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Antibiotic resistance is an important problem in antibiotic treatment of infections, particularly in hospitals. Tomatidine is a plant secondary metabolite with antimicrobial and antifungal effects. This study examined the possible synergistic effect tomatidine with several antibiotics against standard and clinical strains of Staphylococcus aureus , Enterococcus faecalis , Pseudomonas aeruginosa and Escherichia coli . After determining the minimum inhibitory concentrations (MICs) of antibiotics and tomatidine against the bacterial isolates using broth microdilution method, the synergistic effect between tomatidine and antibiotics was evaluated by checkerboard method and calculation of FIC indices. Tomatidine alone did not show any antimicrobial effect. However, it had synergistic effect with gentamicin and cefepime against standard and clinical isolates of S. aureus and P. aeruginosa , respectively. It also had synergistic effect with ampicillin and ciprofloxacin only against standard strains of E. faecalis and P. aeruginosa , respectively. In conclusion, tomatidine could be considered as a potential antibiotic potentiator for gentamicin, cefepime and ciprofloxacin, and ampicillin against Staphylococcus aureus , Pseudomonas aeruginosa , and Enterococcus faecalis infections, respectively. However, the toxicological and pharmacological properties of tomatidine for use as a therapeutic agent remain to be determined.

Background: During the past several years, nontuberculous mycobacteria (NTM) have been reported as some of the most important agents of infection in immunocompromised patients., Objectives: The aim of this study was to evaluate the ciprofloxacin susceptibility of clinical and environmental NTM species isolated from Isfahan province, Iran, using the agar dilution method, and to perform an analysis of gyrA gene-related ciprofloxacin resistance., Materials and Methods: A total of 41 clinical and environmental isolates of NTM were identified by conventional and multiplex PCR techniques. The isolates were separated out of water, blood, abscess, and bronchial samples. The susceptibility of the isolates to 1 µg/mL, 2 µg/mL and 4 µg/mL of ciprofloxacin concentrations was determined by the agar dilution method according to CLSI guidelines. A 120-bp area of the gyrA gene was amplified, and PCR-SSCP templates were defined using polyacrylamide gel electrophoresis. The 120-bp of gyrA amplicons with different PCR-SSCP patterns were sequenced., Results: The frequency of the identified isolates was as follows: Mycobacterium fortuitum, 27 cases; M. gordonae, 10 cases; M. smegmatis, one case; M. conceptionense, one case; and M. abscessus, two cases. All isolates except for M. abscessus were sensitive to all three concentrations of ciprofloxacin. The PCR-SSCP pattern of the gyrA gene of resistant M. abscessus isolates showed four different bands. The gyrA sequencing of resistant M. abscessus isolates showed 12 alterations in nucleotides compared to the M. abscessus ATCC 19977 resistant strain; however, the amino acid sequences were similar., Conclusions: This study demonstrated the specificity and sensitivity of the PCR-SSCP method for finding mutations in the gyrA gene. Due to the sensitivity of most isolates to ciprofloxacin, this antibiotic should be considered an appropriate drug for the treatment of related diseases.

Background: Helicobacter pylori infection is highly prevalent in the developing countries. It causes gastritis, peptic ulcer disease, and gastrocarcinoma. Treatment with drugs and antibiotics is problematic due to the following reasons: cost, resistance to antibiotics, prolonged treatment and using multiple drugs. Catalase is highly conserved among the Helicobacter species and is important to the survival of the organism. It is expressed in high amounts and is exposed to the surface of this bacterium; therefore it represents a suitable candidate vaccine antigen., Objectives: A suitable approach in H. pylori vaccinology is the administration of epitope based vaccines. Therefore the responses of T-cells (IFN-γ and IL-4 production) against the catalase of H. pylori were determined. Then the quality of the immune responses against intact catalase and three epitopes of catalase were compared., Materials and Methods: In this study, a composition of three epitopes of the H. pylori catalase was selected based on Propred software. The effect of catalase epitopes on T-cells were assayed and immune responses identified., Results: The results of IFN-γ, IL-4 production against antigens, epitopes, and recombinant catalase by T-cells were compared for better understanding of epitope efficiency., Conclusions: The current research demonstrated that epitope sequence stimulates cellular immune responses effectively. In addition, increased safety and potency as well as a reduction in time and cost were advantages of this method. Authors are going to use this sequence as a suitable vaccine candidate for further research on animal models and humans in future.

