Iranian Journal of Microbiology
Volume:14 Issue: 1, Feb 2022

Coronavirus Disease 2019 (COVID-19) is a pandemic disease caused by a new corona virus. COVID-19 affects different people in different ways. COVID-19 could affect the gastrointestinal system via gut microbiota impairment. Gut microbiota could affect lung health through a relationship between gut and lung microbiota, which is named gut-lung axis. Gut microbiota impairment plays a role in pathogenesis of various pulmonary disease states, so GI diseases were found to be associated with respiratory diseases. Moreover, most infected people will develop mild to moderate gastrointestinal (GI) symptoms such as diarrhea, vomiting, and stomachache, which is caused by impairment in gut microbiota. Therefore, the current study aimed to review potential role of gut microbiota in patients with COVID-19, its relation with lung axis, Central Nervous System (CNS) axis and improvement with probiotic therapy. Also, this review can be a guide for potential role of gut microbiota in patients with COVID-19.

Since the COVID-19 pandemic initiation, more than 28 million elective surgeries were postponed with a cancellation rate of 72.3%. However, studies suggested that the patient treatment should be conducted within 12 weeks of diagnosis because delay in treatment might have had adverse impacts on patients' health status, prognosis, and pathologic stage. Hence, the current study aimed to assess the importance of a pre-operative COVID-19 screening test for the patients were candidates for elective surgery.

This cross-sectional study was conducted on 141 patients who were candidates for any type of elective surgeries or cesarean section at a tertiary university-based hospital, between June 2020, and September 2020.

The mean age of participants was 41.38 ± 11.66 years. Of them, 91.5% were women and 8.5% were men. The COVID-19 polymerase chain reaction (PCR) screening tests were positive in 12 (8.5%) patients. From whose PCR tests were positive, only five people (less than half) had symptoms of COVID-19 such as fever (three patients), a distinctive smell (two patients), and cough (one patient). Suspected exposure to COVID-19 was reported in four of them.

In this study, we found that more than half of PCR positive COVID-19 patients were asymptomatic. Therefore, to have a safe hospital environment, and improve patient health outcomes, the COVID-19 screening test should be applied before any interventions.

Measures to prevent the emergence of hospital-acquired infections (HAIs) include a daily bath with chlorhexidine gluconate (CHG). The aim of this study was to determine the effect of patients bathing daily with CHG on the bacterial colonization on patient surfaces, environmental surrounding areas, and attending healthcare workers (HCWs).

Patients were randomized by a 1:1 in two groups. Patients in group 1 were bathed daily with CHG; patients in group 2 were bathed with a placebo. Microbiological sampling of patients, environment, and HCWs were carried out on days 0, 3, and 10. The clonal relatedness of selected isolates collected was determined through pulsed-field gel electrophoresis. Clinical and demographic data were obtained from medical files.

Thirty-three patients were included (18 in group 1 and 15 in group 2). The more common species was Acinetobacter baumannii (n=144), followed by Klebsiella pneumoniae (n=81). A. baumannii was isolated more frequently on environmental surfaces in group 2 than group 1 (day 0 vs. day 3 vs. day 10; p = 0.0388). Twelve clones of A. baumannii were detected, with predominant clone A detected in patients and environmental surfaces. No pathogens were detected in HCWs.

Our data support that CHG bathing decreases A. baumannii surviving on the environmental surfaces of critically ill patients.

Anaerobic bacteria are a common cause of endogenous infections, some of which can be life threatening. These bacteria are not easily cultured and isolated and often cannot even found from infected sites. Delayed or inappropriate treatment of these microorganisms can lead to failure in eradicating these infections. The purpose of this study was to determine the diversity of anaerobic bacteria at present and their pattern of sensitivity to several antibiotics.

A retrospective study was conducted over a period of two years on various specimens. Specimens derived from body fluids are inoculated on a BacT/Alert (bioMérieux). Anaerobic isolates were identified by Gram staining and continued identification using Vitek 2® automated system. Antibiotic sensitivity examination was carried out using ATBTM ANA (bioMérieux).

