Novel Quorum Quenching YtnP Lactonase From Bacillus paralicheniformis Reduces Pseudomonas aeruginosa Virulence and Increases Antibiotic Efficacy in vivo

Bacterial infections have become increasingly difficult to treat due to the occurrence of antibiotic-resistant strains. A promising strategy to increase the efficacy of therapy is to combine antibacterials with agents that decrease pathogen virulence via the modulation of the quorum sensing (QS). Lactonases inhibit acylated homoserine lactone (AHL)-mediated QS in Gram-negative bacteria, including the leading nosocomial pathogen Pseudomonas aeruginosa. Here we describe the characteristics of heterologously expressed YtnP lactonase from Bacillus paralicheniformis ZP1 (YtnP-ZP1) isolated from agricultural soil using the culture enrichment method. Purified YtnP-ZP1 hydrolyzed different AHLs with preference to substrates with long acyl residues as evaluated in assays with biosensors and HPLC. The enzyme showed good thermostability and activity in a wide temperature range. YtnP-ZP1 in 50 μg mL–1 concentration reduced the amount of P. aeruginosa-produced long-chain AHLs by 85%, while it hydrolyzed 50% of short-chain AHLs. Incubation of P. aeruginosa PAO1 with YtnP-ZP1 reduced its swarming motility and elastolytic activity without bactericidal effect. YtnP-ZP1 caused the inhibition of biofilm formation and disintegration of mature biofilms in P. aeruginosa PAO1 and multiresistant clinical strain BR5H that was visualized by crystal violet staining. The treatment with YtnP-ZP1 in concentrations higher than 25 μg mL–1 improved the survival of P. aeruginosa PAO1-infected zebrafish (Danio rerio), rescuing 80% of embryos, while in combination with tobramycin or gentamicin survival rate increased to 100%. The treatment of P. aeruginosa PAO1 biofilms on infected zebrafish tail wounds with 50 μg mL–1 YtnP-ZP1 and 2 × MIC tobramycin led to infection clearing in 2 days. The extensive toxicity studies proved YtnP-ZP1 was non-toxic to human cells and zebrafish. In conclusion, novel YtnP-ZP1 lactonase with its effective anti-virulence activity could be used to increase the efficacy of clinically approved antibiotics in clearing both systemic and biofilm-associated P. aeruginosa infections

Concentration of C-reactive protein, magnesium and calcium in children with acute bronchoconstriction before and after therapy with salbutamol

Introduction: In childhood, bronchoobstruction is mostly caused by respiratory viral infections. The aim of this study was to find out possible changes in serum concentration of magnesium and calcium (participants in bronchoconstriction), and concentration of C-reactive protein (marker of inammation) in children with moderate and severe bronchoconstriction, caused by viral respiratory infections. Materials and methods: The study included 32 children with acute bronchoconstriction caused by a viral respiratory infection. Inhalation of salbutamol was administered according to the severity of bronchoconstriction. Blood sampling was done on admission and the third day of salbutamol administration. Results: Therapy with salbutamol led to a relief of dyspnea within 36 hours, and symptoms of viral infection have relieved. During follow-up period, magnesium concentration was higher in children with moderate (but not in severe) bronchoconstriction than in healthy children, with consequently higher magnesium to calcium ratio. Concentration of C-reactive protein decreased spontaneously by gradual disappearance of signs and symptoms of viral infection. Conclusion: Determination of serum magnesium and calcium concentrations and determination of their ratio are not sufficient enough to follow-up on effects of therapy. Additional studies of ionized forms of magnesium and calcium, their intracellular content, as well as concentration in exhaled breath condensate are needed

Baclofen-induced dyshidrosiform bullous pemphigoid in a paraplegic patient complicated with methicillin-resistant Staphylococcus aureus (mrsa) and urinary infection

Bullous pemphigoid (BP) is an autoimmune disorder which is usually chronic, with blistering that predominantly affects the skin and occasionally the mucosa, and which includes several different types. One of them is a very rare dyshidrosiform type which is localized on the hands and feet with small or large blisters on the palmoplantar surfaces. BP resulting from a drug reaction is a relatively rare occurrence, and so far more than 50 different medications have been identified as triggers. The aim of this article was to present the case of a paraplegic patient who developed this rare dyshidrosiform type of BP while he was being neurologically treated with baclofen. In spite of therapy with systemic and topical corticosteroids and other measures, successful treatment was achieved only after eliminating baclofen from the patient’s regimen. His general state of health was seriously endangered due to nasal and skin methicillin-resistant Staphylococcus aureus (MRSA), urinary infection, and oral mycosis (soor), and he was at high risk of sepsis and a fatal outcome. Through our efforts, however, we managed to achieve an excellent outcome. According to our knowledge, this was the first case of baclofen-induced dyshidrosiform BP. </p

Epidemiological surveillance of Pertussis: the experience of Argentina and its relevance for the other countries in the region

[email protected] al editorRevisión por pare

Prevalencia y factores asociados a infección por Bordetella Pertussis en niños menores de 5 años con infección respiratoria aguda (IRA) en un hospital de Lima

Background: Pertussis diagnosis may go unrecognized when other pathogens, such as respiratory syncytial virus (RSV) circulate. Methods: A prospective cross-sectional study was conducted in Lima, Peru from January 2009 to September 2010. A total of 596 children under 5 years old admitted with clinical diagnoses of acute respiratory infections were test for B. pertussis and RSV detection by polymerase chain reaction (PCR). Results: The pertussis toxin and IS481 genes were detected in 19.12% (114/596) of the cases and the respiratory syncytial viruses (RSV-A and RSV-B) were identified in 17.28% (103/596) of patients. Infants under 3 months old were the most frequently affected by this pathogens in 43% (49/114) and 35.9% (37/103) respectively. An increase of B. pertussis was observed from February to March and from October to November with a Seasonal index between 1.32-1.51 and 1.24-3.5 respectively. Conclusions: Epidemiologic surveillance for B. pertussis is essential in Peru, especially in children that could most benefit from the vaccine. B. pertussis should be suspected in infants hospitalized for acute respiratory symptoms for early treatment and prevent complications.Tesi