Structural Patterns Enhancing the Antibacterial Activity of Metallacarborane-Based Antibiotics

Healthcare systems heavily rely on antibiotics to treat bacterial infections, but the widespread presence of multidrug-resistant bacteria puts this strategy in danger. Novel drugs capable of overcoming current resistances are needed if our ability to treat bacterial infections is to be maintained. Boron clusters offer a valuable possibility to create a new class of antibiotics and expand the chemical space of antibiotics beyond conventional carbon-based molecules. In this work, we identified two promising structural patterns providing cobalta bis(dicarbollide)(COSAN)-based compounds with potent and selective activity toward Staphylococcus aureus (including clinical strains): introduction of the α-amino acid amide and addition of iodine directly to the metallacarborane cage. Furthermore, we found that proper hydrophilic-lipophilic balance is crucial for the selective activity of the tested compounds toward S. aureus over mammalian cells. The patterns proposed in this paper can be useful in the development of metallacarborane-based antibiotics with potent antibacterial properties and low cytotoxicity.

Long-term survival following postoperative myocardial infraction after coronary artery bypass surgery

Background

Postoperative myocardial infraction (MI) is a serious complication among patients undergoing Coronary Artery Bypass Grafting (CABG). Data on the impact of postoperative MI on patients undergoing CABG, specifically with respect to their long term outcomes are sparse.

Methods

We retrospectively analyzed all patients who underwent isolated CABG between January 2014 and December 2016 and identified those who fulfilled the definition of the type 5MI following CABG according to the Fourth Universal Definition of Myocardial Infarction.

Results

A total of 4,642 CABG patients were identified, of whom 141 (3.04%) were diagnosed with postoperative MI. The mean follow-up time was 5.1±2.07 years (range, 4.4–6.9 years). Postoperative MI was more common in patients with recent acute coronary syndrome, when compared to stable angina (22.8% vs. 31.9%; P=0.011) and in those with non-elective versus planned surgery (28.4% vs. 18.4%; P=0.003). Postoperative MI after CABG was associated with an increased rate of postoperative complications, including cardiac tamponade and re exploration for bleeding. Mortality after postoperative MI was higher at short-term follow-up (up to one year) and long-term follow-up (up to five years). The risk factors for postoperative MI after CABG were incomplete revascularization (IR) [OR (95% CI): 2.25 (1.59–3.12), P=0.001], non-elective surgery [OR (95% CI): 1.68 (1.10–2.54), P=0.015] and female gender [OR (95% CI): 1.48 (1.01–2.18), P=0.045].

Conclusions

PMI after CABG is associated with reduced short- and long-term survival. The main risk factors for postoperative MI are IR, female gender, and non-elective surgery.

Benefits of Usage of Immobilized Silver Nanoparticles as Pseudomonas aeruginosa Antibiofilm Factors

The aim of this study was to assess the beneficial inhibitory effect of silver nanoparticles immobilized on SiO2 or TiO2 on biofilm formation by Pseudomonas aeruginosa-one of the most dangerous pathogens isolated from urine and bronchoalveolar lavage fluid of patients hospitalized in intensive care units. Pure and silver doped nanoparticles of SiO2 and TiO2 were prepared using a novel modified sol-gel method. Ten clinical strains of P. aeruginosa and the reference PAO1 strain were used. The minimal inhibitory concentration (MIC) was determined by the broth microdilution method. The minimal biofilm inhibitory concentration (MBIC) and biofilm formation were assessed by colorimetric assay. Bacterial enumeration was used to assess the viability of bacteria in the biofilm. Silver nanoparticles immobilized on the SiO2 and TiO2 indicated high antibacterial efficacy against P. aeruginosa planktonic and biofilm cultures. TiO2/Ag0 showed a better bactericidal effect than SiO2/Ag0. Our results indicate that the inorganic compounds (SiO2, TiO2) after nanotechnological modification may be successfully used as antibacterial agents against multidrug-resistant P. aeruginosa strains.

Bilateral internal thoracic artery use in two-vessel disease does not increase the perioperative risk-A propensity score matched analysis

Background

Bilateral internal thoracic arteries (BITA) are uncommonly used in the every-day practice due to safety concerns and technical challenges with Y-grafts. We hypothesized that in-situ BITA use during coronary artery by-pass grafting (CABG) for two vessel disease is equally safe to standard strategy with left internal thoracic artery-left anterior descending artery revascularization and venous graft to other target vessels.

Methods

A propensity score matched analysis was used to compare elective on-pump CABG patients who received in-situ BITA (BITA-group), versus left internal thoracic artery graft to the left anterior descending artery plus vein (SITA-group). Primary end points were 30-days all-cause-mortality, major adverse cardiac events and incidents and deep sternal wound infections.

Results

A total of 50 matched pairs (c-statistics 0.769) were selected from patients operated on between January 2015 and April 2020 using BITA (n = 50) and SITA (n = 2170). There were no inter-group differences in demographics and basic clinical characteristics. The total operation time was longer in the BITA-group (4.0 vs 3.6 hours; p = 0.004). The rate of complete revascularization was similar, as was median aortic cross-clamp time, median extracorporeal circulation time, rate of re-explorations for bleeding, deep sternal wound infections or length of stay. One patient died in BITA group, 3 days after surgery, from a non-cardiac cause. After 36 months, the survival rate was 98% for BITA-group and 96% for controls (log-rank, p = 0.577).

Conclusions

In-situ use of BITA during coronary revascularization for two-vessel disease is as safe and effective, as use of single ITA and vein graft. In-situ strategy abolishes allows to avoid the technically demanding composite graft configuration.

Early postoperative hemodynamic instability after heart transplantation - incidence and metabolic indicators

Background

Primary graft dysfunction (PGD) is the main cause of death in the first 30 days after heart transplantation (HTX), accounting for approximately 40% of mortality. The study’s primary aim was to assess the incidence of PGD, following the International Society for Heart and Lung Transplantation consensus, and to compare it with the incidence of significant postoperative hypotension despite administration of high-dose inotropes and vasoconstrictors. The secondary aim of the study was to determine changes in biochemical markers that accompany the phenomenon.

