Salmonella Heidelberg and Salmonella Minnesota in Brazilian broilers: Genomic characterization of third-generation cephalosporin and fluoroquinolone-resistant strains

Salmonella serovars Heidelberg and Minnesota encoding antimicrobial resistance to third-generation cephalosporins and fluoroquinolones are often detected in poultry/poultry meat. We analysed the genomes of 10 Salmonella Heidelberg (SH) and 4 Salmonella Minnesota (SM) from faecal isolates of Brazilian poultry. These featured virulent and multidrug-resistant characteristics, with AmpC beta-lactamase (blaCMY-2 ) predominance (9/14), for all SM (4/4) and some SH (3/10) located on IncC plasmid replicons. IncC carrying blaCTX-M-2 was only detected among SH (3/10). Mutation in the gyrA/parC genes was present in all SH, whereas SM harboured parC mutation plus qnrB19 on ColRNAI plasmids (3/4). In silico resistance overall corroborated with phenotypic results. Core genome phylogenies showed close clustering and high similarities between the Brazilian and poultry meat/food isolates from Europe, and to human isolates from European countries with documented import of Brazilian poultry meat. Conjugation assays with SM successfully transferred blaCMY-2 , and qnrB19 to an Escherichia coli recipient. The findings reinforce the ongoing antimicrobial resistance acquisition of SH and Minnesota and the risks for disseminating resistant strains and/or mobile elements which may increasingly affect importing countries and the need for controlling AMR in major poultry-exporting countries like Brazil.

MDR Escherichia coli carrying CTX-M-24 (IncF[F-:A1:B32]) and KPC-2 (IncX3/IncU) plasmids isolated from community-acquired urinary trainfection in Brazil

ABSTRACT Acquired antibiotic resistance in bacteria has become an important worldwide challenge. Currently, several bacteria, including Escherichia coli, have multidrug resistance profiles. Genes such as bla CTX-M-24 and bla KPC-2 (carbapenemase) are widespread. This research letter reports about a genomic surveillance study where multidrug-resistant E. coli containing CTX-M-24(IncF [F-:A1:B32]) and KPC-2(IncX3/IncU) plasmids were obtained from community- acquired urinary tract infection in Brazil.

Production of Medical Grade Silicone for Facial Prosthesis with Bactericidal Properties from the Inclusion of Poly (Diallyldimethylammonium Chloride): An in Vitro Study

Objective: To evaluate the inclusion capacity and bactericidal efficiency of diallyl dimethyl ammonium chloride (PDADMAC) diluted in tetrahydrofuran (THF) upon inclusion in the medical grade silicone polymer structure. Material and Methods: It was diluted the PDADMAC in THF at the concentration of 4wt%. It was included in the silicon paste during its vulcanization process. The contact angle measurements were performed to evaluate whether the biocide inclusion into the silicon paste was successful. All samples were sterilized with gamma radiation at 25KGy-dosage prior to the microbiological tests. Microbiological testing strictly followed the Antibacterial products - Test for antibacterial activity and efficacy JIS Z 2801: 201010 and the used of specific bacteria, as Staphylococcus aureus ATCC 6538P and Escherichia coli ATCC 8739. Results: The results showed that PDADMAC, when dissolved in THF at 4wt%, displayed good incorporation in medical silicone and a broad-spectrum antibacterial response. The results of the tests using Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538P showed that the silicone with no biocide addition did not present antibacterial activity. In contrast, the experimental group plus 2 mL of PDADMAC would have an ideal antibacterial response. Conclusion: Medical grade silicone can be used as a material with antibacterial properties, since it has been able to keep PDADMAC compound attached to its structure, thus acquiring antimicrobial property.