A total of 440 specimens were received in microbiology laboratory for anaerobic culture from patients with multiple infections from 13 hospitals in Jakarta. Our research was able to identify 18 species on anaerobic bacteria, consisting 52.5% Gram positive and 47.5% Gram negative bacteria. The most common bacteria found were Clostridium perfringens (15%) from Gram positive and Provetella bivia (10%) from Gram negative. The sensitivity pattern shows that antibiotic piperacilline-tazobactam is 100% effective against anaerobic bacteria, while metronidazole as the drug of choice is only 75% effective. Against Gram positive, several antibiotics such as piperacilline-tazobactam, ticarcilin-clavunic acid, cefoxitin, cefotetan, imipenem and chloramphenicol were 100% effective, however metronidazole occupied the lowest position (61.9%). Meanwhile against Gram negative antibiotics piperacilline-tazobactam is 100% effective and chloramphenicol in the second position (94.75%).

Clostridium perfringens and Provetella bivia are the most common bacteria found. The antibiotics piperacilline-tazobactam is 100% effective against both Gram positive and negative. The accuracy of specimen management, isolation, identification and sensitivity examination will determine the successful microbiological investigations.

One of the major causes of urinary tract infections is Klebsiella pneumoniae. Currently, few studies investigated the mechanisms of resistance to colistin in Iran. The current study aimed to determine the prevalence of plasmid and chromosome-mediated resistance to colistin in K. pneumoniae isolates.

177 urine samples were collected from patients with urinary tract infections hospitalized in the intensive care unit (ICU) of hospitals in the city of Qazvin. K. pneumoniae isolates were identified by standard biochemical methods, resistance to colistin among K. pneumoniae isolates were tested by disk diffusion and microbroth dilution methods. The chromosomal mutation and presence of the mcr genes in colistin-resistant K. pneumoniae were evaluated by PCR.

Out of 177 samples, 65 K. pneumoniae were obtained from patients in the ICU. Six colistin-resistant isolates were isolated with MIC values ≥4 μg/mL, none of them was positive for mcr1-5. In 4 isolates, missense mutation in mgrB gene resulted in amino acid substitutions and in one isolate of mgrB gene was found intact mgrB gene.

The results suggest that mgrB mutation was the main mutation among colistin-resistant isolates and plasmid-borne colistin resistance was not expanded among strains.

Emerging of carbapenem-resistant Klebsiella pneumoniae (CRKP) is one of the major concerns among healthcare systems. This study aimed to investigate the antibiotic susceptibility pattern and carbapenemase genes of carbapenemase-producing K. pneumoniae isolates obtained from Iranian hospitalized patients.

This study was performed on 71 CRKP strains isolated from different clinical specimens collected in Tehran Heart Center (Tehran, Iran). A Modified Hodge test (MHT) was done for the detection of carbapenemase-producing K. pneumoniae. The presence of blaKPC, blaVIM, blaIMP, blaNDM, and blaOXA-48-type carbapenemases was evaluated by the PCR method.

We identified 8.82% (71/805) of K. pneumoniae isolates as CRKP by MHT test. The antibiotic susceptibility indicated that all isolates were resistant to imipenem, meropenem, cefotaxime, ceftazidime, cefepime, ceftriaxone, cephalothin, ciprofloxacin, and augmentin, and then mostly resistant to aztreonam, cefoxitin, gentamicin, and trimethoprim/sulfamethoxazole with 98.6%, 98.6%, 97.2%, and 94.4%, respectively. The lowest resistance was related to amikacin with 46.5% (33/71 isolates). The level of imipenem MIC for all carbapenem-resistant isolates was estimated ≥32 µg/mL. Among positive isolates for carbapenemase genes, the most frequent gene was blaOXA-48. It was found in 48 (67.6%) isolates followed by blaVIM in 28 (39.4%) isolates. blaIMP, blaNDM, and blaKPC genes were identified in 19 (26.8%), 13 (18.3%) and 5 (7.0%) isolates, respectively. These genes were not detected in nine isolates.

The relatively high frequency of some carbapenemase genes suggests major concern about the emergence of isolates containing carbapenem resistance genes as a potential health threat.

Streptococcus pneumonia (S. pneumoniae) is one of the most frequent pathogens leading to a variety of clinical manifestations. The effects of S. pneumoniae carriage on acute otitis media (AOM) are poorly studied. The study aimed to assess the serotype’s distribution and antimicrobial susceptibility in children with AOM after the implementation of the pneumococcal conjugate vaccine (PCV) in Morocco.

