Efficacy of Vaporized Hydrogen Peroxide Combined with Silver Ions against Multidrug-Resistant Gram-Negative and Gram-Positive Clinical Isolates.

Antimicrobial resistance (AMR) is a serious public health problem that results in high morbidity and mortality rates. In particular, multidrug-resistant (MDR) strains circulating in hospital settings pose a major threat as they are associated with serious nosocomial infections. Therefore, regular cleaning and disinfection procedures, usually using chemical disinfectants, must be implemented in these facilities. Hydrogen peroxide (HP)-based disinfectants have proven high microbicidal activity and several comparative advantages over conventional disinfectants. We assessed the in vitro biocidal activity of an 8% HP solution combined with 30 mg/L silver ions (HP + Ag) against MDR clinical isolates of Klebsiella pneumoniae (MDRKp) and Pseudomonas aeruginosa (MDRPa), and methicillin-resistant Staphylococcus aureus (MRSA). Accordingly, the in vitro antibacterial activity was determined using the macrodilution method, and the efficacy was determined for 30 min in terms of (1) activity on bacteria in suspension and (2) activity on surfaces using vaporized HP + Ag on a 20 cm2 stainless steel surface. A strong bactericidal effect of HP + Ag was observed against MDRKp, MDRPa, and MRSA strains, with minimum inhibitory concentrations and minimum bactericidal concentrations between 362.5 and 5800 mg/L. A strong effect was observed during the 30 min of HP + Ag exposure to the resistant clinical isolates, with over 4-Log10 reduction in CFUs. Regarding the efficacy of the disinfectant on surfaces, bacterial load reductions of >99% were observed. These results suggest that HP + Ag is potentially useful as an effective disinfectant for decontaminating surfaces in hospital settings suspected of contamination with MDR bacteria.

Integrating In Vitro and In Silico Analysis of a Cationic Antimicrobial Peptide Interaction with Model Membranes of Colistin-Resistant Pseudomonas aeruginosa Strains.

Bacterial antibiotic resistance is a serious global public health concern. Infections caused by colistin-resistant Pseudomonas aeruginosa (CRPa) strains represent a serious threat due to their considerable morbidity and mortality rates, since most of the current empirical antibiotic therapies are ineffective against these strains. Accordingly, cationic antimicrobial peptides (CAMPs) have emerged as promising alternatives to control resistant bacteria. In this study, the interaction of a CAMP derived from cecropin D-like (∆M2) with model membranes mimicking bacterial biomembranes of wild-type (WTPa) strains of P. aeruginosa and CRPa was evaluated through in vitro and in silico approaches. In vitro interaction was determined by infrared spectroscopy, whereas in silico molecular dynamics was performed to predict specific interactions between amino acids of ∆M2 and lipids of model membrane systems. Experimental analysis showed this peptide interacted with the lipids of bacterial-like model membranes of WTPa and CRPa. In both cases, an increase in the concentration of peptides induced an increase in the phase transition temperature of the lipid systems. On the other hand, the peptides in solution underwent a transition from a random to a helical secondary structure after interacting with the membranes mostly favored in the CRPa system. The α-helix structure percentage for ΔM2 interacting with WTPa and CRPa lipid systems was 6.4 and 33.2%, respectively. Finally, molecular dynamics showed ∆M2 to have the most affinities toward the phospholipids palmitoyl-oleyl-phosphatidylglycerol (POPG) and palmitoyl-oleoyl-phosphatidylethanolamine (POPE) that mimic membranes of WTPa and CRPa, respectively. This work provides clues for elucidating the membrane-associated mechanism of action of ∆M2 against colistin-susceptible and -resistant strains of Pseudomonas aeruginosa.

Antibacterial Activity of a Cationic Antimicrobial Peptide against Multidrug-Resistant Gram-Negative Clinical Isolates and Their Potential Molecular Targets.

