Antibacterial susceptibility patterns of porphyromonas gingivalis isolated from chronic periodontitis patients

Objectives: To test the antimicrobial sensitivity of Porphyromonas gingivalis to a panel of eight orally administrable antibiotics in chronic periodontal diseases and to evaluate factors associated with periodontitis in adult patients. Study Design: A total of fifty strains of P. gingivalis were isolated from one hundred and twenty adult patients with chronic perio-dontitis. Identification of bacteria was carried out by anaerobic culture and biochemical tests. Selected colonies of P. gingivalis were used to evaluate the antibacterial activities of penicillin, metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin, doxy-cycline, ciprofloxacin and azithromycin. Results: Most of the patients were female, age ranging between 40 to 50 years. Majority of the patients frequently had scaling and depths of periodontal pockets in infected teeth were 5-8 mm and most of them had hemorrhage during sampling. Susceptibility testing revealed a sensitivity of 100% of P. gingivalis to azithromycin, doxycycline and amoxicillin/clavulanic acid but lower susceptibilities were found for the rest of antibiotic agents evaluated. Conclusions: Frequent scaling in women aged between 40-50 years had positive correlation with chronic periodontitis. The application of antibiotics in conjuction with mechanical debridation, may reflect in the level of resistance of P. gingivalis in patients with chronic periodontal infections. This could suggest periodical antibiotic susceptibility testing is necessary to determine the efficacy of antimicrobial agents if the perfect curing of chronic periodontal diseases after mechanical debridation is meant. Further clinical studies are required to confirm the in vitro results. The only limitation in this study was identification of bacteria to species rather than subspecies level. © Medicina Oral S.L

Prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus and its antibiotic susceptibility pattern in healthcare workers at Namazi Hospital, Shiraz, Iran

SummaryObjectiveThe aim of this study was to determine the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers (HCWs) at Namazi Hospital, Shiraz, Iran.MethodsThis cross-sectional study was conducted from July to November 2006. Nasal swabs were taken from 600 randomly selected HCWs. The isolates were identified as S. aureus based on morphology, Gram stain, catalase test, coagulase test, and mannitol salt agar fermentation. To analyze sensitivity patterns of MRSA strains more precisely, minimum inhibitory concentrations (MICs) of antibiotics were determined by the E-test method. All methicillin-resistant isolates were examined for the existence of the mecA gene by total DNA extraction and PCR.ResultsThe prevalence of nasal carriage of methicillin-sensitive S. aureus (MSSA) was 25.7% and of MRSA was 5.3%, with the highest nasal carriage of MRSA in surgical wards and the emergency department. There was no significant difference between the sexes (p=0.247), age (p=0.817), and years of healthcare service (p=0.15) with regard to the nasal carriage of MRSA and MSSA. In the univariate analysis, a statistically significant difference was only found for occupation (p=0.032) between the carriage of MSSA and MRSA. In the multivariate analysis, the occupation ‘nurse’ was independently associated with MRSA carriage (p=0.012, odds ratio 3.6, 95% confidence interval 1.3–9.7). The highest resistance rate for both gentamicin and clindamycin (69%) was noted among the MRSA strains. None of the MRSA strains were resistant to mupirocin, linezolid, fusidic acid, or vancomycin. The existence of the mecA gene in all 32 methicillin-resistant isolates was observed by PCR.ConclusionsThis study revealed the prevalence of nasal carriage of S. aureus strains among HCWs to be lower than that found in other studies from Iran. The antibiotic susceptibility patterns also differed, perhaps as a result of the excessive use of antibiotics at our hospital. Only the occupation of nurse was an independent risk factor for MRSA carriage

Active immunization using exotoxin A confers protection against Pseudomonas aeruginosa infection in a mouse burn model

