Pseudomonas aeruginosa Lipoxygenase LoxA Contributes to Lung Infection by Altering the Host Immune Lipid Signaling

Pseudomonas aeruginosa: metabolic allies and adversaries in the world of polymicrobial infections

Pseudomonas aeruginosa (PA), an opportunistic human pathogen that is frequently linked with chronic infections in immunocompromised individuals, is also metabolically versatile, and thrives in diverse environments. Additionally, studies report that PA can interact with other microorganisms, such as bacteria, and fungi, producing unique metabolites that can modulate the host immune response, and contribute to disease pathogenesis. This review summarizes the current knowledge related to the metabolic interactions of PA with other microorganisms (Staphylococcus, Acinetobacter, Klebsiella, Enterococcus, and Candida) and human hosts, and the importance of these interactions in a polymicrobial context. Further, we highlight the potential applications of studying these metabolic interactions toward designing better diagnostic tools, and therapeutic strategies to prevent, and treat infections caused by this pathogen.

Modeling Host-Pathogen Interactions in C. elegans: Lessons Learned from Pseudomonas aeruginosa Infection

Infections, such as that by the multiresistant opportunistic bacterial pathogen Pseudomonas aeruginosa, may pose a serious health risk, especially on vulnerable patient populations. The nematode Caenorhabditis elegans provides a simple organismal model to investigate both pathogenic mechanisms and the emerging role of innate immunity in host protection. Here, we review the virulence and infection strategies of P. aeruginosa and host defenses of C. elegans. We summarize the recognition mechanisms of patterns of pathogenesis, including novel pathogen-associated molecular patterns and surveillance immunity of translation, mitochondria, and lysosome-related organelles. We also review the regulation of antimicrobial and behavioral defenses by the worm's neuroendocrine system. We focus on how discoveries in this rich field align with well-characterized evolutionary conserved protective pathways, as well as on potential crossovers to human pathogenesis and innate immune responses.

Lipoxygenases at the Intersection of Infection and Carcinogenesis

The persisting presence of opportunistic pathogens like Pseudomonas aeruginosa poses a significant threat to many immunocompromised cancer patients with pulmonary infections. This review highlights the complexity of interactions in the host's defensive eicosanoid signaling network and its hijacking by pathogenic bacteria to their own advantage. Human lipoxygenases (ALOXs) and their mouse counterparts are integral elements of the innate immune system, mostly operating in the pro-inflammatory mode. Taking into account the indispensable role of inflammation in carcinogenesis, lipoxygenases have counteracting roles in this process. In addition to describing the structure-function of lipoxygenases in this review, we discuss their roles in such critical processes as cancer cell signaling, metastases, death of cancer and immune cells through ferroptosis, as well as the roles of ALOXs in carcinogenesis promoted by pathogenic infections. Finally, we discuss perspectives of novel oncotherapeutic approaches to harness lipoxygenase signaling in tumors.

Pseudomonas aeruginosa: Infections and novel approaches to treatment "Knowing the enemy" the threat of Pseudomonas aeruginosa and exploring novel approaches to treatment

Pseudomonas aeruginosa is an aerobic Gram-negative rod-shaped bacterium with a comparatively large genome and an impressive genetic capability allowing it to grow in a variety of environments and tolerate a wide range of physical conditions. This biological flexibility enables the P. aeruginosa to cause a broad range of infections in patients with serious underlying medical conditions, and to be a principal cause of health care associated infection worldwide. The clinical manifestations of P. aeruginosa include mostly health care associated infections and community-acquired infections. P. aeruginosa possesses an array of virulence factors that counteract host defence mechanisms. It can directly damage host tissue while utilizing high levels of intrinsic and acquired antimicrobial resistance mechanisms to counter most classes of antibiotics. P. aeruginosa co-regulates multiple resistance mechanisms by perpetually moving targets poses a significant therapeutic challenge. Thus, there is an urgent need for novel approaches in the development of anti-Pseudomonas agents. Here we review the principal infections caused by P. aeruginosa and we discuss novel therapeutic options to tackle antibiotic resistance and treatment of P. aeruginosa infections that may be further developed for clinical practice.

Lipoxygenase in a Giant Sulfur Bacterium: An Evolutionary Solution for Size and Complexity?

