Acinetobacter baumannii strains play an important role in the development of urinary tract infection, pneumonia, septicemia, wound infection and meningitis. They are also resistant to antimicrobi-al agents and are one of the important pathogen in nosocomial infections (1-5). . . .

Salmonella enteric serovar Typhi (S. typhi) and paratyphi (S. paratyphi) bacteria exclusively found in humans, cause typhoid fever, an acute, and possibly deadly systemic infection. Typhoid fever is caused by a species of rod-shaped, Gram-negative Enterobacteriaceae called S. typhi. The present study aimed to examine the intI gene and investigate the possible relation between this gene and multi-drug resistance in S. typhi. A total of 30 blood samples were obtained from patients who were suspicious of typhoid fever using the direct strategy of inoculation. Each specimen was injected into a culture of a selective medium, such as XLD and SS agar, and then incubated at 37°, C for 24 h. The genomic DNA was extracted through a boiling process. Tris-EDTA was used to suspend bacterial colonies cultured on MacConkey agar plates. The suspension of bacterial colonies was centrifuged for 5 min at 8000×g and for 20 min at-20°, C which lyses the organisms and extracts the DNA from the buffer. The supernatant is then transferred to a fresh Eppendorf tube. Gel electrophoresis was carried out utilizing a UV transilluminator. The intI gene for S. typhi was found using a PCR test. The antibiotic sensitivity testing showed that the S. typhi isolates were classed as multi-resistant. These results were confirmed using the polymerase chain reaction (PCR) technique using intI gene where twenty specimens isolated from typhoid patients were positive for S. typhi.

Background and Aim: In recent years, Multidrug resistance has been increasing among Klebsiella isolates. The aim of this study was to survey existence of Integrons and its relation with antibiotic resistance among clinical isolates of Klebsiella. Materials and Methods: From Jun 2015 to May 2016, 129 Klebsiella isolates collected from Karaj hospitals and laboratories. Statistical population included 80. 6% female and 19. 4% male. Antimicrobial susceptibility was performed using Kirby-Bauer disk diffusion and ESBLs producer were screened. Integrons were detected using PCR. Ethical Considerations: This study with research ethics code IR. IAU. K. REC. 1396. 16 has been approved by research ethics committee at Islamic Azad University of Karaj, Iran. Findings: The highest and lowest percentage of sensivity were found to ofloxacin (89. 1%) and amoxcicillin (6. 2%), respectively. 82. 9% of isolates were resistant to more than two antibiotics from different classes. Among 129 isolates, 19. 3% of the isolates harbour Integrons. Frequencies of MDR among Integron-positive isolates were 100%. Also, 71. 3% and 28. 7% of isolates were ESBLs positive and negative respectively. Conclusion: Results showed Integron elements were prevalent among MDR isolates. Integron-associated resistance genes can be served as reservoirs of multi drug resistance within clinical isolates and presence of Integron can be used as a marker to identify MDR isolates. Prevalence of ESBLs among clinical isolates of Klebsiella showed that antibiotics like ampicillin or amoxicillinclavulanic acid are not effecvtive anymore in treatment of UTIs.

Background: The aim of the current study was to determine class 2 Integron associated antibiotic resistance in Escherichia coli strains isolated from four animal sources.Methods: E. coli strains were isolated from different animal sources including human, hen, cow and sheep. Bacterial strains were isolated and identified by standard microbiological and biochemical tests. The antimicrobial susceptibility testing was performed according to Kirby Baur assay using 11 antibiotic discs including Amikacin, Co-trimoxazole, Tobramycin, Stereptomycin, Piperacillin, Ampicillin, Cefazolin, Nalidixic acid, Gentamicin, Kanamycin, and Neomycin. Total genomic and plasmid DNAs were extracted using Accu- PrepÒ Genomic DNA Extraction Kit. To detect the class 2 Integron, a newly designed int 2 specific primer was used for amplification of integrase gene by PCR. The PCR amplicons were visualized after electrophoresis and staining with SYBR green.Results: Eighty E. coli strains were isolated and included in this study. Antibiotic susceptibility testing showed that 59% of the isolates were MDR while 10% harbored the int2gene. Following statistical analysis, chi–square test and p value determination, we found significant association between the presence of class 2 Integron and resistance to Streptomycin, Sulfamethoxazole and Kanamycin. Conclusion: Our findings showed that class 2 Integrons have significant distribution among Escherichia coli strains in different animal sources. Specific care and control on antibiotical resistance including screening of Integrons are important strategies to prevent the spread of antibiotic resistance in E.coli.

