Risk factors for secondary infection after liver failure and effect of comprehensive nursing intervention.

BACKGROUND: In patients with liver failure (LF), the high rate of secondary infections, which are associated with poor prognosis, highlights the clinical significance of understanding the underlying risk factors and implementing targeted intervention programs. AIM: To investigate risk factors for secondary infections in patients with LF and evaluate the effectiveness of comprehensive nursing interventions. METHODS: This retrospective study included 64 patients with LF, including 32 with and 32 without secondary infections. A questionnaire was used to collect data on age; laboratory parameters, including total and direct bilirubin, prothrombin time, blood ammonia, and other biochemical parameters; invasive procedures; and complications. Patients with secondary infections received comprehensive nursing intervention in addition to routine nursing care, whereas those without secondary infections received only routine nursing care to compare the effect of nursing intervention on outcomes. RESULTS: The infection rate, which was not associated with age or complications, was significantly associated with biochemical parameters and invasive procedures (P < 0.05). The infection rate was 61.6% in patients who had undergone invasive procedures and 32.1% in those who had not undergone invasive procedures during the hospital stay. The infection rate was also significantly associated with the type of LF (P < 0.05), with the lowest rate observed in patients with acute LF and the highest rate observed in those with subacute LF. The nursing satisfaction rate was 58.3% in the uninfected group and 91.7% in the infected group, indicating significantly higher satisfaction in the infected group (P < 0.05). CONCLUSION: In patients with LF, the rate of secondary infections was high and associated with biochemical parameters and type of LF. Comprehensive nursing intervention can improve patient satisfaction.

Comparison of microbiological and molecular diagnosis for identification of respiratory secondary infections in COVID-19 patients and their antimicrobial resistance patterns.

We report the use of a new multiplex Real-Time PCR platform to simultaneously identify 24 pathogens and 3 antimicrobial-resistance genes directly from respiratory samples of COVID-19 patients. Results were compared to culture-based diagnosis. Secondary infections were detected in 60% of COVID-19 patients by molecular analysis and 73% by microbiological assays, with no significant differences in accuracy, indicating Gram-negative bacteria as the predominant species. Among fungal superinfections, Aspergillus spp. were detected by both methods in more than 7% of COVID-19 patients. Oxacillin-resistant S. aureus and carbapenem-resistant K. pneumoniae were highlighted by both methods. Secondary microbial infections in SARS-CoV-2 patients are associated with poor outcomes and an increased risk of death. Since PCR-based tests significantly reduce the turnaround time to 4 hours and 30 minutes (compared to 48 hours for microbial culture), we strongly support the routine use of molecular techniques, in conjunction with microbiological analysis, to identify co/secondary infections.

Risk factors for prolonged infection and secondary infection in pediatric severe sepsis.

PURPOSE: Sepsis causes significant worldwide morbidity and mortality. Inability to clear an infection and secondary infections are known complications in severe sepsis and likely result in worsened outcomes. We sought to characterize risk factors of these complications. METHODS: We performed a secondary analysis of clinical data from 401 subjects enrolled in the PHENOtyping sepsis-induced Multiple organ failure Study. We examined factors associated with prolonged infection, defined as infection that continued to be identified 7 days or more from initial identification, and secondary infection, defined as new infections identified ≥ 3 days from presentation. Multivariable adjustment was performed to examine laboratory markers of immune depression, with immunocompromised and immunocompetent subjects analyzed separately. RESULTS: Illness severity, immunocompromised status, invasive procedures, and site of infection were associated with secondary infection and/or prolonged infection. Persistent lymphopenia, defined as an absolute lymphocyte count (ALC) < 1000 cells/µL twice in the first five days, and persistent neutropenia, defined as absolute neutrophil count (ANC) < 1000 cells/µL twice in the first five days, were associated with secondary and prolonged infections. When adjusted in multivariable analysis, persistent lymphopenia remained associated with secondary infection in both immunocompromised (aOR = 14.19, 95% CI [2.69, 262.22] and immunocompetent subjects (aOR = 2.09, 95% CI [1.03, 4.17]). Persistent neutropenia was independently associated with secondary infection in immunocompromised subjects (aOR = 5.34, 95% CI [1.92, 15.84]). Secondary and prolonged infections were associated with worse outcomes, including death. CONCLUSIONS: Laboratory markers of immune suppression can be used to predict secondary infection. Lymphopenia is an independent risk factor in immunocompromised and immunocompetent patients for secondary infection.

