Protective effects of different lyoprotectants on survival of clinical bacterial isolates in a hospital biobank.

Nowadays the significant role of biobanks in medical, diagnostic, industrial, and environmental research is well known. Bacterial biobanks could be used as a good resource for designing new treatments, biomedical and industrial researches, and laboratory diagnostics. To have a collection of bacteria from clinical samples and maintain their long-term viability, their preservation needs appropriate protective agents, like cryoprotectants and lyoprotectants. In this study, we collected and characterized Gram-negative and Gram-positive bacteria carrying important antibiotic resistance markers from different clinical samples of hospitalized children. Sucrose (10%), skimmed milk (10%), skimmed milk plus sodium glutamate (10% + 1%), and bovine serum albumin (BSA, 10%) were used as lyoprotectants during the freeze-drying procedure. The survival rate of the lyophilized samples was calculated by dilution plating and measuring the colony forming unit (CFU) after 3 months of storage. The culture analysis results indicated that 25 of the 27 studied bacterial genera (Dilutions 10-3 to 10-6), including Shigella, Methicillin-resistant S. aureus, Acinetobacter spp., Escherichia spp., Pseudomonas spp., Klebsiella spp., Enterococcus spp., were recovered in cultured fractions from all preservation conditions, while 2 genera were only detected in a single preservation condition (2/27, 7.4%). Based on the results, sucrose (10%) and skimmed milk (10%) presented the most protective features. The survival rates varied significantly according to types of the bacteria. Collectively, our results showed a diversity in the recovery of different bacterial genera after lyophilization. While statistically no significant difference was detected among the studied protective agents, sucrose (10%) and skimmed milk (10%) exhibited more effective lyoprotective properties for both Gram-positive and Gram-negative bacteria among the clinical isolates in our study.

Multicenter Study of Rotavirus Infection, Diversity of Circulating Genotypes and Clinical Outcomes in Children ≤5 Years Old in Iran.

BACKGROUND: To determine the epidemiology of rotavirus group A (RVA) infection in symptomatic children, and analyze genotype diversity in association with clinical characteristics, geographical and seasonal changes. METHODS: The stool samples of symptomatic children 5≥ years old were collected from 5 different hospitals during December 2020 and March 2022. Rotavirus stool antigen test was done and G and P genotypes of the positive samples were determined. Associations of the infection and genotype diversity with demographical and clinical data were assessed by statistical methods. RESULTS: RVA infection was detected in 32.1% (300/934) of the patients (Ranges between 28.4% and 47.4%). An inverse association with age was detected, where the highest frequency was measured in children ≤12 months of age (175/482, 36.3%). The infection was more frequent during winter (124/284, 43.7%) and spring (64/187, 34.2%). Children who were exclusively fed with breast milk showed a lower rate of infection (72/251, 28.6%). Among the 46 characterized genotypes (17 single- and 29 mixed-genotype infections), G1P[8] and G9P[4] were more frequently detected in children <36 (67/234, 28.63%) and 36-60 (7/24, 29.16%) months of age children, respectively. A seasonal diversity in the circulating genotypes was detected in different cities. Children with G1P[8], G1P[6], and mixed-genotype infection experienced a shorter duration of hospitalization, and a higher frequency of nausea and severe diarrhea, respectively. CONCLUSIONS: In this study high frequency of RVA infection was detected in symptomatic children in Iran. Moreover, genotype diversity according to geographic area, seasons, age groups, and clinical features of disease was detected.

Transcriptional alteration of NF-κB-associated long noncoding RNAs in the stomach of Helicobacter pylori-infected and non-infected patients.

