Extreme conditions and the availability of determinate substrates in oil fields promote the growth of a specific microbiome. Sulfate-reducing bacteria (SRB) and acid-producing bacteria (APB) are ...usually found in these places and can harm important processes due to increases in corrosion rates, biofouling and reservoir biosouring. Biocides such as glutaraldehyde, dibromo-nitrilopropionamide (DBNPA), tetrakis (hydroxymethyl) phosphonium sulfate (THPS) and alkyl dimethyl benzyl ammonium chloride (ADBAC) are commonly used in oil fields to mitigate uncontrolled microbial growth. The aim of this work was to evaluate the differences among microbiome compositions and their resistance to standard biocides in four different Brazilian produced water samples, two from a Southeast Brazil offshore oil field and two from different Northeast Brazil onshore oil fields. Microbiome evaluations were carried out through 16S rRNA amplicon sequencing. To evaluate the biocidal resistance, the Minimum Inhibitory Concentration (MIC) of the standard biocides were analyzed using enriched consortia of SRB and APB from the produced water samples. The data showed important differences in terms of taxonomy but similar functional characterization, indicating the high diversity of the microbiomes. The APB and SRB consortia demonstrated varying resistance levels against the biocides. These results will help to customize biocidal treatments in oil fields.
Human skin banks around the world face a serious problem with the high number of allogeneic skins that are discarded and cannot be used for grafting due to persistent bacterial contamination even ...after antibiotic treatment. The biofilm formation capacity of these microorganisms may contribute to the antibiotic tolerance; however, this is not yet widely discussed in the literature. Thisstudy analyzed bacterial strains isolated from allogeneic human skin samples,which were obtained from a hospital skin bank that had already been discardeddue to microbial contamination. Biofilm formation and susceptibility topenicillin, tetracycline, and gentamicin were evaluated by crystal violetbiomass quantification and determination of the minimum inhibitoryconcentration (MIC), minimum biofilm inhibitory concentration (MBIC), andminimum biofilm eradication concentration (MBEC) by the broth microdilutionmethod with resazurin dye. A total of 216 bacterial strains were evaluated, and204 (94.45%) of them were classified as biofilm formers with varying degrees ofadhesion. MBICs were at least 512 times higher than MICs, and MBECs were atleast 512 times higher than MBICs. Thus, the presence of biofilm in allogeneicskin likely contributes to the inefficiency of the applied treatments as antibiotictolerance is known to be much higher when bacteria are in the biofilmconformation. Thus, antibiotic treatment protocols in skin banks shouldconsider biofilm formation and should include compounds with antibiofilmaction.
The main sulfate-reducing (SRB) and sulfur-oxidizing bacteria (SOB) in six wastewater treatment plants (WWTPs) located at southern Brazil were described based on high-throughput sequencing of the 16S ...rDNA. Specific taxa of SRB and SOB were correlated with some abiotic factors, such as the source of the wastewater, oxygen content, sample type, and physical chemical attributes of these WWTPs. When the 22 families of SRB and SOB were clustered together, the samples presented a striking distribution, demonstrating grouping patterns according to the sample type. For SOB, the most abundant families were
Spirochaetaceae
,
Chromatiaceae
,
Helicobacteriaceae
,
Rhodospirillaceae
, and
Neisseriaceae
, whereas, for SRB, were
Syntrophaceae
,
Desulfobacteraceae
,
Nitrospiraceae
, and
Desulfovibriaceae
. The structure and composition of the major families related to the sulfur cycle were also influenced by six chemical attributes (sulfur, potassium, zinc, manganese, phosphorus, and nitrogen). Sulfur was the chemical attribute that most influenced the variation of bacterial communities in the WWTPs (
λ
= 0.14,
p
= 0.008). The OTUs affiliated to
Syntrophus
showed the highest response to the increase of total sulfur. All these findings can contribute to improve the understanding in relation to the sulfur-oxidizing and sulfate-reducing communities in WWTPs aiming to reduce H
2
S emissions.
