Genomic analysis of Mycobacterium bovis and other members of the Mycobacterium tuberculosis complex by isoenzyme analysis and pulsed-field gel electrophoresis.

Initially, multilocus enzyme electrophoresis was used to examine genetic relationships among 63 isolates of Mycobacterium bovis and 13 other members of the M. tuberculosis complex. The isolates were divided into five electrophoretic types, with a mean genetic diversity of 0.1. The strains were genetically homogenous, indicating that members of the complex were closely related. This supported the suggestion that they should be considered as subspecies of a single species. Pulsed-field gel electrophoresis (PFGE) was then used to differentiate these isolates, as well as 59 additional isolates of M. bovis from different parts of the world. PFGE differentiated these strains into 63 patterns (53 patterns for M. bovis). Isolates of M. bovis from Western Australia (n = 46) were more homogenous than isolates from other regions. Eight strains were identified in that state, and one predominantly bovine strain was isolated from two human beings and a feral pig. Although M. bovis isolates from different parts of the world had distinct DNA patterns, some were very similar. PFGE is a highly discriminatory technique for epidemiological studies of bovine tuberculosis. For example, it allowed differentiation between isolates of M. bovis cultured from animals in separate outbreaks of tuberculosis, it suggested the transmission of infection between certain properties, and it demonstrated the existence of multiple infections with different strains at certain farms.     

Drug resistance pattern of Mycobacterium tuberculosis isolates from patients of five provinces of Iran

Objective:To determine the patterns of resistance to first line anti-tuberculosis(TB)drugs among a collection of Mycobacterium tuberculosis(MTB)isolates from 5 provinces of Iran.Methods:A total of the 6 426 clinical specimens from patients suspected of active TB were collected from March 2010 to June 2012.All specimens were subjected for microscopy and culture tests in the TB centers of studies provinces.Drug susceptibility testing to the first line anti-TB drugs for culture positive MTB was performed on Lwenstein-Jensen(LJ)medium using proportion method.Results:Of 6 426 clinical specimens,261 were culture positive for mycobacteria,of which 252 were MTB and 9 were MOTT(mycobacteria other than tuberculosis).Of 252 MTB isolates.211(83.7%)were pan-susceptible and 41(16.3%)were resistant to at least one drug.Resistance was most common to streptomycin.30 isolates(12.0%),followed by isoniuzid,20isolates(8.0%),rifampin,15 isolates(6.0%)and ethambutol,14 isolates(5.5%).Sixteen(6.3%)MTB isolates were MDR.A clear evidence of heterogeneity amongst the 5 provinces in the proportions with resistance to one or more drugs was observed[χ~2=12.209(4 degrees of freedom),P values=0.015 9].Conclusions:The prevalence of drug resistance in this study area underscoring the need for further enforcement of TB control strategies in the Iran.Drug susceptibility testing for all TB cases to provide optimal treatment,establishing advanced diagnostic facilities for rapid detection of MDR-TB and continuous monitoring of drug resistance are recommended for prevention and control of drug-resistant TB.     

Isolation and Identification of E. cowanii from Powdered Infant Formula in NICU and Determination of Antimicrobial Susceptibility of Isolates

Objective: Enterobacter cowanii is a genus of common gram-negative, facultatively anaerobic, rod-shaped, non-spore-forming bacterium of the Enterobacteriaceae family. This organism can be potentially a powdered infant milk formula-borne opportunistic pathogen. The aim of this study was to isolate and identify E. cowanii from consumed powdered infant formula milk (PIF) in intensive care units (NICU) and to determine antimicrobial susceptibility patterns of this bacterium. Methods: E. cowanii was isolated according to FDA method in 125 samples of PIF milk purchased from drug stores between Jun 2011 and March 2012. For final confirmation, biochemical tests embedded in API-20E system were used. The drug susceptibility test was performed using the disc diffusion method according to CLSI recommendations. Findings : Out of the 125 PIF samples investigated, 4 (3.2%) samples were positive for E. cowanii. All four isolates from PIF samples were uniformly susceptible to imipenem, meropenem, ceftazidime, ciprofloxacin, and colistin. Fifty percent of isolates were resistant to ampicillin, amoxicillin, and cotrimoxazole Conclusion: Analysis of the results indicated that complementary studies are necessary to clarify the possible role of E. cowanii as a food contaminant, in common NICU infections and high risk groups including persons with underlying disease and immunocompromised individuals.Key Words: Powdered Infant Formula Milk; Neonatal Intensive Care Unit; E. Cowanii; Antimicrobial Susceptibility     

