Actinomycosis with Fusobacterium empyema.

Actinomyces, are gram-positive, non-spore forming anaerobic or microaerophilic species. Empyema due to actinomycosis is relatively rare and can be difficult to diagnose as the presenting symptoms may be indolent and the micro-organism may be difficult to culture. This case report describes a patient presenting with dyspnoea, weight loss and lethargy. The chest radiograph, CT and thoracic ultrasound revealed a left-sided pleural effusion. A chest drain was inserted under ultrasound guidance. The pleural fluid was macroscopically consistent with pus and microbiology showed growth of gram-positive bacilli, Actinomyces meyeri as well as the Fusobacterium species. The patient was treated with a drainage of the pleural fluid, a prolonged course of antibiotics and made a good recovery. The awareness that the Actinomyces species and the Fusobacterium species through their synergistic interaction may cause empyema, may lead to a timely diagnosis and treatment.

High-throughput mass-directed parallel purification incorporating a multiplexed single quadrupole mass spectrometer.

We report on the development of a parallel HPLC/MS purification system incorporating an indexed (i.e., multiplexed) ion source. In the method described, each of the flow streams from a parallel array of HPLC columns is directed toward the multiplexed (MUX) ion source and sampled in a time-dependent, parallel manner. A visual basic application has been developed and monitors in real-time the extracted ion current from each sprayer channel. Mass-directed fraction collection is initiated into a parallel array of fraction collectors specific for each of the spray channels. In the first embodiment of this technique, we report on a four-column semipreparative parallel LC/MS system incorporating MUX detection. In this parallel LC/MS application (in which sample loads between 1 and 10 mg on-column are typically made), no cross talk was observed. Ion signals from each of the channels were found reproducible over 192 injections, with interchannel signal variations between 11 and 17%. The visual basic fraction collection application permits preset individual start collection and end collection thresholds for each channel, thereby compensating for the slight variation in signal between sprayers. By incorporating postfraction collector UV detection, we have been able to optimize the valve-triggering delay time with precut transfer tubing between the mass spectrometer and fraction collectors and achieve recoveries greater than 80%. Examples of the MUX-guided, mass-directed fraction purification of both standards and real library reaction mixtures are presented within.