Background: Non-typeable Haemophilus influenzae (NTHi) has become the major cause of invasive H. influenzae diseases in the post-H. influenzae type b vaccine era. The emergence of multidrug-resistant (MDR) NTHi is a growing public health problem. Herein, we investigated the molecular basis of MDR in NTHi. The isolated NTHi were subjected to antimicrobial susceptibility testing for 12 agents. Whole genome and plasmid sequencing were conducted and analyzed to identify significant genetic variations and plasmid-encoded genes conferred antibiotic resistance. Results: Thirteen (50%) MDR NTHi isolates were obtained; of these, 92.3% were non-susceptible to ampicillin, 30.8% to amoxicillin-clavulanate, 61.5% to cefuroxime, 61.5% to ciprofloxacin/levofloxacin, 92.3% to trimethoprim-sulfamethoxazole, 30.8% to tetracycline, and 7.7% to azithromycin. Eight ampicillin-resistant isolates were β-lactamase positive; of these, 6 carried bla_TEM-1 and 2 carried bla_ROB-1, whereas 4 were β-lactamase negative. Genetic variations in mrdA, mepA, and pbpG were correlated with amoxicillin-clavulanate non-susceptibility, whereas variations in ftsI and lpoA conferred cefuroxime resistance. Five variations in gyrA, 2 in gyrB, 3 in parC, 1 in parE, and 1 in the parC-parE intergenic region were associated with levofloxacin/ciprofloxacin non-susceptibility. Among these genes, 8 variations were linked to high-level levofloxacin resistance. Six variations in folA were associated with trimethoprim-sulfamethoxazole resistance. Plasmid-bearing tet(B) and mef(A) genes were responsible for tetracycline and azithromycin resistance in 4 and 1 MDR isolates, respectively. Conclusions: This study clarified the molecular epidemiology of MDR in NTHi. This can benefit the monitoring of drug resistance trends in NTHi and the adequate medical management of patients with NTHi infection.

Trichomonas vaginalis is parasitic protozoan that causes human urogenital infections. Accumulated reports indicated that exosomes released by this parasite play a crucial role in transmitting information and substances between cells during host-parasite interactions. Current knowledge on the protein contents in T. vaginalis exosome is mainly generated from three previous studies that used different T. vaginalis isolates as an experimental model. Whether T. vaginalis exosomes comprise a common set of proteins (core exosome proteome) is still unclear. To explore the core exosome proteome in T. vaginalis, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the contents of sucrose ultracentrifugation-enriched exosome and supernatant fractions isolated from six isolates. Transmission electron microscopy (TEM) confirmed the presence of exosomes in the enriched fraction. Proteomic analysis identified a total of 1870 proteins from exosomal extracts. There were 1207 exosomal-specific proteins after excluding 436 'non-core exosomal proteins'. Among these, 72 common exosomal-specific proteins were expressed in all six isolates. Compared with three published T. vaginalis exosome proteome datasets, we identified 16 core exosomal-specific proteins. These core exosomal-specific proteins included tetraspanin (TvTSP1), the classical exosome marker, and proteins mainly involved in catalytic activity and binding such as ribosomal proteins, ras-associated binding (Rab) proteins, and heterotrimeric G proteins. Our study highlighted the importance of using supernatant fraction from exosomal extract as a control to eliminate 'non-core exosomal proteins'. We compiled a reference core exosome proteome of T. vaginalis, which is essential for developing a fundamental understanding of exosome-mediated cell communication and host-parasite interaction.

Background: Iron is an essential element for cellular functions, such as energy metabolism. Trichomonas vaginalis, a human urogenital tract pathogen, is capable of surviving in the environment without sufficient iron supplementation. Pseudocysts (cyst-like structures) are an environmentally tolerated stage of this parasite while encountering undesired conditions, including iron deficiency. We previously demonstrated that iron deficiency induces more active glycolysis but a drastic downregulation of hydrogenosomal energy metabolic enzymes. Therefore, the metabolic direction of the end product of glycolysis is still controversial. Methods: In the present work, we conducted an LC‒MS-based metabolomics analysis to obtain accurate insights into the enzymatic events of T. vaginalis under iron-depleted (ID) conditions. Results: First, we showed the possible digestion of glycogen, cellulose polymerization, and accumulation of raffinose family oligosaccharides (RFOs). Second, a medium-chain fatty acid (MCFA), capric acid, was elevated, whereas most detected C18 fatty acids were reduced significantly. Third, amino acids were mostly reduced, especially alanine, glutamate, and serine. Thirty-three dipeptides showed significant accumulation in ID cells, which was probably associated with the decrease in amino acids. Our results indicated that glycogen was metabolized as the carbon source, and the structural component cellulose was synthesized at same time. The decrease in C18 fatty acids implied possible incorporation in the membranous compartment for pseudocyst formation. The decrease in amino acids accompanied by an increase in dipeptides implied incomplete proteolysis. These enzymatic reactions (alanine dehydrogenase, glutamate dehydrogenase, and threonine dehydratase) were likely involved in ammonia release. Conclusion: These findings highlighted the possible glycogen utilization, cellulose biosynthesis, and fatty acid incorporation in pseudocyst formation as well as NO precursor ammonia production induced by iron-depleted stress. Graphical

