Staphylococcus aureus Lipase 1 Enhances Influenza A Virus Replication

A review of the influence of environmental pollutants (microplastics, pesticides, antibiotics, air pollutants, viruses, bacteria) on animal viruses

Microorganisms, especially viruses, cause disease in both humans and animals. Environmental chemical pollutants including microplastics, pesticides, antibiotics sand air pollutants arisen from human activities affect both animal and human health. This review assesses the impact of chemical and biological contaminants (virus and bacteria) on viruses including its life cycle, survival, mutations, loads and titers, shedding, transmission, infection, re-assortment, interference, abundance, viral transfer between cells, and the susceptibility of the host to viruses. It summarizes the sources of environmental contaminants, interactions between contaminants and viruses, and methods used to mitigate such interactions. Overall, this review provides a perspective of environmentally co-occurring contaminants on animal viruses that would be useful for future research on virus-animal-human-ecosystem harmony studies to safeguard human and animal health.

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.

Viral-Bacterial Interactions That Impact Viral Thermostability and Transmission

Enteric viruses are significant human pathogens that commonly cause foodborne illnesses worldwide. These viruses initiate infection in the gastrointestinal tract, home to a diverse population of intestinal bacteria. In a novel paradigm, data indicate that enteric viruses utilize intestinal bacteria to promote viral replication and pathogenesis. While mechanisms underlying these observations are not fully understood, data suggest that some enteric viruses bind directly to bacteria, stabilizing the virion to retain infectivity. Here, we discuss the current knowledge of these viral-bacterial interactions and examine the impact of these interactions on viral transmission.

GehB Inactivates Lipoproteins to Delay the Healing of Acute Wounds Infected with Staphylococcus aureus

Staphylococcus aureus is one of the most prevalent bacteria found in acute wounds. S. aureus produces many virulence factors and extracellular enzymes that contribute to bacterial survival, dissemination, and pathogenicity. Lipase GehB is a glycerol ester hydrolase that hydrolyzes triglycerides to facilitate the evasion of S. aureus from host immune recognition. However, the role and mechanism of lipase GehB in skin acute wound healing after S. aureus infection remain unclear. In this study, we found that the gehB gene deletion mutant (USA300ΔgehB) stimulated significantly higher levels of pro-inflammatory cytokines in RAW264.7 and Toll-like receptor 2 (TLR2)-transfected HEK293 cells than the wild-type USA300 strain did. Recombinant GehB-His treated lipoprotein (Lpp) reduced stimulation of TLR2-dependent TNF-α production by RAW264.7 macrophages. GehB delayed the skin acute wound healing in BALB/c mice infected with S. aureus, while wound healing was similar in C57BL/6 TLR2-/- mice infected with either wild-type USA300 or USA300ΔgehB. In BALB/c mice, we also observed more bacterial survival, less leukocyte recruitment, lower IL-8 production, and adipocyte differentiation in USA300-infected skin acute wound tissues than those in USA300ΔgehB-challenged ones. Our data indicated that GehB inactivates lipoproteins to shield S. aureus from innate immune killing, resulting in delayed the healing of skin acute wounds infected with S. aureus.

Altered Respiratory Microbiomes, Plasma Metabolites, and Immune Responses in Influenza A Virus and Methicillin-Resistant Staphylococcus aureus Coinfection

