Evaluation of ethanol and EDTA concentrations in the expression of biofilm-producing smf-1, rpfF genes in XDR clinical isolates of Stenotrophomonas maltophilia.

BACKGROUND: Stenotrophomonas maltophilia is able to cause infections in immunocompromised patients, and the treatment of this opportunistic pathogen is complicated due to its virulence factors, antibiotic resistance, and the ability of the bacteria to produce biofilm. The main goals of this study were to assess the susceptibility of extensively drug-resistant (XDR) isolates to ethanol and EDTA, and evaluating the synergistic effect of these disinfectants, and also survey the effect of exposure to sub-inhibitory concentrations of ethanol and EDTA on the expression of biofilm-producing smf-1, rpfF genes. RESULTS: The results showed that EDTA significantly increased the effectiveness of the ethanol and have a synergistic effect. All of the 10 XDR isolates included in the current study harbored smf-1 and rpfF genes and produced biofilm. After exposure to MIC, sub-MIC, synergism, and sub-synergism of ethanol and EDTA, the expression of smf-1 and rpfF genes was repressed significantly. CONCLUSION: In the current study, it was indicated that the expression of biofilm-producing genes was repressed when bacteria are exposed to different concentrations of ethanol and EDTA. Future studies should include more complex microbial communities residing in the hospitals, and more disinfectants use in hospitals. Expression of other virulence genes in different conditions is suggested.

Immunomodulatory effects of live and UV-killed Bacillus subtilis natto on inflammatory response in human colorectal adenocarcinoma cell line in vitro.

Background and Objectives: Colorectal cancer (CRC) is a heterogeneous disease of the colon or rectum arising from adenoma precursors and serrated polyps. Recently, probiotics have been proposed as an effective and potential therapeutic approach for CRC prevention and treatment. Probiotics have been shown to alleviate inflammation by restoring the integrity of the mucosal barrier and impeding cancer progression. Materials and Methods: In this study, we aimed to investigate the immunomodulatory effects of live and UV-killed Bacillus subtilis natto on the inflammatory response in CRC. Caco-2 cells were exposed to various concentrations of live and UV- killed B. subtilis natto, and cell viability was assessed using MTT assay. Gene expression analysis of IL-10, TGF-ß, TLR2 and TLR4 was performed using RT-qPCR. Results: Our findings showed that both live and UV-killed B. subtilis natto caused significant reduction in inflammatory response by decreasing the gene expression of TLR2 and TLR4, and enhancing the gene expression of IL-10 and TGF-ß in Caco-2 cells as compared to control group. Conclusion: The results of this study suggest that live and UV-killed B. subtilis natto may hold potential as a therapeutic supplement for modulating inflammation in CRC.

A Systematic Review and Meta-Analysis of Aeromonas-Associated Diarrhea Among Children in Asia.

Background: Diarrheal illness is a prominent public health worry in developing countries, resulting in high mortality among children. Sociodemographic characteristics and geographic settings are the main effective factors for the increased incidence of childhood diarrhea. Aeromonas is a neglected organism capable of causing dysentery and diarrhea. The aim of this systematic review and meta-analysis was to determine the prevalence of Aeromonas as an agent in the causation of diarrhea in Asian children. Methods: We conducted a systematic review using Web of Science, PubMed, Wiley Online Library, Science Direct, and Google Scholar for peer-reviewed articles published between January 2000 and February 2023. We considered studies that found Aeromonas in diarrheal stool. A random-effects model was used to determine the pooled prevalence of Aeromonas. Results: Our search returned 2,057 articles, with 17 articles from seven Asian nations being included in the systematic review. The pooled prevalence of Aeromonas was 4.5% (95% confidence interval [CI]: 2.9%-6.8%), with heterogeneity (I2 = 96.85; p < 0.001). There was a greater prevalence in areas with high population living in poverty (12.2%; 95% CI: 5.8%-24%) and lower-middle-income countries (5.0%; 95% CI: 2.7%-9.0%). In addition, the prevalence of Aeromonas was greater in South Asia (10.0%; 95% CI: 5.6%-17.2%), in India (12.9%; 95% CI: 6.8%-23%), and in countries with open defecation rate of 5%-25% (11.3%; 95% CI: 6.3%-19.2%). Conclusion: The prevalence of Aeromonas-associated diarrhea in children in Asia estimated in the present study highlighted the high burden of Aeromonas in some parts of Asia.

Probable vector of Crimean-Congo hemorrhagic fever virus; Hyalomma aegyptium: a systematic review and meta-analysis.

Introduction: Crimean-Congo hemorrhagic fever (CCHF) is the widest emerging severe viral tick-borne disease affecting humans. Crimean-Congo haemorrhagic fever virus (CCHFV) circulates by routine enzootic tick-vertebrate hosts-tick transmission cycles. We aimed to evaluate the molecular prevalence of CCHFV in ticks on a global scale. Methods: A systematic procedure was used to perform this review and meta-analysis using PubMed, Google Scholar, and Web of Science databases from 1 January 2000 through 12 April 2023. Of the 2310 papers identified, 43 articles met the inclusion criteria for this study. Results: The overall prevalence of CCHFV was 4.0% (95%CI: 2.7-6.0%) in ticks on the global scale, with heterogeneity (I2=96.387; p=0.0001). The genus Hyalomma was shown as the most frequent tick infected with CCHFV 5.4% (95%CI: 3.3-8.7%). We found that the pooled prevalence of CCHFV was higher in Hyalomma aegyptium 27.6% (95%CI: 22.7-33.2%). The pooled prevalence was higher in Asia 5.1% (95%CI: 3.3-7.7%), and Spain 21.0% (95%CI: 3.4-66.9). The locations with annual rainfall of 401-1000 mm 6.1% (95%CI: 2.6-13.5%) and latitude of 31-40° 6.0% (95%CI: 4.1-8.9%) were associated with the greatest pooled prevalence of CCHFV in ticks. Conclusions: Surveillance of CCHFV in ticks will give a better comprehension for the future implementation of public health interventions. The question of whether Hyalomma aegyptium is a plausible or certain vector should be the subject of further investigation.

