Saturated Iso-Type Fatty Acids from the Marine Bacterium Mesoflavibacter zeaxanthinifaciens with Anti-Trypanosomal Potential.

Chagas disease is a Neglected Tropical Disease with limited and ineffective therapy. In a search for new anti-trypanosomal compounds, we investigated the potential of the metabolites from the bacteria living in the corals and sediments of the southeastern Brazilian coast. Three corals, Tubastraea coccinea, Mussismilia hispida, Madracis decactis, and sediments yielded 11 bacterial strains that were fully identified by MALDI-ToF/MS or gene sequencing, resulting in six genera-Vibrio, Shewanella, Mesoflavibacter, Halomonas, Bacillus, and Alteromonas. To conduct this study, EtOAc extracts were prepared and tested against Trypanosoma cruzi. The crude extracts showed IC50 values ranging from 15 to 51 µg/mL against the trypomastigotes. The bacterium Mesoflavibacter zeaxanthinifaciens was selected for fractionation, resulting in an active fraction (FII) with IC50 values of 17.7 µg/mL and 23.8 µg/mL against the trypomastigotes and amastigotes, respectively, with neither mammalian cytotoxicity nor hemolytic activity. Using an NMR and ESI-HRMS analysis, the FII revealed the presence of unsaturated iso-type fatty acids. Its lethal action was investigated, leading to a protein spectral profile of the parasite altered after treatment. The FII also induced a rapid permeabilization of the plasma membrane of the parasite, leading to cell death. These findings demonstrate that these unsaturated iso-type fatty acids are possible new hits against T. cruzi.

Genomic characterization of New Delhi metallo-beta-lactamase-producing species of Morganellaceae, Yersiniaceae, and Enterobacteriaceae (other than Klebsiella) from Brazil over 2013-2022.

Over the last decade, New Delhi metallo-beta-lactamase (NDM) carbapenemase has silently spread in Brazil. In this study, we analyzed a large collection of Enterobacterales other than Klebsiella spp. received in our reference laboratory between 2013 and 2022. A total of 32 clinical isolates displaying different pulsed-field gel electrophoresis profiles, and represented by 11 species in the families Enterobacteriaceae (Citrobacter freundii, Citrobacter portucalensis, Enterobacter hormaechei, and Escherichia coli), Morganellaceae (Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, and Raoultella ornithinolytica), and Yersiniaceae (Serratia marcescens) had their whole genomes sequenced and further analyzed. Antimicrobial susceptibility was determined by disk diffusion, except for polymyxin B, assessed by broth microdilution. The blaNDM-1 allele was predominant (n = 29), but blaNDM-5 was identified in an E. coli specimen with a novel ST, and the blaNDM-7 allele was found in E. hormaechei ST45 and E. coli ST1049. Polymyxin was active against all but one Enterobacteriaceae isolate: an mcr-1-producing E. coli presenting minimal inhibitory concentration (4 mg/L). Isolates producing extended-spectrum ß-lactamases were common: cefotaximase from Munich (CTX-M)-15 (n = 10), CTX-M-2 (n = 4), and CTX-M-8 (n = 3) were detected, and the mcr-1-producing E. coli was found to co-produce both CTX-M-8 and CTX-M-55 ß-lactamases. The mcr-9 gene was found in 5/8 E. hormaechei isolates, distributed in four different sequence types, all of them presenting susceptibility to polymyxin. This study showed that NDM-producing Enterobacterales other than Klebsiella are already spread in Brazil, in diversified species, and cocarrying important resistance genes. Prompt detection and effective implementation of measures to prevent further spread are mandatory for mitigating the dissemination of NDM carbapenemase in hospital settings and preserving the already limited antimicrobial therapy options.

