Common Microorganisms Research Articles

In vitro comparison of Enterococcus Faecalis survival in dentinal tubules following root canal therapy with AH plus, endoseal MTA, and cold ceramic sealers

BackgroundEnterococcus faecalis (E. faecalis) is the most common microorganism responsible for post-endodontic infections, which can penetrate deep into dentinal tubules. This study aimed to compare the survival of E. faecalis in dentinal tubules following root canal therapy with AH Plus (AHP), Endoseal MTA (ESM), and cold ceramic (CC) sealers.MethodsIn this in vitro experimental study, 80 single-canal human teeth were decoronated at the cementoenamel junction. The root canals were cleaned and shaped, and auto-clave sterilized after smear layer removal. The roots were then inoculated with E. faecalis, and incubated for 3 weeks. The teeth were randomly assigned to four groups (n = 20) for root canal obturation with AHP, ESM, and CC sealers and 2% gutta-percha with the cold lateral compaction technique. The fourth group served as the control group. After 30 days, dentin chips were collected from the canals, and cultured on blood agar. The colony count was reported and analyzed by the Kruskal-Wallis test (alpha = 0.05).ResultsThe mean colony count was 23.73 ± 13.84 in the AHP, 34.78 ± 18.75 in the ESM, and 28.47 ± 13.73 in the CC group after 30 days. The difference in this regard was not significant among the three experimental groups (P = 0.102).ConclusionsWithin the limitations of this in vitro study, the results indicated comparable antibacterial activity of AHP, ESM, and CC sealers against E. faecalis in infected dentinal tubules after 30 days.

Evaluation of C-Reactive Protein and Procalcitonin as a Mortality Indicator in Febrile Neutropenic Patients

Introduction: Febrile neutropenia (FN) develops as a side effect of chemotherapeutics in cancer patients. It causes complications, increased cost, and mortality. Microbiological agents can be detected in 30-50% of FN. Therefore, specific, highly effective, and rapid markers that can indicate infection are needed. Various biomarkers are under investigation and are still in use today. In this study, it was aimed to evaluate their effectiveness in early detection of infection and mortality by comparing quantitative C-reactive protein (CRP) and procalcitonin values at the beginning of FN and during treatment. Methodology This research is a retrospective, case-control study. The study included 572 FN patients who were followed up in the Hematology Clinic, Bone Marrow Transplantation Unit and Medical Oncology Clinic between 3 September 2018 and 25 May 2022. 748 FN attacks developed in these patients. The hospital information management system was analysed, and the data of the patients were recorded in the pre-prepared form. Data were analysed using ‘The Package for Social Sciences 26.0’ statistical program. Results: 49.1% of FN cases were female and 50.9% male. Hematological malignancy was detected in 60.8% of the patients. Mortality developed in 118 (20.6%) patients. The rate of bacteremia in FN attacks was 36.5%. The most common causative microorganism was Escherichia coli. Pseudomonas aeruginosa and Acinetobacter baumannii were more common in patients with mortality. CRP and procalcitonin values in the first five days of treatment were higher in patients with bacteremia and mortality. Prolonged neutropenia and bloodstream infection were found to be risk factors for mortality. Conclusion: It has been observed that CRP and procalcitonin values can be used both prognostically and diagnostically. It was found that resistant Gram-negative bacteria growth was higher in blood cultures of patients with mortality. More studies are needed to develop new treatment algorithms.

Effects of ultrasonic-alkali integrated extraction combined with Mannesi reaction on the antimicrobial properties of rice straw lignin and enhancement strategies

Lignin is one of the most abundant and underused biopolymers in nature with limited antimicrobial activities. Herein, this work aimed to enhance the antimicrobial activity of lignin extracted from waste rice straw by ultrasonic-alkali integrated extraction (USP-AT) and modify the alkali lignin through Mannich reaction to improve its antimicrobial properties. The effects of ultrasonic pretreatment (USP) time on the chemical structure, morphology, antioxidant, and antibacterial activities of lignin were studied. The results demonstrated that the total phenolic content of USP-AT lignin was higher than that of lignin extracted by alkali treatment. Moreover, the antioxidant activity of USP-AT lignin was increased by 49.69 %–69.42 %. The antibacterial activity of USP-AT lignin against Escherichia coli and Staphylococcus aureus increased by more than 40 %. However, the antibacterial capacity of USP-AT lignin is far from meeting the requirements of antibacterial food packaging. The alkali lignin was modified by Mannich reaction in order to improve its antimicrobial properties against common spoilage microorganisms or pathogenic bacteria in food and packaging. The modified USP-AT lignin exhibit remarkable antimicrobial capacities to representative bacteria, molds, and yeasts. The antifungal capacity of modified USP-AT lignin against A. niger and P. citrinum were improved by more than 40 %.

