Clinical and etiological analysis of co-infections and secondary infections in COVID-19 patients: An observational study

Disease burden and macrolide resistance of Mycoplasma pneumoniae infection in adults in the Asia-Pacific region

OBJECTIVES

In the Asia-Pacific region, Mycoplasma pneumoniae (MP) could be a notable pathogen responsible for adult community-acquired pneumonia (CAP), with varying prevalence rates. This comprehensive review aimed to explore the epidemiology, clinical manifestations, macrolide resistance, and molecular characteristics of MP in adults across several countries in Asia.

METHODS

PubMed, Embase, and Google Scholar were searched for relevant articles from 2010-2023 based on the following keywords: adult and Mycoplasma pneumoniae.

RESULTS

The prevalence of MP in CAP patients in these countries ranged from 2.1% in Korea to 25.5% in Japan. Macrolide resistance was prominent, particularly in China, with rates ranging 26.9-100%. Clinical manifestations of MP infection included protean extrapulmonary manifestations, and complications such as rhabdomyolysis and thrombocytopenia. Molecular characteristics, especially the multiple locus variable-number tandem-repeat analysis type 4/5/7/2, remained predominant across various countries, emphasising the importance of ongoing surveillance.

CONCLUSIONS

This review highlights the urgent need for continued monitoring of MP infections, macrolide resistance, and molecular characteristics to inform effective prevention and treatment strategies in the Asia-Pacific region.

Clostridioides difficile infection following COVID-19: A nationwide analysis using routine surveillance data in Wales

BACKGROUND

CDI incidence has increased in Wales from summer 2020 and has remained elevated. There is evidence of poorer outcomes from concurrent CDI and COVID-19 infections, but it is not clear if infection with COVID-19 directly impacts likelihood of CDI infection.

AIM

We investigated the relationship between CDI and COVID-19 and the impact of secondary infections.

METHODS

We conducted two analytical studies using routine surveillance data: i) population level ecological case control study comparing CDI cases in the Welsh population by SARS-COV-2 exposure in the previous 90 days, ii) cohort study of COVID-19 cases by secondary infection presence, investigating CDI development within 90 days.

FINDINGS

Case control: 12% (196/1645) of CDI cases had prior COVID-19 and were twice as likely to have had COVID-19 compared to general population controls, when controlling for other infection history (OR 2.1, CI 1.8-2.5, p<0.0001). CDI cases were 8 times more likely to have had other infections, independent of COVID-19 history (OR 8.0, CI 7.0-9.0, p<0.001).

COHORT STUDY

2% (2,255/137,620)) of the COVID-19 cohort developed >1 secondary infection, and <1% (185/137620) developed CDI within 90 days. CDI risk was four times higher in those with secondary infections, after age and sex adjustment (RR 4.6, CI 3.1 - 6.1, p<0.001). CDI risk increased with age and did not differ by sex.

CONCLUSIONS

Findings suggest a relationship between COVID-19 and CDI. However, incidence of CDI following COVID-19 was a rare outcome generally, suggesting other factors are likely contributing to the increased rates of CDI observed since 2020.

Aprotinin (I): Understanding the Role of Host Proteases in COVID-19 and the Importance of Pharmacologically Regulating Their Function

Proteases are produced and released in the mucosal cells of the respiratory tract and have important physiological functions, for example, maintaining airway humidification to allow proper gas exchange. The infectious mechanism of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), takes advantage of host proteases in two ways: to change the spatial conformation of the spike (S) protein via endoproteolysis (e.g., transmembrane serine protease type 2 (TMPRSS2)) and as a target to anchor to epithelial cells (e.g., angiotensin-converting enzyme 2 (ACE2)). This infectious process leads to an imbalance in the mucosa between the release and action of proteases versus regulation by anti-proteases, which contributes to the exacerbation of the inflammatory and prothrombotic response in COVID-19. In this article, we describe the most important proteases that are affected in COVID-19, and how their overactivation affects the three main physiological systems in which they participate: the complement system and the kinin-kallikrein system (KKS), which both form part of the contact system of innate immunity, and the renin-angiotensin-aldosterone system (RAAS). We aim to elucidate the pathophysiological bases of COVID-19 in the context of the imbalance between the action of proteases and anti-proteases to understand the mechanism of aprotinin action (a panprotease inhibitor). In a second-part review, titled "Aprotinin (II): Inhalational Administration for the Treatment of COVID-19 and Other Viral Conditions", we explain in depth the pharmacodynamics, pharmacokinetics, toxicity, and use of aprotinin as an antiviral drug.

Nasal carriage of virulent and multidrug resistant Staphylococcus aureus: a possible comorbidity of COVID-19

BACKGROUND

Staphylococcus aureus (S. aureus) associated with COVID-19 has not been well documented. This cross-sectional study evaluated the association between nasal S. aureus carriage and COVID-19.

METHODS AND RESULTS

Nasopharyngeal samples were collected from 391 participants presenting for COVID-19 test in Lagos, Nigeria, and S. aureus was isolated from the samples. Antimicrobial susceptibility test was done by disc diffusion method. All S. aureus isolates were screened for the presence of mecA, panton-valentine leucocidin (PVL) and toxic shock syndrome toxin (TSST) virulence genes by polymerase chain reaction. Staphylococcal protein A (spa) typing was conducted for all the isolates. Participants with COVID-19 had double the prevalence of S. aureus (42.86%) compared to those who tested negative (20.54%). A significant association was seen between S. aureus nasal carriage and COVID-19 (p = 0.004). Antimicrobial sensitivity results showed resistance to oxacillin (100%), cefoxitin (53%), and vancomycin (98.7%). However, only 41% of the isolates harbored the mecA gene, with SCCmecV being the most common SCCmec type. There was no association between the carriage of virulence genes and COVID-19. A total of 23 Spa types were detected, with t13249 and t095 being the two most common spa types.