Genomic analysis and antimicrobial activity of ß-lactam/ß-lactamase inhibitors and other agents against KPC-producing Klebsiella pneumoniae clinical isolates from Brazilian hospitals.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) are highly disseminated worldwide, and isolates co-resistant to other antimicrobial agents pose a threat to effective antimicrobial therapy. Therefore, evaluation of novel antimicrobial drugs is needed to identify potential treatments with better outcomes. We evaluated the in vitro activity of novel antimicrobial drugs/combinations against 97 KPC-producing Klebsiella pneumoniae isolates recovered from different hospitals in Brazil during 2021-2022. Clonality, resistance and virulence genes were detected by whole-genome sequencing. The majority of the isolates (54.6%) were classified as extensively drug resistant or multidrug resistant (44.3%); one isolate showed a pandrug resistance phenotype. The most active antimicrobial agents were meropenem-vaborbactam, cefiderocol, and ceftazidime-avibactam, with sensitivities higher than 90%; resistance to ceftazidime-avibactam was associated with KPC-33 or KPC-44 variants. Colistin and polymyxin B were active against 58.6% of the isolates. The 97 isolates were distributed into 17 different sequence types, with a predominance of ST11 (37.4%). Although high in vitro susceptibility rates were detected for meropenem-vaborbactam and cefiderocol, only ceftazidime-avibactam is currently available in Brazil. Our findings showed limited susceptibility to antimicrobial drugs employed for infection treatment of carbapenem-resistant K. pneumoniae, underscoring the urgent need for stringent policies for antimicrobial stewardship to preserve the activity of such drugs.

Genomics and Antimicrobial Susceptibility of Clinical Pseudomonas aeruginosa Isolates from Hospitals in Brazil.

Pseudomonas aeruginosa, an opportunistic pathogen causing infections in immunocompromised patients, usually shows pronounced antimicrobial resistance. In recent years, the frequency of carbapenemases in P. aeruginosa has decreased, which allows use of new beta-lactams/combinations in antimicrobial therapy. Therefore, the in vitro evaluation of these drugs in contemporary isolates is warranted. We evaluated the antimicrobial susceptibility and genomic aspects of 119 clinical P. aeruginosa isolates from 24 different hospitals in Brazil in 2021-2022. Identification was performed via MALDI-TOF-MS, and antimicrobial susceptibility was identified through broth microdilution, gradient tests, or disk diffusion. Whole-genome sequencing was carried out using NextSeq equipment. The most active drug was cefiderocol (100%), followed by ceftazidime-avibactam (94.1%), ceftolozane-tazobactam (92.4%), and imipenem-relebactam (81.5%). Imipenem susceptibility was detected in 59 isolates (49.6%), and the most active aminoglycoside was tobramycin, to which 99 (83.2%) isolates were susceptible. Seventy-one different sequence types (STs) were detected, including twelve new STs described herein. The acquired resistance genes blaCTX-M-2 and blaKPC-2 were identified in ten (8.4%) and two (1.7%) isolates, respectively. Several virulence genes (exoSTUY, toxA, aprA, lasA/B, plcH) were also identified. We found that new antimicrobials are effective against the diverse P. aeruginosa population that has been circulating in Brazilian hospitals in recent years.

Genomic characterization of new Delhi metallo-beta-lactamase-producing species of Morganellaceae, Yersiniaceae, and Enterobacteriaceae (other than Klebsiella) from Brazil over 2013-2022

Over the last decade, New Delhi metallo-beta-lactamase (NDM) carbapenemase has silently spread in Brazil. In this study, we analyzed a large collection of Enterobacterales other than Klebsiella spp. received in our reference laboratory between 2013 and 2022. A total of 32 clinical isolates displaying different pulsed-field gel electrophoresis profiles, and represented by 11 species in the families Enterobacteriaceae (Citrobacter freundii, Citrobacter portucalensis, Enterobacter hormaechei, and Escherichia coli), Morganellaceae (Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, and Raoultella ornithinolytica), and Yersiniaceae (Serratia marcescens) had their whole genomes sequenced and further analyzed. Antimicrobial susceptibility was determined by disk diffusion, except for polymyxin B, assessed by broth microdilution. The blaNDM-1 allele was predominant (n = 29), but blaNDM-5 was identified in an E. coli specimen with a novel ST, and the blaNDM-7 allele was found in E. hormaechei ST45 and E. coli ST1049. Polymyxin was active against all but one Enterobacteriaceae isolate: an mcr-1–producing E. coli presenting minimal inhibitory concentration (4 mg/L). Isolates producing extended-spectrum β-lactamases were common: cefotaximase from Munich (CTX-M)-15 (n = 10), CTX-M-2 (n = 4), and CTX-M-8 (n = 3) were detected, and the mcr-1–producing E. coli was found to co-produce both CTX-M-8 and CTX-M-55 β-lactamases. The mcr-9 gene was found in 5/8 E. hormaechei isolates, distributed in four different sequence types, all of them presenting susceptibility to polymyxin. This study showed that NDM-producing Enterobacterales other than Klebsiella are already spread in Brazil, in diversified species, and cocarrying important resistance genes. Prompt detection and effective implementation of measures to prevent further spread are mandatory for mitigating the dissemination of NDM carbapenemase in hospital settings and preserving the already limited antimicrobial therapy options.