Results of the experimental study of the antimicrobial activity of therapeutic waters from various wells managed by the federation of trade unions of Uzbekistan

Introduction. Currently, in addition to the traditional use of mineral waters (MW) for the treatment of gastrointestinal tract and renal diseases, they are also used to correct metabolic disorders, normalize lipid and carbohydrate metabolism. However, many of its properties remain poorly studied, and there is a very limited number of works in the scientific literature concerning the analysis of their antibacterial action. Aim. Study of sensitivity of common microorganisms to the action of some MW. Materials and methods. The following test samples from different wells (DW) served as materials for determining the antimicrobial activity of mineral waters: Sample 1. Sodium bicarbonate weakly alkaline mineral water from SW No. 7 (Chinobod Sanatorium, Tashkent); Sample 2. Radon mineral water mineral water from SW No. 2 (Abu Ali ibn Sino Sanatorium, Samarkand Region); Sample 3. Iodine-bromine mineral water from SW No. 4 (Chartak Sanatorium, Namangan Region); Sample 4. Sulfate-sulfur mineral water from SW No. 14 (Chimen Sanatorium, Fergana Region); Sample 5. Concentrated iodine-bromine brine from SCW No. 2 (Chartak Sanatorium, Namangan Region). Results and discussion. Sample No. 5 (concentrated brine) showed antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa, the diameter of the growth inhibition zone was 22 ± 0.26 and 18 ± 0.35 mm, respectively. Also, sample No. 4 (Sanatorium Chimen DW No = 14, sulfate-sulfur mineral water) showed antimicrobial activity against Staphylococcus aureus, the diameter of the growth inhibition zone was 16 ± 0.11 mm. The samples did not show antimicrobial activity against the other test cultures. The antimicrobial action of water samples was determined by the agar diffusion method against some types of opportunistic bacteria: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and the yeast fungus Candida albicans. All microorganism cultures were obtained from the collection of the Institute of Microbiology of the Academy of Sciences of the Republic of Uzbekistan. The determination was achieved through the use of the agar diffusion method on a dense nutrient medium. Conclusion. It was found that sample No. 5 concentrated brine «Iodine-shifo» from the Chartak Sanatorium showed antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa, i. e. Staphylococcus aureus and Pseudomonas aeruginosa, the diameter of the growth inhibition zone was 22 ± 0.26 and 18 ± 0.35 mm, respectively. Also, sample No. 4 sulfate-sulfur mineral water from the Chimen Sanatorium showed antimicrobial activity against Staphylococcus aureus, the diameter of the growth inhibition zone was 16 ± 0.11 mm. The samples did not show antimicrobial activity against the other test cultures.

Characterization of sacha inchi (Plukenetia volubilis) and taro (Colocasia esculenta) flours with potential application in the preparation of both gluten-free and high protein foods.

Background Interest in alternative sources of tubers and legumes has increased in recent years because of the constant search for raw materials that provide bioactive compounds with antioxidant potential benefits for consumers. The functionality of new raw materials is sought through physical and/or chemical modifications to develop and innovate new foods. The objective of this study was to characterize taro (TF) (Colocasia esculenta) and sacha inchi (Plukenetia volubilis) flours, obtained by the wet (SIF-WM) and defatted method (SIF-DM), as an alternative for the formulation of new functional foods. Methods The free polyphenols of the different mixtures were analyzed, and the antioxidant properties of the extracts obtained were measured using ABTS.* (2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid). The ABTS radical method, which reacts with the phenolic compounds of the food matrix, using Trolox as a standard. The blends were subjected to pasting analysis, flow profile tests, determination of viscoelastic properties (temperature sweep). Characterization of common microorganisms in these foods was performed. Results The highest protein value was obtained in the sacha inchi flour obtained by the defatted method (72.62%). The majority of components in taro were carbohydrates (85.4%). About antioxidant and determination of free polyphenols, taro flour obtained values of 2.71 μmol ET/g and 7.47 mg EAG/g, higher than sacha inchi flours. In the rheological analysis (pasting properties, flow profile, and viscoelasticity), we observed that adding taro flour in different mixtures increases the viscosity peak and a lower breakdown, while there was an increase in setback. Except for defatted sacha flour, the others presented a flow index >1 before heating, showing a dilatant fluid behavior. The presence of taro flour improves gel formation and stability. Staphylococcus aureus and Salmonella were present in the taro flour. Conclusions The flours analyzed represent a raw material with great potential for the development of products such as protein snacks due to the contribution of sacha inchi, with good expansion due to taro starch, and naturally gluten-free for people with celiac disease.

Perithonsillar and parapharyngeal abscess: microbiological and morphological features

Introduction. The most dangerous local complication of acute and exacerbations of chronic inflammatory diseases of the pharynx is the formation of abscesses in the structure of the cellular spaces of the neck. Paratonsillar abscess (PTA) is the most common abscessing lesion. In turn, parapharyngeal abscess (PFA) is often found in patients with PTA as its complication.Aim. To study the clinical, microbiological and pathomorphological features of parapharyngeal complications in patients with PTA.Materials and methods. The analysis of medical records of 50 patients with diagnoses of parathonsillar and parapharyngeal abscesses who underwent inpatient treatment at the otorhinolaryngological department of the N.I. Pirogov State Clinical Hospital No. 1 in the period from September 2021 to April 2023 was carried out. The studied patients were divided into 2 groups. In group 2 of patients (n = 25; F 10, M 15; average age -37.2 years ± 10.8 years) an isolated PTA was diagnosed. In the 2 group of patients (n = 25; F 10, M 15, the average age was 44.6 years ± 14.8 years) PTA was complicated by the development of PFA.Results and discussion. Associations of facultative anaerobic and obligate anaerobic microorganisms were found in all pus aspirates obtained from PTA and PFA. Monocultures of microorganisms were not isolated in any case. The detection of Fusobacterium necrophorum was associated with pronounced necrotic changes in the tissues of the tonsils and surrounding structures; Peptostreptococcus anaerobius with purulent melting of fiber tissue; Veillonella dispar with pronounced infiltrative processes in tissues combined with oral pathology in patients.Conclusions. The most common microorganisms in patients with PTA and PFA were Streptococcus pyogenes and Fusobacterium necrophorum. The activity of Fusobacterium necrophorum is associated with a more severe course of the inflammatory process in the near-pharyngeal space.

