Azad Khaledi - Academia.edu (original) (raw)

Papers by Azad Khaledi

Journal of Infection and Public Health, 2016

The spa gene occurs in all strains of Staphylococcus aureus (S. aureus), can function as a geneti... more The spa gene occurs in all strains of Staphylococcus aureus (S. aureus), can function as a genetic marker and might be used distinguish strains at the species level. Hence, due to these advantages, we used spa typing and the Based Upon Repeat Pattern (BURP) to assign the clonal and phylogenetic relationships of S. aureus strains. The sensitivity of S. aureus strains to methicillin was determined using agar disk diffusion. The extracted DNA from 56 isolates of S. aureus was subjected to PCR to detect the spa gene with specific primers. The spa typing method was performed for each of the isolates, and then, BURP was used to cluster spa types (spa-CCs). Finally, using relevant software, the phylogenic tree was drawn. The results of this study showed that 25 out of 56 (44.6%) isolates were resistant to methicillin. The typing of S. aureus isolates revealed 24 different spa types among 56 isolates, and BURP analysis clustered the 24 spa types into 5 spa clonal complexes (CCs) and 12 singletons. The process of spa typing, in combination with BURP analysis, provides an efficient method for investigating phylogenetic and clonal relationships among clinical isolates and can be useful for monitoring bacterial spread between hospitals and communities as well as between and within hospitals.

Avicenna Journal of Clinical Microbiology and Infection, 2016

Avicenna Journal of Clinical Microbiology and Infection, Feb 1, 2015

Background: Infection due to Acinetobacter baumannii has become a significant challenge to modern... more Background: Infection due to Acinetobacter baumannii has become a significant challenge to modern healthcare systems. The rapid emergence and global dissemination of A. baumannii as a major nosocomial pathogen is remarkable and it demonstrates its successful adaptation to the 21st century hospital environment. Recent studies have discussed about essential oil of Origanum vulgare against a range of bacteria, including various species of Staphylococcus, Pseudomonas, Bacillus and Escherichia coli. Objectives: The present study aimed to investigate the inhibitory effects O. vulgare essence against multidrug-resistant (MDR) strains of A. baumannii from selected hospitals in Tehran, Iran. Materials and Methods: This oil was obtained using the hydrodistillation method and analyzed by gas chromatography mass spectrography (GC/MS). The antimicrobial activity against MDR isolates was achieved using disc diffusion method and macro-broth dilution assay. Results: Analysis of the essential oil revealed the presence of pulegone (68.59%) piperitone (7.8%), piperitenone (7.8%), 1, 8-cineole (1.3%), and carvacrol (1.6%) as the major components. The results showed a significant activity against MDR A. baumannii with inhibition zones and minimal inhibitory concentration values in the ranges of 7-15 mm and 20-35 µL/mL respectively. Conclusions: This investigation showed that the essence oil of O. vulgare had a potent antimicrobial activity against MDR A. baumannii. Further research is required to evaluate the practical values of therapeutic applications.

Multidrug-resistant strains of Acinetobacter baumannii have emerged as formidable nosocomial path... more Multidrug-resistant strains of Acinetobacter baumannii have emerged as formidable nosocomial pathogens, particularly among patients with pneumonia in intensive care units (ICUs) with a high mortality rate. In this study 100 A. baumannii isolates from patients in tertiary ICUs of Shiraz university hospital in southwest of Iran were selected and tested for susceptibility to 24 antimicrobials and multiplex PCR methods were used to determine virulence factors and International Clone (IC) of A. baumannii isolates. Considerable number of the isolates (68%) belonged to IC2, which was widespread in all ICUs. Twenty-one (21%) isolates pertained to IC1. Eleven of the isolates (11%) belonged to 3 novel variant of SG4-6. Drug resistance pattern showed that MDR and XDR phenotype proportion among isolates was 75% and 18%, respectively. 13% of the A. baumannii isolates were resistant to colistin. All of the isolates were positive for both the pld and the pgaB virulence genes tested. The prevalence of ptk and epsA genes was 71% and 38%, respectively. Coexistence of ptk with epsA genes was observed in 29% of the isolates. The prevalence of the ptk and the epsA genes among of isolates differs noticeably in different clonal types.

Iranian journal of public health

ABSTRACT

Avicenna Journal of Clinical Microbiology and Infection, 2015

Jundishapur Journal of Microbiology, 2015

Background: Multidrug resistant strains of Acinetobacter baumannii (MDR-AB) have emerged as alarm... more Background: Multidrug resistant strains of Acinetobacter baumannii (MDR-AB) have emerged as alarming nosocomial pathogens among patients with burning. Objectives: The current study aimed to determine the susceptibility of A. baumannii species, carbapenems resistance patterns, and their association with IS Aba 1 and IS Aba 4 elements upstream of the bla OXA -like genes, and the distribution of international clone (IC) of A. baumannii isolates among patients with burning in Tehran, Iran. Materials and Methods: In the current study, 62 A. baumannii species isolates from patients with burning in Tehran, Iran, in 2012 were evaluated for the antimicrobial susceptibility, genetic relationships, ICs, carbapenemase encoding genes, and insertion elements IS Aba upstream of bla OXA -like genes. Results: The highest rates of susceptibility were observed with colistin (88.7%) and tigecycline (82.2%). The extensively drug-resistance and pan drug-resistance were observed in 37.1% and 8.1% of the isolates, respectively. About 98.3% of 17 genotypes categorized into three distinct clusters. Thirty-six of the 62 isolates (58%) belonged to the IC II lineage. The most prevalent acquired OXA-type carbapenemase was bla OXA-23 -like (62.9%). IS Aba 1 and IS Aba 4 were detected upstream of bla OXA-23 -like genes in 45.1% and 12.9% of isolates, respectively. In 32.2% of all isolates, IS Aba 1 laid upstream of bla OXA-51 -like genes. The PCR results were negative for carbapenemase genes of Ambler class A and B, except bla VIM-2 . (1.6%). Conclusions: It was the first study that attempted to detect the insertion elements IS Aba and IC lineages in MDR-AB species isolated from patients with burning in Iran.

Iranian journal of microbiology, 2016

Klebsiella pneumoniae, one of the important causes of nosocomial infections, is the most common e... more Klebsiella pneumoniae, one of the important causes of nosocomial infections, is the most common extended spectrum β-lactamases (ESBLs) producing organism. ESBLs are defined as the enzymes capable of hydrolyzing oxyimino-cephalosporins, monobactams and carbapenems. The aims of this study were to identify ESBL-producing K. pneumoniae isolates and detect their antibiotic susceptibility pattern. This cross-sectional study was conducted from December 2012 to May 2013 in teaching hospitals in Shiraz. Clinical specimens from the urine, sputum, wound, blood, throat, and body fluids were isolated and identified as K. pneumoniae. Antibacterial susceptibility testing was performed for 14 antibiotics using disk diffusion method according to CLSI guidelines. Isolates showing resistant to at least one of the β-lactam antibiotics were then evaluated for production of β-lactamase enzymes using E-test ESBL and combined disk Method. Also, MICs for ceftazidime and imipenem were determined using E-test...