Background: Pseudomonas aeruginosa might be converted to coccoid bacteria under antibiotic stress. Bacterial conversion would increase resistance to antibiotics due to changes in cell wall crosslink or decreased metabolic activity. Morphology of P. aeruginosa under stress conditions (presence of antibiotics) can be changed to elongated bacilli, U shape and finally coccoid bacteria. Results of several researches showed that coccoid bacteria are one of the most important aspects of drug resistance. It would be the major reason for treatment failure., Objectives: The aim of this study was to determine in vitro morphological and bactericidal effects of amikacin, meropenem and imipenem on P. aeruginosa isolated from clinical specimens., Materials and Methods: Eight P. aeruginosa isolates obtained from clinical samples of burned patients and standard strain ATCC 27853 were used in this study. Isolates were identified by biochemical tests and confirmed by PCR method using ITS specific primer. Minimum inhibitory concentrations (MICs) of three antibiotics were determined by E-test method. Bacteria were exposed to antibiotics at different concentrations. Bacterial morphology in different days was examined by specific microscope and viability of isolates was examined by flow cytometry., Results: All used antibiotics at sub MIC concentration had capability to induce coccoid bacteria. The highest rate of induced coccoid bacteria was 98.2% after 8 days, with contribution of imipenem and meropenem at 2 μg/mL concentration. Amikacin at 4 μg/mL concentration induced lower rate of coccoid bacteria (55.05%). Amikacin had a strong bactericidal effect on coccoid bacteria at 8 μg/mL concentration. Imipenem and meropenem showed very weak bactericidal effect on coccoid bacteria., Conclusions: Induction of coccoid form of P. aeruginosa may be one of the important reasons for antibiotic treatment failure; therefore, prescribed dose of antibiotics should be carefully managed to prevent increasing antibiotic resistance and coccoid bacteria induction.

Background: Pseudomonas aeruginosa is a well-known opportunistic pathogen, which affects hospitalized patients in different wards due to its natural resistance to drugs., Objectives: The purpose of the current study was to determine the antibiotic susceptibility profiles and genetic relatedness in P. aeruginosa isolated from patients admitted to a referral hospital in Isfahan, Iran., Materials and Methods: Out of 150 analyzed samples, 54 P. aeruginosa isolates were recovered and were subjected to antibiotic resistance patterns and genetic diversity determination by Kirby-Bauer's disk diffusion method and RAPD-PCR, respectively., Results: The highest percentage of resistance was observed against ceftazidime and imipenem with 30 (55.6%) isolates; meanwhile all isolates were sensitive to polymyxin B. Twenty-eight (51.8%) isolates revealed resistance to all applied antibiotics. RAPD-PCR (Random Amplified Polymorphic DNA- Polymerase Chain Reaction) results showed 54 unique genotypes, which were divided into 39 clusters., Conclusions: Although different source of P. aeruginosa may involve in patient colonization, genetically related strains were isolated from different wards and or the same ward of the hospital. Our results pointed to the restriction of currently used antibiotics in studied hospital. We hope that our results cast light on the control and transmission of the infection in the investigated hospital.

Background: Helicobacter pylori (H. pylori) is a spiral Gram negative bacteria that can transform to the coccoid form in adverse conditions., Objectives: The aim of this study was to determine the in vitro morphological and bactericidal effects of metronidazole, amoxicillin and clarithromycin on H. pylori., Materials and Methods: The standard strain 26695 of H. pylori was cultured on Brucella agar (BA) and the minimum inhibitory concentrations (MICs) of three antibiotics were determined by E-test method. The bacteria were exposed to antibiotics at 1/2 MIC, MIC and 2X MIC concentrations in Brucella broth (BB). Induced coccoid forms were confirmed by Gram staining and light microscopy. The viability of cells as well as the susceptibility of viable coccoids to antibiotics were examined using the flow cytometry method., Results: All of the three antibiotics at sub-MIC induced coccoid forms. The highest rates of coccoids (> 90%) were induced at 0.008 μg/mL concentration (1/2 MIC) of amoxicillin, 72 hours postexposure. Metronidazole and clarithromycin with 1/2 MIC (0.5 and 0.125 µg/mL respectively) induced lower rates of coccoid forms (60% and 40% respectively). Potent bactericidal effects on coccoids were observed with Metronidazole at 2X MIC and clarithromycin at MIC (0.25 µg/mL) (80 - 90%). Amoxicillin with MIC and 2X MIC had no bactericidal effect on coccoid forms., Conclusions: Despite the good in vitro bactericidal effect of amoxicillin on spiral forms of H. pylori, this antibiotic has little effect on induced coccoids that may develop after the inappropriate in vivo antibacterial treatment. Hence, for successful therapy, it is essential not only to eradicate the spiral forms, but to eliminate the viable coccoids.