Emergence of carbapenem-resistant Klebsiella pneumoniae species complex from agrifood systems: detection of ST6326 co-producing KPC-2 and NDM-1.

BACKGROUND: Klebsiella pneumoniae species complex (KpSC) is an important disseminator of carbapenemase-encoding genes, mainly blaKPC-2 and blaNDM-1, from hospitals to the environment. Consequently, carbapenem-resistant strains can be spread through the agrifood system, raising concerns about food safety. This study therefore aimed to isolate carbapenem-resistant KpSC strains from the agricultural and environmental sectors and characterize them using phenotypic, molecular, and genomic analyses. RESULTS: Klebsiella pneumoniae and Klebsiella quasipneumoniae strains isolated from soils used for lemon, guava, and fig cultivation, and from surface waters, displayed an extensive drug-resistance profile and carried blaKPC-2, blaNDM-1, or both. In addition to carbapenemase-encoding genes, KpSC strains harbor a broad resistome (antimicrobial resistance and metal tolerance) and present putative hypervirulence. Soil-derived K. pneumoniae strains were assigned as high-risk clones (ST11 and ST307) and harbored the blaKPC-2 gene associated with Tn4401b and Tn3-like elements on IncN-pST15 and IncX5 plasmids. In surface waters, the coexistence of blaKPC-2 and blaNDM-1 genes was identified in K. pneumoniae ST6326, a new carbapenem-resistant regional Brazilian clone. In this case, blaKPC-2 with Tn4401a isoform and blaNDM-1 associated with a Tn125-like transposon were located on different plasmids. Klebsiella quasipneumoniae ST526 also presented the blaNDM-1 gene associated with a Tn3000 transposon on an IncX3 plasmid. CONCLUSION: These findings provide a warning regarding the transmission of carbapenemase-positive KpSC across the agricultural and environmental sectors, raising critical food safety and environmental issues. © 2024 Society of Chemical Industry.

Genetic diversity of KPC-2-producing Klebsiella pneumoniae complex from aquatic ecosystems.

During the COVID-19 pandemic, the occurrence of carbapenem-resistant Klebsiella pneumoniae increased in human clinical settings worldwide. Impacted by this increase, international high-risk clones harboring carbapenemase-encoding genes have been circulating in different sources, including the environment. The blaKPC gene is the most commonly disseminated carbapenemase-encoding gene worldwide, whose transmission is carried out by different mobile genetic elements. In this study, blaKPC-2-positive Klebsiella pneumoniae complex strains were isolated from different anthropogenically affected aquatic ecosystems and characterized using phenotypic, molecular, and genomic methods. K. pneumoniae complex strains exhibited multidrug-resistant and extensively drug-resistant profiles, spotlighting the resistance to carbapenems, ceftazidime-avibactam, colistin, and tigecycline, which are recognized as last-line antimicrobial treatment options. Molecular analysis showed the presence of several antimicrobial resistance, virulence, and metal tolerance genes. In-depth analysis showed that the blaKPC-2 gene was associated with three different Tn4401 isoforms (i.e., Tn4401a, Tn4401b, and Tn4401i) and NTEKPC elements. Different plasmid replicons were detected and a conjugative IncN-pST15 plasmid harboring the blaKPC-2 gene associated with Tn4401i was highlighted. K. pneumoniae complex strains belonging to international high-risk (e.g., ST11 and ST340) and unusual clones (e.g., ST323, ST526, and ST4216) previously linked to clinical settings. In this context, some clones were reported for the first time in the environmental sector. Therefore, these findings evidence the occurrence of carbapenemase-producing K. pneumoniae complex strains in aquatic ecosystems and contribute to the monitoring of carbapenem resistance worldwide.

Genomic features and comparative analysis of a multidrug-resistant Acinetobacter bereziniae strain infecting an animal: a novel emerging one health pathogen?