Dietary bile acids supplementation protects against Salmonella Typhimurium infection via improving intestinal mucosal barrier and gut microbiota composition in broilers

BackgroundSalmonella Typhimurium (S. Typhimurium) is a common pathogenic microorganism and poses a threat to the efficiency of poultry farms. As signaling molecules regulating the interaction between the host and gut microbiota, bile acids (BAs) play a protective role in maintaining gut homeostasis. However, the antibacterial effect of BAs on Salmonella infection in broilers has remained unexplored. Therefore, the aim of this study was to investigate the potential role of feeding BAs in protecting against S. Typhimurium infection in broilers.MethodsA total of 144 1-day-old Arbor Acres male broilers were randomly assigned to 4 groups, including non-challenged birds fed a basal diet (CON), S. Typhimurium-challenged birds (ST), S. Typhimurium-challenged birds treated with 0.15 g/kg antibiotic after infection (ST-ANT), and S. Typhimurium-challenged birds fed a basal diet supplemented with 350 mg/kg of BAs (ST-BA).ResultsBAs supplementation ameliorated weight loss induced by S. Typhimurium infection and reduced the colonization of Salmonella in the liver and small intestine in broilers (P < 0.05). Compared to the ST group, broilers in ST-BA group had a higher ileal mucosal thickness and villus height, and BAs also ameliorated the increase of diamine oxidase (DAO) level in serum (P < 0.05). It was observed that the mucus layer thickness and the number of villous and cryptic goblet cells (GCs) were increased in the ST-BA group, consistent with the upregulation of MUC2 gene expression in the ileal mucosa (P < 0.05). Moreover, the mRNA expressions of Toll-like receptor 5 (TLR5), Toll-like receptor 4 (TLR4), and interleukin 1 beta (IL1b) were downregulated in the ileum by BAs treatment (P < 0.05). 16S rDNA sequencing analysis revealed that, compared to ST group, BAs ameliorated the decreases in Bacteroidota, Bacteroidaceae and Bacteroides abundances, which were negatively correlated with serum DAO activity, and the increases in Campylobacterota, Campylobacteraceae and Campylobacter abundances, which were negatively correlated with body weight but positively correlated with serum D-lactic acid (D-LA) levels (P < 0.05).ConclusionsDietary BAs supplementation strengthens the intestinal mucosal barrier and reverses dysbiosis of gut microbiota, which eventually relieves the damage to the intestinal barrier and weight loss induced by S. Typhimurium infection in broilers.

Microbiology testing capacity and antimicrobial drug resistance in surgical-site infections: a post-hoc, prospective, secondary analysis of the FALCON randomised trial in seven low-income and middle-income countries

Surgical-site infection (SSI) is one of the most common health-care-associated infections, substantially contributing to antibiotic use. Targeted antibiotic prophylaxis to prevent SSIs and effective treatment are crucial to controlling antimicrobial resistance (AMR). This study aimed to describe the testing capacity and multidrug resistance (MDR) of SSI microorganisms in low-income and middle-income countries (LMICs). This analysis included patients undergoing abdominal surgery in seven LMICs (Benin, Ghana, India, Mexico, Nigeria, Rwanda, and South Africa) as part of the FALCON randomised controlled trial. Wound swabs were collected from patients diagnosed with SSI, as per US Centers for Disease Control and Prevention (CDC) definition. Data on microorganism species and MDR, as per CDC and European Centre for Disease Prevention and Control definitions, were analysed alongside hospital-level data on local microbiological practices. An adjusted analysis was performed to identify perioperative factors associated with MDR. Testing capacity was assessed by the completion of swab testing in positively diagnosed SSIs. Between Dec 10, 2018, and Sept 7, 2020, 5788 patients were recruited to the FALCON trial. 1163 patients were diagnosed with an SSI, of whom 905 (77·8%) received prophylactic antibiotics before surgery. In patients with SSIs, 935 of 1163 (80·4%) did not have a wound swab; 195 were from hospitals not performing swabs (15 hospitals) and 740 were from hospitals with capacity but no swab performed (35 hospitals). Of 228 patients swabbed, 200 (88·5%) had microorganisms detected. Escherichia coli (89 of 200, 37·9%) was the most common microorganism and 116 of 200 (58·0%) patients were not covered by the perioperative prophylactic antibiotic. MDR was found in 102 of 147 (69·4%) patients for whom data were available to determine MDR status. Adjusted analysis found that appropriate prophylactic antibiotic coverage (adjusted odds ratio 0·43, 95% CI 0·19-0·96) and regular availability of infection control teams (0·32, 0·11-0·93) were associated with a significant reduction in MDR. Targeted perioperative antibiotic prophylaxis during contaminated abdominal surgery is insufficient in LMICs, with very few SSI organisms undergoing formal diagnosis. Expansion of testing capacity, development of local guidelines, and implementation of infection control teams could support the prevention of SSI through directed antibiotic prophylaxis, subsequently reducing the burden of MDR. National Institute for Health and Care Research. For the French and Spanish translations of the abstract see Supplementary Materials section.

