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Introduction: Acinetobacter baumannii contributes significantly to the global issue of multidrug-resistant (MDR) nosocomial infections. Often, these strains demonstrate resistance to carbapenems (MDR-CRAB), the first-line treatment for infections instigated by MDR A. baumannii. Our study focused on the antimicrobial susceptibility and genomic sequences related to plasmids from 12 clinical isolates of A. baumannii that carry both the blaOXA-58 and bla NDM-1 carbapenemase genes. Methods: Whole-genome sequencing with long-read technology was employed for the characterization of an A. baumannii plasmid that harbors the bla OXA-58 and blaNDM-1 genes. The location of the bla OXA-58 and bla NDM-1 genes was confirmed through Southern blot hybridization assays. Antimicrobial susceptibility tests were conducted, and molecular characterization was performed using PCR and PFGE. Results: Multilocus Sequence Typing analysis revealed considerable genetic diversity among bla OXA-58 and bla NDM-1 positive strains in Brazil. It was confirmed that these genes were located on a plasmid larger than 300 kb in isolates from the same hospital, which also carry other antimicrobial resistance genes. Different genetic contexts were observed for the co-occurrence of these carbapenemase-encoding genes in Brazilian strains. Discussion: The propagation of bla OXA-58 and bla NDM-1 genes on the same plasmid, which also carries other resistance determinants, could potentially lead to the emergence of bacterial strains resistant to multiple classes of antimicrobials. Therefore, the characterization of these strains is of paramount importance for monitoring resistance evolution, curbing their rapid global dissemination, averting outbreaks, and optimizing therapy.
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Carbapenem-resistant Acinetobacter spp. is associated with nosocomial infections in intensive care unit patients, resulting in high mortality. Although Acinetobacter spp. represent a serious public health problem worldwide, there are a few studies related to the presence of carbapenemases in health care facilities and other environmental settings in Ecuador. The main aim of this study was to characterize the carbapenem-resistant Acinetobacter spp. isolates obtained from four hospitals (52) and from five rivers (27) close to Quito. We used the disc diffusion and EDTA sinergy tests to determine the antimicrobial susceptibility and the production of metallo ß-lactamases, respectively. We carried out a multiplex PCR of gyrB gene and the sequencing of partial rpoB gene to bacterial species identification. We performed molecular screening of nine carbapenem-resistant genes (blaSPM, blaSIM, blaGIM, blaGES, blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, and blaOXA-143) by multiplex PCR, followed by identification using sequencing of blaOXA genes. Our findings showed that carbapenem-resistant A. baumannii were the main species found in health care facilities and rivers. Most of the clinical isolates came from respiratory tract samples and harbored blaOXA-23, blaOXA-366, blaOXA-72, blaOXA-65, blaOXA-70, and blaOXA-143-like genes. The river isolates harbored only the blaOXA-51 and probably blaOXA-259 genes. We concluded that the most predominant type of carbapenem genes among isolates were both blaOXA-23 and blaOXA-65 among A. baumannii clinical isolates.
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Infecções por Acinetobacter , Acinetobacter , Proteínas de Bactérias , beta-Lactamases , Equador/epidemiologia , beta-Lactamases/genética , beta-Lactamases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Humanos , Infecções por Acinetobacter/microbiologia , Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter/genética , Acinetobacter/isolamento & purificação , Acinetobacter/efeitos dos fármacos , Acinetobacter/enzimologia , Testes de Sensibilidade Microbiana , Infecção Hospitalar/microbiologia , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Rios/microbiologia , Acinetobacter baumannii/genética , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/enzimologia , Reação em Cadeia da Polimerase MultiplexRESUMO
The discharge of untreated or partially treated wastewater can have detrimental impacts on the quality of water bodies, posing a significant threat to public health and the environment. In Ecuador, previous research indicates a high prevalence of antimicrobial resistant (AMR) bacteria in surface waters affected by human activities, including irrigation channels. In this study, we analyzed sediment samples collected from an irrigation channel utilized for agricultural purposes in northern Ecuador, using microbiological techniques and whole-genome sequencing (WGS). Our investigation revealed the first documented occurrence of E. kobei in Ecuador and the initial report of environmental E. kobei ST2070. Furthermore, we identified the coexistence of OXA-10-type class D ß-lactamase and KPC-2-type class A ß-lactamase in the E. kobei isolate (UTA41), representing the first report of such a phenomenon in this species. Additionally, we detected various antibiotic resistance genes in the E. kobei UTA41 isolate, including blaCTX-M-12, fosA, aac(6')-lb, sul2, msr(E), and mph(A), as well as virulence genes such as bacterial efflux pump and siderophore biosynthesis genes. We also identified two intact prophage regions (Entero_186 and Klebsi_phiKO2) in the isolate. Our study presents the first evidence of E. kobei isolate containing two carbapenemase-encoding genes in environmental samples from Latin America. This finding indicates the potential spread of critical-priority bacteria in water samples originating from anthropogenic sources, such as urban wastewater discharges and livestock facilities.
