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Introduction: Serratia marcescens is an opportunistic pathogen found ubiquitously in the environment and associated with a wide range of nosocomial infections. This multidrug-resistant bacterium has been a cause of concern for hospitals and healthcare facilities due to its ability to spread rapidly and cause outbreaks. Next generation sequencing genotyping of bacterial isolates has proven to be a valuable tool for tracking the spread and transmission of nosocomial infections. This has allowed for the identification of outbreaks and transmission chains, as well as determining whether cases are due to endogenous or exogenous sources. Evidence of nosocomial transmission has been gathered through genotyping methods. The aim of this study was to investigate the genetic diversity of carbapenemase-producing S. marcescens in an outbreak at a public hospital in Cuiaba, MT, Brazil. Methodology: Ten isolates of S. marcenses were sequenced and antibiotic resistance profiles analyzed over 12 days. Results: The isolates were clonal and multidrug resistant. Gentamycin and tigecycline had sensitivity in 90% and 80% isolates, respectively. Genomic analysis identified several genes that encode β-lactamases, aminoglycoside-modifying enzymes, efflux pumps, and other virulence factors. Conclusions: Systematic surveillance is crucial in monitoring the evolution of S. marcescens genotypes, as it can lead to early detection and prevention of outbreaks. [ABSTRACT FROM AUTHOR]

This study analyzed the antifungal potential of 16 bacterial strains isolated from mangrove sediment. Bacterial selection was conducted in a solid medium. This was followed by the production and extraction of metabolites using ethyl acetate to evaluate chitinase production, antifungal activity, and toxicity toward Allium cepa and Tenebrio molitor. Bacterial strains B8, B11, and B13 produced the largest inhibition halos (>30 mm) toward Fusarium solani, Fusarium oxysporum, and Rhizoctonia solani fungi. Strains B1, B3, B6, B8, B11, B13, B14, and B16 produced chitinases. In assays using liquid media, B8 and B13 produced the largest inhibition halos. Exposing the fungal inocula to metabolic extracts of strains B6, B8, B11, B13, B14, B15, and B16 caused micromorphological alterations in the inocula, culminating in the inhibition of R. solani sporulation and spore germination. Toxicity tests using Allium cepa and Tenebrio molitor revealed that the metabolites showed low toxicity. Six of the bacterial strains were molecularly identified to species levels, and a further two to genus level. These included Serratia marcescens (B8), which exhibited activity in all tests. Mangroves provide a useful resource for the isolation of microorganisms for biocontrol. Among the isolates, Serratia marcescens and Bacillus spp. showed the greatest potential to produce metabolites for use as biocontrol agents in agriculture. [ABSTRACT FROM AUTHOR]

Bioindicator species are used to assess the damage and magnitude of possible impacts of anthropic origin on the environment, such as the reckless consumption of antimicrobials. Chelonia mydas has several characteristics that make it a suitable bioindicator of marine pollution and of the presence of pathogens that cause diseases in humans. This study aimed to investigate the green sea turtle as a reservoir of resistant bacteria, mainly because C. mydas is the most frequent sea turtle species in Brazilian coastal regions and, consequently, under the intense impact of anthropic factors. Free-living green sea turtles ranging from 42.8 to 92 cm (average = 60.7 cm) were captured from Itaipú Beach, Brazil. Cloaca samples (characterizing the gastrointestinal tract) and neck samples (representing the transient microbiota) were collected. Bacterial species were identified, and their was resistance associated with the antimicrobials cephalothin, ciprofloxacin, gentamicin, tetracycline, and vancomycin. Citrobacter braaki, Klebsiella oxytoca, K. variicola and Proteus mirabilis were found resistant to cephalothin and Morganella morganii and Enterococcus faecalis tetracycline-resistant isolates in cloaca samples. In neck samples, species resistant to tetracycline were Salmonella sp., Serratia marcescens, S. ureylitica and Proteus mirabilis. This data reinforces that the green turtle is a bioindicator of antimicrobial resistance (AMR). [ABSTRACT FROM AUTHOR]