The Extra Length of Stay, Costs, and Mortality Associated With Healthcare-Associated Infections: A Case-Control Study.

This study aims to compare the mortality rate, length of stay (LOS), and hospitalization cost in patients with and without healthcare-associated infections (HCAIs). This prospective cohort study is conducted on 396 matched patients admitted to a tertiary teaching hospital with 800 beds in the southwest of Iran from July 2021 to January 2022. The cases were patients admitted during the study period who had, at minimum, one type of HCAI. For a comparison group, we considered all patients without HCAIs who hospitalized in the same ward and at the same time with the same age and gender in a ratio of one case to three controls. Descriptive analyses were done based on direct medical costs, LOS, and mortality rate in patients. The magnitude of the relationship between potential risk factors and HCAI was quantified using logistic regression. The most common HCAI and microorganisms were urinary tract infection (UTI) and Escherichia coli, respectively. The mean LOS for infected patients was 20.3 (±16) days, compared to 8.7 (±8.6) days for noninfected patients (p value ≤ 0.05). Lengths of stay (odds ratio [OR] = 1.09; 95% CI = 1.06-1.19; p value = 0.000), ICU lengths of stay (OR = 1.08; 95% CI = 1.02-1.15; p value = 0.003), presence of central Catheter (OR = 0.127; 95% CI = 0.51-0.319; p value = 0.000), and urinary catheter (OR = 0.225; 95% CI = 0.122-0.415; p value = 0.000), mechanical ventilation (OR = 0.136; 95% CI = 0.57-0.325; p value = 0.000), receipt of immunosuppressors (OR = 1.99; 95% CI = 11.12-3.56; p value = 0.01), were Significantly associated with HCAI. Patients with infections had a more costly hospital stay than noninfected patients (mean diff: $2037.46 ([SD]: 482.25$) (p value = 0.000). The highest cost component was the cost of medication expenditure (mean: $1612.66 ([SD]: $2542.27). UTI was the most common HCAI in our study. An infection acquired during a hospital stay may be associated with higher hospitalization costs, prolonged hospitalization, and an increase in the rate of mortality. Longer lengths of stay, presence of central and urinary Catheters, receipt of immunosuppressors, use of mechanical ventilator were common risk factors for HCAI. This study reveals that the median reimbursement cost per hospitalization of patients with HCAIs was higher than patients without HCAIs. This highlights the necessity for implementation of HCAI prevention and control measures.

Features of the oropharyngeal microbiota of healthy children and those with acute respiratory infections. A prospective single-center randomized study

Background. The oropharyngeal microbiota is involved in the development of colonization resistance, affecting viral adhesion and metabolism. Any deviations in the stability of the environmental microbial niches of the oropharynx alter the local immune response and can trigger severe chronic somatic disorders. Aim. To compare the composition of the microbiota of children during an episode of respiratory infection and healthy volunteers examined in different periods of convalescence. The obtained data can be used to predict the course of the disease, analyze the risk of complications, and assess the frequency of the diseases in the future. Materials and methods. From 20.01.2022 to 23.12.2022, an open-label prospective single-center randomized comparative study was conducted, which included 120 children aged 5-10 who presented with symptoms of acute respiratory infection. The control group consisted of 15 asymptomatic children examined at different periods of convalescence. The study compared changes in the oral microbiota composition of patients and healthy children. The evaluation was performed using complete 16S rRNA gene sequencing on the Oxford Nanopore platform. Taxonometric analysis at the species and genera level was performed using the Knomics-Biota platform. The R programming language was used for statistical processing. In addition, the parameters of α- and β-diversity of the microbiota were assessed. The Chao1 and Shannon indices were calculated to assess α-diversity (diversity within one community). The Chao1 index is based on the number of species found in the sample and also rare species that are found only 1 or 2 times, thus preventing underestimation of diversity. The Shannon index includes both the number of species and their uniformity in the community. A change in the index indicates the dominance of one or more species. The following indicators were used to assess the β-diversity describing the differences between two microbiota samples at the species and genera level: Bray–Curtis dissimilarity (characterizing the ratios of common and different microorganisms between the samples) and the Aitchison distance (reflecting the differences in the proportions of microorganisms). In addition, the balance between the two groups of microorganisms was evaluated using the NearesBalance method, which characterizes the differences between the microbiota of the main and control groups. Results. The results of our study show that during respiratory infection, the state of the oropharyngeal microbiota is characterized by an increase in α-diversity, which is associated with an increase in the proportion of species of Streptococcus salivarius, Streptococcus pneumoniae, Streptococcus pseudopneumoniae, Streptococcus pyogenes, Streptococcus thermophilus and A12 versus the proportion of Streptococcus mitis, Streptococcus oralis, Streptococcus gwangjuense, Streptococcus sanguinis, Streptococcus gordonii and FDAARGOS_192. In the control group, the oropharyngeal microbiota was divided into two clusters. The dominance of streptococci was observed in the first group (control), while the second group had a more uniform representation. Analysis of the changes in microbial communities in the main and control groups can show the stages of oral microbiota recovery after an acute respiratory infection episode. Conclusion. More research is needed in the field of the oropharyngeal microbiome on a larger sample of healthy children, to standardize the communities of the oropharyngeal microbiota, to study the interaction within communities and with the body as a whole. Analysis of the impact of the microbiota on the frequency and course of respiratory infections and the rate of complications opens up new prospects in treating, rehabilitating, and preventing diseases. These research areas can contribute to improving children's health and quality of life and introducing new approaches into clinical practice.