CONCLUSION

This study examined the association between nasal S. aureus carriage and SARS-COV-2 infection. Further research is required to fully explore the implications of S. aureus co-infection with COVID-19.

Changes in clinical parameters and inflammatory markers after blood culture collection facilitate early identification of positive culture in adult patients with COVID-19 and clinically suspected bloodstream infection

OBJECTIVE

We explored whether changes in clinical parameters and inflammatory markers can facilitate early identification of positive blood culture in adult patients with COVID-19 and clinically suspected bloodstream infection (BSI).

METHODS

This single-center retrospective study enrolled 20 adult patients with COVID-19 admitted to the intensive care unit who underwent blood culture for clinically suspected BSI (February 2020-November 2021). We divided patients into positive (Pos) and negative blood culture groups. Clinical parameters and inflammatory markers were obtained from medical records between blood culture collection and the first positive or negative result and compared between groups on different days.

RESULTS

Patients in the positive culture group had significantly older age and higher D-dimer, immunoglobulin 6 (IL-6), and Sequential Organ Failure Assessment score as well as lower albumin (ALB). The area under the receiver operating characteristic curve (AUC) was 0.865 for IL-6, D-dimer and ALB on the first day after blood culture collection; the AUC was 0.979 for IL-6, IL-10, D-dimer, and C-reactive protein on the second day after blood culture collection.

CONCLUSION

Changes in clinical parameters and inflammatory markers after blood culture collection may facilitate early identification of positive culture in adult patients with COVID-19 and clinically suspected BSI.

The Impact of Viral and Bacterial Co-Infections and Home Antibiotic Treatment in SARS-CoV-2 Hospitalized Patients at the Policlinico Tor Vergata Hospital, Rome, Italy

Co-infections during COVID-19 may worsen patients' outcomes. This study reports the results of a screening assessing the presence of co-infections among patients hospitalized for SARS-CoV-2 infection in the Infectious Diseases-Ward of the Policlinico Tor Vergata Hospital, Rome, Italy, from 1 January to 31 December 2021. Data on hepatitis B and C virus, urinary antigens for legionella pneumophila and streptococcus pneumoniae, pharyngeal swab for respiratory viruses, QuantiFERON®-TB Gold Plus assay (QFT-P), blood cultures and pre-hospitalization antibiotic prescription were recorded. A total of 482 patients were included, 61% males, median age of 65 years (IQR 52-77), median Charlson comorbidity index of 4 (IQR 2-5). The mortality rate was 12.4%; 366 patients needed oxygen supply. In total, 151 patients (31.3%) received home antibiotics without any association with the outcome. No significant association between mortality and the positivity of viral hepatitis markers was found. Out of 442 patients, 125 had an indeterminate QFT-P, associated with increased mortality. SARS-CoV-2 was the only respiratory virus detected among 389 pharyngeal swabs; 15/428 patients were positive for S. pneumoniae; none for L. pneumophila. In total, 237 blood cultures were drawn within 48 h from hospital admission: 28 were positive and associated with increased mortality. In our cohort, bacterial and viral co-infections in COVID-19 hospitalized patients were rare and not associated with higher mortality.

Prevalence of early bacterial co-infection in hospitalized patients with COVID-19 pneumonia: a retrospective study

BACKGROUND

Identification of bacterial co-infection is crucial in determining outcomes of patients with coronavirus disease 2019 (COVID-19) pneumonia. The present study aims to evaluate the prevalence and associated factors of early bacterial co-infection in patients with COVID-19 pneumonia.

METHODS

The present study is a retrospective study. Patients with COVID-19 pneumonia, who were admitted to Siriraj Hospital between April 1 and August 31, 2021, were randomly enrolled and classified as the "Early bacterial co-infection" group, defined by an infection occurring within the first 48 hours after admission, and the "Unlikely early bacterial co-infection" group.

RESULTS

A total of 245 patients were enrolled. The prevalence of early bacterial co-infection was 15.5%. Chest X-rays showed characteristic findings for COVID-19 pneumonia in 37.6%. The median Brixia chest X-ray scores and C-reactive protein levels were significantly higher in the Early bacterial co-infection group. The most common causative pathogens included Staphylococcus aureus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. Patients with early bacterial co-infection had a significantly higher all-cause mortality compared to the Unlikely early bacterial co-infection group (P=0.012). The Charlson Comorbidity Index ≥4, high level of respiratory support, and mass-liked or diffuse opacities on chest X-rays were independent factors associated with the early bacterial co-infection.

CONCLUSIONS

The prevalence of early bacterial co-infection in patients with COVID-19 pneumonia was low but it was associated with mortality. There is insufficient evidence to support the empirical use of antibiotics in these patients. A further prospective study is required to confirm the results of the present study.

An Observational Study to Develop a Predictive Model for Bacterial Pneumonia Diagnosis in Severe COVID-19 Patients-C19-PNEUMOSCORE

