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Abstract Background and objectives: "The comb antibiotic sensitivity test" is a quick, reliable and cost effective method to determine the susceptibility of bacteria to different antibiotics. The purpose of this study is to design a plate that is easy and quick to use, and enable to be interpreted easily without the need for measurement of the margins with a ruler. Material and Methods: First, Clinical and Laboratory Standards Institute data about the maximum growth inhibitory haloes formed with antibiotics and various micro-organisms were statistically examined and determined that the most (99.7%) zone of inhibition growth is formed in the range of 42 mm. Accordingly, the obtained number (42 mm) and conventional plate size (100 mm) used for testing sensitivity were punched into Solid works software which was used to determine the best place of strip and shoulder plates. After that the efficacy this media were examined by determination of MIC Staphylococcus aureus and Klebsiella pneumonia, non-graded and graded plate shoulders were searched and compared. Results: Has been placed two combs MIC in a plate in this method and didn’t create growth inhibitory haloes interferences. Obtained MIC for Nitrofurantoin( 10 µg/ml) , Amikacin(0.5 µg/ml), Gentamicin(1 µg/ml) , and Amoxicillin (0.5 µg/ml) against S.aureus , MIC Nalidicsic Acid, Amikcin, Gentamicin and Nitrofurantoin against K.pneumonia was 0.1, 0.5, 0.5 and 10 µg/ml ,respectively. Conclusion:The comparison between this new innovative method and standard methods (Clinical Laboratory Standards Institute - CLSI) shows that there a marked reduction in the interference of antibiotic therapy and will also reduce time of interpretation. Key words: Plate, Antibiogram Comb, MIC, Antibiotics, Drug resistance.

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Abstract Background and objectives: Infection stones are the directly due to persistent or recurrent infection with Urease producing bacteria. they may be exacerbated by urinary obstruction or stasis. Also, some drug components like ciprofloxacin can be the cause of stone formation. We aimed at studing antibiotic resistance of bacteria isolated form kidney stones and Urinary tract infection(UtI). Material and Methods: This descriptive study, during 2008-2010,we obtained kidney stones and urine of 45 patients under gone nephrolithotomy in shahid Beheshti hospital of Babol, Iran. The stones were transferred to microbiology Lab in a strile Condition, after grinding, cultured on Blood Agar and Eosin-Methylene Blue(EMB) media. In Addilion, urin Samples were cultured on the for mentioned media. The Positive cultures were qualitatively evaluated and then, antibiogram was done by using Kirby Bauer method. Results: The resulte show that 10 kidney stone specimens and 8 urine samples were infected by bacteria, mostly by E.coli. In one stone sample and two urine samples, we can isolate more than one bacteria. The bacteria isolated in the stone and urine samples of six patients was the same. We could find two cases of staphylococcus inurine and one in stone culture. The bacteria isolated from stone are resistance to oflaxacin(80%) , which is higher than that to the other antibiotics. Conclusion: Based on the results, there is no relationship between the kind of kidney stone and type of bacteria. Further study needs to be done to prove this relation. Key words: Kidney stone, Antibiogram, E.coli, Infected stone.

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Abstract Background and Objective: Enterococci are normal flora of human body and considered as the third leading cause of nosocomial infections. The aim of this study was to determine drug resistance of Enterococcus species through biochemical methods. Material and Methods: One hundred twenty-eight of enterococcus suspected samples were isolated from gorgan and gonbad’s hospitals from April to June, 2013. The samples were cultured on blood agar, chrome-agar, EMB agar and some special cultures of isolation of Enterococcus species. Suspension of bacteria was grown in Mueller Hinton agar and the inhibition zone diameter was determined by disk antibiogram. Results: Of 128 samples, 109(85.15%) were enterococci faecalis and 19 (14.85%) Enterococcus Faecium. In all of 128 cases, eight showed resistance to amoxicillin, ten to ampicillin, five to gentamicin, five to ciprofloxacin, six to chloramphenicol, four to cephalexin and one to vancomycin. Conclusion: It seems to be necessary to use drug sensitivity test for having appropriate treatment and preventing from resistance strains. Keywords: Enterococci, Antibiotic Resistance, Antibiogram