INTRODUCTION: Helicobacter pylori could colonize the gastric mucosa and cause gastritis, ulcers and cancer. Numerous virulence factors have been identified in this bacterium that play important roles in promoting gastric disorders. Although the interaction of long noncoding RNAs (lncRNAs) with transcription, processing, and translation of genes associated with different diseases are described, their interaction with the inflammatory genes and H. pylori infection in the gastric tissue is not well known. This study compared changes in common NF-κB-regulatory lncRNAs in the gastric tissue of H. pylori-infected and non-infected patients with gastritis. Moreover, a link between the virulence entity of the strains and the transcriptional changes was analyzed. METHODOLOGY: Two groups of infected and non-infected patients with chronic gastritis were included in the study. Genotyping of the H. pylori strains was done by PCR and relative changes in the expression of NF-κB and regulatory lncRNAs, lincRNA-p21, MALAT1, NKILA, were measured by relative quantitative real time-PCR. RESULTS: Transcriptional levels of MALAT1, lincRNA-p21, and NKILA genes decreased in the infected patients compared with the non-infected patients, which was significantly linked with increased NF-κB gene expression. Our results showed that a hypervirulent strain of H. pylori with oipA"on"/HP-NAP+/iceA1+/iceA2+/vacA s1m1/s1m2+/cagA+ genotype can promote a higher level of NF-κB transcription in the inflamed tissue. CONCLUSIONS: H. pylori infection could promote down-regulation of lincRNA-p21, MALAT1 and NKILA in the infected gastric tissue in correlation with NF-κB upregulation. More detailed studies are needed to show a link between the virulence genes and their impact on the regulation of lncRNAs in the stomach.

Microbiome analysis of bile samples in patients with choledocholithiasis and hepatobiliary disorders.

Introduction: The involvement of bacteria in the pathogenesis of biliary tract disease is largely unknown. In this study, we investigated the microbiota of the biliary tissue among adult patients with choledocholithiasis during endoscopic retrograde cholangiography (ERCP). Methods: 16S rDNA sequencing of bile samples, culture, and data of the medication history, underlying diseases, and liver function tests were used for the interpretation of differences in the composition of detected bacterial taxa. Results: The four most common phyla in the bile samples included Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Infection with anaerobic and microaerophilic bacteria showed host specificity, where Fusobacterium, Prevotella, Veillonella, Propionibacterium, Gemella, and Helicobacter coexist in the same patients. Clostridium and Peptoclostridium spp. were detected in 80% and 86% of the patients, where the highest relative abundance rates were detected in patients with elevated alkaline phosphatase (ALP) levels and leukocytosis, respectively. Higher diversity in the bacterial population was detected in patients with common bile duct (CBD) stone, in which the richness of an unclassified member of Alphaproteobacteria plus Helicobacter, Enterobacter/Cronobacter spp., Sphingomonas, Prevotella, Fusobacterium and Aeromonas were detected. Conclusions: Our findings suggested correlations between the presence and relative abundance of several bacterial taxa and CBD stone formation and the effect of medication and underlying diseases on the bile microbial communities. A study on a higher number of bile samples from patients compared with the control group could reveal the role of these bacteria in the pathogenesis of biliary tract disease.

Molecular study on virulence and resistance genes of ST131 clone (uropathogenic/enteropathogenic Escherichia coli) hybrids in children.

Aim: To analyze ST131 clones and other characteristics in uropathogenic and atypical enteropathogenic Escherichia coli hybrids. Methods: Samples were collected from children with urinary tract infections and underwent testing for antimicrobial susceptibility, multidrug resistance and extended-spectrum ß-lactamases, in vitro biofilm formation and virulence, resistance genes, hybrid pathotypes and ST131 clones. Results: E. coli isolates showed high levels of antibiotic resistance, extended-spectrum ß-lactamase production, virulence genes, multidrug resistance and biofilm formation. Four (5.0%) isolates were identified as uropathogenic/atypical enteropathogenic E. coli hybrids, all of which belonged to the high-risk ST131 clone. Conclusion: Our results provide promising insights about hybrid isolates and should be addressed to improve prevention measures for hybrid pathotypes.

Evaluation of Covid-19 anti-spike IgG antibody five months after the second Covid-19 vaccination.

Background: Studies in different communities have shown significant differences in IgG antibody titers in the time period after the first and second doses of the vaccines. This study aimed to serologically evaluate the IgG anti-spike antibody titer five months after injection of the second COVID-19 vaccine in healthcare workers. Materials and method: This study was performed in healthcare personnel for whom five months had passed since their second anti-Covid-19 vaccination. The level of IgG antibody against SARS-CoV-2 spike protein was measured by ELISA. Healthcare workers in Mofid Children's hospital received three brands of vaccines: Sputnik V, Sinopharm, and AstraZeneca. Results: The mean titer of anti-spike IgG was 4.3±2.29 units. The percentage of positive cases of the antibody was estimated to be 96.4%. The titer of anti-spike IgG antibody was dependent on both the occupational area and a positive history of Covid-19 disease. Conclusion: About 96.4% of the staff vaccinated against Covid-19 had a high titer of anti-spike IgG antibody even five months after inoculation of the second dose. The field of occupational can affect the level of antibody present.