Paratransgenesis consists of genetically engineering an insect symbiont to control vector-borne diseases. Biosafety assessments are a prerequisite for the use of genetically modified organisms (GMOs). Assessments rely on the measurement of the possible impacts of GMOs on different organisms, including beneficial organisms, such as pollinators. The bacterium Serratia AS1 has been genetically modified to express anti-Plasmodium effector proteins and does not impose a fitness cost on mosquitoes that carry it. In the present study, we assessed the impact of this bacterium on the native bee Partamona helleri (Meliponini), an ecologically important species in Brazil. Serratia eGFP AS1 (recombinant strain) or a wild strain of Serratia marcescens were suspended in a sucrose solution and fed to foragers, followed by measurements of survival, feeding rate, and behavior (walking and flying). These bacteria did not change any of the variables measured at 24, 72, and 144 h after the onset of the experiment. Recombinant and wild bacteria were detected in the homogenates of digestive tract during the 144 h period analyzed, but their numbers decreased with time. The recombinant strain was detected in the midgut at 24 h and in the hindgut at 72 h and 144 h after the onset of the experiment under the fluorescent microscope. As reported for mosquitoes, Serratia eGFP AS1 did not compromise the foragers of P. helleri, an ecologically relevant bee. [ABSTRACT FROM AUTHOR]

Bamboos (Bambusoideae, Poaceae) are multiple-purpose perennial grasses, which display a growing production chain in Brazil. One of the main bottlenecks is high-quality supplying of plantlets, then requiring efficient mass propagation methods, such as micropropagation. Contamination by microorganisms is recurrent in bamboo in vitro cultures, although some of those manifestations are considered endophytes harboring plant growth promotion potential. The isolation of endophytic bacteria from in vitro cultures of Dendrocalamus asper and Bambusa oldhamii was performed to assess their potential growth-promoting effect in co-cultivation with in vitro plants of Guadua chacoensis, an economically promising bamboo species. Among the total bacterial collection (32 isolates), all of them showed growth-promotion potential as indole compounds-producers. Sequences of 16S rRNA genes from eight selected isolates were newly generated, and the BLASTn similarity test recovered four bacterial genera (Bacillus, Brevibacillus, Serratia, and Atlantibacter) and six species. The co-cultivation experiment was carried out with three isolates selected based on their low- (Ba16), medium- (Ba03), and high-yield (Ba24) production of indole compounds, and Bayesian inferences strongly supported them as Bacillus subtilis, Serratia marcescens, and Brevibacillus parabrevis, respectively. The co-cultivation with three bacterial isolates, and their dilution levels, did not influence shoot or root growth and, however, did not cause apparent impairment for G. chacoensis in vitro cultures. Taken together, the isolation of endophytic microorganisms from field-growth bamboo clump and its co-cultivation with in vitro cultures of bamboos is possible, encouraging a continuous discovery and improvement of micropropagation techniques. [ABSTRACT FROM AUTHOR]

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• The presence of 16S rRNA methyltranferases in carbapenemase-producing Enterobacterales (CPE) is important to understand the mechanism of resistance in this area and possible dissemination in the country and world. • From 499 CPE, 67 nonclonal and nonsusceptible plazomicin isolates, and 54 encoded 16S-RMTase genes (41 rmtB1 , 7 armA , 3 rmtD2 , 1 rmtD1 and 2 rmtC). Among 41 samples rmtB1 positive, 40 co-harbored blaKPC-2 and 1 blaOXA-48 gene. • The co-existence of 16S-RMTase and CPE is worrisome because of limited treatment options and the endemic characteristic of KPC and NDM. Despite low rates of susceptibility to amikacin and gentamicin, plazomicin could be an important therapeutic option for CPE. Background: The presence of 16S rRNA methyltranferases (16S-RMTases) in carbapenemase-producing Enterobacterales (CPE) is a major concern because it inactivates all clinical use of aminoglycosides, including plazomicin. The aim of this study is to investigate the prevalence of 16S-RMTases in CPE nonsusceptible to plazomicin collected in different Brazilian hospitals. Methods: All isolates with plazomicin MIC ≥ 4 µg/mL (n = 67) were screened for the presence of 16S-RMTases by sequencing. Results: 54 (80.6%) isolates encoded 16S-RMTase genes (41 rmtB1 , 7 armA , 3 rmtD2 , 1 rmtD1 and 2 rmtC). Among 41 samples rmtB1 positive, 40 co-harbored bla KPC-2 and 1 bla OXA-48 gene. Of the seven isolates harboring armA gene, 6 were New Delhi Metallo-beta-lactamase (NDM)-producer. rmtD was only found in isolates Klebsiella pneumoniae Carbapenemase (KPC)-producers, one in Serratia marcescens with rmtD2 , not reported in Brazil. Conclusion : The co-existence of 16S-RMTase and CPE is worrisome because of limited treatment options and the endemic characteristic of (KPC) and NDM in Brazil. [ABSTRACT FROM AUTHOR]

The intrinsic polymyxin resistance displayed by Serratia marcescens makes the acquisition of carbapenemase encoding genes a worrisome event. This study report a SME-4-producing S. marcescens isolate causing septic shock in Brazil. The insertion of novel resistance determinants and their consequent spread in our territory is noteworthy. [ABSTRACT FROM AUTHOR]