P079 Virulence factors and azole-resistant mechanism of Candida tropicalis isolated from candidemia

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM

 

Background

Limited knowledge exists on the virulence factors of Candida tropicalis and the mechanisms of azole resistance that lead to an intensified pathogenicity and treatment failure. We aimed to evaluate the virulence factors and molecular mechanisms of azole resistance among C. tropicalis isolated from patients with candidemia.

Materials and Methods

Several virulence factors, including extracellular enzymatic activities, cell surface hydrophobicity (CSH), and biofilm formation were evaluated. Antifungal susceptibility pattern and expression level of ERG11, UPC2, MDR1, and CDR1 genes of 8 (4 fluconazole resistance and 4 fluconazole susceptible) clinical C. tropicalis isolates were assessed. The correlation between the virulence factors and antifungal susceptibility patterns was analyzed.

Results

During a 4-year study, 45 C. tropicalis isolates were recovered from candidemia patients. The isolates expressed different frequencies of virulence determinants as follows: coagulase 4 (8.9%), phospholipase 5 (11.1%), proteinase 31 (68.9%), esterase 43 (95.6%), hemolysin 44 (97.8%), biofilm formation 45 (100%), and CSH 45(100%). All the isolates were susceptible to amphotericin B and showed the highest resistance to voriconazole. There was a significant positive correlation between micafungin minimum inhibitory concentrations (MICs) and hemolysin production (rs = 0.316). However, we found a negative correlation between fluconazole MICs and esterase production (rs = −0.383). We observed the high expression of ERG11 and UPC2 genes in fluconazole-resistant C. tropicalis isolates.

Conclusion

Candida tropicalis isolated from candidemia patients extensively displayed capacities for biofilm formation, hemolysis, esterase activity, and hydrophobicity. In addition, the overexpression of ERG11 and UPC2 genes was considered one of the possible mechanisms of azole resistance.

Molecular identification of aflatoxigenic Aspergillus species in dried nuts and grains collected from Tehran, Iran

INTRODUCTION

Agricultural commodities contaminated by molds and mycotoxins can be considered as public health problems in less developed countries, particularly in Iran. Hence the main purpose of this study was to identify mold fungi and molecular analysis of the most important species of aflatoxin-B1-producing Aspergillus species in some dried nuts and grains in local markets in Tehran.

MATERIALS AND METHODS

Two hundred fifty samples of wheat, rice, corn, pistachios, and peanuts were collected from the five different locations of Tehran between January 2018 and January 2019. The samples were analyzed by using direct seed inoculation method and grain crushing method. Fungal strains were identified as Aspergillus spp. on the basis of morphological characters and further confirmed by using of β-tubulin gene sequencing. To differentiate between aflatoxigenic and non-aflatoxigenic Aspergillus spp., the isolates were screened for the presence of aflatoxigenic genes (nor-1, ver-1, omtA, and aflR).

RESULTS

One-handed forty-eight aflatoxigenic Aspergillus isolates (144 A. flavus and 4 A. parasiticus) were identified and aflR gene was the most frequent gene in these species. Five isolates (4 A. flavus, 1 A. parasiticus) had quadruplet pattern, 64 isolates (63 A. flavus, 1 A. parasiticus) had more than 1 gene and 39 isolates (38 A. flavus,1 A. parasiticus) did not have any genes.

CONCLUSION

According to the contamination of dried nuts and grains by some aflatoxigenic fungi, an extensive surveillance is necessary to provide a wider view on these products. Moreover, effective and efficient aflatoxin control program requires identifying and managing key elements that are effective in reducing mycotoxin production at farm level or in storage conditions.

Correction to: Molecular identification of aflatoxigenic Aspergillus species in dried nuts and grains collected from Tehran, Iran

[This corrects the article DOI: 10.1007/s40201-021-00734-6.].

Synthesis, Cytotoxicity Evaluation, and Antifungal Activity of Novel Nitroglycerin Derivatives against Clinical Candida albicans Isolates

Background

Candida albicans remains the main cause of candidiasis in most clinical settings. Available drugs for candidiasis treatment have many side effects. In this work, novel nitroglycerin derivatives were synthesized and their cytotoxic and antifungal effects evaluated against fluconazole susceptible and resistant clinical C. albicans isolates.

Methods

This experimental study was performed in Tehran University of Medical Sciences and Baqiatallah University of Medical Sciences, Tehran, Iran between Feb to Dec 2019. The in vitro activities of two novel nitroglycerin derivatives (1b and 2b) against 25 clinical fluconazole-susceptible and resistant C. albicans isolates and four standard C. albicans strains were determined according to CLSI reference M27-A3 documents. The cytotoxicity of chemical compounds was investigated near the SNL76/7 cells by colorimetric assay. Real-time PCRs were performed to evaluate the alterations in the regulation of ERG11 and CDR1 genes under nitroglycerin derivatives-treated and untreated conditions.

Results

The derivatives 1b and 2b exhibited potent antifungal activity against C. albicans isolates; MICs and MFCs varied from 18 μg/ml to 72 μg/ml and 36 μg/ml to 144 μg/ml, respectively. The cell viability evaluation demonstrated that both chemical compounds are safe within 24h. The nitroglycerin derivatives were able to reduce the transcription level of CDR1 and ERG11 genes in all susceptible and resistant C. albicans isolates.

Conclusion

Considering the potential and efficacy of these compounds against clinical C. albicans isolates, the complementary in vivo and clinical trials should be investigated.

First molecular report of causative agent of otomycosis due to Aspergillus luchuensis

Otomycosis is a fungal infection of the external auditory canal caused mainly by the genus Aspergillus. Aspergillus luchuensis, an industrially important fungus, is a member of Aspergillus section Nigri. In this report, we present a case of otomycosis due to Aspergillus luchuensis in a 43-year-old female patient. We performed a partial PCR-sequencing of β-tubulin and calmodulin genes to identify the isolate to the species level. Further, we determined the in vitro susceptibility of the isolate to nystatin, clotrimazole and itraconazole according to the Clinical & Laboratory Standards Institute (CLSI) M38-A2 protocol. Accordingly, the minimum inhibitory concentrations of clotrimazole, nystatin and itraconazole were 0.25μg/mL, 0.5μg/mL and 1μg/mL, respectively. This is the first report of clinically relevant isolation of Aspergillus luchuensis identified by a molecular technique as a causative agent of otomycosis.

Virulence Factors and Azole-Resistant Mechanism of Candida Tropicalis Isolated from Candidemia

BACKGROUND

Limited knowledge exists on the virulence factors of Candida tropicalis and the mechanisms of azole resistance that lead to an intensified pathogenicity and treatment failure. We aimed to evaluate the virulence factors and molecular mechanisms of azole resistance among C. tropicalis isolated from patients with candidemia.

MATERIALS AND METHODS

Several virulence factors, including extracellular enzymatic activities, cell surface hydrophobicity (CSH), and biofilm formation, were evaluated. Antifungal susceptibility pattern and expression level of ERG11, UPC2, MDR1, and CDR1 genes of eight (4 fluconazole resistance and 4 fluconazole susceptible) clinical C. tropicalis isolates were assessed. The correlation between the virulence factors and antifungal susceptibility patterns was analyzed.

