INVESTIGATION OF BIOFILM FORMATION IN COAGULASE-NEGATIVE STAPHYLOCOCCI ISOLATED FROM PLATELET CONCENTRATE BAGS

Platelet Concentrates (PCs) are the blood components with the highest rate of bacterial contamination, and coagulase-negative staphylococci (CoNS) are the most frequently isolated contaminants. This study investigated the biofilm formation of 16 contaminated units out of 691 PCs tested by phenotypic and genotypic methods. Adhesion in Borosilicate Tube (ABT) and Congo Red Agar (CRA) tests were used to assess the presence of biofilm. The presence of icaADC genes was assessed by means of the Polymerase Chain Reaction (PCR) technique. With Vitek(r)2, Staphylococcus haemolyticus was considered the most prevalent CoNS (31.25%). The CRA characterized 43.8% as probable biofilm producers, and for the ABT test, 37.5%. The icaADC genes were identified in seven samples by the PCR. The ABT technique showed 85.7% sensitivity and 100% specificity when compared to the reference method (PCR), and presented strong agreement (k = 0.8). This study shows that species identified as PCs contaminants are considered inhabitants of the normal skin flora and they might become important pathogens. The results also lead to the recommendation of ABT use in laboratory routine for detecting biofilm in CoNS contaminants of PCs

Atividade in vitro da secreção de Lucilia cuprina frente à Leishmania amazonensis, Ttrypanosoma cruzi e linhagens celulares / In vitro activity of larval secretions from Lucilia cuprina against Leishmania amazonensis, Trypanosoma cruzi and cell lines

As pesquisas com produtos naturais representam um valioso recurso, pois são fonte de compostos biologicamente ativos que podem ter atividade contra uma variedade de patógenos que afetam a saúde humana e animal. Os dípteros da espécie Lucilia cuprina, pertencente à família Calliphoridae, conhecidos como moscas varejeiras, são cosmopolitas e têm importante função na natureza devido ao desenvolvimento de suas larvas em matéria orgânica em decomposição. Alguns estudos chegaram à conclusão de que a produção de enzimas digestivas secretadas pelas larvas são importantes para o estabelecimento e  sobrevivência desses insetos no hospedeiro e no ambiente  devido a sua  secreção ter ação bactericida, antiparasitária e antifúngica e ao hábito alimentar necrobiontófago, esses dipteros têm sido utilizados em bioterapia e pesquisas contra vários patógenos, entretanto, são poucos os estudos com foco na secreção desta espécie. Portanto, o objetivo deste trabalho foi verificar a atividade da secreção larval in vitro de L. cuprina, extraída de larvas L3 em diferentes concentrações por um período de 24 horas, frente à Leishmania amazonensis, Trypanosoma cruzi, linhagem tumoral de melanoma B16-F10 e HFF-1 de fibroblasto humano. Evidenciou-se uma redução na viabilidade de promastigotas de L. amazonensis nos tratamentos com secreção larval de 0,25%, 1% e 2% (viabilidade reduzida para 43,33%, 60% e 37,33% respectivamente). No ensaio com T. cruzi as concentrações 0,25% e 0,5% de secreção larval foi ativa mostrando diminuição de viabilidade de epimastigotas para 35,28% e 43,07%. A secreção larval mostrou capacidade citotóxica para as células tumorais. A concentração de 2% foi significativa em todos os ensaios, MTT, Vermelho Neutro (NR) e Crystal Violeta (VC), com redução de viabilidade para 79,3%, 85% e 85,6%, respectivamente. O tratamento a 1% mostrou diferença significativa tanto para NR (viabilidade de 74%) como VC (viabilidade de 83,6%). A concentração de 0,5% no NR diminuiu viabilidade para 80,6%. Nos ensaios com linhagem não tumoral a secreção mostrou baixa toxicidade, demonstrando segurança. O ensaio fluorimétrico realizado para quantificação de dsDNA (Picogreen) indicou um aumento de 14% à 25% de DNA extracelular. Os resultados fluorimétricos com o marcador 2,7’-diclorofluoresceína (DCFH-DA) mostraram um aumento de 20% e 22% de espécies reativas nas concentrações de 0,25 e 2%, sendo indicativo de um possível mecanismo de morte celular por radicais livres. Os resultados revelam que a secreção larval de L. cuprina, em diferentes concentrações, demonstrou atividade antiprotozoária e citotóxica na linhagem tumoral