<p>Abstract</p> <p>Background</p> <p><it>Pseudomonas aeruginosa </it>is an important cause of nosocomial infection and may lead to septicemia and death. We evaluated the immunogenicity of semi-purified exotoxin A from the bacterium in a mouse burn model.</p> <p>Methods</p> <p>The toxoid was prepared from exotoxin A taken from toxigenic strains of <it>P. aeruginosa </it>(PA 103). 50 mice were immunized with the toxoid, burned with hot metal and infected with 1 × 10⁸CFU of toxigenic strains of <it>P. aeruginosa </it>(experimental group); 25 non-immunized mice were also burned and infected (control group). The mortality rate and presence of any exotoxin and <it>P. aeruginosa </it>in the sera, liver and spleen were determined.</p> <p>Results</p> <p>In the experimental group, 2 mice died before the burns were administered and were excluded from the study. The remainder (48 mice) were challenged with a lethal dose of <it>P. aeruginosa </it>and followed for 70 days. 3 of these mice died. Neither <it>P. aeruginosa </it>nor exotoxin A was not detected in the liver, spleen or sera of the surviving mice. The protective efficacy of toxoid vaccination was therefore 93.8%. In the control group, all mice died from bacteremia and septicemia, most (80%) within 6 days, and <it>P. aeruginosa </it>and exotoxin A were isolated from sera, spleen and liver.</p> <p>Conclusion</p> <p>Active immunization of mice using a semi-purified exotoxin A derived from <it>P. aeruginosa </it>was 93.8% effective at protecting mice from subsequent <it>P. aeruginosa </it>infections in a mouse burn model.</p

Advanced therapeutic dressings for effective wound healing

Advanced therapeutic dressings that take active part in wound healing to achieve rapid and complete healing of chronic wounds is of current research interest. There is a desire for novel strategies to achieve expeditious wound healing due to the enormous financial burden worldwide. This paper reviews the current state of wound healing and wound management products, with emphasis on the demand for more advanced forms of wound therapy and some of the current challenges and driving forces behind this demand. The paper reviews information mainly from peer reviewed literature and other publicly available sources such as the FDA. A major focus is the treatment of chronic wounds including amputations, diabetic and leg ulcers, pressure sores, surgical and traumatic wounds (e.g. accidents and burns) where patient immunity is low and the risk of infections and complications are high. The main dressings include medicated moist dressings, tissue engineered substitutes, biomaterials based biological dressings, biological and naturally derived dressings, medicated sutures and various combinations of the above classes. Finally, the review briefly discusses possible prospects of advanced wound healing including some of the emerging approaches such as hyperbaric oxygen, negative pressure wound therapy and laser wound healing, in routine clinical care

Molecular Typing of Pseudomonas aeruginosa Strains Isolated from Burn Patients in South of Iran

Background: Pseudomonas aeruginosa is one of the main etiological agents in burn infections which could be life threatening for the infected patients. The aim of the present study was to identify and track source of infections using two molecular typing methods. Materials and Methods: Seventy-four strains of P. aeruginosa were isolated from burn patients and hospital environment in Ghotbadden Burn Hospital, Shiraz, Iran. Isolates were typed by arbitrary primed-polymerase chain reaction (AP-PCR) and plasmid profiling. Similarity and clustering of the strains was assessed using NTSYS-PC software and photo Capt Mw program. Results: Thirty eight plasmid profiles were obtained and classified them into: 2, 3and 5 clusters, based on 50%, 64.7% and 67.5% similarity on the plotted dendrogram, respectively. Drawn dendrogarm categorized AP-PCR products to 47 different types. Conclusion: Based on these results, a limited number of P. aeruginosa types are predominant in the hospitals which infect the burn patients. To control of the infections in patients with antibiotics, resistant isolates, strong disinfection of patients&rsquo; bathroom after scrubbing of patients wounds, should be implemented

Immunomodulating Effect of Cyclophosphamide on the Mice Infected with Candida albicans