Genomic Diversity of NDM-Producing Klebsiella Species from Brazil, 2013-2022.

Background: Since its first report in the country in 2013, NDM-producing Enterobacterales have been identified in all the Brazilian administrative regions. In this study, we characterized by antimicrobial susceptibility testing and by molecular typing a large collection of NDM-producing Klebsiella isolates from different hospitals in Brazil, mainly from the state of Sao Paulo, over the last decade. Methods: Bacterial isolates positive for blaNDM-genes were identified by MALDI-TOF MS and submitted to antimicrobial susceptibility testing by disk diffusion or broth microdilution (for polymyxin B). All isolates were submitted to pulsed-field gel electrophoresis, and isolates belonging to different clusters were submitted to whole genome sequencing by Illumina technology and downstream analysis. Mating out assays were performed by conjugation, plasmid sizes were determined by S1-PFGE, and plasmid content was investigated by hybrid assembly after MinIon long reads sequencing. Results: A total of 135 NDM-producing Klebsiella were identified, distributed into 107 different pulsotypes; polymyxin B was the only antimicrobial with high activity against 88.9% of the isolates. Fifty-four isolates presenting diversified pulsotypes were distributed in the species K. pneumoniae (70%), K. quasipneumoniae (20%), K. variicola (6%), K. michiganensis (a K. oxytoca Complex species, 2%), and K. aerogenes (2%); blaNDM-1 was the most frequent allele (43/54, 80%). There was a predominance of Clonal Group 258 (ST11 and ST340) encompassing 35% of K. pneumoniae isolates, but another thirty-one different sequence types (ST) were identified, including three described in this study (ST6244 and ST6245 for K. pneumoniae, and ST418 for K. michiganensis). The blaNDM-1 and blaNDM-7 were found to be located into IncF and IncX3 type transferable plasmids, respectively. Conclusions: Both clonal (mainly driven by CG258) and non-clonal expansion of NDM-producing Klebsiella have been occurring in Brazil in different species and clones, associated with different plasmids, since 2013.

Co-production of Classes A and B Carbapenemases BKC-1 and VIM-2 in a Clinical Pseudomonas Putida Group Isolate from Brazil.

Emergence of resistance to classical antimicrobial agents is a public health issue, especially in countries with high antimicrobial consumption rates. Carbapenems have been employed as first-choice option for empirical treatment complicated infections. However, in the last decades, frequency of carbapenemase-producing Gram-negative bacteria has rising, demanding the use of alternative antimicrobial agents. By sequencing the entire genomes with short and long reads technologies, we report the isolation and genomic characterization of a carbapenem-resistant Pseudomonas clinical isolate. The identification based on average nucleotide identity indicates a putative new species into the Pseudomonas putida Group, which carries both the blaBKC-1 and blaVIM-2 carbapenemase genes. The blaBKC-1 was found to be on a transferable IncQ plasmid backbone, whereas blaVIM-2 was found in a new integron, In2126 (intl1∆-blaVIM-2-aacA7-blaVIM-2∆-aacA27-3'CS), described in this study. Our findings indicate that co-occurrence of classes A and B carbapenemase enzymes underscores the evolving emergence of more complex antimicrobial resistance in opportunistic pathogens.

Clonal spread of ArmA- and OXA-23-coproducing Acinetobacter baumannii International Clone 2 in Brazil during the first wave of the COVID-19 pandemic.