Activation of the DNA damage response pathway in the infected gastric tissue with Helicobacter pylori: a case-control study.

INTRODUCTION: Gastritis is among the most common human diseases worldwide. Although the involvement of Helicobacter pylori infection as a class I human carcinogen for gastric cancer progression is accepted, it is not well known how gastritis progression to atrophy and stomach cancer occurs. In this case-control study, the potential link of H. pylori infection with alteration in the transcription of genes involved in DNA Damage Response pathways was investigated among the patients with gastritis. METHODOLOGY: To measure the difference in the relative mRNA expression level of ATM, CHEK2, TP53, DCLRE1C, POLM, and XRCC4 genes between H. pylori-infected and non-infected patients, gastric biopsies of 30 H. pylori infected patients with moderate chronic gastritis and 30 non-infected patients with mild chronic gastritis were analyzed. RESULTS: Up-regulation of genes linked to non-homologous end joining (NHEJ) pathway (DCLRE1C, POLM, and XRCC) was shown in 40% (8.44 fold ± 13.91), 63.33% (15.72 fold ± 33.08) and 50% (9.99 fold ± 21.55), respectively, and also to DDR pathway (ATM, CHEK2, and TP53) in 33% (2.42 fold ± 3.17), 40% (2.86 fold ± 3.61) and 50% (5.00 fold ± 6.52), respectively. No correlation was detected between alteration in the transcription level of the studied genes and age or gender. CONCLUSIONS: Our results provide new data that may support the potential involvement of H. pylori infection in the activation of genes involved in DNA damage response, mainly through a non-homologous end-joining DNA repair system that might be linked to mutagenesis in the pre-cancerous gastric tissue.

Shigella Flexneri Serotypes: O-antigen Structure, Serotype Conversion, and Serotyping Methods.

Shigella flexneri is the most common cause of shigellosis in developing countries. Up to now, 23 serotypes of S. flexneri have been reported. Different serotypes result from the addition of acetyl, glucosyl, or phosphatidylethanolamine groups on the O-antigen backbone and horizontal transfer of mentioned groups can lead to serotype conversion among S. flexneri strains. Serotype conversion causes either a circulation of pre-existing serotypes or is responsible for the emergence of new serotypes. Serotype conversion plays a pivotal role in the protection and evasion of S. flexneri from the host immune response. Furthermore, spreading any new serotype can provide evolutionary advantages. Hence, information about S. flexneri O-antigen structure, serotype conversion, and serotyping methods can be helpful to understand the disease that attributes distinct serotypes in order to apply control or prevention methods in accordance with predominant serotypes over the course of time. Thus, the scope of this review is to give an overview of the serotype structures, factors involved in O-antigen modification, molecular analysis, and epidemiological evidence for the benefits of serotype conversion for S. flexneri serotypes. We are also providing a review of the typing methods.

Transcriptional analysis of Helicobacter pylori cytotoxic-associated gene-pathogenicity island in response to different pH levels and proton pump inhibitor exposure.

BACKGROUND: Long-term use of proton pump inhibitors (PPIs) can increase the risk of gastric cancer in Helicobacter pylori-infected patients; nevertheless, there is no data about their impact on the pathogenicity of H. pylori. This study aimed at investigating the transcriptional alteration of key gene mediators of cytotoxin-associated gene-pathogenicity island (cag-PAI) among clinical H. pylori isolates in response to omeprazole at different pH levels. METHODS: Accordingly, H. pylori isolates with the same virulence genotypes selected from the gastric biopsies of patients and transcriptional alteration in the cag-PAI genes studied in the presence or absence of omeprazole (2 mg/mL) at pH 2.0, 4.0 and 7.0 after 30 and 90 minutes of the treatment. Relative changes in the transcriptional levels were recorded in each assay, separately. RESULTS: Of 18 H. pylori isolates, the cag-PAI empty site was detected in four strains, while the presence of cagA, cagL and cagY was characterized in 77.7%, 83.3% and 83.3% of the cag-PAI-positive strains, respectively. Transcriptional analysis of the selected strains showed up-regulation of cagA and cagL, mainly at pH 2.0 and 4.0 after 30 and 90-minute exposure. A diversity in the expression levels of cag-PAI genes was seen among the strains at the extent and time of induction. CONCLUSION: Our results showed that omeprazole could increase the expression of H. pylori cagA and cagL at acidic pH. Heterogeneity among the strains probably has an impact on the extent of their interplay with PPIs. Further studies are needed to establish this correlation.

