Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Protecting the gut against Clostridium difficile: A role for Keratinocyte growth factor

Clostridium difficle (Cdiff) infection (CDI) causes severe colitis via its toxins: toxin A and toxin B (TcdAB), inducing barrier disruption, inflammation and cell death. Current treatments are failing and the need to search for new targets is urgent. Several host factors have shown to modulate CDI in animals and patients. Intestinal growth factors are a major part of the mucosal host response in the gut. Among them, keratinocyte growth factor (KGF) has been shown to be protective in many colitis models. In this thesis, the protective role of KGF was demonstrated against Cdiff toxin injury. In vitro, KGF protected Caco-2 cells from barrier disruption and cell death induced by TcdAB. Exogenous KGF administration protected mice from acute intestinal toxin damage. Interestingly, KGF deletion did not impact the acute toxin-induced colitis in mice; however, endogenous KGF was essential for normal recovery from TcdAB-induced colitis as KGF−/− mice demonstrated impaired recovery after 24-48 hours post TcdAB exposure. Findings from this study may lead to identifying a cause for the variability in clinical response among patients with CDI as well as new therapeutic targets for this devastating disease.2 year

The P2Y6 receptor mediates Clostridium difficile toxin-induced CXCL8/IL-8 production and intestinal epithelial barrier dysfunction.

C. difficile is a Gram-positive spore-forming anaerobic bacterium that is the leading cause of nosocomial diarrhea in the developed world. The pathogenesis of C. difficile infections (CDI) is driven by toxin A (TcdA) and toxin B (TcdB), secreted factors that trigger the release of inflammatory mediators and contribute to disruption of the intestinal epithelial barrier. Neutrophils play a key role in the inflammatory response and the induction of pseudomembranous colitis in CDI. TcdA and TcdB alter cytoskeletal signaling and trigger the release of CXCL8/IL-8, a potent neutrophil chemoattractant, from intestinal epithelial cells; however, little is known about the surface receptor(s) that mediate these events. In the current study, we sought to assess whether toxin-induced CXCL8/IL-8 release and barrier dysfunction are driven by the activation of the P2Y6 receptor following the release of UDP, a danger signal, from intoxicated Caco-2 cells. Caco-2 cells express a functional P2Y6 receptor and release measurable amounts of UDP upon exposure to TcdA/B. Toxin-induced CXCL8/IL-8 production and release were attenuated in the presence of a selective P2Y6 inhibitor (MRS2578). This was associated with inhibition of TcdA/B-induced activation of NFκB. Blockade of the P2Y6 receptor also attenuated toxin-induced barrier dysfunction in polarized Caco-2 cells. Lastly, pretreating mice with the P2Y6 receptor antagonists (MSR2578) attenuated TcdA/B-induced inflammation and intestinal permeability in an intrarectal toxin exposure model. Taken together these data outline a novel role for the P2Y6 receptor in the induction of CXCL8/IL-8 production and barrier dysfunction in response to C. difficile toxin exposure and may provide a new therapeutic target for the treatment of CDI

The Effect of the Digital Manufacturing Technique, Preparation Taper, and Cement Type on the Retention of Aged Anterior Provisional Crowns: An In Vitro Study

