In vitro antibacterial and antibiofilm activities of chlorogenic acid against clinical isolates of stenotrophomonas maltophilia including the trimethoprim / sulfamethoxazole resistant strain

The in vitro antibacterial and antibiofilm activity of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia was investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill and biofilm assays. A total of 9 clinical S. maltophilia isolates including one isolate resistant to trimethoprim / sulfamethoxazole (TMP/SMX) were tested. The inhibition zone sizes for the isolates ranged from 17 to 29 mm, while the MIC and MBC values ranged from 8 to 16 g mL-1 and 16 to 32 g mL-1. Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2-log reduction in viable bacteria at 10 h. In vitro antibiofilm testing showed a 4-fold reduction in biofilm viability at 4x MIC compared to 1x MIC values (0.085 < 0.397 A 490 nm) of chlorogenic acid. The data from this study support the notion that the chlorogenic acid has promising in vitro antibacterial and antibiofilm activities against S. maltophilia

Eryptotic Phenotype in Chronic Myeloid Leukemia: Contribution of Neutrophilic Cathepsin G

In pathological conditions with concurrent neutrophilia, modifications of erythrocyte membrane proteins are reported. In chronic myeloid leukemia (CML), a myeloproliferative disease wherein neutrophilia is accompanied by enhanced erythrophagocytosis, we report for the first time excessive cleavage of erythrocyte band 3. Distinct fragments of band 3 serve as senescent cell antigens leading to erythrophagocytosis. Using immunoproteomics, we report the identification of immunogenic 43 kDa fragment of band 3 in 68% of CML samples compared to their detection in only 38% of healthy individuals. Thus, excessive fragmentation of band 3 in CML, detected in our study, corroborated with the eryptotic phenotype. We demonstrate the role of neutrophilic cathepsin G, detected as an immunogen on erythrocyte membrane, in band 3 cleavage. Cathepsin G from serum adsorbs to the erythrocyte membrane to mediate cleavage of band 3 and therefore contribute to the eryptotic phenotype in CML

Curcumin-loaded sterically stabilized nanodispersion based on non-ionic colloidal system induced by ultrasound and solvent diffusion-evaporation

Curcumin has been found to possess significant pharmaceutical activities. However, owing to its low bioavailability, there is a limitation of employing it towards clinical application. In an attempt to surmount this implication, often the choice is designing novel drug delivery systems. Herein, sterically stabilized nanoscale dispersion loaded with curcumin (nanodispersion) based on non-ionic colloidal system has been proposed. In this study, the process conditions were effectively optimized using response surface methodology (RSM) with Box–Behnken design (BBD). The suggested optimum formulation proved to be an excellent fit to the actual experimental output. STEM images illustrate that the optimal curcumin-loaded nanodispersion has spherical morphology with narrow particle size distribution. Particle size distribution study confirms that the solution pH does not affect the nanodispersion, and physical stability study shows that the colloidal system is stable over 90 days of storage at ambient conditions. More importantly, controlled release profile was achieved over 72 h and the in vitro drug release data fit well to Higuchi model (R2=0.9654)