Discovery of Thiomargarita magnifica - an exceptionally large giant sulfur bacterium - urges us to pay additional attention to the giant sulfur bacteria and to revisit our recent bioinformatic finding of lipoxygenases in the representatives of the genus Beggiatoa. These close relatives of Thiomargarita magnifica meet the similar size requirements by forming multicellular structures. We hypothesize that their lipoxygenases are a part of the oxylipin signaling system that provides high level of cell-to-cell signaling complexity which, in turn, enables them to reach large sizes.

Host cell responses against the pseudomonal biofilm: A continued tale of host-pathogen interactions

In biofilm formation, pathogens within the bacterial community coordinate a cell-cell communication system called quorum sensing (QS). This is achieved through various signalling pathways that regulate bacterial virulence and host immune response. Here, we reviewed the host responses, key clinical implications, and novel therapeutic approaches against the biofilms of P. aeruginosa. Given the high degree of intrinsic antibiotic resistance and biofilm formation by the pathogen, the ensuing treatment complications could result in high morbidity and mortality rates worldwide. Notwithstanding the availability of intervention strategies, there remains a paucity of effective therapeutic options to control biofilmogenesis. This review discusses the basic understanding of QS-associated virulence factors and several key therapeutic interventions to foil the biofilm menace of P. aeruginosa.

Simultaneous profiling and quantification of 25 eicosanoids in human serum by ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry

The eicosanoid metabolic pathway is responsible for mediating the production of various inflammatory factors that are closely related to the development and resolution of inflammation. In biological matrices, the major quantifying obstacles were shown to be the oxidation and low quantities of eicosanoids and their metabolites. This study aimed to develop a reliable, sensitive ultrahigh-performance liquid chromatography coupled to a tandem mass spectrometry (UPLC–MS/MS) method to quantify eicosanoids in human serum. Solid-phase extraction (SPE) was used for sample preparation. The approach employed continuous ionization polarity switching. The target eicosanoids showed good linearity over the investigated concentration range (r2 > 0.99). The recovery rates were over 64.5%, and the matrix effects ranged from 73.0 to 128.0%. The limits of quantification were 0.048 ~ 0.44 ng/mL. For the broad concentration range, the CV % for accuracy and precision were less than ± 20%. We successfully applied this method to rapidly analyse 74 serum samples from severe influenza pneumonia, severe bacterial pneumonia and healthy individuals. Eicosanoid-related metabolite concentrations were quantified within a range similar to those of previously published articles. Compared to healthy individuals, our application found that 20-HETE, 14,15-EET and 11,12-EET were upregulated in severe influenza pneumonia patients, while LTB4 was downregulated. 8-HETE and 5-HETE were upregulated in severe bacterial pneumonia patients, while LTE4 was downregulated. This approach provides a means for monitoring the low quantities of eicosanoids in biological matrices, and our finding that different characteristic metabolite profiles may help discriminate the induction of severe pneumonia patients.

NLRP3 inflammasome activation in cigarette smoke priming for Pseudomonas aeruginosa-induced acute lung injury

It is increasingly recognized that cigarette smoke (CS) exposure increases the incidence and severity of acute respiratory distress syndrome (ARDS) in critical ill humans and animals. However, the mechanism(s) is not well understood. This study aims to investigate mechanism underlying the priming effect of CS on Pseudomonas aeruginosa-triggered acute lung injury, by using pre-clinic animal models and genetically modified mice. We demonstrated that CS impaired P. aeruginosa-induced mitophagy flux, promoted p62 accumulation, and exacerbated P. aeruginosa-triggered mitochondrial damage and NLRP3 inflammasome activation in alveolar macrophages; an effect associated with increased acute lung injury and mortality. Pharmacological inhibition of caspase-1, a component of inflammasome, attenuated CS primed P. aeruginosa-triggered acute lung injury and improved animal survival. Global or myeloid-specific knockout of IL-1β, a downstream component of inflammasome activation, also attenuated CS primed P. aeruginosa-triggered acute lung injury. Our results suggest that NLRP3 inflammasome activation is an important mechanism for CS primed P. aeruginosa-triggered acute lung injury. (total words: 155).