This work reports a new method to obtain polypropylene/titanium dioxide (PP/TiO2) films with antibacterial activity through the in situ synthesis of nanostructured TiO2 directly in the polymer ...solution. In order to compare the performance of the different types of particles, TiO2 particles were also prepared utilizing the sol-gel method and subsequently incorporated into the polymer to form PP/TiO2 films. The obtained TiO2 and PP/TiO2 films were characterized by X-ray diffraction (XRD), dispersive scanning electron microscopy with dispersive energy (SEM/EDS), Brunauer-Emmett-Teller (BET) method, and contact angle. The properties of the particles and the PP/TiO2 films were correlated to the antibacterial activity against Gram-positive (Listeria monocytogenes and Staphylococcus aureus) and Gram-negative (Salmonella typhimurium and Escherichia coli) bacteria. The TiO2 nanostructured obtained in situ presented small particle size (7.7 nm), high surface area (159.8 m2.g-1) and high crystallinity (even without heat treatment), presenting a mixture of anatase and rutile phases, which together exert a beneficial synergistic effect on the antibacterial properties of the TiO2 particles. Experimental results showed a reduction of around 90% of the bacterial population. In situ method showed to be the simplest way to obtain PP/TiO2 films in a single step, which can be used in manufacturing active packaging with antibacterial action for both Gram-positive and Gram-negative bacteria.
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•Preparation of antibacterial PP/TiO2 by the in situ method.•TiO2 nanosized has small particle size, high surface area, and crystallinity.•Anatase and rutile exert a synergistic effect on the antibacterial activity.•The in situ method is the most simple route to obtain PP/TiO2 films in a single step.•TiO2 obtained has antibacterial action for Gram-positive and Gram-negative bacteria.
Many studies have reported the presence of antibiotic-resistant
Pseudomonas aeruginosa in environmental samples such as hospital wastewater and surface water. The present study evaluated the ...contribution of untreated hospital wastewater to the dissemination of resistant
P. aeruginosa strains in aquatic environments, through the analysis of their antibiotic susceptibility profile and genetic similarity. Wastewater samples were collected from two hospitals located in Rio Grande do Sul, RS, Brazil. Superficial water samples were collected from water bodies that received this wastewater discharge. The antibiotic susceptibility profiles of the strains were determined using the disk-diffusion technique and their genotyping was done by amplification of the Enterobacterial Repetitive Intergenic Consensus sequences (ERIC-PCR). The antibiotic resistance was higher among the hospital wastewater strains and the multiresistant phenotype was also observed only among these strains. The ERIC-PCR profiles did not reveal any genetic similarity among the
P. aeruginosa strains from the wastewater and superficial water samples. On the contrary, they showed that genetically distinct populations were established in these different environments and probably that some other contamination source could be contributing to the presence of resistant strains in these water bodies.
The aim of this study was to compare the antimicrobial action of commercially available multipurpose disinfection solutions (MPDS) with and without hydrogel contact lens for disinfection of isolated ...corneal bacteria.
Five commercially available MPDS in Brazil (BioSoak, Clear Lens, OPTI-FREE, Renu, and UltraSept) were tested against Pseudomonas aeruginosa , Staphylococcus aureus , and Staphylococcus epidermidis . All five MPDS were also tested on P. aeruginosa and S. aureus biofilm in a Hioxifilcon A lens.
OPTI-FREE and Renu were effective against all bacterial isolates without contact lenses. BioSoak was effective in inhibiting P. aeruginosa and S. epidermidis but not against S. aureus . UltraSept was effective for inhibiting S. epidermidis and S. aureus but not against P. aeruginosa . Clear Lens was effective in inhibiting only S. epidermidis but not P. aeruginosa and S. aureus . In contact lens bacterial biofilms, OPTI-FREE was the only MPDS to demonstrate significantly higher disinfection.
MPDS containing dual biocides polyquaternium-1 and myristamidopropyl dimethylamine possess the highest disinfection action against multiple ocular pathogens with and without contact lenses when compared with other MPDS. Current single-action polyhexamethylene biguanide solutions are not entirely effective and should not be recommended.
Antimicrobial resistance (AMR) is currently discussed as an important issue worldwide, and the presence of antimicrobial residues (ARs) and antimicrobial resistance genes (ARGs) in the environment, ...especially in the water sources, is a challenge for public health. This study was conducted to evaluate the occurrence and diversity of AR and ARG in water sources from an urban center, in Southern Brazil. A total of thirty-two water samples from drinking water treatment plants (24) and sewage systems (8) were collected during two annual samplings, winter and summer. The PCR was performed by 18 ARGs, and the detection of 47 ARs was performed by LC–MS/MS. All sewage samples presented carbapenemases, ESBL, and
mcr-1
genes as well as quinolones and sulfamethoxazole residues. In drinking water, we just detected
bla
TEM
and
tetB
genes and doxycycline residues in samples before treatment. This study provides data about AR and ARG in drinking water and sewage systems showing that these sources are important reservoirs of both. The limited effectiveness of wastewater treatment processes to remove mainly AR demonstrates the need to implement better protocols of disinfection, in order to limit the spread of AMR in the environment.