We conducted a prospective study of AOM children aged 6 to 36 months who visited pediatric centers in Marrakesh between January to June 2018. Parents were asked to complete a questionnaire and a swab was collected from each child. The S. pneumoniae strains were further identified (Hemolysis, optochin sensitivity, and agglutination test), serogrouped (IMMULEX PNEUMOTEST agglutination test), serotyped (Real time PCR) and tested for antimicrobial susceptibility.

The S. pneumoniae carriage rate was 49.7% (87/175). As estimated, non-vaccine serotypes (NVT) were most prevalent (51/63; 81%). The most frequent serotypes were 6C/6D (12.7%), 10 (9.5%), and 19B/19C (9.5%). The S. pneumoniae strains that were isolated showed a diminished susceptibility to penicillin G with a rate of 27.5%. Penicillin non-susceptible pneumococci (PNSP) was mostly associated with NVT. More than 90% of S. pneumoniae isolates were susceptible to chloramphenicol (97.5%), clindamycin (97.5%), erythromycin (97.5%), levofloxacin (97.5%), pristinamycin (97.5%), gentamicin (92.5%), and teicoplanin (92.5%).

Important nasopharyngeal carriage prevalence was reported among children with AOM. The study showed that new NVT are emerging, including 6C/6D and 10. Furthermore, susceptibility was significantly higher against all antibiotics tested except for penicillin G and amoxicillin.

MRSA became a widely recognized cause of mortality worldwide with necessity of its epidemiological pattern study. Typing of MRSA isolates was performed molecularly based on SCCmec type and relation to resistance pattern was investigated.

Out of 200 clinical specimens, S. aureus was detected phenotypically and confirmed as MRSA by PCR in 124 isolates obtained from associated laboratories of different hospitals of Zagazig, during 2018-2019. Antimicrobial resistance pattern was detected and MRSA SCCmec was typed by two methods.

S. aureus rate was high in wounds, sputum, blood, and urine isolates. Antimicrobial resistance rates against cefotaxime, tetracycline, gentamicin, ciprofloxacin, erythromycin, azithromycin, clindamycin, chloramphenicol, sulfamethoxazole-trimethoprim, linezolid and vancomycin were 82.3%, 65.3%, 56.4%, 45.1%, 37.1%, 32.3%, 32.3%, 25%, 7.3%, 2.4% and 0%, respectively. Multiplex-PCR(M-PCR ) was able to detect SCCmec element among 57% of isolates classified as SCCmec II (n=40), III (n=21), IVa (n=3), IVd (n=2), V(n=1), and four isolates contain both SCCmec ІІ and SCCmec ІV. Traditional typing by PCR for mec and ccr gene complexes was almost concordant with M-PCR. Furthermore, it was able to identify SCCmec types VI, IX, and XIV among 1, 3 and 18 isolates, respectively. No Statistical correlation was established between type of cassette and rate of antimicrobial resistance. Phylogenetic analysis reveals that all ccr types were related to each other and no significant variation in the same ccr type of different SCCmec cassettes.

Most MRSA isolates were MDR reflecting antimicrobials misuse. Detection of various SCCmec types among MRSA isolates indictae the complexity of MRSA epidemiology and increase chance for gene sharing creating new types.The presented investigation was important in understanding MRSA epidemiology and diversity in Egypt providing advice for improving therapeutic protocols.

The ever-increasing of antibiotic resistance in methicillin-resistant Staphylococcus aureus (MRSA) has become a major threat to public health worldwide. Molecular typing is used to determine the source of MRSA infections as well as to control and prevent the spread of these pathogens. The present study aimed to investigate the characteristics of staphylococcal cassette chromosome mec (SCCmec) types and antibiotic resistance of community- acquired (CA-) and hospital acquired (HA-) MRSA isolates.

In this cross-sectional study, the antibiotic susceptibility patterns of 109 clinical S. aureus isolates were determined by the Kirby-Bauer disk-diffusion and microdilution broth methods. MRSA isolates were confirmed using the polymerase chain reaction (PCR) method for the detection of the mecA gene. SCCmec typing was performed by a multiplex PCR assay among MRSA isolates.