Methods

Forty-five patients who underwent HTX between 2010 and 2015 were enrolled in this study, and detailed hemodynamic and metabolic data from the first 48 postoperative hours were collected and analyzed. Hemodynamic instability was defined as significant postoperative hypotension (mean arterial pressure (MAP) < 60 mmHg) combined with a high inotrope score (> 10). Data for long-term mortality were obtained from the population registration office.

Results

PGD incidence was relatively low (17.8%); however, hemodynamic instability was common (40%). Among unstable patients, MAP was insufficient for end-organ perfusion (51.4 ± 9.5 mmHg) but no decrease in left ventricular function was observed (cardiac index, 2.65 ± 0.6 l/min/m2; left ventricular ejection fraction, 52.9 ± 15.5%). Within this group, mean systemic vascular resistance index (961 ± 288 dyn*s*m2/cm5) was low despite receiving high doses of vasoactive agent (norepinephrine 0.21 (0.06-0.27) μg/kg/min during first 24 h postoperatively and 0.21 (0.01-0.27) μg/kg/min during next 24 h postoperatively). After HTX, serum lactate levels were initially significantly higher in patients with hemodynamic instability (p = 0.002); however, impaired lactate clearance was not observed (p = 0.366), and lactate levels normalized within the first 24 h postoperatively. Postoperative hemodynamic instability altered the long-term outcome and increased 5-year mortality after HTX (p = 0.034).

Conclusions

Hemodynamic instability is a more common phenomenon than PGD. Only early postoperative serum lactate levels correspond with hemodynamic instability following HTX. Postoperative hemodynamic instability is associated with poor long-term survival among HTX recipients.

The Impact of Graphite Oxide Nanocomposites on the Antibacterial Activity of Serum

Nanoparticles can interact with the complement system and modulate the inflammatory response. The effect of these interactions on the complement activity strongly depends on physicochemical properties of nanoparticles. The interactions of silver nanoparticles with serum proteins (particularly with the complement system components) have the potential to significantly affect the antibacterial activity of serum, with serious implications for human health. The aim of the study was to assess the influence of graphite oxide (GO) nanocomposites (GO, GO-PcZr(Lys)2-Ag, GO-Ag, GO-PcZr(Lys)2) on the antibacterial activity of normal human serum (NHS), serum activity against bacteria isolated from alveoli treated with nanocomposites, and nanocomposite sensitivity of bacteria exposed to serum in vitro (using normal human serum). Additionally, the in vivo cytotoxic effect of the GO compounds was determined with application of a Galleria mellonella larvae model. GO-PcZr(Lys)2, without IR irradiation enhance the antimicrobial efficacy of the human serum. IR irradiation enhances bactericidal activity of serum in the case of the GO-PcZr(Lys)2-Ag sample. Bacteria exposed to nanocomposites become more sensitive to the action of serum. Bacteria exposed to serum become more sensitive to the GO-Ag sample. None of the tested GO nanocomposites displayed a cytotoxicity towards larvae.

Protocol of proceedings with Fusobacterium nucleatum and optimization of ABTS method for detection of reactive oxygen species

Aim: Characterization of the ability of Fusobacterium nucleatum DSM 15643 and DSM 20482 strains in the presence of Cu²⁺ and H₂O₂ to reactive oxygen species generation. Method: Spectrophotometric ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) method was used. Results: Determination of: MIC for Cu²⁺, H₂O₂ and ABTS; survivability of F. nucleatum under atmospheric oxygen exposure; the level and rate constants of free radicals production by the bacteria. Conclusion: F. nucleatum in the presence of Cu²⁺ and H₂O₂ is able to generate free radicals. Reactive oxygen species are produced mainly outside the bacterial cell, which suggests that outer membrane proteins may be involved in oxidative process.

Proteomics-based identification of orchid-associated bacteria colonizing the Epipactis albensis, E. helleborine and E. purpurata (Orchidaceae, Neottieae)

Using proteomics-based identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), we conducted the first analysis of the composition of endophytic bacteria isolated from different parts of selected Epipactis species, i.e. the buds, the inflorescences and the central part of the shoots, as well as the rhizomes. We identified aerobic and anaerobic bacteria, including such taxa as Bacillus spp., Clostridium spp., Pseudomonas spp. and Stenotrophomonas spp., which may be considered as promoting plant growth. Because most of the indicated bacteria genera belong to spore-producing taxa (spores allow bacterial symbionts to survive adverse conditions), we suggest that these bacteria species contribute to the adaptation of orchids to the environment. We found clear differences in the microbiome between investigated closely related taxa, i.e., Epipactis albensis, E. helleborine, E. purpurata and E. purpurata f. chlorophylla. Some of the analysed orchid species, i.e. E. albensis and E. purpurata co-occur in habitats, and their bacterial microbiomes differ from each other.

Comparison of Antibacterial Mode of Action of Silver Ions and Silver Nanoformulations With Different Physico-Chemical Properties: Experimental and Computational Studies

The aim of this study was to compare the antibacterial mode of action of silver ions (Ag⁺) and selected silver nanoformulations against E. coli strains (E. coli J53, Escherichia coli BW25113 and its derivatives: Δ ompA, Δ ompC, Δ ompF, Δ ompR, ompRG596AcusSG1130A, cusSG1130A). In this research we used various experimental methods and techniques such as determination of the minimal inhibitory concentration, flow cytometry, scanning electron microscopy, circular dichroism as well as computational methods of theoretical chemistry. Thanks to the processing of bacteria and silver samples (ions and nanoformulations), we were able to determine the bacterial sensitivity to silver samples, detect reactive oxygen species (ROS) in the bacterial cells, visualize the interaction of silver samples with the bacterial cells, and identify their interactions with proteins. Differences between the mode of action of silver ions and nanoformulations and the action of nanoformulations themselves were revealed. Based on the results of computational methods, we proposed an explanation of the differences in silver-outer protein interaction between silver ions and metallic silver; in general, the Ag⁰ complexes exhibit weaker interaction than Ag⁺ ones. Moreover, we identified two gutter-like areas of the inner layer of the ion channel: one more effective, with oxygen-rich side chains; and another one less effective, with nitrogen-rich side chains.

