RESUMEN
Eighty-three swine isolates of Campylobacter coli were tested for mechanisms underlying resistance to nalidixic acid, ciprofloxacin, erythromycin and tetracycline. Four isolates harbored class 1 integrons but none carried class 2 and 3 integrons. Most of the tetracycline-resistant isolates (97%) possessed tet(O). A Thr-86-Ile substitution in GyrA and an A-2230-G mutation in 23S rRNA were the main resistance mechanisms for quinolones and erythromycin, respectively.
Asunto(s)
Antibacterianos/farmacología , Infecciones por Campylobacter/veterinaria , Campylobacter coli/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Integrones , Enfermedades de los Porcinos/tratamiento farmacológico , Animales , Infecciones por Campylobacter/tratamiento farmacológico , Infecciones por Campylobacter/microbiología , Infecciones por Campylobacter/transmisión , Campylobacter coli/genética , Campylobacter coli/aislamiento & purificación , Recuento de Colonia Microbiana , Relación Dosis-Respuesta a Droga , Microbiología de Alimentos , Humanos , Carne/microbiología , Pruebas de Sensibilidad Microbiana , Mutación , ARN Ribosómico 23S/genética , Especificidad de la Especie , Porcinos , Enfermedades de los Porcinos/microbiología , Enfermedades de los Porcinos/transmisión , ZoonosisRESUMEN
There is broad consensus internationally that surveillance of the levels of antimicrobial resistance (AMR) occurring in various systems underpins strategies to address the issue. The key reasons for surveillance of resistance are to determine (i) the size of the problem, (ii) whether resistance is increasing, (iii) whether previously unknown types of resistance are emerging, (iv) whether a particular type of resistance is spreading, and (v) whether a particular type of resistance is associated with a particular outbreak. The implications of acquiring and utilizing this information need to be considered in the design of a surveillance system. AMR surveillance provides a foundation for assessing the burden of AMR and for providing the necessary evidence for developing efficient and effective control and prevention strategies. The codevelopment of AMR surveillance programs in humans and animals is essential, but there remain several key elements that make data comparisons between AMR monitoring programs, and between regions, difficult. Currently, AMR surveillance relies on uncomplicated in vitro antimicrobial susceptibility methods. However, the lack of harmonization across programs and the limitation of genetic information of AMR remain the major drawbacks of these phenotypic methods. The future of AMR surveillance is moving toward genotypic detection, and molecular analysis methods are expected to yield a wealth of information. However, the expectation that these molecular techniques will surpass phenotypic susceptibility testing in routine diagnosis and monitoring of AMR remains a distant reality, and phenotypic testing remains necessary in the detection of emerging resistant bacteria, new resistance mechanisms, and trends of AMR.
Asunto(s)
Farmacorresistencia Bacteriana , Monitoreo Epidemiológico/veterinaria , Vigilancia de Guardia/veterinaria , Animales , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Bacterias/genética , Bacterias/patogenicidad , Infecciones Bacterianas/epidemiología , Infecciones Bacterianas/microbiología , Infecciones Bacterianas/veterinaria , Farmacorresistencia Bacteriana/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Genes Bacterianos , Humanos , Ganado , Metagenómica/métodos , Pruebas de Sensibilidad Microbiana , Técnicas de Diagnóstico Molecular , Zoonosis/epidemiología , Zoonosis/microbiologíaRESUMEN
The contribution of efflux pumps to multidrug resistance in 12 Pseudomonas aeruginosa isolates from various animal sources was assessed. Western immunoblot analyses demonstrated that all twelve isolates expressed significant levels of the MexAB OprM efflux system whereas two isolates simultaneously expressed the MexEF OprN or MexXY systems, respectively. One strain contained a single mutation in mexR, a regulator of mexAB-oprM expression, that did not adversely affect the MexR amino acid sequence, and three isolates contained the same, single base change in the mexA-mexR intergenic region. The MexXY-expressing strain contained two base substitutions in its mexZ regulatory gene which did not alter the MexR sequence.
Asunto(s)
Proteínas Bacterianas , Farmacorresistencia Microbiana/genética , Resistencia a Múltiples Medicamentos/genética , Proteínas de Transporte de Membrana , Infecciones por Pseudomonas/veterinaria , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/genética , Proteínas Represoras/genética , Secuencia de Aminoácidos , Animales , Antibacterianos/farmacología , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Secuencia de Bases , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Regulación Bacteriana de la Expresión Génica , Intrones , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/aislamiento & purificación , Proteínas Represoras/química , Proteínas Represoras/metabolismoRESUMEN
Triclosan is an antiseptic frequently added to items as diverse as soaps, lotions, toothpaste, and many commonly used household fabrics and plastics. Although wild-type Pseudomonas aeruginosa expresses the triclosan target enoyl-acyl carrier protein reductase, it is triclosan resistant due to expression of the MexAB-OprM efflux system. Exposure of a susceptible Delta(mexAB-oprM) strain to triclosan selected multidrug-resistant bacteria at high frequencies. These bacteria hyperexpressed the MexCD-OprJ efflux system due to mutations in its regulatory gene, nfxB. The MICs of several drugs for these mutants were increased up to 500-fold, including the MIC of ciprofloxacin, which was increased 94-fold. Whereas the MexEF-OprN efflux system also participated in triclosan efflux, this antimicrobial was not a substrate for MexXY-OprM.