Antimicrobial resistance reduces the efficacy of antibiotics. Infections caused by multidrug-resistant (MDR), Gram-negative bacterial strains, such as Klebsiella pneumoniae (MDRKp) and Pseudomonas aeruginosa (MDRPa), are a serious threat to global health. However, cationic antimicrobial peptides (CAMPs) are promising as an alternative therapeutic strategy against MDR strains. In this study, the inhibitory activity of a cationic peptide, derived from cecropin D-like (ΔM2), against MDRKp and MDRPa clinical isolates, and its interaction with membrane models and bacterial genomic DNA were evaluated. In vitro antibacterial activity was determined using the broth microdilution test, whereas interactions with lipids and DNA were studied by differential scanning calorimetry and electronic absorption, respectively. A strong bactericidal effect of ΔM2 against MDR strains, with minimal inhibitory concentration (MIC) and minimal bactericidal concentrations (MBC) between 4 and 16 µg/mL, was observed. The peptide had a pronounced effect on the thermotropic behavior of the 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/1,2-dimyristoyl-sn-glycero-3-phosphorylglycerol (DMPG) membrane models that mimic bacterial membranes. Finally, the interaction between the peptide and genomic DNA (gDNA) showed a hyperchromic effect, which indicates that ΔM2 can denature bacterial DNA strands via the grooves.

A novel filtration system based on ceramic silver-impregnated pot filter combined with adsorption processes to remove waterborne bacteria.

Halving the proportion of the people without sustainable access to safe drinking water and basic sanitation is among the Sustainable Development Goals (SDG). Lack of access to safe drinking water has been associated with the prevalence of waterborne diseases. Due to this reported association, the development of household water treatment devices has been an alternative to improve the quality supply of domestic water. In this study, we aimed to evaluate the performance of a ceramic silver-impregnated pot filter (CSF) system coupled with an adsorption process, composed of silver-impregnated granular activated carbon and zeolite (CSF + GAC-Z), to remove waterborne bacteria Escherichia coli and Salmonella spp. from spiked water. The performance of this system was compared with the conventional CSF system. In this respect, we evaluated six CSF and six CSF + GAC-Z using spiked water with 103 and 102 CFU/mL of E. coli and Salmonella spp. The mean percentage of removals ranged between 98% and 99.98%. The highest bacterial removal efficiency was recorded by the CSF + GAC-Z (99%) and CSF (99.98%) for E. coli and Salmonella spp., respectively, but no significant statistical differences were found between filtration systems. Our findings suggest that the CSF + GAC-Z system was effective in the removal of waterborne bacteria from spiked water.

A Novel Cecropin D-Derived Short Cationic Antimicrobial Peptide Exhibits Antibacterial Activity Against Wild-Type and Multidrug-Resistant Strains of Klebsiella pneumoniae and Pseudomonas aeruginosa.

Infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa and Klebsiella pneumoniae are a serious worldwide public health concern due to the ineffectiveness of empirical antibiotic therapy. Therefore, research and the development of new antibiotic alternatives are urgently needed to control these bacteria. The use of cationic antimicrobial peptides (CAMPs) is a promising candidate alternative therapeutic strategy to antibiotics because they exhibit antibacterial activity against both antibiotic susceptible and MDR strains. In this study, we aimed to investigate the in vitro antibacterial effect of a short synthetic CAMP derived from the ΔM2 analog of Cec D-like (CAMP-CecD) against clinical isolates of K pneumoniae (n = 30) and P aeruginosa (n = 30), as well as its hemolytic activity. Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of CAMP-CecD against wild-type and MDR strains were determined by the broth microdilution test. In addition, an in silico molecular dynamic simulation was performed to predict the interaction between CAMP-CecD and membrane models of K pneumoniae and P aeruginosa. The results revealed a bactericidal effect of CAMP-CecD against both wild-type and resistant strains, but MDR P aeruginosa showed higher susceptibility to this peptide with MIC values between 32 and >256 µg/mL. CAMP-CecD showed higher stability in the P aeruginosa membrane model compared with the K pneumoniae model due to the greater number of noncovalent interactions with phospholipid 1-Palmitoyl-2-oleyl-sn-glycero-3-(phospho-rac-(1-glycerol)) (POPG). This may be related to the boosted effectiveness of the peptide against P aeruginosa clinical isolates. Given the antibacterial activity of CAMP-CecD against wild-type and MDR clinical isolates of P aeruginosa and K pneumoniae and its nonhemolytic effects on human erythrocytes, CAMP-CecD may be a promising alternative to conventional antibiotics.

Antimicrobial Contribution of Chitosan Surface-Modified Nanoliposomes Combined with Colistin against Sensitive and Colistin-Resistant Clinical Pseudomonas aeruginosa.