Acinetobacter bereziniae has recently gained medical notoriety due to its emergence as a multidrug resistance and healthcare-associated pathogen. In this study, we report the whole-genome characterization of an A. bereziniae strain (A321) recovered from an infected semiaquatic turtle, as well as a comparative analysis of A. bereziniae strains circulating at the human-animal-environment interface. Strain A321 displayed a multidrug resistance profile to medically important antimicrobials, which was supported by a wide resistome. The novel Tn5393m transposon and a qnrB19-bearing ColE1-like plasmid were identified in A321 strain. Novel OXA-229-like ß-lactamases were detected and expression of OXA-931 demonstrated a 2-64-fold increase in the minimum inhibitory concentration for ß-lactam agents. Comparative genomic analysis revealed that most A. bereziniae strains did not carry any antimicrobial resistance genes (ARGs); however, some strains from China, Brazil, and India harbored six or more ARGs. Furthermore, A. bereziniae strains harbored conserved virulence genes. These results add valuable information regarding the spread of ARGs and mobile genetic elements that could be shared not only between A. bereziniae but also by other bacteria of clinical interest. This study also demonstrates that A. bereziniae can spill over from anthropogenic sources into natural environments and subsequently be transmitted to non-human hosts, making this a potential One Health bacteria that require close surveillance.

Citrobacter meridianamericanus sp. nov., isolated from a soil sample.

A Gram-stain-negative strain, designated BR102T, isolated from a soil sample in Brazil was characterized by a polyphasic approach. Comparative 16S rRNA gene sequences indicated that strain BR102T belonged to the genus Citrobacter. The recN- and whole-genome-based phylogeny, and multilocus sequence analysis based on concatenated partial fusA, leuS, pyrG and rpoB sequences strongly supported a clade encompassing strain BR102T and a strain from public database that was distinct from currently recognized species of the genus Citrobacter. Average nucleotide identity and digital DNA-DNA hybridization values between strain BR102T and the closest relative Citrobacter freundii ATCC 8090T were 91.8 and 48.8 %, respectively. The ability to metabolize different compounds further discriminated strain BR102T from other closely related species of the genus Citrobacter. The novel variants bla CMY-179 and qnrB97, which encoded a CMY-2-like ß-lactamase and a QnrB-type protein, respectively, were identified in strain BR102T. BR102T was resistant to ampicillin, amoxicillin/clavulanate and cefoxitin. The DNA G+C content of strain BR102T is 51.3 mol%. Based on these results, strain BR102T represents a novel species of the genus Citrobacter, for which the name Citrobacter meridianamericanus sp. nov. is proposed. The type strain is BR102T (=MUM 22.55T=IMI 507229T).

Patterns of antimicrobial resistance and metal tolerance in environmental Pseudomonas aeruginosa isolates and the genomic characterization of the rare O6/ST900 clone.

Pseudomonas aeruginosa can harbor several virulence and antimicrobial resistance genes (ARGs). In this regard, virulent and multidrug-resistant (MDR) P. aeruginosa strains are closely related to severe infections. In addition, this species can also carry metal tolerance genes, selecting mainly antimicrobial-resistant strains. The action of several pollutants on the environment may favor the occurrence of antimicrobial-resistant and metal-tolerant strains. Therefore, the aim of this study was to characterize potentially pathogenic, antimicrobial-resistant, and/or metal-tolerant P. aeruginosa isolates from different environmental samples (waters, soils, sediments, or sands) and to perform a whole-genome sequence-based analysis of a rare clone from residual water. Environmental isolates carried virulence genes related to adherence, invasion, and toxin production, and 79% of the isolates harbored at least five virulence genes. In addition, the isolates were resistant to different antimicrobials, including important antipseudomonal agents, and 51% of them were classified as MDR, but only ARGs associated with aminoglycoside resistance were found. Furthermore, some isolates were tolerant mainly to copper, cadmium, and zinc, and presented metal tolerance genes related to these compounds. Whole-genome characterization of an isolate with unique phenotype with simultaneous resistance to antimicrobials and metals showed nonsynonymous mutations in different antimicrobial resistance determinants and revealed a classification of O6/ST900 clone as rare, potentially pathogenic, and predisposed to acquire multidrug resistance genes. Therefore, these results draw attention to the dissemination of potentially pathogenic, antimicrobial-resistant, and metal-tolerant P. aeruginosa isolates in environmental niches, alerting to a potential risk mainly to human health.