RESULTS

During a 4 year study, forty-five C. tropicalis isolates were recovered from candidemia patients. The isolates expressed different frequencies of virulence determinants as follows: coagulase 4 (8.9%), phospholipase 5 (11.1%), proteinase 31 (68.9%), esterase 43 (95.6%), hemolysin 44 (97.8%), biofilm formation 45 (100%) and CSH 45(100%). All the isolates were susceptible to amphotericin B and showed the highest resistance to voriconazole. There was a significant positive correlation between micafungin minimum inhibitory concentrations (MICs) and hemolysin production (r_s = 0.316). However, we found a negative correlation between fluconazole MICs and esterase production (r_s = -0.383). We observed the high expression of ERG11 and UPC2 genes in fluconazole-resistant C. tropicalis isolates.

CONCLUSION

C. tropicalis isolated from candidemia patients extensively displayed capacities for biofilm formation, hemolysis, esterase activity, and hydrophobicity. In addition, the overexpression of ERG11 and UPC2 genes was considered one of the possible mechanisms of azole resistance.

Subtilisin Gene Activity in Dermatophytes: A study on the Presence of the Subtilisin Gene in Trichophyton verrucosum and Microsporum gypseum in Clinical and Nonclinical Samples in Tehran, Iran

The keratinolytic activities of dermatophyte species are accompanied by the secretion of enzymes, such as serine proteases, which are coded by the Subtilisin (SUB) genes. This study aimed to determine the presence of the SUB genes in the clinical and nonclinical samples of Trichophyton verrucosum and Microsporum gypseum. Isolation was carried out by direct and laboratory examination. Following that, for the determination of the presence of the SUB gene, polymerase chain reaction with specific primers was conducted. The frequencies of the SUB gene were observed in almost 66% of the isolates. Statistical analysis showed a significant relationship between the presence of the SUB gene and the samples collected from human, animals, and soil (p ˂0.005). The current investigation has been the first study of the presence/absence of the SUB gene in the clinical and nonclinical isolates of T. verrucosum and M. gypseum in Iran which may be a new step to perform further studies.

Molecular identification and clinical features of fungal rhinosinusitis: A 3-year experience with 108 patients

This study aimed to determine the prevalence, the causative agents, clinical features, and the risk factors associated with the fungal rhinosinusitis in a tertiary health center with a view to providing valid grounds that may guide healthcare professionals to effectively prevent, control, and treat fungal infections. All patients were subjected to diagnostic nasal endoscopy and CT scan of paranasal sinuses and FRS were confirmed by routine and complementary mycological and molecular methods. The inclusion criteria for invasive FRS were: confirmed diagnosis of IFRS according to the guidelines of the EORTC/MSG criteria (i.e., clinical, microbiological, and histological evidence of invasive fungal infection). From a total of 512 suspected patients, FRS was confirmed in 108 cases (21.1%). Our results showed FB (38/108; 35.2%) is the most common form of FRS followed by AIFRS (33/108; 30.6%), AFS (32/108; 29.6%), and CIFRS (5/108; 4.6%). A. flavus and Rhizopus oryzae were the most common causes of infection in AFS, FB, CIFRS, and AIFRS, respectively. Univariate analysis of variables predictive of AIFRS revealed 3 variables significantly associated with AIFRS. These included mucosal abnormalities of the middle turbinate and septum, and specifically, necrosis of the middle turbinate (P < .0001). Microbiological cultures, although useful for mycological speciation, are less sensitive. Furthermore, we used molecular methods to confirm the identity of some isolates that were not detectable using routine methods. Our data showed that the molecular methods and histologic diagnosis in all patients were more sensitive than the unenhanced sinus CT scan, and conventional microbiological methods.

Eco-friendly control of licorice aqueous extract to increase quality and resistance to postharvest decay in apple and tangerine fruits

BACKGROUND

Postharvest diseases in fruits and vegetables are one of the major problems in storing them as a fresh agri-product. This study aimed to investigate the antifungal activity of licorice (Glycyrrhiza glabra) aqueous extract against the Penicillium expansum and the Penicillium digitatum in apple and tangerine fruits as well as their postharvest decay during storage time.

METHODS

The minimum inhibitory concentration (MIC) of the molds, and the decay inhibition percentage (%DI) with the P.expansum for apple and P.digitatum for tangerine after treatment with licorice aqueous extract were measured. Additionally, the lesion diameter, titratable acidity (TA), total soluble solids (TSS), pH, and organoleptic properties were determined.

RESULTS

The growth of molds was almost inhibited at the concentration of 62.5 mg/mL. The ability of licorice aqueous extract to significantly control and reduce the growth of P. expansum in apple by 60 and 20 % after 7 days and 21 days of storage time was proved, respectively. Furthermore, significant differences in pH and TSS (p < 0.05) were observed in apples. Also, the growth of P. digitatum in the tangerine reduced by 33.3 % after 7 days, while there was no significant difference between the control and treatment groups in pH and TSS for apples, and similarly, there was no significant difference in TA for tangerine samples.

CONCLUSIONS

Therefore, the licorice aqueous extract treatment could postpone the blue mold decay in apple fruits and green mold decay in tangerine without any significant effect on fruit quality characteristics. It can be considered as a new eco-friendly control in fruit preservation, while it did not result in any significant adverse effect on  the quality.

The relationship between biofilm formation and mortality in patients with Candida tropicalis candidemia

BACKGROUND

Biofilm formation by Candida species is an influential virulence factor in candidemia pathogenesis. We investigated the relationship between biofilm formation of Candida tropicalis isolates with the clinical characteristics and mortality outcomes in patients with candidemia.

MATERIALS AND METHODS

Thirty-nine C. tropicalis isolates were recovered from patients with candidemia admitted to two university hospitals in Tehran, Iran. Biofilm mass and metabolic activity of C. tropicalis biofilms were assessed in vitro with two colorimetric methods. The sessile minimum inhibitory concentrations (SMICs) were evaluated in vitro by treating preformed biofilms with diluted concentrations of azoles according to CLSI-M27 A3/S4 protocol, followed by metabolic activity quantification. The expressions of ERG11, UPC2, MDR1, and CDR1 genes were also evaluated.

RESULTS

All C. tropicalis isolates produced biofilm. Respectively, higher <7-day and ≥7-day mortality rates were found among cases with high metabolic activity (46.7% vs. 13%, P = 0.03) and high biofilm mass (31.8% vs. 0, P = 0.029). Sessile cells had high resistance to fluconazole, voriconazole, and itraconazole. The azole minimum inhibitory concentrations (MICs) of C. tropicalis sessile were significantly greater than the planktonic minimum inhibitory concentrations (PMICs). In fluconazole-treated biofilms, the expression of ERG11 and UPC2 genes was increased.

CONCLUSION

Our findings highlight the importance of C. tropicalis biofilm formation as an important factor in candidemia pathogenesis and the clinical outcome of patients with candidemia.

The double-edged sword of systemic corticosteroid therapy in viral pneumonia: A case report and comparative review of influenza-associated mucormycosis versus COVID-19 associated mucormycosis

Acute respiratory distress syndrome is a common complication of severe viral pneumonia, such as influenza and COVID‐19, that requires critical care including ventilatory support, use of corticosteroids and other adjunctive therapies to arrest the attendant massive airways inflammation. Although recommended for the treatment of viral pneumonia, steroid therapy appears to be a double‐edged sword, predisposing patients to secondary bacterial and invasive fungal infections (IFIs) whereby impacting morbidity and mortality. Mucormycosis is a fungal emergency with a highly aggressive tendency for contiguous spread, associated with a poor prognosis if not promptly diagnosed and managed. Classically, uncontrolled diabetes mellitus (DM) and other immunosuppressive conditions including corticosteroid therapy are known risk factors for mucormycosis. Upon the background lung pathology, immune dysfunction and corticosteroid therapy, patients with severe viral pneumonia are likely to develop IFIs like aspergillosis and mucormycosis. Notably, the combination of steroid therapy and DM can augment immunosuppression and hyperglycaemia, increasing the risk of mucormycosis in a susceptible individual. Here, we report a case of sinonasal mucormycosis in a 44‐year‐old woman with hyperglycaemia secondary to poorly controlled diabetes following dexamethasone therapy on a background of influenza pneumonia and review 15 available literatures on reported cases of influenza and COVID‐19 associated mucormycosis.

