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Background: Cooling towers (CTs) are crucial to myriad industrial processes, supporting thermal exchange between fluids in heat exchangers using water from lakes and rivers as coolant. However, CT water can sometimes introduce microbial contaminants that adhere to and colonize various surfaces within the CT system. These microorganisms can form biofilms, significantly hindering the system's thermal exchange efficiency. Current treatment strategies employ oxidizing biocides to prevent microbial growth. However, despite their affordability, they do not eliminate biofilms effectively and can lead to corrosive damage within the system. Herein, we aim to devise an anti-biofilm strategy utilizing hydrolytic enzymes (such as α-amylase, glucoamylase, pectin-lyase, cellulase, protease, and DNase) alongside antibiotics (including meropenem, ciprofloxacin, gentamicin, erythromycin, chloramphenicol, and ceftriaxone) to combat microbial growth and biofilm formation in cooling systems., Results: All enzymes reduced the development of the biofilms significantly compared to controls (p < 0.05). The polysaccharidases exhibited biomass reduction of 90%, except for pectin-lyase (80%), followed by DNAse and protease at 43% and 49%, respectively. The antibiotics reduced the biofilms of 70% of isolates in concentration of > 2 mg/mL. The minimal biofilm eradication concentration (MBEC) lower than 1 mg/mL was detected for some 7-day-old sessile isolates. The enzymes and antibiotics were also used in combination against biofilms using the modified Chequerboard method. We found six synergistic combinations, with Fractional inhibitory concentrations (FIC) < 0.5, out of the ten tested. In the presence of the enzymatic mixture, MBECs presented a significant decrease (p < 0.05), at least 4-fold for antibiotics and 32-fold for enzymes. Moreover, we characterized high molecular weight (> 12 kDa) exopolysaccharides (EPS) from biofilms of ten isolates, and glycosyl composition analysis indicated a high frequency of glucose, mannose, erythrose, arabinose, and idose across isolates EPS contrasting with rhamnose, allose, and those carbohydrates, which were detected in only one isolate., Conclusion: The synergistic approach of combining enzymes with antibiotics emerges as a highly effective and innovative strategy for anti-biofilm intervention, highlighting its potential to enhance biofilm management practices., (© 2024. The Author(s).)

Euterpe oleracea (Açaí) fruit are widely consumed at the Brazilian Amazon region, and biological potentials such as immunomodulatory and antioxidant have been described for its extracts. However, its antimicrobial properties remain poorly investigated. Here, the antimicrobial and antibiofilm activities of the methanolic extract of an artisanally-manufactured açaí pulp (MEAP) were evaluated against clinical isolates of Staphylococcus aureus. Besides, MEAP interference on the activity of antimicrobial drugs of clinical relevance was explored, and its cytotoxicity against hepatocellular carcinoma cells (HepG2) was investigated. Biochemical and physicochemical properties of the pulp were investigated, and the presence of polyphenols on the extract was confirmed. For the first time, we report that the methanolic extract of açaí pulp is effective against planktonic cells and biofilms of S. aureus, and also decreased the proliferation of HepG2 cells. Statistically significant synergism was observed when the extract was combined to the tested antimicrobials except for erythromycin, and all biochemical and physicochemical parameters ranged within the accepted values established by the Brazilian legislation. Our data open doors for more studies on the antimicrobial activity of phytomolecules isolated from Euterpe oleracea extracts, and also for its combined use with antimicrobial drugs., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

This study aimed to investigate for the first time the in vitro antibiofilm effectiveness of two chloramphenicol liposome formulations against biofilms of potentially pathogenic bacteria associated to corrosion isolated from the water of cooling towers from a Brazilian industry. Antibiofilm assays with liposomes were performed in 96-wells microtiter plates, and data was compared to free chloramphenicol treatment. Chloramphenicol-loaded liposomes were successfully produced using the dehydration-rehydration method, with vesicle diameters of 131 nm (100 nm membrane extrusion) and 182 nm (200 nm membrane extrusion) assessed by dynamic light scattering. The liposomes obtained by 100 nm membrane extrusion were more effective than 200 nm membrane extrusion vesicles against the biofilms after overnight exposure, and the free drug had no antibiofilm effect. Our study open doors for more investigations on liposome entrapment of antimicrobial compounds such as biocides of industrial use, for controlling biofilm formation in aquatic environments.

The epidemiology of Staphylococcus aureus infections has evolved in recent years, as this species is a major Gram-positive pathogen associated with healthcare services. The antimicrobial resistance of this species raises an urgent need for new treatment strategies. Fruits play important nutritional and economic roles in society, but their biological and pharmacological features are poorly explored when compared to nonedible parts of plants such as barks and leaves. In this study, we show that the cashew apple juice [cashew juice pulp (CJP)] extract is active against the planktonic cells of S. aureus strains, and for the first time, we show that CJP is also active against S. aureus biofilms. High performance liquid chromatography and gas chromatography-mass spectrometry analyses were conducted to prospect for polyphenols and free carbohydrates, respectively. Cashew apple juice, which is rich in nutrients, is widely consumed in Brazil; therefore, the quality attributes of CJPs were investigated. Samples were evaluated for pH, total titratable acidity, vitamin C levels, and total soluble solids. We also detected an antagonistic interference of CJP when it was combined with different antimicrobial drugs., (Copyright © 2016. Published by Elsevier B.V.)

