Risk factors for Clostridium difficile stool cytotoxin b among critically ill patients: role of sucralfate.

To identify risk factors other than antimicrobial exposure for Clostridium difficile stool cytotoxin b, subjects admitted to critical care units over 18 months and who had stool cytotoxin assays were evaluated. Twenty-two cases (cytotoxin b-positive) were compared with 125 controls (cytotoxin b-negative). Cases and controls were similar with respect to age, sex, therapeutic index severity score, duration of hospitalization before cytotoxin b testing, and antimicrobial exposure. Adjusted odds ratios (OR) revealed white blood cell count of > 12,000 on the day of stool sampling (OR, 4.0; 95% confidence interval [CI], 1.3-12.4) and sucralfate exposure (OR, 0.15; 95% CI, 0.05-0.42) as significant independent positive and negative risk factors, respectively. Sucralfate exposure may decrease risk for C. difficile stool cytotoxin b by interfering with its detection, altering toxin production, or inhibiting colonization by the organism. Additional evaluation is needed to elucidate the mechanisms involved.

Risk factors for urinary lithotripsy-associated sepsis.

OBJECTIVES: To identify risk factors for sepsis following urinary extracorporeal shock wave lithotripsy (ESWL). DESIGN: Retrospective case-control study with two control groups. SETTING: A rural, 570-bed, regional referral center. RESULTS: Six cases (four bacteremias and two fungemias) were compared with two sets of 18 controls. Cases had a higher frequency and number of urinary tract infections prior to the procedure and tended to have larger stone size. CONCLUSIONS: Patients undergoing ESWL who are at high risk for infectious complications may be identified by preprocedure evaluation. Such patients may require alternative prophylactic regimens and close postprocedure follow-up.

Nocardial meningitis: case reports and review.

Twenty-eight episodes of nocardial central nervous system infection fulfilling criteria for meningitis were reviewed. In 21 cases Nocardia was cultured from cerebrospinal fluid (CSF). Associated predisposing conditions were present in 75% of cases. The typical presentation was subacute to chronic meningitis characterized by fever (68%), stiff neck (64%), and headache (55%). CSF studies revealed neutrophilic pleocytosis (83% of cases, greater than 500 white blood cells/mm3), hypoglycorrhachia (64%, less than 40 mg of glucose/dL), and elevated protein level (61%, greater than 100 mg/dL). In 43% of cases there was an associated brain abscess. Patients with brain abscess had more frequent and severe aberrations in mental status as well as higher initial white blood cell counts in CSF. Mortality was 52% for the 23 cases diagnosed antemortem and 57% overall. Compared with patients who died, survivors were younger, had lower initial CSF glucose levels, and were less likely to have brain abscess. Diagnosis was often delayed, and nocardial infection was rarely suspected before positive culture reports or autopsy findings became available.

Refrigerated storage of washed red cells.

Red cells washed and stored in a citrate-phosphate-glucose-adenine solution at pH 7.4-7.6 demonstrate excellent maintenance of adenosine triphosphate, elevation of 2,3-diphosphoglycerate well above normal levels for more than 6 weeks, reduced hemolysis and 24-hour in vivo survival comparable to that of cells stored in ADSOL. These results can be attributed in part to a chloride shift in which the washout of intracellular chloride is associated with an influx of OH-, which increases intracellular pH and thereby increases the rate of glycolysis. The phosphate functions primarily as a buffer to maintain both extra- and intracellular pH. Reducing the effective osmolality of the storage solution reduces hemolysis and improves cell morphology.

Pyogenic sacroiliitis in a rural population.

We describe 10 cases of pyogenic sacroiliitis occurring in a rural population. Seven were male and 3 were female with a mean age of 22.4 years. None was a recent intravenous drug abuser. Five patients had a history of recent pelvic trauma. 99mTechnetium scintiscans revealed increased sacroiliac (SI) joint uptake in 8 of 8 cases. Blood cultures were positive in 60% of patients. Staphylococcus aureus was isolated in 7 cases from blood and/or SI aspirates and Hemophilus influenzae type B in one case. Nine of 10 patients recovered completely. One underwent arthrodesis for recurrent SI pain without evidence of relapse of infection. Median followup was 18 months.

Risk factors for nosocomial candidemia: a case-control study in adults without leukemia.