Risk of severe dengue during secondary infection: A population-based cohort study in Taiwan.

BACKGROUND: Dengue poses a significant public health concern. Secondary dengue infections with different dengue virus (DENV) serotypes have been linked to an increased risk of severe dengue. This study aimed to assess the risk of severe dengue during secondary infection in Taiwan. METHODS: A retrospective cohort study was conducted using Taiwan's National Health Insurance Research Database to identify dengue cases with secondary dengue infection born after 1944 from 2014 to 2015. Ten matched patients with primary infection were selected as controls using propensity score matching for each secondary dengue infection case. The odds ratio (OR) for severe dengue in secondary versus primary infections was calculated using conditional logistic regression. RESULTS: This study included 357 cases with secondary dengue infection and 3570 matched controls. The risk of severe dengue was found to be 7.8% in individuals with secondary infection, compared to 3.8% in those with primary dengue infection. Secondary infection significantly increased the risk of severe dengue (OR 2.13, 95% CI: 1.40-3.25, P = 0.0004). Notably, a significant association between secondary infection and severe dengue was observed only when the interval between the first and secondary infection was greater than two years (OR 3.19, 95% CI 2.04-5.00, P < 0.0001). CONCLUSION: Secondary dengue infection significantly increases the risk of severe disease in Taiwan, particularly when the interval between infections is over two years. Healthcare professionals should maintain heightened vigilance for individuals with a history of previous dengue infection, particularly if their initial diagnosis was more than two years prior.

An Observational Study to Find the Association of Viral Load, NS1 Antigen, IgG Antibody, and Other Laboratory Parameters With the Outcome of Dengue Patients in Eastern India.

Background Dengue, the mosquito-borne febrile disease caused by the dengue virus, has become one of the major concerns of public health. It may present with only fever, or there may be a hemorrhagic manifestation or septic shock. As there is no specific treatment for dengue, early detection of the disease, assessment of progression, and prediction of outcome by studying the laboratory markers will help guide the management of cases and lower morbidity and mortality. Methodology This clinico-observational study was conducted at the Department of Microbiology in a tertiary care hospital in Kolkata, India, from February 2020 to August 2022 to determine the outcome of dengue patients in correlation with viral load, NS1 antigen, IgM and IgG antibodies, ferritin level, platelet count, and other laboratory parameters. Results Out of 316 samples from fever patients, 103 (32.5%) were NS1 antigen reactive. We followed up the dengue patients (n = 103) for 15 days and divided them into three groups according to their duration of symptoms (group A suffered for ≤5 days, group B for 5 to 10 days, and group C for >10 days) and per the WHO classification of disease severity, namely dengue without warning signs (DOS), dengue with warning signs (DWS), and severe dengue (SD). Based on severity, 65 (63.1%) patients had DOS, whereas 31 (30.09%) patients had DWS, and seven (6.79%) patients had SD. Secondary infection was present in 83.33% of patients in group C, 71% of DWS cases, and 57% of SD cases, which positively correlates with liver enzymes, viral load (mean value 102195 in secondary infection vs. 1195 copies/10 µl in primary infection), and negatively correlates with platelet counts (mean value 60,213 in secondary infection vs. 1,25,516 in primary infection). Patients in group C had higher liver enzymes, a lower platelet count, and a higher initial viral load than groups A and B. Similarly, SD cases had a higher ferritin level (9215 ug/l), a lower platelet count (mean value 23,250), and a higher initial viral load (mean value 2,74,257 copies/10 µl). An increase in hematocrit value considering the peak value and its baseline value is an important marker for disease severity rather than its absolute value. Conclusion Poor outcome of dengue infection, i.e., an increase in the duration of symptoms and disease severity depends on concurrent associations between high serum ferritin, increased hematocrit level, thrombocytopenia, secondary infection, increasing liver enzymes, and increased initial viral load.

Eczema herpeticum in an immunocompetent man.

