Iranian Journal of Microbiology
Volume:11 Issue: 4, Aug 2019

Cutaneous candidiasis is a multipicture fungal infection caused by members of the genus Candida which is considered as a public health problem all over the world with urgency of effective treatment and control. This study was performed to analyze the clinical epidemiology and molecular aspects of cutaneous candidiasis in Tehran-Iran in relation to antifungal susceptibility and virulence factors of etiologic Candida species.

Candida species were isolated from skin (27.3%) and nail scrapings (72.7%) of suspected patients and identified by ITS sequencing. Phylogeny of the isolates was evaluated using multilocus sequence typing (MLST) and antifungal susceptibility and virulence factors of the isolates were determined in relation to clinical presentation.

Candida albicans was the most prevalent species (39.8%), followed by C. parapsilosis (32.9%), C. orthopsilosis (10.4%), C. tropicalis (7.9%), C. glabrata and C. guilliermondii, each (4.5%). Molecular typing of 35 C. albicans isolates by MLST revealed 28 novel sequence types with 11 singletons with 80.0% new diploid sequence types (DSTs). Majority of the isolates were susceptible to amphotericin B (91.5%), followed by posaconazole (90.3%), fluconazole (84.3%), itraconazole (74.1%), caspofungin (53.6%), and voriconazole (26.8%). Biofilm formation, yeast-to-hyphae transformation and phospholipase activity were reported species-dependent.

Our results demonstrated clinical epidemiology of various Candida species from cutaneous candidiasis distributed in new molecular types with increasing importance of drug resistant of non-albicans Candida species. Our results showed that drug susceptibility and genetic variability of Candida species may be attributed to their clinical features and source of isolation.

The aim of this study was to determine the prevalence of neonatal sepsis with a focus on antibiotic resistance and the frequency of the blaCTX-M-15 and blaOXA-48 genes in Gram-negative isolates.

A total of 108 Umbilical Cord Blood (UCB) and 153 peripheral blood samples were cultured via BACTEC from May 2017 to June 2018. The bacterial isolates were identified using phenotypic and genotypic analyses. The antibiotic susceptibility profile of the isolates was determined by disk diffusion. PCR was used to determine the frequency of β-lactamase genes.

Among the 153 infants, 21 (13.7%) proved positive for sepsis. Escherichia coli, Staphylococcus epidermidis and Klebsiella pneumoniae were the most frequent isolates in the peripheral blood cultures. E. coli and Stenotrophomonas maltophilia were isolated from two UCB cultures. The highest resistance among the Gram-positive strains was to cefixime, ceftriaxone, cefotaxime and clindamycin. In the Gram-negative bacteria the highest rates of resistance were to ampicillin (91.7%). The frequency of blaOXA-48 and blaCTX-M-15 genes was 25% and 50%, respectively.

The high antibiotic resistance among the isolates reveals the importance of monitoring antibiotic consumption and improving control standards in the health care system, especially in neonatal wards.

Klebsiella pneumoniae isolates that produce K. pneumoniae carbapenemase (KPC) have become a grave concern for the treatment of infections. KPC-producing strains are not only able to hydrolyze carbapenems but are also resistant to a variety of β-lactam and non-β-lactam antibiotics. The present study evaluated the prevalence of blaKPC in K. pneumoniae infections and determined the antimicrobial susceptibility of the isolates.

The K. pneumoniae isolates were identified by biochemical tests and confirmed by genotyping. The modified Hodge test (MHT) was performed to detect carbapenemases, and antimicrobial susceptibility was determined for all isolates by the disc diffusion method. Also, for MHT-positive isolates, supposed to carbapenemases isolates, broth microdilution method was used to measure the minimum inhibitory concentrations (MICs) of meropenem and colistin.

The blaKPC genotypic evaluation revealed that only 5 of 96 isolates carried blaKPC genes. Antimicrobial pattern showed that isolates carrying blaKPC were resistant to cefepime, ticarcillin/tazobactam, and aztreonam discs. Also, results of broth microdilution method showed that KPC-producing K. pneumoniae was resistant to meropenem and colistin, according to the CLSI and EUCAST.

In this study nearly half the isolates showed carbapenemase activity as shown by MHT results, but only few of them were carrying blaKPC. Thus blaKPC gene is not the main cause of resistance spread to carbapenems in Isfahan, Iran.

The aim of this study was to compare the systemic humoral immune responses, including IgE, IgA, IgG and IgM levels in Balb/c mice administered a probiotic, LPS derived from Escherichia coli (E. coli), and probiotic-LPS derived from E. coli.

Thirty-two male Balb/c mice, 10-12 weeks of age with body weight ranging from 30-40 g were randomly divided into four experimental groups (n=8). The treatment regimens were as follows: Group 1, mice did not receive LPS or probiotic (control group); Group 2, mice received only LPS on the first day; Group 3, mice received probiotic for 7 days; Group 4, mice received LPS on the first day, and then continued, with probiotic for 7 days. The mice were observed for 8 days, and then, euthanized the next day (day 9). The serum was collected, and the levels of IgE, IgA, IgG and IgM were measured using ELISA.

