antimicrobial resistance globally. KEY POINTS: • Overview of antimicrobial resistance as a global challenge and explain various reasons for its rapid progression. • Brief about the intrinsic and acquired resistance to antimicrobials and development of antibiotic resistance in bacteria. • Systematically organized information is provided on different strategies for tackling antimicrobial resistance for the welfare of human health.

Antimicrobial Resistance in E. coli Isolated from Chicken Cecum Samples and Factors Contributing to Antimicrobial Resistance in Nepal

Microorganisms with antimicrobial resistance (AMR) are prevalent among humans and animals, and also found in the environment. Though organisms with AMR can spread to humans via food from animal sources, the burden of AMR in food-producing animals remains largely unknown. Thus, we assessed the resistance pattern among Escherichia coli isolated from chicken cecum samples and explored issues contributing to AMR in animals in the Dhulikhel Municipality of Nepal. We conducted a mixed-methods study, comprising a cross-sectional quantitative component, with collection of chicken cecal samples from slaughter houses/shops. In addition, a descriptive qualitative component was undertaken, with a focus group discussion and key informant interviews among stakeholders involved in animal husbandry. Of the 190 chicken cecum samples collected, 170 (89%) were subjected to culture and drug sensitivity testing, of which E. coli was isolated from 159 (94%) samples. Of the 159 isolates, 113 (71%) had resistance to ≥3 antimicrobial class. Resistance to tetracycline (86%) and ciprofloxacin (66%) were most prevalent. Overuse of antimicrobials, easy availability of antimicrobials, and lack of awareness among farmers about AMR were major issues contributing to AMR. The high prevalence of resistance among E. coli in chicken cecal samples calls for rational use of antimicrobials, educating farmers, and multi-sectoral coordination.

Adsorption-desorption and degradation of colistin in soils under aerobic conditions

Colistin has broad-spectrum activity against Gram-negative bacteria and has been considered as the last-resort treatment for multiantibiotic-resistant Gram-negative bacteria infections in human. And it is also world widely utilized as a veterinary medicine for the promotion of growth, prevention and control of diseases in livestock and poultry. Extensive use of colistin in husbandry results in the introduction of large amounts of colistin to the surrounding environment via animals' urine and feces, potentially inducing the prevalence of colistin resistance bacteria and the impact of the ecological environment. The study investigated the adsorption, desorption and degradation of colistin in soils using high sensitivity UPLC-MS/MS assays. An MS based assay was established to directly determine colistin in the soil. It was observed that the moderate adsorption affinity of colistin to the three soils with adsorption strength (1/n) ranging from 0.6897 to 1.3333. Colistin exhibited the highest adsorption affinity to the sandy loam, followed by the sand and loam. Despite of different characteristics of three soils, the adsorption capacity of the three soils was comparable. The adsorption of colistin to the three types of soils analyzed was irreversible. The degradation experiments showed that the degradation of colistin in the sandy loam was relatively slow with a degradation half-life in a range of 13.2-29.7 days when colistin was applied to the sandy loam at a level of 10 ~ 40 µg/g. The degradation of colistin occurred in the mixture of the sandy loam and feces recovered from the colistin treated broiler as well. 25% of colistin remained in the mixture under environmental conditions after 14 days. Composting the sandy loam by directly covering the soil surface with colistin treated broilers' feces resulted in the introduction of colistin to the sandy loam. Colistin was observed in both the topsoil from the contact surface and sandy loam samples collected 20 cm below the contact surface. The understanding of adsorption-desorption behaviors, degradation and mobility of colistin in soils might offer insights into the potential impact of colistin on the emergence and prevalence of resistant bacteria and the ecological environment.

Optimization of Veterinary Antimicrobial Treatment in Companion and Food Animals

Several international strategies for antimicrobial stewardship have been developed in response to the global crisis of antimicrobial resistance [...].

The Resistance Patterns in E. coli Isolates among Apparently Healthy Adults and Local Drivers of Antimicrobial Resistance: A Mixed-Methods Study in a Suburban Area of Nepal

Evidence-based decision-making to combat antimicrobial resistance (AMR) mandates a well-built community-based surveillance system for assessing resistance patterns among commensals and pathogenic organisms. As there is no such surveillance system in Nepal, we attempted to describe the antimicrobial resistance pattern in E. coli isolated from the fecal samples of apparently healthy individuals in Dhulikhel municipality and also explored the local drivers of AMR. We used a mixed-method design with a cross-sectional quantitative component and a descriptive qualitative component, with focus group discussion and key informant interviews as the data collection method. Fecal samples were collected from 424 individuals randomly selected for the study. E. coli was isolated from 85.9% of human fecal samples, of which 14% were resistant to ≥3 class of antimicrobials (multidrug resistant). Of the 368 isolates, resistance to ampicillin (40.0%), tetracycline (20.7%) and cefotaxime (15.5%) were most prevalent. The major drivers of AMR were: lack of awareness of AMR, weak regulations on sales of antimicrobials, poor adherence to prescribed medications, and incomplete dosage due to financial constraints. These findings indicate the need for strict implementation of a national drug act to limit the over-the-counter sales of antimicrobials. Additionally, awareness campaigns with a multimedia mix are essential for educating people on AMR.