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Acinetobacter baumannii has been described as a cause of serious community-acquired infections in tropical countries. Currently, its implications when simultaneously identified with other pathogens are not yet adequately understood. A descriptive study was conducted on hospitalized patients with a diagnosis of moderate/severe SARS-CoV-2-induced pneumonia confirmed via real-time RT-PCR. Patients aged > 18 years who were admitted to a specialized COVID-19 treatment center in Peru were selected for enrollment. A. baumannii was detected via the PCR amplification of the blaOXA-51 gene obtained from nasopharyngeal swabs within 48 h of hospitalization. A total of 295 patients with COVID-19 who met the study inclusion criteria were enrolled. A. baumannii was simultaneously identified in 40/295 (13.5%) of COVID-19-hospitalized patients. Demographic data and comorbidities were comparable in both Acinetobacter-positive and -negative subgroups. However, patients identified as being infected with Acinetobacter were more likely to have received outpatient antibiotics prior to hospitalization, had a higher requirement for high-flow nasal cannula and a higher subjective incidence of fatigue, and were more likely to develop Acinetobacter-induced pneumonia during hospitalization. Conclusions: The group in which SARS-CoV-2 and A. baumannii were simultaneously identified had a higher proportion of fatigue, a higher frequency of requiring a high-flow cannula, and a higher proportion of superinfection with the same microorganism during hospitalization.
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BACKGROUND: Acinetobacter baumannii international clone II (IC2) is a widespread pandemic clone, however, it is rarely described in South America. The present study reported an outbreak caused by XDR IC2 strains in a clinical setting in Rio de Janeiro in 2022. METHODS: Molecular epidemiology analysis was conducted with MLST to determine the clonal relationship and to assign a sequence type. The antimicrobial resistance profile of A. baumannii strains was assessed by the disk-diffusion method and MIC determination, and the presence of antibiotic resistance genes was determined by PCR and Sanger sequencing. The whole genome of one representative strain (AB91) was sequenced to prospect its resistome and virulome. RESULTS: The MLST revealed that all strains belonged to the ST2 (Pasteur scheme) that corresponded to the pandemic IC2 lineage. They presented the XDR phenotype, which was compatible with their resistome composed of several acquired resistance genes and altered housekeeping genes. Additionally, an expressive virulome was revealed in AB91 genome. Genomic comparison with the unique other available IC2 genome from Brazil revealed that outbreaks occurring during (São Paulo - 2020/2021) and after (Rio de Janeiro - 2022) COVID-19 pandemics were caused by the same IC2 lineage. CONCLUSIONS: This study suggests that the presence of a huge arsenal of resistance and virulence genes may have contributed to the persistence and the successful establishment of IC2 in Brazilian clinical settings during and after the COVID-19 pandemics in response to a series of events, such as the antibiotic overused during that period.
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Acinetobacter baumannii , COVID-19 , Humanos , Brasil/epidemiologia , Acinetobacter baumannii/genética , Proteína 1 Semelhante a Receptor de Interleucina-1 , Tipagem de Sequências Multilocus , COVID-19/epidemiologia , Surtos de Doenças , Antibacterianos/farmacologia , Carbapenêmicos/farmacologiaRESUMO
BACKGROUND: Carbapenemase production is a global public health threat. Antimicrobial resistance (AMR) data analysis is critical to public health policy. Here we analyzed carbapenemase detection trends using the AMR Brazilian Surveillance Network. METHODS: Carbapenemase detection data from Brazilian hospitals included in the public laboratory information system dataset were evaluated. The detection rate (DR) was defined as carbapenemase detected by gene tested per isolate per year. The temporal trends were estimated using the Prais-Winsten regression model. The impact of COVID-19 on carbapenemase genes in Brazil was determined for the period 2015-2022. Detection pre- (October 2017 to March 2020) and post-pandemic onset (April 2020 to September 2022) was compared using the χ2 test. Analyses were performed with Stata 17.0 (StataCorp, College Station, TX). RESULTS: 83 282 blaKPC and 86 038 blaNDM were tested for all microorganisms. Enterobacterales DR for blaKPC and blaNDM was 68.6% (41 301/60 205) and 14.4% (8377/58 172), respectively. P. aeruginosa DR for blaNDM was 2.5% (313/12 528). An annual percent increase for blaNDM of 41.1% was observed, and a decrease for blaKPC of -4.0% in Enterobacterales, and an annual increase for blaNDM of 71.6% and for blaKPC of 22.2% in P. aeruginosa. From 2020 to 2022, overall increases of 65.2% for Enterobacterales, 77.7% for ABC, and 61.3% for P. aeruginosa were observed in the total isolates. CONCLUSIONS: This study shows the strengths of the AMR Brazilian Surveillance Network with robust data related to carbapenemases in Brazil and the impact of COVID-19 with a change in carbapenemase profiles with blaNDM rising over the years.
