Computerized interpretation of minimum inhibitory concentration antimicrobic susceptibility testing.

Quantitative antimicrobic susceptibility tests by determining the minimum inhibitory concentration (MIC) are becoming more and more prevalent in United States laboratories. Interpretation of MIC values is complex and should be considered as part of the laboratory service. This communication provides a simple computerized scheme for MIC interpretation that has been used for more than three years in the authors' laboratories. This computer algorithm provides a semigraphic output documenting relative susceptibility for a matrix of various dosages and sites of the body. Additional features, such as consideration of beta-lactamase production for Staphylococcus aureus and toxic levels for aminoglycosides, are considered in this algorithm. In addition, the authors present a compendium of achievable levels for a comprehensive list of antimicrobics, together with literature reference documentation.

Clinical study of gastrointestinal complications associated with clindamycin therapy.

The incidence of and factors associated with diarrhea were evaluated in 1,000 patients receiving clindamycin. Diarrhea occurred in 6.6% of the patients, and of the many parameters evaluated, a significant association with diarrhea was found only for age (higher incidence in patients older than 20 years), sex (higher incidence in females), and route of administration (higher incidence with oral than with parenteral administration). It is of interest that we were unable to find a positive correlation between dose of drug or duration of therapy and diarrhea. Diarrhea began within 48 hr of start of clindamycin therapy in 52.3% of the patients and within five days of therapy in 75.3%. Nineteen patients developed diarrhea after they had stopped receiving the drug. Duration of diarrhea varied considerably, with a mean of 11.4 days and a range of one to 120 days.

Gastrointestinal side effects associated with clinidamycin. 1,000 consecutive patients.

The incidience and parameters associated with diarrhea related to clindamycin usage were studied in a population of both inpatients and outpatients. Diarrhea occurred in 66 (6.6%) of the 1,000 patients. In three of them, substantial morbidity was associated with the diarrhea. Of the multiple parameters that were evaluated, significant association with diarrhea was found only for age (patients over the age of 20 years) (P less than .01) and sex (females) (P less than .005). Interestingly, dose, duration, and route of administration showed no significant relationship to diarrhea (P greater than .05).

Dichotomy between macrophage activation and degree of protection against Listeria monocytogenes and Toxoplasma gondii in mice stimulated with Corynebacterium parvum.

In vivo and in vitro experiments were conducted to determine the effect of Corynebacterium parvum treatment of mice on resistance of Listeria monocytogenes and Toxoplasma gondii. Intravenous immunization with C. parvum conferred transient protection against intravenous challenge with Listeria or an avirulent strain of Toxoplasma but did not protect against a virulent strain of Toxoplasma. Compared with the level of protection conferred by C. parvum, a higher degree of resistance was noted when mice infected with Listeria or Toxoplasma were challenged with the homologous infecting organism. Peritoneal macrophages from mice immunized intravenously with C. parvum were activated to kill Toxoplasma in vitro. Whereas resistance to challenge in vivo was transient, this population of activated macrophages persisted. Peritoneal macrophages from C. parvum mice also markedly inhibited [3H]thymidine uptake by L cells.