Molecular diversity of Clostridium botulinum and phenotypically similar strains.

This study was undertaken to examine phenotypic and genetic features of strains preliminary classified as Clostridium botulinum species. The phenotypic characteristics were assessed with different culture media and biochemical tests. The genetic characterization included detection of botulinum toxin genes by PCR and macrorestriction analysis with SmaI, XhoI and SacII by PFGE (Pulsed-field Gel Electrophoresis). Despite similar biochemical properties of all analysed strains, only 47% of them contained genes determining toxicity specific to C. botulinum species. The most valuable differentiation of C. botulinum and C. botulinum-like strains was obtained after SmaI digestion. The highest affinity was observed among C. botulinum type B profiles which was even up to 100%. It was found 100% of affinity between C. botulinum and C. botulinum-like strains, however, the similarity among C. botulinum and C. botulinum-like was generally lower than 80%.

Methods and difficulties in detection of Clostridium botulinum and its toxins.

The aim of this work was to present selected data regarding traditional and modern methods for C. botulinum and its toxins detection. In this article, methods based on culturing techniques, mouse bioassay, immunological techniques, chromatography and PCR, PFGE, RFLP, AFLP are described. The mentioned techniques were evaluated considering their usefulness in the samples examination, genotyping of strains and the diagnostics of botulism.

Cost of operation and reliability of two brands of volume ventilators.

Maintenance records during 12 months for 16 MA-1 ventilators, 7 BEAR-1 ventilators more than one year old, and 6 new BEAR-1 ventilators were compared. The MA-1 ventilators had the best record in every important category except cost for accessory parts and ventilator cost per patient hour with retrofit and preventive maintenance. The MA-1 ventilators needed repair once every 8,329 hours of use, compared with once every 2,500 hours for older BEAR-1 ventilators and once every 4,277 hours for newer BEAR-1 ventilators. Total costs of repairs were $430.84 for 16 MA-1 ventilators, and $3,064.44 for 7 BEAR-1 ventilators out of warranty. Costs of replacement parts were $3,097.01 for the MA-1 ventilators, $986.21 for the older BEAR-1 ventilators, and $845.32 for the newer BEAR-1 ventilators. The total cost per patient hour of use was 11 for the MA-1 ventilators and 13 and 3 respectively for the two BEAR-1 groups. Adding costs for retrofit for the MA-1 ventilators and projected costs for preventive maintenance of the BEAR-1 ventilators tripled the cost per hour of use for all three groups. The frequency of breakdowns for both brands of ventilators underlines the need for preventive maintenance, but substantial cost increases will result from those programs.

Reliability of three different brands of adult volume ventilators in a one-year period.

The maintenance records covering a 12-month period for 16 Puritan-Bennett MA-1, 7 Bourns BEAR-1, and 3 Siemens-Elema Servo No. 900-B volume ventilators were compared. The MA-1s had an average of 15,555 hours use prior to the study, compared with 200 average hours on each BEAR and 2,600 on each Servo ventilator. The MA-1s required the least number of repairs and operated longest between repairs, with 18,999 average hours of use per repair, compared with 4,955 hours for the BEAR-1 and 599 hours for the Servo ventilator. The average time required for repair was highest for the MA-1. Most repairs to the BEAR-1 were compressor-related and most were performed in the hospital, as were the repairs to the Servo ventilators. All MA-1 repairs were performed at Puritan-Bennett. The technical advantages of the BEAR-1 and Servo ventilators are convenient, but because of the frequency of repair of these units they are probably more suited to institutions where close supervision and technical backup are available.