Because penicillin agents are implicated in granulopoiesis inhibition, healthcare professionals frequently consider discontinuation of such therapy in patients with decreasing white blood cell counts. No systematic review to date has described piperacillin and the patient population at risk for this adverse drug reaction (ADR). This review sought to assess the occurrence of piperacillin-induced neutropenia, describe characteristics of affected patients and assess the reporting modalities that most accurately classify this ADR. Case reports, cohort studies and clinical trials identified by comprehensive searches of PubMed and the US FDA Adverse Event Reporting System (AERS) database were reviewed for patient demographics, duration and dose of piperacillin or piperacillin-tazobactam treatment and the occurrence of neutropenia. Causality assessments were performed. Six published case reports, three cohort studies, 178 clinical trials and two compilations of phase I-III trials were reviewed. Review of case reports was notable in that the duration of beta-lactam therapy prior to the noting of leukopenia always exceeded 15 days. No deaths were recorded in this group. Among 13,816 patients enrolled in non-neutropenic fever studies, the occurrence of piperacillin-induced neutropenia was rare: five patients (0.04%) developed neutropenia; none died. The demographics for this group were poorly documented. Through the AERS database, we identified 366 unique cases of piperacillin or piperacillin-tazobactam-induced haematological abnormalities, including neutropenia (n = 183, 50.0%), leukopenia, (n = 99, 27%), agranulocytosis (n = 58, 15.8%) and others. In 62 cases, patients received between 1 and 14 days of therapy (mean 7.7 + 4.1 days). Overall, there were 82 (22.4%) deaths. Reports of haematological ADRs among patients receiving piperacillin or piperacillin-tazobactam are rare. Report of neutropenia associated with piperacillin usage prior to 15 days of therapy is a novel finding that requires further evaluation. Current reporting methods poorly characterise patient groups at risk.

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Biodiesel has been used to reduce petroleum consumption and pollutant emissions. B20, a 20% blend of biodiesel with 80% petroleum diesel, has become the most common blend used in the United States. Little quantitative information is available on the impact of biodiesel on engine operating costs and durability. In this study, eight engines and fuel systems were removed from trucks that had operated on B20 or diesel, including four 1993 Ford cargo vans and four 1996 Mack tractors (two of each running on B20 and two on diesel). The engines and fuel system components were disassembled, inspected, and evaluated to compare wear characteristics after 4 years of operation and more than 600,000 miles accumulated on B20. The vehicle case history-including mileage accumulation, fuel use, and maintenance costs-was also documented. The results indicate that there was little difference that could be attributed to fuel in operational and maintenance costs between the B20-and diesel-fueled groups. No differences in wear or other issues were noted during the engine teardown. The Mack tractors operated on B20 exhibited higher frequency of fuel filter and injector nozzle replacement. Biological contaminants may have caused the filter plugging. A sludge buildup was noted around the rocker assemblies in the Mack B20 engines. The sludge contained high levels of sodium, possibly caused by accumulation of soaps in the engine oil from out-of-specification biodiesel. The Mack and Ford engines used similar pump-line nozzle fuel injection systems, but a much larger volume of fuel was recirculated in the larger Mack engines. This, along with duty cycle and engine loading, may account for the difference in performance of the two engine types operated on B20.