Effect of Raw Chickpea in the Broiler Chicken Diet on Intestinal Histomorphology and Intestinal Microbial Populations

The aim of the study was to determine the effect of partial replacement of SBM protein with CPR-derived protein in the broiler rearing period from 22 to 42 days of age on the intestinal histomorphology and the composition of the intestinal microbial population. Male broiler chicks aged 1 day were assigned to two groups with different nutrition schemes (n = 100 in each, 5 cages of 20 chicks in each). The chickens were reared for 42 days. All birds were fed isonitrogenous and isoenergetic diets: starter (1 to 21 d), grower (22 to 35 d), and finisher (36 to 42 d). From rearing day 22, different diets were provided to the birds: the SBM group received feed with 100% soybean meal protein, and the diet of the CPR group the protein originated from soybean meal was replaced by 50% chickpea protein. The study results indicated a significant impact of the inclusion of CPR in the diet on the basic intestinal structures (thickness of myenteron: submucosa, jejunum and duodenum mucosa, and jejunum transversal lamina). The addition of CPR led to shortening of intestinal villi, an increase in villus thickness, and reduced intestine absorptive surface in the duodenum and jejunum. The CPR group exhibited a significantly lower villus length-to-crypt depth ratio in the jejunum (p < 0.001). The inclusion of chickpeas in the diet increased the total count of mesophilic bacteria and coliforms in the intestinal contents (p < 0.05). In summary, it has been demonstrated that the inclusion of CPR in the diet induced considerable disturbances in metabolism and intestinal structure. Although CPR is a cheap protein source, its use in poultry diet does not ensure development of the intestinal structure comparable to that in the case of an SBM-only diet.

Gut Commensal Escherichia coli, a High-Risk Reservoir of Transferable Plasmid-Mediated Antimicrobial Resistance Traits

Background

Escherichia coli (E. coli), the main human gut microorganism, is one of the evolved superbugs because of acquiring antimicrobial resistance (AMR) determinants via horizontal gene transfer (HGT).

Purpose

This study aimed to screen isolates of gut commensal E. coli from healthy adult individuals for antimicrobial susceptibility and plasmid-mediated AMR encoding genes.

Methods

Gut commensal E. coli bacteria were isolated from fecal samples that were taken from healthy adult individuals and investigated phenotypically for their antimicrobial susceptibility against diverse classes of antimicrobials using the Kirby Bauer disc method. PCR-based molecular assays were carried out to detect diverse plasmid-carried AMR encoding genes and virulence genes of different E. coli pathotypes (eaeA, stx, ipaH, est, elt, aggR and pCVD432). The examined AMR genes were β-lactam resistance encoding genes (bla_CTX-M1, bla_TEM, bla_CMY-2), tetracycline resistance encoding genes (tetA, tetB), sulfonamides resistance encoding genes (sul1, sulII), aminoglycoside resistance encoding genes (aac(3)-II, aac(6′)-Ib-cr) and quinolones resistance encoding genes (qnrA, qnrB, qnrS).

Results

PCR results revealed the absence of pathotypes genes in 56 isolates that were considered gut commensal isolates. E. coli isolates showed high resistance rates against tested antimicrobial agents belonging to both β-lactams and sulfonamides (42/56, 75%) followed by quinolones (35/56, 62.5%), tetracyclines (31/56, 55.4%), while the lowest resistance rate was to aminoglycosides (24/56, 42.9%). Antimicrobial susceptibility profiles revealed that 64.3% of isolates were multidrug-resistant (MDR). High prevalence frequencies of plasmid-carried AMR genes were detected including bla_TEM (64%) sulI (60.7%), qnrA (51.8%), aac(3)-II (37.5%), and tetA (46.4%). All isolates harbored more than one gene with the most frequent genetic profile among isolates was bla_TEM-bla_CTX-M1-like-qnrA-qnrB-tetA-sulI.

Conclusion

Results are significant in the evaluation of plasmid-carried AMR genes in the human gut commensal E. coli, suggesting a potential human health risk and the necessity of strict regulation of the use of antibiotics in Egypt. Commensal E. coli bacteria may constitute a potential reservoir of AMR genes that can be transferred to other bacterial species.

Volatile Compounds and Antioxidant and Antimicrobial Activities of Selected Citrus Essential Oils Originated from Nepal

Citrus species of plants are among the most commercially cultivated crops, mainly for their fruit. Besides, the generally consumed flesh inside the fruit, the peel is quite important too. Essential oils extracted from the peel have a history of being used by humankind for centuries. These essential oils are rich in antioxidants and antimicrobial agents. Comparative investigation of volatile constituents, and antioxidant and antimicrobial activities were undertaken. The essential oils were evaluated through gas chromatography-mass spectrometry (GC-MS), and enantiomeric composition by chiral GC-MS. Similarly, the antioxidant properties were evaluated by 2,2-diphenyl-1-picrylhydrazyl scavenging assay, and antimicrobial activities were assayed using the disk diffusion method. The highest extraction yield of 1.83% was observed in Citrus sinensis Osbeck. GC-MS analysis showed limonene (63.76-89.15%), γ-terpinene (0.24-6.43%), β-pinene (0.15-6.09%), linalool (0.35-3.5%), sabinene (0.77-2.17%), myrcene (0.74-1.75%), α-terpineol (0.28-1.15%), and α-pinene (0.2-0.58%) as the major constituents of the essential oil of the Citrus species studied. For the first time, through our study, chiral terpenoids have been observed from Citrus grandis Osbeck essential oil. The order of antioxidant activity is as follows: Citrus grandis Osbeck red flesh > Citrus reticulata Blanco > Citrus sinensis Osbeck > Citrus grandis Osbeck white flesh. Except for Citrus grandis Osbeck white flesh (52.34 µL/mL), all samples demonstrated stronger antioxidant activities than those of the positive control, quercetin (5.60 µL/mL). Therefore, these essential oils can be used as a safe natural antioxidant to prevent product oxidation. Likewise, citrus peel essential oil showed antimicrobial activity against tested bacterial strains, albeit marginal.

The One Medicine concept: its emergence from history as a systematic approach to re-integrate human and veterinary medicine

The COVID-19 pandemic has resulted in the global recognition for greater inter-disciplinary and multi-disciplinary working, and the need for systematic approaches which recognise the interconnectedness and interactions between human, animal and environmental health. The notion of such a One Team/One science approach is perhaps best exemplified by the One Health concept, a systematic approach which is rapidly entering into the mainstream. However, the concept of One Health, as we presently know it, originated from One Medicine, a notion which is much older and which emerged to promote collaboration between the human and veterinary medicine professions and the allied health/scientific disciplines. Whilst One Medicine is perhaps better known by the veterinary community, some misconceptions of what One Medicine is have arisen. Therefore, this review introduces this emerging concept and how it can help to address overlapping (communicable and non-communicable disease) health challenges faced by both human and veterinary medicine.

Honeybee and Plant Products as Natural Antimicrobials in Enhancement of Poultry Health and Production

The quality and safety attributes of poultry products have attracted increasing widespread attention and interest from scholarly groups and the general population. As natural and safe alternatives to synthetic and artificial chemical drugs (e.g., antibiotics), botanical products are recently being used in poultry farms more than 60% of the time for producing organic products. Medicinal plants, and honeybee products, are natural substances, and they were added to poultry diets in a small amount (between 1% and 3%) as a source of nutrition and to provide health benefits for poultry. In addition, they have several biological functions in the poultry body and may help to enhance their welfare. These supplements can increase the bodyweight of broilers and the egg production of laying hens by approximately 7% and 10% and enhance meat and egg quality by more than 25%. Moreover, they can improve rooster semen quality by an average of 20%. Previous research on the main biological activities performed by biotics has shown that most research only concentrated on the notion of using botanical products as growth promoters, anti-inflammatory, and antibacterial agents. In the current review, the critical effects and functions of bee products and botanicals are explored as natural and safe alternative feed additives in poultry production, such as antioxidants, sexual-stimulants, immuno-stimulants, and for producing healthy products.

Antibiotic Susceptibility of Staphylococcus Species Isolated in Raw Chicken Meat from Retail Stores