In COVID-19 patients, antibiotics overuse is still an issue. A predictive scoring model for the diagnosis of bacterial pneumonia at intensive care unit (ICU) admission would be a useful stewardship tool. We performed a multicenter observational study including 331 COVID-19 patients requiring invasive mechanical ventilation at ICU admission; 179 patients with bacterial pneumonia; and 152 displaying negative lower-respiratory samplings. A multivariable logistic regression model was built to identify predictors of pulmonary co-infections, and a composite risk score was developed using β-coefficients. We identified seven variables as predictors of bacterial pneumonia: vaccination status (OR 7.01; 95% CI, 1.73-28.39); chronic kidney disease (OR 3.16; 95% CI, 1.15-8.71); pre-ICU hospital length of stay ≥ 5 days (OR 1.94; 95% CI, 1.11-3.4); neutrophils ≥ 9.41 × 10⁹/L (OR 1.96; 95% CI, 1.16-3.30); procalcitonin ≥ 0.2 ng/mL (OR 5.09; 95% CI, 2.93-8.84); C-reactive protein ≥ 107.6 mg/L (OR 1.99; 95% CI, 1.15-3.46); and Brixia chest X-ray score ≥ 9 (OR 2.03; 95% CI, 1.19-3.45). A predictive score (C19-PNEUMOSCORE), ranging from 0 to 9, was obtained by assigning one point to each variable, except from procalcitonin and vaccine status, which gained two points each. At a cut-off of ≥3, the model exhibited a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 84.9%, 55.9%, 69.4%, 75.9%, and 71.6%, respectively. C19-PNEUMOSCORE may be an easy-to-use bedside composite tool for the early identification of severe COVID-19 patients with pulmonary bacterial co-infection at ICU admission. Its implementation may help clinicians to optimize antibiotics administration in this setting.

Clinical metagenomics-challenges and future prospects

Infections lacking precise diagnosis are often caused by a rare or uncharacterized pathogen, a combination of pathogens, or a known pathogen carrying undocumented or newly acquired genes. Despite medical advances in infectious disease diagnostics, many patients still experience mortality or long-term consequences due to undiagnosed or misdiagnosed infections. Thus, there is a need for an exhaustive and universal diagnostic strategy to reduce the fraction of undocumented infections. Compared to conventional diagnostics, metagenomic next-generation sequencing (mNGS) is a promising, culture-independent sequencing technology that is sensitive to detecting rare, novel, and unexpected pathogens with no preconception. Despite the fact that several studies and case reports have identified the effectiveness of mNGS in improving clinical diagnosis, there are obvious shortcomings in terms of sensitivity, specificity, costs, standardization of bioinformatic pipelines, and interpretation of findings that limit the integration of mNGS into clinical practice. Therefore, physicians must understand the potential benefits and drawbacks of mNGS when applying it to clinical practice. In this review, we will examine the current accomplishments, efficacy, and restrictions of mNGS in relation to conventional diagnostic methods. Furthermore, we will suggest potential approaches to enhance mNGS to its maximum capacity as a clinical diagnostic tool for identifying severe infections.

WssI from the Gram-Negative Bacterial Cellulose Synthase is an O-acetyltransferase that Acts on Cello-oligomers with Several Acetyl Donor Substrates

In microbial biofilms, bacterial cells are encased in a self-produced matrix of polymers (e.g., exopolysaccharides) that enable surface adherence and protect against environmental stressors. For example, the wrinkly spreader phenotype of Pseudomonas fluorescens colonizes food/water sources and human tissue to form robust biofilms that can spread across surfaces. This biofilm largely consists of bacterial cellulose produced by the cellulose synthase proteins encoded by the wss operon, which also occurs in other species, including pathogenic Achromobacter species. Although phenotypic mutant analysis of the wssFGHI genes has previously shown that they are responsible for acetylation of bacterial cellulose, their specific roles remain unknown and distinct from the recently identified cellulose phosphoethanolamine modification found in other species. Here we have purified the C-terminal soluble form of WssI from P. fluorescens and A. insuavis and demonstrated acetyl-esterase activity with chromogenic substrates. The kinetic parameters (k_cat/K_M values of 13 and 8.0 M^-1∙ s^-1, respectively) indicate that these enzymes are up to four times more catalytically efficient than the closest characterized homolog, AlgJ from the alginate synthase. Unlike AlgJ and its cognate alginate polymer, WssI also demonstrated acetyltransferase activity onto cellulose oligomers (e.g., cellotetraose to cellohexaose) with multiple acetyl-donor substrates (pNP-Ac, MU-Ac and acetyl-CoA). Finally, a high-throughput screen identified three low micromolar WssI inhibitors that may be useful for chemically interrogating cellulose acetylation and biofilm formation.

Recommendations and guidelines for the diagnosis and management of Coronavirus Disease-19 (COVID-19) associated bacterial and fungal infections in Taiwan

Coronavirus disease-19 (COVID-19) is an emerging infectious disease caused by SARS-CoV-2 that has rapidly evolved into a pandemic to cause over 600 million infections and more than 6.6 million deaths up to Nov 25, 2022. COVID-19 carries a high mortality rate in severe cases. Co-infections and secondary infections with other micro-organisms, such as bacterial and fungus, further increases the mortality and complicates the diagnosis and management of COVID-19. The current guideline provides guidance to physicians for the management and treatment of patients with COVID-19 associated bacterial and fungal infections, including COVID-19 associated bacterial infections (CABI), pulmonary aspergillosis (CAPA), candidiasis (CAC) and mucormycosis (CAM). Recommendations were drafted by the 7th Guidelines Recommendations for Evidence-based Antimicrobial agents use Taiwan (GREAT) working group after review of the current evidence, using the grading of recommendations assessment, development, and evaluation (GRADE) methodology. A nationwide expert panel reviewed the recommendations in March 2022, and the guideline was endorsed by the Infectious Diseases Society of Taiwan (IDST). This guideline includes the epidemiology, diagnostic methods and treatment recommendations for COVID-19 associated infections. The aim of this guideline is to provide guidance to physicians who are involved in the medical care for patients with COVID-19 during the ongoing COVID-19 pandemic.

