Nocardiose: visão geral e relato de 28 casos em vacas e cães

Phenotypic characteristics, antimicrobial susceptibility profile, and clinical-epidemiological features of 28 Nocardia strains isolated from 19 cases of bovine mastitis, eight cutaneous-subcutaneous lesions and one case of pneumonia in dogs were evaluated. Microbiological, biochemical, cytological and scanning electron microscopy methods were used in diagnosis. Nocardia asteroides type IV, Nocardia otitidiscaviarum,Nocardia nova (type III) and Nocardia farcinica (type V) were isolated from bovine milk, bronchial lavage and/or cutaneous-subcutaneous abscesses in dogs. Nocardial bovine mastitis was diagnosed predominantly in clinical cases, in dairy herds with poor environmental hygienic conditions between milking and inappropriate intramammary therapy. Canine nocardiosis was observed commonly in animals co-infected with distemper virus. Sulphamethoxazole-trimethoprim (92.8%), amikacin (92.8%) and ceftiofur (92.8%) were the most effective drugs in 28 isolates. Multiple drug resistance to three or more and five or more antimicrobials was observed in ten (35.7%) and three (10.7%) strains, respectively, predominantly with use of cloxaxillin, cefoperazone and ampicillin. The species (type) classification, clinical-epidemiological characteristics, diagnosis, multiple-drug resistance and public health considerations in Nocardia strains isolated from cattle and dogs in Brazil are discussed, with special reference to report of bovine mastitis by N. otitidiscaviarum by first time in Brazil and the similarity between Nocardia species isolated from human and animal origin.A caracterização fenotípica, perfil de sensibilidade aos antimicrobianos e aspectos clínico-epidemiológicos foram avaliados em 28 linhagens de Nocardia isoladas de 19 casos de mastite, oito lesões tegumentares e um caso de pneumonia em cão. Foram utilizados no diagnóstico métodos microbiológicos, bioquímicos, citológicos e microscopia eletrônica de varredura. Nocardia asteroides tipo IV, N. otitidiscaviarum,N. nova (tipo III) e N. farcinica (tipo V) foram isoladas do leite de vacas com mastite, de material de lavado transtraqueal e de lesões cutâneas de cães. Nocardiose mamária bovina foi diagnosticada predominantemente sob a forma clínica, em propriedades com precárias condições de higiene na pré e pós-ordenha, e inadequado procedimento de terapia intramamária. Nocardiose canina foi diagnosticada comumente em animais co-infectados com o vírus da cinomose. Sulfametoxazole/trimetoprim (92,8%), amicacina (92,8%) e ceftiofur (92,8%) foram os antimicrobianos mais efetivos frente às linhagens de Nocardia. Resistência múltipla a três ou mais e cinco ou mais antimicrobianos foram observadas, respectivamente, em dez (35,7%) e três (10,7%) linhagens, notadamente frente à cloxacilina, cefoperazona e ampicilina. A caracterização de espécies (tipo), aspectos clínico-epidemiológicos, diagnóstico, resistência múltipla aos antimicrobianos e reflexos em saúde pública de linhagens de Nocardia isoladas de bovinos e cães no Brasil foram discutidos. Foi destacada a similaridade entre as espécies de Nocardia isoladas de animais e do homem, e a primeira descrição no Brasil de N. otitidiscaviarum na etiologia da mastite bovina

Detección de enterobacterias multirresistentes aisladas en aguas de los ríos que desembocan en la bahía de Guanabara y en muestras de hospitales de Río de Janeiro, Brasil

