Sonication as a tool for disrupting biofilms and recovering microorganisms in bladder catheters / Sonicação como uma ferramenta para romper biofilmes e recuperar microrganismos em cateteres vesicais

Abstract Introduction: Urinary catheter-related infection is commonly associated with bacterial biofilm. The impact of anaerobes is unknown, but their detection in the biofilm on this device has not been previously reported. This study aimed to evaluate the capability to recovery strict, facultative, and aerobic microorganisms in patients using bladder catheters from ICUs using conventional culture, sonication, urinary analysis, and mass spectrometry. Methods: Parallel, sonicated bladder catheters from 29 critically ill patients were compared with their routine urine culture. Identification was performed using matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry. Results: The positivity rate in urine (n = 2, 3.4%) was lower than that in sonicated catheters (n = 7, 13.8%). Conclusion: Bladder catheter sonication showed more positive culture results than urine samples for anaerobic and aerobic microorganisms. The role of anaerobes in urinary tract infection and catheter biofilm is discussed.

Resumo Introdução: A infecção relacionada ao cateter urinário é comumente associada ao biofilme bacteriano. O impacto dos anaeróbios é desconhecido, mas sua detecção no biofilme deste dispositivo não foi relatada anteriormente. Este estudo teve como objetivo avaliar a capacidade de recuperar microrganismos estritos, facultativos e aeróbios em pacientes que utilizam cateteres vesicais de UTIs utilizando cultura convencional, sonicação, análise urinária e espectrometria de massa. Métodos: Paralelamente, foram comparados cateteres vesicais sonicados de 29 pacientes gravemente enfermos com sua urocultura de rotina. A identificação foi realizada utilizando dessorção/ionização a laser assistida por matriz com espectrometria de massa por tempo de voo. Resultados: A taxa de positividade na urina (n = 2; 3,4%) foi inferior à dos cateteres sonicados (n = 7; 13,8%). Conclusão: A sonicação do cateter vesical apresentou resultados de cultura mais positivos do que as amostras de urina para microrganismos anaeróbios e aeróbios. É discutido o papel dos anaeróbios na infecção do trato urinário e no biofilme do cateter.

Detection of Microorganisms in Clinical Sonicated Orthopedic Devices Using Conventional Culture and qPCR / Detecção de microrganismos em dispositivos ortopédicos sonicados clínicos usando cultura convencional e qPCR

Abstract Objective To evaluate the sensitivity and specificity of the quantitative real-time polymerase chain reaction (qPCR) for 16S rDNA gene screening using sonicated fluid from orthopedic implants. Methods A retrospective study was conducted on 73 sonicated fluids obtained from patients with infection associated with orthopedic implants. The samples were subjected to conventional culture and molecular testing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and qPCR for 16S rDNA. The cycle threshold values were used to define a cut-off of the qPCR of the 16S rDNA for negative and positive cultures. Results No statistical differences were observed between the positive and negative culture groups based on the time from the first surgery to infection (p= 0.958), age (p =0.269), or general comorbidities. Nevertheless, a statistical difference was found between the mean duration of antibiotic use before device removal (3.41 versus 0.94; p =0.016). Bacterial DNA was identified in every sample from the sonicated fluids. The median cycle thresholds of the positive and negative cultures were of 25.6 and 27.3 respectively (p< 0.001). As a diagnostic tool, a cycle threshold cut-off of 26.89 demonstrated an area under the curve of the receiver operating characteristic of 0.877 (p≤ 0.001). Conclusion The presence of antimicrobial agents for more than 72 hours decreased culture positivity, but did not influence the qPCR results. Despite this, amplification of the 16S rDNA may overestimate infection diagnosis.

