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

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

Phosphofructokinases from extremely thermophilic microorganisms

The distribution of phosphofructokinase (PFK) phosphoryl donor subtypes [ATP-, ADP- and pyrophosphate (PPᵢ)] in the deeply rooted phylogenetic lineages of thermophiles is of interest with respect to the evolution of PFK activity and of the Embden-Meyerhof (EM) pathway. To gain additional insight into the understanding of this key enzyme in the central metabolism within the three domains of life, PFKs with different phosphoryl donor specificities were studied from some extremely thermophilic bacteria, archaea and non-thermophilic bacteria. Results from a survey of species from the order Spirochaetales showed that all of the tested species of Spirochaeta, both thermophilic and mesophilic species/strains, possessed a PPᵢ-dependent PFK (PPᵢ-PFK) activity. However, ATP dependent-PFK activities were found to be predominant in some strains of Leptospira and Treponema. Overall, the results suggest that the presence of a PPᵢ-PFK might be a reliable phenotypic marker for the genus Spirochaeta and that there are some potentially interesting differences in how the catabolism of saccharides is controlled among members of genera within the Spirochaetales. The PPᵢ-PFK from an extremely thermophilic bacterium Dictyoglomus thermophilum Rt46 B.1 has been purified and characterised. Biochemical studies with the Dictyoglomus native enzyme showed that this enzyme possesses some properties that are similar to other bacterial PPᵢ-PFKs. The enzyme is homodimeric, non-allosteric and possesses an acidic pH optimum for the forward reaction and a neutral to slightly alkaline optimum for the reverse reaction. The enzyme requires Mg²⁺ for optimal activity and has significant activity with tripolyphosphate (PPPᵢ) and polyphosphate (polyP, n=15±3). The Dictyoglomus enzyme is extremely sensitive to Cu²⁺. The Dictyoglomus PPᵢ-PFK-encoding gene (pfp) was also sequenced, cloned and the enzyme expressed in Escherichia coli. The full-length sequence of the pfp gene was obtained using degenerate PCR and inverse-PCR. Sequence analysis and a phylogenetic comparison suggest that the Dictyoglomus PPᵢ-PFK represents an ancient lineage and is closely related to those PPᵢPFKѕ from the archaeal Thermoproteus tenax, bacterial Mycobacterium tuberculosis and Amycolatopsis methanolica, and the ATP-PFK from Streptomyces coelicolor, all of which belong to group III PFKѕ. A biochemical comparison between the Dictyoglomus native and recombinant enzymes demonstrated that they possessed a high degree of similarity in most of properties examined, e.g. the optimal pH values and Mg²⁺ concentration for activity, lack of allosteric response to metabolites, thermostability, most kinetic parameters and extreme sensitivity to Cu²⁺. An ATP-PFK from the hyperthermophilic crenarchaeon Desulfurococcus amylolyticus was also purified to homogeneity and characterised. The enzyme was confirmed as an ATP-dependent enzyme possessing no activity with either ADP or PPᵢ. The Desulfarococcus enzyme was not significantly affected by traditional allosteric modulators, e.g. phosphoenolpyruvate (PEP), citrate, succinate or fructose- 2,6-bisphosphate (F-2,6-P₂). This enzyme similar to what was found for the Dictyoglomus PFK is also extremely sensitive to Cu²⁺. Two genes from the hyperthermophilic bacterium Thermotoga maritima, one encoding a PPᵢ- PFK and the other an ATP-PFK, were cloned, expressed and characterised. Both enzymes were shown to be extremely thermostable, activated by KC1 and strongly inhibited by Cu²⁺ and Zn²⁺. The PPᵢ-PFK enzyme is indicated to be a non-allosteric homodimer which catalyses a near-reversible reaction. Significantly, the apparent Kₘ values for the phosphoryl donors PPᵢ, PPPᵢ and polyP (n=15±3) for the forward reaction were 67 μM, 10 μM and 3.8 μM respectively, and thus the enzyme might operate in vivo as a polyP-dependent PFK. The ATP-PFK exhibited significant activity with other nucleotide triphosphates, GTP (42% of control activity with ATP), UTP (14%), CTP (13%) and TTP (10%), but its activity was not significantly affected by common allosteric effectors, i.e. PEP, although it was partially inhibited by citrate. Surprisingly, the ATP-PFK was strongly inhibited by PPᵢ, PPPᵢ and polyP. The inhibition by PPᵢ could be partially relieved by nucleotide diphosphates including ADP, GDP, TDP and UDP. The T. maritima ATP-PFK is thus likely to be modulated by PPᵢ and/or polyP which would represent a novel mechanism for controlling glycolytic flux. Taken together, the data suggests that the distribution, subtypes and regulatory mechanisms of PFK in the control of the EM pathway in extremely thermophilic organisms are much more complex than we expected. As originally intended, the results from this work has provided additional insights into the understanding of the evolution of this key enzyme in glycolysis