Complexos triazenidos de platina (II): Avaliação in vitro da atividade antibacteriana e citotóxica frente a bactérias e células de medula óssea de pacientes leucêmicos de um hospital escola

<p>Atualmente, apesar da ampla gama de substâncias ativas existentes, progressivamente tem se limitado o arsenal terapêutico disponível na prática clínica, isto se deve, especialmente, pelo surgimento da resistência aos agentes terapêuticos utilizados no tratamento de tumores e infecções bacterianas. Em virtude das diversas propriedades farmacológicas demonstradas pelos triazenos (TZCs), avaliaram-se compostos inéditos na busca de novos agentes biologicamente ativos, estes foram denominados C1 e C2. A atividade antibacteriana foi realizada pelo método convencional da microdiluição em caldo, através da técnica da Concentração Inibitória Mínima (CIM), frente a cepas bacterianas de referência American Type Culture Collection (ATCC) e isolados clínicos com resistência múltipla as drogas (RMD). A citotoxicidade foi analisada através do ensaio colorimétrico baseado na redução do brometo de 3-(4,5-dimetiltiazol-2-il)-2,5–difeniltetrazólio frente a células da medula óssea de dois pacientes (P1 e P2) atendidos no Hospital Universitário de Santa Maria. Os dois compostos testados apresentaram atividade antibacteriana em 26,08% (6/23) das cepas testadas, sendo ativos em 38,46% (5/13) das cepas ATCC e 10% (1/10) dos isolados clínicos RMD, apenas em espécies caracterizadas como Gram positivas. Os resultados foram satisfatórios para ambos os compostos frente à amostra P2, células mononucleares de Leucemia Mielóide Crônica, pois demonstraram indução da morte celular. Pode-se concluir que os resultados obtidos desses compostos demonstraram a existência de atividade antibacteriana, bem como, atividade antileucêmica promissora. Pesquisas complementares relacionadas a esses compostos estão em andamento.</p><p>Palavras-chave: Triazeno. Citotoxicidade. Atividade Antibacteriana. Platina.</p><p> </p><p>ABSTRACT</p><p> </p><p>Currently, despite the wide range of existing active substances has been progressively limited therapeutic arsenal available in clinical practice, this is, in particular, the emergence of resistance to therapeutic agents used in treating tumors and bacterial infections. Because of the diverse pharmacological properties demonstrated by triazenes (TZCs) - evaluated whether unpublished compounds in the search for new biologically active agents, they were called C1 and C2. The antibacterial activity was performed by the conventional method of broth microdilution, using the technique of Minimum Inhibitory Concentration (MIC) against the bacterial strains reference American Type Culture Collection (ATCC) and clinical isolates with multiple drug resistance (MDR). Cytotoxicity was analyzed by colorimetric assay based on the reduction of the bromide of 3 - (4,5- dimethylthiazol-2- yl) -2,5- diphenyltetrazolium against bone marrow cells from two patients (P1 and P2) seen at the Hospital university of Santa Maria. The two compounds tested showed antibacterial activity in 26.08% (6/23) of the strains, being active in 38.46 % (5/13) of the ATCC strains and 10 % (1/10) of clinical isolates MDR only characterized in species such as Gram positive. The results were satisfactory for both the sample compounds front P2, mononuclear cells from chronic myeloid leukemia, as demonstrated induction of cell death. It can be concluded that the results demonstrated the existence of these compounds to antibacterial activity, as well as promising antileukemic activity. Additional research related to these compounds are in progress.</p><p>Keywords: Triazenes. Cytotoxicity. Antibacterial Activity. Platinum.</p

