Nitrosative stress defences of the enterohepatic pathogenic bacterium Helicobacter pullorum

Helicobacter pullorum is an avian bacterium that causes gastroenteritis, intestinal bowel and hepatobiliary diseases in humans. Although H. pullorum has been shown to activate the mammalian innate immunity with release of nitric oxide (NO), the proteins that afford protection against NO and reactive nitrogen species (RNS) remain unknown. Here several protein candidates of H. pullorum, namely a truncated (TrHb) and a single domain haemoglobin (SdHb), and three peroxiredoxin-like proteins (Prx1, Prx2 and Prx3) were investigated. We report that the two haemoglobin genes are induced by RNS, and that SdHb confers resistance to nitrosative stress both in vitro and in macrophages. For peroxiredoxins, the prx2 and prx3 expression is enhanced by peroxynitrite and hydrogen peroxide, respectively. Mutation of prx1 does not alter the resistance to these stresses, while the single ∆prx2 and double ∆prx1∆prx2 mutants have decreased viability. To corroborate the physiological data, the biochemical analysis of the five recombinant enzymes was done, namely by stopped-flow spectrophotometry. It is shown that H. pullorum SdHb reacts with NO much more quickly than TrHb, and that the three Prxs react promptly with peroxynitrite, Prx3 displaying the highest reactivity. Altogether, the results unveil SdHb and Prx3 as major protective systems of H. pullorum against nitrosative stress

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

The bactericidal activity of carbon monoxide-releasing molecules against Helicobacter pylori.

Helicobacter pylori is a pathogen that establishes long life infections responsible for chronic gastric ulcer diseases and a proved risk factor for gastric carcinoma. The therapeutic properties of carbon-monoxide releasing molecules (CORMs) led us to investigate their effect on H. pylori. We show that H. pylori 26695 is susceptible to two widely used CORMs, namely CORM-2 and CORM-3. Also, several H. pylori clinical isolates were killed by CORM-2, including those resistant to metronidazole. Moreover, sub-lethal doses of CORM-2 combined with metronidazole, amoxicillin and clarithromycin was found to potentiate the effect of the antibiotics. We further demonstrate that the mechanisms underpinning the antimicrobial effect of CORMs involve the inhibition of H. pylori respiration and urease activity. In vivo studies done in key cells of the innate immune system, such as macrophages, showed that CORM-2, either alone or when combined with metronidazole, strongly reduces the ability of H. pylori to infect animal cells. Hence, CORMs have the potential to kill antibiotic resistant strains of H. pylori

Effect of combined metronidazole and CORM-2 treatment on <i>H. pylori</i> viability.

<p>Cell viability of <i>H. pylori</i> 26695 left untreated (black) and exposed to iCORM-2 (dark grey), 100 mg/L CORM-2 (white), 1.5 mg/L metronidazole (light grey), 1.5 mg/L metronidazole plus 200 mg/L iCORM-2 (light grey, diagonal strips) and 1.5 mg/L metronidazole plus 100 mg/L CORM-2 (light grey, horizontal strips). The number of viable cells were determined for four independent cultures and are expressed as means ± SE. ***p<0.001 (Two-way ANOVA and Bonferroni test).</p

CORM-2 lowers MIC and MBC of metronidazole for <i>H. pylori</i> clinical isolates.

<p>(<b>A</b>) MIC of metronidazole determined for each <i>H pylori</i> clinical isolate in the absence (grey) and in the presence of CORM-2 (black). Strains 5846 and 5587 were treated 50 mg/CORM-2, strains 5611 and 4574 exposed to 100 mg/L CORM-2, and strains 5599 and 4597 submitted to 150 mg/L CORM-2. (<b>B</b>) MBC of metronidazole for each <i>H pylori</i> clinical isolates, in the absence (grey) and in the presence of CORM-2 (black). Strains 5846 and 5587 were treated 200 mg/CORM-2, and strains 5611, 4574, 5599 and 4597 exposed to 150 mg/L CORM-2. For each strain, metronidazole was combined with a CORM-2 concentration below the MIC/MBC of the CORM-2 alone. In all cases, values representing the median of five biological samples were significantly different (p<0.05 in Mann Whitney <i>t</i> test).</p

Effect of CORM-2 on MIC/MBC values of metronidazole, amoxicillin and clarithromycin for <i>H. pylori</i>.

<p>MICs (<b>A</b>) and MBCs (<b>B</b>) of metronidazole (MTZ), amoxicillin (AMX) and clarithromycin (CH) against <i>H. pylori</i> 26995 determined in the absence (black) and in the presence of 100 mg/L (dark grey) and 150 mg/L CORM-2 (light grey). Results represent the median of five biological samples and are significantly different in all cases (p<0.05 in Mann Whitney <i>t</i> test).</p

CORM-2 inhibits urease activity of <i>H. pylori.</i>

<p>(<b>A</b>) Urease activity was measured in <i>H. pylori</i> cells left untreated (black), treated for 15 h with 400 mg/L iCORM-2 (grey) and 200 mg/L CORM-2 (white). The results represent the average of three biological samples performed in duplicate, and error bars represent SE. ***p<0.001, ns - non significant (One-way ANOVA and Bonferroni test). (<b>B</b>) Urease activity of <i>H. pylori</i> cell suspensions treated, for 15 min, with CORM-2 (0, 2.5, 5, 12.5, 25, 50, 100 and 200 mg/L). The results are the average of five biological samples and error bars represent SE.</p