Occurrence of clinically relevant antimicrobial resistance genes, including mcr-3 and mcr-7.1, in soil and water from a recreation club.

We researched clinically relevant antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs) in environmental samples from a recreation club in Brazil. A total of 172 amplicons (105 from soil and 67 from water) of 26 ARGs (20 among the soil and water samples; four only in soil samples; two only in water samples) were detected. Nine MGEs were detected, including plasmids and class 1 integron. The absolute abundance of the mcr-3 gene ranged from 1.12 × 102 to 1.81 × 103 copies/mL-1 in water samples. The rapid spread of mcr-like genes in several sources has generated a huge concern to public health. Accordingly, understanding of antimicrobial resistance, carry out surveillance studies may contribute to tackle antimicrobial resistance. As the environmental samples were collected from a popular recreation club in Brazil, this study points out to the risk and exposure to clinically relevant ARGs, especially to mcr-3 and mcr-7.1 genes.

Characterization of multidrug-resistant and virulent Klebsiella pneumoniae strains belonging to the high-risk clonal group 258 (CG258) isolated from inpatients in northeastern Brazil.

Multidrug-resistant (MDR) and hypervirulent Klebsiella pneumoniae (hvKp) clones have become a major threat to global public health. The clonal group 258 (CG258) is considered a high-risk CG and the K. pneumoniae strains belonging to it are often multi-resistant and to spread mainly in the hospital environment. This study aimed to characterize the antimicrobial resistance profile, virulence factors, and the clonal relationships among 13 K. pneumoniae strains belonging to CG258 from patients admitted to a tertiary hospital in Teresina, in the state of Piauí, northeastern Brazil. Ten strains were classified as MDR and three as extensively drug-resistant (XDR). Three different ß-lactamase-encoding genes (blaKPC, blaOXA-1-like, and blaCTX-M-Gp1) and six virulence genes (fimH, ycfM, mrkD, entB, ybtS, and kfu) were detected. Moreover, two hypermucoviscous K. pneumoniae strains and one capsular K-type 2 were found. Multilocus sequence typing analysis revealed ten different sequence types (STs) (ST14, ST17, ST20, ST29, ST45, ST101, ST268, ST1800, ST3995, and ST3996) belonging to CG258, being two (ST3995 and ST3996) described for the first time in this study.

Whole-genome sequence-based analysis of the Paenibacillus aquistagni strain DK1, a polyethylene-degrading bacterium isolated from landfill.

Polyethylene-degrading bacteria have been emerging as a rational and safe alternative in bioremediation strategies. In this context, some Paenibacillus species produce enzymes involved in the biodegradation of pollutants. Among the enzymes involved in the biodegradation of polyethylene, the alkane hydroxylases, encoded by alkB homologous genes, play a key role in this process. Therefore, this study aimed to identify and perform a genomic investigation of the first polyethylene-degrading Paenibacillus sp. strain, named DK1. The whole-genome sequence-based analysis revealed that the DK1 strain belonged to the species Paenibacillus aquistagni and shared a total of 4327 CDSs with P. aquistagni strain 11. On the other hand, a comparison of the gene clusters showed that DK1 strain harbored a genetic context surrounding the alkB-like gene similar to that found in Pseudomonas sp. strains. The percentage of similarity ranged from 47.88 to 99.76% among all complete amino acid sequences of AlkB-like proteins analyzed. Nevertheless, the predicted amino acid sequences of AlkB-like contained typical structural motifs of alkane hydroxylases, such as His boxes and the HYG motif. These findings associated with the previously reported phenotypic results highlighted the potential of P. aquistagni strain DK1 to biodegrade polyethylene. Therefore, further studies focusing on the biochemical and structural properties of the AlkB-like protein from Paenibacillus may also contribute to the development of sustainable bioremediation strategies.

Co-occurrence of mcr-1, mcr-3, mcr-7 and clinically relevant antimicrobial resistance genes in environmental and fecal samples.

