Iranian Journal of Microbiology最新文献

Background and objectives: The consumption of contaminated poultry meat is considered as a significant route of campylobacteriosis transmission. Lactic acid is a disinfectant agent with bactericidal effects on Campylobacter spp. The purpose of this study was to assess the low concentrations of lactic acid effect and different temperatures on the transcriptomic responses of Campylobacter jejuni (C. jejuni) adhesion and virulence-associated genes including peb4, ciaB, cdtA, cdtB, and cdtC.

Materials and methods: The samples were incubated at 10°C and 22°C for 48 h upon exposure to 30% and 60% lactic acid. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of lactic acid was also determined. Then, gene expression was assessed using real-time polymerase chain reaction (RT-PCR).

Results: Lactic acid had lower MIC and MBC levels at lower temperature. The utilization of both levels of lactic acid significantly reduced the expression of peb4, ciaB, cdtB, and cdtC genes over 48 h of incubation at 22°C. However, no significant difference was found in the expression of the cdtA gene between 10 and 22°C at 30% lactic acid.

Conclusion: These results highlight the potential of low-concentration lactic acid in the downregulation of adhesion and virulence-associated genes as well as reduction of C. jejuni pathogenicity.

Background and objectives: Fungal burn wound infections (FBWIs) are one of the most disastrous complications in burn patients. The present study investigated the incidence and the species distribution of fungal agents isolated from burn lesions and reviewed the feautures, underlying conditions, and outcomes of patients.

Materials and methods: The wounds were swabbed and cultured on Sabouraud Dextrose Agar with chloramphenicol medium. Fungal identification was performed using internal transcribed spacer (ITS) and beta-tubulin sequencing.

Results: A total of 380 swab specimens were obtained. Of these, 101 patients (26.75 %) were positive in culture. Among the 101 positive cases, most isolates were from males (n= 68, 67.33%) and most of them were over 30 years old. Flame (n=38, 37.63%) was the predominant cause of burns, and previous history of ICU admission (n=35, 34.66%), presence of central venous catheter (n=25, 24.75%), and diabetes mellitus (n=17, 16.83%) were the main underlying conditions. Candida parapsilosis complex (n=36, 35.64%), and Pichia kudriavzevii (C. krusei) (n=8, 7.92%) represent the most commonly isolated species Also, 2 out of 101 patients (2%) died.

Conclusion: In the present study, non-albicans Candida species were much higher frequent than C. albicans with most cases associated with Candida parapsilosis complex.

Background and objectives: Cervical cancer global burden is highly skewed towards poor countries primarily due to lack of awareness, poor screening, and low uptake of prophylactic vaccines. The purpose of our study is to educate and raise awareness among young girls and women about the importance of cervical screening and HPV vaccination.

Materials and methods: The present study, conducted from January 2023 to December 2023, focused on students, teachers, housewives, and healthcare professionals in the Jammu region to assess their awareness of cervical cancer and the HPV vaccine. HPV DNA testing was carried out using the Truenat Real-Time PCR method at Swastik Diagnostic Laboratory, Jammu.

Results: Knowledge of cervical cancer, awareness of the HPV virus, and the vaccination status of women were assessed in survey. In the HPV screening test, out of 2,400 women, 106 tested positive for HPV. Among these 106 women, 19% had a high viral load (Ct < 20), 11% had a low viral load (25 ≤ Ct < 30), indicating a low relative concentration of HPV viruses, 40% had a medium viral load (20 ≤ Ct < 25), and 30% had very low viral loads (Ct ≥ 30).

Conclusion: These findings highlight the importance of routine cervical screenings, such as Pap smears and HPV tests, for the early detection of cervical cancer. There is an urgent need to implement cervical cancer screening and vaccination programs in the Jammu region.

Background and objectives: The ocular surface is perpetually exposed to the external environment, rendering it susceptible to microbial contamination. The ocular surface microbiota consists of non-pathogenic microorganisms that inhabit the conjunctiva and cornea. This study's objective was to extensively review the prevalence of bacterial and fungal organisms in the conjunctiva of healthy and diseased cats. (Herpes- and Calici-infected groups).

Materials and methods: The current study was performed on 240 cats that had visited veterinary health centers (Tehran, Iran) for examination. Sterile swabs from each cat's eyes were investigated for microbiological assessment. After sample collection, viral pathogens (Herpes and Calici viruses) were isolated and identified using the PCR method. The ages of the investigated group were 3.76, 3.93, and 4.15 months.

Results: The highest frequency of bacteria in the normal, Herpes-infected/Calici-infected, and Herpes/Calici-infected groups were associated with Staphylococcus intermedius and Streptococcus agalactiae, Staphylococcus epidermidis, and Staphylococcus intermedius, respectively. In addition, it was found that the high prevalence of fungal microorganisms in the isolated samples was related to yeasts, Aspergillus (Aspergillus fumigatus, Aspergillus niger), and Penicillium species.