Background and objectives: The present study was conducted to detect class 1 Integrons and evaluate antibiotic susceptibility patterns among clinical isolates of P. aeruginosa. Methods: Sixty clinical samples from blood, tracheal wounds, burns and urinary tract infections were collected from three general hospitals in Tehran, Iran. Culture of specimens was performed on common bacteriological culture media. Bacteria were identified based on mobility, pigment production, growth at 42 oC, and oxidase and catalase tests. Overall, 21 P. aeruginosa strains were isolated. Antimicrobial susceptibility of was evaluated via the disk diffusion method (Kirby-Bauer) according to the CLSI guidelines. Presence of the intI1, sul1, aadA2 and aadB gene cassettes was investigated using PCR. The collected data were analyzed using SPSS software (version 21). Results: The most effective antimicrobial agents against P. aeruginosa isolates were tetracycline and gentamicin. All P. aeruginosa isolates were multidrug resistant. Moreover, the intI1, sul1, aadA2 and aadB genes were found in 90. 5%, 90. 5%, 47. 6% and 19% of the P. aeruginosa isolates, respectively. Conclusion: The results indicate that the presence of aadB, aadA2 and sul1 gene cassetes may play an important role in the dissemination of antimicrobial resistance determinants.

Background: Acinetobacte is the leading cause of pneumonia and sepsis in the ICU ward. Accordingly, in the present study, the antibiotic susceptibility pattern, presence, and dissemination of diff, erent classes of Integrons and fl, uoroquinolone resistance genes were investigated among A. baumannii isolates. Methods: In this descriptive, cross-sectional study, during a period of 24 months (2018-2020), 100 isolates of A. baumannii were isolated from diff, erent clinical specimens of patients admitted to the two teaching hospital in Ardabil province in the northwest of Iran. Kirby-Bauer disk diff, usion, PCR, and sequencing methods were used for antimicrobial susceptibility testing and gene and mutation verifi, cation. Results: The resistance rates to all tested antibiotics were found to be between 78% and 100%. No isolate was resistant to polymyxin B. Multidrug-resistant (MDR) rate among tested clinical isolates was about 99%. The prevalence of class 1, 2, and 3 Integrons was found to be 70%, 21%, and 0%, respectively. The aadA1 cassette gene was detected in all class 1 Integron-carrying strains. Conclusions: High-level antibiotic resistance and a high prevalence of Integrons were observed among these clinical isolates. Our fi, ndings highlighted the need for continuous monitoring of resistant isolates.

Aim: The purpose of this study was to determine the antibiotic susceptibility pattern and distribution of Integron in H. pylori isolates collected from patients referred to private health care centers in Tehran, Iran. Background: Antibiotic resistance is the main reason for failure of Helicobacter pylori therapy. Integrons as genetic reservoirs play main roles in the dissemination of antimicrobial resistance gene. Methods: During a 12-month cross-sectional study period, 65 H. pylori isolates were recovered from 124 biopsy specimens. Isolates were subjected to susceptibility testing using by Epsilometer test according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guideline. PCR was used to detect different types of Integrons. Results: Antimicrobial susceptibility testing revealed that 73. 8% of isolates were resistant to metronidazole, 43. 1% to clarithromycin, 29. 2% to tetracycline, 27. 7% to amoxicillin, 23. 1% to rifampicin and 13. 4% to levofloxacin. Frequency of multidrug resistance among H. pylori isolates was 26. 1%. The most predominant resistance profiles among our isolates were included resistance to clarithromycin and metronidazole (20%). Class 1 and 2 Integrons were detected in 8 (12. 3%) and 15 (23. 1%) of the isolates, respectively. Conclusions: The high prevalence of multidrug resistance and frequency of class 2 Integron in this survey can be a warning for clinicians. Continuous surveillance is necessary for the development of new treatment protocols to prevent the treatment failures and also further spread of resistant isolates.