Influenza A virus (IAV)-methicillin-resistant Staphylococcus aureus (MRSA) coinfection causes severe respiratory infections. The host microbiome plays an important role in respiratory tract infections. However, the relationships among the immune responses, metabolic characteristics, and respiratory microbial characteristics of IAV-MRSA coinfection have not been fully studied. We used specific-pathogen-free (SPF) C57BL/6N mice infected with IAV and MRSA to build a nonlethal model of IAV-MRSA coinfection and characterized the upper respiratory tract (URT) and lower respiratory tract (LRT) microbiomes at 4 and 13 days postinfection by full-length 16S rRNA gene sequencing. Immune response and plasma metabolism profile analyses were performed at 4 days postinfection by flow cytometry and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The relationships among the LRT microbiota, the immune response, and the plasma metabolism profile were analyzed by Spearman's correlation analysis. IAV-MRSA coinfection showed significant weight loss and lung injury and significantly increased loads of IAV and MRSA in bronchoalveolar lavage fluid (BALF). Microbiome data showed that coinfection significantly increased the relative abundances of Enterococcus faecalis, Enterobacter hormaechei, Citrobacter freundii, and Klebsiella pneumoniae and decreased the relative abundances of Lactobacillus reuteri and Lactobacillus murinus. The percentages of CD4+/CD8+ T cells and B cells in the spleen; the levels of interleukin-9 (IL-9), interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), IL-6, and IL-8 in the lung; and the level of mevalonolactone in plasma were increased in IAV-MRSA-coinfected mice. L. murinus was positively correlated with lung macrophages and natural killer (NK) cells, negatively correlated with spleen B cells and CD4+/CD8+ T cells, and correlated with multiple plasma metabolites. Future research is needed to clarify whether L. murinus mediates or alters the severity of IAV-MRSA coinfection. IMPORTANCE The respiratory microbiome plays an important role in respiratory tract infections. In this study, we characterized the URT and LRT microbiota, the host immune response, and plasma metabolic profiles during IAV-MRSA coinfection and evaluated their correlations. We observed that IAV-MRSA coinfection induced severe lung injury and dysregulated host immunity and plasma metabolic profiles, as evidenced by the aggravation of lung pathological damage, the reduction of innate immune cells, the strong adaptation of the immune response, and the upregulation of mevalonolactone in plasma. L. murinus was strongly correlated with immune cells and plasma metabolites. Our findings contribute to a better understanding of the role of the host microbiome in respiratory tract infections and identified a key bacterial species, L. murinus, that may provide important references for the development of probiotic therapies.

Airborne fine particles drive H1N1 viruses deep into the lower respiratory tract and distant organs

Mounting data suggest that environmental pollution due to airborne fine particles (AFPs) increases the occurrence and severity of respiratory virus infection in humans. However, it is unclear whether and how interactions with AFPs alter viral infection and distribution. We report synergetic effects between various AFPs and the H1N1 virus, regulated by physicochemical properties of the AFPs. Unlike infection caused by virus alone, AFPs facilitated the internalization of virus through a receptor-independent pathway. Moreover, AFPs promoted the budding and dispersal of progeny virions, likely mediated by lipid rafts in the host plasma membrane. Infected animal models demonstrated that AFPs favored penetration of the H1N1 virus into the distal lung, and its translocation into extrapulmonary organs including the liver, spleen, and kidney, thus causing severe local and systemic disorders. Our findings revealed a key role of AFPs in driving viral infection throughout the respiratory tract and beyond. These insights entail stronger air quality management and air pollution reduction policies.

The Staphylococcus aureus protein IsdA increases SARS CoV-2 replication by modulating JAK-STAT signaling

The Severe Acute Respiratory Syndrome Coronavirus 2 (CoV-2) pandemic has affected millions globally. A significant complication of CoV-2 infection is secondary bacterial co-infection, as seen in approximately 25% of severe cases. The most common organism isolated during co-infection is Staphylococcus aureus. Here, we describe the development of an in vitro co-infection model where both viral and bacterial replication kinetics may be examined. We demonstrate CoV-2 infection does not alter bacterial interactions with host epithelial cells. In contrast, S. aureus enhances CoV-2 replication by 10- to 15-fold. We identify this pro-viral activity is due to the S. aureus iron-regulated surface determinant A (IsdA) protein and demonstrate IsdA modifies host transcription. We find that IsdA alters Janus Kinase - Signal Transducer and Activator of Transcription (JAK-STAT) signaling, by affecting JAK2-STAT3 levels, ultimately leading to increased viral replication. These findings provide key insight into the molecular interactions between host cells, CoV-2 and S. aureus during co-infection.

