Class of 2011 Abstract / OBJECTIVES: The objective of this study was to compare patient clinical outcomes, vascular access line administration complications, and piperacillin-tazobactam costs before and after implementation of an extended infusion piperacillin-tazobactam protocol in adult patients at an academic medical center. METHODS: In this IRB-approved retrospective project, the effect of the implementation of a piperacillin- tazobactam extended infusion protocol at a tertiary care, academic medical center was accessed. The use of piperacillin-tazobactam was accessed during 3 one-month time periods in 2010: Time Period 1 (pre-education and implementation of protocol), Time Period 2 (post-education of pharmacists and infectious disease physicians), and Time Period 3 (post-education of healthcare professionals and implementation of extended-infusion piperacillin- tazobactam protocol). Patients were excluded if piperacillin-tazobactam therapy was prescribed for less than 72 hours. Data collected in each one-month period included demographic data, culture results, number of piperacillin-tazobactam grams prescribed per day, percentage of patients who received extended-infusion piperacillin-tazobactam, other antimicrobial therapy prescribed, medications prescribed with intravenous incompatibilities with piperacillin-tazobactam, number of intravenous line lumens before and after start of piperacillin-tazobactam therapy, length of stay, and all-cause 30 day mortality. RESULTS: During a three step process, the use of extended infusion piperacillin-tazobactam was implemented at an academic medical center after administration approval, education of healthcare professionals, and development of an electronic piperacillin-tazobactam order set. Use of extended-infusion piperacillin-tazobactam protocol significantly decreased the average daily piperacillin-tazobactam dose per patient. CONCLUSION: Implementation of extended-infusion piperacillin-tazobactam protocol for adult patients did significantly decrease the average daily dose of piperacillin-tazobactam per patient (reduced drug cost) but increased vascular access requirements.

Pulmonary infections in critically ill patients are common, frequently lethal and treatment may be complicated by bacterial resistance. Piperacillin-tazobactam (PTZ) is a broad-spectrum β-lactam antibiotic, frequently used for pulmonary infections. Lung antibiotic concentration reflects target site concentrations in patients with pneumonia. Critically ill patient’s exhibit marked pharmacokinetic (PK) variability. PTZ exposures resulting in maximal bacterial killing and prevention of emergence of drug resistance are not known. Administration of PTZ by extended infusions (EI) or using Bayesian dosage optimisation, instead of a fixed bolus regimen, may improve clinical outcomes. Experimental work was conducted in an in vitro hollow fibre infection model (HFIM) using two densities of Pseudomonas aeruginosa. Experimental data was described by a mathematical model allowing identification of PTZ exposures associated with bacterial killing and suppression of the emergence of resistance. The population PK of PTZ in the plasma and lung of 17 critically ill patients was estimated. Monte Carlo simulation was used to explore the proportion of patients that achieve the plasma and lung PTZ exposures associated with bacterial killing and resistance suppression and to determine the effect of administration schedule. Finally, the population PK of PTZ in the plasma of 146 critically ill patients was estimated and used to construct computer software that can individualise PTZ dosing. Precision of the dosing software was assessed in 8 additional individuals. At low bacterial density a trough piperacillin:MIC ratio of 3.4 for bolus and 10.4 for EI regimens were able to suppress the emergence of resistance. At higher bacterial density all regimens were associated with growth of a resistant sub-population. Pulmonary piperacillin and tazobactam concentrations were unpredictable and negatively correlated to pulmonary permeability. Simulations revealed that EI, compared with bolus dosing, of PTZ is associated with a higher likelihood of bacteria killing. Similar probability of developing resistance was predicted with PTZ administration by EI and by bolus administration. Performance of the dose optimisation software was satisfactory. Current PTZ regimens are insufficient to treat pneumonia in approximately 14% of critically ill patients. Delivery of PTZ by EI may be a more effective method of administration for some patients with nosocomial infections. Individualised PTZ regimens, delivering a target piperacillin concentration, identified in a HFIM, are achievable and should improved clinical outcomes. Patients with a high bacterial burden may required alternative therapeutic strategies to maximize bacterial killing and prevent antimicrobial resistance.