Fungal and bacterial oxylipins are signals for intra- and inter-cellular communication within plant disease

Lipids are central at various stages of host-pathogen interactions in determining virulence and modulating plant defense. Free fatty acids may act as substrates for oxidizing enzymes [e.g., lipoxygenases (LOXs) and dioxygenases (DOXs)] that synthesize oxylipins. Fatty acids and oxylipins function as modulators of several pathways in cell-to-cell communication; their structural similarity among plant, fungal, and bacterial taxa suggests potential in cross-kingdom communication. We provide a prospect of the known role of fatty acids and oxylipins in fungi and bacteria during plant-pathogen interactions. In the pathogens, oxylipin-mediated signaling pathways are crucial both in development and host infection. Here, we report on case studies suggesting that oxylipins derived from oleic, linoleic, and linolenic acids are crucial in modulating the pathogenic lifestyle in the host plant. Intriguingly, overlapping (fungi-plant/bacteria-plant) results suggest that different inter-kingdom pathosystems use similar lipid signals to reshape the lifestyle of the contenders and occasionally determine the outcome of the challenge.

A newly synthesized 17-epi-NeuroProtectin D1/17-epi-Protectin D1: Authentication and functional regulation of Inflammation-Resolution

The production of specialized pro-resolving mediators (SPMs) during the resolution phase in the inflammatory milieu is key to orchestrating the resolution of the acute inflammatory response. 17-epi-neuroprotectin D1/17-epi-protectin D1 (17-epi-NPD1/17-epi-PD1: 10R,17R-dihydroxy-4Z,7Z,11E,13E,15Z,19Z-docosahexaenoic acid) is an SPM of the protectin family, biosynthesized from docosahexaenoic acid (DHA), that exhibits both potent anti-inflammatory and neuroprotective functions. Here, we carried out a new commercial-scale synthesis of 17-epi-NPD1/17-epi-PD1 that enabled the authentication and confirmation of its potent bioactions in vivo and determination of its ability to activate human leukocyte phagocytosis. We provide evidence that this new synthetic 17-epi-NPD1/17-epi-PD1 statistically significantly increases human macrophage uptake of E. coli in vitro and confirm that it limits neutrophilic infiltration in vivo in a murine model of peritonitis. The physical properties of the new synthetic 17-epi-NPD1/17-epi-PD1, namely its ultra-violet absorbance, chromatography, and tandem mass spectrometry fragmentation pattern, matched those of the originally synthesized 17-epi-NPD1/17-epi-PD1. In addition, we verified the structure and complete stereochemical assignment of this new synthetic 17-epi-NPD1/17-epi-PD1 using nuclear magnetic resonance (NMR) spectroscopy. Together, these results authenticate this 17-epi-NPD1/17-epi-PD1 for its structure and potent pro-resolving functions.

Effects of Levofloxacin, Aztreonam, and Colistin on Enzyme Synthesis by P. aeruginosa Isolated from Cystic Fibrosis Patients

(1) Background: Cystic fibrosis (CF) is characterized by chronic pulmonary inflammation and persistent bacterial infections. P. aeruginosa is among the main opportunistic pathogens causing infections in CF. P. aeruginosa is able to form a biofilm, decreasing antibiotic permeability. LOX, a lipoxygenase enzyme, is a virulence factor produced by P. aeruginosa and promotes its persistence in lung tissues. The aim of this study is to evaluate if antibiotics currently used for aerosol therapy in CF are able to interfere with the production of lipoxygenase from open isolates of P. Aeruginosa from patients with CF. (2) Methods: Clinical isolates of P. aeruginosa from patients with CF were grown in Luria broth (LB). Minimum inhibitory concentration (MIC) was performed and interpreted for all isolated strains according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. We selected four antibiotics with different mechanisms of action: aztreonam, colistin, amikacin, and levofloxacin. We used human pulmonary epithelial NCI-H929 cells to evaluate LOX activity and its metabolites according to antibiotic action at increasing concentrations. (3) Results: there is a correlation between LOX secretion by clinical isolates of P. aeruginosa and biofilm production. Levofloxacin exhibits highly significant inhibitory activity compared to the control. Amikacin also exhibits significant inhibitory activity against LOX production. Aztreonam and colistin do not show inhibitory activity. These results are also confirmed for LOX metabolites. (4) Conclusions: among the evaluated antibiotics, levofloxacin and amikacin have an activity on LOX secretion.

