Iranian Journal of Microbiology

Revealing COVID-19 breakthrough infection rates among vaccinated individuals at a tertiary care centre in South India

Sat, 05 Apr 2025 09:54:15 +0430

Background and Objectives: The COVID-19 pandemic was mitigated by the rapid development and deployment of vaccines. While vaccines reduce infection severity, breakthrough infections (BTIs) still occur. The CDC defines BTI as a positive SARS-CoV-2 test ≥14 days post-vaccination. This study investigates the occurrence of COVID-19 BTIs at a tertiary care hospital in Puducherry, South India.
Materials and Methods: This retrospective study analysed hospital tested qRT-PCR data of individuals from the ICMR portal (March 2021–March 2022). Demographic and vaccination details were extracted.
Results: Among 8001 tested individuals, 1452 were vaccinated. The BTI rate decreased from 16.6% to 1.2% after the first dose and from 58% to 40% after the second one. Odds ratio indicated a 74% reduction in infection risk for vaccinated individuals compared to unvaccinated. Males had higher infection rates than females, regardless of vaccination status.
Conclusion: Our study demonstrates a higher BTI rate after one vaccine dose compared to two doses. The BTI rate also increased four months post-vaccination, even with two doses, potentially due to waning immunity and the emergence of new variants. Therefore, continued adherence to preventive measures in conjunction with vaccination is crucial for minimizing COVID-19 transmission.

Design and assessment of a multiplex real-time PCR method for simultaneous detection and differentiation of COVID-19 and Influenza A/B

Nafiseh Fotros, Reihaneh Bashiri, Samira Mohammadi-Yeganeh, Mahdi Paryan — Sat, 05 Apr 2025 09:56:52 +0430

Background and Objectives: Viral infections of the respiratory system are a major public problem due to their ease of spread, pandemic potential, and significant rate of death. Diagnosing these infections requires laboratory testing, as clinical symptoms alone are often insufficient. Influenza A, Influenza B, and COVID-19 are common infections that burden the population, especially during winter. We developed a multiplex real-time PCR method to simultaneously detect Influenza A and B, as well as COVID-19. Compared to existing detection kits, it offers higher accuracy, lower costs, and faster results, making it an efficient diagnostic tool.
Materials and Methods: We designed primer/TaqMan probes for the M2 gene of Influenza A, N gene of SARS-CoV-2, and NS1 gene of Influenza B. Reaction components were optimized and functional parameters were tested using standard samples with known viral copy numbers.
Results: The method’s detection limit is 10 copies for Influenza A and B, and 60 for SARS-CoV-2. Sensitivity and specificity for Influenza A are 88% and 100%, for Influenza B, 95.6% and 100%, and for SARS-CoV-2, 90.4% and 100%.
Conclusion: This multiplex real-time PCR method can accurately detect and distinguish SARS-CoV-2, Influenza B, and Influenza A infections.

Insights into global transcriptomic profile of biofilm producing Staphylococcus aureus clinical isolates from chronic foot ulcers

Kumar Ebineshan, Aparna Srikantam, Michael Sukumar Pallapati — Sat, 05 Apr 2025 10:00:01 +0430

Background and Objectives: Staphylococcus aureus (S. aureus) is one of the predominant biofilm producing pathogen in leprosy foot ulcer (LFU). The objective of this study was to identify the transcriptome profile through Next Generation Sequencing (NGS) approach in mature biofilm of leprosy foot ulcer isolate of S. aureus.
Materials and Methods: A cross-sectional study was conducted from July 2019 to May 2022 and a total of twenty-seven S. aureus isolates were collected from the foot ulcers of leprosy patients. All S. aureus isolates were screened for biofilm formation in vitro. Initially, two potential biofilm producing isolates and two planktonic cells were selected for transcriptome comparison.
Results: With reference to transcriptome profile, out of 2,842 genes, 2,688 genes in mature biofilm and 2,685 genes in planktonic cells were expressed. Among them, forty-five differentially expressed genes with 32 and 13 genes showing up and down regulation respectively were obtained.
Conclusion: The research emphasizes the need for continued exploration into the mechanisms of biofilm formation by S. aureus, particularly in the context of leprosy foot ulcers. Understanding these pathways not only aids in grasping the complexity of chronic infections but also paves the way for innovative therapeutic approaches aimed at mitigating biofilm-related complications in clinical settings.