Obligat anaerob wachsende Bakterien sind an einer Vielzahl von Infektionen beteiligt. Dabei ist Bacteroides fragilis einer der wichtigsten opportunistischen Erreger unter den Anaerobiern. Bei Verdacht auf eine Infektion durch obligate Anaerobier muss nach Materialentnahme für die mikrobiologische Diagnostik unverzüglich eine kalkulierte Therapie eingeleitet werden. Oft ist eine chirurgische Therapie notwendig, die ebenso wie eine adäquate Antibiotikatherapie entscheidend für den Verlauf der Erkrankung ist. Wichtige Substanzen für eine Therapie bei Infektionen mit Beteiligung von B. fragilis sind Clindamycin, Imipenem, Metronidazol und Piperacillin/Tazobactam. Um Aussagen zur in vitro Wirksamkeit dieser Antibiotika gegenüber obligaten Anaerobiern treffen zu können, wurden in der vorliegenden Arbeit die Aktivitäten von verschiedenen Konzentrationen des jeweiligen Antibiotikums auf das Wachstum von sensiblen und resistenten B. fragilis Stämmen mittels Absterbekinetik untersucht. In Abhängigkeit von der zuvor ermittelten minimalen Hemmkonzentration des jeweiligen Antibiotikums wurden die Stämme in 2 Gruppen eingeteilt. Die erste Gruppe umfasst alle Stämme mit einer MHK ≤ 8 µg/ml. In der zweiten Gruppe sind die Stämme mit einer MHK > 8 µg/ml zusammengefasst. Die einzelnen Stämme wurden mit einem Vielfachen der minimalen Hemmkonzentration (MHK) beziehungsweise einem Vielfachen der im menschlichen Blutplasma maximal erreichbaren Konzentration (Cmax) des jeweiligen Antibiotikums inkubiert und die Bakterienkonzentration zu definierten Zeitpunkten ermittelt. Dadurch können sowohl die Wirksamkeit unterschiedlicher Antibiotikakonzentrationen als auch verschiedene Antibiotikaklassen miteinander verglichen und Aussagen zu Empfehlungen für kalkulierte Therapien getroffen werden.

Obligat anaerob wachsende Bakterien sind an einer Vielzahl von Infektionen beteiligt. Dabei ist Bacteroides fragilis einer der wichtigsten opportunistischen Erreger unter den Anaerobiern. Bei Verdacht auf eine Infektion durch obligate Anaerobier muss nach Materialentnahme für die mikrobiologische Diagnostik unverzüglich eine kalkulierte Therapie eingeleitet werden. Oft ist eine chirurgische Therapie notwendig, die ebenso wie eine adäquate Antibiotikatherapie entscheidend für den Verlauf der Erkrankung ist. Wichtige Substanzen für eine Therapie bei Infektionen mit Beteiligung von B. fragilis sind Clindamycin, Imipenem, Metronidazol und Piperacillin/Tazobactam. Um Aussagen zur in vitro Wirksamkeit dieser Antibiotika gegenüber obligaten Anaerobiern treffen zu können, wurden in der vorliegenden Arbeit die Aktivitäten von verschiedenen Konzentrationen des jeweiligen Antibiotikums auf das Wachstum von sensiblen und resistenten B. fragilis Stämmen mittels Absterbekinetik untersucht. In Abhängigkeit von der zuvor ermittelten minimalen Hemmkonzentration des jeweiligen Antibiotikums wurden die Stämme in 2 Gruppen eingeteilt. Die erste Gruppe umfasst alle Stämme mit einer MHK ≤ 8 µg/ml. In der zweiten Gruppe sind die Stämme mit einer MHK > 8 µg/ml zusammengefasst. Die einzelnen Stämme wurden mit einem Vielfachen der minimalen Hemmkonzentration (MHK) beziehungsweise einem Vielfachen der im menschlichen Blutplasma maximal erreichbaren Konzentration (Cmax) des jeweiligen Antibiotikums inkubiert und die Bakterienkonzentration zu definierten Zeitpunkten ermittelt. Dadurch können sowohl die Wirksamkeit unterschiedlicher Antibiotikakonzentrationen als auch verschiedene Antibiotikaklassen miteinander verglichen und Aussagen zu Empfehlungen für kalkulierte Therapien getroffen werden.

