RESUMO
Evidence of increasing resistance to antibiotics in soil and other natural isolates highlights the importance of horizontal transfer of resistance genes in facilitating gene flux in bacteria. Horizontal gene transfer in bacteria is favored by the presence of mobile genetic elements and by the organization of bacterial genomes into operons allowing for the cooperative transfer of genes with related functions. The selective pressure for the spread of resistance genes correlates strongly with the clinical and agricultural overuse of antibiotics. The future of antimicrobial chemotherapy may lie in developing new antimicrobials using information from comparative functional microbial genomics to find genetic targets for antimicrobials and also to understand gene expression enabling selective targeting of genes with expression that correlates with the infectious process.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Antibacterianos/uso terapêutico , Bactérias/efeitos dos fármacos , Bactérias/genética , Infecções Bacterianas/tratamento farmacológico , Conjugação Genética , Farmacorresistência Bacteriana/genética , Evolução Molecular , PlasmídeosRESUMO
Bacteria isolates belonging to the genera Bacillus, Corynebacterium, Aeromonas, and Enterobacter were isolated from a municipal waste landfill in Durham, NC. Bacterial counts obtained with three general purpose media were log(10) colony-forming units (cfu)/g of 9.30, 9. 26, and 9.20 respectively for Plate Count Agar, Brain Heart Infusion Agar, and Nutrient Agar. Coliform count from MacConkey agar was log(10) 7.28/g sample. Isolates were generally sensitive to tetracycline and chloramphenicol (13 of 14 isolates) and generally resistant to ampicillin (9 of 9), erythromycin (10 of 14), streptomycin (8 of 14), with 3 of 14 isolates having multiple resistance to the last three antibiotics. A dose-independent growth response to ampicillin was observed for two isolates. The detection of a 22,000-bp plasmid in one but not in the second ampicillin-resistant isolate suggests more than one mechanism of antibiotic resistance.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Plasmídeos , Eliminação de Resíduos , Bactérias/genética , Contagem de Colônia Microbiana , Enzimas de Restrição do DNA/metabolismo , Resistência Microbiana a Medicamentos , Testes de Sensibilidade MicrobianaRESUMO
Sixteen samples each of various beef parts including muscle, liver, kidney, heart, and intestines from a local market in Awka, Anambra State of Nigeria were analysed for presence of coagulase-positive Staphylococcus . A total of 80 meat samples was evaluated of which 54 samples or 67.5% had coagulase-positive staphylococci. The percentage of the various meat samples that had coagulase-positive staphylococci was 18.8% for muscle, 75% for liver, 68.8% for kidney, 75% for heart and 100% for intestinal samples. Muscle tissue had the lowest staphylococcal count log (1.65 - 2.97/g), whereas intestinal samples had the highest count (log 5.88 - 6.97g). The organ meats had staphylococcal counts of log 3.10 - 4.89/g for liver samples, log 3.27 - 4.75/g for kidney samples and log 3.15 - 4.90/g for heart samples.
