CXCR1, TLR-4, AND CXCL8: KEY MEDIATORS OF PSEUDOMONAS AERUGINOSA VIRULENCE IN WOUND AND BURN INFECTIONS

AbstractPseudomonas aeruginosa, an opportunistic pathogen of considerable clinical import, presents a formidable challenge to susceptible individuals, particularly within the confines of nosocomial settings. Those with compromised immune systems, indwelling medical devices such as catheters, and extensive thermal injuries are especially vulnerable to its insidious and often devastating effects. This investigation sought to elucidate the roles of Toll-like receptor 4 (TLR-4), Toll-like receptor 5 (TLR-5), the chemokine CXCL8, and its cognate receptor CXCR1 in the context of P. aeruginosa infection. Our findings indicate a significant involvement of TLR-4 and CXCL8 in the host response to this pathogen. Notably, CXCR1 expression was observed to be downregulated both in cellular models and in whole blood samples obtained from patients afflicted with bacterial infections, specifically those caused by P. aeruginosa. Utilizing antibodies targeting these cell surface molecules, we further explored their influence on bacterial adhesion and the modulation of infection. The application of anti-CXCR1 antibodies resulted in a demonstrable increase in bacterial infection in both T24 and A549 cell lines. Conversely, the administration of anti-TLR-4 antibodies exerted an inhibitory effect on P. aeruginosa infection. Anti-CXCL8 antibodies, however, did not elicit a discernible impact on bacterial infection within the initial three hours of exposure. These observations suggest a dichotomous role for these molecules in the host response to P. aeruginosa: CXCR1 appears to function as a negative regulator, while TLR-4 appears to act as a positive regulator in the context of bacterial infection

Antimicrobial cytotoxicity and phytochemical activities of Spilanthes acmella

?-Sitosterone was isolated from the dichloromethane extract of the leaves of Spilanthes acmella. Stigmasterol was isolated from the petroleum and dichloromethane extract respectively. The structures of compounds were elucidated on the basis of spectral analysis as well as by comparison with available literature data. Pet-ether &amp; DCM extract and two column fractions of DCM and one pure compound were subjected to antimicrobial screening &amp; brine shrimp lethality. All of the fractions showed moderate to strong inhibitory activity to microbial growth. On the other hand, the pet ether extract and pure compound (stigmasterol) showed strongest cytotoxicity having LC50 1.2 ?g/mL and 2.02 ?g/mL respectively. Bangladesh J. Sci. Ind. Res. 47(4), 437-440, 2012 DOI: http://dx.doi.org/10.3329/bjsir.v47i4.14073</jats:p