A well-made provisional fixed prosthesis must present as a preview of the future prosthesis and may also augment the health of the abutments and periodontium. Provisional restorations have been prepared chairside with polymethyl methacrylate (PMMA) since time immemorial. CAD/CAM additive and subtractive technologies have revolutionized the fabrication of interim restorations in dental clinics. The current literature lacks substantial data about retention of provisional crowns manufactured using Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) additive and subtractive techniques with various temporary cements. This in vitro study aims to assess and compare the retention of temporary/provisional anterior crowns based on the combined effect of different digital manufacturing techniques, preparation tapers, and the temporary cements used for cementation. Two maxillary right central incisor typodont teeth were prepared to receive all-ceramic crowns, one with a 10-degree taper and the other with a 20-degree taper. Forty 3D-printed working models with the 10&deg; taper and forty working models with the 20&deg; taper were prepared to receive the temporary crowns. Forty temporary crowns were 3D-printed and forty crowns were milled (20 from each taper group). Kerr Temp-Bond NE conventional cement and Kerr Temp-Bond clear cement were used for cementation in the two groups. The number of samples per test group was 10. All samples were thermocycled and subjected to a universal testing machine to measure the pull-off force until retention loss (N) under tension with a crosshead speed of 5 mm/min. The pull-off force was highest for group 8, i.e., 3D-printed crowns with a 20&deg; taper and cemented with Kerr Temp-Bond clear cement, followed by groups 6, 7, 4, 5, 3, and 2. Group 1, i.e., milled crowns with 10&deg; taper cemented with Kerr Temp-Bond NE conventional cement, exhibited the lowest pull-off retentive force. The clinical selection of long-term provisional crowns fabricated using 3D-printing technology, prepared with 10&deg; or 20&deg; tapers, and cemented with clear cement, is the most favorable in terms of the retention of provisional crowns. 3D-printed provisional crowns can be used as an alternative to conventional and CAD/CAM-milled crowns for long-term provisionalization

The Effect of the Digital Manufacturing Technique, Preparation Taper, and Cement Type on the Retention of Aged Anterior Provisional Crowns: An In Vitro Study

A well-made provisional fixed prosthesis must present as a preview of the future prosthesis and may also augment the health of the abutments and periodontium. Provisional restorations have been prepared chairside with polymethyl methacrylate (PMMA) since time immemorial. CAD/CAM additive and subtractive technologies have revolutionized the fabrication of interim restorations in dental clinics. The current literature lacks substantial data about retention of provisional crowns manufactured using Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) additive and subtractive techniques with various temporary cements. This in vitro study aims to assess and compare the retention of temporary/provisional anterior crowns based on the combined effect of different digital manufacturing techniques, preparation tapers, and the temporary cements used for cementation. Two maxillary right central incisor typodont teeth were prepared to receive all-ceramic crowns, one with a 10-degree taper and the other with a 20-degree taper. Forty 3D-printed working models with the 10° taper and forty working models with the 20° taper were prepared to receive the temporary crowns. Forty temporary crowns were 3D-printed and forty crowns were milled (20 from each taper group). Kerr Temp-Bond NE conventional cement and Kerr Temp-Bond clear cement were used for cementation in the two groups. The number of samples per test group was 10. All samples were thermocycled and subjected to a universal testing machine to measure the pull-off force until retention loss (N) under tension with a crosshead speed of 5 mm/min. The pull-off force was highest for group 8, i.e., 3D-printed crowns with a 20° taper and cemented with Kerr Temp-Bond clear cement, followed by groups 6, 7, 4, 5, 3, and 2. Group 1, i.e., milled crowns with 10° taper cemented with Kerr Temp-Bond NE conventional cement, exhibited the lowest pull-off retentive force. The clinical selection of long-term provisional crowns fabricated using 3D-printing technology, prepared with 10° or 20° tapers, and cemented with clear cement, is the most favorable in terms of the retention of provisional crowns. 3D-printed provisional crowns can be used as an alternative to conventional and CAD/CAM-milled crowns for long-term provisionalization

TcdB, but not TcdA triggers CXCL8/IL-8 production and release from Caco-2 cells in a manner dependent on extracellular nucleotides and the P2Y₆ receptor.

<p>(A) CXCL8/IL-8 release from Caco-2 cells treated with purified TcdA or TcdB (16 hr). N = 5; * denotes p<0.05 compared to TcdA. (B) TcdB, but not TcdA, treatment of Caco-2 cells increases cell death as assessed by LDH release. N = 5; * denotes p<0.05 compared to TcdA. TcdB-induced CXCL8/IL-8 release is significantly reduced by (C) MRS2578 (10 μM) and (D) co-treatment with apyrase (20 u/mL). N = 5; * denotes p<0.05 compared to no treatment; # denotes p<0.05 compared to all groups. </p

<i>C. difficile</i> TcdA/B triggers the release of UDP from Caco-2 cells that express a functional P2Y₆ receptor.