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Acinetobacter baumannii , COVID-19 , Humanos , Pseudomonas aeruginosa/genética , Carbapenêmicos/farmacologia , Acinetobacter baumannii/genética , Brasil/epidemiologia , Pandemias , COVID-19/epidemiologia , Proteínas de Bactérias/genética , beta-Lactamases/genética , Plasmídeos , Antibacterianos/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
Acinetobacter baumannii infection presents a high mortality rate and few therapeutic options. This study aimed to evaluate clinical-microbiological characteristics and prognosis factors of patients diagnosed with A. baumanni. infections treated with oral doxycycline. A retrospective cohort of hospitalized patients with confirmed Acinetobacter spp. infection between 2018 and 2020 receives at least 3 days of oral doxycycline. Clinical and microbiological data were evaluated, including the outcome and molecular characterization of A. baumannii. Doxycycline minimal inhibitory concentrations were evaluated by the broth dilution method. One hundred patients were included with a median age of 51 years. The leading site of infection was pulmonary (n = 62), followed by the soft tissues and skin (n = 28). A. baumannii resistant to carbapenem was found on 94%. The gene blaOXA-23 and blaOXA-51 were amplified in all recovered isolates of A. baumannii (n = 44). Doxycycline MIC50 and MIC90 were 1 µg/mL and 2 µg/mL, respectively. Death rate at 14 days and 28 days of follow-up was 9% and 14%, respectively. The prognostic factors related to death at end of follow-up were age > 49 years [85.7% vs. 46%, CI 95% 6.9 (1.4-32.6), P = 0.015] and hemodialysis [28.6% vs. 7%, CI 95% 5.33 (1.2-22.1), P = 0.021]. Patients treated with doxycycline to A. baumannii presented a relatively low death rate, and risk factors related to death were age and hemodialysis. Further and larger studies should compare polymyxin to doxycycline to better understand the differences between these therapeutic options.
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Infecções por Acinetobacter , Acinetobacter baumannii , Humanos , Pessoa de Meia-Idade , Doxiciclina/farmacologia , Doxiciclina/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Polimixinas/uso terapêutico , Estudos Retrospectivos , Carbapenêmicos/farmacologia , Carbapenêmicos/uso terapêutico , Testes de Sensibilidade Microbiana , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , beta-Lactamases/genéticaRESUMO
The acquisition of bla OXA genes encoding different carbapenem-hydrolyzing class-D ß-lactamases (CHDL) represents a main determinant of carbapenem resistance in the nosocomial pathogen Acinetobacter baumannii. The blaOXA-58 gene, in particular, is generally embedded in similar resistance modules (RM) carried by plasmids unique to the Acinetobacter genus lacking self-transferability. The ample variations in the immediate genomic contexts in which blaOXA-58 -containing RMs are inserted among these plasmids, and the almost invariable presence at their borders of non-identical 28-bp sequences potentially recognized by the host XerC and XerD tyrosine recombinases (pXerC/D-like sites), suggested an involvement of these sites in the lateral mobilization of the gene structures they encircle. However, whether and how these pXerC/D sites participate in this process is only beginning to be understood. Here, we used a series of experimental approaches to analyze the contribution of pXerC/D-mediated site-specific recombination to the generation of structural diversity between resistance plasmids carrying pXerC/D-bounded bla OXA-58- and TnaphA6-containing RM harbored by two phylogenetically- and epidemiologically-closely related A. baumannii strains of our collection, Ab242 and Ab825, during adaptation to the hospital environment. Our analysis disclosed the existence of different bona fide pairs of recombinationally-active pXerC/D sites in these plasmids, some mediating reversible intramolecular inversions and others reversible plasmid fusions/resolutions. All of the identified recombinationally-active pairs shared identical GGTGTA sequences at the cr spacer separating the XerC- and XerD-binding regions. The fusion of two Ab825 plasmids mediated by a pair of recombinationally-active pXerC/D sites displaying sequence differences at the cr spacer could be inferred on the basis of sequence comparison analysis, but no evidence of reversibility could be obtained in this case. The reversible plasmid genome rearrangements mediated by recombinationally-active pairs of pXerC/D sites reported here probably represents an ancient mechanism of generating structural diversity in the Acinetobacter plasmid pool. This recursive process could facilitate a rapid adaptation of an eventual bacterial host to changing environments, and has certainly contributed to the evolution of Acinetobacter plasmids and the capture and dissemination of bla OXA-58 genes among Acinetobacter and non-Acinetobacter populations co-residing in the hospital niche.