PURPOSE: The purpose of this study was to define risk factors for nosocomial candidemia in adult patients without leukemia at a tertiary care medical center. PATIENTS AND METHODS: All patients with nosocomial candidemia between August 1, 1981, and October 31, 1984, were included if they met strict selection criteria and did not have acute or chronic leukemia. For each case, one control was selected from among patients admitted during the same month/year and matched for hospital service and duration of hospitalization up to the first blood culture that grew Candida species. Logistic regression was used to obtain estimates of risk after simultaneously controlling for other variables. RESULTS: Candida albicans caused 24 of the 48 fungemias studied. The risk factors identified included the presence of a central line (odds ratio, 26.4; 95% confidence interval, 1.5 to 451.1); bladder catheter (13.0 1.3 to 131.4); two or more antibiotics (25.1, 2.1 to 318); azotemia (22.1, 2.2 to 223.2); transfer from another hospital (21.3, 1.7 to 274.5); diarrhea (10.2, 1.03 to 101.4); and candiduria (27.0, 1.7 to 423.5). A prior surgical procedure was associated with lowered risk (0.1, 0.01 to 0.9), suggesting perhaps that medical service patients are at higher risk than those on surgical services. Because total parenteral nutrition was always administered by means of a central line, it could not be shown to increase the risk over that conferred by a central line alone. CONCLUSIONS: This study has defined seven major risk factors for nosocomial candidemia. These findings should facilitate development of rational approaches to preventing infection and may assist clinicians in identifying those patients in whom this life-threatening complication is likely to occur.

Injury from silage wagon accident complicated by mucormycosis.

Infection due to farm machinery injuries may be caused by microorganisms found in soil or decaying vegetable material. A case of injury due to entrapment of a young boy in a silage wagon is reported here. His injuries were complicated by infection with Aspergillus species, Absidia species, Rhizopus species (the latter two are members of the Mucorales order), and Pseudomonas maltophilia. Successful treatment of his infection followed aggressive surgical debridement of the anterior abdominal wall, amphotericin B, hyperbaric oxygen therapy, and surgical closure utilizing delayed placement of split-thickness skin grafts.

Vitrification of human monocytes.

Human monocytes purified from peripheral blood by counterflow centrifugal elutriation were cryopreserved in a vitreous state at 1 atm pressure. The vitrification solution was Hanks' balanced salt solution (HBSS) containing (w/v) 20.5% Me2SO, 15.5% acetamide, 10% propylene glycol, and 6% polyethylene glycol. Fifteen milliliters of this solution was added dropwise to 1 ml of a concentrated monocyte suspension at 0 degrees C. Of this, 0.8 ml was drawn into silicone tubing and rapidly cooled to liquid nitrogen temperature, stored for various periods, and rapidly warmed in an ice bath. The vitrification solution was removed by slow addition of HBSS containing 20% fetal calf serum. The numerical cell recovery was about 92% and most of these retained normal phagocytic and chemotactic ability. Differential scanning calorimeter records of the solution show a glass transition at -115 degrees C during cooling and warming, but no evidence of ice formation during cooling. Devitrification occurs at about -70 degrees C during warming at rates as rapid as 80 degrees C/min. The amount of devitrification is dependent upon the warming rate. Freeze-fracture freeze-etch electron microscope observations revealed no ice either intra- or extracellularly in samples rapidly cooled to liquid nitrogen temperatures except for small amounts in some cellular organelles. However, if these cell suspensions were warmed rapidly to -70 degrees C and then held for 5 min, allowing devitrification to occur, the preparation contained significant amounts of both intra- and extracellular ice. Biological data showed that this devitrification was associated with severe loss of cell function.

Effect of cryoprotectants on the viability and function of unfrozen human polymorphonuclear cells.

High concentrations of membrane permeable cryoprotectants are necessary to protect human polymorphonuclear leukocytes from osmotic stress injury during freezing, but there are reports that some cryoprotectants are chemically toxic. Cells were exposed to various concentrations of glycerol, dimethyl sulfoxide, or ethylene glycol for 5 min to 2 hr at 37, 22 or 0 degree C, adding or removing the cryoprotectant either slowly or rapidly. Assays included cell number recovery, membrane integrity, phagocytosis, microbicidal ability, and chemotaxis. We conclude that (1) 1 and 2 M concentrations generally are not toxic if they are added and removed slowly at 22 degrees C; (2) addition and removal of glycerol at 0 degree C was injurious even at 1 M; (3) slow addition and removal allowed better recovery than rapid addition or removal; (4) salt concentration in cryoprotectant solutions should be adjusted to isotonic on the basis of moles per liter of solution, rather than moles per kilogram of water; (5) the toxicity reported by other investigators can be largely explained by osmotic stress or dilution shock rather than chemical toxicity; and (6) ethylene glycol is the easiest cryoprotectant to add to and remove from these cells.

The preparation of leukocyte-poor red blood cells: a comparative study.

Thirteen methods of prepararing leukocyte-poor red blood cells were compared for their effectiveness in removing leukocytes. When the starting material was six to ten days old, the residual leukocyte count was three to four times lower than when fresh material was used and no granulocytes could be found. The most effective manual procedure was a single upright sedimentation of six- to ten-day-old saline-diluted red cells. Inverted sedimentation was no more effective in leukocyte depletion than upright sedimentation. Automated cell processors were no more effective than several of the better manual methods. Freezing and deglycerolizing resulted in a ten-fold improvement in leukocyte removal with less red blood cell loss but at higher cost than the nonfreezing methods. The study indicates that unless the minimal leukocyte count of frozen red blood cells is essential, a single upright sedimentation of saline-diluted, six- to ten-day-old red blood cells is currently the most effective procedure for preparing leukocyte-poor red blood cells.