The Impact of Beneficial Microorganisms on Soil Vitality: A Review

The paper summarizes the literature on the critical impact of beneficial microorganisms on soil vitality. Common soil microorganisms, including bacteria, fungi, algae, protozoa, and viruses contribute significantly to enhancing soil fertility through processes such as nitrogen fixation, phosphorus solubilization and mobilization, sulfur cycle, composting, and heavy metal remediation. Their abundance and biomass vary significantly across taxa within the uppermost 15 cm of soil, with bacteria dominating numerically and fungi contributing substantially to biomass. These microorganisms mediate essential biogeochemical cycles in soil, including carbon, nitrogen, and phosphorus cycles, by facilitating the decomposition of organic matter and recycling soil nutrients. Nitrogen-fixing bacteria like Rhizobium are prevalent symbionts capable of biologically fixing nitrogen. Additionally, bacteria such as Micrococcus spp., Enterobacter aerogens, Pseudomonas capacia, fungi including Aspergillus niger, A. flavus, A. japonicas, Penicillum spp., and actinomycetes like Streptomyces play crucial roles in phosphorus solubilization, making phosphorus available for plant uptake. This synthesis underscores the critical role of beneficial microorganisms in maintaining soil vitality. These organisms interact with plants through beneficial relationships, influencing soil fertility dynamics by enhancing nutrient availability, promoting plant growth, and controlling pathogens. The use of biofertilizers has emerged as a sustainable strategy to improve crop yields and restore soil fertility, reducing environmental impacts linked to chemical fertilizers. Understanding the intricate dynamics of soil-beneficial microorganism and their interactions with Plants are pivotal for optimizing agricultural practices, ensuring long-term soil health, and enhancing productivity in sustainable farming systems.

Surgical site infection and antimicrobial use following caesarean section at QECH in Blantyre, Malawi: a prospective cohort study

BackgroundSurgical site infections (SSIs) are one of the most common healthcare-associated infections and preventable complication of surgical procedure; continue to threaten public health with significant effects on the patients and health care human and financial resources. Therefore, this study aimed to determine the incidence of SSIs, risk factors and common microorganisms associated with SSI and assess the practice of antimicrobial use in women following Caesarean Section (CS) at Queen Elizabeth Central Hospital (QECH).MethodsThis was a hospital-based quantitative prospective study design involving pregnant women who underwent a CS between February, 2023 and July, 2023 at QECH with 30 day-follow-ups. Wound specimens (wound swabs) were collected from all infected CS wounds and processed at QECH main laboratory, and susceptibility testing was conducted using the Kirby-Bauer disk diffusion method with results reported only as susceptible, intermediate, or resistant and the collected data was analyzed using Stata.ResultsThe overall cumulative incidence of SSI recorded at QECH during the study period was 9.61% (20 cases out of 208). Of these, 19 (95%) of them reported superficial SSI following CS. The mean age was 26.1 years with a standard deviation of 6.2. All pregnant women who underwent for CS received antibiotic prophylaxis. This study revealed that 138 (66.35%) patients received both preoperative antibiotics (ceftriaxone) and post-CS antibiotics without knowing the specific bacterial organism isolated. This study revealed that ruptured membrane had twice the incidence of SSIs compared to intact membrane (χ2 = 2.0922), though not statistically significant. The majority of patients with SSIs (n = 12, 60%) were readmitted and 5 (25%) out of 20 with SSIs had antimicrobial resistance following susceptibility testing. Staphylococcus aureus was the most common organism (3, 60%) and other bacterial isolates included were Enterobacteriaceae and Acinetobacter baumanni.ConclusionThe incidence of SSIs and inappropriate antimicrobial use following CS remains a challenge at QECH. Therefore, due to increased number of SSIs following CS with relative emergence of AMR ensure intensive infection prevention and control practices, establishing AMS program and routine surveillance of SSIs at QECH.