Introduction: The use of antibiotics in humans, animal husbandry and veterinary activities induces selective pressure leading to the colonization and infection by resistant strains.Objective: We evaluated water samples collected from rivers of the Guanabara Bay, which have suffered minor and major environmental degradation, and clinical samples of hospital origin to detect evidence of the presence of resistance genes to aminoglycosides, beta-lactam antibiotics and fluoroquinolones in strains of Klebsiella pneumoniae subsp. pneumoniae, K. pneumoniae subsp. ozaenae and Escherichia coli.Materials and methods: For isolation of the water strains we employed culture media containing 32 μg/ml cephalotin and 8 μg/ml gentamicin. The strains from clinical materials were selected using culture media containing 8 μg/ml gentamicin. The strains were identified and subjected to antimicrobial susceptibility testing (AST), plasmid DNA extraction and polymerase chain reaction (PCR) to detect genes encoding enzymes modifying aminoglycosides (EMA), extended-spectrum beta-lactamases (ESBL) and plasmid mechanisms of quinolone resistance (PMQR).Results: The AST of the isolates recovered from water samples showed multidrugresistance profiles similar to those found in isolates recovered from clinical materials. All isolates from water samples and 90% of the isolates from clinical samples showed at least one plasmid band. In the PCR assays, 7.4% of the isolates recovered from water samples and 20% of those from clinical materials showed amplification products for the three antimicrobial classes.Conclusion: We believe that the detection of microorganisms presenting genetic elements in environments such as water is necessary for the prevention and control of their dissemination with potential to infect humans and other animals in eventual contact with these environments.Introducción. El uso de antibióticos en seres humanos, en la industria pecuaria y en las actividades veterinarias induce una presión selectiva que resulta en la colonización e infección con cepas resistentes.Objetivo. Determinar la presencia de genes de resistencia a aminoglucósidos, betalactámicos y fluoroquinolonas en cepas de Klebsiella pneumoniae subsp. pneumoniae, K. pneumoniae subsp. ozaenae y Escherichia coli, obtenidas de muestras de agua de los ríos que desembocan en la bahía de Guanabara y de muestras clínicas de hospitales de Río de Janeiro. Materiales y métodos. En la selección de las cepas resistentes obtenidas de las muestras de agua de los ríos, se emplearon medios de cultivo que contenían 32 μg/ml de cefalotina y 8 μg/ml de gentamicina. En el caso de las muestras de especímenes clínicos, se usaron medios de cultivo que contenían 8 μg/ml de gentamicina. Las cepas se identificaron y se sometieron a pruebas de sensibilidad antimicrobiana, extracción de ADN plasmídico y pruebas de reacción en cadena de la polimerasa (PCR) para detectar los genes que codifican aquellas enzimas que modifican los aminoglucósidos, las betalactamasas de espectro extendido (BLEE) y los mecanismos de resistencia a las quinolonas mediados por plásmidos.Resultados. Se encontraron perfiles de resistencia a los antimicrobianos similares en los dos grupos. En todas las bacterias obtenidas de las muestras de agua y en 90 % de las muestras clínicas, se evidenciaron bandas de plásmidos asociados con la transferencia de genes de resistencia. En las pruebas de PCR, se obtuvieron productos de amplificación de los genes de resistencia para las tres clases de antimicrobianos analizados, en el 7,4 % de las bacterias recuperadas de las muestras de agua y en el 20 % de aquellas recuperadas de las muestras clínicas.Conclusión. La detección de microorganismos con elementos genéticos que confieren resistencia a los antibióticos en ambientes como el agua, es una estrategia necesaria para prevenir y controlar la diseminación de estos agentes patógenos con potencial para infectar a humanos y a otros animales en dichos ambientes

Fibrinogen binds to nontoxigenic and toxigenic Corynebacterium diphtheriae strains