Essential Fitness Repertoire of Staphylococcus aureus during Co-infection with Acinetobacter baumannii In Vivo

Staphylococcus aureus represents a major human pathogen that is frequently involved in polymicrobial infections. However, the prevalence and role of co-infectious microbes on the pathogenesis and fitness essentiality of S. aureus in vivo remain largely unknown. In this study, we firstly performed a retrospective surveillance of 760 clinical samples and revealed a notable predominance of co-infection with S. aureus and Acinetobacter baumannii. The high-density S. aureus transposon mutant library coupled to transposon insertion sequencing (Tn-Seq) further identified a core set of genes enriched in metabolism of inorganic ions, amino acids, and carbohydrates, which are essential for infection and tissue colonization of S. aureus in the murine systemic infection model. Notably, we revealed a differential requirement of fitness factors for S. aureus in tissue-specific (liver and kidney) and infection-type-specific manner (mono- and co-infection). Co-infection with A. baumannii dramatically altered the fitness requirements of S. aureus in vivo; 49% of the mono-infection fitness genes in S. aureus strain Newman were converted to non-essential, and the functionality of ATP-binding cassette (ABC) transporters was significantly elicited during co-infection. Furthermore, the number of genes essential during co-infection (503) outnumbers the genes essential during mono-infection (362). In addition, the roles of 3 infection-type-specific genes in S. aureus during mono-infection or co-infection with A. baumannii were validated with competitive experiments in vivo. Our data indicated a high incidence and clinical relevance of S. aureus and A. baumannii co-infection, and provided novel insights into establishing antimicrobial regimens to control co-infections. IMPORTANCE Polymicrobial infections are widespread in clinical settings, which potentially correlate with increased infection severity and poor clinical outcomes. Staphylococcus aureus is a formidable human pathogen that causes a variety of diseases in polymicrobial nature. Co-infection and interaction of S. aureus have been described with limited pathogens, mainly including Pseudomonas aeruginosa, Candida albicans, and influenza A virus. Thus far, the prevalence and role of co-infectious microbes on the pathogenesis and fitness essentiality of S. aureus in vivo remain largely unknown. Understanding the polymicrobial composition and interaction, from a community and genome-wide perspective, is thus crucial to shed light on S. aureus pathogenesis strategy. Here, our findings demonstrated, for the first time, that a high incidence rate and clinical relevance of co-infection was caused by S. aureus and Acinetobacter baumannii, illustrating the importance of polymicrobial nature in investigating S. aureus pathogenesis. The infection-type-specific genes likely serve as potential therapeutic targets to control S. aureus infections, either in mono- or co-infection situation, providing novel insights into the development of antimicrobial regimens to control co-infections.

The Emergence of a Multidrug-Resistant and Pathogenic ST42 Lineage of Staphylococcus haemolyticus from a Hospital in China

Staphylococcus haemolyticus is an opportunistic pathogen associated with hospital-acquired infections. However, the genetic diversity of S. haemolyticus among the patients and the hospital environment is largely unknown. Here, we isolated 311 S. haemolyticus strains from different sampling sites of patients and hospital environment. Genomic analysis showed that ST42 is an emerging clone widely disseminated in the hospital. S. haemolyticus ST42 strains exhibited decreased susceptibilities for multiple antibiotics compared with other STs and carried significantly more antibiotic resistance genes (ARGs). Furthermore, ST42 strains harbored more virulence genes per isolate than in other STs, and the capsular biosynthesis genes capDEFG were more prevalent in ST42 strains. Using the Galleria mellonella infection model, we demonstrated that ST42 strains are highly virulent compared with non-ST42 strains. Taken together, our data identified an emerging ST42 clone of S. haemolyticus with aggregated ARGs and virulence determinants in the hospital, representing a significant health threat in terms of both disease and treatment. IMPORTANCES. haemolyticus is an emerging opportunistic pathogen with a high burden of antimicrobial resistance. We performed molecular epidemiological analysis of S. haemolyticus that was isolated from a hospital, and found that the phylogenetic lineages are diverse accompanied by a dominant epidemic clonal lineage ST42. We demonstrated that S. haemolyticus ST42 strains have been disseminated among patients and the hospital environment. The data provide mechanistic insight and indicate that S. haemolyticus ST42 strains are multidrug-resistance and virulent clones via accumulating more ARGs and virulence genes.