Staphylococcal scalded skin syndrome in a premature newborn caused by methicillin-resistant Staphylococcus aureus: case report

CONTEXT: Staphylococcal scalded skin syndrome is an exfoliative skin disease. Reports of this syndrome in newborns caused by methicillin-resistant Staphylococcus aureus are rare but, when present, rapid diagnosis and treatment is required in order to decrease morbidity and mortality. CASE REPORT: A premature newly born girl weighing 1,520 g, born with a gestational age of 29 weeks and 4 days, developed staphylococcal scalded skin syndrome on the fifth day of life. Cultures on blood samples collected on the first and fourth days were negative, but Pseudomonas aeruginosa and Enterococcus sp. (vancomycin-sensitive) developed in blood cultures performed on the day of death (seventh day), and Pseudomonas aeruginosa and Serratia marcescens were identified in cultures on nasopharyngeal, buttock and abdominal secretions. In addition to these two Gram-negative bacilli, methicillin-resistant Staphylococcus aureus was isolated in a culture on the umbilical stump (seventh day). The diagnosis of staphylococcal scalded skin syndrome was based on clinical criteria

Synthesis, characterization and biological activity of a gold(I) triazenide complex against chronic myeloid leukemia cells and biofilm producing microorganisms

<div><p>ABSTRACT The enhancement of anti-leukemia therapy and the treatment of infections caused by multidrug-resistant pathogens are major challenges in healthcare. Although a large arsenal of drugs is available, many of these become ineffective, and as a result, the discovery of new active substances occurs. Notably, triazenes (TZCs) have been consolidated as a promising class of compounds, characterized by significant biological activity, especially antiproliferative and antimicrobial properties. The aim of this study is the synthesis and characterization of a new triazenide complex of gold (I), as well as the in vitro assessment of its antiproliferative activity against the K562 cell line (Chronic Myeloid Leukemia), and antibacterial activity against bacterial isolates of biofilm-producing coagulase-negative staphylococci. The combination of TZC with gold metal tends to have a synergistic effect against all biofilm-producing isolates, with Minimum Inhibitory Concentration values (MIC) between 32 and 64 µg mL-1. It has also shown activity against K562 cell line, getting an IC50=4.96 µM. Imatinib mesylate (Glivec) was used as reference, with IC50=3.86 µM. To the best of our knowledge, this study represents the first report of the activity of a TZC complexed with gold ion in the oxidation state (I) against microorganisms that produce biofilm and K562 cells.</p></div

Assessment of different methods for the detection of biofilm production in coagulase-negative staphylococci isolated from blood cultures of newborns

Abstract INTRODUCTION: Coagulase-negative staphylococci (CoNS) are a frequent cause of bacteremia, especially in neonates. The major virulence determinant in CoNS is the ability to produce biofilms, which is conferred by the icaADBC genes. This study aimed to assess different methods for the detection of biofilm formation in 176 CoNS isolates from blood cultures of newborns. METHODS: The presence of the icaACD genes was assessed by polymerase chain reaction (PCR), and biofilm formation was assessed on congo red agar (CRA), by the tube method (TM), and on tissue culture plates (TCP). RESULTS: Of the 176 CoNS isolates, 30.1% expressed icaACD and 11.4% expressed icaAD. The CRA assay and TM showed that 42% and 38.6% of the isolates were biofilm producing, respectively. On TCP, 40.9% of the isolates produced biofilms; 21% were weakly adherent and 19.9% were strongly adherent. When compared to the gold standard technique (PCR), the CRAassay showed 79% sensitivity and 84% specificity (kappa = 0.64), TM showed 78% sensitivity and 89% specificity (kappa = 0.68), and TCP showed 99% sensitivity and 100% specificity (kappa = 0.99). CONCLUSIONS: In this study, ~42% of CoNS isolates produced biofilms, and the presence of icaACD was associated with a greater capacity to form biofilms. Compared to the other phenotypic methodologies, TCP is an ideal procedure for routine laboratory use