Experiences of the mothers of infants hospitalized in the neonatal intensive care unit (NICU)

BACKGROUND

The mother-newborn relationship is more important in neonates hospitalized in the NICU than in healthy neonates. This study was conducted to explore the experiences of the mothers of infants hospitalized in the NICU.

MATERIALS AND METHODS

This qualitative study was done in 2016 by adopting a conventional content analysis approach. Thirty-five mothers in the NICUs, Imam Hossein Hospital and Fatemieh Hospital were selected. Their experiences were assessed using in-depth individual semi-structured interviews. Sampling was purposive and was continued until reaching data saturation.

RESULTS

Two hundred and nine primary codes were extracted. After removing duplicates and overlaps, 95 primary codes were categorized in 8 subcategories, 2 accessory categories and 1 main category based on their appropriateness, agreement, and similarity. The accessory categories of "mothers' worries" and "mothers' hopes" were merged into a more general, abstract category named "dual feelings about the baby".

CONCLUSIONS

The nurses' awareness of the mothers' experiences can help design interventions to promote the quality of care for mothers and infants in the critical period of the NICU admission.

Biocontrol effect of Kluyveromyces lactis on aflatoxin expression and production in Aspergillus parasiticus

Aspergillus parasiticus is one of the most common fungi able to produce aflatoxins, which are naturally occurring carcinogenic substances. This study evaluated the effects of the safe yeast, Kluyveromyces lactis, on fungal growth, aflatoxin production and expression of aflR gene in A. parasiticus. Antifungal susceptibility was evaluated by exposing A. parasiticus to different amounts of K. lactis, and aflatoxin production was measured using high-performance liquid chromatography. Expression of the aflR gene was determined by measuring the cognate aflR mRNA level by quantitative real-time reverse-transcription polymerase chain reaction assay. The growth of A. parasiticus was inhibited by 7 days of incubation at 30°C with a minimum population of 1.5 × 105 CFU/ml of K. lactis, which also suppressed expression of the A. parasiticus aflR gene, reducing the total production of aflatoxins by 97.9% and aflatoxins B1, B2, G1 and G2 by 97.8, 98.6, 98 and 94%, respectively. Accordingly, K. lactis could be considered as a potential biocontrol agent against toxigenic molds in food and animal feed.

Evaluation of phenotypes and genotypes of airborne Fungi during middle eastern dust storms

Microbial species such as bacteria and fungi can be transported by dust storms over long distances, and may change the mycobiota in downwind. This study aimed to evaluate phenotypes and genotypes of airborne fungi during the Middle Eastern dust (MED) events and normal days in Khorramabad, Iran. The samples were collected regularly every six days at three locations during April 2018-March 2019, with additional samplings during MED days. For phenotypic analyses, the Petri dishes were incubated at 25 °C for 72-120 h. Molecular identification of fungi was carried out using polymerase chain reaction (PCR). The average (±SD) of total fungal concentration was 460.9 (±493.2) CFU/m³. The fungi with the highest average concentrations included Cladosporium cladosporioides, Penicillium brevicompactum, and Cladosporium iridis, respectively. The average concentration of fungi during dust days (967.65 CFU/m³) was 3.6 times higher than those in normal days (267.10 CFU/m³). During normal and dust days, 61 and 45 species were detected, respectively. Aspergillus and Cladosporium spp. were relatively more dominant during normal and dust days, respectively. Eight fungal species were only observed during MED days, including Talaromyces albobiverticillius that was detected for the first time in Iran. Despite air temperature, relative humidity and wind speed were associated to the fungal concentrations. Dust events lead to the changes in the air pollutants composition and mycobiota, identification of new fungi, and elevated fungal concentrations that may extremely affect the public health.

Molecular identification, phylogenetic analysis and antifungal susceptibility patterns of Aspergillusnidulans complex and Aspergillusterreus complex isolated from clinical specimens

OBJECTIVE

Aspergillus sections Terrei and Nidulantes are the less common causes of invasive aspergillosis and pulmonary aspergillosis (PA) in immunocompromised patients when compared to A. fumigatus and A. flavus. Identifying these fungi as the infectious agent is crucial because of the resistance to amphotericin B (AMB) and increased lethality. The aim of this study was to identify the molecular status, evaluate the genetic diversity and examine the antifungal susceptibility profile of the uncommon Aspergillus species. Forty-five uncommon Aspergillus species were identified based on the microscopic and macroscopic criteria. Then, the molecular identification was performed using the sequencing beta tubulin (benA) gene. In vitro antifungal susceptibility to amphotericin B (AMB), itraconazole (ITC), ravuconazole (RAV), voriconazole (VRC), caspofungin (CFG) isavuconazole (ISA) and posaconazole (POS) test was performed according to the CLSI M38-A2 guidelines.

RESULTS

A. terreus was the most species detected, followed by A. nidulans, A. latus, A.ochraceus, and A. citrinoterreus, respectively. The analysis of the benA gene showed the presence of 12 distinct genotypes among the A. terreus isolates. The other species did not show any intraspecies variation. CFG exhibited the lowest MEC₅₀/MIC₅₀ (0.007μg/mL), followed by POS (0.125μg/mL), VRC, ITC, ISA (0.25μg/mL), RAV (0.5μg/mL), and AMB (8μg/mL). Among all the isolates, only 15.5% (7/45) were susceptible to AMB.

CONCLUSION

Antifungal susceptibility pattern of the uncommon Aspergillus species is useful to improve patient management and increase knowledge concerning the local epidemiology. Moreover, this information is necessary when an outbreak dealing with drug-resistant infections occurs.

Comparative in vitro activities of seven antifungal drugs against clinical isolates of Candida parapsilosis complex

OBJECTIVE

Candida parapsilosis species complex, an important set of non-albicans Candida species, is known to cause candidaemia particularly in neonates and infants. However, the incidence has increased in recent years, owing to higher numbers of at individuals at risk for these infections. Our objective was to evaluate the in vitro susceptibility of clinical isolates of C. parapsilosis complex isolates from Iran to seven antifungal drugs.

MATERIAL AND METHODS

One hundred-one clinical isolates of C. parapsilosis species complex cultured from humans were included. Species identification had been previously confirmed by combined phenotypic characteristics, matrix-assisted laser desorption ionization-time of flight mass spectrometry-based assay and reconfirmed by DNA sequence analysis of the ITS rDNA region and D1/D2 gene. Minimum inhibitory concentrations (MICs) for amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, micafungin and anidulafungin were determined against well-characterized isolates by broth microdilution susceptibility testing according to the CLSI M27-A3 guideline.

RESULTS

Species identifications were performed on 101 isolates, of which 88 (87.2%) C. parapsilosis sensu stricto and 13 (12.8%) C. orthopsilosis. Amphotericin B and posaconazole were the most active drugs with 100% of isolates being wild-type (WT). Voriconazole and micafungin, 99% of isolates were WT. The low activity was recorded for fluconazole and itraconazole with 93.1% and 89.1% of isolates being WT, respectively. At the species level, all Candida parapsilosis sensu stricto isolates were WT to amphotericin B and posaconazole and all Candida orthopsilosis isolates were WT to amphotericin B, voriconazole, posaconazole, anidulafungin and micafungin. In contrast, the highest rate of non-WT was observed in C. orthopsilosis to itraconazole (4 of 13, 30.8%).

