Iranian Journal of Microbiology最新文献

Background and objectives: Rumen microbiologists are looking for new probiotics to improve the digestibility of livestock diets. This study intended to screen and evaluate the ruminal cellulolytic bacteria (CBs) and their potential application as probiotics.

Materials and methods: Microbial culture and molecular techniques performed to isolate CBs from the rumen of camels, deer and rams. Their antibacterial and antibiogram tests were done using disc diffusion method. Their potential to degrade cellulose, starch, tannin and protein were investigated using clear zone halo, and spectrophotometric techniques. Bilious, saline, and acidic broth media were used to study the resistance of isolates in intestinal conditions.

Results: The phylogenetic analysis revealed that the strains belonged to Firmicutes and Proteobacteria phyla, Citrobacter murliniae, Ornithinibacillus bavariensis, C. braakii, and Bacillus subtilis. The highest cellulase (CAS) activity was recorded by C. murliniae Dez wildlife13A (2.98 UmL^-1), whereas C. braakii Loot desert 111A (1.14 Uml^-1) was produced the lowest enzyme. The isolates were highly resistant to synthetic conditions of intestine (pH 2.5-3.5, bile 0.3-2%), as well as tolerated higher concentrations of NaCl (up to 10%). They effectively inhibited standard pathogen strains, and showed sensitivity to the used antibiotics.

Conclusion: This study reports the cellulolytic O. bavariensis Tabbas desert 32A for the first time from the rumen, which will have potential biotechnological applications.

Background and objectives: Although several studies have been achieved on the frequency of the HPV types among women with cervical cancer in Iran, HPV-positive samples were in some cases directed to specific-primer genotyping of HPV 16 and 18. Therefore, the other HPV types are underestimated. Several studies have also reported a greater prevalence of HPV 16 in cervical cancer in Iran than in the world. To clarify these subjects, the distribution of HPV types in women referred for colposcopy in Tehran was investigated.

Materials and methods: In this cross-sectional study, a total of 148 cervical samples from women with normal, atypical squamous cells of undetermined significance, cervical intraepithelial neoplasia I-III, and invasive cervical cancer histopathology were included. HPV was detected by PCR assay and all HPV-positive specimens were subjected to direct nucleotide sequencing.

Results: Our results demonstrated that the total prevalence of HPV was 92.5%. The five most common HPV types were HPV 16 (49.3%), 18 (14.8%), 6 (7.4%), 31 (4.1%), and 11 (2.7%). About the histopathological stage, HPV 16 and 18 were dominant in all studied groups. In cervical cancer, HPV 16 and 18 were detected in 60% and 20% of cases, respectively.

Conclusion: HPV 16 and 18 were the most common in cervical cancer in Iran.

Background and objectives: Lipoarabinomannan is one of the components of the significant structural cell surfaces of mycobacteria and serves as an immunostimulatory factor. TNF-α and IL-12 are two examples of the anti-bacterial inflammatory cytokines that are activated and induced during infection.

Materials and methods: In this study, mannan was extracted and processed, and then Bulb/c female mice were used in three groups, one group was given BCG vaccine, the other group was given BCG vaccine with mannan adjuvant, and a non-injected group was used as a control group. Inflammatory factors interleukin-12, TNF-α, IgG and IgM were measured in mouse serum.

Results: The levels of the inflammatory factors interleukin-12 and TNF-α in the serum isolated from mice receiving the BCG vaccine with mannan adjuvant showed a significant difference compared to the group that received only the BCG vaccine and the control group [IL-12] and , with P≤0.05.The examination of the level of IgG immune factors in these three groups revealed a significant difference. The group that received the BCG vaccine with mannan adjuvant showed a marked contrast compared to the group that received only the BCG vaccine and the control group, with P≤0.05. The level of IgM was higher in the group that received the BCG vaccine alone compared to the adjuvant vaccine group and the control group, with P≤0.05.

Conclusion: Our results indicated that mice receiving the BCG vaccine with mannan adjuvant had significantly higher serum levels of IL-12, TNF-α, and IgG than the group receiving BCG alone.

Background and objectives: To explore the prevalence and characteristics of secondary bacterial infections among patients suffering from mucormycosis following COVID-19 infection.