Clinical and microbiological characteristics of OXA-23- and OXA-143-producing Acinetobacter baumannii in ICU patients at a teaching hospital, Brazil

ABSTRACT Background: Carbapenem-resistant Acinetobacter baumannii (CRAb) is an important cause of nosocomial infections especially in intensive care units. This study aimed to assess clinical aspects and the genetic background of CRAb among ICU patients at a Brazilian teaching hospital. Methods: 56 critically ill patients colonized or infected by CRAb, during ICU stay, were prospectively assessed. Based on imipenem MIC ≥ 4 µg/mL, 28 CRAB strains were screened for the presence of genes encoding metallo-β-lactamases and OXA-type β-lactamases. The blaOXA-type genes were characterized by PCR using primers targeting ISAba-1 or -3. Genetic diversity of blaOXA-positive strains was determined by ERIC-PCR analysis. Results: Patient's mean age (±SD) was 61 (±15.1), and 58.9% were male. Eighty-percent of the patients presented risk factors for CRAb colonization, mainly invasive devices (87.5%) and previous antibiotic therapy (77.6%). Thirty-three patients died during hospital stay (59.0%). Resistance to carbapenems was associated with a high prevalence of blaOXA-23 (51.2%) and/or blaOXA-143 (18.6%) genes. ERIC-PCR genotyping identified 10 clusters among OXA-producing CRAb. Three CRAb strains exhibited additional resistance to polymyxin B (MIC ≥ 4 µg/mL), whereas 10 CRAb strains showed tigecycline MICs > 2 µg/mL. Conclusions: In this study, clonally unrelated OXA-123- and OXA-143-producing A. baumannii strains in ICU patients were strongly correlated to colonization with infected patients being associated with a poor outcome.

Epidemiologia das betalactamases de espectro estendido no Brasil: impacto clínico e implicações para o agronegócio / Epidemiology of extended-spectrum beta-lactamases in Brazil: clinical impact and implications for agribusiness

A emergência e a disseminação de bactérias produtoras de betalactamases de espectro estendido (ESBL) têm sido retratadas como grande problema de saúde pública, especialmente no que diz respeito a patógenos associados às infecções relacionadas com a assistência à saúde (IRAS). No Brasil, a maior preocupação inclui as altas taxas de resistência a Klebsiella pneumoniae e Escherichia coli, embora as ESBL estejam amplamente disseminadas entre os membros da família Enterobacteriaceae e sejam descritas como enzimas do tipo TEM, SHV, CTX-M, VEB, BES e GES em diferentes estados. Contudo, as enzimas dos grupos CTX-M-2, CTX-M-8 e CTX-M-9 são as mais prevalentes em território brasileiro. Além do ambiente hospitalar, as ESBL de origem comunitária e ambiental têm sido retratadas. A CTX-M-2 também tem sido identificada em Salmonella, oriunda do ciclo de produção animal, o que é alarmante para o Brasil diante da importância que a exportação de carnes assume para o agronegócio. Dessa forma, faz-se necessária a regulamentação do uso de antimicrobianos em todos os setores, a fim de evitar a disseminação de bactérias resistentes e resguardar a qualidade e a inocuidade dos alimentos. Portanto, o presente estudo visa retratar o panorama geral da epidemiologia das ESBL no Brasil, enfatizando o impacto clínico, ambiental e econômico.

The emergence and dissemination of extended-spectrum beta-lactamase bacteria (ESBL) have been reported as a major public health issue, mainly with regard to nosocomial infections. In Brazil, ESBL are widely disseminated among the Enterobacteriaceae family and enzymes TEM, SHV, CTX-M, VEB, BES and GES have been reported in several states. However, the major concern is the high rates of resistant Klebsiella pneumoniae and Escherichia coli strains. Currently, ESBL belonging to CTX-M-2, CTX-M-8 and CTX-M-9 subtypes are the most prevalent in Brazil. Apart from nosocomial infections, ESBL bacteria from outpatient and environmental samples have been identified. CTX-M-2 has been identified in Salmonella samples from animal production, which may have dire consequences for agribusiness, particularly meat export in Brazil. Thus, the regulation of antimicrobial agents is vital in order to avoid the dissemination of multidrug-resistant bacteria and to assure the quality and innocuousness of food products. Therefore, this review aims to report the epidemiology of ESBL in Brazil, focusing on their clinical, environmental and economic impact.