Endogenous Bacteremia Caused by Intestinal Colonization of Carbapenem-Resistant Enterobacteriaceae (CRE) in Immunocompromised Children.

OBJECTIVE: Carbapenem-resistant Enterobacteriaceae (CRE) infection is life-threatening, especially for immunocompromised children. The source tracking of CRE could prevent bacteremia during hospitalization. In this study, the intestinal colonization of CRE and their translocation to blood were investigated. METHODS: Stool samples from immunocompromised pediatric patients were collected after admission, and secondary stool and blood samples were collected in case of fever. After CRE phonotypic detection, the OXA-48, NDM-1, VIM, IMP, and KPC genes were detected by PCR. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) was used to determine the phylogenic relatedness of the blood and fecal isolates. RESULTS: Bacteremia was recorded in 71.4% of the patients. Enterobacteriaceae spp. were recorded in 100% of the stool samples and 31% of the blood samples. The correlation between the length of stay (LOS), days of fever, chemotherapy regimens, and death rate was significant (p-value ≤ 0.05). OXA-48 was present in all CRE isolates in both the primary and the secondary stool samples and the blood samples. According to the phylogenetic data, 58.33% of the patients with bacteremia had identical blood and stool isolates. The death rate was 24.4% in children with CRE bacteremia. CONCLUSIONS: The primary intestinal colonization with CRE in immunocompromised pediatrics and their translocation to blood was established in this study. The implementation of infection control programs and the application of infection prevention strategies for immunocompromised children is necessary.

The intestinal carrier status of Enterococcus spp. in children: clonal diversity and alterations in resistance phenotypes before and after admission to a pediatric intensive care unit.

BACKGROUND: This study aimed to investigate the intestinal carrier status of Enterococcus spp. among children in a pediatric intensive care unit (PICU) and reveal the role of hospitalization in the alteration of resistance phenotypes and clonal diversity of the isolates during admission and discharge periods. METHODS: Two separate stool samples were collected from hospitalized patients in the pediatric intensive care unit at admission and discharge times. The culture was done, and Enterococcus species were tested for antimicrobial susceptibility and carriage of vanA-D gene subtypes. Random Amplified Polymorphic DNA (RAPD)-PCR was used for a phylogenetic study to check the homology of pairs of isolates. RESULTS: The results showed carriage of Enterococci at admission, discharge, and at both time points in 31%, 28.7%, and 40.1% of the cases, respectively. High frequencies of the fecal Enterococcus isolates with vancomycin-resistance (VR, 32.6% and 41.9%), high-level of gentamicin-resistance (HLGR, 25.6% and 27.9%), and multi-drug resistance phenotypes (MDR, 48.8% and 65.1%) were detected at admission and discharge times, respectively. Resistance to vancomycin, ampicillin, and rifampicin was higher among E. faecium, but resistance to ciprofloxacin was higher in E. faecalis isolates. The increased length of hospital stay was correlated with the carriage of resistant strains to vancomycin, ampicillin, and ciprofloxacin. While the homology of the isolates was low among different patients during hospitalization, identical (9%) and similar (21%) RAPD-PCR patterns were detected between pairs of isolates from each patient. CONCLUSIONS: The high rate of intestinal carriage of VR, HLGR-, and MDR-Enterococci at admission and during hospitalization in the PICU, and the impact of increased length of hospital stay on the fecal carriage of the resistant strains show the importance of antibiotic stewardship programs to control their transmission and spread in children.

Effectiveness of mouthwashes on reducing SARS-CoV-2 viral load in oral cavity: a systematic review and meta-analysis.

