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  Background and Objectives: Pseudomonas aeruginosa is a nosocomial pathogen that presents high antibiotic resistance.There are phenotyping and genotyping methods for epidemiologic study of Pseudomonas aeruginosa such as antibiotic resistance pattern and plasmid profile analysis. Plasmid analysis provides useful information concerning the source of the strains and number of clones present in the epidemies. Thus, this study was conducted to evaluate antibiotic and plasmid profiles of P. aeruginosa strains isolated from in-patients of the Sina Medical Centre of Tabriz to clarify epidemyological correlation among isolated strains.

  Methods: During 13 months, 135 strains of P. aeruginosa were isolated from different infections in hospitalized patients at Sina Medical Center of Tabriz. Antibiotic susceptibility tests were performed using disc agar diffusion test. For plasmid DNA extraction and detection of open circular bands from supercoiled ones, modified alkaline lysis procedure and two dimensional electrophoresis were used, respectively. Enzymatic digestion of plasmids was carried out by EcoRI and HincII restriction enzymes.

  Results: Resistance rates of strains against antibacterial agents were recorded as: Aztreonam (77%), colistin (74%), ceftazidime (69%), pipracillin (67%), ofloxacin (62%), tobramycin (56%), carbenicillin (54%), gentamicin (51%), ciprofloxacin (22%), amikacin (15%), polymixin B (13%) and imipenem (2%). Plasmid profiles of our test strains revealed that only 67 strains harbored plasmid(s). Number of isolated plasmids ranged 1-6 in each strain with molecular mass of 0.5kb-21kb. When the isolated plasmids were digested using restriction endonuclease enzymes (EcoRI and HincII), in 32% of them similar digestion profiles were obtained by EcoRI indicating a unique source for them.

  Conclusion : Our findings suggest high antibiotic resistance and plasmid presence in P. aeruginosa strains isolated from different infections, and there were remarkable similarities among isolated plasmids. Since our test strains had been isolated from various wards in a short period of time, the results raise the possibility of unique source for some strains or high prevalence of genetic exchange among P. aeruginosa strains.

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  Background & objectives: Nosocomial infections increase patient’s mortality and are considered as a health problem. The aim of this study was to assess the risk factors for nosocomial infections and antimicrobial resistance pattern of isolated bacteria in NICU and PICU, in Bahrami and Children’s Medical Center hospitals, Tehran .

  Methods: In a prospective cross-sectional study from October 2008 to September 2009, risk factors and etiology of nosocomial infections were evaluated in all patients who showed infectious signs upon 48h admission. Infectious agents were diagnosed by the standard microbiological tests and antibiotic sensitivity of isolates was determined using dick diffusion method. The data for location of the hospital, admission history, presence of immunodeficiency, fever and using venous and urine catheters, suction, venous injection as well as cerebral shunt and surgery have been collected by a questionnaire and analyzed, statistically .

  Results: About 9.3% (70 individuals) of cases encountered with nosocomial infections. From whom, 24.3% were infected by Pseudomonas aeroginosa and 18.6% and 3.14% by Klebsiella pneumonia and Enterobacter spp, respectively. The location of the hospital, using of suction and surgery were the most common risk factors related to nosocomial infections (p<0.05).

  Conclusion: Our findings showed that the hospital location, suction and surgery were the most common risk factors and Pseudomonas aeroginosa, Klebsiella pneumonia and Enterobacter spp were the common infectious threats. So, we need to design the special program to improve nosocomial infection control in hospitals .

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  Background & Objectives: Nosocomial infections occur following admission of patients in the hospitals and usually are accompanied by significant mortalities. This study was conducted to determine the frequency of nosocomial infections and the causatives in Ardabil Bu Ali hospital during 2010.

  Methods: This study was a cross-sectional study which has been done on collection of information through practical examinations, laboratory tests and files of nosocomillay infected patients in Ardabil Bu Ali hospital during 2010. Data were analyzed by SPSS.

  Results: From a total of 3254 patients, 42 (1.3%) had got nosocomial infections. Of these infected patients 47.6% was males and 52.4% was females. Infection was more frequent in patients with ages between 1 month to1 year old (45.2%). Sepsis (33.3%), pneumonia and blood stream infections (23.8%) and urinary tract infection (19%) were the most frequent infections. The mean length of hospital stay was 26.86 days. Klebsiella pneumoniae was the most common pathogen reported (23.8%). Infection was more common in NICU (38.1%).

  Conclusion: In this study, the frequency of nosocomial infection was lower than other studies. Distribution of infection differed with age, ward and length of stay in the hospital.

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  Background & objectives: Wound infection is a predominant cause of death in burned patients who are clearly at increased risk of nosocomial infections. Pseudomonas aeruginosa is the most common cause of burn infections and is difficult to treat because of having high level of resistance to antibiotics. The aim of this study was to perform isolation, identification and determination of antibiotics resistance pattern of P. aeruginosa strains isolated from wounds of hospitalized burn patient.

  Methods: Biochemical and molecular tests were used for identification of the P. aeruginosa and antibacterial susceptibility test was performed using disk diffusion (Kirby- Bauer) methods. Then, the minimum inhibitory concentration (MIC) was performed for four representatives of different groups of antibiotics.

  Results: Among 94 evaluated strains of P. aeruginosa, 83 isolates (88.3%) were multi drugs resistant. Based on Kirby-Bauer method, the most resistance was seen to cefepime (89.5 %) and among the antibiotics studied to determine the MIC, the most resistance was observed to ciprofloxacin (89 %).

Conclusion: These results indicate high range of resistance to different antibiotics among strains of P. aeruginosa isolated from burn wounds of patients. So, the fast and accurate measurement and evaluation of antibiotic resistance for appropriate antibiotic therapy of burned patients is imperative.

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Background & objectives: Enterococcus spp. are predominant in the faecal microflora which enter the environment directly or through wastewater. These bacteria play an important role in the development of nosocomial infections due to their ability to acquire resistance genes and their transmission to other bacteria, particularly Staphylococcus aureus. The aim of this study was to identify the prevalence of vancomycin-resistant enterococci (VRE) and to detect van A, van B and van C1/C2 genes in VRE strain isolated from environmental samples of the in southern Fars province.
Methods: This cross-sectional study was carried out on 155 Enterococcus spp isolates collected from environmental samples (hospital wastewaters and surface waters) in different areas of Larestan and Jahrom cities. Isolates were identified and confirmed as Enterococcus spp. using the membrane filtration method, selective growth on Kenner Fecal Streptococcus Agar (KF) medium and biochemical tests. The disk diffusion test and Macro Broth dilution method based on CLSI guidelines were used to determine antimicrobial susceptibility against conventional antibiotics and vancomycin and to measure the minimum inhibitory concentration (MIC), respectively. Finally, the presence of van A, van B and van C1/C2 genes in VRE strains was determined by multiplex PCR technique.
Results: Out of all of Enterococcus spp. isolates, 41 cases (26.45%) were belonged to E.faecalis, 6 cases (3.87%) to E.faecium and 108 cases (69.68%) to non-faecalis and non-faecium. In total, 46 isolates (29.67%) were resistant to vancomycin and 4 isolates showed MIC ≥128 μg/ml. Resistant to all types of antibiotics was observed in 4 isolates (8.70%). Further, 2 isolates (50%) had vanA gene and 2 isolates (50%) had vanB gene, but vanC1/C2 genes were detected in none of them.
Conclusion: The results indicated that the VRE strains are widespread in the studied area, therefore there is an urgent need for prudent use of vancomycin and implementation of control measures to prevent the environmental spread of VRE strains.

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