Pseudomonas aeruginosa multirresistente: um problema endêmico no Brasil / Multidrug-resistant Pseudomonas aeruginosa: an endemic problem in Brazil

Relatos mundiais têm documentado a problemática da endemicidade de isolados clínicos de Pseudomonas aeruginosa multirresistente (MDR) aliada a elevados índices de morbidade/mortalidade. No Brasil, surtos de infecção ocasionados por P. aeruginosa têm sido relacionados com uma disseminação clonal da espécie. Atualmente, as opções terapêuticas para o tratamento das infecções causadas por esse microrganismo são limitadas, muitas vezes restringindo-se ao uso de carbapenêmicos (p. ex., imipenem [IPM]). Assim, a resistência ao IPM é uma questão de saúde pública, uma vez que esse antibiótico é empregado como último recurso no tratamento de infecções de origem hospitalar, causadas por bactérias Gram-negativas multirresistentes. No Brasil, os principais mecanismos relacionados com fenótipos multirresistentes de P. aeruginosa são produção de metalobetalactamase (MBL) do tipo SPM-1, presença de metilase 16S rRNA RmtD, perda de porina OprD e superexpressão de bombas de efluxo, o que pode explicar os altos índices de resistência a carbapenêmicos e aminoglicosídeos. A emergência de cepas com essas características é preocupante, tendo em vista a escassez de terapias efetivas no tratamento de infecções por esse patógeno. Finalmente, com base em relatos nacionais, publicados por diferentes grupos de pesquisa, podemos deduzir que a convergência de múltiplos mecanismos de resistência em P. aeruginosa tem sido um evento favorável para a seleção de diferentes clones endêmicos multirresistentes disseminados no Brasil.

Global reports have documented the endemicity of multidrug-resistant (MDR) Pseudomonas aeruginosa associated with high levels of morbidity/mortality. In Brazil, outbreaks of MDR P. aeruginosa have been related to clonal dissemination. Currently, therapeutic options for the treatment of these infections are restricted to carbapenemic antibiotics (i.e., imipenem [IPM]). Thus, carbapenem resistance is a public health issue, since carbapenems are considered the last resort to nosocomial infections caused by MDR Gram-negative bacteria. In Brazil, the main mechanisms associated with MDR P. aeruginosa phenotypes are metallo-betalactamase (MBL) production (SPM-1 enzyme), presence of 16S rRNA methylase RmtD, loss of OprD porin, and overexpression of efflux pumps, which may explain the high level of carbapenem and aminoglycoside resistance. Accordingly, the emergence and dissemination of MDR strains is worrisome. Finally, based on national reports published by different groups of investigators, it is deduced that the convergence of multiple mechanisms of P. aeruginosa resistance has played a major role in the selection of endemic MDR clones widespread in Brazil.

Characterization of class 1 integrons and antibiotic resistance genes in multidrug-resistant Salmonella enterica isolates from foodstuff and related sources

In recent years, an increase in the occurrence of antimicrobial resistance among Salmonella enterica has been observed in several countries, which is worrisome because S. enterica is one of the most common causes of human gastroenteritis worldwide. The aim of this study was to characterize class 1 integrons and antibiotic resistance genotypes in Salmonella enterica isolates recovered from foodstuff and related sources. Nineteen multidrug-resistant (MDR) Salmonella enterica isolates were recovered. Higher resistance rates to tetracycline (90 percent), streptomycin (80 percent), sulfamethoxazole-trimethoprim (80 percent), ampicillin (60 percent) and nalidixic acid (70 percent) were related to the presence of the tetA, aadA, sul1/sul2, blaTEM-1 genes, and a codon mutation at position 83 of the gyrA gene, respectively. Class 1 integrons harboring aadA, blaTEM-1, sul1 or dhfr1 genes were detected in nine (45 percent) Salmonella enterica strains belonging to serotypes Brandenburg, Panama, Agona, Mbandaka and Alachua. Finally, clonal dissemination of S. Panama, S. Derby and S. Mbandaka was confirmed by PFGE. Detection of clonally related MDR Salmonella enterica suggests that endemic serotypes can be supported by class 1 integron-borne gene cassettes and/or mutations in drug targets. Emergence and dissemination of multidrug-resistant Salmonella enterica can have a major public health impact in an environment where large-scale suppliers ship their products.