[Metagenomic next-generation sequencing of plasma for the identification of bloodstream infectious pathogens in severe aplastic anemia]

Objective: To analyze the diagnostic value of cell-free plasma metagenomic next-generation sequencing (mNGS) pathogen identification for severe aplastic anemia (SAA) bloodstream infection. Methods: From February 2021 to February 2022, mNGS and conventional detection methods (blood culture, etc.) were used to detect 33 samples from 29 consecutive AA patients admitted to the Anemia Diagnosis and Treatment Center of the Hematology Hospital of the Chinese Academy of Medical Sciences to assess the diagnostic consistency of mNGS and conventional detection, as well as the impact on clinical treatment benefits and clinical accuracy. Results: ①Among the 33 samples evaluated by mNGS and conventional detection methods, 25 cases (75.76%) carried potential pathogenic microorganisms. A total of 72 pathogenic microorganisms were identified from all cases, of which 65 (90.28%) were detected only by mNGS. ②All 33 cases were evaluated for diagnostic consistency, of which 2 cases (6.06%) were Composite, 18 cases (54.55%) were mNGS only, 2 cases (6.06%) were Conventional method only, 1 case (3.03%) was both common compliances (mNGS/Conventional testing) , and 10 cases (30.3%) were completely non-conforming (None) . ③All 33 cases were evaluated for clinical treatment benefit. Among them, 8 cases (24.24%) received Initiation of targeted treatment, 1 case (3.03%) received Treatment de-escalation, 13 cases (39.39%) received Confirmation, and the remaining 11 cases (33.33%) received No clinical benefit. ④ The sensitivity of 80.77%, specificity of 70.00%, positive predictive value of 63.64%, negative predictive value of 84.85%, positive likelihood ratio of 2.692, and negative likelihood ratio of 0.275 distinguished mNGS from conventional detection methods (21/12 vs 5/28, P<0.001) . Conclusion: mNGS can not only contribute to accurately diagnosing bloodstream infection in patients with aplastic anemia, but can also help to guide accurate anti-infection treatment, and the clinical accuracy is high.

Antimicrobial resistance in patients with COVID-19: a systematic review and meta-analysis

BACKGROUND

Frequent use of antibiotics in patients with COVID-19 threatens to exacerbate antimicrobial resistance. We aimed to establish the prevalence and predictors of bacterial infections and antimicrobial resistance in patients with COVID-19.

METHODS

We did a systematic review and meta-analysis of studies of bacterial co-infections (identified within ≤48 h of presentation) and secondary infections (>48 h after presentation) in outpatients or hospitalised patients with COVID-19. We searched the WHO COVID-19 Research Database to identify cohort studies, case series, case-control trials, and randomised controlled trials with populations of at least 50 patients published in any language between Jan 1, 2019, and Dec 1, 2021. Reviews, editorials, letters, pre-prints, and conference proceedings were excluded, as were studies in which bacterial infection was not microbiologically confirmed (or confirmed via nasopharyngeal swab only). We screened titles and abstracts of papers identified by our search, and then assessed the full text of potentially relevant articles. We reported the pooled prevalence of bacterial infections and antimicrobial resistance by doing a random-effects meta-analysis and meta-regression. Our primary outcomes were the prevalence of bacterial co-infection and secondary infection, and the prevalence of antibiotic-resistant pathogens among patients with laboratory-confirmed COVID-19 and bacterial infections. The study protocol was registered with PROSPERO (CRD42021297344).

FINDINGS

We included 148 studies of 362  976 patients, which were done between December, 2019, and May, 2021. The prevalence of bacterial co-infection was 5·3% (95% CI 3·8-7·4), whereas the prevalence of secondary bacterial infection was 18·4% (14·0-23·7). 42 (28%) studies included comprehensive data for the prevalence of antimicrobial resistance among bacterial infections. Among people with bacterial infections, the proportion of infections that were resistant to antimicrobials was 60·8% (95% CI 38·6-79·3), and the proportion of isolates that were resistant was 37·5% (26·9-49·5). Heterogeneity in the reported prevalence of antimicrobial resistance in organisms was substantial (I2=95%).

INTERPRETATION

Although infrequently assessed, antimicrobial resistance is highly prevalent in patients with COVID-19 and bacterial infections. Future research and surveillance assessing the effect of COVID-19 on antimicrobial resistance at the patient and population level are urgently needed.

FUNDING

WHO.

Bacterial coinfections in hospitalized children with COVID-19 during the SARS-CoV-2 Omicron BA.2 variant pandemic in Taiwan

Background

Bacterial coinfections have been widely recognized in adults with coronavirus disease 2019 (COVID-19). However, bacterial coinfections in hospitalized children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have not been sufficiently researched. This study aimed to determine the clinical presentations and risk factors for bacterial coinfections of pediatric inpatients during the SARS-CoV-2 Omicron BA.2 variant pandemic.

Methods

This retrospective, observational study included patients younger than 18 years of age who were hospitalized for COVID-19 confirmed by polymerase chain reaction (PCR) or antigen rapid tests during the SARS-CoV-2 Omicron BA.2 variant pandemic. Data and outcomes of these patients with or without bacterial coinfections were compared.

Results

During this study period, 161 children with confirmed COVID-19 were hospitalized. Twenty-four had bacterial coinfections. The most frequently reported concurrent diagnosis was bacterial enteritis, followed by lower respiratory tract infections. Children with bacterial coinfections had higher white blood cell (WBC) counts and PCR cycle threshold values. The bacterial coinfection group comprised a relatively greater proportion of patients who required high-flow nasal cannula oxygen and remdesivir. The length of stay in the hospital and that in the intensive care unit were longer for children with COVID-19 with bacterial coinfections. Mortality was not observed in either group. Abdominal pain, diarrhea, and comorbidity with neurologic illnesses were risk factors for bacterial coinfections with COVID-19.

Conclusion

This study provides clinicians with reference points for the detection of COVID-19 in children and its possible association with bacterial infections. Children with COVID-19 and neurologic diseases who present with abdominal pain or diarrhea are at risk of bacterial coinfections. Prolonged fever duration and higher PCR test cycle threshold values, WBC levels, and high-sensitivity C-reactive protein (hsCRP) levels may indicate bacterial coinfections in children with COVID-19.