How Bacteria Change after Exposure to Silver Nanoformulations: Analysis of the Genome and Outer Membrane Proteome

OBJECTIVE

the main purpose of this work was to compare the genetic and phenotypic changes of E. coli treated with silver nanoformulations (E. coli BW25113 wt, E. coli BW25113 AgR, E. coli J53, E. coli ATCC 11229 wt, E. coli ATCC 11229 var. S2 and E. coli ATCC 11229 var. S7). Silver, as the metal with promising antibacterial properties, is currently widely used in medicine and the biomedical industry, in both ionic and nanoparticles forms. Silver nanoformulations are usually considered as one type of antibacterial agent, but their physical and chemical properties determine the way of interactions with the bacterial cell, the mode of action, and the bacterial cell response to silver.

METHODS

the changes in the bacterial genome, resulting from the treatment of bacteria with various silver nanoformulations, were verified by analyzing of genes (selected with mutfunc) and their conservative and non-conservative mutations selected with BLOSUM62. The phenotype was verified using an outer membrane proteome analysis (OMP isolation, 2-DE electrophoresis, and MS protein identification).

RESULTS

the variety of genetic and phenotypic changes in E. coli strains depends on the type of silver used for bacteria treatment. The most changes were identified in E. coli ATCC 11229 treated with silver nanoformulation signed as S2 (E. coli ATCC 11229 var. S2). We pinpointed 39 genes encoding proteins located in the outer membrane, 40 genes of their regulators, and 22 genes related to other outer membrane structures, such as flagellum, fimbria, lipopolysaccharide (LPS), or exopolysaccharide in this strain. Optical density of OmpC protein in E. coli electropherograms decreased after exposure to silver nanoformulation S7 (noticed in E. coli ATCC 11229 var. S7), and increased after treatment with the other silver nanoformulations (SNF) marked as S2 (noticed in E. coli ATCC 11229 var. S2). Increase of FliC protein optical density was identified in turn after Ag+ treatment (noticed in E.coli AgR).

CONCLUSION

the results show that silver nanoformulations (SNF) exerts a selective pressure on bacteria causing both conservative and non-conservative mutations. The proteomic approach revealed that the levels of some proteins have changed after treatment with appropriate SNF.

Prognostic role of perioperative acid-base disturbances on the risk of Clostridioides difficile infection in patients undergoing cardiac surgery

BACKGROUND

It is unclear whether acid-base balance disturbances during the perioperative period may impact Clostridium difficile infection (CDI), which is the third most common major infection following cardiac surgery. We hypothesized that perioperative acid-base abnormalities including lactate disturbances may predict the probability of incidence of CDI in patients after cardiac procedures.

METHODS

Of the 12,235 analyzed patients following cardiac surgery, 143 (1.2%) developed CDI. The control group included 200 consecutive patients without diarrhea, who underwent cardiac procedure within the same period of observation. Pre-, intra and post-operative levels of blood gases, as well as lactate and glucose concentrations were determined. Postoperatively, arterial blood was drawn four times: immediately after surgery and successively; 4, 8 and 12 h following the procedure.

RESULTS

Baseline pH was lower and PaO2 was higher in CDI patients (p < 0.001 and p = 0.001, respectively). Additionally, these patients had greater base deficiency at each of the analyzed time points (p < 0.001, p = 0.004, p = 0.012, p = 0.001, p = 0.016 and p = 0.001, respectively). Severe hyperlactatemia was also more common in CDI patients; during the cardiac procedure, 4 h and 12 h after surgery (p = 0.027, p = 0.004 and p = 0.001, respectively). Multivariate logistic regression analysis revealed that independent risk factors for CDI following cardiac surgery were as follows: intraoperative severe hyperlactatemia (OR 2.387, 95% CI 1.155-4.933, p = 0.019), decreased lactate clearance between values immediately and 12 h after procedure (OR 0.996, 95% CI 0.994-0.999, p = 0.013), increased age (OR 1.045, 95% CI 1.020-1.070, p < 0.001), emergent surgery (OR 2.755, 95% CI 1.565-4.848, p < 0.001) and use of antibiotics other than periprocedural prophylaxis (OR 2.778, 95% CI 1.690-4.565, p < 0.001).

CONCLUSION

This study is the first to show that perioperative hyperlactatemia and decreased lactate clearance may be predictors for occurrence of CDI after cardiac surgery.

Von Willebrand factor in aortic or mitral valve stenosis and bleeding after heart valve surgery

OBJECTIVES

Low von Willebrand factor (VWF) increases the risk of bleeding. The objective was to assess the influence of VWF on bleeding after valvular surgery.

METHODS

We studied 82 consecutive patients in median age of 65.5 years with severe isolated aortic stenosis (AS, n = 62) or mitral stenosis (MS, n = 20), undergoing heart valve surgery in extracorporeal circulation. Preoperatively, we assessed VWF antigen (VWF:Ag) and activity (VWF:RCo), a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), and fibrinolysis inhibitors.

RESULTS

Compared with AS, MS patients were more frequently female (80 vs. 55%, p = 0.045) with atrial fibrillation (AF) (80 vs. 8%, p < 0.0001), with no difference in age or comorbidities. Median postoperative drainage was 420 ml for AS, and 425 ml for MS (p = 0.37). Patients with AS had lower VWF:RCo (125.8 [88.5-160.8] vs. 188.0 [140.3-207.3] IU/dl, p = 0.003) and VWF:Ag (135.8 [112.0-171.2] vs. 191.7 [147.3-236.4] IU/dl, p = 0.01) than MS patients. Mean VWF:RCo/Ag ratio was 0.88 ± 0.17, with no intergroup differences. ADAMTS13 levels and activity were similar in both groups. In AS, both VWF:RCo and VWF:Ag correlated inversely with maximal (r = -0.39, p = 0.0003 and r = -0.39, p = 0.0004, respectively) and mean (r = -0.40, p = 0.0004 and r = -0.39, p = 0.0006, respectively) transvalvular pressure gradients. There was no difference in perioperative bleeding between patients following mitral and aortic valve surgery, and bleeding was not associated with VWF:Ag or VWF:RCo.