Protective effects of Staphylococcal Enterotoxin B (SEB) toxoid on lung and liver tissue integrity in rats during systemic infection

Dhafer Rasheed Al-Fetly, Atiaf Ghanim Rhyaf, Hala Abbas Naji — Sat, 05 Apr 2025 10:01:23 +0430

Background and Objectives: Staphylococcal enterotoxin B (SEB), a potent superantigenic toxin produced by Staphylococcus aureus (S. aureus), plays a crucial role in S. aureus systemic infection. This investigation sought to determine whether immunising animals with SEB toxoid could protect against an experimental acute systemic infection caused by S. aureus.
Materials and Methods: This study involved three groups of animals: one group was administered with SEB toxoid, and the second group was administered with intramuscular injections of normal saline, after which both were subjected to systemic S. aureus infection. The third group served as the negative control. After two weeks, the outcomes of the experimental systemic infection demonstrated that SEB immunisation significantly shielded organs (lung and liver) from damage in comparison to the control group.
Results: Regarding the histopathological analysis of liver and lung tissues, the control group showed minimal alterations, indicating a normal tissue state. Infected individuals exhibited severe pathology, including inflammation, necrosis, and fibrosis. The immunised group displayed a mixed profile with elevated inflammation but lower necrosis and fibrosis. Immunisation mitigated pathological changes induced by infection, fostering a more controlled response.
Conclusion: SEB plays an important role in S. aureus pathogenesis and immunisation, and this toxoid might protect against fatal infections of S. aureus.

Resistance profiles of Staphylococcus aureus isolates against frequently used antibiotics at private sector laboratories in Jordan

Sat, 05 Apr 2025 10:02:20 +0430

Background and Objectives: Staphylococcus aureus (S. aureus) is one of the most important pathogens, responsible for a range of infections. This study aimed to assess resistance patterns in S. aureus isolates obtained from certain private-sector laboratories against commonly used antimicrobial agents.
Materials and Methods: The process involved collecting various samples from several private laboratories and then identifying S. aureus isolates using biochemical characterization. The antibiotic susceptibility of these isolates was determined by disc diffusion method . Furthermore, Rt-PCR was employed to identify two genes namely the methicillin/oxacillin resistance genes (mecA), and (SCCmec).
Results: The findings of the current study exhibited that females constituted a larger proportion of the participants (59.1%) compared to males (40.9%), with a mean participant age of 40.82 years. Gram-positive bacteria were more prevalent (71.3%) than Gram-negative bacteria (18.3%), with S. aureus being the most frequent isolate (60.9%). Urine samples represented the highest collected sample type (47.8%). Out of the 115 bacterial isolates, 85.2% exhibited multidrug resistance to antibiotics such as cefazolin, gentamicin, vancomycin, and ceftazidime. Clindamycin was the most effective antibiotic, with a sensitivity rate of 62.9%, followed by teicoplanin and meropenem, each with a sensitivity rate of 52.9%. Methicillin-resistant Staphylococcus aureus (MRSA) strains were susceptabile to vancomycin and teicoplanin. The methicillin/oxacillin resistant isolates showed significant association with mecA and SCCA genes.
Conclusion: This study highlighted the multi-drug resistance in S. aureus isolates, stressing the need for stringent antibiotic stewardship, continuous surveillance, and further research into alternative treatments, including novel antibiotics and combination therapy, to combat resistant strains.