Infections in critically ill patients are a problem for the healthcare system and at any one time, 70 % of all intensive care unit (ICU) patients are treated with antibiotics. Antibiotics bind toproteins in the blood, but only unbound drug can diffuse over capillary membranes and bindto the targeted receptor. Standard protein binding percentages for antibiotics have been developed from studies on healthy volunteers and dosing regimens for patients are adapted accordingly. The determination of the total concentration of antibiotics in patients’ bloodsamples is, based on the standard percentages, ordinarily representative for the pharmacological effect of the antibiotic. However, certain conditions that are common incritically ill patients can alter protein binding percentages, resulting in a larger or smaller unbound fraction. This in turn can result in toxicity or therapeutic failure. The aim of this project was to develop an analytical method for the determination of the unbound concentration of the Beta-Lactam antibiotics cefotaxime, flucloxacillin, cloxacillin and piperacillin in plasma. A method was successfully developed using ultrafiltration for the extraction of unbound analytes and ultra high performance liquid chromatography tandem mass spectrometry, UHPLC-MS/MS, for their quantification. The method was partly validated according to the European Medicines Agency’s guidelines on bioanalytical method validation. / Kritiskt sjuka patienter med infektioner är en börda för sjukvården och 70 % av alla patienter på intensivvårdsavdelningar är ordinerade antibiotika. Antibiotika binder till proteiner i blodet, men enbart den icke-proteinbundna (fria) fraktionen kan diffundera över kapillära membran och binda till receptorer. Standardproteinbindningsgrad för olika antibiotika har utvecklats från studier på friska frivilliga och doseringen av läkemedlen är anpassade därefter. Den totala koncentrationen av antibiotika i patienters blod är vanligen representativ för den farmakologiska effekten. Dock kan vissa sjukdomar påverka proteinbindningsgraden vilket resulterar i en större eller mindre mängd fria antibiotika i blodcirkulationen. Det här kan i sintur resultera i toxicitet eller otillräcklig effekt av läkemedlet. Syftet med det här projektet var att utveckla en analytisk metod för att bestämma den fria koncentrationen av Beta-Lactam antibiotikan cefotaxim, flukloxacillin, kloxacillin och piperacillin i plasma. En metod utvecklades med ultrafiltrering för extraktion av den fria fraktionen och högupplösande vätskekromatografi och tandem masspektrometri, UHPLCMS/MS, för kvantifiering av analyterna. Metoden validerades delvis enligt den Europeiska Läkemedelsmyndighetens riktlinjer för bioanalytisk metodvalidering.

Empiric antimicrobial therapy often consists of the combination of Gram-positive coverage with vancomycin (VAN) and Gram-negative coverage, specifically an anti-pseudomonal beta-lactam, such as piperacillin-tazobactam (PTZ). Nephrotoxicity is commonly associated with VAN therapy; however, recent reports demonstrate increasing nephrotoxicity rates among patients treated with the combination of VAN and PTZ. This study evaluated the effect of the VAN/PTZ combination on acute kidney injury (AKI), as defined by the RIFLE criteria, compared to VAN and PTZ monotherapies. Overall, 11,650 patients were analyzed, with 1,647 (14.1%) AKI cases occurring. AKI was significantly more frequent in the VAN/PTZ group (21%) compared to either monotherapy group (VAN 8.3%, PTZ 7.8%, p<0.001 for both). Combination therapy was independently associated with higher AKI odds compared to monotherapy with either agent (aOR=2.03; 95% CI 1.74-2.39; aOR=2.31; 95% CI 1.97-2.71, for VAN and PTZ, respectively). Receipt of concomitant nephrotoxic drugs were independently associated with increased AKI rates, as were increased duration of therapy, length of hospital stay, increasing severity of illness, and increasing baseline renal function. VAN combined with PTZ was associated with twice the odds of AKI development compared to either agent as monotherapy. This demonstrates the need for judicious use of combination empiric therapy.