Colistin is a re-emergent antibiotic peptide used as a last resort in clinical practice to overcome multi-drug resistant (MDR) Gram-negative bacterial infections. Unfortunately, the dissemination of colistin-resistant strains has increased in recent years and is considered a public health problem worldwide. Strategies to reduce resistance to antibiotics such as nanotechnology have been applied successfully. In this work, colistin was characterized physicochemically by surface tension measurements. Subsequently, nanoliposomes coated with highly deacetylated chitosan were prepared with and without colistin. The nanoliposomes were characterized using dynamic light scattering and zeta potential measurements. Both physicochemical parameters fluctuated relatively to the addition of colistin and/or polymer. The antimicrobial activity of formulations increased by four-fold against clinical isolates of susceptible Pseudomona aeruginosa but did not have antimicrobial activity against multidrug-resistant (MDR) bacteria. Interestingly, the free coated nanoliposomes exhibited the same antibacterial activity in both sensitive and MDR strains. Finally, the interaction of colistin with phospholipids was characterized using molecular dynamics (MD) simulations and determined that colistin is weakly associated with micelles constituted by zwitterionic phospholipids.

Removal of E. coli and Salmonella in pot ceramic filters operating at different filtration rates.

The use of pot ceramic filters PCF to improve the domestic water quality supply has been recognized as an alternative in regions where there is unsecure water treatment or contamination of the treated water during transport and storage and an absence of safe drinking water. The aim of this study was to evaluate a model of PCF impregnated with colloidal silver under three filtration rates (1.0, 2.0 and 3.0 L/h) and three E. coli and Salmonella spp concentrations (104, 103 and 102 CFU/mL). The evaluation was made using spiked water having a turbidity of 29.9 ±â€¯4.4 NTU and conductivity of 176 ±â€¯31.7 µS/cm. The results showed a turbidity removal efficiency of 97% and average effluent of 0.9 NTU. The microbiological efficiency removal was of 2 Log Reduction Value (LRV) for E. coli and 1 LRV for Salmonella spp. There were not found significant statistical differences between the filtration rates and the removal efficiencies for turbidity E. coli and Salmonella spp. It was observed that the microbiological removal efficiency was affected by biofilm formation a phenomenon that was attributed to the presence of Salmonella spp. The combination of chemical and mechanical cleaning methods contributed to the elimination of the biofilm.

Adult T-cell leukemia/lymphoma can be indistinguishable from other more common T-cell lymphomas. The University of Miami experience with a large cohort of cases.

Adult T-cell leukemia/lymphoma, an aggressive T-cell neoplasm, is causally linked to human T-cell lymphotropic virus type 1 and based on this association has a distinct geographic distribution. In our United States-based practice, whose population is enriched for immigrants from human T-cell lymphotropic virus type 1 endemic areas, we have identified that a subset of adult T-cell leukemia/lymphoma, in the absence of human T-cell lymphotropic virus type 1 identification, are indistinguishable from other more common T-cell neoplasms. We retrospectively gathered serology results for anti-human T-cell lymphotropic virus type 1/2 antibody in patients diagnosed with T-cell neoplasms at our institution. A total of 220 human T-cell lymphotropic virus type 1/2 positive patients with T-cell neoplasms were identified; 199 (91%) were correctly classified as adult T-cell leukemia/lymphoma or provisionally as peripheral T-cell lymphoma (serology testing pending). Twenty-one cases (9%) were initially misclassified, including the following: 13 presenting with skin +/- peripheral blood involvement and misclassified as mycosis fungoides/Sezary syndrome; 7 with lymphomatous disease, absence of leukemic involvement, and diffuse CD30 expression, misclassified as ALK- negative anaplastic large-cell lymphoma; 1 thought to represent T-prolymphocytic leukemia with TCL-1 gene rearrangement and diffuse marrow involvement. We also present an example of adult T-cell leukemia/lymphoma, which mimicked lymphoepithelioid variant of peripheral T-cell lymphoma also with diffuse marrow involvement. A subset of adult T-cell leukemia/lymphoma can closely mimic a variety of other more common T-cell neoplasms. Due to its extreme clinicopathologic heterogeneity, identification of adult T-cell leukemia/lymphoma requires a high level of suspicion based on patient demographic alone, which should prompt anti-human T-cell lymphotropic virus type 1/2 serology testing in all T-cell neoplasms developing in patients of appropriate demographic. Absence of high level of suspicion, adult T-cell leukemia/lymphoma is easily misclassified.

