Iranian Journal of Microbiology最新文献

Background and objectives: Enterococcus faecalis is known as common pathogen for endodontic infections and cause secondary and refractory pulp periapical periodontitis. The bacteria can opportunistically colonize periodontal pockets and presents a possibility of infection developing in other organs. This research will investigate the dissemination of E. faecalis from the gingival tissue to the heart and kidney.

Materials and methods: Three groups were formed, consisting of twelve male Sprague Dawley rats: a control group designated as 0-day, and experimental groups labeled as 7-days and 14-days. Periodontitis induced by concurrent infection with sterile wire 0.2 mm insertion and E. faecalis inoculation is performed into the gingival sulcus located between the maxillary right 1^st and 2^nd molar teeth area. After euthanasia, tissue samples around the maxillary gingiva, maxillary jaw samples, kidney and heart tissues were obtained for quantitative Real-Time PCR assay and histopathological analysis.

Results: Results showed at 7-days, there was an upregulation of E. faecalis gene expression in the gingiva, heart, and kidney samples as well as infiltration of the inflammatory cells at 7-days post induction, which consequently decreased at 14-days.

Conclusion: Thus, the study suggests dissemination of E. faecalis from gingival tissue to the heart, kidney which could be probable link between periodontal disease, heart, and kidney disease.

Background and objectives: Leptospirosis is a zoonotic disease caused by pathogenic Leptospira serovars. The genus Leptospira cannot differentiated by conventional techniques. However, identity determination of pathogenic serovar is precious of public health problems and epidemiological studies. Pulsed-field gel electrophoresis facilitates rapid identification of Leptospires to the serovar levels.

Materials and methods: In this study, we employed PFGE to evaluate 28 Leptospira isolates, with animal, human and environmental origin, obtained from Razi Vaccine and Serum Research Institute of Karaj, Iran. PFGE patterns of 28 Leptospira serovars were generated using the Not I restriction enzyme in comparison with the lambda ladder.

Results: Out of 28 serovars evaluated, we identified 22 different pulsed types, designated P1-P22. Out of 22 pulse groups, 3 were found to be a common type, but others were a single Type. Groups consisting of the common type were P3, P9, P14, and P16. The results showed that the discriminatory index of PFGE by Not I enzyme was 0.99, demonstrating heterogeneous differentiation among serovar members.

Conclusion: The PFGE methodology used in this study showed excellent interlaboratory report usability, rapid, reliable, enabling standardization and data sharing between laboratories.

Background and objectives: Escherichia coli O157: H7 is one of the most important causes of hemorrhagic colitis, and hemolytic uremic syndrome. The present study aimed to isolate E. coli O157: H7 from foods and patients with hemorrhagic colitis, and identify Shiga toxin genes, phylogenetic comparison, and antibiotic resistance of the isolates.

Materials and methods: In total 400 samples, including patients stool and food were taken in Isfahan-Iran province. Phenotypic tests and PCR were performed to identify Shiga toxin-producing E. coli. The isolated strains were compared phylogenetically by PFGE. Agar disk diffusion was performed to identify the antibiotic resistance of the isolates.

Results: Totally, 5 isolates of fecal samples were E. coli O157, but only 2 isolates carried H7 gene. Also, 9 isolates of E. coli O157 were isolated from food samples that 3 isolates were E. coli O157: H7. The isolates carried stx1, stx2, hlyA and eaeA genes. Also, E. coli non-O157: H7 identified from samples that contained stx1, stx2, hlyA genes. The highest susceptibility to imipenem and the highest resistance to ampicillin and ciprofloxacin were observed. There was a similarity of 100% between the E. coli O157: H7 strains isolated from patients and raw milk and minced beef samples.

Conclusion: Serotypes other than the O157 of E. coli are more prevalent in patients and food. The E. coli O157: H7 isolates from patients had 100% genetic similarity with minced meat and cow milk isolates, which indicates cattle are the most important reservoir of this bacterium in Iran.