O Platelia® Aspergillus EIA é um teste de ELISA sanduíche para diagnóstico precoce de aspergilose em pacientes neutropênicos que se baseia na detecção de um antígeno (galactomanana) da parede celular de Aspergillus spp. O trabalho objetivou avaliar a eficácia deste teste em outros hospedeiros suscetíveis à aspergilose e ainda, avaliar a interferência de potenciais falso-positivos no Platelia® Aspergillus EIA, como outras micoses sistêmicas e um antimicrobiano produzido a partir de fungos (piperacilina-tazobactam). Quatro experimentos foram realizados para contemplar os objetivos propostos. Amostras de lavado broncoalveolar de 60 pacientes transplantados de pulmão provenientes da Santa-Casa Complexo Hospitalar de Porto Alegre foram colhidas durante um período de aproximadamente 2 anos e testadas para detecção de galactomanana. Os pacientes foram classificados em aspergilose comprovada, provável e possível, colonização ou exame de vigilância de acordo com critérios do EORTC. Utilizando os casos comprovados (5) e prováveis (6) como positivos, foi calculada a curva ROC que demonstrou valores de sensibilidade de 90,9% e especificidade de 90,6% em um ponto de corte de 1,5. A eficácia do Platelia® Aspergillus EIA foi avaliada também em pingüins em cativeiro. Soros de 35 animais foram incluídos no estudo, 9 com aspergilose, 3 com malária, 2 com caquexia e 21 saudáveis. Os soros foram testados por imunodifusão dupla e ELISA sanduíche, resultando em valores de sensibilidade de 33% e 100% e especificidade de 96% e 0, respectivamente. A reação cruzada de outras micoses sistêmicas no Platelia® Aspergillus EIA foi avaliada a partir de 120 amostras de soro de pacientes com paracoccidioidomicose, histoplasmose, criptococose por Cryptococcus neoformans e criptococose por C. gattii. Todas as micoses foram responsáveis por resultados falso-positivos no ELISA sanduíche, sendo de 50%, 67%, 66% e 36,6% a taxa de positividade de cada micose, respectivamente. Em adição, 5 lotes de piperacilina-tazobactam foram testados em concentração de uso clínico (45mg/ml) para avaliação de interferência no Platelia® Aspergillus EIA. Destas, apenas uma resultou em valores maiores do que o ponto de corte (0,5), sendo submetida a sucessivas diluições até mimetizar concentrações plasmáticas do fármaco alcançáveis no soro humano, as quais resultaram em valores menores que 0,5, sendo consideradas negativas. Concluindo, utilizando um ponto de corte maior do que indicado pelo fabricante para uso em neutropênicos, a eficácia do teste foi comprovada para utilização em amostras de lavado broncoalveolar de pacientes transplantados de pulmão. Por outro lado, no hospedeiro animal testado, pingüins, o teste apresentou especificidade nula, não possuindo aplicabilidade como ferramenta diagnóstica para aspergilose neste grupo. Quanto aos fatores de interferência no Platelia® Aspergillus EIA avaliados, a alta taxa de resultados falso-positivos referentes à infecção por outras micoses sistêmicas reflete na necessidade de interpretar um teste positivo dentro do contexto epidemiológico do paciente. Por outro lado, as piperacilinas-tazobactam disponíveis no mercado brasileiro não interferiram no resultado do Platelia® Aspergillus EIA. No entanto como a variabilidade de galactomanana existe entre lotes, ainda é aconselhável que as amostras para realização do ELISA sanduíche sejam colhidas antes da próxima administração do fármaco. / Platelia® Aspergillus EIA is a sandwich ELISA to the diagnostic of aspergillosis in neutropenic patients. It detects an antigen (galactomannan) from Aspergillus cell wall. Here it was evaluated the performance of this test in other susceptible hosts and the interference of potentials false-positives factors in Platelia® Aspergillus EIA. Systemic mycosis and an antimicrobial produced from molds (piperacillin-tazobactam) were tested. Four experiments were executed to study conduce. Bronchoalveolar samples from 60 lung transplant recipients from Santa Casa-Complexo Hospitalar de Porto Alegre were collected during almost two years and tested for galactomannan detection. Patients were classified in proven, probable or possible aspergillosis according to EORTC criteria, or in colonization or surveillance. Considering proven (5) and probable (6) as true positive cases, ROC curve was calculated and showed 90.9% of sensitivity and 90.6% of specificity with 1.5 as optimal cutoff. Platelia® Aspergillus EIA efficacy was also tested in captive