Identification and antimicrobial susceptibility testing of Streptococcus agalactiae associated urinary tract infections using VITEK 2 system

Parviz Mohajeri, Hossein Faridafshar, Sara Kooti — Sat, 05 Apr 2025 10:03:03 +0430

Background and Objectives: As a Gram-positive bacterium, Streptococcus agalactiae or Group B Streptococcus (GBS) is normally found as a transient flora of the gastrointestinal and genitourinary tracts of women. The high prevalence of GBS in the urethra warrants investigation of UTIs and antibiotic resistance frequency associated with GBS. Given the paucity of research on antibiotic resistance of GBS in Iran, the present study investigated the UTIs associated with GBS and the antibiotic susceptibility patterns associated with GBS.
Materials and Methods: This study included 65 GBS strains collected from urine samples obtained from the Bouali Laboratory Complex, one of the largest laboratories in western Iran. VITEK 2 GP ID cards were used to identify all GBS isolates. VITEK 2 susceptibility testing for Gram-positive bacteria was performed according to the manufacturer's instructions using the AST-ST card. MIC method was performed after the detection of GBS strains.
Results: We found that 53 (81.5%) of the GBS isolates showed resistance to tetracycline; 47 (72.3%), 40 (61.5%), and 30 (46.15%) of these had a resistance to erythromycin, clindamycin and ampicillin respectively.
Conclusion: In the present study, the VITEK 2 system was validated as a user-friendly system that can serve as a rapid and accurate tool for identification and antimicrobial susceptibility testing of GBS.

Activity of cefiderocol on extensively drug-resistant Pseudomonas aeruginosa from burn wound infections in Mansoura, Egypt

Rasha El-Mahdy, Ahmed Mostafa, Nora El-Tantawy, Raghdaa Shrief — Sat, 05 Apr 2025 10:03:41 +0430

Background and Objectives: Increased Pseudomonas aeruginosa antibiotic resistance limits treatment options and is associated with a higher level of mortality and mordacity. The purpose of this research was to identify class 1 and 2 integrons, carbapenemase, SHV, and TEM genes in extensively drug-resistant (XDR) P. aeruginosa isolated from infected burns and evaluate their in vitro cefiderocol activity.
Materials and Methods: By using the disc diffusion method, the antimicrobial susceptibility of 110 P. aeruginosa isolates collected from infected burns were evaluated. XDR P. aeruginosa were screened phenotypically for carbapenemase and extended spectrum β-lactamases (ESBLs) production. Both MIC Test Strip and disc diffusion were employed to test the cefiderocol susceptibility. PCR was used to assess carbapenemase, SHV and TEM genes and integrons class 1 and 2.
Results: From the 110 P. aeruginosa, 54 isolates (49%) were XDR. TEM gene was detected in 35 isolates. Among XDR isolates, carbapenemase genes were detected in 31.5%, with NDM being predominant Thirty XDR isolates had class1 integrons. All isolates were sensitive to cefiderocol and its MIC₅₀/MIC₉₀ was 0.5/1.5mg/L (range 0.064-1.5mg/L).
Conclusion: Nearly half the P. aeruginosa isolates from burn infections were extensively drug-resistant. Cefiderocol's in vitro activity demonstrated that it is a promising therapy alternative for treating extensively drug-resistant P. aeruginosa in burn patients.

Evaluating the susceptibility to ceftazidime-avibactam in clinical isolates of Klebsiella pneumoniae and Pseudomonas aeruginosa recovered from an apex medical hospital in north India

Sat, 05 Apr 2025 10:04:24 +0430

Background and Objectives: We assessed the susceptibility of ceftazidime+avibactam (CZA/AVI) in Klebsiella pneumoniae and Pseudomonas aeruginosa isolated from intensive care units of our hospital.
Materials and Methods: Clinical samples from Jan 2022 to Dec 2023 at SKIMS Soura, were processed for the recovery of K. pneumoniae and P. aeruginosa. Susceptibility testing was done by disc diffusion (DD) method and minimum inhibitory concentration (MIC) for CZA/AVI and meropenem was assessed using E-test strips. Categorical agreement (CA), very major errors (VME), major errors (ME) and minor errors (mE) between DD and MIC were measured. Statistical analyses were performed using SPSS version 22.0.
Results: A total of 111 K. pneumoniae and 81 P. aeruginosa were part of the study. Of these, 56.8% K. pneumoniae and 45.7% P. aeruginosa isolates were susceptible to CZA/AVI. MIC of CZA/AVI for K. pneumoniae ranged from 0.125 to ≥ 256 μg/ml and for P. aeruginosa it ranged from 0.032 to 128 μg/ml. CA was 97.29% between DD and E-Test for CZA/AVI in K. pneumoniae isolates, with a ME of 2.70%. For P. aeruginosa CA between DD and E-Test for CZA/AVI was 98.76% with a VME of 1.23%. MIC values of meropenem were higher than CZA/AVI even in sensitive isolates.
Conclusion: CZA/AVI shows good in-vitro activity against clinical isolates of K. pneumoniae and P. aeruginosa and can be part of empirical therapy for treating infections caused by these bacteria.