Serovar determination,drug resistance patterns and plasmid profiles of Pseudomonas aeruginosa isolated from burn patients at two hospitals of Tehran (IRAN)

The serovars and drug susceptibility patterns of 265 isolates of Pseudomonas aeruginosa cultured from burn patients during 2001-2002 at Motahari and Tohid Hospital were determined. Distribution of serovars was different at two hospitals. Most of the isolates at Tohid Hospital belonged to serovar 0:1, but 21 and 13% of them were untypeable or polyagglutinable, respectively. Serovar 0:11 was the most prevalent serovar at Motahari Hospital. All the strains were multi resistant to tetracyclin, carbenicillin, amikacin, ceftazidime, sulfamethoxazol, ciprofloxacin, tobramycin, kanamycin, cefotaxime and gentamicin. Further analysis of the strains by plasmid profiling demonstrated that 95% of the isolates carried two megaplasmids. However, there was not any correlation between the serotyping and presence of plasmids. Changes in the drug susceptibility patterns and beta-lactamase production of some cured derivatives were observed after the strains lost their plasmids. The emergence of multi-drug resistant strains of P. aeruginosa is a serious concern in burn patients who are hospitalized in Tehran.     

Detection of VEB-1, OXA-10 and PER-1 genotypes in extended-spectrum β-lactamase-producing Pseudomonas aeruginosa strains isolated from burn patients

Resistance of Pseudomonas aeruginosa strains to the broad-spectrum cephalosporins may be mediated by the extended-spectrum β-lactamases (ESBLs). These enzymes are encoded by different genes located on either chromosomes or plasmids. This study aimed to investigate the prevalence of ESBLs and antimicrobial susceptibilities of P. aeruginosa isolated from burn patients in Tehran, Iran. Antimicrobial susceptibility of 170 isolates to cefpodoxime, aztreonam, ciprofloxacin, ofloxacin, ceftazidime, cefepime, imipenem, meropenem, cefotaxime, levofloxacin, piperacillin–tazobactam and ceftriaxone was determined by disc agar diffusion test. Polymerase chain reaction (PCR) amplification of the genes encoding OXA-10, PER-1 and VEB-1 was also performed. All isolates (100%) were resistant to ceftazidime, cefotaxime, cefepime and aztreonam. Imipenem and meropenem were the most effective anti-pseudomonal agents. The results revealed that 148 (87.05%) of the isolates were multidrug resistant and 67 (39.41%) of the isolates were ESBL positive. Fifty (74.62%), 33 (49.25%) and 21 (31.34%) strains among 67 ESBL-producing strains amplified bla_OXA-10, bla_PER-1 and bla_VEB-1 respectively.     

Molecular characterization of CTX-Mβ-lactamases among Klebsiella pneumoniae isolated from patients at Tehran hospitals

Purpose: Plasmid-encoded CTX-M-group of extended-spectrum β-lactamases (ESBLs) represent a significant and rapidly emerging problem in most part of the world. The aim of the present study was to describe the prevalence of CTX-M producing Klebsiella pneumoniae at Tehran hospitals. Materials and Methods: Clinical isolates of K. pneumoniae (n=250) were collected from 10 hospitals of Tehran. Susceptibility to antimicrobial agents, MIC of cefotaxime and ESBLs production of collected isolates were detected. All ESBL-producing isolates were screened for bla_CTX-M genes using PCR and DNA sequencing. Molecular typing of bla_CTX-M harboring isolates was performed by Pulsed–field gel electrophoresis assay. Results: Of 250 K. pneumoniae clinical isolates, 102 isolates revealed ESBLs – phenotype. PCR assay and sequencing detected bla_CTX-M genes in 71.5% (n= 73) of ESBL-producing isolates. The prevalence of CTX-M -I and CTX-M-III clusters among these isolates was 35.61% (n=26) and 21.9 % (n=16) respectively. Coexistence of CTX-M -I and CTX-M-III clusters was found among 42.5% (n= 31) of isolates. Of 102 isolates that were positive in the phenotypic confirmatory test (PCT), 29 isolates (28.4%) did not produce any amplicons in PCR for bla_CTX-M gene. The results of PCR for CTX-M -II and CTX-M-IV clusters were also negative. Analysis of the 31 CTX-M producing K. pneumoniae isolates by PFGE typing showed 26 distinct patterns. Conclusions: The bla_CTX-M genes are widespread among Iranian isolates of K. pneumoniae. PFGE demonstrated the high diversity of K. pneumoniae harboring bla_CTX-M in our study.     