BACKGROUND: The risk of SARS-COV-2 transmission is relatively high during dental procedures. A study was conducted to investigate the effects of mouthwashes on SARS-COV-2 viral load reduction in the oral cavity. METHODS: A systematic search was performed in PubMed, EMBASE, Scopus, Web of Science, and Cochrane library for relevant studies up to 20 July, 2022. Randomized and non-randomized clinical trial and quasi-experimental studies evaluating patients with Covid-19 infection (patients) who used mouthwashes (intervention) compared to the same patients before using the mouthwash (comparison) for reducing the SARS-COV-2 load or increasing the cycle threshold (Ct) value (outcome) were searched according to PICO components. Three independent reviewers conducted literature screening and data extraction. The Modified Downs and Black checklist was used for quality assessment. A meta-analysis was performed with a random effects model in the Revman 5.4.1software using the mean difference (MD) of cycle threshold (Ct) values. RESULTS: Of 1653 articles, 9 with a high methodological quality were included. A meta-analysis indicated that 1% Povidone-iodine (PVP-I) was an effective mouthwash for reducing the SARS-COV-2 viral load [MD 3.61 (95% confidence interval 1.03, 6.19)]. Cetylpyridinium chloride (CPC) [MD 0.61 (95% confidence interval -1.03, 2.25)] and Chlorhexidine gluconate (CHX) [MD -0.04 95% confidence interval (-1.20, 1.12)] were not effective against SARS-COV-2. CONCLUSION: Using mouthwashes containing PVP-I may be recommended for reducing the SARS-COV-2 viral load in the oral cavity of patients before and during dental procedures, while the evidence is not sufficient for such effects for CPC and CHX-containing mouthwashes.

Seroepidemiological and Molecular Survey for the Detection of SARS-CoV-2 Infection among Children in Iran, September 2020 to June 2021: 1-Year Cross-Sectional Study.

A population-based seroepidemiological and molecular survey on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was performed to detect induced antibodies to prior exposure and active infection of children aged 14 years or less in Tehran between 19 September 2020 and 21 June 2021. Moreover, correlations between the children's demographic data and coronavirus disease 2019 (COVID-19) symptoms with the infection status were investigated. Out of 1517 participants, cardinal symptoms of COVID-19 (fever > 38 °C and/or cough and/or diarrhea) were detected in 18%, and serological history of SARS-CoV-2 infection and polymerase chain reaction (PCR) positivity were confirmed in 33.2% and 10.7% of the weighted population, respectively. The prevalence of SARS-CoV-2 infection was significantly higher among 10-14-year-old children. Active infection was significantly higher in symptomatic children and during autumn 2020 and spring 2021. The quantitative reverse transcription real-time PCR (RT-qPCR) positivity was significantly higher among families with a lower socioeconomic status, whereas no association between RT-qPCR or seropositivity was determined with household size, underlying diseases, or gender. In conclusion, high SARS-CoV-2 infection prevalence and seroprevalence were detected in children in Tehran in different seasons. Infection prevalence was significantly higher in older children and in those with a positive history of close contact with infected cases and/or lower socioeconomic status.

Antibiotic resistance assessment and multi-drug efflux pumps of Enterococcus faecium isolated from clinical specimens.

INTRODUCTION: Enterococcus faecium is a major cause of community and hospital-acquired infections. Due to limited options for infection with fluoroquinolones-resistant Enterococci, novel therapeutics are urgently needed. Efflux pumps are contributed to fluoroquinolones resistance phenotype in this bacterium and novel inhibitors that target these efflux pumps could be effective in patients. In this research, the possible synergistic effect of an efflux pump inhibitor (EPI), thioridazine, with ciprofloxacin was investigated against clinical isolates of E. faecium. METHODOLOGY: A total of 88 isolates of E. faecium from clinical specimens were studied from August 2017 to September 2018. Conventional phenotypic and molecular methods characterized all the isolates. Standard susceptibility tests and molecular assays determined the antibiotic resistance profiles and the frequency of efflux pump genes. Minimum inhibitory concentrations (MICs) to ciprofloxacin (CIP) in the presence and absence of thioridazine were measured by the micro-broth dilution method. RESULTS: The highest antibiotic resistance rate among E. faecium isolates was related to ciprofloxacin (96.8%), levofloxacin (94.3%), and imipenem (90.9%), respectively. The highest frequency of efflux pump determinants was related to efmA (60, 68%), followed by emeA (48, 54.5%), and efrA and/or efrB genes (45, 51%). The efflux pump inhibitor showed ≥ 2-fold decrease in the MIC value of ciprofloxacin in 48.2% of the isolates. CONCLUSIONS: Efflux pump inhibitor genes efrAB, efmA, and emeA are common among the E. faecium clinical isolates. Our results supported the administration of thioridazine, as an efflux pump inhibitor, in fluoroquinolone-resistant E. faecium infections due to its synergistic effect with CIP.

