Shirin Sheikholeslami , Seyed Mahdi Rezayat , Reza Hosseini Doust , Hamid Reza Ahmadi Ashtiani ,
Volume 10, Issue 1 (1-2016)
Abstract
Abstract
Background and Objective: The spread of drug resistance in bacteria have prompted researchers to seek suitable alternative for antimicrobial drugs among various medicinal plants and nanoparticles. The aim of this study was to evaluate the effect of silver nanoparticles alone and in combination with methanol extract of Zataria multiflora on five Gram-positive and Gram-negative bacteria.
Methods: Different concentrations of the nanoparticles and extract alone or in combination with each other were tested against the bacteria, using well diffusion method. Three concentration levels (lowest, average and highest) were prepared form the nanoparticles and the extract for the combination, and finally nine different combinations were prepared.
Results: The extract and nanoparticles showed inhibitory effects against all the tested bacteria. The maximum diameter of growth inhibition zone in the presence of the extract and nanoparticles were observed in Streptococcus pyogenes (35.6mm) and methicillin-resistant Staphylococcus aureus (20.6mm), respectively. The maximum diameter of growth inhibition zone for the combination was measured in S. pyogenes (31mm).
Conclusion: The combination of low concentrations of the plant extract and nanoparticles are more effective against bacteria, but the combination of their high concentrations reduce the antibacterial effects in some cases.
Mobina Hosseini, Meysam Hasannejad-Bibalan, Tofigh Yaghoubi, Mohammadreza Mobayen, Parisa Khoshdoz, Sara Khoshdoz, Niloofar Faraji, Hadi Sedigh Ebrahim-Saraie,
Volume 15, Issue 6 (11-2021)
Abstract
Background and objectives: Bacterial contamination of wounds is a serious problem, particularly in burn patients. Gram-positive bacteria are the predominant cause of infection in newly hospitalized burn cases. This study aimed to survey the prevalence and antibiotic resistance pattern of gram-positive bacterial isolates among burn patients in Rasht, North of Iran.
Methods: This cross-sectional study was conducted on burn patients with a positive culture for gram-positive isolates who were hospitalized in the Velayat Burn Center in Rasht, North of Iran, during 2017-2020. The isolates were identified using standard microbiological methods. Moreover, the antibiotic resistance pattern was determined by the disk diffusion method.
Results: During the study period, 671 bacterial cultures were obtained, of which a total of 16 gram-positive isolates were taken from the patients. The frequency of coagulase-negative staphylococci (CoNS), Staphylococcus aureus, and Enterococcus spp. was 68.7%, 18.8%, and 12.5%, respectively. In addition, the highest rate of resistance in CoNS isolates was against trimethoprim/sulfamethoxazole. The highest rate of resistant among S. aureus isolates was recorded against penicillin. Moreover, Enterococcus faecalis isolates showed a high level of resistance to ampicillin, erythromycin, tetracycline, gentamicin, and ciprofloxacin. All isolates were susceptible to teicoplanin. Moreover, the frequency of methicillin-resistant S. aureus isolates was 66.7%.
Conclusion: Given the increasing prevalence of drug-resistant strains, especially in susceptible burn patients, it is imperative to analyze the bacterial etiology of nosocomial infections periodically and epidemiologically.