Isolation and drug-resistant patterns of Campylobacter strains cultured from diarrheic children in Tehran

To detect campylobacteriosis and determine the drug susceptibility of causative organisms, we acquired 500 diarrheic samples in Cary-Blair transfer medium from two pediatric hospitals in Tehran between October 2004 and October 2005. The samples were also enriched in Preston broth (with supplements) and defibrinated sheep blood (7%). They were plated from both media on Brucella agar containing antibiotics and blood. Isolates were identified through biochemical tests and by the polymerase chain reaction method. Drug susceptibility testing was performed using the disk diffusion method. In total, 40 Campylobacter strains were isolated (8%). C. jejuni was the dominant species (85.8%) followed by C. coli (14.2%). The rates of resistance to antimicrobial agents were as follows: ciprofloxacin (61.7%), ceftazidime (47%), carbenicillin (35%), tetracycline (20.5%), cefotaxime (14.7%), ampicillin (11.7%), neomycin erythromycin and chloramphenicol (2.9%), gentamicin, streptomycin, imipenem and colistin (0.0%). Campylobacter is an important cause of diarrhea among Iranian children. The detection of Campylobacter increases by 25% if samples are treated in enrichment broth prior to plating. The high rate of resistance to ciprofloxacin is alarming, and further investigation into the possible reasons for this is imperative.     

Association between diabetic retinopathy and polymorphisms of cytokine genes: a systematic review and meta-analysis

International Ophthalmology - Diabetic retinopathy (DR) is a medical condition caused by damage to the blood vessels of retina tissue due to diabetes mellitus. DR leads to injury in neural and...     

Multidrug-resistant strains of Mycobacterium tuberculosis isolated from patients in Tehran belong to a genetically distinct cluster

Restriction fragment length polymorphism (RFLP) analysis was used to study the molecular epidemiology of tuberculosis (TB) in certain areas of Tehran. 120 isolates of Mycobacterium tuberculosis, including drug-resistant strains (n = 23), were analysed using polymorphic GC-rich sequence (PGRS) and IS6110 probes. There was considerable diversity among the strains cultured from patients from certain areas. The results of RFLP showed that multidrug resistant (MDR) isolates of M. tuberculosis in Tehran belong to a group of strains with low copies of IS6110 and PGRS. The degree of clustering was higher for the drug-resistant strains than for the susceptible ones (65% vs 20%). Based on the demographic data and results of RFLP, it appears that recent transmissions of TB from old patients have occurred in Tehran. However, drug-resistant TB in the city is mainly caused by strains that look different from those cultured from such patients. The majority of MDR isolates (85%) in this study contained a low copy number of IS6110 and PGRS in RFLP, and were mostly recovered from immigrants and refugees.     

Laparoscopic ureteroureterostomy for the management of obstructive uropathy caused by congenital ureteric entrapment in the iliac bone

A rare case of congenital entrapment of the left ureter in an iliac bone canal causing left side hydroureteronephrosis is reported. The patient represented a case of congenital ureteral entrapment in a reversed C-shaped iliac bone canal that was missed before his laparoscopy. The ureter also had a retro-iliac course. The patient was successfully managed by laparoscopic ureteroureterostomy. Interestingly, in our experience, laparoscopy provided a minimally invasive milieu for both diagnosis and correction of this rare cause of obstructive uropathy.