The production of fibrinous exudates may play an important role in determining the outcome of bacterial infection. Although pseudomembrane formation is a characteristic feature of diphtheria, little is known about the fibrinogen (Fbn)-binding properties of Corynebacterium diphtheriae strains and the influence of the gene that codes for diphtheria toxin (tox gene) in this process. In this study we demonstrated the ability of C. diphtheriae strains to bind to Fbn and to convert Fbn to fibrin. Bacterial interaction with rabbit plasma was evaluated by both slide and tube tests. Interaction of microorganisms with human Fbn was evaluated by both enzyme linked immunosorbent assay (ELISA) and fluorescein isothiocyanate-conjugated (FITC) Fbn binding assays. Nontoxigenic and toxigenic strains formed bacterial aggregates in the presence of plasma in the slide tests. The ability to convert Fbn to a loose web of fibrin in the plasma solution in the tube tests appeared to be a common characteristic of the species, including strains that do not carry the tox gene. Fbn binding to C. diphtheriae strains occurred at varying intensities, as demonstrated by the FITC-Fbn and ELISA binding assays. Our data suggest that the capacity to bind to Fbn and to convert Fbn to fibrin may play a role in pseudomembrane formation and act as virulence determinants of both nontoxigenic and toxigenic strains

Protocol of scoping review: hemolysins as a virulence factor in the pathogenesis of Mycobacterium and Corynebacterium diphtheriae infections

Hemolysins are cytolytic exotoxins of a protein nature that damage the membranes of endothelial cells and blood cells, particularly erythrocytes, fibroblasts, lymphocytes, and monocytes, disrupting the function of the plasma membrane and causing cell death (MAGALHÃES et al., 2011). Several bacterial species use blood cell lysis as a relevant virulence factor: Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Treponema hyodysenteriae, Helicobacter pylori, Serratia marcescens, Vibrio parahemolyticus, as well as different species of Mycobacterium spp. causing diverse infections, including urinary tract infections, peritonitis, appendicitis, septicemia, and neonatal meningitis (BIEN; SOKOLOVA; BOZKO, 2012; DEVAL et al., 2016; GEBISA; GERASU; LEGGESE, 2019; HUANG et al., 2022; RAHMAN et al., 2010). Some studies have linked E. coli hemolysin A with colorectal cancer and adenoma genesis (growth of benign glands that can evolve into adenocarcinoma) in women, even indicating a poor prognosis for these tumors (JIN et al., 2016). In addition, one study showed that 26% of the samples isolated from the feces of patients with cancer associated with bacteremia were identified as hemolysin-producing E. coli (HILALI et al., 2000). Corynebacterium diphtheriae (C. diphtheriae) is the main aetiological agent of diphtheria. Despite vaccination and the significant knowledge acquired over the years, the strategies available to eradicate it are still insufficient (SABBADINI et al., 2010). Inequalities in vaccination coverage, especially infant vaccination, and reproductive and maternal health are significantly worse in conflict-affected countries (AKSEER et al., 2020), and are one of the main explanations for the spread of diphtheria and other vaccine-preventable diseases among refugees. This data, combined with the lack of adequate health infrastructure, greater resistance to antimicrobials, lower vaccination coverage, and the economic crisis, factors that have been further exacerbated by the COVID-19 pandemic, suggest a worldwide rise in the resurgence of vaccine-controlled diseases in the coming years (AKSEER et al., 2020; CUCINELLI et al., 2021; DOOCY et al., 2019; TRUELOVE et al., 2020). In addition, atypical infections caused by non-producers of diphtheria toxin (TD) strains of C. diphtheriae have been increasingly reported (SANTOS et