CONCLUSIONS

Although almost all of the tested drugs demonstrated potent activity against C. parapsilosis species complex, it seems that more especially C. orthopsilosis isolates had decreased susceptibility to itraconazole. Further studies are needed to determine how these findings may switch into in vivo efficacy.

Antifungal susceptibility pattern and biofilm-related genes expression in planktonic and biofilm cells of Candida parapsilosis species complex

Background and Purpose:

Candida parapsilosis complex isolates are mainly responsible for nosocomial catheter-related infection in immunocompromised patients. Biofilm formation is regarded as one of the most pertinent key virulence factors in the development of these emerging infections. The present study aimed to compare in vitro antifungal susceptibility patterns and biofilm-related genes expression ratio in planktonic and biofilm’s cells of clinically C. parapsilosis complex isolates.

Materials and Methods:

The current study was conducted on a number of 17 clinical C. parapsilosis complex (10 C. parapsilosis sensu stricto, 5 C. orthopsilosis, and 2 C. metapsilosis). The antifungal susceptibility patterns of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin in planktonic and biofilm forms were closely examined using CLSI M27-A3 broth microdilution method. The expression levels of biofilm-related genes (BCR1, EFG1, and FKS1) were evaluated in planktonic and biofilm’s cells using Real-time polymerase chain reaction (PCR) technique.

Results:

The obtained results indicated that all C. parapsilosis complex isolates were able to produce high and moderate amounts of biofilm forms. In addition, the sessile minimum inhibitory concentrations were reported to be high for fluconazole (≥ 64 µg/ml), itraconazole, voriconazole, and posaconazole (≥ 16 µg/ml), as compared to planktonic minimum inhibitory concentrations. Moreover, a significant difference was observed between antifungal susceptibility patterns for all azole antifungal agents (P<0.05). Furthermore, the BCR1 overexpression was considered significant in biofilms with regard to planktonic cells in C. parapsilosis species complex (P=0.002).

Conclusion:

C. parapsilosis complex isolates were found susceptible to most of the tested antifungal drugs, while biofilms demonstrated a noticeable resistant to azoles. The marked discrepancy noted in antifungal susceptibility patterns among these species should be highlighted to achieve effective therapeutic treatment.

Aflatoxin M1 contamination level in Iranian milk and dairy products: a systematic review and meta-analysis

Aflatoxin M1 is a derivate of aflatoxin B1 and an important contaminant of milk and dairy products. This systematic review and meta-analysis was conducted on relevant Persian and English original articles in national and international databases with no time limits until 1 January 2018. In total 605 articles were found among which 70 articles met the inclusion criteria for meta-analysis. The prevalence (95% confidence interval (CI)) and mean concentration (95% CI) of aflatoxin M1 was found to be 64% (53-75%) and 39.7 ng/l (31.9-47.4 ng/l) in raw milk, 95% (89-98%) and 62.3 ng/l (40.6-84 ng/l) in pasteurised milk, 71% (56-84%) and 60.1 ng/l (30.9-89.3 ng/l) in sterilised milk, 59% (20-93%) and 5.5 ng/l (3.3-7.7 ng/l) in breast milk and 72% (61-81%) and 82.3 ng/kg (63.7-100.9 ng/kg) in dairy products. In general, 9% (4-16%) of milks and 10% (4-17%) of dairy products had aflatoxin M1 in concentrations exceeding the permitted level of Iranian standards (500 ng/l). Based on the maximum permitted aflatoxin M1 concentration in standards of Europe (50 ng/l), these percentages increase to 25% (18-32%) for milks and 18% (9-29%) for dairy products. According to the results, further control and preventive measures should be applied on livestock feeds because decreased aflatoxin B1 contamination at this level results in decreased aflatoxin M1 in milk and dairy products.

Comparison of in vitro antifungal activity of novel triazoles with available antifungal agents against dermatophyte species caused tinea pedis

OBJECTIVE

Dermatophytes are a group of keratinophilic fungi that invade and infect the keratinized tissues and cause dermatophytosis. We investigated effectiveness of novel triazole (luliconazole and lanaconazole) in comparison with available antifungal agents against dermatophyte species isolated from patients with tinea pedis.

MATERIAL AND METHODS

A total of 60 dermatophytes species were isolated from the patients with tinea pedis. Identification of species was done by DNA sequencing of the ITS1-5.8S rDNA-ITS2 rDNA region. In vitro antifungal susceptibility testing with luliconazole and lanaconazole and available antifungal agent was done in accordance with the Clinical and Laboratory Standards Institute, M38-A2 document.

RESULTS

In all investigated isolates, luliconazole had the lowest minimum inhibitory concentration (MIC) (MIC range=0.0005-0.004μg/mL), while fluconazole (MIC range=0.4-64μg/mL) had the highest MICs. Geometric mean MIC was the lowest for luliconazole (0.0008μg/mL), followed by lanoconazole (0.003μg/mL), terbinafine (0.019μg/mL), itraconazole (0.085 μg/mL), ketoconazole (0.089μg/mL), econazole (0.097μg/mL), griseofulvin (0.351 μg/mL), voriconazole (0.583μg/mL) and fluconazole (11.58μg/mL).

CONCLUSION

The novel triazoles showed potent activity against dermatophytes and promising candidates for the treatment of tinea pedis caused by Trichophyton and Epidermophyton species. However, further studies are warranted to determine the clinical implications of these investigations.

Antifungal susceptibility of non-albicans Candida spp. isolated from raw milk and human blood in Alborz and Tehran provinces

BACKGROUND AND OBJECTIVES

Recent reports indicate high prevalence of fungal infections due to non-albicans Candida spp. which are present in various environments such as raw milk. The quality of milk for fungal normal flora was investigated in this study.

MATERIALS AND METHODS

A total of 262 milk samples were collected directly from milk collection tanks indesignated dairy farms and cultured in SDA media. By further analysis of grown yeasts, 69 non-albicans Candida strains were identified. Antifungal susceptibility of the isolated species, were evaluated against amphotericin B, itraconazole, fluconazole and flucytosine. Fifty two non-albicans clinical samples isolated from human blood have been evaluated along.

RESULTS

Antifungal susceptibility evaluation in non-albicans strains isolated from milk revealed Candida glabrata and Candida tropicalis to be 100% sensitive to flucytosine and fluconazole. Candida krusei showed 94% and 80% sensitivity to flucytosine and fluconazole respectively. Candida parapsilosis indicated 72.72% sensitivity to fluconazole.

CONCLUSION

Evaluation of non-albicans Candida species in raw milk and antifungal susceptibility patterns of these isolates-compare with non-albicansisolates from human blood, may help physicians to choose an appropriate medication for diseases needing long-term treatment, especially for diseases caused by local strains.

A simple and accurate PCR method for detection of genetically modified rice

BACKGROUND

Legislation regulating for labeling and use of genetically modified (GM) crops are increased considerably worldwide in order to health and safety assurance of consumers. For this purpose, a polymerase chain reaction (PCR) method has been developed for detection of GM rice in people's food diet.

METHODS

In this study, eighty-one non-labeled rice samples were collected randomly from different market sites of Tehran, Iran. In order to analysis, rice genomic DNA was extracted using MBST DNA extraction kit and subsequently, sucrose phosphate synthase (SPS) gene was used to confirm the quality of extracted DNA. Then, cauliflower mosaic virus (CaMV) 35S promoter and Agrobacterium nopaline synthase (NOS) terminator were selected as screening targets for detection of GM rice sequences by PCR.