penguins. Sera from 35 animals were included in the study, 9 with aspergillosis, 3 with malaria, 2 with cachexia and 21 healthy. Samples were tested by double immunodiffusion and sandwich ELISA, resulting in sensitivity values of 33% and 100% and specificity of 96% and 0, respectively. Cross reaction in Platelia® Aspergillus EIA was evaluated with 120 serum samples of patients with paracocciddioidomicosis, histoplasmosis, criptococosis due to Cryptococcus neoformans and criptococosis due to C. gattii. False-positive results were observed in all mycosis, with rates of 50%, 67%, 66% and 36,6%, respectively. In addition, 5 piperacillin-tazobactam batches were tested, in a concentration of clinical use (45mg/ml), to evaluate it interference in Platelia® Aspergillus EIA. Those, only one showed positive value, and had been retest after serial dilutions until plasmatic concentration, resulting in value lower than 0.5, negative. In conclusion, with a higher cut-off than the indicated from the manufacturer, the efficacy of bronchoalveolar samples tested in Platelia® Aspergillus EIA for the diagnostic of aspergillosis in lung transplant recipients was proved. Controversially, in penguins, the test specificity was zero, showing non applicability as a diagnostic method for aspergillosis in this group of risk. Interference in Platelia® Aspergillus EIA due to other systemic mycoses shows the necessity to interpret a positive result after the evaluation of patient epidemiologic context. Finally, piperacillin-tazobactam available in the Brazilian market did not correspond to false-positive results in Platelia® Aspergillus EIA. However, given that variability occurs between distinct batches, still is indicating to collect samples for galactomannan detection before the next administration of the drug.

Acute kidney injury (AKI) is a significant adverse effect of many medications that leads to increased morbidity, cost, and mortality among hospitalized patients. Recent literature supports a strong link between empiric combination antimicrobial therapy and increased AKI risk. As briefly summarized below, the following chapters describe my research conducted in this area. Chapter 1 presents and summarizes the published literature connecting combination antimicrobial therapy with increased AKI incidence. This chapter sets the specific aims I aim to achieve during my dissertation project. Chapter 2 describes a study in which patients receiving vancomycin (VAN) in combination with piperacillin-tazobactam (TZP) or cefepime (CFP). I matched over 1,600 patients receiving both combinations and found a significantly lower incidence of AKI among patient receiving the CFP+VAN combination when controlling for confounders. The conclusion of this study is that VAN+TZP has significantly increased risk of AKI compared to CFP+VAN, confirming the results of previous literature. Chapter 3 presents a study of patients receiving VAN in combination with meropenem (MEM) or TZP. This study included over 10,000 patients and used inverse probability of treatment weighting to conserve data for this population. After controlling for confounders, VAN+TZP was associated with significantly more AKI than VAN+MEM. This study demonstrates that MEM is clinically viable alternative to TZP in empiric antimicrobial therapy. Chapter 4 describes a study in which patients receiving TZP or ampicillin-sulbactam (SAM) with or without VAN were analyzed for AKI incidence. The purpose of this study was to identify whether the addition of a beta-lactamase inhibitor to a beta-lactam increased the risk of AKI. This study included more than 2,400 patients receiving either agent and found that there were no differences in AKI among patients receiving SAM or TZP; however, AKI was significantly more common in the TZP group when stratified by VAN exposure. This study shows that comparisons of TZP to other beta-lactams without beta-lactamase inhibitors are valid. Chapter 5 presents a study of almost 30,000 patients who received combination antimicrobial therapy over an 8-year period. This study demonstrates similar AKI incidence to previous literature and the studies presented in the previous chapters. Additionally, the results of the predictive models suggest that further work in this research area is needed. The studies conducted present a clear message that patients receiving VAN+TZP are at significantly greater risk of AKI than alternative regimens for empiric coverage of infection.