CONCLUSIONS

In severe AS, VWF levels and activity correlate inversely with transvalvular pressure gradients, and are lower than in severe degenerative MS, but do not affect blood loss after valvular surgery in extracorporeal circulation.

Bioprosthetic or mechanical heart valves: prosthesis choice for borderline patients?-Results from 9,616 cases recorded in Polish national cardiac surgery registry

Background

In middle-aged patients undergoing aortic valve replacement (AVR), the selection of prosthesis type is a complex process. Current guidelines do not unequivocally indicate the type of prosthesis (bioprosthetic or mechanical) recommended for patients between 60–70 years of age. The aim of the study was to present the trends in AVR prosthesis selection in borderline patients over a 10-year period, based on real-life registry data.

Methods

The study population comprised of 9,616 consecutive patients aged between 60–70 years, who underwent isolated AVR between 2006 and 2016 in all cardiac surgery departments in Poland. Data were extracted from the Polish National Registry of Cardiac Surgery.

Results

Among 27,797 consecutive AVR procedures, patients aged 60–70 years represented 34.6% of the population operated on. From 2006 to 2016, bioprosthetic valves (BVs) were implanted in 53.9% cases, (and) mechanical valves (MVs) in 42.1%. The proportion of different valve types changed in time: from 77.5% of MVs vs. 22.5% of BVs in 2006 to 23.2% of MVs vs. 76.8% of BVs in 2016 (P<0.001). The most commonly implanted BV was the Hancock II (used in 36.4% of BV implantations), the most commonly used MV was the Saint Jude Mechanical prosthesis (implanted in 36.4% of MV implantation cases). A multivariable model identified smaller annulus [OR (95% CI) 0.89 (0.86–0.92), P<0.001], atrial fibrillation [OR (95% CI) 1.32 (1.05–1.67), P=0.017], male sex [OR (95% CI) 1.47 (1.24–1.74), P<0.001] and year of implantation [OR (95% CI) 0.75 (0.71–0.79), P<0.001] as predictors of MV implantation.

Conclusions

Patients aged 60–70 years represent more than one-third of all AVR patients. Between 2006 and 2016, the proportion of implanted prostheses has changed dramatically. In 2016 BVs were implanted in nearly 75% of AVR cases, three times more often than in 2006.

Postoperative Serum Lactate Levels for In-Hospital Mortality Prediction Among Heart Transplant Recipients

Background

Hyperlactatemia is a common phenomenon following cardiac surgeries and is associated with prolonged ICU stay and higher morbidity and mortality rates, but such analyses have never focused on patients undergoing heart transplantation (HTX), in whom hyperlactatemia defined with the traditional threshold is observed in nearly every individual. The present study aimed to assess the prognostic value and clinical usefulness of postoperative serum lactate level measurements for in-hospital mortality prediction following HTX.

Material/Methods

Forty-six consecutive patients who underwent HTX in the Department of Cardiovascular Surgery and Transplantology between 2010 and 2015 were enrolled into a retrospective analysis. Serum lactate level measurements within the first 48 h after HTX were obtained from arterial blood gas analyses, that were routinely conducted every 6 h. Lactate clearance was determined for each patient individually throughout 3 different time frames: the first 24-h (Lac clear 0–24) and second 24-h period (Lac clear 24–48), and the first 48 h after surgery (Lac clear 0–48).

Results

The ICU admission serum lactate levels differed between the deceased and survivors (7.6 vs. 4.3 mmol/L; p=0.000). Among all tested postoperative lactate level measurements, only the measurement taken upon ICU admission predicted in-hospital mortality (OR 1.94 95% CI [1.09–3.43]; p=0.024). The receiving operating characteristic (ROC) curve for in-hospital mortality was constructed for ICU admission measurement, with the optimal cut-off point estimated at 7.0 mmol/L.

Conclusions

Serum lactate level measurement upon ICU admission can be used as a predictive parameter for in-hospital mortality among heart transplant recipients. Values greater than 7.0 mmol/L can predict in-hospital mortality with 90% accuracy.

Postoperative hyperlactatemia and serum lactate level trends among heart transplant recipients

Background

Advanced heart failure (HF), that affects 10% of the HF population, is associated with high mortality rate, meeting 50% at 1-year from diagnosis. For these individuals, heart transplantation (HTX) remains the ultimate and the gold-standard treatment option. Serum lactate level measurements has been proven useful for determining the outcome following other cardiac surgeries and among critically ill patients. Increased serum lactate levels are expected following HTX; however, no detailed analysis has been yet performed in this population. The research aims to estimate the prevalence of hyperlactatemia and describe early postoperative serum lactate level trends among heart transplant recipients.

Materials and Methods

Forty-six consecutive patients, who underwent HTX between 2010 and 2015, were enrolled into the retrospective analysis. Serum lactate level measurements within first 48 hours post-HTX were obtained every 6 hours from routinely conducted arterial blood gas analyses. The threshold for hyperlactatemia was considered at >1.6 mmol/L, according to upper limit of normal, based on internal laboratory standardization. The highest observed measurement within the observation, regardless of the time point of observation was determined for each patient individually and was appointed as Peak Value.

Results

Consecutively measured serum lactate levels differed in time (p = 0.000), with the initial increase and subsequent decrease of the values (4.3 vs. 1.9 mmol/l; p = 0.000). The increase from the baseline level to the Peak Value was statistically significant (4.3 vs. 7.0 mmol/l; p = 0.000). Various serum lactate level trends were identified, with one or more hyperlactatemia episodes. Eventually, 50% of the individuals had normal serum lactate levels at the end of the study, and hyperlactatemia was observed in the other half.

