Iranian Journal of Microbiology最新文献

Background and objectives: Acinetobacter baumannii (A. baumannii) is an opportunistic bacterial pathogen principally related with hospital-acquired infections. This study aimed to isolate and identify A. baumannii strains, investigate their resistance to various antibiotics, and characterize A. baumannii at the molecular level.

Materials and methods: A total of 100 samples were obtained from various hospital departments, including the intensive care unit (ICU), emergency room, kidney dialysis and surgery units. The incidence of drug resistance was studied using the Vitek 2 Compact system and further using molecular techniques such as polymerase chain reaction to analyze the genes responsible for resistance.

Results: The study exhibited a high prevalence of multidrug-resistant (MDR) A. baumannii isolates, especially in ICU patients. The males were the predominant group, accounting for 60% whereas females were 40%. The most frequent samples were from urine (43%) and skin (24%). Majority of samples were from the ICU (42%) and emergency departments (20%). The tested isolates exhibited the highest resistance (66%) to oxacillin, whereas the maximum sensitivity (52%) was recorded for Erythromycin. Molecular analysis revealed the occurrence of resistance genes bla _OXA-23, bla _OXA-24 , bla _OXA-51, and bla _OXA-58, which contribute to carbapenem resistance.

Conclusion: The findings emphasize that A. baumannii remains a formidable nosocomial pathogen, and there is pressing requirement for enhanced infection control procedures and antibiotic stewardship. Through improved molecular observation, judicious use of antibiotics and improved infection control practices, healthcare providers can alleviate the impact of MDR A. baumannii infections and improve the prognosis for affected patients in Jordan and beyond.

Background and objectives: The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants has presented a challenging issue for global health in the 21^st century. Frequent mutations in viral genomes have diminished the effectiveness of current vaccines against new variants. Messenger RNA (mRNA) vaccine is a promising platform for eliciting a robust T cell immune response.

Materials and methods: We evaluated the uptake of mRNA-LNPs into human monocyte-derived dendritic cells by measuring the intensity of enhanced eGFP expression in the transfected cells. Next, we assessed the effect of mRNA-LNPs on immune response induction in mice following a prime-boost immunization strategy, along with analyzing cytokine release. The safety of the vaccine candidate was examined through pyrogenicity and toxicity assays.

Results: Upon intramuscular injection of mice, potent antibodies specific to viral S protein, robust Th1-biased cell-mediated immunity, and enhanced IFN-γ expression were induced. These observations indicate that mRNA-LNP was taken up and that it migrated to the lymph nodes. Furthermore, the vaccine candidate did not cause inflammation or local reactions after injection, as confirmed by biochemical, hematological, and histopathological examinations.

Conclusion: Because of its ability to target immune cells, the mRNA vaccine candidate can potentially improve immune responses against circulating or emerging variants.

Background and objectives: Brucellosis, a contagious infection caused by Brucella spp, remains the most widely reported bacterial zoonosis globally. Since the clinical manifestations are often non-specific, reliable laboratory confirmation, in accordance with World Health Organization recommendations, is essential. This study reports human brucellosis cases between 2017 and 2025 based on serological confirmation; it also discusses approaches to improve diagnostic accuracy for better surveillance, timely treatment, and support public health strategies.

Materials and methods: A total of 95 serum samples were obtained from patients presenting with clinical manifestations suggestive of brucellosis. Initial screening was performed using the Rose Bengal test, and positive or equivocal samples were further analyzed by Enzyme-Linked Immunosorbent Assay to detect both IgG and IgM antibodies for serological confirmation.

Results: Among the 95 patients investigated, the Rose Bengal test yielded positive results in 69.5% of cases. Serological confirmation by ELISA demonstrated IgM seropositivity in 57.9% of patients and IgG seropositivity in 55.8%. The diagnostic performance of ELISA showed a sensitivity of 83.3% for IgM detection and 80.3% for IgG detection. Regarding patient demographics, the mean age was 37.9 ± 16.4 years, with a slight male predominance (54.7%).

Conclusion: The study reveals a considerable proportion of brucellosis-positive cases, confirming the value of serological testing in endemic regions such as Morocco. Nonetheless, serology should be complemented with advanced diagnostic methods, including PCR to improve both the accuracy and timeliness of diagnosis. These findings support the adoption of integrated diagnostic approaches and the reinforcement of laboratory capacity in high-risk areas.

Background and objectives: Neonatal septicemia is a significant cause of morbidity and mortality in neonatal intensive care units (NICUs). Understanding the patterns of antibiotic resistance and pathogen prevalence is crucial for effective treatment.

Materials and methods: This cross-sectional study was conducted from 2016 to 2022 in the NICU of Vali-Asr Hospital in Tehran. All neonates diagnosed with septicemia were included. Data were collected using the hospital's registry system.