Multidrug-resistant bacteria harboring different antimicrobial resistance genes (ARGs) have been detected worldwide. The association of plasmid-mediated colistin resistance genes (mcr-like) and other ARGs in bacteria isolated from animals is a huge concern worldwide. Therefore, this study aimed to investigate the presence of mcr-like genes and clinically relevant ARGs as well as plasmids in samples from a zoo. Fecal and environmental (soil and water) samples were collected from a zoo and the DNA of cultivable aerobic bacteria was extracted. ARGs were screened by PCR and the plasmids were detected using the PCR-based replicon typing method. A total of 74 amplicons from 27 ARGs [mcr-1, mcr-3, mcr-7.1, blaCTX-M-Gp1, blaCTX-M-Gp2, blaCTX-M-Gp9, blaVEB, blaPER, blaCMY, tetA, tetB, tetC, aadA, aac(6')-Ib, aph(3')-Ia, ant(2'')-Ia, qnrA, qnrB, qnrS, oqxA, oqxB, sul1, sul2, sul3, cmlA, mefAE, ermB] and 21 amplicons from eight plasmid families (IncY, ColE-like, IncFrepB, IncFIA, IncFIB, IncHI1, IncFIC, IncP) were detected. These findings reinforce that the zoo acts as a reservoir of clinically relevant ARGs, including mcr-like, and call attention to the monitoring studies in the zoo. Therefore, to the best of our knowledge, this is the first report of the world of mcr-1, mcr-3 and mcr-7.1 in environmental samples from the zoo.

Comparative analysis of multidrug resistance plasmids and genetic background of CTX-M-producing Escherichia coli recovered from captive wild animals.

Multiple interlinked factors are associated with the global resistome, whereas multidrug-resistant (MDR) pathogens have been related to increased mortality rates in humans and animals. CTX-M-type is the most prevalent extended-spectrum ß-lactamase (ESBL) among Enterobacteriaceae, which raises concern worldwide. Zoological gardens have a high density of animals that live very close to each other and to humans. Therefore, this study aimed to investigate through the whole-genome sequencing (WGS) MDR Escherichia coli lineages obtained from captivity wild animals in a zoo. Genetic background showed a wide resistome for antimicrobials (e.g., blaCTX-M-65, blaCTX-M-8, blaCMY-2, qnrB19), metals (e.g., pcoABCDERS, silABCEP, merACDEPRT), and antibacterial biocides (e.g., sugE, mdfA) among MDR CTX-M-producing E. coli belonging to CC155 and CC156. Mobilome analysis revealed several plasmids, and eight of them were completely characterized, which showed different backbone-encoding genes. Comparative analysis of plasmids blaCTX-M-65/IncHI2-ST3, blaCTX-M-8/IncI1-ST113, and IncQ1 showed a high identity among plasmids obtained from humans and animals worldwide distributed. Besides, several virulence genes, CRISPR, and prophage-related sequences were also detected. The occurrence of MDR E. coli belonging to CCs closely related to humans and food-producing animals and the high similarity among the plasmids from MDR E. coli carrying clinically significant antimicrobial resistance genes may indicate intercontinental dissemination of these lineages and plasmids. Therefore, these findings contribute to the monitoring of antimicrobial resistance and the human-animal-environment interface worldwide. Key Points • Wide resistome for antimicrobials, metals, and antibacterial biocides. • Multidrug resistance plasmids (blaCTX-M-65/IncHI2-ST3, blaCTX-M-8/IncI1-ST113). • Co-occurrence of plasmid-mediated resistance and virulence genes.

High Level of Resistance to Antimicrobials and Heavy Metals in Multidrug-Resistant Pseudomonas sp. Isolated from Water Sources.