Conclusions

Throughout the observation, all of the patients experienced at least one episode of hyperlactatemia, with the median Peak Value of 7.0 (4.5–8.4) mmol/L. Various serum lactate level trends can be identified in post-HTX patients. Further research is required to determine the clinical usefulness of newly reported serum lactate level trends among heart transplant recipients.

Consequences Of Long-Term Bacteria's Exposure To Silver Nanoformulations With Different PhysicoChemical Properties

Purpose

Resistance to antibiotics is a major problem of public health. One of the alternative therapies is silver – more and more popular because of nanotechnology development and new possibilities of usage. As a component of colloid, powder, cream, bandages, etc., nanosilver is often recommended to treat the multidrug-resistant pathogens and we can observe its overuse also outside of the clinic where different physicochemical forms of silver nanoformulations (e.g. size, shape, compounds, surface area) are introduced. In this research, we described the consequences of long-term bacteria exposure to silver nanoformulations with different physicochemical properties, including changes in genome and changes of bacterial sensitivity to silver nanoformulations and/or antibiotics. Moreover, the prevalence of exogenous resistance to silver among multidrug-resistant bacteria was determined.

Materials and Methods

Gram-negative and Gram-positive bacteria strains are described as sensitive and multidrug-resistant strains. The sensitivity of the tested bacterial strains to antibiotics was carried out with disc diffusion methods. The sensitivity of bacteria to silver nanoformulations and development of bacterial resistance to silver nanoformulations has been verified via determination of the minimal inhibitory concentrations. The presence of sil genes was verified via PCR reaction and DNA electrophoresis. The genomic and phenotypic changes have been verified via genome sequencing and bioinformatics analysis.

Results

Bacteria after long-term exposure to silver nanoformulations may change their sensitivity to silver forms and/or antibiotics, depending on the physicochemical properties of silver nanoformulations, resulting from phenotypic or genetic changes in the bacterial cell. Finally, adaptants and mutants may become more sensitive or resistant to some antibiotics than wild types.

Conclusion

Application of silver nanoformulations in the case of multiple resistance or multidrug-resistant bacterial infection can enhance or decrease their resistance to antibiotics. The usage of nanosilver in a clinic and outside of the clinic should be determined and should be under strong control. Moreover, each silver nanomaterial should be considered as a separate agent with a potential different mode of antibacterial action.

Ten-year follow-up after combined coronary artery bypass grafting and transmyocardial laser revascularization in patients with disseminated coronary atherosclerosis

Coronary artery disease involving heavily calcified lesions has been associated with worse short- and long-term outcomes including increased mortality. This paper aims to evaluate long-term survival benefit when CABG + transmyocardial laser revascularization (TMLR) are performed on the hearts of patients with disseminated coronary atherosclerosis (DCA). This novel retrospective study was conducted between 1997 and 2002 and followed 86 patients with ischemic heart disease and severe DCA who underwent TMLR using a Holmium:YAG laser and/or CABG. There were 46 patients who had CABG plus TMLR on at least one heart wall ("combined therapy group") and 40 patients who had CABG or TMLR separately on at least one heart wall ("single therapy group"). For the whole group, actuarial survival at 10 years was 78.3% in the combined group compared to 72.5% in the single therapy group (p = 0.535). Ten-year survival in the combined vs. single therapy group for the anterior heart walls was 100 vs. 72.2% (p = 0.027). For the lateral and posterior heart walls were 73.7 vs. 73.3% (p = 0.97) and 84.2 vs. 72% (p = 0.27), respectively. Kaplan-Meier survival analysis showed benefit only for the anterior heart wall (F Cox test, p = 0.103). Single therapy procedures on all heart walls (odds ratio 1.736, p = 0.264) or on the anterior heart wall only (odds ratio 3.286, p = 0.279) were found to be predictors of 10-year late mortality. Combined therapy (TMLR + CABG) provides benefit for perioperative mortality and long-term survival only when provided on the anterior heart wall. For patients with disseminated coronary atherosclerosis, cardiac mortality was found to be increased when followed up 6 years later, regardless of the therapy applied.

Is right coronary artery chronic total vessel occlusion impacting the surgical revascularization results of patients with multivessel disease? A retrospective study

Introduction

Chronic total occlusion (CTO) is common in the presence of other significantly narrowed coronary arteries. The impact of total occlusion and its association with completeness of revascularization on patients with multivessel disease undergoing coronary artery bypass graft (CABG) remains largely unknown.

Aim

The aim of our study was to compare CABG operation characteristics, as well as 30-day mortality, incidence of post-operative major adverse cardiac and cerebrovascular events (MACCE) between patients with and without CTO in right coronary artery (RCA).

Materials and Methods

A total of 156 consecutive patients were included in the analysis. CTO of RCA or right posterior descending artery (RPD) was diagnosed in 57 patients (CTO-RCA group). Coronary stenosis without CTO in RCA was diagnosed in 99 patients (nonCTO-RCA group). Baseline characteristics were comparable in both groups.

Results

The majority of patients had class II (49.1% vs. 46%, p = 0.86) or class III (42.1% vs. 43%, p = 1.0) Canadian Cardiovascular Society grading system symptoms. Patients in the CTO-RCA group had in average 2.2 grafts implanted, as opposed to 2.4 grafts in patients in the nonCTO-RCA group (p = 0.003). Graft to the RCA was performed in 40.3% patients in the CTO-RCA group and in 81% patients in the nonCTO-RCA group (p = 0.001). The 30-day mortality from any cause or cardiac cause did not differ between groups (7% vs. 2%, p = 0.14 and 3.5% vs. 2%, p = 0.57 respectively). In a multivariate analysis CTO in RCA or RPD and peripheral artery disease were independent predictors of post-operative MACCE (7.9 (1.434-43.045) p = 0.02; 18.8 (3.451-101.833) p < 0.01, respectively).

