Evaluation of the Effect of Lactobacillus acidophilus ATCC 4356 Bacteriocin against Staphylococcus aureus.

Background: Lactobacillus acidophilus is lactic acid bacteria that produce bacteriocins. Bacteriocins are antimicrobial peptides or proteins that exhibit activity against closely related bacteria. The aim of this study was to determine the effect of L. acidophilus ATCC 4356 bacteriocin against Staphylococcus aureus. Material and Methods. We used four different phenotypic methods for antimicrobial activities against two standard strains: methicillin-resistant S. aureus (MRSA) ATCC 33591 and methicillin-susceptible S. aureus (MSSA) ATCC 25923. The methods were (1) agar well diffusion, (2) overlay soft agar, (3) paper disk, and (4) modification of punch hole. The ammonium sulfate method was used to concentrate crude bacteriocin, and ultrafiltration and dialysis tubes were used to remove ammonium sulfate from the bacteriocins. Each method was repeated in triplicate. Result: L. acidophilus ATCC 4356 showed antimicrobial activity against both MRSA and MSSA standard strains only by the overlay soft agar method and not by the agar well diffusion, punch hole modification, and paper disk methods. No antimicrobial effects were observed in crude bacteriocins concentrated. Conclusion: The growth inhibition of S. aureus in overlay soft agar method may be due to the production of bacteriocin-like substances. The overlay soft agar method is a qualitative test, so there is a need for further study to optimize the conditions for the production of bacteriocin-like substances in the culture supernatant and precise comparison between the inhibitory activity and pheromone secretion of different strains.

Molecular Characterization of Streptococcus Pneumoniae from Patients Diagnosed with Pneumonia: Recommendation for Vaccination Program.

Background: Infections caused by Streptococcus pneumoniae (S. pneumoniae) have remained a significant public health concern worldwide. In developed countries, the highest prevalence of S. pneumonia has been reported among the elderly. The aim of this study was to evaluate the coverage of genotypes in the 13-valent pneumococcal conjugate vaccine (PCV-13) in the Iranian elderly population. Methods: A total of 41 isolates of S. pneumoniae were collected in the current retrospective cross-sectional study. The samples comprised 33 inpatients hospitalized for pneumococcal pneumonia and 8 outpatients. Multiplex polymerase chain reaction assay was performed to categorize the bacteria isolated into specific genotypes. Statistical analyses were performed using SPSS software, and the chi-square test was used to assess the statistical significance in percentages. Results: A total of 68 genotypes were identified in this study, in which 39 isolates (57.3%) were associated with invasive infections. The most common genotypes were 6A/B [8 (19.5%)], 1 [7 (17.5%)], 14 [5 (12.2%)], and 19A [4 (9.75%)], respectively. The coverage rates of PCV-7, PCV-10, and PCV-13 vaccines were 51.17%, 70.7%, and 99.9%, respectively. According to our results, the pneumococcal coverage rate of PCV-7, PCV-10, and PCV-13 vaccine types is estimated to be 51.2%, 70.7%, and 99.9%, respectively. Furthermore, the trend of pneumococcal serotypes included in the PCV-13 was steadily increasing during the study period. Conclusion: It can be concluded that the most circulating pneumococcal serotypes were in accordance with specific serotypes included in the PCV-13 vaccine types. Therefore, including PCV-13 vaccines in immunization programs against pneumococcus in the elderly can effectively reduce the rate of infections.

Detection of Toxoplasma gondii bradyzoite genes in the peripheral blood mononuclear cells among patients with toxoplasmic chorioretinitis.

BACKGROUND: Toxoplasmic chorioretinitis may occur as a result of acquired toxoplasmosis or reactivated congenital toxoplasmosis. In this study, Toxoplasma gondii bradyzoite genes along with the B1 gene were evaluated to detect T. gondii DNA in serum and peripheral blood mononuclear cells (PBMCs) of patients with toxoplasmic chorioretinitis. METHODS: Blood samples were collected from 10 patients (7 cases of active chorioretinal lesions and 3 cases of old chorioretinal scars). The genomic DNA was extracted from the patients' serum and PBMCs and a polymerase chain reaction (PCR) assay was performed using bradyzoite genes along with B1. The subjects were also evaluated in terms of the T. gondii antibodies. RESULTS: The PCR results were positive in four of seven patients (57.1%) with active ocular toxoplasmosis lesions. In three patients (42.8%), the PCR results were positive for MAG-1 and SAG-4 and in one patient (14.3%) the PCR results were only positive for the B1 gene. The PCR results were positive only in the PBMCs, whereas they were negative in the serum samples. Two patients with positive PCR results showed high Toxoplasma immunoglobulin G (IgG) antibody titres. However, none of the patients showed positive Toxoplasma IgM antibodies. CONCLUSIONS: The PBMCs are suitable for evaluating toxoplasmic chorioretinitis. The present results showed that PCR with bradyzoite genes is useful in the diagnosis of toxoplasmic chorioretinitis in PBMCs.

Comparison of the effects of Lactobacillus plantarum versus imipenem on infected burn wound healing.

Background: Infection of burn wounds is one of the most important problems in the world. Lactobacillus plantarum is known for burn wound healing because of the immunomodulatory and anti-microbial roles. This study was performed to compare the effects of L. plantarum and imipenem - alone and in combination - on infected burn wound healing. Methods: Burn wounds were experimentally induced on 50 rats in three test groups (germ and supernatant of L. plantarum ) and two control groups (n=10 each) and were inoculated with Pseudomonas aeruginosa. During a 14-day period, wounds in all groups were daily treated topically. The data were analyzed using one-way analysis of variance followed by Tukey-Kramer and LSD. A p-value of < 0.05 was considered as statistically significant. Results: The mean size of the wound on day 14 after the treatment in the probiotic group was significantly lower than the control and the supernatant treated groups (p<0.05). The percentage of wound healing was significantly higher in the probiotic pellet treated group compared to the imipenem and the supernatant groups (by Anova test: 69.58%, p=0.022). The mean leukocyte count in the probiotic pellet group (12110) and supernatant group (13650) was significantly higher than the imipenem group (7670) (p=0.002 and 0.001, respectively). Wound cultures revealed that the percentage of cases where the pathogens had no growth was significantly different among the comparison groups. In all three test groups, P. aeruginosa was completely eliminated in comparison to the positive control group (p<0.05). Conclusion: The results of our study showed that L. plantarum and its by-products promote wound healing and can be used as an alternative to antibiotics to treat ulcer infections caused by resistant bacteria.

The Prevalence of S. aureus Skin and Soft Tissue Infections in Patients with Pemphigus.

Pemphigus vulgaris are autoimmune blistering diseases that may result in significant morbidity and death. Immunosuppressive therapy of pemphigus vulgaris would predispose the patients to infections. The aim of this study was to assess the prevalence of S. aureus infection and PVL gene in patients with pemphigus admitted to dermatology clinic. Materials and Methods. This descriptive study was conducted on 196 pemphigus vulgaris patients (119 males, 77 females) admitted to dermatology clinic between 2014 and 2015. In this study, the diagnosis of pemphigus vulgaris was made by histology, immunofluorescence pattern of perilesional skin, and indirect immunofluorescence testing of serum. Data were collected through a questionnaire. Results. 59.1% of pemphigus vulgaris patients had S. aureus infection. 49 out of 116 were methicillin-resistant. PVL gene was detected in 25 out of 116 S. aureus positive patients. Conclusion. This is the first report of S. aureus infection in pemphigus patients in Iran. More than forty percent of isolates were methicillin-resistant S. aureus. PVL gene carried by methicillin-resistant S. aureus was high in this study.