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.

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

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.

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.

Staphylococcal scalded skin syndrome in a premature newborn caused by methicillin-resistant Staphylococcus aureus: case report / Síndrome da pele escaldada estafilocócica em um recém-nascido prematuro causada por Staphylococcus aureus meticilina-resistente: relato de caso

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.

CONTEXTO: A síndrome da pele escaldada estafilocócica é uma doença esfoliativa de pele. São raros os relatos desta síndrome causada por Staphylococcus aureusresistente à meticilina em neonatos, mas, quando presentes, exigem diagnóstico e tratamento rápidos para diminuir a morbidade e mortalidade. RELATO DE CASO: Uma menina recém-nascida prematura, pesando 1.520 g ao nascimento, com idade gestacional de 29 semanas e 4 dias, desenvolveu síndrome da pele escaldada estafilocócica no quinto dia de vida. As culturas de sangue coletadas no primeiro e quarto dias foram negativas, mas houve desenvolvimento de Pseudomonas aeruginosa e Enterococcus sp. (vancomicina sensível) na hemocultura realizada no dia do óbito (sétimo dia) e Pseudomonas aeruginosa e Serratia marcescens foram identificadas nas culturas de secreção da nasofaringe, nádega e da secreção abdominal. Na cultura do coto umbilical (sétimo dia), além desses dois bacilos Gram-negativos, foi isolado o Staphylococcus aureus resistente à meticilina. O diagnóstico da síndrome da pele escaldada estafilocócica foi baseado em critério clínico.

Análise do Perfil de Sensibilidade frente aos antimicrobianos de bactérias isoladas de bacteremias em um hospital universitário / Análisis de la susceptibilidad de los antimicrobianos frente a bacterias aisladas de bacteriemias en un hospital universitario / Analysis of the antimicrobial susceptibility profile of bacteria isolated from bacteriemias in a university hospital

Introdução: bacteremia é uma das complicações mais frequentes e graves que acometem, principalmente pacientes imunodeprimidos. É responsável por prolongar o período de hospitalização e está associada com elevadas taxas de morbidade e mortalidade dos pacientes internados. Objetivo: identificar os microrganismos associados à bacteriemia e analisar seu perfil de sensibilidade frente aos antimicrobianos em um Hospital Terciário. Métodos: foi realizado um estudo retrospectivo e transversal, no qual foram incluídas todas as hemoculturas em que houve o crescimento de microrganismos viáveis. Resultados: um total de 1080 amostras foram avaliadas neste estudo. O patógeno mais isolado foi o Staphylococcus epidermidis (24 por cento/n=259), seguido do Staphylococcus hominis (6,8 por cento/n=74). Todas as bactérias Gram-positivas foram sensíveis frente à daptomicina, tigeciclina, linezolida e vancomicina. Além do mais, 42,31 por cento dos isolados do gênero Staphylococcus foram caracterizados fenotipicamente como Staphylococcus coagulase negativa resistentes à meticilina (MRSCoN). Conclusão: a maioria das bacteremias foram ocasionadas por Staphylococcus coagule negativos (SCoN). Entre esses, uma taxa considerável foi resistente à meticilina. Dessa forma, o antibioticoterapia deveriam ser reconsiderados, principalmente nos pacientes que sobem a bordo escolas nas unidades críticas(AU)

Introducción: La bacteriemia es una de las complicaciones más comunes y graves que afectan principalmente a pacientes inmunocomprometidos. Incrementa la hospitalización y se relaciona con una alta morbilidad y mortalidad. Objetivo: identificar los microorganismos asociados con bacteriemia y analizar su perfil de susceptibilidad antimicrobiana en un hospital de tercer nivel. Métodos: estudio retrospectivo y transversal que incluyó todos los hemocultivos que mostraron crecimiento de microorganismos viables. Se estudiaron 1080 cultivos. Resultados: El organismo más aislado fue Staphylococcus epidermidis (24 por ciento / n = 259), seguido por Staphylococcus hominis (6,8 por ciento / n = 74). Todas las bacterias grampositivas fueron susceptibles a la daptomicina, tigecyline, vancomicina y linezolid. Por otro lado, el 42,31 por ciento de Staphylococcus coagulasa negativos aislados se caracterizaron fenotípicamente como resistente a la meticilina (MRSCon). Conclusiones: la mayoría de las bacteriemias fueron causadas por Staphylococcus coagulasa negativo con una importante resistencia a la meticilina; en consecuencia, la institución debe volver a analizar el tratamiento antibiótico principalmente para pacientes hospitalizados en unidades de cuidados críticos(AU)

