Jundishapur Journal of Microbiology
Volume:11 Issue: 11, Nov 2018

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading pathogen of serious infectious diseases in intensive care units. Novel antibiotic combination therapies are needed to treat serious infectious diseases caused by MRSA. Our objective was to evaluate the minimum inhibitory concentrations (MICs) of ceftaroline (CPT), telavancin (TLV), daptomycin (DPC), and vancomycin (VA) alone and in vitro synergistic activity of CPT-TLV, CPT-DPC, and CPT-VA combinations against MRSA isolates. Fifty MRSA strains isolated from blood (90%) and tracheal aspirate (10%) of patients in intensive care units (ICUs) between 2013 and 2016 were included in the study. The Epsilometer test was used for determining the synergistic activities of antibiotic combinations. We evaluated the synergistic, additive, indifferent, and antagonist effects of MRSA strains by the fractional inhibitory concentration (FIC) index. Of the 50 MRSA strains tested, 100% were susceptible to TLV, DPC, and VA. CPT was detected as resistant in 3 (6%) of the isolates. CPT-TLV, CPT-DPC, and CPT-VA combinations were found to have synergistic effects in 14%, 38%, 10% and additive effects in 40%, 32%, and 22% of the isolates, respectively. No antagonism was detected in any of the combinations. The combination of CPT with DPC showed the best synergy profile among all antibiotic combinations tested against MRSA isolates obtained from patients in ICUs.

Due to the rapid accumulation of mutations in influenza virus and the unpredictability of new influenza, the current influenza vaccines require an almost yearly reformulation. The extracellular domain of matrix protein 2 (M2e) of influenza A viruses is conserved and is an attractive alternative approach to be used as a vaccine with a broad cross- protection. In this study, a vector containing three repeats of M2e gene of influenza A virus fused with molecular adjuvant of FliC was constructed. In silico analysis of 3M2e.FliC chimeric polypeptide was performed based on 3M2e.FliC sequence, virtual fusion construction translation, linear epitope prediction of 3M2e.FliC, 3M2e.FliC modeling, and validation score consideration through immunoinformatics approaches. Expression of 3M2e.FliC was carried out in two strains of Escherichia coli (BL21 [DE3] and ER2566). The fidelity of expression in both hosts was analyzed through a time course of sampling by SDS-PAGE and confirmed by western blotting. The immunoinformatics results indicated that M2e and FliC epitopes were at the surface of protein, which would be accessible for the immune system. The expression results demonstrated that the 3M2e.FliC construct was expressed well in both strains of E. coli, although the efficiency of expression in ER2566 strain was higher than that of BL21 (DE3) strain. The 3M2e.Flic protein as a recombinant antigen may be considered as a universal influenza vaccine candidate after its evaluation and assessment in animal models.

Candida infections are one of the most important nosocomial infections that have increased by 3.5 to 14 folds over the past decades. Although the sources of infection are human normal flora, hospital environments have an undeniable role. The increased use of antifungals, prolonged prophylaxis, and some organism-associated genetic factors have led to antifungal resistance. The aim of the present prospective study was to identify Candida species from clinical specimens, normal flora, and hospital environments. Furthermore, the susceptibility profile of strains to several antifungals was also evaluated. Two hundred and twenty-one samples (clinical specimens, hospital environments, and personal normal flora) were collected. Samples were inoculated on CHROMagar Candida, incubated at 35°C, and were identified using classical and molecular techniques. Consequently, all recovered isolates were tested against six antifungal drugs, using the microdilution method. Ninety-two Candida strains, belonging to 10 different yeast species, were detected with the most common isolate, Candida albicans (46.74%). Candida albicans made up the majority of species that were obtained from oral samples and non-albicans species with uncommon frequency were obtained from hospital environment samples. Miconazole was a unique antifungal, towards which all strains were sensitive. However, most of the isolates were also sensitive to fluconazole. Although resistance to amphotericin B, terbinafine, fluconazole, caspofungin, and itraconazole was found among C. albicans and non-albicans species, however, miconazole is the most effective antifungals against all strains.

Otitis externa is an inflammatory in external auditory canal, with the presentation of otalgia, otorrhea, and pruritus. Bacteria and fungi are the most causative agents of the disease. Although several antifungal and antibacterial agents are usually used to treat it, combination therapy plays an important role in good treatment efficacy. According to the problems associated with the treatment of mixed otitis externa, the current study aimed at evaluating the efficacy of ceftazidime powder and topical miconazole (as the case group) versus topical miconazole only (as the control group) to treat mixed otitis externa. Seventy-two patients with mixed otitis externa were divided into two groups; the case group was treated with ceftazidime powder and topical miconazole, and the control group was treated only with topical miconazole. Both groups were evaluated after two weeks. The diagnosis of mixed otitis externa was based on signs, symptoms, and the presence of bacterial and fungal elements in direct examination and culture. Swelling, itching, and canal discharge were observed in 67.7%, 64.7%, and 90.3% of the patients, respectively in the case group, and 47.1%, 26.3% and 93.1% of the patients, respectively in the control group. Complete resolution of all clinical signs and symptoms occurred in 23 (67.6%) patients in the case group and 11 (28.9%) patients in the control group (P = 0.001). Staphylococcus epidermidis and Pseudomonas aeruginosa were the most common bacteria, and Aspergillus spp. and Candida spp. were the most common fungi identified in the cultures. According to the complete resolution of clinical signs, the application of ceftazidime powder and topical miconazole was better than topical miconazole to treat mixed otitis externa.