Structure of the AlgKX modification and secretion complex required for alginate production and biofilm attachment in Pseudomonas aeruginosa

Synthase-dependent secretion systems are a conserved mechanism for producing exopolysaccharides in Gram-negative bacteria. Although widely studied, it is not well understood how these systems are organized to coordinate polymer biosynthesis, modification, and export across both membranes and the peptidoglycan. To investigate how synthase-dependent secretion systems produce polymer at a molecular level, we determined the crystal structure of the AlgK-AlgX (AlgKX) complex involved in Pseudomonas aeruginosa alginate exopolysaccharide acetylation and export. We demonstrate that AlgKX directly binds alginate oligosaccharides and that formation of the complex is vital for polymer production and biofilm attachment. Finally, we propose a structural model for the AlgEKX outer membrane modification and secretion complex. Together, our study provides insight into how alginate biosynthesis proteins coordinate production of a key exopolysaccharide involved in establishing persistent Pseudomonas lung infections.

Analysis of bronchoalveolar lavage fluid metatranscriptomes among patients with COVID-19 disease

To better understand the potential relationship between COVID-19 disease and hologenome microbial community dynamics and functional profiles, we conducted a multivariate taxonomic and functional microbiome comparison of publicly available human bronchoalveolar lavage fluid (BALF) metatranscriptome samples amongst COVID-19 (n = 32), community acquired pneumonia (CAP) (n = 25), and uninfected samples (n = 29). We then performed a stratified analysis based on mortality amongst the COVID-19 cohort with known outcomes of deceased (n = 10) versus survived (n = 15). Our overarching hypothesis was that there are detectable and functionally significant relationships between BALF microbial metatranscriptomes and the severity of COVID-19 disease onset and progression. We observed 34 functionally discriminant gene ontology (GO) terms in COVID-19 disease compared to the CAP and uninfected cohorts, and 21 GO terms functionally discriminant to COVID-19 mortality (q < 0.05). GO terms enriched in the COVID-19 disease cohort included hydrolase activity, and significant GO terms under the parental terms of biological regulation, viral process, and interspecies interaction between organisms. Notable GO terms associated with COVID-19 mortality included nucleobase-containing compound biosynthetic process, organonitrogen compound catabolic process, pyrimidine-containing compound biosynthetic process, and DNA recombination, RNA binding, magnesium and zinc ion binding, oxidoreductase activity, and endopeptidase activity. A Dirichlet multinomial mixtures clustering analysis resulted in a best model fit using three distinct clusters that were significantly associated with COVID-19 disease and mortality. We additionally observed discriminant taxonomic differences associated with COVID-19 disease and mortality in the genus Sphingomonas, belonging to the Sphingomonadacae family, Variovorax, belonging to the Comamonadaceae family, and in the class Bacteroidia, belonging to the order Bacteroidales. To our knowledge, this is the first study to evaluate significant differences in taxonomic and functional signatures between BALF metatranscriptomes from COVID-19, CAP, and uninfected cohorts, as well as associating these taxa and microbial gene functions with COVID-19 mortality. Collectively, while this data does not speak to causality nor directionality of the association, it does demonstrate a significant relationship between the human microbiome and COVID-19. The results from this study have rendered testable hypotheses that warrant further investigation to better understand the causality and directionality of host-microbiome-pathogen interactions.

The current landscape of microRNAs (miRNAs) in bacterial pneumonia: opportunities and challenges

MicroRNAs (miRNAs), which were initially discovered in Caenorhabditis elegans, can regulate gene expression by recognizing cognate sequences and interfering with the transcriptional or translational machinery. The application of bioinformatics tools for structural analysis and target prediction has largely driven the investigation of certain miRNAs. Notably, it has been found that certain miRNAs which are widely involved in the inflammatory response and immune regulation are closely associated with the occurrence, development, and outcome of bacterial pneumonia. It has been shown that certain miRNA techniques can be used to identify related targets and explore associated signal transduction pathways. This enhances the understanding of bacterial pneumonia, notably for “refractory” or drug-resistant bacterial pneumonia. Although these miRNA-based methods may provide a basis for the clinical diagnosis and treatment of this disease, they still face various challenges, such as low sensitivity, poor specificity, low silencing efficiency, off-target effects, and toxic reactions. The opportunities and challenges of these methods have been completely reviewed, notably in bacterial pneumonia. With the continuous improvement of the current technology, the miRNA-based methods may surmount the aforementioned limitations, providing promising support for the clinical diagnosis and treatment of “refractory” or drug-resistant bacterial pneumonia.

Coronavirus disease 2019 (COVID-19) associated bacterial coinfection: Incidence, diagnosis and treatment

Coronavirus disease 2019 (COVID-19) emerged as a pandemic that spread rapidly around the world, causing nearly 500 billion infections and more than 6 million deaths to date. During the first wave of the pandemic, empirical antibiotics was prescribed in over 70% of hospitalized COVID-19 patients. However, research now shows a low incidence rate of bacterial coinfection in hospitalized COVID-19 patients, between 2.5% and 5.1%. The rate of secondary infections was 3.7% in overall, but can be as high as 41.9% in the intensive care units. Over-prescription of antibiotics to treat COVID-19 patients fueled the ongoing antimicrobial resistance globally. Diagnosis of bacterial coinfection is challenging due to indistinguishable clinical presentations with overlapping lower respiratory tract symptoms such as fever, cough and dyspnea. Other diagnostic methods include conventional culture, diagnostic syndromic testing, serology test and biomarkers. COVID-19 patients with bacterial coinfection or secondary infection have a higher in-hospital mortality and longer length of stay, timely and appropriate antibiotic use aided by accurate diagnosis is crucial to improve patient outcome and prevent antimicrobial resistance.