Virulence Factors of Pseudomonas Aeruginosa and Antivirulence Strategies to Combat Its Drug Resistance

Pseudomonas aeruginosa is an opportunistic pathogen causing nosocomial infections in severely ill and immunocompromised patients. Ubiquitously disseminated in the environment, especially in hospitals, it has become a major threat to human health due to the constant emergence of drug-resistant strains. Multiple resistance mechanisms are exploited by P. aeruginosa, which usually result in chronic infections difficult to eradicate. Diverse virulence factors responsible for bacterial adhesion and colonization, host immune suppression, and immune escape, play important roles in the pathogenic process of P. aeruginosa. As such, antivirulence treatment that aims at reducing virulence while sparing the bacterium for its eventual elimination by the immune system, or combination therapies, has significant advantages over traditional antibiotic therapy, as the former imposes minimal selective pressure on P. aeruginosa, thus less likely to induce drug resistance. In this review, we will discuss the virulence factors of P. aeruginosa, their pathogenic roles, and recent advances in antivirulence drug discovery for the treatment of P. aeruginosa infections.

Role of Host and Bacterial Lipids in Pseudomonas aeruginosa Respiratory Infections

The opportunistic pathogen Pseudomonas aeruginosa is one of the most common agents of respiratory infections and has been associated with high morbidity and mortality rates. The ability of P. aeruginosa to cause severe respiratory infections results from the coordinated action of a variety of virulence factors that promote bacterial persistence in the lungs. Several of these P. aeruginosa virulence mechanisms are mediated by bacterial lipids, mainly lipopolysaccharide, rhamnolipid, and outer membrane vesicles. Other mechanisms arise from the activity of P. aeruginosa enzymes, particularly ExoU, phospholipase C, and lipoxygenase A, which modulate host lipid signaling pathways. Moreover, host phospholipases, such as cPLA2α and sPLA2, are also activated during the infectious process and play important roles in P. aeruginosa pathogenesis. These mechanisms affect key points of the P. aeruginosa-host interaction, such as: i) biofilm formation that contributes to bacterial colonization and survival, ii) invasion of tissue barriers that allows bacterial dissemination, iii) modulation of inflammatory responses, and iv) escape from host defenses. In this mini-review, we present the lipid-based mechanism that interferes with the establishment of P. aeruginosa in the lungs and discuss how bacterial and host lipids can impact the outcome of P. aeruginosa respiratory infections.

Microbiological quality analysis of inoculants based on Bradyrhizobium spp. and Azospirillum brasilense produced "on farm" reveals high contamination with non-target microorganisms

The use of inoculants carrying diazotrophic and other plant growth-promoting bacteria plays an essential role in the Brazilian agriculture, with a growing use of microorganism-based bioproducts. However, in the last few years, some farmers have multiplied microorganisms in the farm, known as "on farm" production, including inoculants of Bradyrhizobium spp. for soybean (Glycine max L. Merrill.) and Azospirillum brasilense for corn (Zea mays L.) or co-inoculation in soybean. The objective was to assess the microbiological quality of such inoculants concerning the target microorganisms and contaminants. In the laboratory, 18 samples taken in five states were serial diluted and spread on culture media for obtaining pure and morphologically distinct colonies of bacteria, totaling 85 isolates. Molecular analysis based on partial sequencing of the 16S rRNA gene revealed 25 genera of which 44% harbor species potentially pathogenic to humans; only one of the isolates was identified as Azospirillum brasilense, whereas no isolate was identified as Bradyrhizobium. Among 34 isolates belonging to genera harboring species potentially pathogenic to humans, 12 had no resistance to antibiotics, six presented intrinsic resistance, and 18 presented non-intrinsic resistance to at least one antibiotic. One of the samples analyzed with a shotgun-based metagenomics approach to check for the microbial diversity showed several genera of microorganisms, mainly Acetobacter (~ 32% of sequences) but not the target microorganism. The samples of inoculants produced on farm were highly contaminated with non-target microorganisms, some of them carrying multiple resistances to antibiotics.

Croix CM, Watkins SC, Wenzel SE, Mallampalli RK, Greenberger JS, Bayır H, Kagan VE, Tyurina YY. P. aeruginosa augments irradiation injury via 15-lipoxygenase-catalyzed generation of 15-HpETE-PE and induction of theft-ferroptosis