Conclusions

Chronic total occlusion of RCA was found to be associated with smaller number of grafts performed during the CABG procedure. Although mortality between patients in the CTO-RCA and nonCTO-RCA groups did not differ, patients in the CTO-RCA group had higher incidence of post-operative MACCE.

Similarities and Differences between Silver Ions and Silver in Nanoforms as Antibacterial Agents

Silver is considered as antibacterial agent with well-known mode of action and bacterial resistance against it is well described. The development of nanotechnology provided different methods for the modification of the chemical and physical structure of silver, which may increase its antibacterial potential. The physico-chemical properties of silver nanoparticles and their interaction with living cells differs substantially from those of silver ions. Moreover, the variety of the forms and characteristics of various silver nanoparticles are also responsible for differences in their antibacterial mode of action and probably bacterial mechanism of resistance. The paper discusses in details the aforementioned aspects of silver activity.

Salmonella O48 Serum Resistance is Connected with the Elongation of the Lipopolysaccharide O-Antigen Containing Sialic Acid

Complement is one of the most important parts of the innate immune system. Some bacteria can gain resistance against the bactericidal action of complement by decorating their outer cell surface with lipopolysaccharides (LPSs) containing a very long O-antigen or with specific outer membrane proteins. Additionally, the presence of sialic acid in the LPS molecules can provide a level of protection for bacteria, likening them to human cells, a phenomenon known as molecular mimicry. Salmonella O48, which contains sialic acid in the O-antigen, is the major cause of reptile-associated salmonellosis, a worldwide public health problem. In this study, we tested the effect of prolonged exposure to human serum on strains from Salmonella serogroup O48, specifically on the O-antigen length. After multiple passages in serum, three out of four tested strains became resistant to serum action. The gas-liquid chromatography/tandem mass spectrometry analysis showed that, for most of the strains, the average length of the LPS O-antigen increased. Thus, we have discovered a link between the resistance of bacterial cells to serum and the elongation of the LPS O-antigen.

How to predict the risk of postoperative complications after coronary artery bypass grafting in patients under 50 and over 80 years old. A retrospective cross-sectional study

BACKGROUND

Coronary artery disease (CAD) remains the leading cause of death in developed countries, and there is an increasing number of both young and elderly patients requiring surgical treatment. Despite improvement of conventional risk stratification scores (EuroSCORE II, STS risk score), all of the calculations are estimated based on the typical population and the studies emphasise that the scales may need further investigation and modernisation because demographic changes of the population suffering from CAD are unavoidable.

AIM

To characterise two increasing and challenging cohorts of patients undergoing coronary artery bypass grafting (CABG) and to identify preoperative risk factors for postoperative complications.

METHODS

In the retrospective cross-sectional study, we analysed 388 patients ≥ 80 years old and 190 patients ≤ 50 years old, who underwent CABG consecutively at our Institution. Data were obtained from medical records.

RESULTS

The vast majority of studied patients had commonly described risk factors for cardiovascular diseases, regardless of the age group. Diabetes was present in almost twice as many individuals in the older cohort, when compared to the EuroSCORE population. A similar observation was made for hypertension, which was more frequent in both age groups. Summarising all of the postoperative complications, at least one occurred significantly more frequently among the older group (10% vs. 20.9%, p = 0.001). The vast majority of major adverse cardiac and cerebrovascular events (MACCE) in the older group led to death (79.4%). Among patients ≥ 80 years old, higher New York Heart Association (NYHA) class (p = 0.001, OR 2.05 [1.34-3.12] for every next class) and renal failure (p = 0.02, OR 2.47 [1.16-5.25]) increased the MACCE rate, whereas higher left ven-tricular ejection fraction (LVEF) (p = 0.002, OR 0.81 [0.7-0.93] for every 5%) decreased the risk. Emergent admission was the only factor increasing the occurrence of any postoperative complications among patients ≤ 50 years old (p = 0.007, OR 3.63, 95% CI 1.37-9.62). On the other hand, among patients ≥ 80 years old, emergent admission was not associated with any postoperative complications.

CONCLUSIONS

Young and old patients requiring CABG differ from the standard EuroSCORE population. Postoperative complications are more common among older patients, and MACCE is usually fatal in this age group. Individuals with risk factors for MACCE (higher NYHA class, renal failure, lower LVEF) should be carefully evaluated and qualified, and closely monitored post-surgery.

Long-term follow-up after Holmium:YAG laser revascularization combined with autologous bone marrow derived stem cells implantation

BACKGROUND

Coronary artery disease is a major cause of death worldwide. Despite different standard revascularization options, significant number of patients remains not suitable for any treatment. The aim of the study was to evaluate long-term outcome of patients with diffuse coronary artery disease, treated with autologous stem cells injections combined with transmyocardial laser revascularization.

MATERIAL AND METHODS

9 patients underwent Holmium:YAG laser revascularization and autologous bone marrow derived stem cells implantation between 2007 and 2009 in the Department of Cardiovascular Surgery and Transplantology, John Paul II Hospital, Kraków and were subsequently followed up in 2015.

RESULTS

The mean follow-up period was 73 months. The mean CCS class significantly improved (1.4±0.5 vs 3.3±1.0; p<0.001) and cardiac related hospitalizations significantly decreased (1.1±0.8 vs 3.1±2.1; p<0.001). One death due to heart failure was observed. The mean LVEF increased from 38% to 42% (p>0.05).

CONCLUSIONS

Clinical status improvement was observed with low mortality rate in the long-term follow-up. No new regional wall motion abnormalities were observed, and the increase of global ejection fraction was noted.

Minimally invasive direct coronary artery bypass (MIDCAB) – safety assessment in own material

INTRODUCTION

Minimally invasive direct coronary artery bypass (MIDCAB) allows achieving similar safety and efficacy, with markedly reduced post-operative length of stay when compared to conventional surgical revascularization. Despite promising results, a small number of minimally invasive procedures are performed in Poland. The aim of the study is to assess short- and long-term outcome of MIDCAB revascularization in order to evaluate the safety of the procedure.