Introduction: bacteremia is one of the most common and serious complications that mainly affect immunocompromised patients. It accounts for the extension of hospitalization and is related to high morbidity and mortality rates in inpatients. Objective: to identify microorganisms associated with bacteremia and to analyze their antimicrobial susceptibility profile in a tertiary hospital. Methods: retrospective and cross-sectional study including all the hemocultures that showed viable microorganism growth. Results: one thousand eighty samples were evaluated in this study. The most isolated pathogen was Staphylococcus epidermidis (24 percent/n=259), followed by Staphylococcus hominis (6.8 percent/n=74). All Gram-positive bacteria were susceptible to Daptomycin, Tigecyline, Vancomycin and Linezolid. On the other hand, 42.31 percent of the isolated Coagulase-negative Staphylococcus were phenotipically characterized as methicillin-resistant (MRSCon). Conclusions: the majority of bacteriemias was caused by Coagulase negative Staphylococcus with significant methicillin-resistance; consequently, the institution must reanalyze the antibiotic treatment mainly for hospitalized patients in critical care units(AU)

Atividade antibacteriana de um composto triazenido com ouro frente a cepas bacterianas e isolados clínicos / Actividad antibacteriana de un triazenido compuesto de oro frente a las cepas bacterianas y los aislados clínicos / Antibacterial activity of gold complexed triazenid against bacterial strains and clinical isolates

Introdução: de uma forma alarmante, estudos demonstraram que nos últimos anos ocorreu um grande aumento na resistência bacteriana frente aos antibióticos. Consequentemente, há uma grande necessidade de descoberta de novas substâncias ativas, e entre essas, os compostos triazenos vêm demonstrado-se como uma classe promissora de metalofármacos, com significativa atividade antimicrobiana. Além do mais, a associação do radical farmacofórico triazenos com metais, como o ouro, favorece a produção de moléculas com maior atividade biológica. Objetivo: avaliar a atividade antibacteriana in vitro do composto triazenos inédito complexado com ouro no estado de oxidação I {(1-(2-bromofenil)-3-(2-nitrofenil)triazenido(trifenilfosfina)ouro(I)}, frente a cepas bacterianas padrões de referência American Type Culture Collection e isolados clínicos com resistência múltipla as drogas (MDR). Métodos: a atividade antibacteriana do composto triazenos foi determinada através do método de Concentração Inibitória Mínima, baseado no Clinical and Laboratory Standards Institute de 2012. A CIM foi caracterizada visualmente, como a menor concentração que inibiu completamente o crescimento dos microrganismos nos poços de diluição. Resultados: o composto em estudo apresentou pronunciada atividade antibacteriana, sendo ativo em 43,4 por cento (10/23) das bactérias testadas, mostrando-se seletivo frente a cepas Gram positivas. Conclusão: o complexo triazenos apresentou estreito espectro de ação, sendo ativo somente frente aos microrganismos classificados como Gram positivos, demonstrando assim uma alternativa para a concepção de uma nova classe de metalofármacos com atividade antibacteriana(AU)