Epidemiology and temporal trends of infective endocarditis between 2006 and 2018 at a tertiary referral center

Abstract Introduction Despite modern diagnostics, targeted antibiotic therapy and surgical treatment the mortality rate of infective endocarditis (IE) remains high. In developed countries both the risk factors and pathogens have changed. Objective and methods In our retrospective study we analyzed the clinical and microbiological characteristics, short- and long-term all-cause mortality, and temporal trends of consecutive patients admitted with IE between 2006 and 2018. Results We included 537 cases in our study, the mean age was 55.9 ± 16.5 years (72.2% male). 325 (60.5%) cases were native left-sided IE, 14 (3%) cases were right-sided IE, 130 (24%) cases were prosthetic valve IE, 62 (11.5%) cases were intracardiac device-related IE and 6 (1%) other cases. The most common microorganisms were Staphylococci (n=175; 33%), including 104 cases of methicillin-sensitive Staphylococcus aureus (MSSA), 27 cases of methicillin-resistant Staphylococcus aureus (MRSA) and 44 cases of coagulase-negative Staphylococci. Streptococcus species were identified in 141 cases (26%), Enterococcus species in 88 cases (16%) and 72 cases (13%) were classified as blood culture-negative IE. In-hospital all-cause mortality was 14%, mortality at six months was 27%, at one-year was 31%, and at five-year was 45%. The incidence of MSSA infections increased over time (p=0.024), while coagulase-negative Staphylococci (p&amp;lt;0.001), and Streptococci (p=0.047) infections decreased. None of the observed mortality rates showed significant change over the study period. Predictors of mortality were advanced age (HR 1.37; p&amp;lt;0.001), impaired renal function (HR: 1.03; p&amp;lt;0.001), reduced ejection fraction on admission (HR 1.38; p&amp;lt;0.001), stroke (HR 1.74; p=0.001), and MRSA infection compared to Streptococci (HR 2.56; p=0.002). Conclusion During the observed 13-year period Staphylococci were the most common pathogens, with an increasing incidence of MSSA infection in our tertiary center. The mortality rate of IE remained high and showed no improvement over time.

Relapse of infective endocarditis after cardiac implantable electronic device removal compared to a conservative strategy

Abstract Background According to current guidelines, complete removal of cardiac implantable electronic device (CIED) should be considered in patients with valvular infective endocarditis (IE), accounting for the identified pathogen and need for valve surgery (Class IIa recommendation). Unselected longitudinal data are needed to assess this strategy. Purpose To examine IE readmission after IE discharge according to status of CIED removal in patients with conservatively treated IE. Methods Using Danish nationwide registries, we identified patients aged ≥18 years with first-time IE from 2010-2021. We included patients with conservatively treated IE and a CIED, who were alive at IE discharge. Patients who underwent CIED removal during IE admission were compared to those without removal, examining the study outcome of IE readmission within six months after IE discharge. An initial blanking period of 14 days was applied after IE discharge. The Aalen-Johanson estimator and multivariable Cox regression models were used to determine cumulative incidences and adjusted hazard ratios (HRs) of IE readmission according to status of CIED removal, respectively. Results Among 6,843 patients with first-time IE, 5,731 (83.7%) were conservatively treated. Of these, 1,201 (21.0%) had a CIED, of which 205 (17.1%) died during IE admission. Thus, the final study population comprised 996 patients alive at IE discharge. The median age of the study population was 75.5 years (interquartile range [IQR]: 67.9-82.0), and 753 (75.6%) were males. In total, 574 (57.6%) patients underwent CIED removal during IE admission. Patients who underwent CIED removal were younger, compared to patients without CIED removal, 73.1 years (IQR: 65.7-79.1) versus 79.0 years (IQR: 71.3-85.1), respectively. The six-month cumulative incidence of IE readmission was 2.0% (95% confidence interval [CI]: 1.1-3.5%) in patients who underwent CIED removal versus 6.1% (95% CI: 4.0-8.9%) in patients without CIED removal (P-value=0.001) (Figure 1). CIED removal was associated with a significantly lower six-month rate of IE readmission, compared to no CIED removal (HR: 0.36 [95% CI: 0.17-0.77]). Relapse bacteraemia (including IE) with the same microorganism as first-time IE occurred in 2.2% of patients who underwent CIED removal and in 5.4% of patients without CIED removal. Staphylococcus aureus was the most common microorganism in 33.3% of patients with relapse bacteraemia who underwent CIED removal. Conclusions In this nationwide study, the six-month rate of infective endocarditis (IE) readmission was three-fold lower in patients who underwent cardiac implantable electronic device (CIED) removal, compared to patients without CIED removal. The current findings suggest that CIED removal is associated with lower risk of relapse of IE in patients with conservatively treated IE. These results are in line with current guideline recommendations. However, more randomized clinical trial data are needed.