Elucidating pathogenic determinants in stenotrophomonas maltophilia pathogenesis

Stenotrophomonas maltophilia, Gram negative bacteria has been known to be an environmental microbe with numerous biotechnological applications. They are ubiquitously found in nature. In recent times, this bacterium has been documented to be one of the leading nosocomial pathogen next to Pseudomonas aeruginosa. Owing to the high incident rate in hospital setup, they have been ranked as an opportunistic pathogen and have been associated with bacteremic infection and pneumonia, both with high rate of mortality in immunocompromised patients. Mortality rate has been found to be high with patients who have a history of prolonged hospitalization,malignancy, neutropenia, immune suppression, breakdown of mucocutaneous defence barriers (e.g., following catheterization, artificial implantation, tracheotomy,or peritoneal dialysis), exposure to broad spectrum antibiotics and those requiring mechanical ventilation. Their intrinsic/acquired resistance to most antibiotics and their ability to colonize surfaces of medical devices makes S. maltophilia a potentially dangerous pathogen. Treatment of S. maltophilia infections is also complicated by the fact that isolates are inherently resistant to many of the currently available broad-spectrum agent including carbapenems. Whether S. maltophilia clinical isolates are colonizers or true pathogens is still controversial. Despite the increase in the spectrum of clinical syndromes associated with S. maltophilia, very little is known about the extracellular enzymes profiles which may have potential roles in pathogenesis especially among clinical isolates associated with infections. In this study, we screened and compared an array of extracellular enzymes in S.maltophilia collected from invasive and non-invasive clinical specimens by substrate plate assays. We also grouped the isolates as device related and non-device related and compared the enzyme profile. Our study showed all clinical isolates produced substantial levels of biochemical enzyme assayed. However, lecithinase and heparinase were significantly associated with isolates of invasive origin. In contrast, device related and non-device related did not show an major significant difference. These data suggest that clinical isolates of S. maltophila are a reservoir for pathogenic potential enzymes. The pathogenic potential of S. maltophilia strains isolated from clinical samples were screened for a panel of putative virulent genes such asputative lipase, putative iron complex outer membrane [ICOM], putative siderophore, lux R, toxA, piliZ and tatD which were fished out from closely related P. aeruginosa genome. The results showed that among the 108 isolates, 57.4%, 10.1%, 0.92%, 57.4% and 74% of the isolates harboured ICOM (n = 62), siderophore (n = 11), luxR (n = 1), Lipase (n =62) and tatD (n = 80) harboured these genes. ToxA and piliz were not found in these clinical isolates. Relative quantification of these putative virulent genes showed ICOM, tatD and lipase genes to be overexpressed compared to others. Environmental strain S. maltophilia LMG 959 lacked these putative virulent genes. The role of S. maltophilia on macrophages was studied to determine the inflammatory response and to study the phagocytic ability of this bacterium on RAW 264.7 macrophages. Both invasive and non-invasive isolates of S. maltophilia were able to enter the macrophage cells. Greater internalization ability was observed by clinical isolates ofS.maltophilia in comparison to that of the environmental strain. S. maltophilia LMG959 (p < 0.05). Although all isolates of S. maltophilia gained entry, only the clinical isolates were able to replicate within the macrophages. Environmental strain was unable to replicate within the macrophage. The ability of clinical isolates of S. maltophilia to enter and survive the macrophages indicates its resistance to host defence system. Clinical isolates of S. maltophilia induced an amplified level of activation within macrophages which triggered immune response compared to environmental strains, as revealed by increased nitric oxide production and CD40 expression. Intracellular survivability of S. maltophilia was also ascertained by the presence of several bacteria which were observed as membrane bound. This intracellular phase during infection could play a prominent role in immune evasion and its pathogenicity. In conclusion, S. maltophilia has all the essential qualities to be termed as a serious nosocomial pathogen with the presence of these virulence factors such as the extracellular enzymes and the gene products which could have a deleterious effect owing to the fact that the virulent determinants act in combination. Evading host defences and having intracellular survival ability makes this bacterium a potent and serious nosocomial pathogen

In Vitro Anti�acterial and Anti�io�lm Activities of Chlorogenic Acid against Clinical Isolates of Stenotrophomonas maltophilia including the Trimethoprim/Sulfamethoxazole Resistant Strain

e in vitro antibacterial and antibio�lm activity of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia was investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), timekill and bio�lm assays. A total of 9 clinical S. maltophilia isolates including one isolate resistant to trimethoprim/sulfamethoxazole (TMP/SMX) were tested. e inhibition zone sizes for the isolates ranged from 17 to 29 mm, while the MIC and MBC values ranged from 8 to 16 g mL −1 and 16 to 32 g mL −1 . Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2-log reduction in viable bacteria at 10 h. In vitro antibio�lm testing showed a 4-fold reduction in bio�lm viability at 4x MIC compared to 1x MIC values (0.085 &lt; 0.397 A 490 nm) of chlorogenic acid. e data from this study support the notion that the chlorogenic acid has promising in vitro antibacterial and antibio�lm activities against S. maltophilia