Quantification of biofilm produced by clinical, environment and hands' isolates Klebsiella species using colorimetric and classical methods.

Some species of Klebsiella, such as Klebsiella pneumoniae and Klebsiella oxytoca, are important nosocomial pathogens frequently involved in outbreaks in Neonatal Intensive Care Units (NICU) and have the ability to form a biofilm. This study aims to evaluate the biofilm production of K. pneumoniae and K. oxytoca isolates collected from the hands of health professionals, neonates' blood and the environment of a Brazilian NICU, using three colorimetric methods and a classical method of counting the colony-forming units and compare the analysis among these techniques. The biofilm formation was carried out by the microplate technique, using three colorimetric assays: crystal violet, safranin and 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl) -5 [(phenylamino) arbonyl] - 2H-tetrazolium hydroxide (XTT). Also, colony-forming units were determined. Twenty-eight isolates of K. pneumoniae were collected from the blood, hands and environment and five of K. oxytoca from the hands and environment. All of them were strong biofilm producers, but K. pneumoniae isolates produced more biofilm than K. oxytoca when compared to the American Type Culture Collection (ATCC) strains used as positive controls. The number of viable cells in the biofilm produced by K. pneumoniae isolated from blood was significantly higher than in the control sample. Regarding the three colorimetric tests used in the study, the violet crystal obtained a higher absorbance average. The use of crystal-violet and XTT in the evaluation of biofilm in vitro make possible a complete analysis, since that it can quantify the total biomass (including the extracellular matrix) and evaluate the metabolic activity. In conclusion, this study identified isolates of K. pneumoniae and K. oxytoca that produce biofilms in the NICU and the bloodstream of neonates. This fact deserves attention since these patients are immunocompromised. The best methods will be chosen to answer research questions by always adopting more than one method so that more than one parameter or component of the biofilm is analyzed.

Surtos bacterianos em uma Unidade de Terapia Intensiva Neonatal: histórico de cinco anos / Bacterial outbreaks in a Neonatal Intensive Care Unit: a five-year history

Introdução: A internação em Unidade de Terapia Intensiva Neonatal (UTIN) costuma ser prolongada e os neonatos são submetidos a vários fatores de risco, possibilitando a ocorrência de surtos de tempos em tempos apesar das precauções. Objetivo: investigar a ocorrência de surtos bacterianos em uma UTIN de um hospital universitário do interior de Minas Gerais no período de janeiro de 2013 a dezembro de 2017. Métodos: os dados foram coletados a partir dos registros de surtos ocorridos em UTIN disponibilizados nos documentos do Serviço de Controle de Infecção Hospitalar do hospital, incluindo as fichas de vigilância epidemiológica "National Healthcare Safety Network" - NHSN, memorandos, resultados de exames e registros eletrônicos das descrições dos surtos. Resultados: foram encontrados quatro surtos em um período de cinco anos de estudo. O primeiro surto identificado ocorreu no ano de 2013, por infecção de corrente sanguínea pela bactéria Pantoea agglomerans e envolveu seis neonatos. O segundo ocorreu entre novembro de 2014 e março 2015 onde seis neonatos foram envolvidos e não houve um sítio predominante, sendo o Acinetobacter baumannii o micro-organismo isolado, da mesma forma que o terceiro surto, ocorrido em 2015 por esse mesmo agente, englobando 10 neonatos. O último surto aconteceu no ano de 2016 por Pseudomonas aeruginosa, sendo um surto predominantemente de colonização, onde 13 neonatos foram atingidos. Não houveram surtos no ano de 2017. Conclusão: Após levantamento epidemiológico foram identificados quatro surtos, todos por bactérias Gram-negativas. Os neonatos mais acometidos foram os prematuros e de baixo peso ao nascer. Foram identificados micro-organismos resistentes aos carbapenêmicos que, apesar de poucos, se revelaram como um problema presente no local do estudo.

Introduction: Neonatal Intensive Care Unit (NICU) hospitalization is usually prolonged, and neonates are submitted to several risk factors, allowing the occurrence of outbreaks from time to time despite precautions. Objective: To investigate the occurrence of bacterial outbreaks in an NICU of a university hospital in the interior of Minas Gerais from January 2013 to December 2017. Methods: Data were collected from the records of outbreaks occurring in NICUs available in the documents of the Hospital Infection Control Service, including the National Healthcare Safety Network - NHSN records, memos, test results, and electronic records of outbreak descriptions. Results: Four outbreaks were observed over a five-year study period. The first outbreak occurred in 2013, due to infection of the bloodstream by the species Pantoea agglomerans and involved six neonates. The second occurred between November 2014 and March 2015, where six neonates were involved and there was no predominant site, Acinetobacter B being the microorganism isolated. Similarly, the third outbreak occurred in 2015 by the same agent, comprising 10 neonates. The last outbreak occurred in 2016 by Pseudomonas aeruginosa, being a predominantly colonization outbreak, where 13 neonates were affected. There were no outbreaks in 2017. Conclusion:Four epidemiological outbreaks were identified, all of them by Gram-negative bacteria. The most affected neonates were preterm and low birth-weight infants. Microorganisms resistant to carbapenems have been identified which, although few, proved to be a problem at the study site.