Skin infections with dermatophytes (dermatophytosis) are common human fungal infections, the most common cause of which is Trichophyton rubrum. Antimicrobial peptides (AMPs), which have potential anti-microbial effects, are affected by epidermal growth factor receptor (EGFR) gene. Elevated expression of this gene in skin cells activates AMPs and prevents cloning of dermatophytes in keratinocytes. However, mRNA of EGFR gene is muted with increased expression of microRNAs (miRNAs), in particular miR-212. Therefore, EGFR inhibition may have a negative impact on AMP localization in dermatophyte-infected keratinocytes. This study aimed to determine the changes in the expression of miR-212 and EGFR genes in cutaneous tissues affected by T. rubrum compared to their healthy margins. The number of samples in this study was estimated to be 72. The fungus was cultivated on Sabouraud Dextrose Agar medium. Isolation and optimization of total RNA and synthesis and optimization of cDNA for the EGFR and miR-212 genes were performed. Amplification of these target genes was performed using real-time polymerase chain reaction (RT-PCR). In data aggregation and analysis, changes in expression of the target genes were calculated via 2-ΔΔCt ratio. P value was considered < 0.05. In samples infected with T. rubrum, miR-212 significantly reduced the expression of EGFR gene, and in these samples, the expression of miR-212 gene was eight times higher compared to the expression of the EGFR gene. In control samples, the expression of miR-212 was much lower than that of the EGFR gene. By enhancing the expression of miR-212 in this study, the function of EGFR gene mRNA was turned off, leading to the reduction of AMPs, and in turn, the colonization of T. rubrum and creation of dermatophytosis on the skin.

Leishmaniasis is a protozoan disease ranging from simple to mucocutaneous, diffuse, and visceral lesions. Current chemical medicines, including Glucantime, have high toxicity, side effects, and drug resistance. Herbal medicines are unlimited sources for discovering new medications to treat infectious diseases. This study aimed to examine the in vitro effect of hydroalcoholic extract of Artemisia absinthium on the growth of Leishmania major in peritoneal macrophages from BALB/c mice. In this experimental study, the hydroalcoholic extract of A. absinthium was prepared and dissolved in 2% dimethyl sulfoxide (DMSO). Leishmania major (MRHO/IR/75/ER) was cultured in RPMI1640 medium containing 15% fetal bovine serum (FBS). Peritoneal macrophages were extracted from BALB/c mice and were infected with promastigotes at a ratio of 1:10. The extract was added to Leishmania-infected macrophages and promastigotes at different concentrations. After 24, 48, and 72 hours, the effectiveness of A. absinthium on promastigotes was assessed using Trypan blue test and methyl thiazole tetrazolium (MTT) colorimetric assay, and the half maximal inhibitory concentration (IC50) of A. absinthium extract was obtained. Giemsa staining was used to evaluate the effect of A. absinthium extract on amastigotes. Also, inducible nitric oxide synthase (iNOs) level was measured from Leishmania-infected macrophages. The data were analyzed by ANOVA in SPSS software. The hydroalcoholic extract of A. absinthium showed a significant anti-Leishmania activity against promastigotes and amastigotes at various concentrations after 48 and 72 hours. The IC50 values of the alcoholic extract of A. absinthium were obtained at 56 mg/mL and 51 mg/mL concentrations of promastigotes and amastigotes, respectively. The lowest levels of iNOs were seen at 100 and 50 mg/mL concentrations of A. absinthium in treated macrophages. The former was obtained at 60.8 and 58.8 ng/mL after 24 and 48 hours and the latter at 55.5 ng/mL and 50 mg/mL of A. absinthium, respectively, after 72 hours. Findings of the present study showed the anti-parasitic effects of A. absinthium on both promastigotes and amastigotes. Further studies are recommended to be conducted on animal models and the active ingredients of A. absinthium extract to accurately assess the effects of this extract on the growth of L. major.

The correct identifying of pathogenic Burkholderia spp. using available commercial biochemical systems is a certain problem due to metabolic plasticity and variable enzymatic profile of isolates. The current study aimed at using specific PCR and conventional multi-locus sequence typing (MLST) scheme to confirm the uncertain identification results for Burkholderia cepacia clinical isolate. Multilocus species-specific PCR and MLST profiling of high-throughput sequencing data have been used to clarify the varied results of biochemical identification of the strain. The strain isolated from a patient with septicemia was initially identified as B. pseudomallei by Vitek 2 GN system but has an uncharacteristic antimicrobial resistance pattern and colony morphology. A species-specific multilocus PCR and whole-genome sequence profiling, according to the MLST scheme, allowed to identify an isolate as B. cepacia. The obtained results demonstrate the preference of molecular tests for correct identifying of pathogenic Burkholderia, considering that misidentification of those may lead to improper treatment or increase of biosafety risk.