Antimicrobial-resistant bacteria (ARB) carrying antimicrobial resistance genes (ARGs) have been increasingly detected in water sources. Pseudomonas sp. are opportunistic pathogens commonly reported in water samples and different antimicrobial resistance mechanisms have been described in Pseudomonas sp., producing multidrug-resistant (MDR) phenotype. Besides, the presence of heavy metal resistance genes (HMRGs) may select ARB, which is worrying. Therefore, this study aimed to characterize the genotypes of Pseudomonas sp. isolated from different water sources. Water samples (i.e., rivers, streams, lakes and sewage treatment plants) were collected from different cities in Brazil. The bacterial identification was performed by sequencing the 16S rDNA and the resistance profile to antimicrobials and heavy metals were determined by minimum inhibitory concentration (MIC). Several ARGs, HMRGs, and plasmids were researched by PCR and the amplicons were sequenced for confirmation. A total of 23 Pseudomonas sp. isolates were obtained and identified as Pseudomonas saponiphila, Pseudomonas hunanensis, Pseudomonas aeruginosa, and Pseudomonas asiatica. These isolates presented high MICs to antimicrobials and heavy metals, being the great majority (n = 21; 91%) classified as MDR. Different clinically important ARGs were detected, such as blaGES, qnrS, qepA, tetB, aac(3')-IIa, and ant(2″)-Ia. The czcA gene was the only HMRG detected and no plasmids were found. To the best of our knowledge, this is the first report of the world of P. saponiphila carrying ARGs (i.e., blaGES, qnrS, aac(3')-IIa, tetB) and QepA-producing P. hunanensis and the first time of P. saponiphila, P. asiatica, and P. hunanensis in Brazil.

Genomic insights into multidrug-resistant and hypervirulent Klebsiella pneumoniae co-harboring metal resistance genes in aquatic environments.

Klebsiella pneumoniae is one of the most important pathogens related to hospital-acquired infections. The incidence of infections by hypervirulent K. pneumoniae (hvKp), especially community-acquired infections, has been increasing in recent decades. The occurrence of multidrug-resistant (MDR) hvKp has been increasingly reported worldwide decreasing the treatment options, which is a concern. Aquatic environments have been considered a reservoir of MDR pathogens, which contribute to the spread of MDR pathogens. Therefore, this study aimed to characterize MDR-hvKp strains obtained from public aquatic environments using whole genome sequencing in Brazil. Resistome analysis showed ARGs to ß-lactams, quinolones, tetracyclines, sulfonamides, and fosfomycin as well as several metal resistance genes. Virulome analysis showed several virulence genes. Besides, genomic islands, CRISPR and prophage-related sequences were also detected. MLST analysis revealed the presence of two novel sequences types (STs) belonging to different clonal complexes (CCs) [ST4415 (CC515) and ST4416 (CC2654)], and one already described [ST661 (CC661)]. The presence of MDR-hvKp lineages in water sources belonging to STs and CCs associated with humans and animals shows the ability of these pathogens to spread to different aquatic environments. This study reports for the first time two novel STs of MDR-hvKp as well as the presence of a rare ST661 closely related to outbreaks in aquatic environments, and contributes to surveillance studies and MDR-hvKp monitoring worldwide.

A mini-review: current advances in polyethylene biodegradation.

Polyethylene (PE) has been described as the most abundant plastic worldwide since it is used for the manufacture of disposable recipients, such as bottles and bags. Consequently, large quantities of PE have been accumulating in the environment causing serious ecological problems. Although there are numerous plastic disposal methods, each one has its own inherent limitations, but biodegradation seems to be the least harmful method to deal with this type of contaminant. This mini-review summarizes current advances in PE contamination, focusing on the recent findings related to the biodegradation of PE in different environmental conditions, presenting the microorganisms, genes, and enzymes involved, as well as the mechanisms of PE biodegradation. It also attempts to address the main and current biodegradation methods used to minimize the impacts of this polymer on the environment.

Isolation of a polyethylene degrading Paenibacillus sp. from a landfill in Brazil.

The annual production of plastics has doubled over the past 15 years and, consequently, a large amount of plastic has accumulated in the environment generating ecological problems. In this study, a Paenibacillus sp. isolate was obtained from a landfill from Brazil and it presented the alkane hydroxylase gene (alkB). Weight loss of low-density polyethylene (LDPE) was measured and a significant difference in final weight compared to initial weight was assessed. Some chemical characteristics, such as bond scissions and formation of new functional groups [carboxylic acids (3300-2500 cm-1), esters (1210-1163 cm-1), and ethers (1075-1020 cm-1)], were detected by Fourier-transform infrared spectroscopy. Bacterial colonization on the plastic surface and physical changes, as formation of cracks and pits, was visualized by scanning electron microscopy. This isolate was susceptible to all the antimicrobials tested. Therefore, this isolate possesses great potential to degrade polyethylene and become an option for LDPE bioremediation.