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Objectives: Our study aimed to elucidate the clonal diversity of carbapenem-resistant Acinetobacter clinical isolates producing NDM-type carbapenemase collected through national surveillance in Cuba during a 7-year period (2013-19). Methods: A total of 199 isolates of Acinetobacter spp. from 37 hospitals in 12 provinces were genetically analyzed for their species, carbapenemase genes and genotypes. Sequence type (ST) and OXA-51-like gene type were determined for bla NDM-positive isolates. Results: Most isolates (95%) were identified as species of Acinetobacter calcoaceticus-baumannii complex, with A. baumannii being the majority. Acquired carbapenemase genes were assigned to bla OXA or bla NDM type; the most commonly detected gene was bla OXA-23-like (49%), followed by bla OXA-24-like (20%) and bla NDM (15%). Twenty-nine bla NDM-positive isolates (22 A. baumannii, 2 A. pittii, 2 A. johnsonii, 3 other species) were differentiated into 19 STs, including the most common, ST23. Though NDM genes were mostly typed as bla NDM-1, a novel bla NDM-42 was identified in an ST79 A. baumannii isolate. bla OXA-51-like genes of NDM-positive A. baumannii were discriminated into 10 OXA types, including 2 novel ones. Conclusions: Our study indicated the spread of bla NDM to various clones of A. baumannii and other Acinetobacter spp. in Cuba.
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INTRODUCCIÓN: La aparición y diseminación de Enterobacterales resistentes a carbapenémicos ha generado un gran impacto en las infecciones asociadas a la atención de salud en el mundo. Recientemente, en Chile se detectó un brote por Klebsiella pneumoniae productora de carbapenemasas tipo oxacilinasas (OXA) de la subfamilia tipo OXA-48, reportándose los primeros casos en pacientes hospitalizados mayoritariamente en la zona norte del país. OBJETIVO: Determinar los perfiles fenotípicos, genotípicos y de susceptibilidad antimicrobiana de 16 cepas referidas durante mayo del año 2021 desde las regiones de Antofagasta y Metropolitana al Laboratorio de Referencia del Instituto de Salud Pública. METODOLOGÍA: Las cepas provenientes de muestras clínicas fueron analizadas mediante técnicas tradicionales (Kirby-Bauer y epsilometría) y automatizadas, además de técnicas colorimétricas, inmunocromatográficas y moleculares (RPC y PFGE). Resultados: Se detectó la presencia de los genes blaoxa-48 y blaoxa-232 con una resistencia inusual, tanto a carbapenémicos (ertapenem, imipenem y meropenem) como a cefalosporinas (cefepime, cefotaxima y ceftazidima), además de piperacilina/tazobactam y temocilina. Se detectaron dos subtipos por PFGE, siendo predominante el clon CL-Kpn-Spe-329 (93,8%) con dos mecanismos de resistencia identificados: carbapenemasa y β-lactamasa de espectro extendido (BLEE). CONCLUSIÓN: Ante esta alerta epidemiológica es necesario unificar criterios existentes en la red asistencial nacional para la oportuna detección, vigilancia y control de posibles brotes de cepas productores de oxacilinasa tipo OXA-48.