The evaluation of antimicrobial resistance rates in infections caused by uropathogenic Escherichia coli strains collected from the south of Lebanon

Sajida Chreim, Seyed Masoud Hosseini, Abdallah Medlej, Mahdi Tarhini — Sat, 05 Apr 2025 10:04:55 +0430

Background and Objectives: Uropathogenic Escherichia coli (UPEC) is a leading cause of urinary tract infections, which are a significant public health concern worldwide. Antibiotic resistance among UPEC isolates is an increasing challenge, necessitating a better understanding of the resistance patterns and underlying genetic mechanisms. This study examined the prevalence of antibiotic resistance phenotypes and the detection of specific resistance genes among patients with UPEC infections in Sheikh Ragheb Harb University Hospital in south Lebanon.
Materials and Methods: Antimicrobial resistance phenotype of 104 urine samples was tested to determine the resistance percentages for various antibiotics including ampicillin, gentamicin, ciprofloxacin, tetracycline, bactrim, meropenem, and imipenem using disk diffusion test. Additionally, molecular analysis like polymerase chain reaction (PCR) was performed to detect the presence of bla_SHV, qnrA, tetA, dfrA1, aac3, bla_OXA and bla_IMP resistance genes.
Results: The antimicrobial resistance testing revealed the following resistance percentages for various antibiotics: ampicillin (100%), gentamicin (15.38%), ciprofloxacin (34.61%), tetracycline (48.07%), bactrim (17.3%), meropenem (0.96%) and imipenem (0.96%). The analysis of resistance genes showed the presence of bla_SHV (7.96%), qnrA (0.96%), tetA (20.19%), and dfrA1 (0.96%) genes, while the aac3, bla_OXA, and bla_IMP genes were not detected.
Conclusion: The high rates of antibiotic resistance observed, particularly to ampicillin and tetracycline, highlight the need for more judicious antibiotic use and the development of alternative treatment strategies to combat UPEC infections. These results can inform antimicrobial stewardship programs and guide the selection of appropriate empiric therapy for urinary tract infections.

Phenotypic and genotypic characterization of carbapenemase-producing Escherichia coli clinical isolates in Thi-Qar, Iraq

Moslim Mohsin Khalaf, Firas Srhan Abd Al-Mayahi — Sat, 05 Apr 2025 10:05:41 +0430

Background and Objectives: The emergence of carbapenem resistance in Escherichia coli (E. coli) poses an urgent threat. The study aims to assess carbapenem resistance and the presence of carbapenemase genes in E. coli clinical isolates from Thi-Qar Hospital, Iraq.
Materials and Methods: A total of 2203 specimens were collected from patients at two hospitals between January and October 2024. E. coli was identified via biochemical tests and confirmed with the Vitek2® system. Antibiotic sensitivity was evaluated using disc diffusion, and carbapenemase production was investigated through combined disc tests (CDT) and modified Hodge tests (MHT). PCR was used to detect carbapenemase genes.
Results: Out of 2203 specimens, 1212 (55.02%) exhibited bacterial growth, with E. coli accounting for 15.35% (186/1212) of isolates. Among these, 40 (21.51%) were resistant to at least one carbapenem. CDT identified 10, and MHT identified 1 as a carbapenemase producer. The most detected gene was bla_NDM (60.00%), followed by bla_OXA (40.00%) and bla_OXA-48 (15.00%). bla_OXA-51 and bla_VIM were found in 5.00% of isolates each. No bla_KPC, bla_NMC, bla_IMI, bla_GES, bla_SPM, bla_GIM, or bla_SIM was detected.
Conclusion: The high prevalence of carbapenem resistance and the corresponding encoding genes in E. coli in Thi-Qar province pose a concerning challenge for managing serious infections caused by this pathogen.