The prevalence of MRSA isolates was 39.4%. Linezolid, vancomycin, and ceftaroline were the most effective agents against MRSA isolates. The incidence of multidrug-resistant (MDR) and resistance to most antibiotics were significantly higher in MRSA than methicillin-susceptible S. aureus (MSSA) isolates (P<0.05). SCCmec types I, III, and IV were identified in 27.9%, 23.3%, and 37.2% of MRSA isolates, respectively. SCCmec type I and IV were the most prevalent SCCmec types in HA-MRSA isolates (each was 32.4%). While SCCmec type IV (66.7%) was the most frequently SCCmec type associated with CA-MRSA isolates.

Our findings demonstrated a high rate of MDR among MRSA isolates. The high existence of SCCmec type IV was reported among the HA-MRSA isolates, which can indicate the spread of MRSA community isolates to hospital settings. Therefore, appropriate antibiotic stewardship plans and microbiological surveillance initiatives must be implemented in healthcare facilities to monitor and limit the spread of these resistant bugs.

Staphylococcus aureus is one of the most common causes of food poisoning. This study aimed to identify S. aureus isolated from pastries, the virulence factors, antimicrobial resistance patterns, biofilm formation, and then classification based on SCCmec types, phage types, and also Rep types.

In this study, 370 creamy and dried pastry samples have been randomly collected from different confectioneries in Hamadan city. The S. aureus isolates were identified by conventional microbiological methods and nuc gene amplification. The virulence factors and prophage genes were detected. After that, the biofilm production and antibiotic susceptibility assay of S. aureus isolates were examined. Finally, the isolates were classified by rep-PCR typing.

Among 370 samples, 97 creamy (34.64%) and 3 dried (3.33%) pastry samples were contaminated with S. aureus. Antibiotic sensitivity results showed the highest resistance to penicillin (90%) but none of them were MRSA. According to biofilm formation assay, 14 strains (45%) were strongly adhesive. The dominant phage among isolates was SGF, especially SGFa subgroup. About half of the isolates carried SCCmec Types I and III. Analysis of the genetic linkage between isolates by rep-PCR showed ≥80% genetic similarity and also different rep-types of S. aureus isolates.

The presence of different prophage encoded virulence factors and antibiotic resistance enable S. aureus strains to produce a broad range of diseases. Thus, consumption of creamy pastries increases the risk of infection with S. aureus and it is a serious warning to the health system.

Pathogenic diseases resulting from microbial contamination of food have been widely distributed in many parts of the world. Among these, Escherichia coli is one of the most important foodborne pathogenic bacteria. Diarrhea is one of the major causes of children’s death in developing countries, with approximately 2 million deaths annually. The current study aimed to determine the frequency of diarrheagenic E. coli pathotypes such as Enteropathogenic E. coli (EPEC), Enterotoxigenic E. coli (ETEC), Enteroaggregative E. coli (EAEC), and Shiga toxin-producing E. coli (STEC) in Brassica oleracea cultivars in order to provide information on the assessment of diarrheagenic E. coli pathogenesis risk.

100 samples of vegetables were collected in Tehran, including cabbage, cauliflower, broccoli and Brussels sprouts. After homogenizing samples, enrichment was done in the EC broth medium. Five colonies of pure culture were used for DNA extraction. Pathotypes were identified by PCR using virulence genes.

The results showed that the prevalence of diarrheagenic E. coli strains was 7%. The EPEC prevalence was 3%, All EPEC isolates were atypical. The ETEC frequency was 3%, And the EAEC prevalence was 1%.

These findings indicated that Brassica oleracea cultivars could be consideredas a source of contamination with diarrhea-causing E. coli strains.

Almost all living cells secret nano-sized structures enclosed by the lipid bilayer called extracellular vesicles (EVs) into their extracellular milieu. These EVs play important roles in several physiological processes as a cargo delivery system. In probiotics, EVs are the main communication tool with the host. The present study aimed to assess the effect of EVs originated from Lactobacillus rhamnosus GG on the Carcinoembryonic antigen (cea) gene expression and protein (CEA) synthesis in the SW480 and HT-29 cell lines.

Different concentrations of Lactobacillus rhamnosus GG EVs were applied on the SW480 and HT-29 cell lines. The MTT assay, Real-Time PCR, and ELISA analysis methods were exploited to explore the cell viability and the expression level of the cea gene in comparison with the β-actin gene as the control.