Frequency of Multi-Drug Resistance and Molecular Characteristics of Resistance to Colistin in Acinetobacter baumannii Collected from Patients in Intensive Care Units with Ventilator-Associated Pneumonia.

Background: Acinetobacter baumannii is one of the most common causes of ventilator-associated pneumonia (VAP) in patients hospitalized in ICU. Multiple resistance has resulted in excessive use of Colistin antibiotic, which is the latest treatment option for this bacterium. Therefore, the purpose of this study was to determine the abundance of multi-resistance and molecular characteristics of resistance to colistin among A. baumannii isolated from patients that are infected with VAP and hospitalized in ICU of "Qazvin" and "Masih Daneshvari" hospitals. Materials and Methods: In this study, 200 A. baumannii isolates related to VAP were collected from ICU of "Masih Daneshvari" (2012-2018) and "Qazvin" (2017-2018) hospitals, from bronchoalveolar lavage & tracheal aspirate specimens. Isolates were detected as A. baumannii by PCR with specific primers of the blaOXA-51-like gene. Antibacterial susceptibility of isolates to colistin was determined by the MIC method, and other antibiotics were examined by the disk diffusion method, according to the CLSI criteria. Multi-drug resistance (MDR) and extended-drug resistance (XDR) isolates were determined according to standard definitions of the CLSI. Results: All the isolates were susceptible to colistin. Moreover, they were resistant to piperacillin, piperacillin-tazobactam, ceftazidime, cefotaxime, ceftriaxone, amikacin, gentamycin, levofloxacin, co-trimoxazole, and ciprofloxacin. Antimicrobial resistance rates for tetracycline and ampicillinsulbactam were 8.5% and 20%, respectively. All isolates were MDR and XDR. All isolates were susceptible to colistin (MIC50=1 and MIC90=2 µg/ml). The sequencing results did not show any point mutation in pmr CAB genes, and mcr-1 gene was not detected in any isolates. Conclusion: In this study, all A. baumannii isolates collected from VAP patients were MDR and XDR. Although all isolates were susceptible to colistin, and this agent seems the most appropriate antibiotic for treatment of VAP, colistin resistance can become endemic in the world rapidly due to plasmid-mediated mobile colistin resistance mcr genes.

Distribution of smf-1, rmlA, spgM and rpfF genes among Stenotrophomonas maltophilia isolates in relation to biofilm-forming capacity.

OBJECTIVES: The molecular mechanisms involved in biofilm formation inStenotrophomonas maltophilia are poorly understood. Here, we examined whether the presence of smf-1, rmlA, spgM and rpfF genes is associated with biofilm formation and antibiotic resistance in S. maltophilia. METHODS: A total of 150 S. maltophilia isolates were collected from three tertiary-care hospitals in Iran and were identified through PCR amplification of the 23S rRNA gene. Biofilm formation was determined by microtitre plate assay. Presence of smf-1, rmlA, spgM and rpfF genes was examined by PCR. RESULTS: Among the isolates examined, 148 (98.7%) were able to produce biofilm, of which 69 (46.0%) were strong biofilm-producers, whereas 32 (21.3%) and 47 (31.3%) were moderate and weak biofilm-producers, respectively. The frequency ofsmf-1, rmlA, spgM and rpfF was 99.3%, 98.0%, 97.3% and 70.0%, respectively. Statistical analysis indicated a direct correlation between presence of the rpfF gene and biofilm formation (P < 0.001). The high prevalence of smf-1 (99.3%) among the isolates is noted and there was a significant association between smf-1 and biofilm-forming ability (P < 0.01), but lower than rpfF. Additionally, a direct association was found between resistance to ticarcillin/clavulanate, ceftazidime, ciprofloxacin and doxycycline and strong biofilm formation in the S. maltophilia isolates (P < 0.01). CONCLUSION: This study demonstrated thatS. maltophilia clinical isolates significantly differ in biofilm-forming ability. Moreover, presence of rpfF and smf-1, but not spgM, could be associated with biofilm formation. This study highlights the importance of rpfF in formation of biofilm compared with the other genes involved.

Development and evaluation of a Quadruplex Taq Man real-time PCR assay for simultaneous detection of clinical isolates of Enterococcus faecalis, Enterococcus faecium and their vanA and vanB genotypes.

BACKGROUND AND OBJECTIVES: We developed and evaluated the utility of a quadruplex Taqman real-time PCR assay that allows simultaneous identification of vancomycin-resistant genotypes and clinically relevant enterococci. MATERIALS AND METHODS: The specificity of the assay was tested using reference strains of vancomycin-resistant and susceptible enterococci. In total, 193 clinical isolates were identified and subsequently genotyped using a Quadruplex Taqman real-time PCR assay and melting curve analysis. Representative Quadruplex Taqman real-time PCR amplification curve were obtained for Enterococcus faecium, Enterococcus faecalis, vanA-containing E. faecium, vanB-containing E. faecalis. RESULTS: Phenotypic and genotypic analysis of the isolates gave same results for 82 enterococcal isolates, while in 5 isolates, they were inconsistent. We had three mixed strains, which were detected by the TaqMan real-time PCR assay and could not be identified correctly using phenotypic methods. CONCLUSION: Vancomycin resistant enterococci (VRE) genotyping and identification of clinically relevant enterococci were rapidly and correctly performed using TaqMan real-time multiplex real-time PCR assay.