O Platelia® Aspergillus EIA é um teste de ELISA sanduíche para diagnóstico precoce de aspergilose em pacientes neutropênicos que se baseia na detecção de um antígeno (galactomanana) da parede celular de Aspergillus spp. O trabalho objetivou avaliar a eficácia deste teste em outros hospedeiros suscetíveis à aspergilose e ainda, avaliar a interferência de potenciais falso-positivos no Platelia® Aspergillus EIA, como outras micoses sistêmicas e um antimicrobiano produzido a partir de fungos (piperacilina-tazobactam). Quatro experimentos foram realizados para contemplar os objetivos propostos. Amostras de lavado broncoalveolar de 60 pacientes transplantados de pulmão provenientes da Santa-Casa Complexo Hospitalar de Porto Alegre foram colhidas durante um período de aproximadamente 2 anos e testadas para detecção de galactomanana. Os pacientes foram classificados em aspergilose comprovada, provável e possível, colonização ou exame de vigilância de acordo com critérios do EORTC. Utilizando os casos comprovados (5) e prováveis (6) como positivos, foi calculada a curva ROC que demonstrou valores de sensibilidade de 90,9% e especificidade de 90,6% em um ponto de corte de 1,5. A eficácia do Platelia® Aspergillus EIA foi avaliada também em pingüins em cativeiro. Soros de 35 animais foram incluídos no estudo, 9 com aspergilose, 3 com malária, 2 com caquexia e 21 saudáveis. Os soros foram testados por imunodifusão dupla e ELISA sanduíche, resultando em valores de sensibilidade de 33% e 100% e especificidade de 96% e 0, respectivamente. A reação cruzada de outras micoses sistêmicas no Platelia® Aspergillus EIA foi avaliada a partir de 120 amostras de soro de pacientes com paracoccidioidomicose, histoplasmose, criptococose por Cryptococcus neoformans e criptococose por C. gattii. Todas as micoses foram responsáveis por resultados falso-positivos no ELISA sanduíche, sendo de 50%, 67%, 66% e 36,6% a taxa de positividade de cada micose, respectivamente. Em adição, 5 lotes de piperacilina-tazobactam foram testados em concentração de uso clínico (45mg/ml) para avaliação de interferência no Platelia® Aspergillus EIA. Destas, apenas uma resultou em valores maiores do que o ponto de corte (0,5), sendo submetida a sucessivas diluições até mimetizar concentrações plasmáticas do fármaco alcançáveis no soro humano, as quais resultaram em valores menores que 0,5, sendo consideradas negativas. Concluindo, utilizando um ponto de corte maior do que indicado pelo fabricante para uso em neutropênicos, a eficácia do teste foi comprovada para utilização em amostras de lavado broncoalveolar de pacientes transplantados de pulmão. Por outro lado, no hospedeiro animal testado, pingüins, o teste apresentou especificidade nula, não possuindo aplicabilidade como ferramenta diagnóstica para aspergilose neste grupo. Quanto aos fatores de interferência no Platelia® Aspergillus EIA avaliados, a alta taxa de resultados falso-positivos referentes à infecção por outras micoses sistêmicas reflete na necessidade de interpretar um teste positivo dentro do contexto epidemiológico do paciente. Por outro lado, as piperacilinas-tazobactam disponíveis no mercado brasileiro não interferiram no resultado do Platelia® Aspergillus EIA. No entanto como a variabilidade de galactomanana existe entre lotes, ainda é aconselhável que as amostras para realização do ELISA sanduíche sejam colhidas antes da próxima administração do fármaco. / Platelia® Aspergillus EIA is a sandwich ELISA to the diagnostic of aspergillosis in neutropenic patients. It detects an antigen (galactomannan) from Aspergillus cell wall. Here it was evaluated the performance of this test in other susceptible hosts and the interference of potentials false-positives factors in Platelia® Aspergillus EIA. Systemic mycosis and an antimicrobial produced from molds (piperacillin-tazobactam) were tested. Four experiments were executed to study conduce. Bronchoalveolar samples from 60 lung transplant recipients from Santa Casa-Complexo Hospitalar de Porto Alegre were collected during almost two years and tested for galactomannan detection. Patients were classified in proven, probable or possible aspergillosis according to