RESULTS

According to our results, 2 out of 81 (2.4%) samples tested were positive for CaMV 35S promoter while no positive result was detected for NOS terminator.

CONCLUSION

The obtained data indicated that this method is capable to identify the GM rice varieties. Furthermore, it can demonstrate the possibility of the presence of GM rice in Tehran's market, thus putting emphasis on the requirement for developing a precise approach to evaluate this product.

In vitro synergy of echinocandins with triazoles against fluconazole-resistant Candida parapsilosis complex isolates

INTRODUCTION

Candida parapsilosis (C. parapsilosis) is a common non-albicans Candida species ranked as the second common cause of bloodstream infections. Azole resistance and elevated echinocandin MICs have been reported for these fungi. This study was conducted to determine the interactions between azoles and echinocandins against C. parapsilosis species complex.

MATERIALS AND METHODS

Fifteen fluconazole-resistant clinical isolates of C. parapsilosis complex were included: C. parapsilosis sensu stricto (n = 7), C. orthopsilosis (n = 5) and C. metapsilosis (n = 3). The activity of azoles (fluconazole, itraconazole) and echinocandins (anidulafungin, micafungin) alone and in combination was determined using checkerboard broth microdilution. The results were determined based on the fractional inhibitory concentration index (FICI).

RESULTS

In vitro combination of fluconazole with anidulafungin was found to be synergistic (FICI 0.07-0.37) and decreased the MIC range from 4-64 μg/mL to 0.5-16 μg/mL for fluconazole and from 2-8 μg/mL to 0.125-1 μg/mL for anidulafungin. Similarly, interactions of fluconazole with micafungin (FICI 0.25-0.5), itraconazole with anidulafungin (FICI 0.15-0.37) and itraconazole with micafungin (FICI 0.09-0.37) were synergistic.

CONCLUSION

The combination of fluconazole and itraconazole with either anidulafungin or micafungin demonstrated synergistic interactions against C. parapsilosis species complex, especially against isolates with elevated MIC values. However, the use of these combinations in clinical practice and the clinical relevance of in vitro combination results remain unclear.

Investigation of cgrA and cyp51A gene alternations in Aspergillus fumigatus strains exposed to kombucha fermented tea

BACKGROUND AND PURPOSE

Aspergillus fumigatus is one of the most common opportunistic fungus, which causes infection in immunocompromised and neutropenic patients. The current guidelines recommend voriconazole as the initial therapeutic and prophylactic agent for almost all cases, especially in patients with organ transplants, which leads to increased medication resistance in A. fumigatus. The aim of the present study was to evaluate the antifungal activity and effect of kombucha as a natural compound on A. fumigatus growth, as well as on the expression of cgrA and cyp51A genes.

MATERIALS AND METHODS

A panel of 15 A. fumigatus strains with two quality controls of CM237 and CM2627 as susceptible and resistant strains were obtained from Tehran Medical Mycology Laboratory, Tehran,Iran(TMML).Antifungal susceptibility testing assay was performed according to the Clinical and Laboratory Standards Institute (CLSI) M38-A2 document. Moreover, the mycelial dry weight of the fungus was calculated before and after being treated with kombucha. In addition, the quantitative changes in the expression of cgrA and cyp51A genes were analyzed by real-time polymerase chain reaction (real-time PCR) technique.

RESULTS

In the present study, the minimum inhibitory concentration ranges of kombucha were measured at 6,170 and 12,300 μg/mL for ten A. fumigatus azole-susceptible strains and 24,700 μg/mL for five A. fumigatus resistant strains. Moreover, changes in mycelial dry weight under kombucha treatment conditions underwent a significant reduction (P≤0.05). A coordinate down-regulation of expression in cgrA and cyp51A genes was observed in all azole-susceptible and -resistant A. fumigatus strains, after treating the fungus with different concentrations of kombucha (P≤0.05).

CONCLUSION

According to the obtained results, kombucha as a natural antioxidant , can exert inhibitory effects against the growth and expression of some genes in A. fumigatusstrains.

A simple and low cost tetra-primer ARMS-PCR method for detection triazole-resistant Aspergillus fumigatus

The mutation at codon L98 accompanied by a tandem repeat of 34 base pairs (TR₃₄/L98H) in the 5´upstream region of cyp51A is the principal mechanism of triazole resistance of Aspergillus fumigatus. We aimed to evaluate a simple and low-cost tetra-primer amplification refractory mutation system (ARMS)-PCR technique for detection of TR₃₄/L98H mutations in the cyp51A gene of azole-resistant A. fumigatus. The tetra-primer ARMS-PCR assay optimized by four primers in one reaction consists of external primers for detection of tandem repeats in the promoter region and internal primers for detection of a point mutation in codon 98 (L98H) in the cyp51A gene of azole-resistant A. fumigatus. The specificity of TR₃₄/L98H mutation detection was assessed by testing 36 clinical and environmental A. fumigatus strains. The tetra-primer ARMS-PCR assay from A. fumigatus, containing wild-type sequence (T allele) and L98H mutation at cyp51A (A allele), yielded two DNA fragments of 908 bp and 740 bp and two of 942 bp and 212 bp, respectively. None of the A. fumigatus isolates without the TR₃₄/L98H mutation yielded false-positive results. The ARMS-PCR assay was 100% concordant with DNA sequencing results. Prevalence and screening of the TR₃₄/L98H mutation in the cyp51A gene in A. fumigatus isolates may now be determined by a fast, low-cost, and simple method in resource-poor settings.

Influence of postharvest application of chitosan combined with ethanolic extract of liquorice on shelflife of apple fruit

BACKGROUND

Edible coatings are useful method that applied to preserve postharvest quality of production. The coatings can extend the shelf life of products and inhibit microbial growth. Chitosan based coatings are one of the best methods to prolong fruit and vegetable shelf life. The antimicrobial and other properties of chitosan are developed when it is combined with other functional ingredients.

METHODS

The effectiveness of chitosan, ethanolic extract of liquorice (LE) and complex of chitosan-liquorice extract (CHLE) was evaluated for controlling blue mold and extending shelf life in apples. The fruits were coated with chitosan(1.0%), LE (62.5 mg/ml) and CHLE coating, and stored at 25 °C. Quality properties of fruit (such as weight loss, firmness, total soluble solid content(TSS), titrable acidity and pH) and decay incidence were assessed on 0,1,4,7 and 14 days of incubation, respectively.

RESULTS

The results of experiments indicated that minimum of water loss(3.8%), TSS(14.53) and firmness(5.6 kg/cm² ) were in CHLE coated apples. In addition, this coating significantly inhibited penicillium expansum during the storage and the lowest decay incidence was for apples coated with CHLE(29 mm). Chitosan and LE coating retarded undesirable changes during postharvest storage and inhibited decay incidence compared with uncoated samples. There was no significant difference (p ≤ 0/05) between treatments and control overtime in terms of titrable acidity and pH levels.

CONCLUSIONS

The results reported here indicate importance and efficacy of CHLE coating in extending shelflife and reduction of postharvest losses of apple in storage time.

Optimization and Comparison of Different Methods and Factors for Efficient Transformation of Brucella abortus RB51strain

Background:

The development of protective vaccines for Brucella spp. has been hampered by the difficulty in transformation of Brucella cells with foreign DNA for genetic manipulation. It seems that the formation of Brucella spheroplasts would increase the efficiency of transformation. The aim of this study was to devise an efficient method for the transformation of Brucella spp.