Presence of blaTEM-116 gene in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei from Brazil

It is known that Aeromonas spp. possess different chromosomal â-lactamase genes. Presence and phenotypic expression of blaTEM, blaSHV, and blaCTX-M ESBL-encoding genes were investigated in environmental water isolates of Aeromonas hydrophila and Aeromonas jandaei. Presence of blaSHV and blaCTX-M genes was not observed, and blaTEM gene was verified in 91 percent of the isolates. Sequencing of 10 fragments showed the occurrence of blaTEM-116.

Extended-spectrum beta-lactamases among Enterobacteriaceae isolated in a public hospital in Brazil / Beta-lactamases de espectro estendido em Enterobacteriaceae isoladas de Hospital Público no Brasil

Extended-spectrum β-lactamases (ESBL) in enterobacteria are recognized worldwide as a great hospital problem. In this study, 127 ESBL-producing Enterobacteriaceae isolated in one year from inpatients and outpatients at a public teaching hospital at São Paulo, Brazil, were submitted to analysis by PCR with specific primers for blaSHV, blaTEM and blaCTX-M genes. From the 127 isolates, 96 (75.6 percent) Klebsiella pneumoniae, 12 (9.3 percent) Escherichia coli, 8 (6.2 percent) Morganella morganii, 3 (2.3 percent) Proteus mirabilis, 2 (1.6 percent) Klebsiella oxytoca, 2 (1.6 percent) Providencia rettgeri, 2 (1.6 percent) Providencia stuartti, 1 (0.8 percent) Enterobacter aerogenes and 1 (0.8 percent) Enterobacter cloacae were identified as ESBL producers. BlaSHV, blaTEM and blaCTX-M were detected in 63 percent, 17.3 percent and 33.9 percent strains, respectively. Pulsed field gel eletrophoresis genotyping of K. pneumoniae revealed four main molecular patterns and 29 unrelated profiles. PCR results showed a high variety of ESBL groups among strains, in nine different species. The results suggest the spread of resistance genes among genetically different strains of ESBL-producing K. pneumoniae in some hospital wards, and also that some strongly related strains were identified in different hospital wards, suggesting clonal spread in the institutional environment.

Beta-lactamases de espectro estendido (ESBL) em enterobactérias são reconhecidas mundialmente como um grande problema hospitalar. Neste estudo, 127 Enterobacteriaceae produtoras de ESBL isoladas por um ano, de pacientes internados e ambulatoriais de um hospital público de ensino em São Paulo, Brasil, foram submetidas à análise pela PCR com iniciadores específicos para os genes blaSHV, blaTEM e blaCTX-M. Dos 127 isolados, 96 (75,6 por cento) K. pneumoniae, 12 (9,3 por cento) E. coli, 8 (6,2 por cento) M. morganii, 3 (2,3 por cento) Proteus mirabilis, 2 (1,6 por cento) Klebsiella oxytoca, 2 (1,6 por cento) Providencia rettgeri, 2 (1,6 por cento) Providencia stuartti, 1 (0,8 por cento) Enterobacter aerogenes e 1 (0,8 por cento) Enterobacter cloacae foram identificados como produtores de ESBL. BlaSHV, blaTEM e blaCTX-M foram detectados em 63 por cento, 17,3 por cento e 33,9 por cento das cepas, respectivamente. A genotipagem de K. pneumoniae por eletroforese em campo pulsado revelou quatro padrões moleculares principais e 29 perfis não relacionados. Os resultados da PCR demonstraram alta variedade de grupos de ESBL entre as cepas, em nove espécies diferentes. Os resultados sugerem a disseminação de genes de resistência entre cepas geneticamente diferentes de K. pneumoniae produtoras de ESBL em algumas unidades do hospital, e também que algumas cepas fortemente relacionadas foram identificadas em unidades hospitalares diferentes, sugerindo disseminação clonal no ambiente da instituição.