The two concentrations of 80 and 100 μg/ml of Lactobacillus rhamnosus GG EVs considerably affected the anti-proliferation and increased the amount of both CEA mRNA and protein (p < 0.05).

Our findings showed that EVs of Lactobacillus rhamnosus GG could induce the gene expression and protein synthesis of CEA. Also, they reduced the cell proliferation of HT29 and SW480. Thus, probiotics such as EVs of Lactobacillus rhamnosus GG could be useful for preventing colorectal cancer.

Medicinal plants have recently received much interest because of the low production costs and fewer side effects associated with remedies made from them compared with chemical therapies. The current study investigated the antioxidant, antibacterial, and cytotoxicity properties of an ethanol extract of Cordiamyxa fruit (CMF) extract.

The antioxidant activity of CMF was determined by measuring electron-donating ability with a 1,1-diphenyl-2picrylhydrazyl (DPPH) assay. The phenolic content was calculated as Gallic acid equivalents using the Folin–Ciocalteu assay. To evaluate the efficiency of CMF, five multidrug-resistant bacterial strains (Salmonella enterica, Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa) were tested using the agar diffusion method. Furthermore, the cytotoxic activity of CMF was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-dipheltetrazolium (MTT) assay against a healthy fibroblast (L929) cell line.

The CMF ethanol extract was revealed to have substantial phenol and flavonoid content (113.71± 0.04 mg gallic acid/g dried extract and 68.9 ± 0.002 mg quercetin/g dried extract, respectively) that showed the highest percentage of DPPH inhibition (86.45%), which was achieved by ethanol extract at the concentration of 60 μg/ml,with excellent antibacterial activity against S. aureus, E. coli, S. enterica, B. subtilis, and P. aeruginosa (17.5 ± 1.0, 14.9 ± 1.0, 13.3 ± 1.5, 15.7 ± 1.0, and 13.8 ± 1.5 mm IZ, respectively). In addition, no expressive antiproliferative effect was recorded in the assessment of cytotoxicity on L929 cells.

According to the current findings, CMF exhibits low cytotoxicity, antibacterial activity, and antioxidant properties in vitro and can be developed for pharmaceutical and medical uses in the future.

In recent decades, the incidence of dengue has increased dramatically. In dengue-endemic countries, changes in dengue virus serotypes, genotypes, and lineages have been reported. This study was designed to detect and characterize the dengue virus isolates circulating in North India by serological and molecular techniques.

This study was conducted at the Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India. NS1 antigen and IgM antibody against dengue were detected by ELISA methods, viral RNA was extracted and amplified by conventional PCR and one-step single-tube multiplex PCR. The purified PCR products were cycle sequenced and a database search was implemented for the confirmation of the sequence product. Phylogenetic analysis was carried out with previously reported sequences.

Among 1509 samples, 205 (13.6%) were found positive for IgM antibodies with the highest number (n=67) among the 21 to 30 years age group with peak positivity during post-monsoon months. Among acute samples, NS1 antigen was positive in 62.9%. Seven patients out of 13 had dengue viral RNA in PCR. It comprised six DENV-2 serotypes and one DENV-3 serotype. On phylogenetic analysis, DENV-2 strains grouped with genotype IV and DENV-3 with genotype III.

Dengue infection was found frequently during post-monsoon season. The positivity rate of the dengue NS1 antigen test was greater than that of the antibody test. The dengue isolates were characterized as genotype IV and genotype III of DENV-2 and DENV-3 respectively.

The human papillomavirus (HPV) is associated with more than 70% of the cervical neoplasm. The current study aims to evaluate the distribution of HPV genotypes in suspected women cytological specimens from Tehran, Iran.

In the current cross-sectional study, HPV genotype prevalence was investigated in 433 subject women. DNA extraction was performed by High Pure Viral Nucleic Acid kit. A semi-automatically hybriSpot 24™ (HS24) setting was used for HPV typing and data interpreted by hybriSoft™ software according to instructions.