Materials and Methods:

At first, spheroplast of Brucella was prepared by glycine and ampicillin induction and transformed using optimized protocols of CaCl₂, electroporation, and lipofection methods. Then, the efficacy of transformation was compared between the three-mentioned methods.

Results:

Ampicillin-induced spheroplasts from early-log phase culture of brucella when incubated in a medium-containing 0.2 M sucrose during cell recovery had higher transformation efficiency in three different methods. Comparison of the transformation efficiency of Brucella abortus RB51 using the CaCl₂, lipofection, and electroporation methods revealed that the transformation efficiency with the lipofection method was significantly higher than with other two methods (P < 0.05).

Conclusions:

Lipofection method by lipofectamine 2000 on ampicillin-induced spheroplasts can be a suitable approach for Brucella transformation.

Molecular characterization of bacterial, viral and fungal endosymbionts of Acanthamoeba isolates in keratitis patients of Iran

Free-living amoebae belong to the genus Acanthamoeba; can feed on microbial population by phagocytosis, and with the capability to act as a reservoir and a vehicle of microorganisms to susceptible host. Therefore, the role of endosymbiosis in the pathogenesis of Acanthamoeba is complex and not fully understood. The aim of the present study was to identify bacterial, fungal, and human adenovirus (HADV) endosymbionts as well as evaluating the endosymbionts role of such organisms in the pathogenesis of Acanthamoeba in keratitis patients living in Iran. Fifteen Acanthamoeba (T4 genotype) isolates were recovered from corneal scrapes and contact lenses of patients with keratitis. Cloning and purification was performed for all isolate. Gram staining was performed to identify bacterial endosymbionts. DNA extraction, PCR, and nested PCR was set up to identify endosymbiont of amoeba. Evaluation of pathogenicity was conducted by osmo-tolerance and thermo-tolerance assays and cell culture, and then CPE (cytopathic effect) was survey. Statistical analysis was used between Acanthamoeba associated endosymbionts and Acanthamoeba without endosymbiont at 24, 48, 72, and 96 h. A p value < 0.05 was considered as significant, statistically. A total of 9 (60%) Acanthamoeba (T4 genotypes) isolates were successfully cloned for detecting microorganism endosymbionts. The only isolate negative for the presence of endosymbiont was ICS9. ICS7 (Pseudomonas aeruginosa, Aspergillus sp., and human adenovirus endosymbionts) and ICS2 (Escherichia coli endosymbiont) isolates were considered as Acanthamoeba associated endosymbionts. ICS7 and ICS2 isolates were highly pathogen whereas ICS9 isolate showed low pathogenicity in pathogenicity evaluated. Positive CPE for ICS7 and ICS2 isolates and negative CPE for ICS9 isolate were observed in cell culture. The average number of cells, trophozoites, and cysts among ICS7, ICS2, and ICS9 isolates at 24, 48, 72, and 96 h was significant. This is the first survey on microbial endosymbionts of Acanthamoeba in keratitis patients of Iran, and also the first report of Aspergillus sp, Achromobacter sp., Microbacterium sp., Brevibacillus sp, Brevundimonas sp and Mastadenovirus sp in Acanthamoeba as endosymbionts. Our study demonstrated that microbial endosymbionts can affect the pathogenicity of Acanthamoeba; however, further research is required to clarify the exact pattern of symbiosis, in order to modify treatment protocol.

Comparison of biofilm-producing ability of clinical isolates of Candida parapsilosis species complex

OBJECTIVE

Candida parapsilosis is one of the main emerging non-Candida albicans species leading to superficial and systemic fungal infections in humans. Candida has the ability to produce biofilms associated with pathogenesis. The aim of the study was to estimate biofilm-producing ability of clinical isolates of C. parapsilosis sp. complex.

METHODS

Clinical samples of C. parapsilosis complex have been analyzed. Crystal violet (CV) staining and tetrazolium reduction assay (MTT) have been used to analyze the clinical isolates ability to produce biofilms. The biofilm's structural characteristics have been assessed by using scanning electron microscopy.

RESULTS

All 65 isolates were able to form biofilm. In addition, no significant difference was found between biofilm quantification based on two assays at different time intervals (24h, 48h, 72h, 96h) (P>0.05), with the exception of Candida orthopsilosis, which exhibited higher metabolic activity at 24h time point (P<0.05). Moreover, metabolic activity and production of biofilm biomass demonstrated statistically significant correlation (r=0.685, P<0.01). According to microscopic observations, the investigated clinical strains formed the similar surface topography with the slight differences in morphology; in addition, there was no statistically significant difference between efficiency of two assays to quantify biofilm.

CONCLUSION

It was shown that, similar to C. parapsilosissensu stricto, two cryptic identified species (C. orthopsilosis and Candida metapsilosis) obtained from different clinical samples, were biofilm producers, while C. parapsilosissensu stricto exhibited the highest biofilm production.

Comparison of 21-Plex PCR and API 20C AUX, MALDI-TOF MS, and rDNA Sequencing for a Wide Range of Clinically Isolated Yeast Species: Improved Identification by Combining 21-Plex PCR and API 20C AUX as an Alternative Strategy for Developing Countries

Occurrence of non-Candida albicans Candida (NCAC) species that are associated with elevated MIC values and therapeutic failures are increasing. As a result, timely and accurate means of identification to the species level is becoming an essential part of diagnostic practices in clinical settings. In this study, 301 clinically isolated yeast strains recovered from various anatomical sites [Blood (n = 145), other sites (n = 156)] were used to assess the accuracy and practicality of API 20C AUX and 21-plex PCR compared to MALDI-TOF MS and large subunit rDNA (LSU rDNA). MALDI-TOF MS correctly identified 98.33% of yeast isolates, 100% of top five Candida species, 95.7% of rare yeast species, while 1.3% of isolates were misidentified. API 20C AUX correctly identified 83.7% of yeast isolates, 97.2% of top five Candida species, 61.8% of rare yeast species, while 16.2% of yeast isolates were misidentified. The 21-plex PCR, accurately identified 87.3% of yeast isolates, 100% of top five Candida species, 72% of rare yeast species, but it misidentified 1.3% of rare yeast species while 9.9% of whole yeast isolates were not identified. The combination of rapidity of 21-plex PCR and comprehensiveness of API 20C AUX, led to correct identification of 92% of included yeast isolates. Due to expensiveness of MALDI-TOF MS and sequencing, this combination strategy could be the most accurate and inexpensive alternative identification strategy for developing countries. Moreover, by the advent and development of cost-effective, reliable, and rapid PCR machines that cost 130 US dollars, 21-plex could be integrated in routine laboratories of developing and resource-limited countries to specifically identify 95% causative agents of yeast-related infections in human. Databases of MALDI-TOF MS, API 20C AUX, and the number of target species identified by 21-plex require further improvement to keep up with the diverse spectrum of yeast species.