Introducción: de una manera alarmante, los estudios han demostrado que en los últimos años hubo un gran aumento de la resistencia bacteriana a los antibióticos. Por consiguiente, hay una gran necesidad para el descubrimiento de nuevas sustancias activas, y entre estas, los compuestos triazenos se muestran como una clase prometedora de metalofármacos con actividad antimicrobiana significativa. Por otra parte, la asociación de triazeno farmacóforo radical con metales como el oro favorece la producción de moléculas con actividad biológica superior. Objetivo: evaluar la actividad antibacteriana in vitro del compuesto sin precedentes triazeno complejado con oro en el estado de oxidación I {(1-(2-bromofenil)-3-(2-nitrofenil)triazenido(trifenilfosfina)ouro(I)}, frente a las cepas de las normas bacterianas, cepas de referencia American Type Culture Collection y los aislados clínicos con resistencia múltiple a los medicamentos. Métodos: la actividad antibacteriana del triazeno compuesto se determinó por el método de la concentración inhibitoria mínima, sobre la base de estándares clínicos y de laboratorio de 2012. Este método se caracteriza visualmente como la menor concentración que inhibió completamente el crecimiento de microorganismos en los pocillos de dilución. Resultados: el compuesto de ensayo mostró actividad antibacteriana pronunciada, el cual fue activo en 43,4 por ciento (10/23) de las bacterias ensayadas, uy mostró ser selectivo contra las cepas grampositivas. Conclusión: el complejo triazeno mostró estrecho espectro de acción, el cual es activo solo frente a los microorganismos clasificados como grampositivos, lo que demuestra una alternativa para la concepción de una nueva clase de metalofármacos con actividad antibacteriana(AU)

Introduction: several studies have revealed that the increase of bacterial resistance to antibiotic is really alarming in the last few years. Consequently, the discovery of new active substances is a must and the triazene compounds appear as a promising class of metal drugs with significant antimicrobial action. On the other hand, the association of radical pharmacophorous triazene with metals such as gold facilitates the production of greater biological action molecules. Objective: to evaluate the in vitro antibacterial activity of this unprecedented compound called gold complexed with triazene at oxidation state I {(1-(2-bromophenyl)-3-(2-nitrophenyl)triazenide (triphenylphosphane) gold(I)} against the bacterial standard strains, American Type Culture Collection reference strains and the multiple drug resistance clinical isolates. Methods: the antibacterial activity of the compound triazene was estimated by the minimal inhibitory concentration method on the basis of the clinical and laboratory standards 2012. This method is visually characterized as the lowest concentration that fully inhibited the bacterial growth in the dilution wells. Results: the tested compound showed significant antibacterial activity, being active in 43.4 percent (10/23) of tested bacteria and selective for Gram-positive strains. Conclusions: triazene complex showed narrow action spectrum since it is only active against Gram-positive microorganisms, which is in turn an alternative for conception of a new class of metal drugs with antibacterial action(AU)

Fasciite necrosante por Streptococcus agalactiae em paciente diabética ? relato de caso / Necrotizing fasciitis caused by Streptococcus agalactiae in a diabetic patient ? case report

Objetivos: Descrever um caso de fasciite necrosante e choque séptico ocasionado por Streptococcus agalactiae, que acometeu uma paciente com diabetes mellitus. Esta análise foi realizada através dos dados do prontuário e resultados de exames laboratoriais da paciente, que estava internada no Hospital Universitário de Santa Maria, em Santa Maria, Rio Grande do Sul.Descrição do caso: Paciente do gênero feminino, 73 anos, diagnosticada com diabetes mellitus e cirrose micronodular, foi internada com suspeita de septicemia, simultânea a uma infecção no membro inferior esquerdo, cuja hipótese diagnóstica inicial foi de celulite. Pelas características do quadro clínico, foi feito o diagnóstico de fasciite necrosante. Hemoculturas de dois sítios diferentes positivaram para S. agalactiae. A paciente foi a óbito por choque séptico.Conclusões: O relato deste caso enfatiza a gravidade da fasciite necrosante, que pode ocorrer principalmente em pacientes portadores de fatores predisponentes como diabetes mellitus e cirrose.

Aims: To report an unusual case of necrotizing fasciitis and septic shock caused by Streptococcus agalactiae, which affected a patient with diabetes mellitus. This analysis was performed using data from medical records and laboratory tests results, who was admitted to the University Hospital of Santa Maria, in Santa Maria, Rio Grande do Sul, Brazil.Case description: Female patient, 73 years old, diagnosed with diabetes mellitus and micronodular cirrhosis, was admitted with suspected septicemia simultaneous with an infection in the left lower limb, which initial diagnostic hypothesis was cellulitis. Based on characteristics of the clinical picture, the diagnosis of necrotizing fasciitis was done. Blood cultures from two different sites were positive for S. agalactiae. The patient died with septic shock.Conclusions: This case report emphasizes the severity of necrotizing fasciitis, which may occur especially in patients with predisposing factors such as diabetes mellitus and cirrhosis.