BACKGROUND: The appearance and spread of carbapenems-resistant Enterobacterales have generated a major impact on health care-associated infections worldwide. Recently, a Klebsiella pneumoniae outbreak expressing OXA-48 like-carbapenemases was detected in Chile, the first reported cases corresponded to hospitalized patients mainly from northern Chile. AIM: To characterize the phenotypic and genotypic profiles of antimicrobial susceptibility of 16 clinical isolates referred during May 2021 from Antofagasta and Metropolitan regions to the Reference Laboratory of Instituto de Salud Publica. METHODS: Antimicrobial susceptibility of all strains was analyzed using traditional (Kirby-Bauer and epsilometry) and automated methods, and complemented with colorimetric, immunochromatographic and molecular (PCR and PFGE) techniques. RESULTS: As a result of the genetic characterization, blaoxa-48 and blaoxa-232 genes were detected, showing the isolates an unusual resistance profile to both carbapenems (ertapenem, imipenem, and meropenem) and cephalosporins (cefepime, cefotaxime, and ceftazidine), as well as piperacillin/ tazobactam and temocillin. Two subtypes were detected by PFGE, with a predominant clone CL-Kpn-Spe-329 (93.8%), with two resistance mechanisms identified: carbapenemase and extended-spectrum β-lactamase (ESBL). CONCLUSION: Due to this epidemiological alert, it is essential the establishment of national guidelines for early detection, surveillance, and control of future outbreaks of OXA-48 like carbapenemases isolates.
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Humanos , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/genética , Fenótipo , beta-Lactamases , Testes de Sensibilidade Microbiana , Chile , Genótipo , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Antibacterianos/farmacologiaRESUMO
OBJECTIVES: The emergence and spread of carbapenem resistant clones is of major concern for global health. This study aimed to characterize the first detected Klebsiella pneumoniae ST15 harboring the epidemic carbapenemase OXA-48 in South America. METHODS: During a routine colonization screening with carbapenem-resistant bacteria, one K. pneumoniae strain (CGHM01) was isolated from the urine of a hospitalized patient suffering from a neurodegenerative disease in Uruguay. We used long-read whole-genome sequencing and a phylogenomic approach to characterize the emergence of K. pneumoniae CGHM01. RESULTS: K. pneumoniae CGHM01 is a multi-drug resistant strain carrying an IncL/M plasmid that encodes the carbapenemase gene blaOXA-48 within the Tn1999.2 transposon. Also, it carries an IncR plasmid harboring a class I integron with an array of antibiotic resistance genes including the extended-spectrum beta-lactamase blaCTX-M-15. Two copies of blaCTX-M-15 were also inserted in different positions of the chromosome. CGHM01 belongs to a ST15 sublineage that likely originated in continental Spain around 2012. CONCLUSIONS: The asymptomatic carriage of this strain in the urinary tract warns of difficulties for detection and reporting of emerging carbapenem-resistant clones in new geographic areas where these are not endemic.
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Infecções por Klebsiella , Doenças Neurodegenerativas , Carbapenêmicos , Humanos , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana , beta-Lactamases/genéticaRESUMO
Diazabicyclooctanone inhibitors such as ETX2514 and avibactam have shown enhanced inhibitory performance to fight the antibiotic resistance developed by pathogens. However, avibactam is ineffective against Acinetobacter baumannii infections, unlike ETX2514. The molecular basis for this difference has not been tackled from a molecular approach, precluding the knowledge of relevant information. In this article, the mechanisms involved in the inhibition of OXA-24 by ETX2514 and avibactam are studied theoretically by hybrid QM/MM calculations. The results show that both inhibitors share the same inhibition mechanisms, comprising acylation a deacylation stages. The involved mechanisms include the same number of steps, transition states and intermediates; although they differ in the involved activation barriers. This difference accounts for the dissimilar inhibitory ability of both inhibitors. The molecular reason for this is the endocyclic double bond in the piperidine ring of ETX2514 increasing the ring strain and chemical reactivity on the N6 and C7 atoms, besides the methyl substituent, which enhance the hydrophobic character of the ring. Furthermore, Lys218 and the carboxylated Lys84 of ETX2514, play a crucial role in the mechanism by coordinating their protonation states in an on/off (protonated/deprotonated) manner, favoring the proton transference between the residues and the inhibitor.
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Antibacterianos , Inibidores de beta-Lactamases , Antibacterianos/química , Antibacterianos/farmacologia , Compostos Azabicíclicos , Testes de Sensibilidade Microbiana , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/químicaRESUMO
This is the first detection and genomic analysis of an OXA-181-carbapenemase-producing E. coli in Brazil, from a traveler returning from Sub-Saharan Africa. The ST167 isolate carries blaOXA-181 inserted in an IncX3 plasmid. This report illustrates the potential role of travelers as silent vectors for dissemination of high-risk resistant clones.