Assessment of the Inhibitory Effects of Ficin-hydrolyzed Gelatin Derived from Squid (Uroteuthis duvauceli) on Breast Cancer Cell Lines and Animal Model

Marine novel natural products have been applied for cancer therapy. Enzyme-digested gelatin hydrolysates have proven to serve as promising sources of potent biologically active peptides. Potential anti-breast cancer properties of the extracted Ficin-digesterd gelatin hydrolysate from Indian squid (Uroteuthis duvauceli) was extensively characterized by cellular and animal models. Gelatin was extracted from squid skin, hydrolyzed by Ficin, and characterized by standard physico-chemical methods. Ficin-digested gelatin hydrolysate was used at various doses of 0-0.1 mg/mL for assessment of MCF-7 and MDA-MB-231 breast cancer cells versus HUVEC normal cells. Cytotoxicity, phase-contrast morphological examination, apoptosis/necrosis, clonal-growth, cell-migration, Matrix-metalloproteinases (MMPs) zymography, and Western blotting were used for cellular assessments. For animal studies, breast tumor-induced BALB/c mice received hydrolyzed gelatin regimen, followed by tumor size/growth and immune-histochemical analyses. Significant inhibition of MCF-7 and MDA-MB-231 with no cytotoxicity on HUVEC cells were detected. Apoptosis was increased in cancer cells, as revealed by elevated ratio of cleaved caspase-3 and PARP. MMP-2 and MMP-9 activities in both cancer cells were diminished. In mice, gelatin hydrolysate prevented weight loss, decreased tumor size, induced p53, and down-regulated Ki67 levels. These findings suggest that Ficin-digested gelatin hydrolysate could be a beneficial candidate for novel breast cancer therapies.

Assessment of the Inhibitory Effects of Ficin-hydrolyzed Gelatin Derived from Squid (Uroteuthis duvauceli) on Breast Cancer Cell Lines and Animal Model

Marine novel natural products have been applied for cancer therapy. Enzyme-digested gelatin hydrolysates have proven to serve as promising sources of potent biologically active peptides. Potential anti-breast cancer properties of the extracted Ficin-digesterd gelatin hydrolysate from Indian squid (Uroteuthis duvauceli) was extensively characterized by cellular and animal models. Gelatin was extracted from squid skin, hydrolyzed by Ficin, and characterized by standard physico-chemical methods. Ficin-digested gelatin hydrolysate was used at various doses of 0-0.1 mg/mL for assessment of MCF-7 and MDA-MB-231 breast cancer cells versus HUVEC normal cells. Cytotoxicity, phase-contrast morphological examination, apoptosis/necrosis, clonal-growth, cell-migration, Matrix-metalloproteinases (MMPs) zymography, and Western blotting were used for cellular assessments. For animal studies, breast tumor-induced BALB/c mice received hydrolyzed gelatin regimen, followed by tumor size/growth and immune-histochemical analyses. Significant inhibition of MCF-7 and MDA-MB-231 with no cytotoxicity on HUVEC cells were detected. Apoptosis was increased in cancer cells, as revealed by elevated ratio of cleaved caspase-3 and PARP. MMP-2 and MMP-9 activities in both cancer cells were diminished. In mice, gelatin hydrolysate prevented weight loss, decreased tumor size, induced p53, and down-regulated Ki67 levels. These findings suggest that Ficin-digested gelatin hydrolysate could be a beneficial candidate for novel breast cancer therapies.

MGL_3741 gene contributes to pathogenicity of Malassezia globosa in pityriasis versicolor

Dihydroxyacid dehydratase (DHAD) is a key enzyme in biosynthetic pathway of isoleucine and valine. This pathway is absent in human but exists in various organisms such as fungi. Using RNA-seq analysis in this study, we identified MGL_3741gene which encodes DHAD protein in Malassezia globosa (M. globosa). Furthermore, we found that mentioned gene is homologous to the Ustilago maydis, Saccharomyces cerevisiae, Aspergillus flavus, and Aspergillus fumigatus ILV3P. For understanding the probable role of this gene in pathogenicity of M. globosa, we applied Real-time PCR to investigate the differentially expressed of the MGL_3741 gene in healthy and pathogenic states. Our results indicate a significant difference between two mentioned stats. These results revealed that ILV3-like gene in M. globosa can be related to the pathogenicity of this yeast.

Fungal keratitis: An overview of clinical and laboratory aspects

Mycotic keratitis or keratomycosis is a fungal infection with global distribution. The dominant aetiology of this disease varies based on geographical origin, socioeconomic status, and climatic condition. Generally, Aspergillus spp. and Fusarium spp. are common in tropical and subtropical regions and Candida spp. are dominant in temperate areas. Demonstration of fungal elements in microscopic examination besides the isolation of fungi in culture is the gold standard of laboratory diagnosis. As the culture is a time-consuming procedure, other approaches such as in vivo confocal microscopy which produces real-time imaging of corneal tissue and molecular techniques have been developed to facilitate rapid diagnosis of fungal keratitis. The first choice of treatment is topical natamycin, although topical amphotericin B is the best choice for Aspergillus and Candida keratitis. Regarding the diversity of fungal aetiology and the emergence of drug resistance in some genera and species, proper identification using molecular methods and antifungal susceptibility testing could provide useful data. Furthermore, as the better efficacy of combination therapy in comparison to monotherapy is reported, in vitro determination of interactions between various drugs seem informative. This review aims to provide a general and updated view on the aetiology, risk factors, epidemiology, clinical and laboratory diagnosis, and management of fungal keratitis.

Morphological changes and induction of antifungal resistance in Aspergillus fumigatus due to different CO2 levels

Background and Purpose

Aspergillosis is one of the most common opportunistic fungal infections in immunocompromised and neutropenic patients. Aspergillus fumigatus (A. fumigatus) is the most common causative agent of this infection. Due to variable CO₂ concentrations that pathogens are exposed to during the infection process and to understand the role of CO₂, we examined the effects of various CO₂ concentrations as one of the environmental factors on morphological changes and induction of antifungal resistance in A. fumigatus.

Materials and Methods

A. fumigatus strains were cultured and incubated under 1%, 3%, 5%, and 12% CO₂ atmospheres, each time for one, two, and four weeks. The control culture was maintained for one week without CO₂ atmosphere. Morphological changes were investigated and antifungal susceptibility test was performed according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI) M38-A2 document. The results of different CO₂ atmospheres were compared with that of the control sample.

Results

We found that 1%, 3%, 5%, and 12% CO₂ atmospheres were associated with morphological colony changes. Macroscopically, the colonies were shallow dark green, smooth, crisp to powdery with reduced growth; microscopic examination revealed the absence of conidiation. The induction of antifungal resistance in the susceptible strains to itraconazole, voriconazole, and amphotericin B increased after exposure to 12% CO₂ atmosphere and four weeks of incubation. The MIC values for itraconazole, voriconazole, and amphotericin B were 16 g/ml, 1 g/ml, and 16 g/ml, respectively. These values for the control group were 0.125 g/ml, 0.125 g/ml, and 2 g/ml, respectively.

Conclusion

Exposure to different CO₂ atmospheres induced morphological changes in A. fumigatus, it seems to increase the MIC values, as well. In parallel, resistance to both itraconazole and voriconazole was also observed.

Species identification and in vitro antifungal susceptibility testing of Aspergillus section Nigri strains isolated from otomycosis patients

INTRODUCTION

Aspergillus niger is the most commonly reported etiology of otomycosis based on morphological characteristics. This fungus is a member of Aspergillus section Nigri, a set of morphologically indistinguishable species that can harbor various antifungal susceptibility patterns. The aim of this study was to accurately identify and determine the susceptibility pattern of a set of black aspergilli isolated from otomycosis patients.

METHODS

Forty-three black Aspergillus isolates from otomycosis patients were identified by using the PCR-sequencing of the β-tubulin gene. Furthermore, the susceptibility of isolates to three antifungal drugs, including fluconazole (FLU), clotrimazole (CLT) and nystatin (NS), were tested according to CLSI M38-A2. The data were analyzed using the SPSS software (version 15).