Flavin Mononucleotide-Binding Flavoprotein Family in the Domain Archaea

The protein (AfpA, for archaeoflavoprotein) encoded by AF1518 in the genome of Archaeoglobus fulgidus was produced in Escherichia coli and characterized. AfpA was found to be a homodimer with a native molecular mass of 43 kDa and containing two noncovalently bound flavin mononucleotides (FMNs). The cell extract of A. fulgidus catalyzed the CO-dependent reduction of AfpA that was stimulated by the addition of ferredoxin. Ferredoxin was found to be a direct electron donor to purified AfpA, whereas rubredoxin was unable to substitute. Neither NADH nor NADPH was an electron donor. Ferricyanide, 2,6-dichlorophenolindophenol, several quinones, ferric citrate, bovine cytochrome c, and O(2) accepted electrons from reduced AfpA, whereas coenzyme F(420) did not. The rate of cytochrome c reduction was enhanced in the presence of O(2) suggesting that superoxide is a product of the interaction of reduced AfpA with O(2). Although AF1518 was previously annotated as encoding a decarboxylase involved in coenzyme A biosynthesis, the results establish that AfpA is an electron carrier protein with ferredoxin as the physiological electron donor. The genomes of several diverse Archaea contained afpA homologs clustered with open reading frames annotated as homologs of genes encoding reductases involved in the oxidative stress response of anaerobes from the domain Bacteria. A potential role for AfpA in coupling electron flow from ferredoxin to the putative reductases is discussed. A search of the databases suggests that AfpA is the prototype of a previously unrecognized flavoprotein family unique to the domain Archaea for which the name archaeoflavoprotein is proposed

OmcF, a Putative c-Type Monoheme Outer Membrane Cytochrome Required for the Expression of Other Outer Membrane Cytochromes in Geobacter sulfurreducens

Outer membrane cytochromes are often proposed as likely agents for electron transfer to extracellular electron acceptors, such as Fe(III). The omcF gene in the dissimilatory Fe(III)-reducing microorganism Geobacter sulfurreducens is predicted to code for a small outer membrane monoheme c-type cytochrome. An OmcF-deficient strain was constructed, and its ability to reduce and grow on Fe(III) citrate was found to be impaired. Following a prolonged lag phase (150 h), the OmcF-deficient strain developed the ability to grow in Fe(III) citrate medium with doubling times and yields that were ca. 145% and 70% of those of the wild type, respectively. Comparison of the c-type cytochrome contents of outer membrane-enriched fractions prepared from wild-type and OmcF-deficient cultures confirmed the outer membrane association of OmcF and revealed multiple changes in the cytochrome content of the OmcF-deficient strain. These changes included loss of expression of two previously characterized outer membrane cytochromes, OmcB and OmcC, and overexpression of a third previously characterized outer membrane cytochrome, OmcS, during growth on Fe(III) citrate. The omcB and omcC transcripts could not be detected in the OmcF-deficient mutant by either reverse transcriptase PCR or Northern blot analyses. Expression of the omcF gene in trans restored both the capacity of the OmcF-deficient mutant to reduce Fe(III) and wild-type levels of omcB and omcC mRNA and protein. Thus, elimination of OmcF may impair Fe(III) reduction by influencing expression of OmcB, which has previously been demonstrated to play a critical role in Fe(III) reduction