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Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Proteínas de Escherichia coli/genética , Escherichia coli/genética , beta-Lactamases/genética , Adulto , África Subsaariana , Brasil/epidemiologia , Fezes/microbiologia , Genoma Bacteriano , Humanos , Masculino , Testes de Sensibilidade Microbiana , PlasmídeosRESUMO
INTRODUCTION: Proteus mirabilis is one of the main pathogens that cause urinary tract infections. Therefore, the aim of this study was to analyze and compare the genetic profile of 36 clinical isolates of P. mirabilis that carry and do not carry the blaKPC and blaNDM gene with respect to virulence factors (mrpG, pmfA, ucaA, nrpG and pbtA) and antimicrobial resistance (blaVIM,blaIMP, blaSPM, blaGES,blaOXA-23-like, blaOXA-48-like, blaOXA-58-like and blaOXA-10-like). METHODS: The virulence and resistance genes were investigated by using PCR and sequencing. RESULTS: ERIC-PCR typing showed that the isolates showed multiclonal dissemination and high genetic variability. The gene that was most found blaOXA-10-like (n = 18), followed by blaKPC (n = 10) and blaNDM (n = 8). To our knowledge, this is the first report of blaOXA-10 in P. mirabilis in Brazil, as well as the first report of the occurrence of P. mirabilis co-carrying blaOXA-10/blaKPC and blaOXA-10/blaNDM. The blaNDM or blaKPC carrier isolates showed important virulence genes, such as ucaA (n = 8/44.4%), pbtA (n = 10/55.5%) and nrpG (n = 2/11.1%). However, in general, the non-carrier isolates of blaKPC and blaNDM showed a greater number of virulence genes when compared to the carrier group. CONCLUSION: Clinical isolates of P. mirabilis, in addition to being multi-drug resistant, presented efficient virulence factors that can establish infection outside the gastrointestinal tract.
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Proteus mirabilis , Fatores de Virulência , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Brasil , Humanos , Testes de Sensibilidade Microbiana , Proteus mirabilis/genética , Fatores de Virulência/genética , beta-Lactamases/genéticaRESUMO
The orexin peptides promote hedonic intake and other reward behaviors through different brain sites. The opioid dynorphin peptides are co-released with orexin peptides but block their effects on reward in the ventral tegmental area (VTA). We previously showed that in the paraventricular hypothalamic nucleus (PVN), dynorphin and not orexin peptides enhance hedonic intake, suggesting they have brain-site-specific effects. Obesity alters the expression of orexin and dynorphin receptors, but whether their expression across different brain sites is important to hedonic intake is unclear. We hypothesized that hedonic intake is regulated by orexin and dynorphin peptides in PVN and that hedonic intake in obesity correlates with expression of their receptors. Here we show that in mice, injection of DYN-A1-13 (an opioid dynorphin peptide) in the PVN enhanced hedonic intake, whereas in the VTA, injection of OXA (orexin-A, an orexin peptide) enhanced hedonic intake. In PVN, OXA blunted the increase in hedonic intake caused by DYN-A1-13. In PVN, injection of norBNI (opioid receptor antagonist) reduced hedonic intake but a subsequent OXA injection failed to increase hedonic intake, suggesting that OXA activity in PVN is not influenced by endogenous opioid activity. In the PVN, DYN-A1-13 increased the intake of the less-preferred food in a two-food choice task. In obese mice fed a cafeteria diet, orexin 1 receptor mRNA across brain sites involved in hedonic intake correlated with fat preference but not caloric intake. Together, these data support that orexin and dynorphin peptides regulate hedonic intake in an opposing manner with brain-site-specific effects.