Results: A total of 477 infants were hospitalized with sepsis, with 71.7% classified as early-onset sepsis (EOS) and 28.3% as late-onset sepsis (LOS). The most common pathogens were coagulase-negative Staphylococcus (22.1%), Klebsiella pneumoniae (14.9%), and Staphylococcus epidermidis (14.3%). The highest antibiotic resistance was observed for erythromycin (89.8%), clindamycin (80.6%), gentamicin (66.1%), and ciprofloxacin (63.5%), while vancomycin showed the lowest resistance (11.2%). Significant associations were found between antibiotic resistance with low birth weight and chest tube intervention. Trends in antibiotic resistance varied over the study period, with a notable decrease in resistance in 2021.

Conclusion: The study highlights the high prevalence of antibiotic resistance in neonatal sepsis, emphasizing the need for continuous monitoring and tailored antibiotic stewardship programs. The findings underscore the importance of individualized treatment approaches to improve outcomes for neonates with sepsis.

Background and objectives: Bacterial polysaccharides have diverse applications, including antimicrobial compounds, bio-preservatives, prebiotics, and wound-healing hydrogels. Weissella confusa is notable for its high polysaccharide yield among lactic acid bacteria.

Materials and methods: The bacteria were identified via 16s rRNA and exopolysaccharide (EPS) production was performed in a 10% skim milk and 10% sucrose medium. FT-IR, SEM, and HPTLC analyzed functional groups, spatial structure, and EPS units. Moreover, MTT assay, DPPH, and Kirby-Bayer disk method assessed cell proliferation, antioxidant activity, and antimicrobial effects of EPS. Additionally, Prebiotic potential and growth kinetics of exopolysaccharide were examined using the Thitiratsakul method. Furthermore, EPS effects on MMP and TIMP gene expression in fibroblast cells were evaluated.

Results: The purified polysaccharide from W. confusa B4-2 (Accession: KY290603), with a yield of 53 g/L, consists of glucose, fructose, and diglucuronic acid. This non-toxic polysaccharide (99-100% cell survival) exhibits 75% free radical scavenging activity along with significant antimicrobial effects against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. It also shows a high prebiotic score (0.912), accelerating wound healing in fibroblast cells while reducing collagen-degrading gene expression, particularly matrix metalloproteinases (MMPs). Notably, exopolysaccharides downregulated MMP1, MMP2, MMP3, and MMP9 gene expression levels by approximately 1.3, 1.2, 1.5, and 1.16 times, respectively.

Conclusion: These features highlight the commercial significance of W. confusa in the food, pharmaceutical, and health industries, surpassing lactobacilli with lower production yields.

Background and objectives: Subunit vaccines have the privilege of utilizing immunogenic parts of the variable viruses. The current preventive vaccines against Hepatitis A are based on live-attenuated virus or wild-type growth in cell culture, which is a time-consuming and costly procedure. Thus, the investigation of immunogenic Hepatitis A Virus (HAV) regions seems to be a rational priority. We aimed to evaluate a novel chimeric protein composed of truncated HAV-VP1 and Hepatitis B surface antigen (HBsAg) as a bivalent vaccine candidate in BALB/c mice.

Materials and methods: The HAV-VP1 (amino acids 99 to 259) and HBsAg fusion protein were applied as a bivalent vaccine in combination with adjuvants. The purified protein was administered through different regimens via subcutaneous injection. Two weeks following the final immunization, serum samples were gathered to assess the humoral responses. Moreover, splenocytes were investigated and assessed for IL-5 and IFN-γ secretion.

Results: The immunized mice with recombinant truncated HAV-VP1-AAY-HBsAg showed a significant immune response, especially in combination with the M720 adjuvant. Humoral immune response results indicated Th1 switching by IgG2a and IgG2b dominancy. Moreover, IFN-γ secretion reached the highest rate in the truncated HAV-VP1-AAY-HBsAg+M720 recipients (p<0.0001).

Conclusion: The HAV-VP1-AAY-HBsAg protein subunit vaccine could help the immune system fight HAV and HBV by stimulating both the humoral and cellular immune systems. The formula proposed in this study has the potential to produce an endemic vaccine based on the circulating HAV viruses in Iran.

Background and objectives: Yeasts play a dual role in dairy processing, serving as beneficial fermentative agents that enhance product quality through flavor, texture, and probiotic properties, while also posing spoilage risks if uncontrolled. This study aimed to characterize yeast isolates from industrial and traditional dairy products in Isfahan using PCR-sequencing and phylogenetic analysis.

Materials and methods: A total of 155 dairy samples (fresh/stored, traditional/industrial) were collected. Yeasts were cultured and identified via PCR amplification and sequencing of the ITS1-5.8S rDNA-ITS2 region.

