Uropathogens and the Lower Urinary Tract
Linda Cardozo, Staskin David in Textbook of Female Urology and Urogynecology - Two-Volume Set, 2017
leAd to AlterAtions in host response to pAthogens [23]. In the Urinary trAct, severAl tLr polymorphisms Are AssociAted with either increAsed susceptibility to or greAter protection from UTI As well As number of UTI episodes [24]. There Are severAl known toxins thAt modulAte the host inflAmmAtory response, induce cytopAthic effects, And cAuse tissue dAmAge. AlphA-hemolysin promotes cell lysis, AppeArs to AttenuAte the host inflAmmAtory response, And is AssociAted with clinicAl severity [25,26]. Cytotoxic necrotizing fActor 1 (CnF1) hAs been shown to cAuse membrAne chAnges thAt fAcilitAte bActeriAl internAlizAtion into host cells [27] And inhibit neutrophil Activity in AnimAl models [28]. Iron is required for bActeriAl cellulAr processes And survivAl, And the competition for AvAilAble iron stores highlights the impressive Ability of uPeC to evAde host defenses. one host defense is to limit iron AvAilAbility viA trAnsferrin, An iron cArrier protein thAt cAn move iron stores in And out of cells. However, uPeC cAn utilize enterobActin, which hAs A higher Affinity for iron thAn trAnsferrin And cAn therefore scAvenge iron from the environment [29]. An AdditionAl host protein cAlled lipocAlin 2 specificAlly binds enterobActin And is upregulAted in urotheliAl cells contAining uPeC [30,31]; however, uPeC hAve yet AdditionAl iron Acquisition systems thAt Are not recognized by lipocAlin And cAn therefore work Around this host defense As well [32].
Pathogenicity and Virulence
Julius P. Kreier in Infection, Resistance, and Immunity, 2022
Some bacteria, which apparently do not produce their own siderophores, have specific surface receptors that enable them to make use of the chelators produced by other species. This has been observed in the Campylobacters, shigellae and some salmonellae. Pathogenic Neisseria have their own iron acquisition system consisting of two membrane associated iron-binding proteins, which are regulated by the concentration of iron in the environment. Although most species of bacteria obtain iron from the host′s glycoprotein storage molecules, there is evidence that some are also able to acquire it from hemin. Vibrio cholerae has two types of iron sequestering systems: a siderophore and a surface protein that binds hemin and hemoglobin. Escherichia coli provides another example. The hemolysin of E. coli lyses red blood cells, thus releasing heme, which stimulates the growth of bacteria. Iron obtained by this method can permit development of fatal infections in individuals who have free blood in their abdominal cavity.
Biology of microbes
Philip A. Geis in Cosmetic Microbiology, 2006
When cultured on blood agar, S. aureus produces a clear zone known as β-hemolysis caused by the production of a toxin that lyses red blood cells. The role of the hemolysin in disease is not entirely known. The staphylococci also produce a variety of enzymes such as hyaluronidase, proteinases, lipases, coagulase, and penicillinase. The production of coagulase can be used to confirm in the laboratory that an organism is S. aureus, a potential pathogen. When S. aureus produces coagulase, it clots the serum. Performing this test in a laboratory is relatively simple: the addition of a culture to human or rabbit plasma in a tube; after a brief incubation, the coagulase-positive S. aureus clots the plasma through the formation of a fibrin clot. Its presence in a cosmetic indicates human contamination.
Inhibitory effect of norharmane on Serratia marcescens NJ01 quorum sensing-mediated virulence factors and biofilm formation
Published in Biofouling, 2021
Huai-Zhi Luo, Jin-Wei Zhou, Bing Sun, Huan Jiang, Shi Tang, Ai-Qun Jia
To identify the anti-QS activity of ILEE on S. marcescens NJ01, the virulence factors and biofilm formation by S. marcescens were assayed. Intracellular prodigiosin pigment production is directly regulated by the QS-signaling mechanism of S. marcescens strains from environmental or clinical origins (Slater et al. 2003). Generally, the pigments produced by pathogenic microbes such as Staphylococcus aureus and Pseudomonas aeruginosa are necessary virulence factors for their invasion, survival and lethality, but the prodigiosin produced by S. marcescens is not an essential virulence factor (Liu and Nizet 2009; Zhou et al. 2016). In this study, the prodigiosin was significantly reduced from 87.6% to 94.3% at 0.5 and 2.0 mg ml−1 of ILEE, respectively (Figure 3a). Hemolysin, which is produced by various pathogenic bacteria and has been proposed to be responsible for their pathogenesis (Shimuta et al. 2009), was also significantly reduced from 63.9% to 78.3% (Figure 3d). In addition, the productions of protease, lipase, EPS and biofilm were inhibited by ∼ 38.9%, 37.1%, 39.8% and 54.7% after being exposed to 2.0 mg ml−1 ILEE (Figure 3b, c, e, f).
Pathophysiology and management of Staphylococcus aureus in nasal polyp disease
Published in Expert Review of Clinical Immunology, 2023
Zhaofeng Xu, Jieying Yan, Weiping Wen, Nan Zhang, Claus Bachert
Regarding CRSwNP, single staphylococcal cells may invade the nasal mucosa. In vitro, S. aureus exerts immunomodulatory effects, as demonstrated by IL-6 synthesis, resulting in a local type 2 immune response [38]. In particular, SEB can rapidly trigger a local immune response and disrupt the epithelial barrier integrity and tight junctions by activating Toll-like receptor 2 signaling in primary epithelial cells of patients with CRSwNP [39]. Staphylococcus aureus α-hemolysin (Hla) has a unique function in the pathogenesis of staphylococcal infection, mutant strains lacking Hla leading to less respiratory tract insult in infective models [40]. Hla disturbs the organization of the actin cytoskeleton in airway epithelial model cells, thus limiting the barrier function of the epithelium and making it easy for bacteria to undergo internalization in airway epithelial cells [41]. Furthermore, Hla can accelerate the formation of new complexes, but it may inhibit focal complex maturation, resulting in a loss of focal complexes in the cell periphery and actin stress fibers [42]. Such processes disturb the integrity and barrier function of the airway epithelium. S. aureus V8 protease also serves as a virulent factor that causes dysfunction of the mucosal barrier structure and function [34].
A comprehensive review on phytochemistry, pharmacology, and flavonoid biosynthesis of Scutellaria baicalensis
Published in Pharmaceutical Biology, 2018
Zi-Long Wang, Shuang Wang, Yi Kuang, Zhi-Min Hu, Xue Qiao, Min Ye
Baicalin (100 mg/kg, p.o.) could protect mice from staphylococcal pneumonia caused by Staphylococcus aureus, reducing mortality from 80% to 28% and protecting the lung from accumulation of cellular infiltrates (Qiu et al. 2012). This activity is associated with inhibition of the cytolytic activity of α-hemolysin, which is a self-assembling and channel-forming toxin secreted by S. aureus. Baicalein also showed potent synergistic effect with penicillin G/amoxicillin against 20 clinical penicillinase-producing S. aureus strains. Baicalin at 32 μg/mL could enhance the bacteriostatic effects, and decrease the MIC50 values of penicillin and amoxicillin from 32–64 to 0.5–2 μg/mL (Qian et al. 2015).
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