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Dinorfinas , Núcleo Hipotalâmico Paraventricular , Analgésicos Opioides/metabolismo , Analgésicos Opioides/farmacologia , Animais , Encéfalo/metabolismo , Dinorfinas/metabolismo , Dinorfinas/farmacologia , Camundongos , Obesidade/metabolismo , Orexinas/metabolismoRESUMO
RESUMEN Las carbapenemasas se encuentran ampliamente distribuidas en nuestro país, tanto en bacilos gramnegativos fermentadores como no fermentadores. Durante 2021, se ha reportado incremento de cepas con estas enzimas. Con el objetivo de evaluar la doble producción de carbapenemasas en Enterobacterales y comunicar su circulación, fue puesta a punto una PCR convencional múltiple. Estudio retrospectivo en 128 aislamientos provenientes de 20 centros colaboradores de la Red Nacional de Vigilancia de la RAM (Capital, Central e interior del país), remitidos al LCSP entre febrero y setiembre de 2021, para confirmación y genotipificación de carbapenemasas. Se realizaron pruebas fenotípicas y colorimétricas con sustratos específicos, y pruebas genotípicas (PCR convencional múltiple) para la detección simultánea de varios genes de resistencia (bla NDM, bla KPC, bla OXA-48-like, bla IMP y bla VIM). De los 128 aislamientos estudiados, 107 correspondieron a Klebsiella pneumoniae, 14 a Enterobacter cloacae complex, entre otros; aislados en mayor frecuencia de muestras de orina (30%), respiratorias (30%), sangre y catéter (24%). Los genes de resistencia a los carbapenemes detectados fueron: bla NDM (77,3%), bla KPC (17,2%); siendo confirmada la doble producción de carbapenemasas en 7 aislamientos (5,5%) provenientes de 4 centros diferentes de la capital de país y uno de Central; 6 de ellas (K. pneumoniae) con bla NDM+bla KPC y 1 (E. cloacae complex) con bla NDM+bla OXA-48-like; confirmando circulación de Enterobacterales dobles productores de carbapenemasas en el país (KPC+NDM y OXA+NDM); hallazgos que obligan a proveer de capacidades de detección, de manera a que se puedan tomar medidas oportunas y eficaces de contención y control.
ABSTRACT Carbapenemases are widely distributed in our country, both in fermenting and non-fermenting gram-negative bacilli. During 2021, an increase in strains with these enzymes has been reported. In order to evaluate the double production of carbapenemases in Enterobacterales and communicate their circulation, a multiple conventional PCR was set up. Retrospective study carried out in 128 isolates from 20 collaborating centers of the National AMR Surveillance Network (Capital, Central and interior of the country), sent to the LCSP between February and September 2021, for confirmation and genotyping of carbapenemases. Phenotypic and colorimetric tests were performed with specific substrates, as well as genotypic tests (multiple conventional PCR) for the simultaneous detection of several resistance genes (blaNDM, blaKPC, blaOXA-48-like, blaIMP and blaVIM). Of the 128 isolates studied, 107 corresponded to Klebsiella pneumoniae, 14 to Enterobacter cloacae complex, among others; isolated in higher frequency from urine (30%), respiratory (30%), blood and catheter (24%) samples. The genes for resistance to carbapenems detected were: blaNDM (77.3%), blaKPC (17.2%); the double production of carbapenemases was confirmed in 7 isolates (5.5%) from 4 different centers in the capital of the country and one in Central; 6 of them (K. pneumoniae) with blaNDM + blaKPC and 1 (E. cloacae complex) with blaNDM + blaOXA-48-like; confirming circulation of double Enterobacterales producers of carbapenemases in the country (KPC + NDM and OXA + NDM); findings that require the provision of detection capabilities, so that timely and effective containment and control measures can be taken.
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Background: Carbapenemase-producing Enterobacteriaceae(CPE) represents a global public health concern and systemic infectionsassociatedwithOXA-48 carbapenemase are increasingly being reported in Latin America. Here, we present the first 2 cases of systemic infections by OXA-48-ProducingKlebsiellapneumoniaein Peru. A favorable clinical response was observed after targeted treatment with colistin as a backbone.
Introducción: Las enterobacterias productoras de carbapenemasas (EPC) representan un problema de salud pública y cada vez hay más reportes de infecciones sistémicas asociadas con la carbapenemasa OXA-48 en America Latina. Presentamos los primeros 2 casos de infecciones sistémicas por Klebsiella pneumoniae productora de OXA-48 en Perú. Se observó una respuesta clínica favorable luego del tratamiento dirigido con colistina como base.
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Abstract INTRODUCTION: In this study, we report a clonal dissemination of carbapenem resistant Acinetobacter baumannii isolates due to the acquisition of blaOXA-23 in a regional hospital located in Brazilian Amazon Region. METHODS: The isolates were identified by MALDI-TOF and the carbapenemase-encoding genes were detected by multiplex-PCR. The genetic similarity was investigated by pulsed-field gel electrophoresis (PFGE). RESULTS: Only 10 (55.6%) isolates harbored the gene bla OXA-23. PFGE analysis revealed that these isolates belong to a single clone. CONCLUSIONS: This dissemination strategy indicates the need for surveillance, adoption of control procedures defined in guidelines, and the careful administration of antimicrobials should be reinforced.