EORTC criteria, or in colonization or surveillance. Considering proven (5) and probable (6) as true positive cases, ROC curve was calculated and showed 90.9% of sensitivity and 90.6% of specificity with 1.5 as optimal cutoff. Platelia® Aspergillus EIA efficacy was also tested in captive penguins. Sera from 35 animals were included in the study, 9 with aspergillosis, 3 with malaria, 2 with cachexia and 21 healthy. Samples were tested by double immunodiffusion and sandwich ELISA, resulting in sensitivity values of 33% and 100% and specificity of 96% and 0, respectively. Cross reaction in Platelia® Aspergillus EIA was evaluated with 120 serum samples of patients with paracocciddioidomicosis, histoplasmosis, criptococosis due to Cryptococcus neoformans and criptococosis due to C. gattii. False-positive results were observed in all mycosis, with rates of 50%, 67%, 66% and 36,6%, respectively. In addition, 5 piperacillin-tazobactam batches were tested, in a concentration of clinical use (45mg/ml), to evaluate it interference in Platelia® Aspergillus EIA. Those, only one showed positive value, and had been retest after serial dilutions until plasmatic concentration, resulting in value lower than 0.5, negative. In conclusion, with a higher cut-off than the indicated from the manufacturer, the efficacy of bronchoalveolar samples tested in Platelia® Aspergillus EIA for the diagnostic of aspergillosis in lung transplant recipients was proved. Controversially, in penguins, the test specificity was zero, showing non applicability as a diagnostic method for aspergillosis in this group of risk. Interference in Platelia® Aspergillus EIA due to other systemic mycoses shows the necessity to interpret a positive result after the evaluation of patient epidemiologic context. Finally, piperacillin-tazobactam available in the Brazilian market did not correspond to false-positive results in Platelia® Aspergillus EIA. However, given that variability occurs between distinct batches, still is indicating to collect samples for galactomannan detection before the next administration of the drug.

O Platelia® Aspergillus EIA é um teste de ELISA sanduíche para diagnóstico precoce de aspergilose em pacientes neutropênicos que se baseia na detecção de um antígeno (galactomanana) da parede celular de Aspergillus spp. O trabalho objetivou avaliar a eficácia deste teste em outros hospedeiros suscetíveis à aspergilose e ainda, avaliar a interferência de potenciais falso-positivos no Platelia® Aspergillus EIA, como outras micoses sistêmicas e um antimicrobiano produzido a partir de fungos (piperacilina-tazobactam). Quatro experimentos foram realizados para contemplar os objetivos propostos. Amostras de lavado broncoalveolar de 60 pacientes transplantados de pulmão provenientes da Santa-Casa Complexo Hospitalar de Porto Alegre foram colhidas durante um período de aproximadamente 2 anos e testadas para detecção de galactomanana. Os pacientes foram classificados em aspergilose comprovada, provável e possível, colonização ou exame de vigilância de acordo com critérios do EORTC. Utilizando os casos comprovados (5) e prováveis (6) como positivos, foi calculada a curva ROC que demonstrou valores de sensibilidade de 90,9% e especificidade de 90,6% em um ponto de corte de 1,5. A eficácia do Platelia® Aspergillus EIA foi avaliada também em pingüins em cativeiro. Soros de 35 animais foram incluídos no estudo, 9 com aspergilose, 3 com malária, 2 com caquexia e 21 saudáveis. Os soros foram testados por imunodifusão dupla e ELISA sanduíche, resultando em valores de sensibilidade de 33% e 100% e especificidade de 96% e 0, respectivamente. A reação cruzada de outras micoses sistêmicas no Platelia® Aspergillus EIA foi avaliada a partir de 120 amostras de soro de pacientes com paracoccidioidomicose, histoplasmose, criptococose por Cryptococcus neoformans e criptococose por C. gattii. Todas as micoses foram responsáveis por resultados falso-positivos no ELISA sanduíche, sendo de 50%, 67%, 66% e 36,6% a taxa de positividade de cada micose, respectivamente. Em adição, 5 lotes de piperacilina-tazobactam foram testados em concentração de uso clínico (45mg/ml) para avaliação de interferência