Total body irradiation (TBI) targets sensitive bone marrow hematopoietic cells and gut epithelial cells, causing their death and inducing a state of immunodeficiency combined with intestinal dysbiosis and nonproductive immune responses. We found enhanced Pseudomonas aeruginosa (PAO1) colonization of the gut leading to host cell death and strikingly decreased survival of irradiated mice. The PAO1-driven pathogenic mechanism includes theft-ferroptosis realized via (a) curbing of the host antiferroptotic system, GSH/GPx4, and (b) employing bacterial 15-lipoxygenase to generate proferroptotic signal - 15-hydroperoxy-arachidonoyl-PE (15-HpETE-PE) - in the intestines of irradiated and PAO1-infected mice. Global redox phospholipidomics of the ileum revealed that lysophospholipids and oxidized phospholipids, particularly oxidized phosphatidylethanolamine (PEox), represented the major factors that contributed to the pathogenic changes induced by total body irradiation and infection by PAO1. A lipoxygenase inhibitor, baicalein, significantly attenuated animal lethality, PAO1 colonization, intestinal epithelial cell death, and generation of ferroptotic PEox signals. Opportunistic PAO1 mechanisms included stimulation of the antiinflammatory lipoxin A4, production and suppression of the proinflammatory hepoxilin A3, and leukotriene B4. Unearthing complex PAO1 pathogenic/virulence mechanisms, including effects on the host anti/proinflammatory responses, lipid metabolism, and ferroptotic cell death, points toward potentially new therapeutic and radiomitigative targets.

Potential Therapeutic Targets for Combination Antibody Therapy against Pseudomonas aeruginosa Infections

Despite advances in antimicrobial therapy and even the advent of some effective vaccines, Pseudomonas aeruginosa (P. aeruginosa) remains a significant cause of infectious disease, primarily due to antibiotic resistance. Although P. aeruginosa is commonly treatable with readily available therapeutics, these therapies are not always efficacious, particularly for certain classes of patients (e.g., cystic fibrosis (CF)) and for drug-resistant strains. Multi-drug resistant P. aeruginosa infections are listed on both the CDC’s and WHO’s list of serious worldwide threats. This increasing emergence of drug resistance and prevalence of P. aeruginosa highlights the need to identify new therapeutic strategies. Combinations of monoclonal antibodies against different targets and epitopes have demonstrated synergistic efficacy with each other as well as in combination with antimicrobial agents typically used to treat these infections. Such a strategy has reduced the ability of infectious agents to develop resistance. This manuscript details the development of potential therapeutic targets for polyclonal antibody therapies to combat the emergence of multidrug-resistant P. aeruginosa infections. In particular, potential drug targets for combinational immunotherapy against P. aeruginosa are identified to combat current and future drug resistance.

Pseudomonas aeruginosa necrotizing bronchopneumonia

Extremely low birth weight (ELBW) infants are at particularly high risk for infection due to an immature immune system, invasive procedures such as endotracheal intubation, intravascular catheterization, and other factors. Neonatal infections in this population are associated with a high mortality, poor growth, and neurodevelopmental outcomes. Pseudomonas aeruginosa (P. aeruginosa) infection is an uncommon but potentially devastating cause of pneumonia and sepsis in the ELBW population. P. aeruginosa is an important cause of healthcare-associated infections (HAI) or nosocomial infections. P. aeruginosa can perceive unfavorable environmental changes and orchestrate adaptations by developing plasmid-mediated and adaptive resistance to antibiotics. We describe an ELBW infant born at 26 weeks’ gestation who succumbed at 13 days of life to P. aeruginosa infection. Some of the factors related to the pathogenesis and multidrug resistance are described.

Identification of small molecules that interfere with c-di-GMP signaling and induce dispersal of Pseudomonas aeruginosa biofilms

Microbial biofilms are involved in a number of infections that cannot be cured, as microbes in biofilms resist host immune defenses and antibiotic therapies. With no strict biofilm-antibiotic in the current pipelines, there is an unmet need for drug candidates that enable the current antibiotics to eradicate bacteria in biofilms. We used high-throughput screening to identify chemical compounds that reduce the intracellular c-di-GMP content in Pseudomonas aeruginosa. This led to the identification of a small molecule that efficiently depletes P. aeruginosa for c-di-GMP, inhibits biofilm formation, and disperses established biofilm. A combination of our lead compound with standard of care antibiotics showed improved eradication of an implant-associated infection established in mice. Genetic analyses provided evidence that the anti-biofilm compound stimulates the activity of the c-di-GMP phosphodiesterase BifA in P. aeruginosa. Our work constitutes a proof of concept for c-di-GMP phosphodiesterase-activating drugs administered in combination with antibiotics as a viable treatment strategy for otherwise recalcitrant infections.