Examining the effect of Helicobacter pylori cagPAI variety on gene expression pattern related to gastric cancer.

OBJECTIVES: We aimed to determine possible association between heterogeneity of Helicobacter pylori cytotoxin-associated gene pathogenicity island and gene expression profiles in patients with distinct histopathological changes. METHODS: Gastric biopsies were obtained from seventy five patients. Microbiological and pathological examinations were done and intactness of Helicobacter pylori cagPAI was determined by PCR using 11 pairs of primers flanking cagζ-cagA regions and cagPAI empty site. Alterations at mRNA levels of eight genes were investigated by real-time PCR and their association with cagPAI intactness and histopathological changes examined statistically. RESULTS: A larger proportion of cagPAI positive strains colonized patients with SAG (52.4%), followed by CG (33.3%), and IM (14.3%). Intact cagPAI was found in 87.5% of the strains obtained from patients with SAG, while significantly lower frequency was detected among those with CG (12.5%) and IM (0%). No significant difference was found among the studied histological groups and fold changes in gene expression of gastric biopsies of Helicobacter pylori infected patients with distinct cagPAI status. However, in each histological group, the strains with more complete gene cluster induced (ErbB2, CCNE1, CTNNB1, and MMP7 in SAG and IM groups) or reduced (TP53, in CG group) expression of the GC associated genes in relatively higher levels. APC, TP53 and E-cadherin were down-regulated in patients with SAG and IM compared with CG patients, irrespective to the status of cagPAI integrity. CONCLUSIONS: Helicobacter pylori strains that carry more complete cagPAI segment could induce remarkably higher levels of mRNA changes of GC associated genes in all histopathological groups.

Antibiotic Susceptibility Patterns for Carbapenem-Resistant Enterobacteriaceae.

Carbapenem is a broad-spectrum beta-lactam antibiotic considered the last choice for the treatment of antibiotic-resistant Gram-negative bacteria. Thus, the increasing rate of carbapenem resistance (CR) in Enterobacteriaceae is an urgent public health threat. This study aimed to evaluate the antibiotic susceptibility pattern of carbapenem-resistant Enterobacteriaceae (CRE) to new and old antibiotics. In this study, Klebsiella pneumoniae, E. coli, and Enterobacter spp. were collected from 10 hospitals in Iran for one year. CRE is recognized by resistance to meropenem and/or imipenem disk after identification of the collected bacteria. Antibiotic susceptibility of CRE against fosfomycin, rifampin, metronidazole, tigecycline, and aztreonam was detected by disk diffusion method and colistin by MIC. In this study, 1222 E. coli, 696 K. pneumoniae, and 621 Enterobacter spp. were collected from 10 hospitals in Iran in one year. Fifty-four E. coli (4.4%), 84 K. pneumoniae (12%), and 51 Enterobacter spp. (8.2%) were CRE. All CRE strains were resistant to metronidazole and rifampicin. Tigecycline has the highest sensitivity on CRE and levofloxacin for Enterobacter spp. Tigecycline showed an acceptable effectiveness rate of sensitivity on the CRE strain. Therefore, we suggest that clinicians consider this valuable antibiotic to treat CRE.

The genotypic and phenotypic characteristics contributing to high virulence and antibiotics resistance in Escherichia coli O25-B2-ST131 in comparison to non- O25-B2-ST131.