A bacteriocinogenic Lactobacillus rhamnosus L156.4 strain isolated from the feces of NIH mice was identified by 16S rRNA gene sequencing and MALDI-TOF mass spectrometry. The entire genome was sequenced using Illumina, annotated in the PGAAP, and RAST servers, and deposited. Conserved genes associated with bacteriocin synthesis were predicted using BAGEL3, leading to the identification of an open reading frame (ORF) that shows homology with the L. rhamnosus GG (ATCC 53103) prebacteriocin gene. The encoded protein contains a conserved protein motif associated a structural gene of the Enterocin A superfamily. We found ORFs related to the prebacteriocin, immunity protein, ABC transporter proteins, and regulatory genes with 100% identity to those of L. rhamnosus HN001. In this study, we provide evidence of a putative bacteriocin produced by L. rhamnosus L156.4 that was further confirmed by in vitro assays. The antibacterial activity of the substances produced by this strain was evaluated using the deferred agar-spot and spot-on-the lawn assays, and a wide antimicrobial activity spectrum against human and foodborne pathogens was observed. The physicochemical characterization of the putative bacteriocin indicated that it was sensitive to proteolytic enzymes, heat stable and maintained its antibacterial activity in a pH ranging from 3 to 9. The activity against Lactobacillus fermentum , which was used as an indicator strain, was detected during bacterial logarithmic growth phase, and a positive correlation was confirmed between bacterial growth and production of the putative bacteriocin. After a partial purification from cell-free supernatant by salt precipitation, the putative bacteriocin migrated as a diffuse band of approximately 1.0-3.0 kDa by SDS-PAGE. Additional studies are being conducted to explore its use in the food industry for controlling bacterial growth and for probiotic applications.

This study aimed to investigate the in vitro antifungal effectiveness of five different formulations against dandruff and ringworm dermatophytes. Candida albicans was also included in our assays. Fungal susceptibility tests were performed with planktonic cells and biofilms of reference strains. Microbiological and physicochemical quality parameters were assessed for all formulations. Our data indicated that the formulations were effective against the dermatophytes strains, and to our knowledge, the effectiveness of cosmetic formulations against fungal biofilms is shown for the first time. The formulations were considered effective against the explored dermatophytes and were considered safe given the adequate microbiological and physicochemical characteristics shown in the proposed assays.

Staphylococcus aureus and Pseudomonas aeruginosa are part of the human microbiota and are also important bacterial pathogens, for which therapeutic options are lacking nowadays. The combined administration of corticosteroids and antimicrobials is commonly used in the treatment of infectious diseases to control inflammatory processes and to minimize potential toxicity of antimicrobials, avoiding sequelae. Although different pharmaceutical dosage forms of antimicrobials combined to corticosteroids are available, studies on the interference of corticosteroids on the pharmacological activity of antimicrobials are scarce and controversial. Here, we provide evidence of the interference of dexamethasone on the pharmacological activity of clinically important antimicrobial drugs against biofilms and planktonic cells of S. aureus and P. aeruginosa . Broth microdilution assays of minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) of gentamicin, chloramphenicol, oxacillin, ceftriaxone and meropenem were conducted with and without the addition of dexamethasone. The effect of all drugs was abrogated by dexamethasone in their MIC, MBC, and MBEC, except gentamicin and meropenem, for which the MBC was not affected in some strains. The present study opens doors for more investigations on in vitro and in vivo effects and safety of the combination of antimicrobials and glucocorticoids.

Pseudomonas aeruginosa is an important pathogen in opportunistic infections in humans. The increased incidence of antimicrobial-resistant P. aeruginosa isolates has highlighted the need for novel and more potent therapies against this microorganism. Annona glabra is known for presenting different compounds with diverse biological activities, such as anti-tumor and immunomodulatory activities. Although other species of the family display antimicrobial actions, this has not yet been reported for A. glabra . Here, we investigated the antimicrobial activity of the ethyl acetate fraction (EAF) obtained from the leaf hydroalcoholic extract of A. glabra . EAF was bactericidal against different strains of P. aeruginosa . EAF also presented with a time- and concentration-dependent effect on P. aeruginosa viability. Testing of different EAF sub-fractions showed that the sub-fraction 32-33 (SF32-33) was the most effective against P. aeruginosa . Analysis of the chemical constituents of SF32-33 demonstrated a high content of flavonoids. Incubation of this active sub-fraction with P. aeruginosa ATCC 27983 triggered an endothermic reaction, which was accompanied by an increased electric charge, suggesting a high binding of SF32-33 compounds to bacterial cell walls. Collectively, our results suggest that A. glabra -derived compounds, especially flavonoids, may be useful for treating infections caused by P. aeruginosa .

Background: Because of the inherent immunosuppression of cancer patients opportunistic infections by Candida spp, occur frequently. This study aimed to identify Candida species in the oral mucosa of 59 patients with orogastric cancer (OGC) and to analyze the immunological phenotype of these patients., Methods: The yeasts were identified by MALDI-TOF mass spectrometry (MS). For all isolates, we performed phospholipases and proteinases assays, in vitro adherence to buccal epithelial cells (BEC), minimum inhibitory concentration of antifungal drugs and determined the cytokine profile by Cytometric Bead Array flow citometry assay., Results: C. albicans was the most prevalent species in OGC patients (51.6 %) and control group (66.7 %). Candida spp. strains isolated from OGC patients exhibited better adherence to BEC (p = 0.05) than did the control group. Phospholipases production by Candida strains from OGC patients was lower (51.6 %) than in the control group (61.9 %). Proteinases were detected in 41.9 % and 4.8 % of the yeasts from OGC patients and control group, respectively. Significant differences were found in the serum of OGC patients compared to the control group for IL-2, IL-10, TNF-α, IFN-γ and IL-17., Conclusions: The results of this work suggest increased virulence of yeasts isolated from OGC patients and, that this may interfere with the immune phenotype.