Neutrophils are vital constituents of the immune response in the vaginal environment, playing a pivotal role in the defense against trichomoniasis. Earlier studies have shown that Trichomonas vaginalis (T. vaginalis) can release leukotriene B4 (LTB4), a molecule that attracts and activates neutrophils. Additionally, secretory products from this parasite can induce the production of interleukin-8 (IL-8) in mast cells and neutrophils, which further recruits neutrophils to the infection site. The precise reasons behind T. vaginalis actively promoting interaction between parasites and neutrophils rather than inhibiting the inflammatory response remain unclear. In this study, we collected conditioned medium to elucidate the intricate dynamics between T. vaginalis and human neutrophils. We conducted a comprehensive profiling of soluble excretory/secretory proteins (ESPs), identifying 192 protein spots, of which 94 were successfully characterized through mass spectrometry analysis. Notably, the majority of induced ESPs from co-cultivation exhibited consistency with the trichomonad and neutrophil standalone groups, except for lactoferrin, which was observed exclusively following the interaction between neutrophils and T. vaginalis. The secretion of lactoferrin was determined to be a contact-dependent process. It was interesting to identify the ability of the iron-loaded lactoferrin to extend the survival time of T. vaginalis under iron-deficient conditions. This study represents the first to identify the origin of lactoferrin during T. vaginalis infection, shedding light on the potential reason for T. vaginalis's ability to attract neutrophils to the infection site: the acquisition of the iron source, lactoferrin.

Acanthamoeba castellanii is a free-living protist that feeds on diverse bacteria. A. castellanii has frequently been utilized in studies on microbial interactions. Grazing bacteria also exhibit diverse effects on the physiological characteristics of amoebae, such as their growth, encystation, and cytotoxicity. Since the composition of amoebae amino acids is closely related to cellular activities, it can indicate the overall responses of A. castellanii to various stimuli. A. castellanii was exposed to different culture conditions in low-nutrient medium with heat-killed DH5α to clarify their effects. A targeted metabolomic technique was utilized to evaluate the concentration of cellular amino acids. The amino acid composition and pathways were analyzed by two web-based tools: MetaboAnalyst and Pathview. Then, long-term exposure to A. castellanii was investigated through in silico and in vitro methods to elucidate the homeostasis of amino acids and the growth of A. castellanii. Under short-term exposure, all kinds of amino acids were enriched in all exposed groups. In contrast to the presence of heat-killed bacteria, the medium exhibited obvious effects on the amino acid composition of A. castellanii. After long-term exposure, the amino acid composition was more similar to that of the control group. A. castellanii may achieve amino acid homeostasis through pathways related to alanine, aspartate, citrulline, and serine. Under short-term exposure, compared to the presence of bacteria, the type of medium exerted a more powerful effect on the amino acid composition of the amoeba. Previous studies focused on the interaction of the amoeba and bacteria with effective secretion systems and effectors. This may have caused the effects of low-nutrient environments to be overlooked. When A. castellanii was stimulated in the coculture system through various methods, such as the presence of bacteria and a low-nutrient environment, it accumulated intracellular amino acids within a short period. However, different stimulations correspond to different amino acid compositions. After long-term exposure, A. castellanii achieved an amino acid equilibrium by downregulating the biosynthesis of several amino acids.

Trichomonas vaginalis is recognized as the most prevalent non-viral sexually transmitted parasitic infection, establishing its presence in the vaginal microbiota alongside commensal bacteria, particularly Lactobacillus and Bifidobacterium species. Notably, a reduction in the population of Bifidobacterium breve has been documented in women infected with T. vaginalis. However, the dynamics of the interaction between T. vaginalis and these beneficial bacterial species remain inadequately understood, warranting further investigation to elucidate the underlying mechanisms and potential implications for vaginal health. We investigated the effects of B. breve on the growth of T. vaginalis, including its gene expression and interactions with the host. HeLa cells were exposed to T. vaginalis that had been pretreated with or without B. breve. We assessed cytokine responses (specifically IL-6 and IL-8) and evaluated cytopathic effects. The dynamics of the co-culture were monitored microscopically. Additionally, we conducted transcriptomic and metabolomic analyses to characterize the responses of T. vaginalis to B. breve. Co-culture of T. vaginalis with B. breve for 4 h significantly increased protozoan proliferation by 1.2-fold, while bacterial abundance was reduced by 27%. HeLa cells showed no cytopathic effects or changes after treatment with B. breve, whether given before or alongside T. vaginalis. Microscopy showed a direct physical association between the two organisms. Transcriptomic profiling of T. vaginalis co-cultured with B. breve revealed an upregulation of genes related to fatty acid metabolism and DNA replication. Metabolomic analysis confirmed changes in the content of long-chain fatty acids. Additionally, there was an increase in virulence-associated genes, including adhesins. B. breve promotes the growth of T. vaginalis and modulates parasite gene expression and lipid metabolism transiently. However, it does not confer protection on host epithelial cells during infection. These findings suggest that B. breve may contribute to maintaining microbial community balance but does not directly counteract T. vaginalis. Importantly, these insights highlight the potential value of B. breve–associated microbial or metabolic signatures as indicators of ecological shifts that predispose to parasite overgrowth.