Design of ELISA-based diagnostic system for detection of enterohaemorrhagic Escherichia coli

Sat, 05 Apr 2025 10:06:44 +0430

Background and Objectives: Escherichia coli (E. coli) O157:H7 is an intestinal pathogen of humans and animals, which causes serious gastrointestinal, urinary tract infection and hemolytic uremic syndrome. Connecting to the host cell is important in pathogenesis. EspA, Intimin and Tir proteins (EIT) are the most important bacterial features in the process of binding. These antigens can be very useful in detecting these bacteria. The aim of this study was to produce recombinant EspA, Intimin and Tir proteins (rEIT) to detect pathogenic E. coli O157:H7 by means of ELISA method.
Materials and Methods: The eit recombinant gene was expressed using IPTG in E. coli BL21 (DE3) and evaluated by western blotting. The purified rEIT protein was injected to rabbits and mice subcutaneously. Purified antibody was evaluated using indirect, competitive and sandwich ELISA confirming the precise detection of E. coli O157: H7.
Results: Indirect, competitive and sandwich ELISA specifically detected E. coli O157:H7 and each methods had the ability to identify more than 10⁴, 10⁴, 10³ bacteria. The specificity of this method was evaluated by Entroheamoragic E. coli, enterotoxygenic E. coli, Klebsiella pneumoniae, Vibrio cholera and Acinetobacter.
Conclusion: These methods are the fastest, most accurate and cost effective methods for diagnosis of E. coli O157: H7, comparing to the conventional methods.

Molecular assessment of Coxiella burnetii in horses in Northwestern Iran

Sat, 05 Apr 2025 10:07:33 +0430

Background and Objectives: Q fever is a frequently occurring illness that is induced by the bacterium Coxiella burnetii (C. burnetii) that can infect humans and various animals. It targets the macrophage cells in the tissues, and circulating monocytes.
Materials and Methods: This study was conducted between 2022 and 2023 in the West Azerbaijan and Ardabil provinces of northwestern Iran to examine the presence infection of C. burnetii. Specimens were obtained by swabbing from 140 mares (70 from each province) and 20 stallions (10 from each province) which were apparently healthy, and their DNA was analyzed using quantitative PCR assay detecting the IS1111 element of the bacterium.
Results: The findings indicated that a mere 0.625% of the examined specimens tested positive for C. burnetii. Among the entire set of specimens, a single female horse from the region of Ardabil was found to be the carrier of the bacterium.
Conclusion: This suggested that even though horses may not display any clinical symptoms, they can still harbor C. burnetii and contribute to its transmission. Therefore, the potential contribution of horses to Q fever transmission should be considered.

Evaluation of the antagonistic effect of Pseudomonas aeruginosa toxins on azole antifungal resistance in Candida albicans species isolated from clinical samples in Iran

Sat, 05 Apr 2025 10:08:06 +0430

Background and Objectives: The azole antifungals are the most frequent class used to treat Candida infections. It is essential to elucidate the potential of natural compounds as an alternative in eliminating Candida albicans (C. albicans). Therefore, in the present study, the antagonistic effect of Pseudomonas aeruginosa toxins on azole antifungal resistance in C. albicans species was investigated.
Materials and Methods: In this study, 28 C. albicans species with azole antifungal resistance were obtained from patients at Shohadaye Tajrish Hospital. The effect of toxins, such as phenazine, pyocyanin, pyoverdine, and fluorescein, was examined on C. albicans species. The antifungal activity of these toxins against C. albicans spp. was determined using methods such as minimal inhibitory concentration (MIC₉₀), radial diffusion assay (RDA), and detection of reactive oxygen species (ROS).
Results: The prevalence of C. albicans strains in urinary catheters, surgical wounds, respiratory tracts, blood, and standard strains was 46.3%, 21.4%, 25%, 7.14%, and 3.57%, respectively. The MIC values were reported as 32 µg/ml for phenazine, and 128 µg/ml for pyoverdine, pyocyanin, and fluorescein. The results showed that phenazine exhibited higher inhibitory effects against C. albicans isolated from clinical samples compared to the other toxins. After exposure to phenazines (20 µg/ml), 65-70% of yeast cells of C. albicans spp. showed rhodamine 123 fluorescence, indicating high intracellular reactive oxygen species (ROS) production.
Conclusion: The antifungal effect of different toxins in C. albicans spp. may be due to ROS-mediated apoptotic death. The results suggest that phenazine has high potential in controlling C. albicans. This natural compounds are a potential alternative for eliminating this yeast.