Identification and Application of a Panel of Constitutive Promoters for Gene Overexpression in Staphylococcus aureus

Staphylococcus aureus is a leading pathogen that is currently the most common cause of infection in hospitalized patients. An in-depth genetic analysis of S. aureus virulence genes contributing to pathogenesis is needed to develop novel antimicrobial therapies. However, tools for genetic manipulation in S. aureus are limited, particularly those for gene expression. Here, 38 highly expressed genes were identified in S. aureus USA300_FPR3757 via RNA-seq. Promoter regions from 30 of these genes were successfully cloned, of which 20 promoters exhibited a wide range of activity. By utilizing these active promoters, 20 S. aureus-Escherichia coli shuttle vectors were constructed and evaluated by expressing an egfp reporter gene. Expression of the egfp gene under the control of different promoters was confirmed and quantified by Western blotting and qPCR, which suggested that the activity of these promoters varied from 18 to 650% of the activity of P_sarA, a widely used promoter for gene expression. In addition, our constructed vectors were verified to be highly compatible with gene expression in different S. aureus strains. Furthermore, these vectors were evaluated and used to overexpress two endogenous proteins in S. aureus, namely, catalase and the transcriptional repressor of purine biosynthesis (PurR). Meanwhile, the physiological functions and phenotypes of overexpressed PurR and catalase in S. aureus were validated. Altogether, this evidence indicates that our constructed vectors provide a wide range of promoter activity on gene expression in S. aureus. This set of vectors carrying different constitutive promoters developed here will provide a powerful tool for the direct analysis of target gene function in staphylococcal cells.

Staphylococcus aureus Lipase 3 (SAL3) is a surface-associated lipase that hydrolyzes short chain fatty acids

Bacterial lipases play important roles during infection. The Staphylococcus aureus genome contains several genes that encode well-characterized lipases and several genes predicted to encode lipases or esterases for which the function has not yet been established. In this study, we sought to define the function of an uncharacterized S. aureus protein, and we propose the annotation S. aureus lipase 3 (SAL3) (SAUSA300_0641). We confirmed that SAL3 is a lipase and that it is surface associated and secreted through an unknown mechanism. We determined that SAL3 specifically hydrolyzes short chain (4-carbon and fewer) fatty acids and specifically binds negatively charged lipids including phosphatidic acid, phosphatidylinositol phosphate, and phosphatidylglycerol, which is the most abundant lipid in the staphylococcal cell membrane. Mutating the catalytic triad S66-A, D167-A, S168-A, and H301-A in the recombinant protein abolished lipase activity without altering binding to host lipid substrates. Taken together we report the discovery of a novel lipase from S. aureus specific to short chain fatty acids with yet to be determined roles in host pathogen interactions.

Diagnosing hospital bacteraemia in the framework of predictive, preventive and personalised medicine using electronic health records and machine learning classifiers

Background

The bacteraemia prediction is relevant because sepsis is one of the most important causes of morbidity and mortality. Bacteraemia prognosis primarily depends on a rapid diagnosis. The bacteraemia prediction would shorten up to 6 days the diagnosis, and, in conjunction with individual patient variables, should be considered to start the early administration of personalised antibiotic treatment and medical services, the election of specific diagnostic techniques and the determination of additional treatments, such as surgery, that would prevent subsequent complications. Machine learning techniques could help physicians make these informed decisions by predicting bacteraemia using the data already available in electronic hospital records.

Objective

This study presents the application of machine learning techniques to these records to predict the blood culture's outcome, which would reduce the lag in starting a personalised antibiotic treatment and the medical costs associated with erroneous treatments due to conservative assumptions about blood culture outcomes.

Methods

Six supervised classifiers were created using three machine learning techniques, Support Vector Machine, Random Forest and K-Nearest Neighbours, on the electronic health records of hospital patients. The best approach to handle missing data was chosen and, for each machine learning technique, two classification models were created: the first uses the features known at the time of blood extraction, whereas the second uses four extra features revealed during the blood culture.