al., 2014; VIGUETTI et al., 2012), which suggests that other virulence factors may be expressed by pathogenic strains in addition to TD production (HIRATA-JUNIOR. et al., 2008; VIEIRA et al., 2022). Non-TD-producing strains of C. diphtheriae are also capable of causing infections such as severe pharyngitis and tonsillitis, as well as invasive infections such as endocarditis (CLINTON et al., 2013; HIRATA-JUNIOR. et al., 2008; MUTTAIYAH et al., 2011; SANTIS et al., 2020), bacteremia (GOMES et al., 2009; KATO et al., 2020; MATTOS-GUARALDI et al., 2001; ZASADA et al., 2005), pneumonia (TROST et al., 2012; YANG et al., 2018), septic arthritis (DIAS et al., 2011b; PEIXOTO et al., 2017; PULITI et al., 2006), splenic abscess (ALEXANDER, 1984) and osteomyelitis (PEIXOTO et al., 2016; POILANE et al., 1995), even leading to death. Some strains of C. diphtheriae appear to produce specific hemolysins, as they are classified according to their hemolytic activity. Genome sequencing of C. diphtheriae strain NCTC 13129 identified the sequence of a hypothetical hemolysin-like protein (TlyA) from Mycobacterium tuberculosis (M. tuberculosis). However, little is known about the role of hemolysins in the pathogenesis of diphtheria (CERDEÑO-TÁRRAGA et al., 2003; TROST et al., 2012). The TlyA proteins discovered in different species of mycobacteria, M. tuberculosis, Mycobacterium marinum, Mycobacterium leprae, Mycobacterium lepromatosis, and Mycobacterium uberis, may have a dual activity as a hemolysin and as an S-adenosylmethionine (SAM)-dependent rRNA methylase. Numerous mycobacterial virulence factors have been characterized, but information on the TlyA protein is still limited in terms of molecular and structural characterization. The genomic knowledge provided by comparative analysis of TlyA sequences and its conserved domains reveals pore-forming activity, which further confirms its role as a virulence protein (Sharma & Singh, 2022). M. tuberculosis is the bacillus that causes the disease called tuberculosis, which is responsible for millions of deaths a year worldwide. Currently, tuberculosis is the second deadliest infectious disease (after COVID-19) (OPAS, 2023). The hemolytic protein TlyA of M. tuberculosis may function as a virulence determinant, as it has shown homology with the products of the tlyA gene of the swine pathogen Serpulina hyodysenteriae, a causative agent of swine dysentery, and is almost identical to the tlyA gene of Mycobacterium leprae (M. leprae), leprosy causative agent (Rahman et al, 2010). In addition, it has been reported that in M. tuberculosis the function of S-adenosylmethionine (SAM)-dependent rRNA methylase may be related to resistance to the antibiotic capreomycin. The antibiotic capreomycin is used clinically against several drug-resistant strains of M. tuberculosis. It targets the complex between TlyA, a haemolysin and RNA-binding protein, and bacterial rRNA. Thus, capreomycin binds to the bacterial ribosome, forming a complex in which the ribosomal subunits, large and small, interact in M. tuberculosis using an S-adenosylmethionine-dependent methyltransferase, TlyA (Ali et al, 2022; Sukati et al, 2022). Recent studies on Helicobacter pylori (H. pylori) strains have also demonstrated the effect of capreomycin on the SAM activity of TlyA (Sukati et al, 2022). Corynebacterium diphtheriae and some strains appear to produce hemolysins specific, since they are classified according to hemolytic activity. O genomic sequencing of C. diphtheriae strain NCTC 13129 identified the sequence of a hypothetical protein, similar to hemolysin (TlyA) of Mycobacterium tuberculosis. However little is known about the role of hemolysins in the pathogenesis of diphtheria. In this context, we aim to answer the question: What is known about hemolysins as a virulence factor in the pathogenesis of Mycobacterium and C. diphtheriae infections