DOD/AMB: in vivo activity of a novel amb formulation with synthetic cationic bilayer fragments

A habilidade do brometo de dioctadecildimetilamônio (DOBAB), em formar bicamada de lipídio sintético e a demonstração prévia do forte poder solubilizante de anfotericina B (ANB) , incentivou-nos a realizar a avaliação da atividade de DODAB/AMB in vivo contra candidíase sistêmica em modelo de camundongos para verificar a sua sobrevida bem como a recuperação das leveduras de C. albicans dos órgãos colonizados (baço e rins). O AMB foi simplesmente adicionado à DODAB em pó previamente disperso em água e sonicado com auxílio de ponteiras, nas concentrações de <0,1e 10 mg/mL, respectivamente, assegurando-se a completa ausência de solventes orgânicos nesta formulação. O estado de agregação do AMB foi avaliado por meio do espectro de absorção da luz UV-visível e a distribuição de tamanhos das formulações estudadas, determinadas por meio de analisador ZetaPlus Brookhaven Instruments Corporation, Holtsville, NY) equipado com um laser de 570 nm e dynamic light scattering (90ºC) para a medição dos tamanhos (Grabowski & Morrison, 1983). AMB foi estabilizada na bicamada de DODAB em forma monomérica, eliminando-se os grandes agregados de AMB insolúveis em água. Tanto a sobrevida dos animais como os experimentos com recuperação das leveduras dos órgãos colonizados (baço e rins) mostraram eficácia equivalente à demonstrada por Fungizona (DOC/AMB) - a sobrevida foi de 100 e 70% respectivamente nas concentrações de 0.4 mg/kg/dia via i.p. por 10 dias (P>0.05), em relação a eliminação da colonização de C. albicans dos rins e baço. Em resumo, DOD/AMB foi efetivo no tratamento de candidíase sistêmica em modelo animal.

DOD/AMB: in vivo activity of a novel amb formulation with synthetic cationic bilayer fragments

The ability of the versatile dioctadecyldimethylammonium bromide (DODAB), a bilayer-forming synthetic lipid previously shown to solubilize Amphotericin B (AMB), inspired this evaluation of in vivo activity of the DODAB/AMB formulation (DOD/AMB) against systemic candidiasis in a mouse model from survival and tissue burden experiments. AMB was simply added to a DODAB powder dispersion in water previously obtained by sonication with tip at concentrations 0.1 and 10 mg/mL, respectively, organic solvents completely absent. AMB aggregation state was evaluated from UV-visible light absorption and dynamic light scattering for aggregate sizing. AMB was stabilized by the DODAB bilayer fragments in its monomeric form, causing disappearance of large water insoluble drug aggregates. From survival and tissue burden experiments, DOD/AMB efficacy was equivalent to the one exhibited by Fungizone (DOC/AMB) - 100 and 70% survival respectively, at 0.4 mg/kg/day given i.p. for 10 days (P>0.05) -, regarding elimination of Candida colonization in spleen and kidneys. In summary, DOD/AMB, was effective for treating systemic candidiasis in a mouse model.

