Bacillus Species Pseudomeningitis

Abstract

A cluster of cerebrospinal fluid Gram's stains showing gram-positive bacilli and of cerebrospinal fluid cultures growing Bacillus species in a large community teaching hospital prompted an epidemiologic and microbiologic investigation. Pseudomeningitis was suspected and confirmed when cultures of uninoculated commercial trypticase soy broth with 5% Fildes enrichment grew Bacillus species. Secondary contamination of the pipettes used for inoculation accounted for the positive cerebrospinal fluid Gram's stains. The costs of this pseudo-outbreak included unnecessary antibiotic therapy, lumbar punctures, and hospitalization. Such adverse effects can be minimized by increased physician awareness of pseudoinfections and by prompt investigation of such occurrences.

A pseudo-outbreak of salmonellosis

“…Contamination of laboratory equipment and bronchoscopes have been reported in earlier pseudo-outbreaks [6][7][8][9]. Other reported pseudo-outbreaks have been associated with atypical mycobacteria in a hospital water supply [10], misidentifi-cations of E. histolytica [11], cryptosporidial oocysts [12], possible technical faults in the technique for taking blood cultures [12][13][14][15][16] and misinterpretation of laboratory tests for infectious mononucleosis and TB [3,17].…”

The effect of filters on aseptic pipetting lifetime of mechanical and electronic pipettors and carryover during pipetting

“…Carryover from contaminated pipetting devices may lead to erroneous results, such as incorrect bacterial counts (Corpet 1986) or to false clinical data leading to wrong treatment of patients (Lettau et al 1988). Traditionally bacteriological work has been conducted with serological pipettes or Pasteur pipettes, with a piece of cotton as a filter in the upper end.…”