Antifungal effect of soil Bacillus bacteria on pathogenic species of the fungal genera Aspergillus and Trichophyton

Sat, 05 Apr 2025 10:08:38 +0430

Background and Objectives: The increasing prevalence of fungal infections due to antifungal resistance underscores the need for novel treatment strategies. The present study aimed to investigate the inhibitory effects of soil-originated antagonistic bacteria against Aspergillus and Trichophyton species.
Materials and Methods: Fifty soil samples collected from Isfahan and Khuzestan provinces by using the Zig-Zag method were cultured on glucose-yeast extract (GY) agar around fungal colonies to isolate antagonistic bacteria. Antifungal activity was assessed by measuring clear zones around the colonies of A. niger, A. fumigatus, T. rubrum, and T. mentagrophytes by co-culture linear method. Potent antagonistic bacteria were identified by 16S rRNA sequencing, and evaluated for antifungal activity using disk diffusion assays compared with amphotericin B and ketoconazole.
Results: Among 50 samples, fifteen showed antifungal effects, yielding 55 bacterial strains. Four isolates with strong antifungal activity against all tested fungi were identified as Bacillus subtilis, B. licheniformis, B. axarquiensis, and Bacillus sp. These bacteria were distributed in distinct clusters phylogenitically and showed diverse antifungal activity.
Conclusion: The results suggest the potential of soil-derived Bacillus species as promising antifungal agents. Further studies are recommended to identify their inhibitory metabolites, their ability as biocontrol agents against soil habitated fungi and to explore their mechanism of action and spectrum of activity.

Impact of oleuropein on Candida albicans and Staphylococcus aureus adhesion and its mediated toxicity in Zebrafish (Danio rerio) embryos

Sat, 05 Apr 2025 10:09:09 +0430

Background and Objectives: The rising prevalence of antibiotic resistance and biofilm-associated infections poses significant challenges in clinical settings. This study investigates the antimicrobial and anti-adhesive properties of oleuropein, a compound derived from olive leaves, against Candida albicans and Staphylococcus aureus.
Materials and Methods: This study was conducted on Candida albicans (fluconazole-resistant/susceptible) and Staphylococcus aureus (methicillin-resistant/susceptible). The antifungal, antibacterial, anti-adhesion, and cell surface hydrophobicity (CSH) effects of oleuropein were evaluated. The impact of oleuropein on germ tube formation (GTF) in C. albicans was assessed. Finally, the toxicity of oleuropein was evaluated in zebrafish embryos.
Results: Oleuropein exhibited MIC values of 10 mg/ml for C. albicans and 5 mg/ml for S. aureus. It significantly (P< 0.05) reduced the adhesion of both microorganisms in a dose-dependent manner, with inhibition percentages of 78.43% and 75.91% for C. albicans and S. aureus, respectively. Additionally, oleuropein reduced the CSH of C. albicans, indicating its potential to interfere with adhesion mechanisms. In addition, oleuropein exhibited inhibition of GTF in C. albicans.
Conclusion: Oleuropein demonstrates significant antimicrobial and anti-adhesive properties against C. albicans and S. aureus, indicating its potential as a therapeutic agent for preventing biofilm-related infections. However, careful dosage management is crucial due to its observed toxicity at higher concentrations.