<p>(A) Western blot analysis of lysates reveals the expression of the P2Y₆ receptor in differentiated Caco-2 cells and PMA-differentiated THP-1 macrophages (included as positive control). (B) Stimulation of the Caco-2 cells with the selective P2Y₆ receptor agonist 5-OMe-UDP (1 μM) increases intracellular calcium concentrations as assessed by fluorescence imaging. (B-i) Pseudocolour images of Caco-2 cells before and after 5-OMe-UDP treatment. (B-ii) Representative traces of individual cells challenged with 5-OMe-UDP. (B-iii) The mean of the 5-OMe-UDP-induced calcium responses (n=46; grey denotes the standard error of the mean). (C) P2Y₆ receptor agonist 5-OMe-UDP triggers CXCL8/IL-8 release from Caco-2 cells, an effect that blocked by the potent P2Y₆ receptor antagonist MRS2578. N = 6; * denotes p<0.05 compared to control; # denotes p<0.05 compared to vehicle; % denotes p<0.05 compared to vehicle and 1 μM MRS 2578. (D) TcdA/B triggers the release of UDP as assessed by HPLC. i – control treated culture supernatant; ii – UDP-spiked control culture supernatant (100 μM UDP); iii – TcdA/B-spiked control culture supernatant (10 μg/mL); iv – TcdA/B-treated cell culture supernatant (10 μg/mL; 16 hr). (E) Summary data from HPLC measurement of TcdA/B-induced UDP release. N=5; * denotes p<0.05.</p

TcdA/B-induced CXCL8/IL-8 production from Caco-2 IECs involves the NFκB activation, an effect that is inhibited by pharmacological blockade of the P2Y₆ receptor by MRS2578.

<p>(A) TcdA/B-induced CXCL8/IL-8 release is inhibited by pretreatment with the selective NFκB pathway inhibitor BAY 11-7085 (20 μM). N=6; ** denotes p<0.005 compared to vehicle-treated TcdA/B stimulated cells (10 μg/mL). (B) Representative western blot for phosphorylated p65 (P-p65) in lysates from TcdA/B (10 μg/mL) stimulated Caco-2 IECs over the course of 60 min in the presence of the P2Y₆ antagonist MRS2578 (10 μM) or vehicle control (DMSO). (C) The summarized western blot data for P-p65 expressed as a percentage of the total p65. N = 4, *, denotes p<0.05 compared to time 0 min; # denotes p<0.05 compared to respective vehicle control (DMSO). </p

TcdA/B-induced intestinal inflammation and permeability are attenuated by inhibiting the P2y₆ receptor <i>in</i><i>vivo</i>.

<p>(A) Intrarectal instillation of TcdA/B (50 μg/100 μL for 4 hrs) triggers a significant increase in colonic tissue myeloperoxidase (MPO), an effect that is significantly reduced by pretreating mice with the P2Y₆ inhibitor MRS 2578 (100 μL of 10 μM; in PBS via intrarectal instillation). N = 6/group; * denotes p<0.05 compared to PBS vehicle groups; # denotes p<0.05 compared to TcdA/B treatment with vehicle (DMSO). (B) Pretreating mice with MRS 2578 (100 μL of 10 μM; in PBS via intrarectal instillation) inhibits TcdA/B-induced increases in permeability as assessed by FITC-flux from the colonic lumen in to the serum. N = 6/group; * denotes p<0.05 compared to PBS vehicle groups; # denotes p<0.05 compared to TcdA/B treatment with vehicle (DMSO). (C) Pretreating mice with MRS 2578 reduces the histological inflammatory score and the (D) percentage of the colonic tissue section exhibiting architectural changes (% architecture change). N = 12 sections/group; * denotes P<0.05 compared to vehicle pretreatment. (E) Representative colonic sections stained with hematoxylin and eosin from mice treated with vehicle, MRS2578 alone, vehicle + TcdA/B and MRS2578 + TcdA/B; N = 6/group.</p