Background & Objectives: Cyclophosphamide is an alkylating agent that stops the replication of DNA, which is used to treat various types of cancer and some autoimmune disorders. This study was aimed at then evaluating the immunomodulating effect of cyclophosphamide (Cy) on the immune system of vaccinated and non-vaccinated mice.Materials & Methods: The  study was performed on three groups of mice consisting of vaccinated, non-vaccinated and control groups. Vaccination was carried out by three separated courses of C. albicans injection intraperitoneally.  Then,  the  vaccinated group  received Cy  on  day  zero  and  were  challenged  with  lethal  doses of  C. albicans  on  days  zero, one, 3, 6 and 12 post-Cy injection. Non-vaccinated group received Cy on day zero and similar to vaccinated ones were challenged with lethal doses of the organism. The control groups received  just  Cy  on  day  zero  and  were  sacrificed  on days  post-Cy injection. Then, the hemogram and the spleen and the renal tissues were studied microscopically and macroscopically.Results: In the vaccinated group, an increase in survival time, the number of polymorphonuclear and the significant hyperplasia in the white pulp on days 6 and 12 post-Cy injection were noticed. In non-vaccinated ones, these factors had significant decrease on days 1 and 3. Conclusion: It is concluded that the hyperplasia in the white pulp of spleen and an increasing in peripheral polymorphonuclear due to the selective effects of Cy could effectively protect the animal against C. albicans infection

The Immunomodulatory Effect of Recombinant Exotoxin A of Pseudomonas Aeruginosa on Dendritic Cells Extracted from Mice Spleen

Background & Objective: Dendritic cell (DC) is as a key cell in activation of immune response against microbes and disease. Therefore, the effect of recombinant exotoxin A of Pseudomonas aeruginosa on the maturity and the activation of DCs was evaluated in this study. Materials & Methods: Recombinant exotoxin A was produced from Pseudomonas aeruginosa DNA. MTT assay was used to evaluate the cytotoxicity of this protein on DCs. The expression of co-stimulatory molecules CD40, CD86, and MHCΠ was evaluated by flow cytometry. Moreover, the effect of this antigen (Ag) on T-cell proliferation was evaluated using Mixed Lymphocyte Reaction (MLR) assay and the secretion of IL-4 and IFN- γ. Secretion of IL-12 by DCs was measured with Enzyme-Linked Immunosorbent Assay (ELISA) method. The data were collected and analyzed with one way ANOVA test. Results: Recombinant exotoxin A had no effect on DCs viability. In addition, expression of CD40, CD86, and MHCΠ did not change significantly compared to the negative control cells. Moreover, T-cells proliferation was decreased significantly at the concentration of 0.1µg/ml of this Ag. The secretion of IL-12 was increased by DCs, in contrast the secretion of IL-4 and IFN-γ in MLR supernatant did not decrease significantly. Conclusion: Exotoxin A decreases the proliferation of T-cells and also leads to a change in the pattern of cytokine secretion of immune cells

Characterization of Shigella Strains in Iran by Plasmid Profile Analysis and PCR Amplification of ipa Genes

To characterize Shigella clinical strains, we studied 82 Shigella strains recovered from 719 stool samples of patients with bloody diarrhea in Shiraz, Iran, over the period from April to October 2003. Serological assay classified the Shigella isolates as follows: 61 (74.39%) Shigella sonnei isolates, 16 (19.51%) Shigella flexneri isolates, 3 (3.65%) Shigella boydii isolates, and 2 (2.43%) Shigella dysenteriae isolates. In an antibiogram test, all Shigella strains were susceptible to ceftazidime, ciprofloxacin, and ceftriaxone. They showed high degrees of sensitivity to nalidixic acid, gentamicin, cephalothin, and amikacin. Approximately 90.24% of the Shigella isolates were resistant to co-trimoxazole. The plasmid profile patterns of all strains were determined by a modified alkaline lysis method. The average number of plasmid bands for each strain was 9.5. By plasmid profile analysis we identified 56 genotypes among all isolates and 42, 14, 3, and 2 genotypes among the S. sonnei, S. flexneri, S. boydii, and S. dysenteriae strains, respectively. PCR assays showed that all isolates were positive for two virulence genes, ipaBCD and ipaH. In conclusion, these data mandate local monitoring of drug resistance and its consideration in the empirical therapy of Shigella infections. These results also demonstrate that plasmid profile analysis is more reliable than antibiotic susceptibility pattern analysis for the identification of Shigella epidemic strains isolated in Iran