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Abstract Background and Objective: The prevalence of different bacterial species and antibiotic resistance varies according to geographical conditions. Hence, we aimed to identify the prevalence of bacterial agents isolated from the urine culture and also investigate the antibiotic susceptibility of bacteria. Material and Methods: This cross-sectional study conducted on 7200 urine samples to identify the bacteria causing infections, using differential tests. The antimicrobial susceptibility was performed via disk diffusion method according to the Clinical and Laboratory Standards Institute (CLSI). Results: The most common bacteria were Escherichia coli (736 61.1%) and Klebsiella pneumonia (128 10.6%) and Enterococcus faecalis, (88 7.3%). The highest antibiotic susceptibility was related to Ciprofloxacin (174 14.45%) and the lowest to Amoxicillin (795 62.02%). Conclusion: Owing to the lowest resistance, it is recommended that Ciprofloxacin be used as the first line of treatment. In addition, Amoxicillin and Ampicillin should be used the least during primary treatment of urinary tract infections. Keywords: Antibiogram, Bacterial Resistance, Urine Culture

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Abstract Background and Objective: Automated Teller Machine (ATMs) is likely to be contaminated with various microorganisms specially pathogen germs. This may be due to their exposure to dust and their vast dermal contact with multiple users. This study investigated the bacterial contamination on the keyboard of ATMs and drug resistance of the bacteria isolated from them. Material and Methods: the keyboards of 50 ATMs in Shahrekord city, Iran, were examined from October 2012 to February 2013. The sterile swab sticks moistened with Triptose soy broth were used for sampling. The bacteriological tests used were culture, biochemical test and agar disk diffusion method for antibiogram. Results: All the samples were found to be contaminated with Coagulase negative staphylococci (57.54%), Bacillus species (21.92%), Staphylococcus aureus (19.18%) and coliform bacteria (1.36%). The resistance of Staphylococcus aureus was 92.8% to penicillin, 85.7% to amoxicilin، 71.4% to ampicillin, 57.1% to nytrofuran, 50% to tetracycline, 42.8% to erythromycin, 42.8% to gentamycin, 14.2 % to ciprofloxacin, 7.1% to trimethoprim and sulfamtuksazul. All species were susceptible to, ofloxacine, chloramphenicol, clindamycin, tobramycin, vancomycin and cefotaxime. Conclusion: given the presence of pathogens on ATMs and their role in transferring the contamination, we recommend considering personal hygiene and periodically disinfecting the keyboards to reduce contamination. Keywords: ATMs, Bacterial Contamination, Antibiogram

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Background and objective: Implementation of standard methods for accurate detection of bacteria, correct antibiotic susceptibility testing and effective treatment of bacterial infections play important roles in development of public health and prevention of drug resistance. This study aimed to detect bacteria using standard methods and compare the results with the results obtained in teaching hospitals’ laboratories.

Methods: Positive culture plates containing bacteria isolated from patients in hospital laboratories in city of Sari were transferred to microbiology laboratory of Faculty of Medicine at Mazandaran University of Medical Sciences, after determining the genus and species of bacteria and antibiotic susceptibility testing of the isolates. The samples were re-examined based on standard protocols, and antibiotic susceptibility testing was done using the Kirby-Bauer method.

Results: Of 101 patients, 20% of bacteria and 22.5% of antibiotic sensitivity results reported by the hospital laboratories were incorrect. There were significant differences between the two study groups in terms of bacterial species detection and sensitivity to some drugs (P<0.05).

Conclusion: In the present study, lack of implementation of internal quality control programs in some hospital laboratories and lack of proper monitoring by regulatory authorities in different departments of the hospital have caused 20% false-detection results in hospital reports. Inconsistency in results of laboratories, false antibiograms and subsequent false laboratory reports cause drug resistance in some patients. This indicates the necessity of continuous training in the field of Microbiology and implementation of standard protocols and methods for detection of bacterial species and antibiotic susceptibility testing.