Materials and methods: We conducted a cross-sectional, retrospective analysis from March 2020 to April 2022 at Imam Khomeini Hospital Complex in Tehran. The study included patients with histopathologically confirmed mucormycosis and documented secondary bacterial infections. We extracted and analyzed data from hospital records using SPSS software, version 26.

Results: The study comprised 27 patients, with a predominance of females (70.4%) and an average age of 56 years. The majority of these patients (63%) had pre-existing diabetes mellitus. The severity of their COVID-19 infections varied. Treatment regimens included immunosuppressive drugs and antibiotics. Rhinocerebral mucormycosis was the most common form observed. The predominant secondary infections involved the urinary tract, respiratory system, bloodstream (bacteremia), and soft tissues, with resistant strains of Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae being the most frequently identified microorganisms. Notably, cases of bacteremia and pneumonia exhibited a higher mortality rate. Ultimately, 55.6% of patients were discharged, while 44.4% succumbed to their infections.

Conclusion: Patients recovering from COVID-19 with mucormycosis are significantly susceptible to secondary bacterial infections, particularly those with diabetes mellitus or those undergoing immunosuppressive therapy. Such infections compound the morbidity and mortality risks in this vulnerable patient cohort.

Background and objectives: Pseudomonas aeruginosa, drug-resistant, causes health infections. Resistance to the preferred therapy meropenem is a serious threat. This study aimed to analyze changes in meropenem minimum inhibitory concentration (MIC), changes in ampC, mexA, and oprD gene expression, and the correlation between MIC and ampC, mexA, and oprD gene expression after meropenem exposure.

Materials and methods: Ten isolates of P. aeruginosa from the Clinical Microbiology Department, Faculty of Medicine, Universitas Indonesia were used. After the bacteria were shown to be sensitive to meropenem phenotypically, intrinsic resistance genes were detected using PCR. After meropenem exposure on Days 5 and 12, sensitivity testing was carried out with the concentration gradient method and RNA was detected using real-time RT-PCR.

Results: All P. aeruginosa isolates that were phenotypically sensitive to meropenem had the ampC, mexA, and oprD genes. An increase in MIC, an increase in ampC and mexA gene expression, and a decrease in oprD gene expression were observed after meropenem exposure. There was a very strong and significant correlation (p ≤ 0.05) between MIC and oprD gene expression after Day 12 of meropenem exposure.

Conclusion: Although there were no significant differences in MIC and ampC, mexA, and oprD gene expression between Day 5 and Day 12, there was a very strong and significant correlation between MIC and oprD gene expression on Day 12 (p ≤ 0.05). This indicates that decreasing oprD gene expression has the potential to increase meropenem resistance in Pseudomonas aeruginosa.

Background and objectives: TB infection is one of the most challengeable epidemiological issues. Complex interactions between microbiota and TB infection have been demonstrated. Alteration in microbial population during TB infection may act as a useful biomarker. The present study examined the microbiota patterns of blood and sputum samples collected from Afghan immigrants and Iranian patients with active TB.

Materials and methods: Sixty active pulmonary TB patients were enrolled in the study. Blood and sputum samples were collected. To detect phylum bacterial composition in the blood and sputum samples, bacterial 16S rRNA quantification by Real-Time qPCR was performed.

Results: A significant decrease in Bacteroidetes in Iranian sputum and blood samples of Afghan immigrants and Iranian TB active subjects were seen. While, sputum samples of Afghan immigrants showed no significant differences in Bacteroidetes abundance among TB active and control. Firmicutes were also presented no significant difference between sputum samples of the two races. Actinobacteria showed a significant increase in Iranian and Afghan sputum samples while this phylum showed no significant abundance in Iranian and Afghan TB positive blood samples. Proteobacteria also showed an increase in sputum and blood samples of the two races.

Conclusion: An imbalance in Bacteroidetes and Firmicutes abundance may cause an alteration in the microbiota composition, resulting in dysregulated immune responses and resulting in the augmentation of opportunistic pathogens during TB infection, notably Proteobacteria and Actinobacteria. Evaluation of human microbiota under different conditions of TB infection can be critical to a deeper understanding of the disease control.