BACKGROUND: Escherichia coli serogroup O25b-sequence type 131 (E. coli O25-B2-ST131) is considered as multidrug-resistant and hypervirulent organism. There is lack of data about involvement of this pathogen in the children's infection. In this study, the prevalence, and clonality, virulence capacity, and antibiotic resistance phenotype and genotype of E. coli O25-B2-ST131 compared with non-O25-B2-ST131 isolates were investigated in children with urinary tract infection in Tehran, Iran. METHODS: The E. coli isolates from urine samples were identified using conventional microbiological methods. Characterization of E. coli O25-B2-ST131 clone, antibiotic susceptibility, biofilm formation, ESBLs phenotype and genotype, serum resistance, hemolysis, hydrophobicity, and formation of curli fimbriae were done using conventional microbiological and molecular methods. Clonality of the isolates was done by rep-PCR typing. RESULTS: Among 120 E. coli isolates, the highest and lowest antibiotic resistance was detected against ampicillin (92, 76.6%) and imipenem 5, (4.1%), respectively. Sixty-eight (56.6%) isolates were ESBL-producing and 58 (48.3%) isolates were considered as multi-drug resistance (MDR). The prevalence of ESBL-producing and MDR isolates in O25-B2-ST131 strains was higher compared with the non-O25-B2-ST131 strains (p value < 0.05). O25-B2-ST131 strains showed significant correlation with serum resistance and biofilm formation. Amongst the resistance and virulence genes, the prevalence of iucD, kpsMTII, cnf1, vat, blaCTX-M-15, and blaSHV were significantly higher among O25-B2-ST131 isolates in comparison with non-O25-B2-ST131 isolates (p value < 0.05). Considering a ≥ 80% homology cut-off, fifteen different clusters of the isolates were shown with the same rep-PCR pattern. CONCLUSIONS: Our results confirmed the involvement of MDR-ESBLs producing E. coli strain O25-B2-ST131 in the occurrence of UTIs among children. Source tracking and control measures seem to be necessary for containment of the spread of hypervirulent and resistance variants in children.

Assessment of early and post COVID-19 vaccination antibody response in healthcare workers: a multicentre cross-sectional study on inactivated, mRNA and vector-based vaccines.

In this multicentre study, we compared the status of antibody production in healthcare personnel (HCP) before and after vaccination using different brands of COVID-19 vaccines between March 2021 and September 2021. Out of a total of 962 HCP enrolled in our study, the antibody against the S1 domain of SARS-CoV-2 was detected in 48.3%, 95.5% and 96.2% of them before, after the first and the second doses of the vaccines, respectively. Our results showed post-vaccination infection in 3.7% and 5.9% of the individuals after the first and second doses of vaccines, respectively. The infection was significantly lower in HCP who presented higher antibody titres before the vaccination. Although types of vaccines did not show a significant difference in the infection rate, a lower infection rate was recorded for AstraZeneca after the second vaccination course. This rate was equal among individuals receiving a second dose of Sinopharm and Sputnik. Vaccine-related side effects were more frequent among AstraZeneca recipients after the first dose and among Sputnik recipients after the second dose. In conclusion, our results showed diversity among different brands of COVID-19 vaccines; however, it seems that two doses of the vaccines could induce an antibody response in most of HCP. The induced immunity could persist for 3-5 months after the second vaccination course.

Intestinal colonization of vancomycin-resistant Enterococcus in children admitted to Mofid children's hospital intensive care unit at admission and at discharge.

BACKGROUND: This study aimed to investigate the frequency of intestinal colonization by vancomycin-resistant Enterococcus (VRE) carrying vanA and vanB genes in patients at ICU admission and at discharge from ICU in Mofid children's Hospital, Tehran, Iran. METHOD: Sampling was performed using rectal swabs and vancomycin susceptibility testing for Enterococcus spp. was carried out using a minimum inhibitory concentration (MIC) assay on Muller Hinton Agar (MHA) medium using an E-test kit. The molecular detection of VRE isolates was performed by the PCR method using the vanA and vanB resistance genes. RESULTS: A total of 234 and 186 non-duplicate rectal swab samples were collected from patients at ICU admission and at discharge from ICU, respectively. Enterococcus spp. was detected in 34.6% (n = 81/234) of rectal swab samples collected from patients at ICU admission, of which 44.4% (n = 36/81) were VRE isolates. In contrast, the prevalence of Enterococcus spp. and VRE isolates among patients at discharge from ICU was 17.7% (n = 33/186) and 57.6% (n = 19/33), respectively. Out of 19 VRE isolated from patients at ICU admission, 4 (21%) and 1 (5.3%) contained vanA and vanB genes, respectively. In contrast, out of 36 VRE isolated from patients at discharge from ICU, 11 (30.5%) were positive for the vanA gene. CONCLUSION: Results revealed that the prevalence of Enterococcus spp. among patients at ICU admission was high. However, VRE was frequently isolated from patients who were hospitalized for several days in ICUs. The implementation of proper infection control strategies and the use of suitable protocols to guide the appropriate prescribing of antibiotics are necessary.