An investigation of the occurrence of antibiotic resistance genes among strains of <i>Staphylococcus aureus</i> isolated from animals and their relationship to human strains of <i>Staphylococcus aureus</i>

Data has emerged which indicates that antimicrobial use in animals has created a reservoir of resistant bacteria and resistance genes that have spread to humans. The aim of this study was to examine the influence of animal antimicrobial use on human strains of S. aureus. Phenotypic and genotypic methods assessed the genetic population structure, potential for host adaptation, frequency of antimicrobial resistance, presence and frequency of genes encoding tetracycline and macrolide resistance and structural variation in tetK genes in S. aureus from animals compared with human clinical strains. In addition, the transferability of tetK resistance plasmids from animal strains to S. aureus 8325-4 was investigated. DNA based typing exhibited 100% typeability, high levels of discrimination and a high degree of concordance between methods. Multi-locus sequence typing (MLST) identified six sequence types (CC5, CC15, CC22, CC25, CC30 and CC45) common to both isolate collections that represented four of the five major human methicillin resistant Staphylococcus aureus (MRSA) clonal lineages. The relatedness of these clones was further supported by the analysis of 20 different virulence determinants. Isolates of CC5 exhibited resistance to ciprofloxacin, clindamycin, erythromycin, penicillin, streptomycin, tobramycin and tylosin, CC 15 to penicillin and tetracycline, CC22 to penicillin and rifampicin and CC30 to penicillin. Isolates of CC45 were fully susceptible. Low level biocide resistance was detected but the significance of this was unclear. The tetK and ermC genes were the predominant tetracycline and macrolide resistance genes. tetK was harboured by animal isolates of CC5 and CC15 and ermC by animal isolates of CC5. Restriction fragment length polymorphism (RFLP) of tetK amplicons produced indistinguishable restriction patterns. High frequency transfer of a tetK plasmid from a chicken S. aureus (CC5) to S. aureus 8325-4 was observed. These data support the hypothesis that animals represent an important reservoir of antibiotic resistant S. aureus with the ability for strain and antibiotic resistance gene transfer to humans

Influence of antibiotic treatment duration on the development of antibiotic resistance

Avoidance of unnecessary antimicrobial administration is a key point of antimicrobial stewardship; knowing the optimal duration of therapy obviates over-treatment. In this article we have highlighted the results of modern research on the influence of the duration of antibiotic use on the success of treatment and the development of resistance of microorganisms. Foreign literary sources and the results of scientific research by experts in this field are analyzed. Based on the research results, the following conclusions were made. The results of modern studies on the duration of antibiotic use show that short-course antibiotic therapy is superior to usual long-course antimicrobial treatment. A short course of antibiotic therapy usually leads to the same positive clinical outcomes, a lower rate of antibiotic resistance and the number of clinical relapses. The two most important potential complications associated with the duration of antibiotic therapy are incomplete treatment and the emergence of antibiotic resistance. The time points used for antibiotic treatment (clinical or bacteriological cure, relapses, etc.) are subjective, complex and unreliable. The effectiveness of procalcitonin or other blood parameters for use in monitoring antibiotic treatment requires more focused studies. Despite the high relevance and publicity of various aspects of antibiotic therapy in the practice of human and animal healthcare, research on the efficacy and consequences of short-term antibiotic therapy in veterinary medicine is limited. More attention should be paid to this issue, especially in the field of animal husbandry

Monitoring and Surveillance of Veterinary Antimicrobial Use and Antibiotic Resistance in Animals

Antimicrobial resistance is a global One Health topic that affects us all, whether we are working in human or veterinary medicine. Although antibiotic use in farm animals is decreasing in many countries, other nations are still using these essential medical resources as growth promoters to boost economic gains. As veterinarians responsible for animal welfare, it is vital that we are permitted to treat sick animals effectively, but we must learn to be more prudent in our use of these drugs. It is essential that we, as responsible clinicians, policy makers, and researchers, develop methods of quantifying, monitoring, benchmarking, and reporting antibiotic use in both farm and companion animals, so that antimicrobial stewardship schemes can be implemented and their successes or failures analyzed. This Special Issue includes research on antibiotic use and resistance in a variety of animal species, covering cattle, sheep, pigs, poultry, and pets. The relationship between antimicrobial use and resistance in animals is investigated on a global scale, with authors from Austria, Australia, Brazil, Germany, Italy, India, the Netherlands, Peru, Portugal, Slovenia, and the United Kingdom

Spartan Daily, December 9, 1975

Volume 65, Issue 51https://scholarworks.sjsu.edu/spartandaily/6031/thumbnail.jp