ABSTRACT
ABSTRACT The main mechanism of quinolone resistance in Klebsiella (K) pneumoniae is caused by mutation of porin-related proteins and efflux pumps. This study aimed to investigate the prevalence of ciprofloxacin-resistant K pneumoniae in burns patients and to understand the role of the AcrAB multidrug efflux system on minimal inhibitory concentration (MIC) of ciprofloxacin. For this reason, 52 K pneumoniae samples were collected from burns patients and evaluated for the mechanism of ciprofloxacin resistance. The results demonstrated that 40 isolates of K pneumoniae were ciprofloxacin-resistant and 35 showed the mutation on gyrA locus. By inhibition of the efflux system, the MIC yield showed a significant decrease. Therefore, it could be concluded that the high rate of mutation on the gyrA locus in combination with quinolone resistance was responsible for ciprofloxacin resistance and by inhibition of AcrA, the resistance rate showed a significant decrease in K pneumoniae isolated from burns patients.
RESUMEN El principal mecanismo de resistencia a la quinolona en las Klebsiella (K) Pneumoniae tiene como causa la mutación de las porinas y las bombas de eflujo. Este estudio tuvo por objetivo investigar la prevalencia de las K pneumoniae resistentes a la ciprofloxacina en pacientes con quemaduras, así como entender el papel del sistema de eflujo multidroga AcrAB en la concentración inhibitoria mínima (CIM) de la ciprofloxacina. Por esta razón, se recogieron 52 muestras de K pneumoniae de pacientes con quemaduras, a fin de evaluar el mecanismo de resistencia a la ciprofloxacina. Los resultados mostraron que 40 aislados de K pneumoniae eran resistentes a la ciprofloxacina y 35 mostraron la mutación en el locus gyrA. Con la inhibición del sistema de eflujo, el rendimiento de CIM tuvo una disminución significativa. Por lo tanto, se pudo concluir que la alta tasa de mutación en el locus gyrA en combinación con la resistencia a la quinolona era responsable de la resistencia a la ciprofloxacina, y por la inhibición de AcrA, la tasa de resistencia mostró una disminución significativa en las K pneumoniae aisladas de los pacientes con quemaduras.
Subject(s)
Humans , Male , Female , Burns/microbiology , Ciprofloxacin/pharmacology , Drug Resistance, Bacterial/genetics , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/genetics , Mutation/genetics , Microbial Sensitivity TestsABSTRACT
Herbal medicines are defined as traditionally used natural products. The current study in an attempt try to investigate the antibacterial activity on extended spectrum beta-lactamases (ESBL), methalo beta-lactamases (MBL) producing gram negative bacteria and methicillin resistant Staphylococcus aureus (MRSA) and subsequently, to determine the antioxidant activity of Thymus daenensis. For this reasons, firstly cytotoxicity of T. daenensis was determined by MTT assay. Then, essential oil was subjected for antibacterial and antioxidant activity. Our results demonstrated that 15 mg/ml concentration of T. daenensis inhibited both P. aeruginosa producing MBL and E.coli producing ESBL, while this value was 25 mg/ml concentration for MRSA inhibition. The association between phenolic compound and antioxidant activity was found for the ABTSâ¢+ method (43.52%) in the lowest level, while, for FRAD and DPPH⢠methods the opposite story occurred (70.5% correlation for DPPH⢠and 50.9% for FRAD). Our findings suggested that T. daenensis has a potential herbal medicine that should be considered as an antibacterial and antioxidant with very low toxicity.
Subject(s)
Anti-Bacterial Agents/pharmacology , Antioxidants/pharmacology , Plant Extracts/pharmacology , Plants, Medicinal/chemistry , Thymus Plant/chemistry , Animals , Cell Line , Escherichia coli/drug effects , Microbial Sensitivity Tests/methods , Oils, Volatile/chemistry , Phenols/chemistry , Phytotherapy/methods , Pseudomonas aeruginosa/drug effects , Vero CellsABSTRACT
Presently, there is an increase in antibiotic resistance in bacteria, due to relax prescription of antibiotics, especially in Iran. Undoubtedly, in toxin antitoxin (TA) system, a toxin neutralized by antitoxin, which known as a potent antimicrobial target; but there is no extensive survey on the prevalence of TA loci in large scale of Klebsiella pneumoniae. Therefore, this study aims to determine the prevalence of different TA loci in clinical and environmental K. pneumoniae isolates. For this reason, 48 K. pneumoniae clinical isolates and 49 K. pneumoniae environmental isolates were subjected for evaluation of different TA loci. The results of current study indicated that there is no association between antibiotic resistances and presence of TA loci in clinical and environmental K. pneumoniae. The role of TA loci as a potent target in antibiotic resistant K. pneumoniae has been complicated. Therefore, more studies should be performed to explain why TA loci are presented in K. pneumoniae and what is the rationale behind antibiotic resistant K. pneumoniae?