Propriedades antibacterianas e anticariogênicas do xilitol: uma revisão da literatura

Objective: the purpose of this study was to review some properties of xylitol as an antimicrobial agent and the role of this sugar alcohol in the prevention and control of dental caries activity. Material and Methods: the study was based on PubMed scientific papers, in addition of evaluating older researches, to obtain a more complete view of this polyol, encompassing its biochemical, antibacterial, antibiofilm and toxic properties, as well as its different forms of use. Results: the study carried out highlighted the positive characteristics of xylitol in relation to its use in humans and its possible therapeutic use as a substance for the prevention and control of caries disease. Conclusion: It was concluded that, though the scientific documentation that reinforce its efficiency in caries prevention, some authors still do not consider the clinical evidence as satisfactory about the effects of xylitol, and recommend better controlled clinical investigations, especially in relation to the prolonged use of this polyol, in order to provide more conclusive data.o objetivo deste estudo foi rever algumas propriedades da xilitol como um agente antimicrobiano e o papel deste álcool no açúcar na prevenção e controle da atividade de cárie dentária. Material e métodos: o estudo foi baseado em trabalhos científicos PubMed, além de avaliar pesquisas mais antigas, para obter uma visão mais completa deste poliol, englobando suas propriedades bioquímicas, antibacterianas, antifilmáveis e tóxicas, bem como a sua diferentes formas de uso. Resultados: o estudo realizado destacou as características positivas da xilitol em relação ao seu uso em humanos e seu possível uso terapêutico como substância para a prevenção e controle da doença cárie. Conclusão: concluiu-se que, embora a documentação científica que reforça a sua eficiência na prevenção de cáries, alguns autores ainda não consideram a evidência clínica como satisfatória sobre os efeitos da xilitol, e recomendar melhor controlada investigações clínicas, especialmente em relação ao uso prolongado deste poliol, a fim de fornecer dados mais conclusivos

Central venous catheter-related infections caused by Corynebacterium amycolatum and other multiresistant non-diphtherial corynebacteria in paediatric oncology patients

ABSTRACT Bloodstream and venous catheter-related corynebacterial infections in paediatric patients with haematological cancer were investigated from January 2003 to December 2014 at the Brazilian National Cancer Institute in Rio de Janeiro, Brazil. We observed that during cancer treatment, invasive corynebacterial infections occurred independent of certain factors, such as age and gender, underlying diseases and neutropenia. These infections were ssscaused by Corynebacterium amycolatum and other non-diphtherial corynebacteria. All cases presented a variable profile of susceptibility to antimicrobial agents, except to vancomycin. Targeted antibiotic therapy may contribute to catheters maintenance and support quality of treatment. Non-diphtherial corynebacteria must be recognized as agents associated with venous access infections. Our data highlight the need for the accurate identification of corynebacteria species, as well as antimicrobial susceptibility testing

Distribution of PLD and FagA, B, C and D genes in Corynebacterium pseudotuberculosis isolates from sheep and goats with caseus lymphadenitis

Caseous lymphadenits (CL) is a chronic and subclinical disease that affects goats and sheep and, consequently, causes economic losses, especially to small producers. The purpose of this study, through use of Polymerase Chain Reaction (PCR), was to verify the presence of virulence genes of phospholipase D (PLD), integral membrane protein (FagA), iron enterobactin transporter (FagB), ATP binding cytoplasmic membrane protein (FagC) and iron siderophore binding protein (FagD) in 168 isolates of C. pseudotuberculosis obtained from cases of caseous lymphadenitis in goats and sheep. FagA, FagB and PLD genes were detected in all 145 strains isolated from abscesses in superficial lymph nodes and in 23 strains isolated from viscera. The FagC gene was positive in 167 (99.40%) isolates. The FagD gene was detected in 160 (95.23%) isolates. All virulence factors analyzed were found more frequently among isolates collected in the viscera of animals with CL, indicating a multifactorial nature, as well as variations, in the invasive potential of C. pseudotuberculosis strains

Short Report: Identification of Virulence-Associated Plasmids in Rhodococcus equi in Humans with and without Acquired Immunodeficiency Syndrome in Brazil

Virulence of Rhodococcus equi strains from 20 humans in Brazil was investigated by using a polymerase chain reaction to characterize isolates as virulent (VapA), intermediately virulent (VapB), and avirulent. Nine isolates were obtained from human immunodeficiency virus (HIV)-positive patients, six from HIV-negative patients, and five from patients of unknown status. Five isolates were VapB positive, four were VapA positive, and eleven were avirulent. Among the nine isolates from HIV-positive patients, five contained VapB plasmids and two contained VapA plasmids. Five VapB-positive isolates had the type 8 virulence plasmid. Eleven of the patients had a history of contact with livestock and/or a farm environment, and none had contact with pigs.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP