Epidemiology and Traits of Mobile Colistin Resistance (mcr) Gene-Bearing Organisms from Horses.

Mobile colistin resistance (mcr) genes (mcr-1 to mcr-10) threaten the efficacy of colistin (COL), a polymyxin antibiotic that is used as a last-line agent for the treatment of deadly infections caused by multidrug-resistant and extensively drug-resistant bacteria in humans and animals. COL has been used for more than 60 years for the prophylactic control and treatment of infections in livestock husbandry but not in horses. Polymyxin B is used for the prophylactic control and empirical treatment of infections in horses without conducting sensitivity tests. The lack of sensitivity testing exerts selection pressure for the acquisition of the mcr gene. By horizontal transfer, mcr-1, mcr-5, and mcr-9 have disseminated among horse populations globally and are harbored by Escherichia coli, Klebsiella, Enterobacter, Citrobacter, and Salmonella species. Conjugative plasmids, insertion sequences, and transposons are the backbone of mcr genes in the isolates, which co-express genes conferring multi- to extensive-drug resistance, including genes encoding extended-spectrum ß-lactamase, ampicillinase C, fosfomycin, and fluoroquinolone resistance, and virulence genes. The transmission of mcr genes to/among bacterial strains of equine origin is non-clonal. Contact with horses, horse manure, feed/drinking water, farmers, farmers' clothing/farm equipment, the consumption of contaminated horse meat and its associated products, and the trading of horses, horse meat, and their associated products are routes for the transmission of mcr-gene-bearing bacteria in, to, and from the equine industry.

A New Variant of Mutational and Polymorphic Signatures in the ERG11 Gene of Fluconazole-Resistant Candida albicans.

Background: Resistance to antifungal drugs for treating Candida infections remains a major concern globally despite the range of medications available. Most of these drugs target key proteins essential to the life cycle of the organism. An enzyme essential for fungal cell membrane integrity, lanosterol 14-α demethylase (CYP51), is encoded by the ERG11 gene in Candida species. This enzyme is the target of azole-based drugs. The organism has, however, devised molecular adaptations to evade the activity of these drugs. Materials and Methods: Classical methods were employed to characterize clinical isolates sampled from women and dogs of reproductive age. For fluconazole efficacy studies, CLSI guidelines on drug susceptibility testing were used. To understand the susceptibility pattern, various molecular and structural analytic approaches, including sequencing, in silico site-directed mutagenesis, and protein-ligand profiling, were applied to the ERG11 gene and CYP51 protein sequences. Several platforms, comprising Clustal Omega, Pymol plugin manager, Pymol molecular visualizer, Chimera-curated Dynameomics rotamer library, protein-ligand interaction profiler, Charmm36 force field, GROMACS, Geneious, and Mega7, were employed for this analysis. Results: The following Candida species distribution was obtained: 37.84% C. albicans, 8.12% C. glabrata, 10.81% C. krusei, 5.41% C. tropicalis, and 37.84% of other unidentified Candida species. Two codons in the nucleotide sequence of the wild-type (CTC and CCA) coding for LEU-370 and PRO-375, respectively, were mutated to L370S and P375H in the resistant strain. The mutation stabilized the protein at the expense of the heme moiety. We found that the susceptible isolate from dogs (Can-iso-029/dog) is closely related to the most resistant isolate from humans. Conclusion: Taken together, our results showed new mutations in the heme-binding pocket of caCYP51 that explain the resistance to fluconazole exhibited by the Candida isolates. So far, the L370S and P375H resistance-linked mutations have not been previously reported.

Reduction of the Adverse Impacts of Fungal Mycotoxin on Proximate Composition of Feed and Growth Performance in Broilers by Combined Adsorbents.

Synergistic interaction of adsorbents in reducing the adverse impacts of mycotoxin on performance and proximate composition of broiler feeds was investigated. Fungal growth was induced by sprinkling water on the feed. S. cerevisiae + bentonite, kaolin + bentonite or S. cerevisiea + kaolin adsorbent combinations (1.5 g/kg feed) were added and the feeds were stored in black polythene bags. An untreated group was kept as a positive control while fresh uncontaminated feed was used as a negative control. Mycotoxins were extracted from the feeds and quantified using reverse phase HPLC. Proximate composition, nutrient digestibility of the feeds, feed intake and weight gain of the broilers were measured. Deoxynivalenol (DON) concentration in the contaminated/untreated feed was 347 µg/kg while aflatoxin B1 (AFB1) was 34 µg/kg. Addition of bentonite and kaolin in the contaminated feed reduced AFB1 and DON to significantly lower levels. Feed intake and weight gain were low in the broilers fed the contaminated feed. The carbohydrate level was significantly (p < 0.05) reduced from 62.31 to 40.10%, crude protein digestibility dropped from 80.67 to 49.03% in the fresh feed and contaminated feed respectively. Addition of the adsorbents (S. cerevisiae and bentonite) significantly (p < 0.05) improved these parameters.

Saccharomyces cerevisiae, bentonite, and kaolin as adsorbents for reducing the adverse impacts of mycotoxin contaminated feed on broiler histopathology and hemato-biochemical changes.

BACKGROUND AND AIM: Saccharomyces cerevisiae, bentonite and kaolin were used to reduce the adverse effects of mold-contaminated diet on broilers. The aim of the study was to evaluate the impact of S. cerevisiae, bentonite, and kaolin in reducing the adverse effects of mold (fungal) contaminated diet on broilers. Specifically, we investigated the histopathological, hematological, and serum biochemical changes associated with broilers fed mold-contaminated diets supplemented with these three adsorbents. We also isolated and identified the common fungal contaminants in the poultry feeds as well as the mycotoxins they produced. MATERIALS AND METHODS: Hundred broilers (3-weeks-old) were randomly grouped into five dietary treatments, basal feed (negative control), feed contaminated with mold, mold-contaminated feed+S. cerevisiae, mold-contaminated feed+bentonite, and mold-contaminated feed+kaolin. The fungal contaminants in the feeds were isolated and molecularly identified while the mycotoxins in the feed where analyzed using high-performance liquid chromatography. Blood samples of birds from each group were analyzed for hematology and serum biochemistry. The liver, spleen, kidney, and bursa of Fabricius of the birds were excised and analyzed for histopathological changes. RESULTS: The most common fungal contaminants in the feeds were Penicillium (33.3%) species, followed by Aspergillus species (22.2%). The mold-contaminated feed had the highest number of fungal contaminants, 55.6%, while the negative control (basal feed group) had none. Total aflatoxin and deoxynivalenol were high in the mold-contaminated feed (53.272 µg/kg and 634.5 µg kg, respectively), but these were reduced by the addition of adsorbents to the feed. The birds fed mold-contaminated feed had significantly (p<0.05) reduced red blood cell count counts, packed cell volume, and hemoglobin but increased white blood cell count compared to the negative control. Liver enzyme activity (alanine transaminase, aspartate aminotransferase, and alkaline phosphatase) and cholesterol concentration increased significantly (p<0.05) in the group fed mold-contaminated feed while the serum albumin and total protein decreased significantly (p<0.05) in comparison with the negative control. Adverse histopathological changes were observed in the liver, kidney, spleen, and bursa of Fabricius in the group fed mold-contaminated feed. Addition of S. cerevisiae, bentonite or kaolin in the mold-contaminated feed ameliorated these toxic effects. CONCLUSION: The observed histopathological lesions were consistent with mycotoxicosis in birds and were mild in the adsorbent treated groups. Kaolin had a higher protective effect against mycotoxicosis than the two other adsorbents.

Occurrence and antibiogram of Listeria species in raw pork, beef, and chicken meats marketed in Enugu State, Southeast Nigeria.

AIM: This study was undertaken to isolate Listeria (L.) species from raw meats sold in markets in Enugu State, Southeast Nigeria, and to determine the antibacterial resistance profile. MATERIALS AND METHODS: Twenty-five grams of beef (n=144), chicken meat (n=144), and pork (n=144) were collected randomly from supermarkets and general markets in Enugu State. Isolation of Listeria was done using half and full Fraser broths, and polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol agar. Identification of isolates was done using an analytical profile index kit specific for Listeria. Confirmation of the genus Listeria was done by a polymerase chain reaction. The resistance of the isolates was determined using the disk diffusion method. RESULTS: Listeria was isolated from 39/144 (27.1%) chicken meat, 19/144 (13.2%) pork, and 66/144 (45.8%) beef samples cultured. Listeria innocua was the predominant species in chicken meat (52.6%) and beef (81.8%) samples. Listeria grayi, Listeria welshimeri, and Listeria ivanovii were also isolated from the beef and chicken meat samples. More than 65% of the isolates were resistant to penicillin, rifampicin, ciprofloxacin, sulfamethoxazole-trimethoprim, and cephalothin. All the isolates from beef and pork samples and 23 (92%) from chicken meat samples, were resistant to ≥3 classes of antibacterial agents. Mean multiple antibiotic resistance index (MARI) was 0.77 (range=0.42-1.00), 0.58 (range=0.25-0.83), and 0.79 (range=0.58-0.92) for the isolates from beef, chicken meat, and pork samples, respectively. All the isolates had MARI >0.2. CONCLUSION: Multidrug-resistant Listeria strains contaminate raw beef, pork, and chicken meats marketed in Enugu State, Southeast Nigeria.