The humoral immune response was higher in the presence of a probiotic compared to that in the control; IgE (9.02 ± 0.58 units/ml, p=0.000), IgA (3.26 ± 0.99 units/ml, p=0.316), IgG (7.29 ± 0.24 units/ml, p=0.000), and IgM (4.01 ± 2.98 units/ml, p=0.505). When administered with LPS E. coli along with probiotic, the humoral immune response was the highest; IgE (10.68 ± 1.63 units/ml, p=0.000), IgA (8.34 ± 1.47 units/ml, p=0.000), IgG (9.96 ± 0.98 units/ml, p=0.000), and IgM (4.31 ± 1.05 units/ml, p=0.319) compared to the control group.

Probiotic-LPS derived from E. coli treatment induced a higher humoral immune response (highest IgE, IgA, IgG and IgM levels) compared to treatment with probiotic only.

Probiotics and prebiotics are known to regulate immune responses. A synbiotic is a product that combines probiotics and prebiotics in a single dosage form. In this study, we attempt to present the effects of a multispecies synbiotic on intestinal mucosa immune responses after exposure to Escherichia coli O55:B5 lipopolysaccharide (LPS).

Totally 21 male Balb/c mice were randomly classified into two groups. The K-I group received LPS and a synbiotic, and the K-II group received LPS alone. The synbiotic was administered for 21 consecutive days, whereas LPS was administered once on the 15th day. Specifically, a synbiotic containing 1 × 109 colony forming units (CFUs) of the probiotic combination of Lactobacillus acidophilus PXN 35, L. casei subsp. casei PXN 37, L. rhamnosus PXN 54, L. bulgaricus PXN 39, Bifidobacterium breve PXN 25, B. infantis PXN 27 and Streptococcus thermophilus PXN 66 and the prebiotic fructo-oligosaccharide was administered through an orogastric tube. Immunohistochemistry was performed to measure immunoglobulin A (IgA) levels for humoral immune responses and CD4+ and CD8+ levels for cellular immune responses.

An independent-samples t-test revealed significant increases of the numbers of IgA- (p = 0.027) and CD4-expressing cells (p = 0.009) but not the number of CD8-expressing cells in the K-I group compared with those in the K-II group.

The multispecies synbiotic had immunoregulatory effects on IgA and CD4 expression in LPS-exposed mice.

Human epithelial cells have been widely used to study the interaction between intestinal cells and pathogens, in vitro. In this study, the effect of probiotic bacteria Bacillus coagulans and its supernatant on the growth inhibition, cytotoxicity and induction of apoptosis caused by Salmonella Typhimurium and its adhesion to HT-29 cells were investigated.

B. coagulans supernatant was used to obtain the minimum inhibitory concentration. To evaluate the cytotoxicity and percent of apoptotic cells, B. coagulans and its supernatant (2, 4, 6 and 8% concentrations) with S. Typhimurium was added to HT-29 cells. The MTT assay was used in order to evaluate the cytotoxicity. Percent of apoptotic cells was reported using a fluorescence staining method. Additionally, the adhesion of S. Typhimurium to HT-29 cells was investigated. The effect of B. coagulans on the level of adhesion was also studied.

The most inhibitory effect was shown at the concentration of 80000 µg/ml supernatant of B. coagulans (54.77% ± 1.43). The simultaneous culture of S. Typhimurium with B. coagulans had the lowest amount of cytotoxicity and induced apoptosis among the all co-culture groups of S. Typhimurium with B. coagulans or its supernatant. The determined cytotoxicity and induced apoptosis were 26.06 % ± 3.79 and 17.63 % ± 2.14 respectively. In the adhesion test, it was observed that B. coagulans can significantly prevent adhesion of S. Typhimurium to HT-29 cell.

B. coagulans can reduce the adhesion, cytotoxicity and induction of apoptosis caused by S. Typhimurium in HT-29 cells in vitro.

Self-adhesive resin cements release fluoride and have cytotoxic and preventive monomers against the bacteria in their composition. They have acidic property before their complete setting too. The antibacterial activity of three different self-adhesive resin cements against Streptococcus mutans at different time intervals was investigated in this study.

The modified direct contact test was used to evaluate the antibacterial effect of Max-Cem, G-Cem and Bis-Cem on S. mutans after aging the samples in phosphate-buffered saline solution for one hour, 24 hours and 1 week. Data were analyzed using one-way ANOVA, repeated measurement ANOVA and Tukey HSD tests (P<0.05).