BACKGROUND: Eczema herpeticum is a rapidly progressing skin complication related to the herpes simplex virus, particularly in individuals with compromised immune systems or atopic dermatitis. Eczema herpeticum is characterized by cutaneous pain, scaling, and the presence of vesicular lesions, often accompanied by secondary infection. Dissemination of the infection can lead to severe morbidity and mortality in patients without appropriate antiviral and antibiotic therapy. CASE REPORT: We presented a case of ankylosing spondylitis in a relatively young patient who did not receive immunosuppressive therapy and had no history of Human Immunodeficiency Virus, herpes zoster infection or atopic dermatitis. The patient's symptoms improved following a course of antiviral and antibiotic treatments. INTRODUCTION: The incidence of eczema herpeticum has been on the rise in recent decades, primarily due to an increased number of individuals with compromised immune systems. This increase can be attributed to various factors, including the higher prevalence of Human Immunodeficiency Virus/ Acquired Immunodeficiency Syndrome, the more extensive use of immunosuppressive therapy, and what seems to be a growing incidence of atopic dermatitis.[1] This disease can be initially mistaken for Stevens-Johnson syndrome because of the rapid advancement of skin lesions, however, the atypical target lesions, flaccid bullae and prominent mucosal involvement found in Stevens-Johnson syndrome are absent in cases of eczema herpeticum. Other differential diagnoses include impetigo, disseminated herpes zoster, acute generalized exanthematous pustulosis, dermatitis herpetiformis.

Disasters pile up on the rubbing heel: Sporothrix globosa as secondary infection to Mycobacterium chelonae infection.

Mycobacterium chelonae and Sporothrix globosa, both of which are opportunistic pathogens, have been proved to be possible multidrug resistant. However, are all recurring symptoms in chronic infections related to decreasing susceptibility? Here we report a case of sporotrichosis secondary to M. chelonae infection. In addition, we find that the blackish-red spots under the dermoscopic view can be employed as a signal for the early identification and regression of subcutaneous fungal infection.

The correlation between intestinal colonization and infection of carbapenem-resistant Klebsiella pneumoniae: A systematic review.

As a widely spread Gram-negative bacteria, Klebsiella pneumoniae (KP) mainly causes acquired infections in hospitals, such as lung infections, urinary tract infections, and bloodstream infections. In recent years, the number of multidrug-resistant KP strains has increased dramatically, posing a great threat to human health. Carbapenem-resistant KP (CRKP) can be colonized in human body, especially in gastrointestinal tract, and some colonized patients can be infected during hospitalization, among which invasive operation, underlying disease, admission to intensive care unit, antibiotic use, severity of the primary disease, advanced age, operation, coma, and renal failure are common risk factors for secondary infection. Active screening and preventive measures can effectively prevent the occurrence of CRKP infection. Based on the epidemiological status, this study aims to discuss the correlation between colonization and secondary infection induced by CRKP and risk factors for their happening and provide some reference for nosocomial infection prevention and control.

Bacterial and fungal secondary infections occurring in COVID-19 patients followed in intensive care: a retrospective study.

INTRODUCTION: We aimed to investigate the effects of secondary bacterial and fungal infections on patient outcomes in patients followed up in the intensive care unit (ICU) due to coronavirus disease 2019 (COVID-19). METHODOLOGY: We retrospectively analyzed reverse transcriptase polymerase chain reaction (RT-PCR) positive COVID-19 patients followed in the ICU of our hospital between March 2020 and June 2021, using the hospital information system. Demographic data, pathogens causing a secondary infection, onset time of secondary infection, and patient outcomes were recorded. RESULTS: A total of 251 RT-PCR positive patients who met the inclusion criteria were evaluated. The mean length of stay (LOS) in the ICU was 13.3 ± 9.6 days. During this period, 165 (65.7%) patients died. When blood, urine, respiratory tract, and catheter cultures were examined, the number of patients with growth in at least one culture was 129 (51.4%). There was growth in a total of 227 cultures. The highest culture positivity rate was observed in respiratory tract samples (n = 94, 41.4%). Gram-negative bacterial pathogens (n = 130, 58.4%) predominated. Candida spp. was more frequent in urine cultures. The median day of the occurrence of secondary infection was 10 (range: 6-15). Patients who developed secondary infection had a longer LOS and higher mortality rate than patients who did not (p < 0.001). CONCLUSIONS: Gram-negative secondary infections, predominantly in respiratory tract cultures, occurred in COVID-19 patients followed in the ICU. As a result, the LOS was prolonged and mortality rates increased.