Results: Analysis of ITS sequence data identified 28 yeast strains representing eleven species across seven genera, including Saccharomyces cerevisiae (n=8) Kluyveromyces marxianus (n=6), Pichia kudriavzevii (n=4), Candida orthopsilosis (n=2), Pichia membranifaciens (n=2), Pichia cactophila (n=1), Pichia fermentans (n=1), Galactomyces candidum (n=1), Torulaspora delbrueckii (n=1), Debaryomyces hansenii (n=1), and Kluyveromyces lactis (n=1). Phylogenetic analysis grouped isolates into two clusters. Industrial cheese and both industrial/traditional yogurts showed the highest yeast diversity and counts. Notably, C. orthopsilosis was found only in industrial milk and cheese, suggesting potential processing-related contamination.

Conclusion: This study highlights the diversity of yeast microbiota in dairy products and underscores the efficacy of ITS sequencing for accurate yeast identification in the dairy industry, aiding quality control and spoilage prevention.

Background and objectives: The aim of this study was to identify the incidence of nosocomial fungal infections in pediatric patients and evaluate the etiological agents, risk factors, and sites of infections.

Materials and methods: Clinical samples were cultured to assess fungal colonization. When fungal nosocomial infections were suspected according to the European Organization for Research and Treatment of Cancer criteria, clinical samples were evaluated using direct microscopic, culture, and molecular methods. Susceptibility patterns of the isolates were evaluated according to the Clinical and Laboratory Standard Institute.

Results: From the 1450 patients, 190 cases (5.5%) were evaluated for nosocomial fungal infections. Candida colonization was observed in 35 (18.4%) patients. The rate of nosocomial fungal infections in pediatrics was 2.69% (12 cases with proven and 27 cases with probable infections, 39/1450). Bloodstream and lungs were the frequent infected sites of patients' body. Aspergillus species (Aspergillus flavus and Aspergillus fumigatus), Candida species (Candida albicans, Candida parapsilosis, Candida glabrata) and Mucorales were the etiologic agents of infections. Caspofungin and luliconazole were effective antifungal agents for isolated fungi. The rate of mortality in infected patients suffering from proven and probable infections was 15.4% (6/39 cases).

Conclusion: Due to the high mortality rates of fungal infections in pediatrics, it is essential to identify modifiable risk factors, and implement control measures along with early detection techniques in pediatric populations.

Background and objectives: BK polyomavirus (BKPyV) poses a significant threat to kidney transplant (KT) recipients due to immunosuppression, leading to BK-associated nephropathy (BKVN) and reduced transplant survival. This study aimed to determine the prevalence of BKPyV among kidney transplant recipients in Jordan and to evaluate the association between BKPyV activity and kidney transplant outcomes.

Materials and methods: A retrospective observational study was conducted at the Jordanian Royal Medical Services Hospital (JRMS) from 2021 to 2024. Blood samples (n=157) from kidney transplant recipients were collected, and quantitative real-time PCR was performed to detect BKPyV DNA.

Results: The prevalence of BKPyV infection among kidney transplant recipients was 40.8% (n=64). Transplant failure occurred in 36% of cases (n=57), with BKPyV-DNA viremia observed in 74% of those with transplant failure (n=42). The prevalence of infection was significantly higher in patients under 18 years of age (81%, p<0.001) and in males (72%, p<0.001). BKPyV infection increased the odds of transplant failure tenfold.

Conclusion: In Jordan, the prevalence of BKPyV among kidney transplant recipients is high, particularly in males and younger patients. BKPyV significantly increases the risk of kidney transplant failure. Other studies are needed to further elucidate the impact of BKPyV on kidney transplant rejection and complications.

Background and objectives: Helicobacter pylori, identified in 1982, remains a major cause of gastric infections. Despite extensive research, an ideal treatment regimen for its eradication is yet to be determined, with antibiotic resistance posing a significant challenge. This study, conducted at Mohammed VI University Hospital, aimed to evaluate and compare the effectiveness of different therapeutic protocols for H. pylori eradication.

Materials and methods: This 13-month retrospective descriptive study was conducted at the Microbiology Laboratory of Mohammed VI University Hospital in Oujda, Morocco, to evaluate patients suspected of H. pylori infection using the urea breath test.

Results: A total of 190 patients were included, with an overall eradication rate of 73%. Three therapeutic protocols were tested, and bismuth concomitant therapy showed the highest eradication rate at 82%, outperforming the other regimens.

Conclusion: These findings highlight the importance of combining antimicrobial agents with antisecretory treatments to enhance eradication outcomes. The study also emphasizes the need for novel treatment strategies, particularly in light of rising antibiotic resistance. Vonoprazan-based regimens appear to offer a promising alternative, especially in the absence of antibiotic sensitivity testing. Future research should focus on optimizing treatment protocols while preserving beneficial gut flora.