Mosquitoes are important vectors of pathogens due to their blood feeding behavior. Aedes aegypti (Diptera: Culicidae) transmits arboviruses, such as dengue, Zika, and Chikungunya. This species ...carries several bacteria that may be beneficial for its biological and physiological development. Therefore, studying the response of its microbiota to chemical products could result in vector control. Recently, imidazolium salts (IS) were identified as effective Ae. aegypti larvicides. Considering the importance of the mosquito microbiota, this study addressed the influence of IS on the bacteria of Ae. aegypti larvae. After exposition of larvae to different IS concentrations, the cultured microbiota was identified through culturomics and mass spectrometry, and the non-cultivated microbiota was characterized by molecular markers. In addition, the influence of the IS on axenic larvae was studied for comparison. There was an alteration in both cultivable species and in their diversity, including modifications in bacterial communities. The axenic larvae were less susceptible to the IS, which was increased after exposing these larvae to bacteria of laboratory breeding water. This highlights the importance of understanding the role of the larval microbiota of Ae. aegypti in the development of imidazolium salt-based larvicides. Such effect of IS towards microbiota of Ae. aegypti larvae, through their antimicrobial action, increases their larvicidal potential.
Bacterial contamination remains the major problem in skin banks, even after antimicrobial treatment, and results in high rates of tissue discarding. This study aimed to analyze bacterial ...contamination in 32 human skin allografts from the skin bank of Dr. Roberto Corrêa Chem from the Hospital Complex Santa Casa de Misericórdia de Porto Alegre. These samples were already discarded due to microbial contamination. The identification of the bacteria isolated from skin allografts was performed by matrix assisted laser desorption ionization-time of flight. The antimicrobial susceptibility of the isolates to six different classes of antimicrobials was determined using the disk-diffusion agar method, and the evaluation of the inhibitory potential was determined by the minimal inhibitory concentration (50/90) of antimicrobials already used in the skin bank and those that most isolates were susceptible to.
A total of 21 (65.6%) skin samples were contaminated with Gram-positive bacteria: 1 (4.7%) with Paenibacillus sp., 12 (61.9%) with Bacillus sp., 6 (28.5%) with Staphylococcus sp., and 2 (9.5%) with Bacillus sp. and Staphylococcus sp. Several resistance profiles, including multiresistance, were found among the isolates. Most of the isolates were susceptible to at least one of the antimicrobials used in the skin bank. All isolates were susceptible to amikacin, gentamicin, and tetracycline, which demonstrated the best inhibitory activities against the isolates and were considered as potential candidates for new antimicrobial treatments.
Bacillus, Paenibacillus, and Staphylococcus were isolated from the skin allografts, thus demonstrating the predominance of Gram-positive bacteria contamination. Other factors not related to the resistance phenotype may also be involved in the persistence of bacterial isolates in the skin allografts after antibiotic treatment. Gentamicin, amikacin, and tetracycline can be considered as an option for a more effective treatment cocktail.
The genus
Pseudomonas
mainly includes opportunistic pathogens that rely on type IV pili as an important virulence factor, which is associated with adherence and biofilm formation.
Pseudomonas
...infections are well known to be persistent and resilient in nature largely because of the tendency of the species to form biofilms. This study aimed at analyzing environmental strains of
Pseudomonas
genus with respect to their ability to execute twitching and swarming motilities as well as with respect to their ability to form biofilms both in the presence as well as in the absence of furanone, a substance that has the potential to prevent the formation of biofilms. Strains of
Pseudomonas aeruginosa
and strains belonging to other species of the genus were analyzed. Twitching and swarming motility assays and biofilm-formation assays, both in the presence as well as in the absence of furanone, were performed. In twitching assay strains belonging to
P. aeruginosa
outperformed those belonging to other species. Interestingly, it was seen that the presence of furanone had a negative impact on formation of twitching and swarming motility zones. In the case of biofilm assays, it was observed that the presence of furanone resulted in an observable decrease in the degree of adhesion in 30% of the analyzed strains. Thus, from our results, it can be concluded that, as compared to other species, the strains belonging to
P. aeruginosa
exhibit a higher potential for twitching motility and similar performance in swarming motility and biofilm formation. It can also be concluded that furanone has the potential to interfere with both motilities as well as with biofilm formation.
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