Analysis of factors influencing the risk of secondary infection in patients colonized or infected with multidrug-resistant Gram-negative bacteria following hospitalization.

We seek to investigate the multifaceted factors influencing secondary infections in patients with multidrug-resistant Gram-negative bacteria (MDR-GNB) colonization or infection post-hospitalization. A total of 100 patients with MDR-GNB colonization or infection were retrospectively reviewed, encompassing those admitted to both the general ward and intensive care unit of our hospital from August 2021 to December 2022. Patients were categorized into the control group (non-nosocomial infection, n = 56) and the observation group (nosocomial infection, n = 44) based on the occurrence of nosocomial infection during hospitalization. Clinical data were compared between the two groups, including the distribution and antibiotic sensitivity of MDR-GNB before nosocomial infection. Significant differences were observed between the two groups in terms of age, underlying diseases, immune status, length of stay, and invasive medical procedures (P < 0.05). The observation group also had fewer patients practicing optimized hygiene, strict isolation, and antibiotic control than the control group (P < 0.05). Factors influencing the risk of secondary infection after hospitalization in patients colonized or infected with MDR-GNB included patient age, underlying diseases, immune status, length of hospitalization, medical invasive procedures, optimized hygiene, strict isolation, and antibiotic control (P < 0.05). The length of hospitalization and treatment cost in the observation group were higher than those in the control group (P < 0.05). This study comprehensively analyzes the intricate mechanisms of secondary infections in patients with MDR-GNB infections post-hospitalization. Key factors influencing infection risk include patient age, underlying diseases, immune status, length of hospitalization, medical invasive procedures, optimized hygiene, strict isolation, and antibiotic control.

Effect of combined infection with Salmonella and influenza virus on their respective proliferation in chicken embryonated eggs.

Background: Salmonella is a major food-borne bacterial pathogen that causes food poisoning related to the consumption of eggs, milk, and meat. Food safety in relation to Salmonella is particularly important for eggs because their shells as well as their contents can be a source of contamination. Chicken can also be infected with influenza virus, but it remains unclear how co-infection of Salmonella and influenza virus affect each other. Aim: The potential influence of co-infection of Salmonella and influenza virus was examined. Methods: Salmonella Abony and influenza virus were injected into chicken embryonated eggs. After incubation, proliferation of Salmonella and influenza virus was measured using a direct culture assay for bacteria and an enzyme-linked immunosorbent assay for influenza virus, respectively. Results: Our findings indicate that the number of colony-forming units (CFUs) of Salmonella did not vary between chicken embryonated eggs co-infected with influenza A virus and Salmonella-only infected eggs. Furthermore, we found the proliferation of influenza A or B virus was not significantly influenced by co-infection of the eggs with Salmonella. Conclusion: These results suggest that combined infection of Salmonella with influenza virus does not affect each other, at least in terms of their proliferation.

The role of long-lived plasma cells in viral clearance.

The adaptive immune system has two types of plasma cells (PC), long-lived plasma cells (LLPC) and short-lived plasma cells (SLPC), that differ in their lifespan. In this paper, we propose that LLPC is crucial to the clearance of viral particles in addition to reducing the viral basic reproduction number in secondary infections. We use a sequence of within-host mathematical models to show that, CD8 T cells, SLPC and memory B cells cannot achieve full viral clearance, and the viral load will reach a low positive equilibrium level because of a continuous replenishment of target cells. However, the presence of LLPC is crucial for viral clearance.

Secondary infections and long-term outcomes among hospitalized elderly and non-elderly patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and treated with baricitinib: a comparative study from the national centre of Hungary.