RESULTS

The majority of isolates were identified as A. tubingensis (32/43, 74.42%) followed by A. niger (11/43, 25.58%). The lowest minimum inhibitory concentration (MIC) values were observed for NS with geometric means (GM) of 4.65μg/mL and 4.83μg/mL against A. tubingensis and A. niger isolates, respectively. CLT showed wide MIC ranges and a statistically significant inter-species difference was observed between A. tubingensis and A. niger isolates (P<0.05). FLU was inactive against both species with GMs>64μg/mL.

CONCLUSION

Species other than A. niger can be more frequent as observed in our study. In addition, considering the low and variable activity of tested antifungal drugs, empirical treatment can result in treatment failure. Accurate identification and antifungal susceptibility testing of isolates is, however, recommended.

Microsatellite genotyping of clinical Candida parapsilosis isolates

Background and Purpose:

Candida parapsilosis is a predominant species found in nosocomial infection, particularly in hospitalized patients. The molecular epidemiology of the clinical strains of this species has not been well studied. The present study was performed with the aim of investigating the microsatellite genotyping of Candida parapsilosis among the Iranian clinical isolates.

Materials and Methods:

This study was conducted on 81 independent clinical C. parapsilosis isolates that were genotyped by using a panel of six microsatellite markers.

Results:

The short tandem repeat (STR) typing of clinical C. parapsilosis isolates demonstrated 68 separate genotypes, among which 57 genotypes were observed once and the remaining 11 cases were identified for multiple times. The Simpson’s diversity index for the panel of combined six markers yielded a diversity index of 0.9951. The heterogeneity was observed among the Iranian and the Netherlands clinical C. parapsilosis isolates.

Conclusion:

As the findings indicated, the clinical C. parapsilosis isolates from Iran showed a high genetic diversity. It can be concluded that molecular epidemiology could be useful for screening during outbreak investigation where C. parapsilosis is involved.

Evaluation of PCR-reverse line blot hybridization assay for simultaneous identification of medically important saprophytic fungi

BACKGROUND

In immunocompromised patients suffering from invasive fungal infections, rapid identification of fungal species is important since the appropriate treatment is usually related to the responsible species. We describe here, an assay based on combination of PCR and reverse line blot hybridization (PCR/RLB) for differentiation causative agent of fungal infections.

MATERIALS AND METHODS

We performed PCR/RLB assay on 10 reference strains, which include Aspergillus species (A. fumigatus, A. flavus, A. niger, A. terreus, and A. clavatus), Mucor circnelloides, Rhizopus oryzae, Alternaria alternata, Cladosporium herbarum, and Fusarium solani. Besides, twenty-two clinical specimens from patients with proven fungal infections were analyzed for the identification of species. The obtained results were then compared with the results of culture and sequence analysis.

RESULTS

The fungal species-specific oligonucleotide probes were able to distinguish between all species represented in this study with the exception of cross-reactivity between A. niger and A. fumigatus species. Two specimens, which were represented as mixed fungi in culture, were identified properly by this method. Results of the RLB assay were concordant with the culture and ITS sequencing results.

CONCLUSION

Our result demonstrate that the RLB assay potentially is suitable for rapid and simultaneous identification of variety fungal pathogens directly from culture as well as from clinical specimens.

Regulation of ERG3, ERG6, and ERG11 Genes in Antifungal-Resistant isolates of Candida parapsilosis

Background

Candida parapsilosis is one of the five common strains of yeasts involved in invasive candidiasis. The expression analysis of sterol biosynthesis pathway genes, which are associated with resistance, can assist the better understanding of antifungal resistance mechanisms.

Method

The antifungal susceptibility of 120 clinical C. parapsilosis isolates was examined. The changes in the gene expression related to resistance were analyzed.

Results

Eight strains were resistant to fluconazole (FLC), itraconazole (ITC), and amphotericin B (AMB). The regulation variations included increased mRNA levels of ERG3, ERG6, and ERG11 and decreased mRNA levels of ERG3 and ERG6 in response to FLC. ERG11 mRNA level increases in response to ITC and AMB.

Conclusion

The mechanism of resistance to azoles in C. parapsilosis is very similar to C. Albicans. This feature may help to design new treatment strategy for candidiasis.

First case of superficial infection due to Naganishia albida (formerly Cryptococcus albidus) in Iran: A review of the literature

Background and Purpose:

Naganishia albida (formerly Cryptococcus albidus) is a non-neoformans cryptococcal species rarely isolated as a human pathogen.

Case report:

Herein, we present the case of a 26-year-old Iranian man with a superficial cutaneous lesion in the axilla. The initial treatment for pityriasis versicolor by clotrimazole was unsuccessful. We performed skin sampling based on the standard protocol and conducted further investigations by the conventional laboratory tests and molecular analysis of the skin samples. All the mentioned analyses revealed N.albida as the causative agent of infection. The minimum inhibitory concentration (MIC) analysis was carried out for the isolated agent, and the patient was treated using 100 mg daily of oral itraconazole.

Conclusion:

N. albida can be the causative agent of some superficial infections. This is the first report on the successful detection and treatment of a superficial skin infection due to N. albida by oral itraconazole.

Pseudohyphae formation in Candida glabrata due to CO2 exposure

BACKGROUND AND PURPOSE

Formation of pseudohyphae is considered a virulence factor in Candida species. Generally, Candida glabrata grows as budding yeast cells; however, reports illustrated that C. glabrata could form pseudohyphal cells in response to some stimuli. In this study, we provided insight into the ability of C. glabrata in forming pseudohyphal cells under different levels of carbon dioxide (CO₂).

MATERIALS AND METHODS

Candida glabrata reference strain (ATCC 90030) was used in this study. Yeast samples were cultured on Sabouraud dextrose broth (SDB) medium and incubated under 3%, 5%, and 10% CO₂ levels for 24, 48 and 72 h. Control cultures were prepared without CO₂ pressure for three days. The possibility of pseudohyphae and mycelium formation in C. glabrata was investigated.

RESULTS

The results of this study revealed that the most branching filament-like cells were obtained at high CO₂ pressure (10%) after 72 h. After three days of low CO₂ pressure (3%), only yeast and budding cells were observed without any pseudohyphae formation.

CONCLUSION

CO₂ could act as a stimulus and induced formation of pseudohyphae in Candida glabrata yeast cells.

Expression of Efflux Pumps and Fatty Acid Activator One Genes in Azole Resistant Candida Glabrata Isolated From Immunocompromised Patients

Acquired azole resistance in opportunistic fungi causes severe clinical problems in immunosuppressed individuals. This study investigated the molecular mechanisms of azole resistance in clinical isolates of Candida glabrata. Six unmatched strains were obtained from an epidemiological survey of candidiasis in immunocompromised hosts that included azole and amphotericin B susceptible and azole resistant clinical isolates. Candida glabrata CBS 138 was used as reference strain. Antifungal susceptibility testing of clinical isolates was evaluated using Clinical and Laboratory Standards Institute (CLSI) methods. Complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) technology, semi-quantitative RT-PCR, and sequencing were employed for identification of potential genes involved in azole resistance. Candida glabrata Candida drug resistance 1 (CgCDR1) and Candida glabrata Candida drug resistance 2 (CgCDR2) genes, which encode for multidrug transporters, were found to be upregulated in azole-resistant isolates (≥2-fold). Fatty acid activator 1 (FAA1) gene, belonging to Acyl-CoA synthetases, showed expression in resistant isolates ≥2-fold that of the susceptible isolates and the reference strain. This study revealed overexpression of the CgCDR1, CgCDR2, and FAA1 genes affecting biological pathways, small hydrophobic compounds transport, and lipid metabolism in the resistant clinical C.glabrata isolates.