Bone Marrow-Liver-Spleen Type of Large B-Cell Lymphoma Associated with Hemophagocytic Syndrome: A Rare Aggressive Extranodal Lymphoma.

Recently, an unusual subtype of large B-cell lymphoma (LBCL) with distinctive clinicopathologic features has been recognized; it is characterized by involvement of bone marrow with or without liver and/or spleen, but no lymph node or other extranodal sites, usually associated with fever, anemia, and hemophagocytic lymphohistiocytosis (HLH). Because of this distinctive clinical presentation, it has been designated "bone marrow-liver-spleen" (BLS) type of LBCL. To date there is only one series of 11 cases of BLS type of LBCL with detailed clinical, pathologic, and cytogenetic data. Herein, we describe a case of BLS type LBCL presenting with associated HLH in a 73-year-old female. The bone marrow core biopsy showed cytologically atypical large lymphoma cells present in a scattered interstitial distribution and hemophagocytosis and infrequent large lymphoma cells were seen in the bone marrow aspirate smears. Circulating lymphoma cells were not seen in the peripheral blood smears. The patient underwent treatment with chemotherapy (R-CHOP) but unfortunately passed away 2 months after initial presentation. BLS type of LBCL is a very rare and clinically aggressive lymphoma whose identification may be delayed by clinicians and hematopathologists due to its unusual clinical presentation and pathologic features.

Correlación entre la resonancia magnética y la ecocardiografía transtorácica en la evaluación de la insuficiencia pulmonar en pacientes pediátricos con cardiopatía congénita / Correlation between magnetic resonance and transthoracic echocardiogram for the assessment of pulmonary insufficiency in pediatric patients with congenital heart disease

Objetivo: Establecer la correlación y la concordancia del grado de severidad de insuficiencia pulmonar entre la ecocardiografía y la resonancia magnética en la población pediátrica de un hospital de tercer nivel de atención. Métodos: Se estudiaron 20 pacientes con diagnóstico de cardiopatía congénita con insuficiencia pulmonar, a quienes se les realizaron ecocardiograma transtorácico y resonancia magnética. Se calculó: relación de la vena contracta y el chorro de insuficiencia pulmonar, tiempo de hemipresión, presencia de flujo diastólico reverso en tronco pulmonar e índice de insuficiencia pulmonar; en cuanto a la resonancia magnética: la fracción y el volumen regurgitante. Se realizó análisis de correlación mediante coeficiente de correlación de Spearman y prueba de Tau B. Resultados:La tetralogía de Fallot corregida representó el 60% de la muestra. La correlación fue significativa en la fracción y el volumen regurgitante de la resonancia magnética, así como en las variables ecocardiográficas índice de insuficiencia pulmonar en modo M, vena contracta y porcentaje de vena contracta/arteria pulmonar. La correlación entre los grados de insuficiencia pulmonar por resonancia magnética y ecocardiografía fue 0,85 (p < 0,001). Conclusiones: La vena contracta y el porcentaje VC/AP son variables que tienen alta correlación con la fracción y el volumen regurgitante de la resonancia magnética nuclear para evaluar la insuficiencia pulmonar en pacientes en posoperatorio de cardiopatía congénita.

Motivation: To establish the correlation and concordance of the degree of severity of pulmonary insufficiency between echocardiography and magnetic resonance in pediatric population of a third level hospital. Methods: 20 patients diagnosed with congenital heart disease and with pulmonary insufficiency were studied, they underwent a transthoracic echocardiogram and a magnetic resonance. The relationship of the vena contracta, the pulmonary regurgitation jet, the pressure half-time time, the presence of reversed end-diastolic flow and the pulmonary insufficiency index were calculated. With regards to the magnetic resonance, both fraction and regurgitant volume were measured. An analysis of the correlation was conducted.by means of the Spearman correlation and the Tau B. Results: Corrected Fallot's tetralogy represented 60% of the sample. The correlation was significant in the fraction and the regurgitant volume of the magnetic resonance, as well as in the echocardiographic variables of M-mode pulmonary insufficiency, vena contracta and vena contracta/pulmonary artery percentage. The correlation between the degrees of pulmonary insufficiency by magnetic resonance and echocardiogram was 0.85 (p < 0.001). Conclusions: Vena contracta and the VC/PA percentage are variables that present high correlation with the fraction and the regurgitant volume of nuclear magnetic resonance to assess pulmonary insufficiency in patients after a congenital cardiac disease surgery.