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Humanos , Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/genética , Proteínas de Bactérias/genética , beta-Lactamases/genética , Brasil/epidemiologia , Resistência a Medicamentos , Testes de Sensibilidade Microbiana , Eletroforese em Gel de Campo Pulsado , Epidemiologia Molecular , Hospitais , Antibacterianos/farmacologiaRESUMO
Novel variants of OXA-48-type enzymes with the ability to hydrolyze oxyimino-cephalosporins and carbapenems are increasingly reported. Since its first report in 2011, OXA-163 is now extensively spread throughout Argentina, and several variants like OXA-247 have emerged. Here, we characterized a new blaOXA-48-like variant, OXA-438, and we performed a comparative kinetic analysis with the local variants OXA-247 and OXA-163 and the internationally disseminated OXA-48. blaOXA-163, blaOXA-247, and blaOXA-438 were located in a 70 kb IncN2 conjugative plasmid. OXA-438 presented mutations in the vicinity of conserved KTG (214-216), with a 2-aa deletion (R220-I221) and a D224E shift (as in OXA-163) compared to OXA-48. Despite Kpn163 (OXA-163), Kpn247 (OXA-247) and Eco438 (OXA-438) were resistant to meropenem and ertapenem, and the transconjugants (TC) remained susceptible (however, the carbapenems minimum inhibitory concentrations were ≥3 times 2-fold dilutions higher than the acceptor strain). TC163 and Eco48 were resistant to oxyimino-cephalosporins, unlike TC247 and TC438. kcat/Km values for cefotaxime in OXA-163 were slightly higher than the rest of the variants that were accompanied by a lower Km for carbapenems. For OXA-163, OXA-247, and OXA-438, the addition of NaHCO3 improved kcat values for both cefotaxime and ceftazidime; carbapenems kcat/Km values were higher than for oxyimino-cephalosporins. Mutations occurring near the conserved KTG in OXA-247 and OXA-438 are probably responsible for the improved carbapenems hydrolysis and decreased inactivation of oxyimino-cephalosporins compared to OXA-163. Dichroism results suggest that deletions at the ß5-ß6 loop seem to impact the structural stability of OXA-48 variants. Finally, additional mechanisms are probably involved in the resistance pattern observed in the clinical isolates.
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Carbapenêmicos , beta-Lactamases , Carbapenêmicos/farmacologia , Cefalosporinas , Cinética , Testes de Sensibilidade Microbiana , beta-Lactamases/genética , beta-Lactamases/metabolismoRESUMO
OBJECTIVE: Carbapenemase-producing Acinetobacter baumannii has been recognized as a critical priority pathogen by the World Health Organization. We hereby report the identification and the draft genome sequence of a carbapenem-resistant A. baumannii isolated from a patient with community-onset urinary tract infection, in a Chilean Patagonian city. METHODS: The whole genome was sequenced on an Illumina NextSeq platform and de novo assembled using Unicycler v.0.4. Resistome analysis and epidemiological investigation (based on MLST data and Pasteur scheme) were performed using bioinformatics tools available from the Center for Genomic Epidemiology. RESULTS: The genome size was calculated at 3890824 bp, with a GC content of 39.1%, comprising 3864 total genes, 30 tRNAs, 3 rRNAs, 4 ncRNAs, and 109 pseudogenes. Carbapenem-resistant A. baumannii Ab3_Ch strain belonged to the international sequence type ST15 (clonal complex, CC15), and harboured the ISAba-1-blaOXA-219 gene array, along to blaTEM-1B and blaADC-6 ß-lactamase genes, and aac(3)-IIa and aph(3')-VIa aminoglycoside resistance genes. Additionally, efflux pump encoding genes (abaF, abaQ, abeS, adeI, adeK, adeL, adeN, adeR, adeS, and amvA) were identified, and mutations in the quinolone resistance-determining region of gyrA (Ser81Leu) and parC (Ser84Leu) were considered responsible for fluoroquinolone resistance. CONCLUSION: This genome sequence data could be used for comparative genomic studies of critical priority A. baumannii strains, as well as to understand the specific features of hospital-associated A. baumannii lineages of international clonal complexes emerging in community settings.