Introduction. Carbapenem-resistant Acinetobacter baumannii (CRAB) is the primary pathogen causing hospital-acquired infections. The spread of CRAB is mainly driven by the dissemination of resistant clones, and in Latin America, International Clones IC-1 (also known as clonal complex CC1), IC-4 (CC15) and IC-5 (CC79) are the most prevalent.Gap Statement. There are no documented outbreaks of CRAB International Clone 2 (IC-2) reported in Brazil.Aim. To describe a large outbreak of CRAB caused by the uncommon IC-2 in a Brazilian COVID-19 hospital.Methodology. From May 2020 to May 2021, 224 patients infected or colonized with CRAB were identified in a single hospital; 92 % of them were also infected with SARS-CoV-2. From these patients, 137 isolates were recovered and subjected to antimicrobial susceptibility testing, PCR analysis and molecular typing. Whole-genome sequencing and downstream analysis were carried out on a representative isolate (the first available isolate).Results. In 76 % of the patients, a single OXA-23-producing CRAB IC-2 was identified. All the isolates were susceptible to polymyxin B, but highly resistant (>95 %) to aminoglycosides, fluoroquinolones and beta-lactams. Genomic analysis revealed that the representative isolate also carried the 16S rRNA Methylase ArmA, which was detected for the first time in this species in Brazil.Conclusion. We report the rapid spread of an emerging CRAB clone responsible for causing a large outbreak in a hospital in Brazil, a country with predominance of other CRAB clones. Continuous and prospective surveillance is warranted to evaluate the impact of this clone in Brazilian hospital settings.

Genomic diversity of NDM-producing Klebsiella species from Brazil, 2013-2022

Since its first report in the country in 2013, NDM-producing Enterobacterales have been identified in all the Brazilian administrative regions. In this study, we characterized by antimicrobial susceptibility testing and by molecular typing a large collection of NDM-producing Klebsiella isolates from different hospitals in Brazil, mainly from the state of Sao Paulo, over the last decade. Methods: Bacterial isolates positive for blaNDM-genes were identified by MALDI-TOF MS and submitted to antimicrobial susceptibility testing by disk diffusion or broth microdilution (for polymyxin B). All isolates were submitted to pulsed-field gel electrophoresis, and isolates belonging to different clusters were submitted to whole genome sequencing by Illumina technology and downstream analysis. Mating out assays were performed by conjugation, plasmid sizes were determined by S1-PFGE, and plasmid content was investigated by hybrid assembly after MinIon long reads sequencing. Results: A total of 135 NDM-producing Klebsiella were identified, distributed into 107 different pulsotypes; polymyxin B was the only antimicrobial with high activity against 88.9% of the isolates. Fifty-four isolates presenting diversified pulsotypes were distributed in the species K. pneumoniae (70%), K. quasipneumoniae (20%), K. variicola (6%), K. michiganensis (a K. oxytoca Complex species, 2%), and K. aerogenes (2%); blaNDM-1 was the most frequent allele (43/54, 80%). There was a predominance of Clonal Group 258 (ST11 and ST340) encompassing 35% of K. pneumoniae isolates, but another thirty-one different sequence types (ST) were identified, including three described in this study (ST6244 and ST6245 for K. pneumoniae, and ST418 for K. michiganensis). The blaNDM-1 and blaNDM-7 were found to be located into IncF and IncX3 type transferable plasmids, respectively. Conclusions: Both clonal (mainly driven by CG258) and non-clonal expansion of NDM-producing Klebsiella have been occurring in Brazil in different species and clones, associated with different plasmids, since 2013.

A clinical Pseudomonas chlororaphis isolate harboring a new blaVIM-2 borne integron, In2088, isolated from bloodstream infection in a newborn patient.

We report the isolation and genomic characterization of a VIM-2 producing Pseudomonas chlororaphis causing bloodstream infection in a newborn in Brazil. A new integron, In2088 (intI1-blaVIM-2-aacA7-aacA27-gcu241), was identified and the first P. chlororaphis genome from a clinical isolate was deposited in public databases.

Subinhibitory Concentrations of Biogenic Silver Nanoparticles Affect Motility and Biofilm Formation in Pseudomonas aeruginosa.