Baricitinib is considered a first-line treatment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected adult patients with an associated cytokine storm syndrome (CSS). Our objective was to compare rates of secondary infections and long-term outcomes of elderly and non-elderly patients who received baricitinib for COVID-19. We conducted a single-centre observational study between November 2020 and September 2023, focusing on hospitalized adult SARS-CoV-2 patients with CSS, categorized as elderly (≥ 65 years) and non-elderly (< 65 years). Enrolment, severity stratification, and diagnosis of infectious complications followed predefined criteria. Outcomes of all-cause mortality and rates of non-severe and severe secondary infections were assessed at 1-year post-treatment initiation. Kaplan-Meier analysis was performed for survival analysis. In total, 490 patients were enrolled (median age 65 ± 23 (21-100) years (years, median ± IQR, min-max); 49.18% elderly; 59.59% male). Elderly patients were admitted to the hospital significantly earlier (7 ± 5 days vs. 8 ± 4 days; p = 0.02), experienced a higher occurrence of severe COVID-19 (121/241, 50.21% vs. 98/249, 39.36%; p = 0.02), and required the use of non-invasive ventilation at baseline (167/225, 74.22% vs. 153/236, 64.83%; p = 0.03). At 1 year, all-cause mortality was significantly higher in the elderly subgroup (111/241, 46.06% vs. 29/249, 11.65%; p < 0.01). At 90 days and 1 year, rates of any severe secondary infection were also more prevalent among the elderly (56/241, 23.24% vs. 37/249 14.86%; p = 0.02 and 58/241, 24.07% vs. 39/249, 15.66%; p = 0.02). In conclusion, elderly SARS-CoV-2-infected patients experience a more severe clinical course, higher secondary infection rates, and increased risk for long-term mortality, regardless of immunomodulatory therapy.

Fetal Cytomegalovirus Infection in the Absence of Maternal Cytomegalovirus-IgM Seropositivity.

The aim of this study was to evaluate maternal serological status and fetal sonographic findings of Cytomegalovirus (CMV) infection. This is a retrospective study performed at Perinatology Department of Istanbul Basaksehir Çam and Sakura City Hospital. A computerized search was conducted to identify cases who underwent prenatal diagnosis of fetal CMV infection between September 2020 and December 2023. We identified nine cases with fetal CMV infection. The clinical data of the patients, gestational age at the time of diagnosis, serological, sonographic findings, and pregnancy outcomes were analyzed. A computer search of the database was made for the seroprevalance of CMV-IgM and CMV-IgG in our population. The CMV-IgM and IgG results of the 1235 patients who underwent CMV screening in the first trimester between September 2020 and December 2023 were evaluated. Fetal CMV infection was identified in nine patients. None of the 9 cases showed maternal CMV-IgM positivity. Seven of the 9 patients showed high IgG avidity index. Pregnant population had 98 % positivity for CMV-IgG. The evaluation of serologic tests for CMV is not straightforward in the second and third trimester. IgM and IgG avidity should be interpreted with caution in the second and third trimester. In the presence of ultrasound findings suggesting fetal CMV infection and CMV-IgG positivity, invasive diagnostic tests rather than serological test should be discussed with the patient, and non-primary infections should always be considered to minimize overlooked fetal cytomegalovirus infections and missed antiviral treatment opportunity.

SARS-CoV-2 infection and seropositivity among household contacts of laboratory confirmed cases of COVID-19 in residents of Delhi, India.

The transmission of respiratory pathogens, including SARS-CoV-2, is often facilitated through household contact. To better understand the transmission rate of COVID-19 among households and factors that affect viral clearance and seroconversion, a case-ascertained community-based prospective study was conducted between December 2020 and June 2021 on the urban population of the national capital region of India. The study collected nasopharyngeal swabs for SARS-CoV-2 RT-PCR on the 1st, 7th, 14th, and 28th day, and blood samples for antibody detection on the 1st, 14th, and 28th day from household contacts (HCs) of laboratory-confirmed COVID-19 cases. The study monitored the demographic data, symptoms, and outcomes of 417 participants, including 99 index cases and 318 contacts, for a period of 28 days. The results of the study showed that SARS-CoV-2 was easily spread within households, with a secondary infection rate of 44.3 %. In fact, almost 70 % of the contacts got infected within 1-2 days of identification of the index case, while 34 % remained asymptomatic. Sero-conversion was found in 35.6 % of the participants while 22.9 % did not produce antibodies after 28 days of infection. The study also revealed that females, spouses, older members, and primary care providers were at higher risk of getting infected in a home setting. However, approximately one-third of individuals in the younger age group managed to avoid infection. The study demonstrated that most infected individuals became RT-PCR negative within two weeks, although viral clearance was delayed in older patients and those with lower cycle threshold values in RT-PCR.

Characteristics and Clinical Prognosis of Septic Patients With Persistent Lymphopenia.