no Platelia® Aspergillus EIA. Destas, apenas uma resultou em valores maiores do que o ponto de corte (0,5), sendo submetida a sucessivas diluições até mimetizar concentrações plasmáticas do fármaco alcançáveis no soro humano, as quais resultaram em valores menores que 0,5, sendo consideradas negativas. Concluindo, utilizando um ponto de corte maior do que indicado pelo fabricante para uso em neutropênicos, a eficácia do teste foi comprovada para utilização em amostras de lavado broncoalveolar de pacientes transplantados de pulmão. Por outro lado, no hospedeiro animal testado, pingüins, o teste apresentou especificidade nula, não possuindo aplicabilidade como ferramenta diagnóstica para aspergilose neste grupo. Quanto aos fatores de interferência no Platelia® Aspergillus EIA avaliados, a alta taxa de resultados falso-positivos referentes à infecção por outras micoses sistêmicas reflete na necessidade de interpretar um teste positivo dentro do contexto epidemiológico do paciente. Por outro lado, as piperacilinas-tazobactam disponíveis no mercado brasileiro não interferiram no resultado do Platelia® Aspergillus EIA. No entanto como a variabilidade de galactomanana existe entre lotes, ainda é aconselhável que as amostras para realização do ELISA sanduíche sejam colhidas antes da próxima administração do fármaco. / Platelia® Aspergillus EIA is a sandwich ELISA to the diagnostic of aspergillosis in neutropenic patients. It detects an antigen (galactomannan) from Aspergillus cell wall. Here it was evaluated the performance of this test in other susceptible hosts and the interference of potentials false-positives factors in Platelia® Aspergillus EIA. Systemic mycosis and an antimicrobial produced from molds (piperacillin-tazobactam) were tested. Four experiments were executed to study conduce. Bronchoalveolar samples from 60 lung transplant recipients from Santa Casa-Complexo Hospitalar de Porto Alegre were collected during almost two years and tested for galactomannan detection. Patients were classified in proven, probable or possible aspergillosis according to EORTC criteria, or in colonization or surveillance. Considering proven (5) and probable (6) as true positive cases, ROC curve was calculated and showed 90.9% of sensitivity and 90.6% of specificity with 1.5 as optimal cutoff. Platelia® Aspergillus EIA efficacy was also tested in captive penguins. Sera from 35 animals were included in the study, 9 with aspergillosis, 3 with malaria, 2 with cachexia and 21 healthy. Samples were tested by double immunodiffusion and sandwich ELISA, resulting in sensitivity values of 33% and 100% and specificity of 96% and 0, respectively. Cross reaction in Platelia® Aspergillus EIA was evaluated with 120 serum samples of patients with paracocciddioidomicosis, histoplasmosis, criptococosis due to Cryptococcus neoformans and criptococosis due to C. gattii. False-positive results were observed in all mycosis, with rates of 50%, 67%, 66% and 36,6%, respectively. In addition, 5 piperacillin-tazobactam batches were tested, in a concentration of clinical use (45mg/ml), to evaluate it interference in Platelia® Aspergillus EIA. Those, only one showed positive value, and had been retest after serial dilutions until plasmatic concentration, resulting in value lower than 0.5, negative. In conclusion, with a higher cut-off than the indicated from the manufacturer, the efficacy of bronchoalveolar samples tested in Platelia® Aspergillus EIA for the diagnostic of aspergillosis in lung transplant recipients was proved. Controversially, in penguins, the test specificity was zero, showing non applicability as a diagnostic method for aspergillosis in this group of risk. Interference in Platelia® Aspergillus EIA due to other systemic mycoses shows the necessity to interpret a positive result after the evaluation of patient epidemiologic context. Finally, piperacillin-tazobactam available in the Brazilian market did not correspond to false-positive results in Platelia® Aspergillus EIA. However, given that variability occurs between distinct batches, still is indicating to collect samples for galactomannan detection before the next administration of the drug.