Resumo Objetivo Avaliar a sensibilidade e a especificidade da reação em cadeia de polimerase em tempo real quantitativa (quantitative real-time polymerase chain reaction, qPCR, em inglês) para a triagem do gene rDNA 16S, com a utilização do fluido sonicado de implantes ortopédicos. Métodos Um estudo retrospectivo foi realizado em 73 fluidos sonicados obtidos de pacientes com infecção associada aos implantes ortopédicos. As amostras foram submetidas a cultura convencional e a teste molecular utilizando ionização e dessorção a laser assistida por matriz com espectrometria de massa por tempo de voo (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF MS, em inglês) e qPCR para o gene rDNA 16S. Os valores limiares do ciclo foram usados para definir um ponto de corte para a qPCR do gene rDNA 16S para culturas negativas e positivas. Resultados Não foram observadas diferenças estatísticas entre os grupos de cultura positiva e negativa com base no tempo desde a primeira cirurgia até a infecção (p= 0,958), na idade (p= 0,269), ou nas comorbidades em geral. No entanto, uma diferença estatística foi encontrada entre a duração média do uso de antibióticos antes da remoção do dispositivo (3,41 versus 0,94; p= 0,016). O DNA bacteriano foi identificado em todas as amostras dos fluidos sonicados. Os limiares do ciclo médio de culturas positivas e negativas foram de 25,6 e 27,3, respectivamente (p< 0,001). Como uma ferramenta de diagnóstico, um corte do limite do ciclo de 26,89 demonstrou uma área sob a curva da característica de operação do receptor de 0,877 (p ≤ 0,001). Conclusão A presença de agentes antimicrobianos por mais de 72 horas diminuiu a positividade da cultura, mas não influenciou os resultados da qPCR. Apesar disso, a amplificação do rDNA 16S pode sobrestimar o diagnóstico de infecção.

Comparison of intermittent versus continuous-infusion vancomycin for treating severe patients in intensive care units

Abstract Purpose The aim of this study was to compare pharmacokinetic characteristics between intermittent infusion and continuous infusion of vancomycin for critically ill patients admitted to intensive care units. Methods Intermittent therapy was administered for 60 minutes and prescribed as a loading dose of 30 mg/kg and continued with 15 mg/kg q12 h. Continuous infusion was prescribed as a loading dose of 30 mg/kg followed by 30 mg/kg on constant infusion pump. Blood samples from vancomycin intermittent infusion group were collected 1 h before third dose, 1 h, 8 h and 24 h after third dose infusion. Blood samples from vancomycin continuous infusion group were collected 1 h after loading dose, 12 h, 24 h, 36 h, and 48 h after continuous infusion initiation. Results Median serum concentration of continuous infusion group at 24-hour was 23.59 µg/mL [14.52-28.97], while of intermittent infusion group at 23-hour was 12.30 µg/mL [7.27-18.12] and on 25-hour was 17.58 µg/mL [12.5-22.5]. Medians AUC24-48h were 357.2 mg.h/L and 530.2 mg.h/L for intermittent infusion and continuous infusion groups, respectively (p = 0.559). Conclusion Vancomycin CI reached steady state earlier, which guaranteed therapeutic levels from the first day and made it possible to manage therapeutic drug monitoring faster.

Daptomycin to bone and joint infections and prosthesis joint infections: a systematic review

ABSTRACT Backgroud: Daptomycin has been used in bone and joint infections (BJI) and prosthesis joint infections (PJI) considering spectrum of activity and biofilm penetration. However, the current experience is based on case reports, case series, cohorts, and international surveys. The aim of this systematic review was to evaluate studies about daptomycin treatment efficacy in BJI/PJI compared to other antibiotic regimens. Methods: PubMed, LILACS, Scielo and Web of Science databases were searched for articles about daptomycin and treatment of BJI and PJI from inception to March 2018. Inclusion criteria were any published researches that included patients with BJI treated with daptomycin. Diagnosis of BJI was based on clinical, laboratory and radiological findings according to IDSA guidelines. Results: From 5107 articles, 12 articles were included. Only three studies described the outcomes of patients with BJI treated with daptomycin with comparator regimen (vancomycin, teicoplanin and oxacillin). Studies presented large heterogeneity regarding device related infections, surgical procedures, and daptomycin regimens (varied from 4 mg/kg to 10 mg/kg). A total of 299 patients have been included in all studies (184 infections associated with orthopedic disposal and 115 osteomyelitis/septic arthritis). Two hundred and thirty-three patients were treated with daptomycin. The clinical cure rates on device related and non-device related infections (i.e. osteomyelitis) were 70% and 78%, respectively. Compared to all regimens evaluated, daptomycin group outcomes were non-inferior. Conclusion: Although a randomized clinical trial is needed, this systematic review tends to support daptomycin usage for bone and joint infections.