Background: Septic patients with persistent lymphopenia may be in an immunosuppressed state. Therefore, we evaluated and compared the clinical characteristics and outcomes of septic patients with persistent lymphopenia (≥2d) and those with nonpersistent lymphopenia. Methods: A retrospective cohort study was designed. A total of 1306 patients with sepsis who were attended to the First Affiliated Hospital of Dalian Medical University from March 2016 to August 2022 were included. The primary clinical outcome was 90d mortality. The secondary clinical outcomes were the length of stay, hospital mortality, 28d mortality, the incidence of secondary infection, and differences in clinical characteristics. Results: Among 1306 patients with sepsis, 913 (69.9%) patients developed persistent lymphopenia. Compared with patients with nonpersistent lymphopenia, patients with persistent lymphocytopenia were admitted to intensive care unit (75.7% vs 52.7%, P < .05), treated with mechanical ventilation (67.6% vs 39.2%, P < .05), positive rate of microbial culture pathogens (86.7% vs 71.2%, P < .05), SOFA [8.0 (6.0-10.0) vs 6.0 (4.0-8.0), P < .05], length of stay [17.0d (12.0-27.0) vs 13.0d (10.0-21.0), P < .05], hospital mortality (37.7% vs 24.2%, P < .05), 28d mortality (38.0% vs 22.9%, P < .05), and 90d mortality (51.2% vs 31.3%, P < .05) were higher. As the duration of lymphocytopenia increased, so did the mortality rate in hospital. In addition, the onset time of persistent lymphopenia was not associated with SOFA. But we found that the frequency of persistent lymphopenia during hospitalization was positively associated with SOFA. Conclusion: Septic patients with persistent lymphopenia have higher mortality, worse conditions, increased risk of secondary infection, and poor prognosis regardless of shock.

Esketamine mitigates cognitive impairment following exposure to LPS by modulating the intestinal flora/subdiaphragmatic vagus nerve/spleen axis.

INTRODUCTION: Susceptibility to secondary infection often increases after primary infection. Secondary infections can lead to more severe inflammatory injuries; however, the underlying mechanisms are not yet fully elucidated. OBJECTIVE: To investigate whether esketamine treatment immediately after primary lipopolysaccharide (LPS) exposure could alleviate cognitive impairment caused by secondary infection. METHODS: Mice were injected intraperitoneally (IP) with LPS (5 mg/kg) 10 days apart. Esketamine (10, 15, or 30 mg/kg) was administered IP immediately after the primary LPS injection. Splenectomy or subdiaphragmatic vagotomy (SDV) was performed 7 days before secondary LPS exposure or broad-spectrum antibiotic administration. RESULTS: Splenomegaly was observed after the primary LPS injection on Days 3 and 10. Splenomegaly was attenuated by treatment with 30 mg/kg esketamine. Esketamine treatment prevented increased plasma proinflammatory cytokines levels and cognitive dysfunction induced by secondary LPS exposure. Mice that underwent splenectomy or SDV had lower proinflammatory cytokines levels, higher hippocampal brain-derived neurotrophic factor (BDNF) levels, and improved cognitive function 1 day after secondary infection, which was not further improved by esketamine. Fecal microbiota transplantation (FMT) from endotoxic mice treated with esketamine attenuated hippocampal BDNF downregulation and cognitive dysfunction only in pseudo germ-free (PGF) mice without splenectomy. FMT with fecal suspensions from esketamine-treated endotoxic mice abrogated splenomegaly only in PGF mice without SDV. Blocking BDNF signaling blocked esketamine's ameliorating effects on secondary LPS exposure-induced cognitive dysfunction. CONCLUSION: The intestinal flora/subdiaphragmatic vagus nerve/spleen axis-mediated hippocampal BDNF downregulation significantly affected secondary LPS-induced systemic inflammation and cognitive dysfunction. Esketamine preserves cognitive function via this mechanism.

Photodynamic Suppression of Enterococcus Faecalis in Infected Root Canals with Indocyanine Green, TroloxTM and Near-Infrared Light.

