Immune Modulating Topical S100A8/A9 Inhibits Growth of Pseudomonas aeruginosa and Mitigates Biofilm Infection in Chronic Wounds

Pseudomonas aeruginosa biofilm maintains and perturbs local host defense, hindering timely wound healing. Previously, we showed that P. aeruginosa suppressed S100A8/A9 of the murine innate host defense. We assessed the potential antimicrobial effect of S100A8/A9 on biofilm-infected wounds in a murine model and P. aeruginosa growth in vitro. Seventy-six mice, inflicted with a full-thickness burn wound were challenged subcutaneously (s.c.) by 106 colony-forming units (CFUs) of P. aeruginosa biofilm. Mice were subsequently randomized into two treatment groups, one group receiving recombinant murine S100A8/A9 and a group of vehicle controls (phosphate-buffered saline, PBS) all treated with s.c. injections daily for up to five days. Wounds were analyzed for quantitative bacteriology and contents of key inflammatory markers. Count of blood polymorphonuclear leukocytes was included. S100A8/A9-treatment ameliorated wound infection, as evaluated by quantitative bacteriology (p ≤ 0.05). In vitro, growth of P. aeruginosa was inhibited dose-dependently by S100A8/A9 in concentrations from 5 to 40 μg/mL, as determined by optical density-measurement (OD-measurement) and quantitative bacteriology. Treatment slightly augmented key inflammatory cytokine Tumor Necrosis Factor-α (TNF-α), but dampened interferon-γ (IFN-γ) levels and blood polymorphonuclear count. In conclusion, topical S100A8/A9 displays remarkable novel immune stimulatory and anti-infective properties in vivo and in vitro. Importantly, treatment by S100A8/A9 provides local infection control. Implications for a role as adjunctive treatment in healing of chronic biofilm-infected wounds are discussed

Sublethal Ciprofloxacin Treatment Leads to Rapid Development of High-Level Ciprofloxacin Resistance during Long-Term Experimental Evolution of Pseudomonas aeruginosa

The dynamics of occurrence and the genetic basis of ciprofloxacin resistance were studied in a long-term evolution experiment (940 generations) in wild-type, reference strain (PAO1) and hypermutable (PAOΔmutS and PAOMY-Mgm) P. aeruginosa populations continuously exposed to sub-MICs (1/4) of ciprofloxacin. A rapid occurrence of ciprofloxacin-resistant mutants (MIC of ≥12 μg/ml, representing 100 times the MIC of the original population) were observed in all ciprofloxacin-exposed lineages of PAOΔmutS and PAOMY-Mgm populations after 100 and 170 generations, respectively, and in one of the PAO1 lineages after 240 generations. The genetic basis of resistance was mutations in gyrA (C248T and G259T) and gyrB (C1397A). Cross-resistance to beta-lactam antibiotics was observed in the bacterial populations that evolved during exposure to sublethal concentrations of ciprofloxacin. Our study shows that mutants with high-level ciprofloxacin resistance are selected in P. aeruginosa bacterial populations exposed to sub-MICs of ciprofloxacin. This can have implications for the long-term persistence of resistant bacteria and spread of antibiotic resistance by exposure of commensal bacterial flora to low antibiotic concentrations

Neutrophil count in sputum is associated with increased sputum glucose and sputum L-lactate in cystic fibrosis

BackgroundMarkers of lung inflammation measured directly in expectorated sputum have the potential of improving the timing of antibiotic treatment in cystic fibrosis (CF). L-Lactate might be a marker of inflammation, as it is produced from glucose by polymorphonuclear neutrophils (PMNs) in CF lungs. We aimed to investigate changes in and associations between PMNs, glucose and L-lactate in sputum during antibiotic treatment. In addition, the effect of hemoglobin A1c and plasma glucose on these biomarkers were investigated.MethodsWe sampled non-induced sputum at day 0, 7, 14 and 42 in 27 chronically infected CF patients electively treated with 14 days of intravenous antibiotic. To analyze sputum samples, we used flowcytometry to count PMNs and colorimetric assays to estimate lactate and glucose.ResultsNo changes in levels of PMNs, glucose and lactate were detected in sputum during the antibiotic treatment. Sputum PMNs were positively associated with both glucose (log coefficient = 0.20, p = 0.01) and L-lactate (log coefficient = 0.34, pConclusionsIn CF sputum PMNs, glucose and lactate were unchanged during elective antibiotic treatment. However, sputum PMNs were associated with both sputum glucose and sputum lactate. Surprisingly, hyperglycemia seemed to be associated with less PMNs infiltration and less glucose in CF sputum

A study on African vernacular mosque: A lesson from tradition

Mosques as a symbol of Islamic cities have a significant place in Islamic Architecture and it prompts architects to create admirable, magnificent buildings. While several studies have done on features and prototypes in this field but mainly it leaded to exaggerate dominance of dome as inseparable component of mosques. Although dome construction is costly, it is not that much adaptable to different climates and even it is not a good culture indicator of different countries, still there is a strong insist on presence of dome in mosques everywhere. This paper aims to study African mosque example which deeply relied on vernacular architecture. Various styles of design in Mali as case study investigated in terms of material, design concept, to arrive at concrete results

Increased bactericidal activity of colistin on <i>Pseudomonas aeruginosa </i>biofilms in anaerobic conditions

Tolerance towards antibiotics of Pseudomonas aeruginosa biofilms is recognized as a major cause of therapeutic failure of chronic lung infection in cystic fibrosis (CF) patients. This lung infection is characterized by antibiotic-tolerant biofilms in mucus with zones of O(2) depletion mainly due to polymorphonuclear leukocytic activity. In contrast to the main types of bactericidal antibiotics, it has not been possible to establish an association between the bactericidal effects of colistin and the production of detectable levels of OH ˙ on several strains of planktonic P. aeruginosa. Therefore, we propose that production of OH ˙ may not contribute significantly to the bactericidal activity of colistin on P. aeruginosa biofilm. Thus, we investigated the effect of colistin treatment on biofilm of wild-type PAO1, a catalase-deficient mutant (ΔkatA) and a colistin-resistant CF isolate cultured in microtiter plates in normoxic- or anoxic atmosphere with 1 mM nitrate. The killing of bacteria during colistin treatment was measured by CFU counts, and the OH⋅ formation was measured by 3(′)-(p-hydroxylphenyl fluorescein) fluorescein (HPF) fluorescence. Validation of the assay was done by hydrogen peroxide treatment. OH⋅ formation was undetectable in aerobic PAO1 biofilms during 3 h of colistin treatment. Interestingly, we demonstrate increased susceptibility of P. aeruginosa biofilms towards colistin during anaerobic conditions. In fact, the maximum enhancement of killing by anaerobic conditions exceeded 2 logs using 4 mg L(−1) of colistin compared to killing at aerobic conditions