Results

The six classifiers were trained and tested using a dataset of 4357 patients with 117 features per patient. The models obtain predictions that, for the best case, are up to a state-of-the-art accuracy of 85.9%, a sensitivity of 87.4% and an AUC of 0.93.

Conclusions

Our results provide cutting-edge metrics of interest in predictive medical models with values that exceed the medical practice threshold and previous results in the literature using classical modelling techniques in specific types of bacteraemia. Additionally, the consistency of results is reasserted because the three classifiers' importance ranking shows similar features that coincide with those that physicians use in their manual heuristics. Therefore, the efficacy of these machine learning techniques confirms their viability to assist in the aims of predictive and personalised medicine once the disease presents bacteraemia-compatible symptoms and to assist in improving the healthcare economy.

Outcomes of respiratory viral-bacterial co-infection in adult hospitalized patients

BACKGROUND

Viral infections of the respiratory tract represent a major global health concern. Co-infection with bacteria may contribute to severe disease and increased mortality in patients. Nevertheless, viral-bacterial co-infection patterns and their clinical outcomes have not been well characterized to date. This study aimed to evaluate the clinical features and outcomes of patients with viral-bacterial respiratory tract co-infections.

METHODS

We included 19,361 patients with respiratory infection due to respiratory viruses [influenza A and B, respiratory syncytial virus (RSV), parainfluenza] and/or bacteria in four tertiary hospitals in Hong Kong from 2013 to 2017 using a large territory-wide healthcare database. All microbiological tests were conducted within 48 h of hospital admission. Four etiological groups were included: (1) viral infection alone; (2) bacterial infection alone; (3) laboratory-confirmed viral-bacterial co-infection and (4) clinically suspected viral-bacterial co-infection who were tested positive for respiratory virus and negative for bacteria but had received at least four days of antibiotics. Clinical features and outcomes were recorded for laboratory-confirmed viral-bacterial co-infection patients compared to other three groups as control. The primary outcome was 30-day mortality. Secondary outcomes were intensive care unit (ICU) admission and length of hospital stay. Propensity score matching estimated by binary logistic regression was used to adjust for the potential bias that may affect the association between outcomes and covariates.

FINDINGS

Among 15,906 patients with respiratory viral infection, there were 8451 (53.1%) clinically suspected and 1,087 (6.8%) laboratory-confirmed viral-bacterial co-infection. Among all the bacterial species, Haemophilus influenzae (226/1,087, 20.8%), Pseudomonas aeruginosa (180/1087, 16.6%) and Streptococcus pneumoniae (123/1087, 11.3%) were the three most common bacterial pathogens in the laboratory-confirmed co-infection group. Respiratory viruses co-infected with non-pneumococcal streptococci or methicillin-resistant Staphylococcus aureus was associated with the highest death rate [9/30 (30%) and 13/48 (27.1%), respectively] in this cohort. Compared with other infection groups, patients with laboratory-confirmed co-infection had higher ICU admission rate (p < 0.001) and mortality rate at 30 days (p = 0.028), and these results persisted after adjustment for potential confounders using propensity score matching. Furthermore, patients with laboratory-confirmed co-infection had significantly higher mortality compared to patients with bacterial infection alone.

INTERPRETATION

In our cohort, bacterial co-infection is common in hospitalized patients with viral respiratory tract infection and is associated with higher ICU admission rate and mortality. Therefore, active surveillance for bacterial co-infection and early antibiotic treatment may be required to improve outcomes in patients with respiratory viral infection.

Staphylococcus aureus secreted lipases do not inhibit innate immune killing mechanisms

Background:Staphylococcus aureus causes an array of diseases in both humans and livestock. Pathogenesis is mediated by a plethora of proteins secreted by S. aureus, many of which remain incompletely characterised. For example, S. aureus abundantly secretes two isoforms of the enzyme lipase into the extracellular milieu, where they scavenge upon polymeric triglycerides. It has previously been suggested that lipases may interfere with the function of innate immune cells, such as macrophages and neutrophils, but the impact of lipases on phagocytic killing mechanisms remains unknown.