The differences in the mean bacterial counts between all the study groups and between the study groups and the corresponding control groups were significant at 1-hour and 24-hour intervals (P<0.001). At 1-week, only the differences between Bis-Cem and G-Cem, between Max-Cem and Bis-Cem, and between Bis-Cem and the corresponding control group were significant (P<0.001). There were significant differences between G-Cem and Max-Cem at all the time intervals (P<0.001). In addition, with the use of Bis-Cem there were significant differences between 1-hour and 1-week (P=0.01) and 24-hour and 1-week (P<0.001).

All the cements exhibited antibacterial activity after 1 hour and 24 hours. However, after 1 week, only Bis-Cem retained its antibacterial activity.

Serralysin is an extracellular metalloprotease from Serratia marcescens which has been the subject of extensive biological investigations. The goal of this study was to extract and purify serralysin from S. marcescens and to investigate its cytotoxic activity on the colorectal cancer cell line.

The presence of the serralysin gene was confirmed using PCR. The supernatant of bacterial culture was collected and precipitated using ammonium sulfate. The precipitated protein was dialyzed and subjected to ion exchange chromatography for further purification. Casein assay and skim milk assay was used to confirm the enzymatic activity. SDS-PAGE was used to visualize the presence of serralysin. Metalloprotease inhibition activity was performed using 50 mM EDTA. Cytotoxic activity of serralysin was assessed on MTT assay.

The PCR product corresponding to serralysin was estimated to be approximately 1500 bp. A transparent zone around the bacterial colonies on skim milk agar and casein digestion confirmed the proteolytic activity of serralysin. A 52 kDa band in SDS-PAGE corresponding to serralysin was observed before and after purification processes. MTT assay showed IC50 values 24.78 μg/ml and 19.16 μg/ml after 24 h and 48 h exposure of Caco-2 cells to serralysin, respectively.

Our results showed that native serralysin has anticancer potential and may be a candidate for further pharmaceutical research and development. Further in vivo and in vitro mechanistic studies are suggested to confirm the biological activities.

Fibrinolytic drugs are commonly used for fibrin clot lysis but due to their inappropriate side effects, as well as their high costs, using fibrinolytic enzymes has been paid attention. Bacterial sources of this enzyme are a good alternative for this purpose. The aim was fibrinolysin production through screening of fibrinolysin producing bacteria from environmental samples.

Bacterial isolation was performed from different environmental samples and was screened based on sheep blood clot digestion and culture on plasma plate. The most potent isolate was optimized for different growth parameters including temperature, pH and fibrinolysin production at optimum growth conditions. The stability of produced enzyme at various temperatures and pH and treatment with MgSO4, NiSO4, SDS and EDTA was then investigated. Finally this isolate was identified based on the 16S rRNA sequencing.

As a result, from 79 different isolates, the most potent fibrinolysin producer was identified as Alcaligenes faecalis strain 26. This isolate produced 12 mm halo zone on plasma plate. Its optimum growth temperature and pH was 43°C and 7, respectively. The produced enzyme had the best stability at pH 7 and was also active up to 60°C. The fibrinolytic activity of this isolate was reduced following treatment with MgSO4, NiSO4 and also with protease inhibitors, such as SDS and EDTA.

Based on the obtained results it can be suggested that Alcaligenes faecalis strain 26 has appropriate efficiency for fibrinolysin production that can be used in food industry and medicine.

Microbial superantigens have been reported in the blood and synovial fluid of rheumatoid arthritis patients, raising the question of whether the presence of these superantigens could provoke the induction of inflammatory biomarkers expression or not. The purpose of this study was to examine the Staphylococcus aureus superantigen C on CD18 expression.

The superantigen C was purified by ultrafiltration. Immunoblotting was performed using a specific antibody. Also, 50 micrograms of superantigens (toxin) were injected intraperitoneally and intra-articularly into separate rat groups. Blood was collected and RNA extracted. Then, the cDNA was synthesized. The expression of CD18 marker was evaluated using RT-real-time PCR, and the results were descriptively analyzed.

The results of this study revealed that 50 μg of toxin, injected intra-articularly and intraperitoneally, showed the surplus expression of the marker CD18 in the blood of rats after 20 days. By this method, the expression of the marker CD18 was significantly different between rats that received the superantigen intra-articularly and intraperitoneally (2.10; 2.3 and 3.3 folds) and the controls (P≤ 0.05).

The results indicated that the presence of Staphylococcal of superantigen C in the body of rats has enhanced the expression of the CD18 inflammatory marker more than 3 times. This valuable finding is an introduction to further research and could provide new methods to prevent and control inflammatory diseases, including rheumatoid arthritis.

Invasive aspergillosis of the paranasal sinuses is a rare and often misdiagnosed disease. This study reported a case of maxillary aspergillosis with a complete headache and eye pain after tooth extraction with a large abscess in the relative jaw. Tenderness in the right temporal, lower jaw numbness and right eye proptosis was found. Histopathological examination was the suggestion of maxillary sinusitis with a fungal ball of aspergillus.