The study was aimed at evaluating the presence of antibiotic-resistant Staphylococcus aureus in retailed raw chicken meat from retail stores intended for human consumption. The presence, characterization, and antibiotic susceptibility of S. aureus from 38 retail raw chicken meat samples was performed using a standard microbiological method involving mannitol salt agar (MSA) and Mueller-Hinton agar (MHA). All the samples were positive for Staphylococcus species, of which 34 (89.5%) were positive for S. aureus. The S. aureus isolates were most resistant to tetracycline (88.24%), erythromycin (82.35%), and chloramphenicol (61.77%). Nevertheless, decreased resistance towards gentamycin (23.53%) and cotrimoxazole (38.24%) were recorded. All the S. aureus isolates in this study were resistant to cloxacillin, amoxicillin, and augmentin (amoxicillin + clavulanic acid). The present findings show how the raw chicken meat samples could be a potential source of multidrug-resistant S. aureus strains dissemination. Therefore, this study suggests high-level contamination of meat with multidrug-resistant S. aureus and highlights the public health consequences of consuming such products. Undoubtedly, uncontrolled drugs in food animal production as growth stimulators or medicinal treatment present a possible consequence to people’s health. Having the aforementioned in mind, there is a necessity to control the use of drugs and monitor any residues left in the food intended for human consumption.

Antimicrobial Activity of Selected Essential Oils against Selected Pathogenic Bacteria: In Vitro Study

The worldwide problem of infectious diseases has appeared in recent years, and antimicrobial agents are crucial in reducing disease emergence. Nevertheless, the development and distribution of multidrug-resistant (MDR) strains in pathogenic bacteria, such as Escherichia coli, Staphylococcus aureus, Salmonella Typhi and Citrobacter koseri, has become a major society health hazard. Essential oils could serve as a promising tool as a natural drug in fighting the problem with these bacteria. The current study aimed to investigate the antimicrobial effectiveness of tea tree (Melaleuca alternifolia (Maiden and Betche) Cheel), rosemary (Rosmarinus officinalis L.), eucalyptus (Eucalyptus obliqua L'Hér.), and lavender (Lavandula angustifolia Mill) essential oils. The antimicrobial properties of essential oils were screened against four pathogenic bacteria, E. coli, S. aureus, S. Tyhpi, and C. koseri, and two reference bacterial strains, while for the testing, the agar well diffusion method was used. Gas chromatography (GC) and gas chromatography-mass spectrometric (GC-MSD) analyses were performed on essential oils. The obtained results showed that M. alternifolia essential oil is the richest in terpinen-4-ol, R. officinalis and E. oblique essential oils in 1,8-cineole, and L. angustifolia essential oil in α-terpinyl acetate. In addition, the main bioactive compounds present in the essential oil of tea tree are rich in α-pinene (18.38%), limonene (7.55%) and γ-terpinene (14.01%). The essential oil of rosemary is rich in α-pinene (8.38%) and limonene (11.86%); eucalyptus essential oil has significant concentrations of α-pinene (12.60%), p-cymene (3.24%), limonene (3.87%), and γ-terpinene (7.37%), while the essential oil of lavender is rich in linalool (10.71%), linalool acetate (9.60%), α-terpinyl acetate (10.93%), and carbitol (13.05%) bioactive compounds, respectively. The obtained results from the in vitro study revealed that most of the essential oils exhibited antimicrobial properties. Among the tested essential oils, tea tree was discovered to demonstrate the strongest antimicrobial activity. The recorded MIC of S. Typhi was 6.2 mg/mL, 3.4 mg/mL of C. koseri, 3.1 mg/mL of E. coli, and 2.7 mg/mL of E. coli ATCC 25922, compared to M. alternifolia. Similarly, only S. aureus ATCC 25923 showed antimicrobial activity towards R. officinalis (1.4 mg/mL), E. oblique (2.9 mg/mL), and L. angustifolia (2.1 mg/mL). Based on the obtained results, it is possible to conclude that tea tree essential oil might be used as an ecological antimicrobial in treating infectious diseases caused by the tested pathogens.

Determination of Colistin in Contents Derived from Gastrointestinal Tract of Feeding Treated Piglet and Broiler

Colistin is considered as the last-resort treatment for multiantibiotic-resistant Gram-negative bacterial infections in humans. However, the oral administration of colistin to livestock and poultry results in the introduction of large amounts of colistin to the surrounding environment via urine and feces, potentially inducing the prevalence of colistin-resistant bacteria and the impact on the ecological environment. We established a quantitative mass spectrometry (MS) based method to measure colistin in contents recovered from the gastrointestinal segments of piglets and broilers, as well as colistin in feces from the animals. The mean recoveries of colistin from different matrices were between 73.2% and 103.9%. The quantitation limit values for different matrices ranged from 0.37 to 1.85 ng/g. In colistin-treated swine samples, the highest concentration of colistin was detected in feces samples at a level of 1248.3 ng/g. However, the highest concentration of colistin in broiler samples was around 4882.9 ng/g, which was found in the contents derived from broilers' ceca. The employment of the proposed method to assess colistin in animals' gastrointestinal tracts might help to understand the colistin absorption in animals' guts and the potential impact of colistin on the emergence of resistant bacteria in animals' gut flora and the ecological environment.