Epidemiological profile and mortality of infective endocarditis over the past decade: a systematic review and meta-analysis of 133 studies comprising 132,355 cases

Abstract Background Understanding the epidemiology of infective endocarditis (IE) is crucial in the context of an aging population, increased comorbidities, and the heightened occurrence of healthcare-associated cases. Comprehensive data on causative agents, affected valves, and associated mortality are essential for current clinical practice. Methods This systematic review was conducted according to the PRISMA guidelines. A random effects model meta-analysis was conducted. Eligible studies reporting outcomes on IE were identified through a search of the PubMed/Medline database from 2010 to 2021. Results One hundred-thirty-three studies with 132,584 patients from six continents were included in the analysis. The most common causative agents of IE were Staphylococci species in 36% of cases, followed by Streptococci species in 26% of cases and Enterococci species in 10% of cases. Of the studies providing further speciation, the predominant species was Staphylococcus aureus with an incidence of 29%, followed by Viridans Streptococcus with an incidence of 12%. We found an in-hospital/30-day mortality of 17% (CI: 16%-19%) from 109 studies worldwide. In the subgroup analysis, the highest mortality rates were observed in Latin America 33% (CI: 28%-38%) and Africa 25% (CI: 21%-30%), while the lowest mortality rates were reported in Oceania 13% (CI: 8%-19%), followed by North America 14% (CI: 11%-18%), Asia 15% (CI: 12%-18%), and Europe 17% (CI: 16%-19%). The aortic valve was affected in 46% of cases, followed by the mitral valve in 43%. Tricuspid valve IE and multivalvular IE were identified in 7% and 14% of the cases, respectively. Conclusion Our study highlights the shift in epidemiological profile of IE over the last decade with S. aureus identified as the most common causative microorganism of IE in almost one third of cases. IE remains a highly morbid and fatal condition with high mortality rates even in tertiary and high-expertise centers worldwide. While left-sided IE is by far more common, right-sided IE and multivalvular IE are not rare entities and should be considered early in the differential of patients presenting with suspected IE to decrease the risk of future complications.Global burden of infective endocarditis.

Epidural Catheter Bacterial Colonization and Infection in a Secondary Portuguese Hospital Setting.

Background and study goal Epidural analgesia is effective for postoperative pain control but carries risks of infection, including bacterial colonization. This study aimed to determine the incidence of epidural catheter colonization and infection in a Portuguese hospital, identify common microorganisms and antibiotic resistance profiles, and assess potential risk factors. Materials and methods We conducted a prospective observational study from November 2022 to March 2023 in a Portuguese secondary care center. Adult patients undergoing surgery with epidural analgesia were included. Data related to patient demographics, surgical details, and the epidural technique were collected. Incidence rates were calculated, and risk factors for colonization were analyzed. Results and discussion Overall, 215 patients were included (mean age: 52.12 years; 76.7% women). The average catheter duration was 2.66 days. The incidence of bacterial colonization was 16.3% (95% CI=11.3-21.2%), with 74.3% showing antibiotic resistance. Staphylococcus epidermidis was the most frequent isolate (37.1%). No cases of epidural space infection were observed. Exploratory analyses indicated a potential higher risk of colonization when multiple punctures were needed (adjusted odds ratio (aOR): 4.52, p=0.33). Conclusion Epidural catheter colonization occurred in 16.3% of cases, with Staphylococcus epidermidis being the predominant agent. Despite colonization, clinical infections were rare. The high rate of antibiotic resistance underscores the need for improved stewardship and aseptic practices.

Risk factors for bacterial stent colonization in patients with a double J ureteral stent: a prospective study.

The increasing use of double J ureteral stents (DJS) has increased the risk of early intolerance and long-term complications. Studies have reported stent colonization rates ranging from 19 to 90% with various bacterial profiles in the colonization of stents. To identify the risk factors associated with bacterial colonization of DJS and report the common micro-organisms isolated and drug susceptibility pattern. This study is a prospective study of patients who underwent DJS. A total of 48 patients from our institution were studied between March 2022 and August 2023. After the removal of DJS with a sterile technique, the tips of both ends (renal end and bladder end) of the stent were cut and processed in the microbiology lab. Bacterial colonies were detected in 56.25% (27 out of 48) of the stents. Among the pathogens identified, Enterococcus species, Pseudomonas aeruginosa and E. coli were the most frequently isolated. The colonization rate increased with the duration of stent placement and albuminuria. The study indicated that prolonged indwelling time and albuminuria are a risk factor for bacterial colonization on the stent therefore, it is advisable to use double J ureteral stent only when absolutely necessary and to remove them promptly.

Preinoculation with Bradyrhizobium japonicum enhances the salt tolerance of Glycine max seedlings by regulating polyamine metabolism in roots

Rhizobia are common symbiotic microorganisms in the root system of leguminous plants that can usually provide nitrogen to the host through nitrogen fixation. Studies have shown that rhizobium-preinoculated soybean plants usually exhibit improved salt tolerance, but the underlying mechanism is not fully understood. In this paper, transcriptome sequencing (RNA-seq) revealed that preinoculation with rhizobia affected polyamine (PA) metabolism in soybean roots. The assay of PA contents showed that preinoculation with rhizobia significantly increased the putrescine (Put) content in roots and leaves during short-term salt treatment (0–5 d). Long-term salt treatment (5–7 d) resulted in a high Put content and significantly increased Spm and Spd contents, resulting in a rapid increase in the Put/(Spd + Spm) ratio (0–5 d) and subsequent decrease. Moreover, rhizobium preinoculation of soybean plants resulted in increased contents of conjugated and bound PAs under salt stress. Further transcriptome sequencing, PA contents, PA synthase expression and activity analysis revealed that GmADC may be a key gene related to salt tolerance in rhizobium-preinoculated soybean plants, and the GmADC-overexpressing soybean hairy-root composite plants exhibited less ROS damage, lower Cl−/NO3− ratios and Na+/K+ ratios, and stabilized ion homeostasis. Taken together, preinoculation with rhizobia increased the expression level and enzyme activity of arginine decarboxylase (ADC) in soybean roots, increased the content of Put in roots and leaves, and increased the content of conjugated and bound PAs in soybean plants, thereby alleviating the oxidative and ionic injuries of soybean plants and enhancing the salt tolerance.