Conclusion: Bacterial prevalence was significantly higher in all groups than the prevalence of fungi in the eyes of cats. The statistical comparison between the study groups regarding microbial and fungal frequency showed that significant differences were found between them, such that the frequency was higher in all disease groups, against the control group. In addition, a significant relation was observed between the Herpes-infected and Calici-infected groups regarding microbial and fungal prevalence.

Background and objectives: Today, medicinal plants and their derivatives are considered to reduce the prevalence of antibiotic resistance. The aim of this study was to investigate the effect of Mentha longifolia essential oil on oqxA efflux pump gene expression and biofilm formation in ciprofloxacin-resistant Klebsiella pneumoniae strains.

Materials and methods: A total of 50 clinical strains of K. pneumoniae resistant to ciprofloxacin were studied. The minimum inhibitory concentration (MIC) of M. longifolia essential oil and its synergistic effect with ciprofloxacin were determined using the microbroth dilution method and the fractional inhibitory concentration (FIC) method. Minimum biofilm inhibition concentration (MBIC) of M. longifolia essential oil was detected. The effect of essential oils on the expression level of the oqxA gene was detected by Real-time PCR.

Results: M. longifolia essential oil showed inhibitory activity against ciprofloxacin-resistant strains of K. pneumoniae. When M. longifolia essential oil was combined with ciprofloxacin, the MIC was reduced 2-4 times. In 28% of the strains, M. longifolia with ciprofloxacin showed a synergistic effect. M. longifolia essential oil reduces the strength of biofilm formation and alters the biofilm phenotype. A significant decrease in oqxA gene expression was observed in all isolates after treatment with M. longifolia essential oil.

Conclusion: Based on the results of this study, it was observed that supplementing M. longifolia essential oil can help reduce ciprofloxacin resistance and inhibit biofilm formation in fluoroquinolone-resistant K. pneumoniae strains.

Background and objectives: This study evaluated the efficacy of the TrueLab™ Real Time mini-PCR system in providing rapid and accurate diagnostic results for tuberculosis (TB) detection in India. The goal is to improve case detection and accelerate treatment in settings with limited resources.

Materials and methods: This prospective study was conducted by the Department of Microbiology on 120 patients, age ranging from >=15 years with at least two clinical symptoms of pulmonary TB. Molbio and Universal Cartridge Based Sample Prep were the 2 methods used for processing sputum samples. The diagnosis was based on the MTB Real Time PCR test, which has a detection limit of 100 CFU/mL. Patients under 15 years, samples lacking clinical background, saliva specimens or extra-pulmonary TB cases were excluded from the study.

Results: A total of 44.17% samples were positive for TB with maximum positivity in the age group 31-45 years. Positivity rate was found to be higher in females. In 4.17% of cases there was rifampicin resistance, which was significantly high in previously treated cases. Comparison of Truenat with Ziehl-Neelsen and fluorescent method revealed that it was more sensitive and less time consuming.

Conclusion: Truenat MTB/RIF is a sensitive detection system for TB with rapid results, which serves as an important tool in the early management of tuberculosis patients and drug-resistant-TB cases.

Background and objectives: SARS-CoV-2 is a newly discovered viral infection. It's still unclear how antibodies react in infected individuals, and there is not enough evidence to support the clinical use of antibody examination. This study evaluates the diagnostic value of serologic tests for diagnosing COVID-19.

Materials and methods: 32 patients for whom serologic testing was performed within 7 to 21 days from symptom onset and whether they were diagnosed with COVID-19 by both PCR and lung HRCT as gold standard tests at the same time, were included in the study.

Results: Serologic tests (IgM / IgG) compared to PCR and lung HRCT scan to diagnose COVID-19, were 89.3% specific and 59.6% sensitive. Positive predictive value (PPV) was 95% and negative predictive value (NPV) was 37%. The diagnostic accuracy index of the serologic test was 0.745 (CI 0.651-0.838) (p-value <0.001).

Conclusion: Serologic testing can be a complementary alternative for SARA-CoV-2 nucleic acid RT-PCR, although it cannot replace it completely. IgG/IgM combo test kits and RT-PCR together can give more insight into the diagnosis of SARS-CoV-2.

Background and objectives: This study aimed to evaluate the frequency of multidrug-resistant (MDR) bacteria in biliary samples, MDR-bacteria risk factors, and the relationship between MDR-bacteria positivity and some clinical outcomes.

Materials and methods: The study was conducted between May 2018 and May 2023, including patients over the age of 18 who had positive culture results in biliary samples. The frequency of MDR-bacteria in biliary samples was evaluated. Risk factors for MDR bacteria were assessed using univariate and multivariate analyses. MDR and non-MDR groups were compared inappropriate empirical antibiotic treatment, total antibiotic treatment duration, length of stay, and in-hospital mortality.