Onychomycosis among cancer patients undergoing chemotherapy in Tehran, Iran: a cross-sectional study

Sat, 05 Apr 2025 10:09:49 +0430

Background and Objectives: Due to the persistence of residual fungal elements, onychomycosis tends to have a high recurrence rate. It is essential to determine the etiology and frequency of onychomycosis across various factors. This study aimed to assess the prevalence of onychomycosis and identify its fungal agents in cancer patients undergoing chemotherapy.
Materials and Methods: This cross-sectional study was conducted on cancer patients attending the Oncology Clinic and Cancer Institute of Tehran University of Medical Sciences. Among the 165 patients meeting the inclusion criteria, 75 individuals with nail alterations were referred to a dermatologist. Each patient's information, including demographics, disease-related data, and details about nail involvement, was recorded. When onychomycosis was suspected, nail samples were collected from the deepest part and examined using a light microscope after clarifying with 15% potassium hydroxide (KOH) to detect fungal elements.
Results: The prevalence of onychomycosis was 37.6% (n=62). Among the 75 patients with nail alterations and suspected onychomycosis, 17.3% (n=13) tested negative for pathogenic agents. The most common pathogen was Candida albicans, present in 21% (13/62) of patients with positive onychomycosis. The prevailing nail alteration was onycholysis, affecting 45.3% (34/75) of patients.
Conclusion: Onychomycosis exhibits associations with variables such as gender, age, cancer and chemotherapy.

Investigating the ability of Saccharomyces cerevisiae and Lactobacillus plantarum on the reduction of aflatoxin B1, ochratoxin A, and zearalenone in dough and toast Bread

Alireza Haji Amiri, Leila Nateghi, Nazanin Zand — Sat, 05 Apr 2025 10:10:20 +0430

Background and Objectives: Wheat and its derived products are high-risk commodities for aflatoxin contamination. The objective of this study was to investigate the effect of using Saccharomyces cerevisiae, Lactobacillus plantarum, and the dough fermentation and baking periods on reducing aflatoxin B₁ (AFB₁), ochratoxin A (OTA), and zearalenone (ZEA) toxins.
Materials and Methods: Toast bread flour contaminated with AFB₁, OTA and ZEA (10,10 and 400 ng/g) were separately treated with S. cerevisiae and L. plantarum (at a concentration of 10⁸ CFU/g). The reduction of mycotoxins was examined immediately after dough preparation, at the end of fermentation, and after
baking.
Results: The type of microorganism, fermentation and baking significantly affected the reduction of mycotoxins (AFB₁, OTA, and ZEA). After baking, neither AFB₁ nor OTA were detected in any of the toast bread samples, with a 100% reduction observed in all treatments. In contrast, the percentage reduction of ZEA after baking compared with immediately after dough preparation ranged from 98.90% to 100%, and the percentage reduction of ZEA at the end of fermentation compared with immediately after dough preparation ranged from 97.80% to 99.57%.
Conclusion: The findings of this study suggest that L. plantarum and S. cerevisiae can be used as additives or processing agents to decrease mycotoxins in fermented wheat foods.

Antifungal activity of polyphenolic compounds against fluconazole-susceptible and -resistant Candida species

Sat, 05 Apr 2025 10:10:53 +0430

Background and Objectives: The rapid emergence of resistant fungi is occurring worldwide, and this crisis has been attributed to the lack of new antifungal drug development. This issue emphasizes the need for innovation in finding novel antifungals. There is an increasing interest in using the natural products of plants with high biological activity as alternatives to synthetic drugs. This study aimed to evaluate the possible applicability of polyphenols as alternative antifungal drugs to treat resistant Candida infections.
Materials and Methods: A panel of fluconazole-resistant (n=14) and fluconazole-susceptible (n=26) clinical Candida isolates was obtained from the reference culture collection. The determination of the minimum inhibitory concentrations (MICs) of fluconazole, tannic acid, rosmarinic acid, gallic acid, chlorogenic acid, caffeic, ferulic, and p-coumaric was carried out following the Clinical and Laboratory Standards Institute (CLSI) guidelines.
Results: The MIC values of 40 Candida species isolates ranged from 0.25 to >64 µg/mL for polyphenolic compounds. The highest inhibitory effect against Candida species was observed with tannic acid, followed by fluconazole. Non-albicans Candida groups were more sensitive to tannic acid compared to C. albicans isolates. Significant differences were observed in the MICs of fluconazole and tannic acid against non-albicans Candida isolates.
Conclusion: The increasing antifungal resistance highlights the importance of evaluating new drugs that are more robust against resistance. This study suggests that tannic acid could be considered a novel antifungal agent for managing fungal infections, including multidrug-resistant non-albicans Candida infections.