Prevalence of bacterial coinfection and patterns of antibiotics prescribing in patients with COVID-19: A systematic review and meta-analysis

BACKGROUND

Evidence around prevalence of bacterial coinfection and pattern of antibiotic use in COVID-19 is controversial although high prevalence rates of bacterial coinfection have been reported in previous similar global viral respiratory pandemics. Early data on the prevalence of antibiotic prescribing in COVID-19 indicates conflicting low and high prevalence of antibiotic prescribing which challenges antimicrobial stewardship programmes and increases risk of antimicrobial resistance (AMR).

AIM

To determine current prevalence of bacterial coinfection and antibiotic prescribing in COVID-19 patients.

DATA SOURCE

OVID MEDLINE, OVID EMBASE, Cochrane and MedRxiv between January 2020 and June 2021.

STUDY ELIGIBILITY

English language studies of laboratory-confirmed COVID-19 patients which reported (a) prevalence of bacterial coinfection and/or (b) prevalence of antibiotic prescribing with no restrictions to study designs or healthcare setting.

PARTICIPANTS

Adults (aged ≥ 18 years) with RT-PCR confirmed diagnosis of COVID-19, regardless of study setting.

METHODS

Systematic review and meta-analysis. Proportion (prevalence) data was pooled using random effects meta-analysis approach; and stratified based on region and study design.

RESULTS

A total of 1058 studies were screened, of which 22, hospital-based studies were eligible, compromising 76,176 of COVID-19 patients. Pooled estimates for the prevalence of bacterial co-infection and antibiotic use were 5.62% (95% CI 2.26-10.31) and 61.77% (CI 50.95-70.90), respectively. Sub-group analysis by region demonstrated that bacterial co-infection was more prevalent in North American studies (7.89%, 95% CI 3.30-14.18).

CONCLUSION

Prevalence of bacterial coinfection in COVID-19 is low, yet prevalence of antibiotic prescribing is high, indicating the need for targeted COVID-19 antimicrobial stewardship initiatives to reduce the global threat of AMR.

Long-read 16S-seq reveals nasopharynx microbial dysbiosis and enrichment of Mycobacterium and Mycoplasma in COVID-19 patients: a potential source of co-infection

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a major global health concern. This virus infects the upper respiratory tract and causes pneumonia-like symptoms. So far, few studies have shown alterations in nasopharyngeal (NP) microbial diversity, enrichment of opportunistic pathogens and their role in co-infections during respiratory infections. Therefore, we hypothesized that microbial diversity changes, with increase in the population of opportunistic pathogens, during SARS-CoV2 infection in the nasopharynx, which may be involved in co-infection in COVID-19 patients. The 16S rRNA variable regions, V1-V9, of NP samples of control and COVID-19 (symptomatic and asymptomatic) patients were sequenced using the Oxford Nanopore™ technology. Comprehensive bioinformatics analysis for determining alpha/beta diversities, non-metric multidimensional scaling, correlation studies, canonical correspondence analysis, linear discriminate analysis, and dysbiosis index were used to analyze the control and COVID-19-specific NP microbiomes. We observed significant dysbiosis in the COVID-19 NP microbiome with an increase in the abundance of opportunistic pathogens at genus and species levels in asymptomatic/symptomatic patients. The significant abundance of Mycobacteria spp. and Mycoplasma spp. in symptomatic patients suggests their association and role in co-infections in COVID-19 patients. Furthermore, we found strong correlation of enrichment of Mycobacteria and Mycoplasma with the occurrences of chest pain and fever in symptomatic COVID-19 patients. This is the first study from India to show the abundance of Mycobacteria and Mycoplasma opportunistic pathogens in non-hospitalized COVID-19 patients and their relationship with symptoms, indicating the possibility of co-infections.

SARS-CoV-2-Legionella Co-Infections: A Systematic Review and Meta-Analysis (2020-2021)

Legionnaires' Disease (LD) is a severe, sometimes fatal interstitial pneumonia due to Legionella pneumophila. Since the inception of the SARS-CoV-2 pandemic, some contradictory reports about the effects of lockdown measures on its epidemiology have been published, but no summary evidence has been collected to date. Therefore, we searched two different databases (PubMed and EMBASE) focusing on studies that reported the occurrence of LD among SARS-CoV-2 cases. Data were extracted using a standardized assessment form, and the results of such analyses were systematically reported, summarized, and compared. We identified a total of 38 articles, including 27 observational studies (either prospective or retrospective ones), 10 case reports, and 1 case series. Overall, data on 10,936 SARS-CoV-2 cases were included in the analyses. Of them, 5035 (46.0%) were tested for Legionella either through urinary antigen test or PCR, with 18 positive cases (0.4%). A pooled prevalence of 0.288% (95% Confidence Interval (95% CI) 0.129-0.641), was eventually calculated. Moreover, detailed data on 19 co-infections LD + SARS-CoV-2 were obtained (males: 84.2%; mean age: 61.9 years, range 35 to 83; 78.9% with 1 or more underlying comorbidities), including 16 (84.2%) admissions to the ICU, with a Case Fatality Ratio of 26.3%. In summary, our analyses suggest that the occurrence of SARS-CoV-2-Legionella infections may represent a relatively rare but not irrelevant event, and incident cases are characterized by a dismal prognosis.

Pseudomonas aeruginosa modulates alginate biosynthesis and type VI secretion system in two critically ill COVID-19 patients

Background

COVID-19 pneumonia has caused huge impact on the health of infected patients and associated with high morbidity and mortality. Shift in the lung microbial ecology upon such viral infection often worsens the disease and increases host susceptibility to superinfections. Bacterial superinfection contributes to the aggravation of COVID-19 and poses a great challenge to clinical treatments. An in-depth investigation on superinfecting bacteria in COVID-19 patients might facilitate understanding of lung microenvironment post virus infections and superinfection mechanism.