Recently, our group showed that additional supplementation of Trolox™ (vitamin E analogue) can significantly enhance the antimicrobial photodynamic effect of the photosensitizer Indocyanine green (ICG). Up to now, the combined effect has not yet been investigated on Enterococcus faecalis in dental root canals. In the present in vitro study, eighty human root canals were inoculated with E. faecalis and subsequently subjected to antimicrobial Photodynamic Therapy (aPDT) using ICG (250, 500, 1000 µg/mL) and near-infrared laser light (NIR, 808 nm, 100 Jcm-2). Trolox™ at concentrations of 6 mM was additionally applied. As a positive control, irrigation with 3% NaOCl was used. After aPDT, root canals were manually enlarged and the collected dentin debris was subjected to microbial culture analysis. Bacterial invasion into the dentinal tubules was verified for a distance of 300 µm. aPDT caused significant suppression of E. faecalis up to a maximum of 2.9 log counts (ICG 250 µg/mL). Additional application of TroloxTM resulted in increased antibacterial activity for aPDT with ICG 500 µg/mL. The efficiency of aPDT was comparable to NaOCl-irrigation inside the dentinal tubules. In conclusion, ICG significantly suppressed E. faecalis. Additional application of TroloxTM showed only minor enhancement. Future studies should also address the effects of TroloxTM on other photodynamic systems.

Transmissibility of severe acute respiratory syndrome coronavirus 2 among household contacts of coronavirus disease 2019-positive patients: A community-based study in India.

BACKGROUND: This study identified the risk factors for severe acute respiratory syndrome coronavirus 2 infection among household contacts of index patients and determined the incubation period (IP), serial interval, and estimates of secondary infection rate in Kerala, India. METHODS: We conducted a cohort study in three districts of Kerala among the inhabitants of households of reverse transcriptase polymerase chain reaction-positive coronavirus disease 2019 patients between January and July 2021. About 147 index patients and 362 household contacts were followed up for 28 days to determine reverse transcriptase polymerase chain reaction positivity and the presence of total antibodies against SARS-CoV-2 on days 1, 7, 14, and 28. RESULTS: The mean IP, serial interval, and generation time were 1.6, 3, and 3.9 days, respectively. The secondary infection rate at 14 days was 43.0%. According to multivariable regression analysis persons who worked outside the home were protected (adjusted odds ratio [aOR], 0.45; 95% confidence interval [CI], 0.24-0.85), whereas those who had kissed the coronavirus disease 2019-positive patients during illness were more than twice at risk of infection (aOR, 2.23; 95% CI, 1.01-5.2) than those who had not kissed the patients. Sharing a toilet with the index patient increased the risk by more than twice (aOR, 2.5; 95% CI, 1.42-4.64) than not sharing a toilet. However, the contacts who reported using masks (aOR, 2.5; 95% CI, 1.4-4.4) were at a higher risk of infection in household settings. CONCLUSIONS: Household settings have a high secondary infection rate and the changing transmissibility dynamics such as IP, serial interval should be considered in the prevention and control of SARS-CoV-2.

Monitoring the Spread of Grapevine Viruses in Vineyards of Contrasting Agronomic Practices: A Metagenomic Investigation.

This study investigated the transmission of grapevine viruses, specifically grapevine red blotch virus (GRBV) and grapevine Pinot gris virus (GPGV), in vineyards in Niagara Region, Ontario, Canada. Forty sentinel vines that were confirmed free of GRBV and GPGV by both high-throughput sequencing (HTS) and endpoint polymerase chain reaction (PCR) were introduced to two vineyards (one organic and one conventional) that were heavily infected with both GRBV and GPGV. Four months post-introduction, the sentinel vines were relocated to a phytotron. The HTS results from 15 months post-introduction revealed a widespread infection of GPGV among the sentinel vines but did not detect any GRBV. The GPGV infection rate of sentinel vines in the organic vineyard (13/18) was higher than in the conventional vineyard (1/19). The possibility of an alternative viral reservoir was assessed by testing the most abundant plants in between rows (Medicago sativa, Trifolium repens, Cirsium arvense and Taraxacum officinale), perennial plants in border areas (Fraxinus americana, Ulmus americana, Rhamnus cathartica) and wild grape (unknown Vitis sp.). The HTS result showed that cover crops and perennial plants did not harbor any grapevine viruses, while 4/5 wild grapes tested positive for GPGV but not GRBV. A pairwise sequence identity analysis revealed high similarities between the GPGV isolates found in the established vines on the vineyard and the newly contracted GPGV isolates in the sentinel vines, implicating a recent transmission event. This work provides novel insights into the spread of grapevine viruses in Niagara Region and is also the first direct proof of the spread of GPGV in natural vineyard conditions in North America.