Pathologic data showed 181 (41.8%) had non-malignant lesions, 212 (49%) had inflammation and 40 (9.2%) reported LSIL in primary Pap-smear result. HPV was found in 143 (33%) specimens and the most comment high-risk and low-risk HPV types were HPV-16 and -6, respectively. Also, 62 (43%) were co-infected with multiple genotypes includes, 34 (24%) cases had co-infection with two HPV types, 17 (12%) cases had co-infection with three HPV types, 6 (4%) cases had co-infection with four HPV types and 5 (3%) cases had co-infection with five HPV types. There was statistically different domination on high-risk genotype in most of the co-infected samples (p<0.01).

Current study indicates that the lesion pathology assessment was significantly associated with the HPV infection (p<0.01). Furthermore, the age group assessment shows that most of the HPV positive cases were 21 to 40 (p<0.01). The HPV infection prevalence in the current study was 33% and the most frequently reported high-risk and low-risk HPV types were 16 and 6, respectively.

Umbilical cord blood (UCB) was used to source hematopoietic stem cells in the past. Despite the apparent advantages of UCB transplantation, virus reactivation poses a considerable danger in allogeneic hematopoietic stem cell transplantation (HSCT). Human Parvovirus B19 is regarded as a potential threat to UCB contamination. This study aimed to evaluate the prevalence of parvovirus B19 in cord blood donors by Semi-Nested PCR. This study is the first large-scale report of the B19 DNA in cord blood donors in Iran.

A total of 691 umbilical cord blood were collected under standard procedure. Then, DNA from buffy coat and plasma were extracted, and semi-nested PCR was performed for all samples.

Two out of 691 samples (0.29%) indicated viremia in plasma and buffy coat.

In this line, designing and validating a quantitative PCR assay for detection, quantification, and discrimination of Human B19 DNA genotypes of cord blood donors is necessary to enhance the safety of this source of stem cells.

Human T-lymphotropic virus type 1 (HTLV-1) is the cause of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The present study aims to analyze gene expression patterns in ATL and HAM/TSP.

Microarray gene expression profiling of T-lymphocytes from HTLV-1 associated disease and healthy control were obtained from Gene Expression Omnibus (GEO). Several bioinformatics tools were used to identify differentially expressed genes (DEGs). Among the generated DEGs, we constructed protein-protein interaction (PPI) between HAM/TSM and ATL in comparison to asymptomatic carriers (ACs). Subsequently, gene ontology (GO) and topological analysis were performed.

We found that the majority of DEGs in ATL and HAM/TSP were importantly implicated in immune response categories. The nodes and edges number of normal-AC, AC-ATL and ATL-HAM/TSP PPIs were 168 and 145, 116 and 97, and 275 and 327, respectively. Based on the topological analyses of protein-protein interaction networks, APP (Amyloid Beta Precursor Protein) was detected as a critical player in progression of HTLV-1 disease.

Dysregulation of immune response associated transcripts play a critical role in HTLV-1 disease progression. Immune response associated genes may be biomarker for prognosis in cancer development and therapeutic targets.

Catalases are a good scavenger of H2O2 which degrades hydrogen peroxide into water and oxygen. They are considered as a virulence factor that are present in both spores and hypha of fungi. There is limited data regarding catalase activity in Aspergillus species. This study aimed to assess the mycelial catalase activity of clinical and environmental isolates of Aspergillus niger, A. tubingensis, A. flavus, A. luchuensis, A. piperis and A. terreus.

Briefly, clinical and environmental Aspergillus species were used in the current study. Catalase activity was assessed for both groups of isolates including 13 A. flavus (12 clinical, 1 environmental), 13 A. terreus (8 clinical, 5 environmental), 26 A. tubingensis (13 clinical, 13 environmental), and 44 A. niger (25 environmental, 19 clinical) species. Fungal balls of mycelia were separated from the liquid culture and were crushed using homogenizer. The supernatants were collected and used for a catalase activity assay.

Totally, in our study 98 Aspergillus including 45 environmental and 53 clinical isolates were assessed for catalase activity. High catalase activity was detected among environmental Aspergillus species (Mean= 1.62 mU/ml) and the mean of mycelial catalase activity among clinical A. terreus isolates was higher than environmental strains.

In summary, mycelial catalase activity varied among species and environmental isolates demonstrated higher catalase activity. Totally a significant difference was found between clinical and environmental Aspergillus isolates.