Results

We analyzed the adaptation of two pairs of P. aeruginosa strains with the same MLST type isolated from two critical COVID-19 patients by combining sequencing analysis and phenotypic assays. Both P. aeruginosa strains were found to turn on alginate biosynthesis and attenuate type VI secretion system (T6SS) during short-term colonization in the COVID-19 patients, which results in excessive biofilm formation and virulence reduction-two distinct markers for chronic infections. The macrophage cytotoxicity test and intracellular reactive oxygen species measurement confirmed that the adapted P. aeruginosa strains reduced their virulence towards host cells and are better to escape from host immune clearance than their ancestors.

Conclusion

Our study suggests that SARS-CoV-2 infection can create a lung environment that allow rapid adaptive evolution of bacterial pathogens with genetic traits suitable for chronic infections.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00748-z.

Enhanced endocytosis elevated virulence and severity of SARS-CoV-2 due to hyperglycemia in type 2 diabetic patients

Diabetes mellitus is a metabolic disease that causes hyperglycemia. In COVID-19 patients the severity of the disease depends on myriad factors but diabetes mellitus is the most important comorbidity. The current review was conducted to investigate the virulence of SARS-CoV-2 and disease severity of COVID-19 in type 2 diabetes mellitus patients and relevant treatment. The literature published in PubMed, Scopus, Web of Science, and Google Scholar was reviewed up to September 2021. The keywords including SARS-CoV-2, type 2 diabetes mellitus in COVID-19, hyperglycemia in COVID-19, opportunistic infections in type 2 diabetes mellitus and COVID-19 were used in different combinations. Hyperglycemic individuals over-express ACE-2 receptors in the lungs thus increasing the SARS-CoV-2 susceptibility and replication. Although dipeptidyl peptidase-4 plays an important role in glucose homeostasis, additionally it also stimulates the production of proinflammatory cytokines such as IL-6 and TNF-α creating a cytokine storm. Cytokine storm might be responsible for respiratory insufficiency in severe COVID-19 patients. Type 2 diabetes mellitus is associated with immunosuppression and the patients are prone to get many opportunistic infections. Type 2 diabetes mellitus patients with severe COVID-19 have lymphopenia. Moreover, in type 2 diabetes mellitus patients the neutrophils exhibit decreased chemotaxis, hydrogen peroxide production, and phagocytosis. Reduction in lymphocyte count and defective neutrophil capacity renders them with COVID-19 susceptible to opportunistic bacterial and fungal infections increasing the mortality rate. The opportunistic bacterial infections in COVID-19 patients were due to Staphylococcus aureus, Streptococcus pneumonia, and coagulase-negative Staphylococci, E. coli, Pseudomonas aeruginosa, and Klebsiella sp. In COVID-19 patients with type 2 diabetes mellitus, mucormycosis was found to be the most common fungal infection with a higher predilection to males. Hyperglycemia in COVID-19 patients with type 2 diabetes mellitus enhances the SARS-CoV-2 replication with an adverse outcome. A strong correlation exists between the poor prognosis of COVID-19 and type 2 diabetes mellitus. Proper glycemic control in COVID-19 patients with diabetes mellitus might lessen the severity of the disease.

Coronavirus disease 2019 (COVID-19): Secondary bacterial infections and the impact on antimicrobial resistance during the COVID-19 pandemic

Secondary bacterial infections and bacterial coinfections are an important complication of coronavirus disease 2019 (COVID-19), leading to antibiotic overuse and increased rates of antimicrobial resistance (AMR) during the COVID-19 pandemic. In this literature review, we summarize the reported rates of secondary bacterial infections and bacterial coinfections in patients with COVID-19, the impact on patient outcomes, the antibiotic treatment approaches employed, and the resistance patterns observed. The reported data suggest that although the incidence of secondary bacterial infections or bacterial coinfections is relatively low, they are associated with worse outcomes such as prolonged hospitalization, intensive care unit admission, mechanical ventilator use, and increased mortality. Interestingly, antibiotic prescription rates are typically higher than secondary bacterial and bacterial coinfection rates, and reports of AMR are common. These findings highlight the need for an improved understanding of secondary bacterial and bacterial coinfection in patients with COVID-19, as well as improved treatment options, to mitigate inappropriate antibiotic prescribing and AMR.

Impact of Coinfection With SARS-CoV-2 and Influenza on Disease Severity: A Systematic Review and Meta-Analysis

Background: Although coinfection with influenza in COVID-19 patients has drawn considerable attention, it is still not completely understood whether simultaneously infected with these two viruses influences disease severity. We therefore aimed to estimate the impact of coinfected with SARS-CoV-2 and influenza on the disease outcomes compared with the single infection of SARS-CoV-2. Materials and Methods: We searched the PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure Database (CNKI) to identify relevant articles up to July 9, 2021. Studies that assessed the effect of SARS-CoV-2 and influenza coinfection on disease outcomes or those with sufficient data to calculate risk factors were included. Risk effects were pooled using fixed or random effects model. Results: We ultimately identified 12 studies with 9,498 patients to evaluate the risk effects of SARS-CoV-2 and influenza coinfection on disease severity. Results indicated that coinfection was not significantly associated with mortality (OR = 0.85, 95%CI: 0.51, 1.43; p = 0.55, I ² = 76.00%). However, mortality was found significantly decreased in the studies from China (OR = 0.51, 95%CI: 0.39, 0.68; I ² = 26.50%), while significantly increased outside China (OR = 1.56, 95%CI: 1.12, 2.19; I ² = 1.00%). Moreover, a lower risk for critical outcomes was detected among coinfection patients (OR = 0.64, 95%CI: 0.43, 0.97; p = 0.04, I ² = 0.00%). Additionally, coinfection patients presented different laboratory indexes compared with the single SARS-CoV-2 infection, including lymphocyte counts and APTT. Conclusion: Our study revealed that coinfection with SARS-CoV-2 and influenza had no effect on overall mortality. However, risk for critical outcomes was lower in coinfection patients and different associations were detected in the studies from different regions and specific laboratory indexes. Further studies on influenza strains and the order of infection were warranted. Systematic testing for influenza coinfection in COVID-19 patients and influenza vaccination should be recommended.