MATERIALS AND METHODS

Retrospective observational study analyzing 38 consecutive patients who underwent MIDCAB procedure between 2014 to 2016 in the Department of Cardiovascular Surgery and Transplantology at the John Paul II Hospital, Kraków. Perioperative data was obtained from patient medical records and the median follow-up period valued 17.3 months.

RESULTS

No postoperative deaths and only 1 case of postoperative myocardial infarction were observed. Throughout the follow-up period, the survival rate and freedom from MACCE rate valued 100%, with only 1 case of repeated revascularization.

CONCLUSIONS

Minimally invasive revascularization is a safe procedure which can be performed with excellent short- and long-term outcome in low-risk patients.

Risk factors for in-hospital mortality after coronary artery bypass grafting in patients 80 years old or older: a retrospective case-series study

BACKGROUND

Age remains a significant and unmodifiable risk factor for cardiovascular diseases, and an increasing number of patients older than 80 years of age undergo Coronary Artery Bypass Grafting (CABG). Old age is also an independent risk factor for postoperative complications. The aim of this study is to describe the population of patients 80 years of age or older who underwent CABG procedure and to assess the mortality rate and risk factors for in-hospital mortality.

METHODS

A retrospective case-series study analyzing 388 consecutive patients aged 80 years of age or older who underwent isolated CABG procedure between 2010 and 2014 in the Department of Cardiovascular Surgery and Transplantology, John Paul II Hospital, Krakow.

RESULTS

In-hospital mortality stood at 7%, compared to 3.4% for all isolated CABG procedures at our Institution. In an univariate logistic regression analysis, risk factors for in-hospital mortality were as follows: NYHA class (p = 0.005, OR 1.95, 95% CI [1.23-3.1]), prolonged mechanical ventilation (p < 0.001, OR 7.08, 95% CI [2.47-20.3]), rethoracotomy (p = 0.04, OR 3.31, 95% CI [1.04-10.6]), duration of the procedure and ECC (for every 10 min p = 0.01, OR 1.01, 95% CI [1.0-1.01]; p = 0.03, OR 1.01, 95% CI [1.0-1.02], respectively), PRBC, FFP, and PLT transfusion (for every unit transfused p = 0.004, OR 1.42, 95% CI [1.12-1.8]; p = 0.002, OR 1.55, 95% CI [1.18-2.04]; p = 0.009, OR 1.93, 95% CI [1.18-3.14], respectively). Higher LVEF (p = 0.02, OR 0.97, 95% CI [0.94-0.99]) and LIMA graft implantation (p = 0.04, OR 0.36, 95% CI [0.13-0.98) decreased the in-hospital mortality. Death before discharge was more often observed in patients with multiple risk factors for cardiovascular diseases (0-2 -5.7%; 3-7.4%, 4-26.6%; p = 0.03).

CONCLUSIONS

Older age is associated with higher in-hospital mortality after isolated CABG at our Institution. Risk stratification scores and individualized risk evaluation, centered on comorbidities, NYHA class and left ventricular function, should be assessed in all cases. Whenever suitable, LIMA grafts should be used. Prolonged procedure and ECC time worsen the short-term outcome. Elderly individuals should be closely monitored postoperatively and the care should be focused on excessive blood loss and respiratory failure.

Impact of Postoperative Bleeding on Short-Term Outcome in Patients After Orthotopic Heart Transplantation: A Retrospective Cohort Study

BACKGROUND Orthotopic heart transplantation (HTX) remains the ultimate treatment option in patients with end-stage heart failure, endorsed by the European Society of Cardiology guidelines. The aim of the study is a complex evaluation of the postoperative bleeding after HTX and its influence on short-term outcome. MATERIAL AND METHODS A retrospective cohort study consisted of 53 patients (4 females and 49 males, median age 52.5 years, IQR 17 years) who underwent HTX in the Department of Cardiovascular Surgery and Transplantology of John Paul II Hospital in Krakow between 2007 and 2014. RESULTS The median chest tube output within first 24 hours after the surgery was 695 (550-870) mL. Bleeding decreased throughout the observation (p=0.000). The first postoperative hemoglobin level was a significant predictor of excessive blood loss (p=0.017). The volume of chest tube output increased the duration of mechanical ventilation (p=0.046) and the incidence of re-exploration after first 24 hours of observation (p=0.049). In patients with higher chest tube output, more packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelet (PLT) transfusions were required (p=0.000, p=0.019, and p=0.000, respectively). Early rethoracotomy (within the first 24 hours post-surgery) increased the in-hospital mortality (p=0.021; OR 7.43 [1.36-40.64]). CONCLUSIONS The study demonstrates the importance of postoperative bleeding and bleeding complications for short-term outcome in our post-HTX cohort. Throughout the analysis, the first postoperative hemoglobin level was detected to be a significant predictor of postoperative blood loss.

Coronary Artery Disease in Young Adults: Who Needs Surgical Revascularization? A Retrospective Cohort Study

BACKGROUND

Coronary artery disease (CAD) is a major cause of death and disability in developed countries. Despite the fact that prevalence accrues with age, an increasing number of young patients suffering from CAD is being observed worldwide. The aim of this study is to describe the population of young adults suffering from CAD and requiring coronary artery bypass grafting (CABG), and to assess early outcomes after the procedure.

METHODS

A retrospective cohort study analyzed 190 consecutive patients aged ≤50 years old that underwent CABG between 2010 and 2014. Baseline characteristics and operative data were presented in the study. Postoperative complications, such as major adverse cardiac and cardiovascular events (MACCE), prolonged mechanical ventilation (&gt;72 hours), bleeding requiring reexploration, sternal dehiscence, and others were assessed.

RESULTS

A population comprising mostly overweight or obese males with a mean age of 46 ± 4.1 years was analyzed. Patients suffered mostly from three-vessel disease (81%), hypertension (74.7%), and had previous history of myocardial infarction (MI) (60%). The majority of patients had normal left ventricle ejection fraction (LVEF) (83.1%). 22.6% of cases were emergent procedures. Perioperative mortality was low (1%) and overall MACCE rate stood at 2.6%. Emergent surgery was associated with a higher incidence of postoperative complications (P = .007). The number of diseased vessels, LVEF, and CCS/NYHA class-on-admission was not associated with a higher incidence of postoperative complications (P &gt; .05 for all).