Heavy metal resistance genes and plasmid-mediated quinolone resistance genes in Arthrobacter sp. isolated from Brazilian soils.

Arthrobacter sp. are Gram-positive bacilli commonly obtained from soil and in the hospital environment. These species have been reported to cause several types of infection. Heavy metals are a threat to the ecological system due to their high-levels of toxicity and the fluoroquinolones are antimicrobials widely used for the treatment of different bacterial infections. The aim of this study was to investigate the resistance to fluoroquinolone and heavy metals, the presence of plasmid-mediated resistance (PMQR) genes and heavy metals resistance (HMR) genes and the presence of plasmids in Arthrobacter sp. obtained from Brazilian soils. Bacterial isolation was performed using soil samples from different Brazilian regions. The bacterial identification was performed by 16S rRNA gene sequencing. The resistance profile for fluoroquinolones and heavy metals was determined by MIC. Several PMQR and HMR genes and plasmid families were investigated by PCR. Eight isolates were obtained from soil samples from different cultivations and regions of Brazil. All isolates were resistant to all fluoroquinolones, cadmium, cobalt and zinc and the majority to copper. Among the PMQR genes, the qepA (4) was the most prevalent, followed by qnrS (3), qnrB (3), oqxB (2) and oqxA (1). Among the HMR genes, the copA was detected in all isolates and the czcA in two isolates. The replication origin of the ColE-like plasmid was detected in all isolates; however, no plasmid was detected by extraction. The association of resistance to heavy metals and antimicrobials is a threat to the environmental balance and to human health. There are no studies reporting the association of PMQR and HMR genes in bacteria belonging to the genus Arthrobacter. To the best of our knowledge, this is the first report of qnrB, qepA, oqxA and oqxB in Arthrobacter species.

Change in the antimicrobial resistance profile of Pseudomonas aeruginosa from soil after exposure to herbicides.

The extensive use of pesticides represents a risk to human health and to the environment. This study aimed to investigate if the exposure to atrazine and diuron, two herbicides widely used in Brazil, could induce changes in the susceptibility profile to aztreonam, colistin and polymyxin B antimicrobials in isolates of P. aeruginosa obtained from soil samples by using the determination of minimum inhibitory concentration (MIC) test. Three isolates had an increase of MIC to aztreonam after exposure to both herbicides and one isolate did not show any MIC change. The MexAB-OprM efflux pump has already been upregulated in these isolates and the herbicides atrazine and diuron did not increase MexAB-OprM overexpression. Therefore, the decrease in aztreonam susceptibility was not directly related to this pump, suggesting that probably other mechanisms should be involved.

Evaluation of different molecular and phenotypic methods for identification of environmental Burkholderia cepacia complex.

The correct identification of different genera and bacterial species is essential, especially when these bacteria cause infections and appropriate therapies need to be chosen. Bacteria belonging to the Burkholderia cepacia complex are considered important opportunistic pathogens, causing different types of infections in immunocompromised, principally in patients with cystic fibrosis. Twenty-one isolates were obtained from different soil samples and identified by sequencing of 16S rRNA, 23S rRNA, recA gene, MLST and by VITEK 2 and MALDI-TOF MS systems. Then, statistical analyses were performed. VITEK 2 and MALDI-TOF MS systems showed different bacterial genera. Sequencing of the 16S rRNA, 23S rRNA gene and amplification of recA gene showed that all the isolates belong to the B. cepacia complex. Sequencing of the recA gene showed a predominance of B. cenocepacia. The PCR of the recA gene showed a high specificity when it is necessary to identify the bacteria belonging to the B. cepacia complex in comparison with 16S and 23S rRNA genes sequencing. MLST analyzes showed a diversity of STs, which have not yet been correlated to the species. Phenotypic identification was not suitable for the identification of these pathogens since in many cases different genera have been reported, including identification by using MALDI-TOF MS.

Characterization of non-O157 Shiga toxin-producing Escherichia coli (STEC) obtained from feces of sheep in Brazil.

Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens and may induce severe diarrheagenic diseases in humans and other animals. Non-O157 STEC have been emerging as important pathogens causing outbreaks worldwide. Bacterial resistance to antimicrobials has become a global public health problem, which involves different ecological spheres, including animals. This study aimed to characterize the resistance to antimicrobials, plasmids and virulence, as well as the serotypes and phylogenetic groups in E. coli isolated from sheep in Brazil. A total of 57 isolates were obtained and showed different antimicrobial resistance profiles. Nineteen isolates presented acquired antimicrobial resistance genes (ARGs) (blaCTX-M-Gp9, qnrB, qnrS, oqxB, oqxA, tetA, tetB, tetC, sul1 and sul2) and plasmid families (F, FIA, FIB, I1, K, HI1 and ColE-like). The stx1, stx2 and ehxA virulence genes were detected by PCR, being 50 isolates (87.7%) classified as STEC. A great diversity of serotypes was detected, being O176:HNM the most predominant. Phylogenetic group E was the most prevalent, followed by B1, A and B2. To the best of our knowledge, this is the first report in the world of blaCTX-M-Gp9 (O75, O114, O100, O128ac and O176 serogroups), qnrB and oqxB genes in non-O157 STEC in healthy sheep. The results obtained in the present study call attention to the monitoring of antimicrobial-resistant non-O157 STEC harboring acquired ARGs worldwide and indicate a zoonotic risk due to the profile of virulence, resistance and serotype found.

Plasmids associated with heavy metal resistance and herbicide degradation potential in bacterial isolates obtained from two Brazilian regions.

The use of pesticides has been increasing due to the great agricultural production worldwide. The pesticides are used to eradicate pests and weeds; however, these compounds are classified as toxic to non-target organisms. Atrazine and diuron are herbicides widely used to control grassy and broadleaf weeds and weed control in agricultural crops and non-crop areas. Heavy metals are also important environmental contaminants that affect the ecological system. This study aimed to investigate the presence of herbicides-degrading genes and heavy metal resistance genes in bacterial isolates from two different soil samples from two Brazilian regions and to determine the genetic location of these genes. In this study, two isolates were obtained and identified as Escherichia fergusonii and Bacillus sp. Both isolates presented atzA, atzB, atzC, atzD, atzE, atzF, puhA, and copA genes and two plasmids each, being the major with ~ 60 Kb and a smaller with ~ 3.2 Kb. Both isolates presented the atzA-F genes inside the larger plasmid, while the puhA and copA genes were detected in the smaller plasmid. Digestion reactions were performed and showed that the ~ 60-Kb plasmid presented the same restriction profile using different restriction enzymes, suggesting that this plasmid harboring the complete degradation pathway to atrazine was found in both isolates. These results suggest the dispersion of these plasmids and the multi-herbicide degradation potential in both isolates to atrazine and diuron, which are widely used in different culture types worldwide.

Buttiauxella chrysanthemi sp. nov., isolated from a chrysanthemum plantation in Brazil.

A novel Gram-negative, rod-shaped, non-motile bacterium, designated C1BT was isolated from a soil sample of a chrysanthemum plantation in Campinas, Brazil. Strain C1BT formed white colonies on BHI medium, it produces acid from D-lactose, D-mannose, D-arabinose, but does not produce from D-adonitol, m-inositol, D-melibiose, D-raffinose and D-sorbitol and it is negative for lysine and ornithine decarboxylase, phenylalanine deaminase, and citrate. Phylogenetic analysis based on 16S rRNA and rpoB genes sequences showed that strain C1BT has a similarity of 98.2 and 96.8% with different species of Buttiauxella genus. Major fatty acids were C16:0, summed features 4 (C16:1 ω7c and iso-C15:0 2OH), summed features 7 (C18:1 ω7c, C18:1 ω9t, and/or C18:1 ω12t), C17:0 cyclo, summed features 3 (iso-C16:1 I and C14:0 3OH) and C14:0. The mole percent of G+C was 49.6 mol%. Based on these results, a new species Buttiauxella chrysanthemi is proposed. The type strain is C1BT (= CPQBA 1120/15T = CMRVSP5791T).