Bacterial adaptation strategies to host-derived fatty acids

Fatty acids (FAs) are potent antimicrobials which hold great promise as viable alternatives or complements to conventional antibiotics. Intriguingly, bacteria are well equipped to use environmental FAs as energy sources and/or building blocks for their membrane lipids. Furthermore, these microbes display a wide array of mechanisms to prevent or mitigate FA toxicity. In this review we discuss strategies that bacteria use to thrive despite extensive exposure to host-derived antimicrobial FAs. We also highlight the altered response of these FA-adapted bacteria to antibiotics. Given the ubiquitous nature of FAs in various host environments, deciphering bacterial adaptation strategies to FAs is of prime importance. This knowledge may pave the way for a rational design of FA-based combination therapies with antibiotics.

Pseudomonas aeruginosa in bronchiectasis: infection, inflammation, and therapies

Introduction: Bronchiectasis is a chronic endobronchial suppurative disease characterized by irreversibly dilated bronchi damaged by repeated polymicrobial infections and predominantly, neutrophilic airway inflammation. Some consider bronchiectasis a syndromic consequence of several different causes whilst others view it as an individual disease entity. In most patients, identifying an underlying cause remains challenging. The acquisition and colonization of affected airways by Pseudomonas aeruginosa represent a critical and adverse clinical consequence for its progression and management.Areas covered: In this review, we outline clinical and pre-clinical peer-reviewed research published in the last 5 years, focusing on the pathogenesis of bronchiectasis and the role of P. aeruginosa and its virulence in shaping host inflammatory and immune responses in the airway. We further detail its role in airway infection, the lung microbiome, and address therapeutic options in bronchiectasis.Expert opinion: P. aeruginosa represents a key pulmonary pathogen in bronchiectasis that causes acute and/or chronic airway infection. Eradication can prevent adverse clinical consequence and/or disease progression. Novel therapeutic strategies are emerging and include combination-based approaches. Addressing airway infection caused by P. aeruginosa in bronchiectasis is necessary to prevent airway damage, loss of lung function and exacerbations, all of which contribute to adverse clinical outcome.

Comparative proteomic profiling of newly acquired, virulent and attenuated Neoparamoeba perurans proteins associated with amoebic gill disease

The causative agent of amoebic gill disease, Neoparamoeba perurans is reported to lose virulence during prolonged in vitro maintenance. In this study, the impact of prolonged culture on N. perurans virulence and its proteome was investigated. Two isolates, attenuated and virulent, had their virulence assessed in an experimental trial using Atlantic salmon smolts and their bacterial community composition was evaluated by 16S rRNA Illumina MiSeq sequencing. Soluble proteins were isolated from three isolates: a newly acquired, virulent and attenuated N. perurans culture. Proteins were analysed using two-dimensional electrophoresis coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). The challenge trial using naïve smolts confirmed a loss in virulence in the attenuated N. perurans culture. A greater diversity of bacterial communities was found in the microbiome of the virulent isolate in contrast to a reduction in microbial community richness in the attenuated microbiome. A collated proteome database of N. perurans, Amoebozoa and four bacterial genera resulted in 24 proteins differentially expressed between the three cultures. The present LC-MS/MS results indicate protein synthesis, oxidative stress and immunomodulation are upregulated in a newly acquired N. perurans culture and future studies may exploit these protein identifications for therapeutic purposes in infected farmed fish.

16HBE Cell Lipid Mediator Responses to Mono and Co-Infections with Respiratory Pathogens

Respiratory tract infections are a global health problem. The main causative agents of these infections are influenza A virus (IAV), Staphylococcus aureus (S. aureus), and Streptococcus pneumoniae (S. pneumoniae). Major research focuses on genetics and immune responses in these infections. Eicosanoids and other oxylipins are host-derived lipid mediators that play an important role in the activation and resolution of inflammation. In this study, we assess, for the first time, the different intracellular profiles of these bioactive lipid mediators during S. aureus LUG2012, S. pneumoniae TIGR4, IAV, and corresponding viral and bacterial co-infections of 16HBE cells. We observed a multitude of altered lipid mediators. Changes in the amount of 5-hydroxyeicosatetraenoic acid (5-HETE) were prominent for all bacterial infections. The infection with S. pneumoniae showed the strongest impact on bioactive lipid production and led to alterations in the amount of PPARγ ligands and precursors of pro-resolving lipid mediators.