Detection of biofilms and their interaction in wound infection: role of N-ACYL homoserine lacton and other virulence factors in enhancement of biofilm formation

The deleterious effect of microbial infection on wound healing has been recognized for decades and control of bioburden is considered as an important aspect of wound management. Biofilms play a role in prevention of wound healing. Biofilm-related diseases are typically persistent infections. The aim of this study involves assessment of wound infection through isolation and identification of infected wound-associated pathogens, determination of their ability for biofilm formation, study of interspecies interaction and their antimicrobial resistance pattern. A total of 52 swabs taken from different wounds revealed 80 isolates, that were identified by cultural, microscopic and biochemical tests. These isolates were examined for their biofilm forming capacity by modified microtiter plate assay. For selected culture mates, some virulence factors, which are involved in quorum sensing as well as production of N-Acyl homoserine lactone were determined. Furthermore, antibiotic susceptibility testing of all isolates was done. In total, 27% of the isolates were Pseudomonas species, 33% Staphylococcus aureus, 19% coagulase negative staphylococci, 15% Escherichia coli, 1% and 5% Klebsiella and Proteus species, respectively. All Pseudomonas and Staphylococcus isolates were biofilm formers but with different intensities. Among Pseudomonas and Staphylococcus isolates, 29% and 11% were strong biofilm formers, respectively. All the Pseudomonas isolates were N-Acyl homoserine lactone-producers but with different intensity in its production. A relation between the level of N-Acyl homoserine lactone-production and the expression of virulence factors was observed. A multidrug resistance pattern was observed throughout the different isolates. Biofilm is highly implicated in wound infections caused by either single or mixed species demonstrating a multidrug resistance pattern. Such behavior along with other virulence factors might be controlled by quorum sensing in case of Pseudomonas species and the production of N-Acyl homoserine lactones signaling molecules

Serum levels of matrix metalloproteinase-9 [MMP-9] and caspase-3 activity in chronic hepatitis C patients

During Hepatitis C virus infections, liver fibrosis results as a consequence of a progressive accumulation of extracellular matrix [ECM] proteins. While, matrix metalloproteinase-9 [MMP-9] has major actions in remodeling of ECM components, caspase-3 plays a key role in the execution of apoptosis implicated in HCV pathogenesis. The assessment of liver disease severity as well as monitoring of patients with chronic liver disease over time remains a major challenge nowadays. Thus, an urgent need to develop noninvasive reliable tests to monitor hepatic disease activity, especially serum biomarkers emerges. This study was conducted to evaluate serum levels of MMP-9 and caspase-3 in patients with chronic hepatitis C and their potential use as markers of hepatic impairment. Forty chronic HCV patients together with 20 healthy controls were enrolled in the present work. HCV viral load was evaluated by Real-time PCR. In addition, caspase-3 serum levels were measured using Instant ELISA and MMP-9 serum levels were measured by ELISA. Besides, serum aminotransferases' activities were measured by automated analyzer. Caspase-3 activity and MMP-9 levels were markedly elevated in the HCV patients' sera compared to controls [56.40 +/- 22.52 vs. 5.20 +/- 6.65 ng/ml; 190.29 +/- 144.16 v. 39.10 +/- 17.68 ng/ml, p<0.001, respectively]. Patients with AST/ALT ratio>1 demonstrated higher MMP-9 serum levels than those with ratio <1[p<0.001]. The same was observed for caspase-3; however, it did not reach statistical significance. A significant correlation was observed between these markers and AST as well as AST/ALT ratio. However, no correlation was observed with the viral load. MMP-9 and caspase-3 might be involved in HCV-associated liver injury. Measurement of MMP-9 and caspase-3 activities could be reliable markers for liver damage, which may open up new diagnostic and therapeutic strategies aimed at manipulating the early inflammation as well as the late fibrotic changes in HCV infection