CONCLUSION

CAD in young patients remains an issue described insufficiently in the literature. Among our study cohort of younger patients undergoing CABG, the majority of the patients had multivessel disease and were slightly symptomatic with normal LVEF. Although the postoperative complication rate was low, the percentage of emergent surgeries was alarmingly high in this population. Consistent with the literature, we highlight the importance of CAD screening in the young population to detect subclinical disease, which might be treated therapeutically or operated electively.

The participation of outer membrane proteins in the bacterial sensitivity to nanosilver

The presented study is to analyze the participation of outer membrane proteins of Gram- negative bacteria in sensitivity to silver nanomaterials. The mechanism of interaction of silver with the bacterial cell is best described in this group of microorganisms. There are several theories regarding the effectiveness of antimicrobial ions and nanosilver, and at the indicated differences in the way they work. Outer membrane proteins of Gram-negative bacteria are involved in the procurement of silver from the environment and contribute to the development mechanisms of resistance to nanometals. They are measurable parameter in the field of cell phenotypic response to the presence of Gram-negative bacteria in the environment silver nanoforms: its properties, chemical composition, content or times of action. Proteomic methods (including two dimensional electrophoresis and MALDI‑TOF MS) are therefore relevant techniques for determining the susceptibility of bacteria to silver and the changes taking place in the outer membrane under the influence: uptime/exposure and physical and chemical parameters of silver nanomaterials. Many products containing nanosilver is still in the research phase in terms of physico‑chemical characteristics and biological activity, others have been already implemented in many industries. During the very fast nanotechnology developing and introduction to the market products based on the nanosilver the bacterial answer to nanosilver is needed.

Selection and electrophoretic characterization of Salmonella enterica subsp. enterica biocide variants resistant to antibiotics

The proposed research outlines a serious common concern of Salmonella resistance to antimicrobials following prolonged exposure to the disinfectants (biocides). These phenotypes of bacteria could potentially result in hard to treat infections. Typical for avian sources, biocide sensitive S. enterica subsp. enterica serovars: Typhimurium, Enteritidis, Virchow and Zanzibar and their isogenic biocide-tolerant variants were studied in order to investigate bacteriostatic effect of two commercially available biocide formulations: potassium peroxymonosulfate (P) and dodecylamine based structure (triamine, D). We found that cultivating of the bacteria in the medium supplemented with a blend containing P did not influence their antibiotic susceptibility pattern. In contrast, tolerance of bacteria to D compound resulted in resistance to co-trimoxazole, cefotaxime and ciprofloxacin of which two cefotaxime and ciprofloxacin are used commonly for the treatment of invasive Salmonella infections in humans. The dependency between OMP patterns and the level of Salmonella survival in media containing the biocides was observed merely in serovar Typhimurium. In conclusion, these results suggest that Salmonella strains challenged by prolonged treatment with the disinfectants become resistant to antibiotics, however it depends on Salmonella serovar and the chemical used. This paper also highlights the loop-mediated isothermal amplification (LAMP) as a technique that offers great benefits to microbiological detecting of Salmonella species in the samples.

Total arterial myocardial revascularization in patients over 70 years old - a new trend in coronary surgery in elderly

INTRODUCTION

In modern society, civilization has extended the life expectancy of developed nations. The demographic analysis of Eurostat (European Statistical Office) predicts the increase of the population over 70 years old in Western Europe from 15.2% reported in 1995 to 19.5% in 2020. Undoubtedly, the incidence of cardiovascular diseases increases with age. Nowadays, they are the most commonly diagnosed disease, as well as the most common cause of death in patients over 70 years old. Therefore, a significant increase of surgeries in elderly patients, reaching up to 30%, is reported in cardiac surgery. As changes in operating technique are being observed, better outcomes of surgeries in elderly patients are being noted. With over 10 years of observation, more beneficial results are noted for arterial revascularization with usage of arterial grafts compared with venous ones. The aim of the study is to evaluate the safety of harvesting both internal mammary arteries and radial artery in CABG in patients over 70 years old and to analyze the incidence of major adverse cardiac and cerebrovascular events (MACCE) and other postoperative complications in this cohort.

MATERIALS AND METHODS

In a retrospective observational study we analyzed 101 cases, where TAMR was applied in patients aged 70 yo or older between 2003 to 2009 in the Department of Cardiovascular Surgery and Transplantology, John Paul II Hospital, Kraków. Exclusion criteria included among others low left ventricular ejection fraction, high Euroscore, and accompanying valvular disease. Data was obtained from patient medical records. Baseline characteristics, intraoperative data and postoperative complications were assessed. All surgeries were performed in extracorporeal circulation and via median sternotomy.

RESULTS

In the study cohort, most patients suffered from multi-vessel disease (65.3%), and all required at least 2 bypass grafts. Left internal mammary artery (LIMA) was used in all cases, right internal mammary artery (RIMA) in 30.7%, and radial artery (RA) in 95% of surgeries. In 6.9% of individuals additional transmyocardial laser revascularization was applied due to disseminated coronary artery disease. The in-hospital mortality stood at 1.98%, however there were no cardiac deaths reported. The postoperative MACCE incidence was 6.94% due to 6 cases of myocardial infarction, and 1 case of acute stroke. The in-hospital mortality was 1.98%. Other postoperative complications occurred as follows: rethoracotomy (2.9%), blood products transfusions (69.3%), prolonged mechanical ventilation (9.9%), atrial fibrillation (15.8%), deep wound infection (3.96%), sternal dehiscence (1.98%).

CONCLUSIONS

Technique of TAMR in coronary artery bypass grafting is a safe method in low-risk patients over 70 years old and can be performed with good short-term outcome. Further evaluation analyzing the long-term benefits in elderly patients of TAMR is warranted.