Background and objectives: Bloodstream infection (BSI) is defined by the presence of viable microorganisms in the bloodstream. BSI is one of the major causes of sepsis and subsequent adverse clinical outcomes all across the globe. The present study was undertaken to identify clinico-epidemio-microbiological variables associated with 30-day mortality in patients having BSI with WHO priority pathogens.

Materials and methods: The study was conducted at a public sector tertiary care institute in central India from April 2019 to March 2021. Blood samples collected from patients with clinical suspicion of sepsis, were processed by automated bacterial culture system and interpreted as per CLSI guidelines. Calculated sample size was 150. Data was analyzed by R software.

Results: Respiratory tract infection was the most common source (43.3%) of BSI, followed by the gastrointestinal (20%) and urinary tract (18.7%). Among the patients, 33% required invasive mechanical ventilation, and 31% required inotropes. Diabetes mellitus (DM) was the most common co-morbidity (34%). The incidence of multi-drug resistant organisms (MDRO) was 59.3%. Escherichia coli was the most commonly (24%) isolated organism, followed by Klebsiella pneumoniae (17.3%) and Acinetobacter baumannii (16%).

Conclusion: Higher age, higher qSOFA score / SIRS score / mean SOFA score at presentation had higher mortality. Use of mechanical ventilation and inotropes during treatment and isolation of critical category organisms of WPP and multi drug resistant organisms were independent 30-day mortality predictors.

Background and objectives: The main cause of mortality in burn patients is infection from burns. Drug-resistant bacteria are the main causes of wound infection, so alternative antibiotic therapies hold significant importance. The objective of this study was to examine the impact of a collagen hydrogel that contains a nanoemulsion of Lavandula essential oil on the healing process of infected burn wounds.

Materials and methods: In this experimental study, 20 rats were randomly divided after applying burns with a 10 mm diameter hot plate and infecting the wounds with multidrug-resistant Pseudomonas aeruginosa into four groups, including a positive control, a negative control, the first experiment (collagen hydrogel), and the second experiment (collagen hydrogel containing Lavandula essential oil nanoemulsion). On the 4^th, 11^th, and 18^th days, tissue samples were taken for pathology studies. The important parameters in burn wound healing with hematoxylin and eosin and Masson's trichrome staining methods were investigated and scored according to Abramov's method.

Results: Based on the pathology findings, experimental groups 1 and 2 compared to the negative and positive control groups were effective in rat infection wound healing. The hydrogel scaffold in the experimental groups increased fibroblasts and angiogenesis compared to the control groups. Epithelization was noticed only in the hydrogel group containing nanoemulsion.

Conclusion: The study findings suggest that the use of collagen hydrogel with Lavandula essential oil nanoemulsion has potential as a wound dressing. This is because it has the potential to effectively promote healing and act as an antibacterial agent to prevent infections.

Background and objectives: During the coronavirus pandemic, the overuse of antibiotics to reduce coinfections and mortality may be contributing to the rise of antimicrobial resistance. In this study, we aim to investigate the antibiotic resistance changes of Acinetobacter baumannii post-COVID-19 pandemic in Northern Iran.

Materials and methods: The current study is a cross-sectional study. Between 2022 and 2023, 2190 clinical samples were collected from patients with healthcare-associated infections (HAIs) at four hospitals in Sari, which served as corona centers after the COVID-19 pandemic. Antimicrobial sensitivity was determined using standard broth macro-dilution, and resistance genes were detected using multiplex PCR.

Results: Based on the results co-amoxiclav had a resistance rate of 100%, while piperacillin/tazobactam showed the least resistance rate of 29.82%. In terms of GM MIC values, colistin was the most potent against multi-drug resistant isolates. The frequency of bla _OXA-51 , ampC, aphA6, and bla _NDM genes were 100%, 99.12%, 90.35%, and 69.30% respectively.

Conclusion: Our study revealed high multi-drug resistance rates. Piperacillin/tazobactam recommended for treating multi-drug resistant Acinetobacter baumannii infections in Northern Iran.

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.