Inoculum size and lot-to-lot variation as significant variables in the tube coagulase test for Staphylococcus aureus

Inoculum size and lot-to-lot variation as significant variables in the tube coagulase test for Staphylococcus aureus.

For a positive coagulase test with certain isolates of Staphylococcus aureus, inoculation of 0.5 ml of coagulase plasma with at least two colonies and 24 h of incubation at 35 to 37 degrees C may be required. S. aureus does not multiply in coagulase plasma. There is also lot-to-lot variation in the sensitivity of coagulase plasma. On isolates from critical specimens, a negative coagulase test o...

Variation of bound coagulase of Staphylococcus aureus.

Duthie (1954) reported that bound coagulase (clumping factor) of staphylococei is released from the surface of autolysing cells into the medium of old broth cultures. Rosenblum and Jackson (1957) noticed occasional alteration of bound coagulase and pigment production after storage of staphylococci for months to years. Decrease in bound coagulase activity of freshly isolated hospital strains of ...

How to Use MRP in Continuous Production Industries When Order Type is Lot for Lot

The Materials Requirements Planning (MRP) method that is applied in production planning and management has some weaknesses. One of its weaknesses is that the time in MRP method is discrete, and is considered as time period. Hence we are not able to order our requirements at irregular time moments or periods. In this paper, a new form of MRP is introduced that is named Continuous Materials Requi...

Lot-to-lot variation in anti-hepatitis C signal-to-cutoff ratio.

Lot-to-Lot Variation in Anti-Hepatitis C Signal-to-Cutoff Ratio, D. Robert Dufour (Pathology and Laboratory Medicine Service, Veterans Affairs Medical Center, and Department of Pathology, The George Washington University Medical Center, Washington, DC; address for correspondence: Pathology and Laboratory Medicine Service-113, Veterans Affairs Medical Center, 50 Irving St. NW, Washington DC 2042...

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