Methods: We employed the epidemic S. aureus clone USA300 strain LAC and its lipase deficient isogenic mutant, along with recombinant lipase proteins, in in vitro experimental infection assays. To determine if lipases can inhibit innate immune killing mechanisms, the bactericidal activity of whole blood, human neutrophils, and macrophages was analysed. In addition, gentamycin protection assays were carried out to examine the influence of lipases on S. aureus innate immune cell escape.

Results: There were no differences in the survival of S. aureus USA300 LAC wild type and its lipase-deficient isogenic mutant after incubation with human whole blood or neutrophils. Furthermore, there was no detectable lipase-dependent effect on phagocytosis, intracellular survival, or escape from both human primary and immortalised cell line macrophages, even upon supplementation with exogenous recombinant lipases.

Conclusions: S. aureus lipases do not inhibit bacterial killing mechanisms of human macrophages, neutrophils, or whole blood. These findings broaden our understanding of the interaction of S. aureus with the innate immune system.

Staphylococcus aureus secreted lipases do not inhibit innate immune killing mechanisms

Background: Staphylococcus aureus causes an array of diseases in both humans and livestock. Pathogenesis is mediated by a plethora of proteins secreted by S. aureus, many of which remain incompletely characterised. For example, S. aureus abundantly secretes two isoforms of the enzyme lipase into the extracellular milieu, where they scavenge upon polymeric triglycerides. It has previously been suggested that lipases may interfere with the function of innate immune cells, such as macrophages and neutrophils, but the impact of lipases on phagocytic killing mechanisms remains unknown. Methods: We employed the epidemic S. aureus clone USA300 strain LAC and its lipase deficient isogenic mutant, along with recombinant lipase proteins, in in vitro experimental infection assays. To determine if lipases can inhibit innate immune killing mechanisms, the bactericidal activity of whole blood, human neutrophils, and macrophages was analysed. In addition, gentamycin protection assays were carried out to examine the influence of lipases on S. aureus innate immune cell escape. Results: There were no differences in the survival of S. aureus USA300 LAC wild type and its lipase-deficient isogenic mutant after incubation with human whole blood or neutrophils. Furthermore, there was no detectable lipase-dependent effect on phagocytosis, intracellular survival, or escape from both human primary and immortalised cell line macrophages, even upon supplementation with exogenous recombinant lipases. Conclusions: S. aureus lipases do not inhibit bacterial killing mechanisms of human macrophages, neutrophils, or whole blood. These findings broaden our understanding of the interaction of S. aureus with the innate immune system.

Staphylococcus aureus Bacteremia in Patients Infected With COVID-19: A Case Series

Background

Previous viral pandemics have shown that secondary bacterial infections result in higher morbidity and mortality, with Staphylococcus aureus being the primary causative pathogen. The impact of secondary S. aureus bacteremia on mortality in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unknown.

Methods

This was a retrospective observational case series of patients with coronavirus disease 2019 (COVID-19) who developed secondary S. aureus bacteremia across 2 New York City hospitals. The primary end point was to describe 14-day and 30-day hospital mortality rates of patients with COVID-19 and S. aureus bacteremia. Secondary end points included predictors of 14-day and 30-day hospital mortality in patients with COVID-19 and S. aureus bacteremia.

Results

A total of 42 patients hospitalized for COVID-19 with secondary S. aureus bacteremia were identified. Of these patients, 23 (54.8%) and 28 (66.7%) died at 14 days and 30 days, respectively, from their first positive blood culture. Multivariate analysis identified hospital-onset bacteremia (≥4 days from date of admission) and age as significant predictors of 14-day hospital mortality and Pitt bacteremia score as a significant predictor of 30-day hospital mortality (odds ratio [OR], 11.9; 95% CI, 2.03-114.7; P = .01; OR, 1.10; 95% CI, 1.03-1.20; P = .02; and OR, 1.56; 95% CI, 1.19-2.18; P = .003, respectively).

Conclusions

Bacteremia with S. aureus is associated with high mortality rates in patients hospitalized with COVID-19. Further investigation is warranted to understand the impact of COVID-19 and secondary S. aureus bacteremia.