A habilidade do brometo de dioctadecildimetilamônio (DOBAB), em formar bicamada de lipídio sintético e a demonstração prévia do forte poder solubilizante de anfotericina B (ANB) , incentivou-nos a realizar a avaliação da atividade de DODAB/AMB in vivo contra candidíase sistêmica em modelo de camundongos para verificar a sua sobrevida bem como a recuperação das leveduras de C. albicans dos órgãos colonizados (baço e rins). O AMB foi simplesmente adicionado à DODAB em pó previamente disperso em água e sonicado com auxílio de ponteiras, nas concentrações de 0,1e 10 mg/mL, respectivamente, assegurando-se a completa ausência de solventes orgânicos nesta formulação. O estado de agregação do AMB foi avaliado por meio do espectro de absorção da luz UV-visível e a distribuição de tamanhos das formulações estudadas, determinadas por meio de analisador ZetaPlus Brookhaven Instruments Corporation, Holtsville, NY) equipado com um laser de 570 nm e dynamic light scattering (90ºC) para a medição dos tamanhos (Grabowski & Morrison, 1983). AMB foi estabilizada na bicamada de DODAB em forma monomérica, eliminando-se os grandes agregados de AMB insolúveis em água. Tanto a sobrevida dos animais como os experimentos com recuperação das leveduras dos órgãos colonizados (baço e rins) mostraram eficácia equivalente à demonstrada por Fungizona (DOC/AMB) - a sobrevida foi de 100 e 70% respectivamente nas concentrações de 0.4 mg/kg/dia via i.p. por 10 dias (P>0.05), em relação a eliminação da colonização de C. albicans dos rins e baço. Em resumo, DOD/AMB foi efetivo no tratamento de candidíase sistêmica em modelo animal.

DOD/AMB: in vivo activity of a novel amb formulation with synthetic cationic bilayer fragments

The ability of the versatile dioctadecyldimethylammonium bromide (DODAB), a bilayer-forming synthetic lipid previously shown to solubilize Amphotericin B (AMB), inspired this evaluation of in vivo activity of the DODAB/AMB formulation (DOD/AMB) against systemic candidiasis in a mouse model from survival and tissue burden experiments. AMB was simply added to a DODAB powder dispersion in water previously obtained by sonication with tip at concentrations 0.1 and 10 mg/mL, respectively, organic solvents completely absent. AMB aggregation state was evaluated from UV-visible light absorption and dynamic light scattering for aggregate sizing. AMB was stabilized by the DODAB bilayer fragments in its monomeric form, causing disappearance of large water insoluble drug aggregates. From survival and tissue burden experiments, DOD/AMB efficacy was equivalent to the one exhibited by Fungizone (DOC/AMB) - 100 and 70% survival respectively, at 0.4 mg/kg/day given i.p. for 10 days (P>0.05) -, regarding elimination of Candida colonization in spleen and kidneys. In summary, DOD/AMB, was effective for treating systemic candidiasis in a mouse model.

A habilidade do brometo de dioctadecildimetilamônio (DOBAB), em formar bicamada de lipídio sintético e a demonstração prévia do forte poder solubilizante de anfotericina B (ANB) , incentivou-nos a realizar a avaliação da atividade de DODAB/AMB in vivo contra candidíase sistêmica em modelo de camundongos para verificar a sua sobrevida bem como a recuperação das leveduras de C. albicans dos órgãos colonizados (baço e rins). O AMB foi simplesmente adicionado à DODAB em pó previamente disperso em água e sonicado com auxílio de ponteiras, nas concentrações de 0,1e 10 mg/mL, respectivamente, assegurando-se a completa ausência de solventes orgânicos nesta formulação. O estado de agregação do AMB foi avaliado por meio do espectro de absorção da luz UV-visível e a distribuição de tamanhos das formulações estudadas, determinadas por meio de analisador ZetaPlus Brookhaven Instruments Corporation, Holtsville, NY) equipado com um laser de 570 nm e dynamic light scattering (90ºC) para a medição dos tamanhos (Grabowski & Morrison, 1983). AMB foi estabilizada na bicamada de DODAB em forma monomérica, eliminando-se os grandes agregados de AMB insolúveis em água. Tanto a sobrevida dos animais como os experimentos com recuperação das leveduras dos órgãos colonizados (baço e rins) mostraram eficácia equivalente à demonstrada por Fungizona (DOC/AMB) - a sobrevida foi de 100 e 70% respectivamente nas concentrações de 0.4 mg/kg/dia via i.p. por 10 dias (P>0.05), em relação a eliminação da colonização de C. albicans dos rins e baço. Em resumo, DOD/AMB foi efetivo no tratamento de candidíase sistêmica em modelo animal.