ABSTRACT
Acanthamoeba genus includes pathogenic species which are causal agents of a severe sight-threatening infection of the eye known as Acanthamoeba keratitis (AK). Furthermore, the number of AK is worryingly increasing worldwide, mostly in contact lens users. Until present, there is a general failure to reach a fully effective treatment against AK which is mainly due to the amoebic double-walled cyst stage which forms a protective barrier against drugs. Therefore, drug discovery research towards AK treatment is a must. In this study, Ziziphus vulgaris, a native plant of Asian countries, was checked for its activity against Acanthamoeba. For this purpose and in order to determine the in vitro amoebicidal effects of Ziziphus vulgaris aqueous extract and its fractions (chloroformic, remaining aqueous and primary alcoholic) against Acanthmoeba trophozoites and cysts, activity and sensitivity assays were performed. Moreover, the toxic effect of the extract and its fractions was also tested on murine peritoneal macrophages using a colorimetric tetrazolium salt (MTT) test. The obtained results showed that the chloroformic fraction presented a higher anti-Acanthamoeba activity when compared to the other fractions (Trophozoites/cysts were eliminated, when incubated in a concentration of 50 mg/ml of the fraction, after 24 hours). The calculated active concentrations against Acanthamoeba of these extracts did not shown any high cytotoxicity levels.This study suggests that the Ziziphus vulgaris chloroformic fraction, may present compounds with relevance for the development of novel antiAcanthamoeba drugs.
ABSTRACT
OBJECTIVE: To investigate the antimicrobial susceptibility patterns of Pseudomonas aeruginosa clinical isolates and their associations with the existence of integrons. METHODS: During a 12-month study, 140 clinically significant Pseudomonas aeruginosa isolates were collected from patients hospitalized in the burn ward of different hospitals in Tehran. Pseudomonas aeruginosa isolates were identified using standard laboratory procedures. Antimicrobial susceptibility testing was performed for 13 antimicrobial agents according to the standard Kirby-Bauer disk diffusion method and Clinical and Laboratory Standards Institute (CLSI) guidelines. The frequency of Class 1, 2 and 3 integrons was detected using a polymerase chain reaction (PCR) method. RESULTS: The resistance rates of Pseudomonas aeruginosa isolates to 13 antimicrobial agents were between 34.7% and 90.8%. Ceftriaxone and imipenem had good activity against the isolates. Of 140 tested isolates, 91 (65%) were multidrug resistant. The most predominant resistance profile among the isolates included resistance to 10 (12.14%), 9 (12.14%) and 8 (12.14%) antibiotics. Class 1 and 2 integrons were detected in 57.2% (56/98) and 30.6% (30/98) of tested Pseudomonas aeruginosa isolates, respectively. Of 98 (70%) integron positive isolates, only 12 (12.2%) isolates were positive for both classes of integrons. Resistance of the isolates to cefotaxime, aztreonam, imipenem, tobramycin, ticarcillin, ciprofloxacin and cloxacillin was observed to be significantly associated with the existence of integrons. CONCLUSION: These data confirmed high prevalence of Class 1 integrons among Pseudomonas aeruginosa isolates from burn patients in this study. Based on these results, integrons may play an important role in the possible transmission of resistance genes to the clinical Pseudomonas aeruginosa isolates.
