[Prevalence of CTX-3 family gene among clinical isolates of Escherichia coli and Klebsiella pneumoniae from patients hospitalized in Sina Hospital, Tabriz]

Background: Emerging resistance to beta-lactam antibiotics among gram negative bacteria limits their usage. This study was done to determine the frequency of ESBLs producers and presence of CTX-M3 family gene [including CTX-M 3, 15, 22 subfamily] in Escherichia coli and Klebsiella pneumoniae isolated from different clinical specimens in Sina Hospital, Tabriz

Methods: 71 isolates of E. coli and 63 K. pneumoniae were isolated from different clinical specimens sent to Division of Microbiology, Sina Hospital, Tabriz, Iran. Bacteria were identified by conventional phenotypic methods. ESBL production in E. coli and K. pneumoniae was first detected with combined disc method using Mueller-Hinton agar and later presence of CTX-M3 family gene was detected by PCR technique

Results: In this study, 41 [57.74%] E.coli and 45 [71.42%] K. pneumoniae isolates were observed as ESBL producers. Among them, 30 [73.17%] E. coli and 26 [57.77%] K.pneumoniae were found carrying CTX-M3 gene. Among various antibiotics used for ESBL detection, highest resistance towards cefpodoxime [92%] was observed in E.coli, while in K.pneumoniae 90% isolates show resistance towards cefpodoxime and azterornam

Conclusion: Our study revealed that there is a high frequency of ESBLs producing isolates of E. coli and K. pneumoniae in our hospital set up. The problem elucidates the importance of designing more controlled surveillance of antibiotic resistance and need for large-scale epidemiologic studies to identify outcomes of the ESBL-production in gram negative bacilli

[Study of active secondary metabolites of Streptomyces levis isolated from north west soils of Iran and their in vitro and in vivo antibacterial effects]

Background: Streptomyces levis is a member of Actinomycetes family. Chemical compounds extracted from this bacterium have been used as antibiotics, anti-tumoral, anti-bacterial, anti-fungal, antiviral, anticancer factors. The purpose of this study‚ was to investigate different metabolites of Streptomyces strains isolated from north west soils, of Iran and antimicrobial effects of them

Methods: The soil samples were taken from north west of Iran in 2010. The isolated bacteria were purified and identified by conventional methods. The metabolites of this bacterium were extracted by 7 different solvents [diethyl ether, dichloromethane, hexane, ethyl acetate, chloroform, methanol and water]. The antimicrobial effects of metabolites were tested by disk agar diffusion method on Gram-positive and Gram- negative bacteria. The metabolites with antibacterial effects were analyzed by gas chromatography-mass spectrometry [GC-MS]

Results: Metabolites produced from diethyl ether solvent affected Gram- positive and Gram- negative strains and 15 different compounds identified in the active metabolite of the bacterium. The main ingredients were: Docosanoic acid, methyl ester [11.578%], 9-12-octadecadienoic acid [2.961%], 5-Tetracosenois acid, methyl ester [8.389%], Bis [2-ethylhexyl] phthalate [2.153%], and D-alpha-Tocopherol [0.959%]

Conclusion: Results of this study showed that docosanoic acid, methyl ester [11.578%] and 5-tetracosenois acid methyl ester [8.389%], were the main metabolites of Streptomyces levis isolated from north west soils of Iran. Antimicrobial effects of extracts could be due to the presence of 1, 2-benzene dicarboxylic acid diisooctyl ester compounds and bis [2-ethylhexyl] phthalate in the metabolite

[Prevalence of extended-spectrum beta-lactamases and characterization of integron class 1 in extended spectrum beta lactamase-producing Klebsiella pneumoniae in Sina Hospital, Tabriz 2012]

Background: The existence of beta-lactmase among gram-negative bacteria such as Klebsiella pneumoniae, as a significant pathogen in nosocomial infection is the most important cause of resistance against beta- lactam antibiotics family. Class 1 integrons are mobile genetic elements which are mostly prevalent in drug-resistant bacteria. This study was conducted to determine the prevalence of phenotypic and genotypic ESBL-producing strains as well as the incidence of integron class 1 in ESBL-producing strains

Methods: Sixty three isolates of K.pneumoniae, confirmed by biochemical and phenotypic tests, were collected within six months. Susceptibility test was carried out by Disk diffusion method. Prevalence of ESBL producing strains were determined by using Combined Disk Test. Presence of bla TEM, bla SHV gene family and class I integron were detected by PCR technique

Results: Forty five [71.4%] of isolates were ESBL-producing. TEM and SHV gene family were existed in 66.6% and 68.9% of ESBL -producing isolates, respectively. Class I integron were detected in 24 [65%] and 19 [63.3%] of SHV and TEM positive strains, respectively

Conclusion: In present study, increasing level of ESBL producing isolates were confirmed. Also, this study intensely demonstrates the role of integron in the dissemination of ESBL-mediated resistance among the nosocomial isolates. Overall, using the proper treatment procedure according to the antibiogram pattern of the strains is specifically recommended