Bridging the Gaps between Plant and Human Health: A Systematic Review of Soyasaponins

Saponins, prominent secondary plant metabolites, are recognized for their roles in plant defense and medicinal benefits. Soyasaponins, commonly derived from legumes, are a class of triterpenoid saponins that demonstrate significant potential for plant and human health applications. Previous research and reviews largely emphasize human health effects of soyasaponins. However, the biological effects of soyasaponins and their implications for plants in the context of human health have not been well-discussed. This review provides comprehensive discussions on the biological roles of soyasaponins in plant defense and rhizosphere microbial interactions; biosynthetic regulation and compound production; immunological effects and potential for therapeutics; and soyasaponin acquisition attributed to processing effects, bioavailability, and biotransformation processes based on recent soyasaponin research. Given the multifaceted biological effects elicited by soyasaponins, further research warrants an integrated approach to understand molecular mechanisms of regulations in their production as well as their applications in plant and human health.

Clinical Evaluation of a Metagenomics-Based Assay for Pneumonia Management

Clinical value of metagenomic next-generation sequencing (mNGS) in pneumonia management is still controversial. A prospective study was conducted to evaluate the clinical impact of PneumoSeq in 57 immunocompetent (ICO) and 75 immunocompromised (ICH) pneumonia patients. The value of PneumoSeq for both etiological and clinical impact investigation in pneumonia was assessed. Among the 276 potential pathogens detected with PneumoSeq in our cohort, 251 (90.9%) were cross-validated. Clinical diagnoses of the causative pathogens were obtained for 97 patients, 90.7% of which were supported by PneumoSeq. Compared to conventional testing, PneumoSeq suggested potentially missed diagnoses in 16.7% of cases (22/132), involving 48 additional pathogenic microorganisms. In 58 (43.9%) cases, PneumoSeq data led to antimicrobial treatment de-escalation (n = 12 in ICO, n = 18 in ICH) and targeted treatment initiation (n = 7 in ICO, n = 21 in ICH). The PneumoSeq assay benefited the diagnosis and clinical management of both ICH and ICO pneumonia patients in real-world settings.

Bloodstream Infections in Hospitalized Patients with COVID-19: A Systematic Review and Meta-Analysis

Background: Little is known about the occurrence of bloodstream infections in hospitalized patients with COVID-19 and the related clinical consequences. The aim of this systematic review and meta-analysis was to estimate the pooled occurrence of BSIs among hospitalized patients with COVID-19 and mortality of this patient population. Methods: A systematic search was performed on PubMed, EMBASE, and Web of Science from inception to 19 April 2021. The primary outcome was the occurrence of BSIs among hospitalized patients with COVID-19. The secondary outcome was mortality at the longest available follow-up. Results: Forty-six studies met the inclusion criteria, with a total of 42,694 patients evaluated. The estimated occurrence of BSIs was 7.3% (95% CI 4.7–1.1%) among hospitalized patients with COVID-19, with a mortality rate of 41% (95% CI 30%–52.8%). The subgroup analysis conducted on patients admitted to ICU provided an estimated occurrence of 29.6% (95% CI 21.7%–38.8%). A higher occurrence of BSI was observed in patients with COVID-19, in comparison with patients without COVID-19 (OR 2.77; 95% CI 1.53–5.02; p < 0.001). Conclusions: Our analysis estimated the occurrence of BSIs among hospitalized patients with COVID-19 at around 7%. A four-times higher occurrence was estimated among patients admitted to ICU.

High-value laboratory testing for hospitalized COVID-19 patients: a review

We present here an evidence-based review of the utility, timing, and indications for laboratory test use in the domains of inflammation, cardiology, hematology, nephrology and co-infection for clinicians managing the care of hospitalized COVID-19 patients. Levels of IL-6, CRP, absolute lymphocyte count, neutrophils and neutrophil-to-lymphocyte ratio obtained upon admission may help predict the severity of COVID-19. Elevated LDH, ferritin, AST, and d-dimer are associated with severe illness and mortality. Elevated cardiac troponin at hospital admission can alert clinicians to patients at risk for cardiac complications. Elevated proBNP may help distinguish a cardiac complication from noncardiac etiologies. Evaluation for co-infection is typically unnecessary in nonsevere cases but is essential in severe COVID-19, intensive care unit patients, and immunocompromised patients.

Rapid Genomic Diagnosis of Fungal Infections in the Age of Next-Generation Sequencing

Next-generation sequencing (NGS) technologies have recently developed beyond the research realm and started to mature into clinical applications. Here, we review the current use of NGS for laboratory diagnosis of fungal infections. Since the first reported case in 2014, >300 cases of fungal infections diagnosed by NGS were described. Pneumocystis jirovecii is the predominant fungus reported, constituting ~25% of the fungi detected. In ~12.5% of the cases, more than one fungus was detected by NGS. For P. jirovecii infections diagnosed by NGS, all 91 patients suffered from pneumonia and only 1 was HIV-positive. This is very different from the general epidemiology of P. jirovecii infections, of which HIV infection is the most important risk factor. The epidemiology of Talaromyces marneffei infection diagnosed by NGS is also different from its general epidemiology, in that only 3/11 patients were HIV-positive. The major advantage of using NGS for laboratory diagnosis is that it can pick up all pathogens, particularly when initial microbiological investigations are unfruitful. When the cost of NGS is further reduced, expertise more widely available and other obstacles overcome, NGS would be a useful tool for laboratory diagnosis of fungal infections, particularly for difficult-to-grow fungi and cases with low fungal loads.