Biogenic silver nanoparticles (bio-AgNPs) are increasingly recognized as an antibiofilm and antivirulence strategy against P. aeruginosa, a bacterium that causes chronic infections in immunocompromised and cystic fibrosis patients. This study aimed to investigate the effects of subinhibitory concentrations of bio-AgNPs on motility and biofilm formation in P. aeruginosa. Bio-AgNPs were synthesized via reduction of ionic silver catalyzed by cell-free culture filtrate from Fusarium oxysporum. A total of 17 P. aeruginosa isolates and strains were evaluated for swarming, swimming, and twitching motility in the presence and absence (control) of bio-AgNPs, including 10 clinical isolates from patients with and without cystic fibrosis, 5 environmental isolates obtained from the public water supply system, and 2 reference strains (PAO1 and PA14). Isolates were identified by biochemical and molecular methods. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method. Swarming, swimming, and twitching motility assays were performed in Petri dishes. Biofilm formation capacity was assessed quantitatively by the crystal violet method. MIC values ranged from 15.62 to 62.50 µM. The results showed that subinhibitory concentrations of bio-AgNPs (½ MIC, 7.81-31.25 µM) significantly increased (p < 0.05) swarming, swimming, and twitching motility in 40.0, 40.0, and 46.7% of isolates, respectively. Subinhibitory bio-AgNP treatment enhanced (p < 0.05) biofilm formation capacity in PA14 and a cystic fibrosis isolate (P11). It is concluded that subinhibitory concentrations of bio-AgNPs increased biofilm formation and swarming, swimming, and twitching motility in PA14 and some P. aeruginosa isolates. These virulence factors are directly involved with quorum-sensing systems. Further research should investigate the effects of AgNPs on P. aeruginosa quorum sensing to help elucidate their mechanism of action at subinhibitory concentrations.

Concentrações subinibitórias de nanopartículas de prata sobre as motilidades de pseudomonas aeruginosa isolados de água de abastecimento público / Subinhibitory concentrations of silver nanoparticles on the motility of pseudomonas aeruginosa isolated from public water supply

O uso excessivo e inadequado de antimicrobianos resultou no aumento da resistência bacteriana, especialmente da bactéria Pseudomonas aeruginosa, capaz de expressar diversos fatores de virulência, representando risco ao ambiente e à saúde. Em razão disso, houve um aumento nas pesquisas de nanopartículas metálicas pela sua potencial atividade antimicrobiana. O objetivo deste trabalho foi avaliar o efeito inibitório das nanopartículas de prata biogênicas e a atividade das concentrações subinibitórias sobre as motilidades de P. aeruginosa isolados de água de abastecimento público. Foram selecionados 5 (cinco) isolados para análise das motilidades swarming, swimming e twitching. As nanopartículas de prata biogênicas foram sintetizadas a partir da redução da prata iônica pelo fungo Fusarium oxysporum e apresentaram diâmetro médio de 75 nm. A determinação das concentrações mínimas inibitórias e mínimas bactericidas foram realizadas pelo método de microdiluição em caldo. Para motilidade swarming e swimming as suspensões bacterianas foram inoculadas em superfície do ágar e a zona de motilidade foi medida após incubação a 30ºC/24h. Para motilidade twitching foi realizada inoculação até o fundo da placa, com incubação a 37ºC/24h, seguido da coloração da placa de Petri com cristal violeta 2% por 2h. Todos os isolados foram testados em triplicata em três ocasiões diferentes. Os resultados foram analisados pelo software R Studio (1.2.5001) e valores de p<0,05 foram considerados estatisticamente significantes. Para swarming todos os isolados apresentaram aumento na média do diâmetro após tratamento com concentrações subinibitórias das nanopartículas de prata biogênicas, e somente o isolado identificado como 04010 não alterou a categoria de motilidade, no entanto apresentou diferença estatisticamente significante (p=0,009). Os resultados de swimming também mostraram aumento da expressão deste fator de virulência após tratamento. O isolado 04064 foi o único que mudou de categorização, com aumento significante de 26,1% (p=0,008). Todos os isolados testados para twitching mantiveram a categorização igual ao grupo sem tratamento. No entanto, para os isolados 14021 e 04053 houve aumento significante de 26,0 e 8,2% (p=0,003 e p=0,008, respectivamente). Os resultados deste trabalho mostraram que as nanopartículas de prata biogênicas, em concentrações subinibitórias aumentaram a expressão das motilidades de quase todos os isolados, o que pode sugerir uma resposta à fuga do ambiente desfavorável ocasionado pela presença do composto. Pesquisas complementares sobre as nanopartículas de prata devem ser realizadas, visando a maior compreensão da ação deste composto e de possíveis fatores intrínsecos, como tamanho, formato e rota de síntese da nanopartícula, que podem interferir em sua eficácia.