Bloodstream infections in a Brazilian Pediatric Tertiary Oncology Hospital: 30-month analysis regarding the classification of the infection, distribution of microorganisms and their resistance profile

Abstract Background Infections are a major cause of morbidity and mortality in pediatric oncology patients during their treatment. Bloodstream infections are the main site of infection in these patients. Bacteremia in these patients can be secondary to a primary infectious focus, result from central line associated bloodstream infections (CLABSIs) or mucosal barrier injury laboratory-confirmed bloodstream infection (MBI-LCBI). Methods Descriptive study of bloodstream infections in pediatric patients undergoing oncological treatment and hematopoietic stem cell transplantation in a tertiary pediatric oncology hospital in Brazil from January 1st, 2021 to June 30th, 2023. Infections were classified according to the Centers for Disease Control and Prevention/ National Healthcare Safety Network (CDC/NHSN) criteria into CLABSIs, MBI-LCBIs and secondary bloodstream infections. Among the bloodstream infections that met CDC/NHSN criteria for CLABSI, were analyzed separately those who also met the criteria of catheter-related bloodstream infection (CRBSI) according to Infectious Diseases Society of America (IDSA). Results During this period were diagnosed 335 episodes of bloodstream infection (123 episodes in 2021, 150 in 2022 and 62 episodes in the first 6 months of 2023). There were 378 microorganisms isolated. These infections were classified into: 35% CLABSIs, 27% MBI-LCBIs, 23% CRBSIs, and 15% secondary bloodstream infections. Among the CLABSIs, the most common microorganisms were non-fermenting gram negative bacilli (NFGNB) 38%, enterobacteriaceae 35% and coagulase-negative staphylococcus (CoNS) 11%. Between CRBSIs, there were 31% enterobacteriaceae, 22% CoNS and 19% NFGNB. Among the MBI-LCBIs there were 66% enterobacteriaceae and 23% group viridans streptococci (VGS). Streptococcus pneumoniae (33%) was the most common microorganism in secondary infections followed by Staphylococcus aureus (17%). Assessing all infections together, the main enterobacteriaceae were Klebsiella spp. (40%) and only 50% of them were sensitive to cefepime while 10% were carbapenems resistant. Among NFGNB, 13% of Pseudomonas spp. and 5% of Acinetobacter spp. were carbapenems resistant. Between the gram-positive bacteria, 77% of the S. aureus were methicillin sensitive, the same percentage of the VGS were sensitive to cefepime. Conclusion Among bloodstream infections, there were a predominance of CLABSI followed by MBI-LCBIs. Antimicrobial resistance between gram-positive bacteria, is of little concern in our institution. In the case of gram-negative bacteria, resistance to cefepime is becoming worrying among enterobacteriaceae.

The utilization of N-acetylgalactosamine and its effect on the metabolism of amino acids in Erysipelotrichaceae strain

BackgroundThe metabolism of gut microbiota produces bioactive metabolites that modulate host physiology and promote self-growth. Erysipelotrichaceae is one of the most common anaerobic microorganism families in the gut, which has been discovered to play a vital role in host metabolic disorders and inflammatory diseases. Our previous study found that N-acetylgalactosamine (GalNAc) in caecal content of pigs significantly affected the abundance of Erysipelotrichaceae strains. However, it remains unknown how GalNAc feeding in vitro culture affects the expression levels of genes in the GalNAc metabolic pathway and the concentrations of intermediate metabolites in the Erysipelotrichaceae strain. Whether GalNAc feeding should influence the metabolism of other nutrients, such as amino acids, remains unrevealed.ResultsIn this study, whole-genome sequence, transcriptome, and metabolome data were analyzed to assess the utilization of a Erysipelotrichaceae strain on GalNAc. The results showed the presence of a complete GalNAc catabolism pathway in the genome of this Erysipelotrichaceae strain. GalNAc feeding to this Erysipelotrichaceae strain significantly changed the expression levels of genes involved in glycolysis and tricarboxylic acid (TCA) cycle. Meanwhile, the concentrations of lactate, pyruvate, citrate, succinate and malate from the glycolysis and TCA cycle were significantly increased. In addition, transcriptome analysis indicated that the genes involved in the metabolism of amino acids were affected by GalNAc, including lysA (a gene involved in lysine biosynthesis) that was significantly down-regulated. The intracellular concentrations of 14 amino acids in the Erysipelotrichaceae strain were significantly increased after feeding GalNAc.ConclusionsOur findings comfirmed and extended our previous works that demonstrated the utilization of GalNAc by Erysipelotrichaceae strain, and explained the possible mechanism of GalNAc affecting the abundance of Erysipelotrichaceae strain in vitro.