Results: 342 microorganisms were isolated from 202 patients. Escherichia coli was the most commonly (37.2%) isolated Gram-negative microorganism, and Enterococcus spp. was the most commonly (70.2%) isolated Gram-positive microorganism. The incidence of MDR microorganisms was 42.3%. Gastrointestinal malignancy (OR: 1.96; 95% CI, 1.03-3.71) and previous antibiotic use (OR: 2.26; 95% CI, 1.09-4.68) were independent risk factors for MDR-bacteria. In the MDR group, inappropriate empirical antibiotic treatment (56.6% vs. 41%, p = 0.091), total antibiotic treatment duration (13 vs. 8 days, p = 0.054), length of stay (24 vs. 15 days, p = 0.001), and in-hospital mortality (27.3% vs. 22.3%, p = 0.416) were higher compared to the non-MDR group.

Conclusion: MDR-bacteria positivity is associated with inappropriate antibiotic treatment, prolonged hospitalization, and increased mortality. Screening, antibiotic prophylaxis, and empirical treatment approaches should be carefully performed in patients with malignancy and recent antibiotic use, which are significant risk factors for MDR-bacteria.

Background and objectives: The most common cause of healthcare-associated diarrhea is Clostridium difficile infection (CDI), which causes severe and recurring symptoms. The increase of antibiotic-resistant C. difficile requires alternate treatments. Postbiotics, metabolites produced by probiotics, fight CDI owing to their antibacterial capabilities. This study aims to evaluate the antibacterial, antibiofilm, and anti-toxigenic potential of postbiotics in combating CDI.

Materials and methods: GC-MS evaluated postbiotics from Bifidobacterium bifidum and Lactobacillus plantarum. Disk diffusion and broth microdilution determined C. difficile antibacterial inhibition zones and MICs. Microtiter plates assessed antibiofilm activity. MTT assay evaluated postbiotics anti-viability on HEK293. ELISA testing postbiotic detoxification of toxins A and B. Postbiotics were examined for tcdA and tcdB genes expression using real-time PCR.

Results: The most identified B. bifidum and L. plantarum postbiotic compounds were glycolic acid (7.2%) and butyric acid (13.57%). B. bifidum and L. plantarum displayed 13 and 10 mm inhibition zones and 2.5 and 5 mg/ml MICs against C. difficile. B. bifidum reduced biofilm at 1.25 mg/ml by 49% and L. plantarum by 31%. MTT assay showed both postbiotics had little influence on cell viability, which was over 80%. The detoxification power of postbiotics revealed that B. bifidum decreased toxin A and B production more effectively than L. plantarum, and also their related tcdA and tcdB genes expression reduction were statistically significant (p < 0.05).

Conclusion: Postbiotics' ability to inhibit bacterial growth, biofilm disruption, and toxin reduction makes them a promising adjunctive for CDI treatment and a good solution to pathogens' antibiotic resistance.

Background and objectives: Rifampicin (RIF) and isoniazid (INH), two most potent antibiotics, are prescribed to cure tuberculosis. Mycobacterium tuberculosis, the causative agent of multidrug-resistant tuberculosis (MDR-TB), is resistant to these first-line drugs. Here, two molecular techniques were demonstrated such as PCR sequencing-based and GeneXpert assay for rapidly identifying MDR-TB.

Materials and methods: Pulmonary samples (sputum) were collected from 55 MDR-TB suspected patients from the National Tuberculosis Reference Laboratory (NTRL), Dhaka where the research work was partially accomplished and continued in the department of Microbiology, University of Dhaka, Bangladesh. We strived for sequencing technique as well as GeneXpert assay to identify mutations in rpoB and katG genes in MTB strains and sputum directly. Culture-based drug susceptibility testing (DST) was performed to measure the efficacy of the molecular methods employed.

Results: When analyzed, rpoB gene mutations at codons 531 (54.54%), 526 (14.54%), and 516 (10.91%) were found by sequencing in 80% of the samples. Nucleotide substitution at katG315 (AGC→ACC) was spotted in 16 (76.19%) out of 21 samples. When comparing the sequencing results with DST, sensitivity and specificity were investigated to determine drug-resistance (rifampicin-resistance were 98 and 100% whereas isoniazid-resistance were 94 and 100% respectively). Additionally, as a point of comparison with DST, only 85.45% of RIF mono-resistant TB cases were accurately evaluated by the GeneXpert assay.

Conclusion: This research supports the adoption of PCR sequencing approach as an efficient tool in detecting MDR-TB, counting the higher sensitivity and specificity as well as the short period to produce the results.