Esther C. Williams

Rapid development of migratory, linear, and serpiginous lesions in association with immunosuppression

A 78-year-old Bulgarian woman presented to the National Institutes of Health (NIH) with a diagnosis of poorly differentiated metastatic carcinoma of unknown origin. The prior month she had been seen at a hospital in Bulgaria for weight loss and a right inguinal mass. NIH pathology review confirmed a poorly differentiated carcinoma with extensive necrosis suggesting squamous cell carcinoma. She was enrolled in a treatment trial at NIH with metastatic disease invading the lungs and lymph nodes (mediastinum, abdomen, and pelvis) and a chemotherapy regimen was started of gemcitabine, carboplatin, and lenalidomide with dexamethasone as an antiemetic. The patient returned on day 8, and a rash of 2 days duration was noted. Immediately before arriving at the dermatology clinic, she developed altered mental status with aphasia and was admitted for neurologic observation. The altered mental status resolved and evaluation revealed only small-vessel ischemia. The patient was also experiencing diarrhea and was found to have elevated transaminases (4- to 7-fold over normal). Chemotherapy was held because of the transaminase abnormalities and altered mental status. The following day, the patient was seen by dermatology for a progressive asymptomatic eruption.

Peripheral blood stem cell transplant-related Plasmodium falciparum infection in a patient with sickle cell disease.

BACKGROUND: Although transmission of Plasmodium falciparum (Pf) infection during red blood cell (RBC) transfusion from an infected donor has been well documented, malaria parasites are not known to infect hematopoietic stem cells. We report a case of Pf infection in a patient 11 days after peripheral blood stem cell transplant for sickle cell disease.

Performance of para-Pak Ultra ECOFIX compared with Para-Pak Ultra formalin/mercuric chloride-based polyvinyl alcohol for concentration and permanent stained smears of stool parasites.

ECOFIX is a mercury and formalin-free fecal preservative that can be used for concentration of stool specimens and preparation of permanently-stained slides. In this study, the standard two-vial ParaPak Ultra system was compared with ECOFIX Ultra for the detection of intestinal parasites. A total of 261 specimens in 92 sets (77 with 3 specimens, 15 with 2 specimens) were collected in ECOFIX, formalin, and low viscosity polyvinyl alcohol (LV-PVA). Concentrations were performed from ECOFIX using Hemo-De and saline and from formalin using ethyl acetate and formalin. To prepare permanently-stained smears, ECOSTAIN (a modification of Wheatleys trichrome stain) was used on ECOFIX material and Wheatleys trichrome stain was used on specimens preserved in PVA. A total of 157 protozoa and helminths were detected; 132 (84.1%) were recovered in formalin/PVA and 129 (82.2%) in ECOFIX. In permanently-stained smears, 139 protozoa were observed, 116 (83.5%) in PVA-preserved material and 117 (84.2%) in ECOFIX. Fecal concentration yielded 111 parasites (103 protozoa and 8 helminths), of which 98 (88.3%) were detected in formalin-fixed stool and 48 (43.2%) in ECOFIX. Significantly fewer ECOFIX-preserved concentrates were positive for Blastocystis hominis (35 versus 15, p-value <0.001) and Endolimax nana (19 versus 2, p-value <0.001). In conclusion, use of the ECOFIX Ultra collection device in combination with ECOSTAIN resulted in largely comparable recovery of enteric parasites to the conventional two-vial ParaPak Ultra system when both sedimentation-concentration and permanently stained smears were performed, and 2-3 specimens per patient were evaluated.

Rapid identification of group A streptococci by the Strep-A-Fluor system

Group A streptococci can be rapidly identified by the Strep-A-Fluor system (Bio-Spec Inc., Dublin, CA), which uses a specific aminopeptidase to hydrolize L-pyrrolidonyl-beta-naphthylamide. In pure subcultured colonies and in isolated colonies from primary culture plates, the Strep-A-Fluor system had 100% sensitivity and 100% specificity compared with the results of Streptex latex agglutination (Wellcome Research Laboratories, Research Triangle Park, NC). However, in mixed culture from primary culture plates, the sensitivity and specificity were 73% and 95%, respectively. Furthermore, in a routine laboratory setting, the sensitivity was only 91% both from pure subcultured colonies and from isolated colonies from primary culture plates. Contamination with organism other than group A streptococci that are capable of hydrolyzing L-pyrrolidonyl-beta-naphthylamide may explain the low specificity in mixed culture. Deterioration of the buffer reagent due to prolonged use may account for the low sensitivity in a routine laboratory setting.

Evaluation of two commercial microtiter cytotoxin assays for the detection of Clostridium difficile toxin B in stool specimens

Two commercial microtiter cytotoxin assays using a fibroblast cell line (Bartels, Baxter Diagnostics, Inc., Deerfield, IL) and an epithelial cell line (Cytotoxi Test, Advanced Clinical Diagnostics, Toledo, OH) were evaluated for their ability to detect Clostridium difficile toxin B in stool specimens. After 48 hours, the assays had comparable sensitivity (90 versus 92%) and specificity (99 versus 98%). Although not statistically significant, the Bartels assay detected more toxin-positive specimens at 24 hours (84 versus 72%, P = 0.089, Fishers Exact Test) and the Cytotoxi assay had fewer nonspecific reactions requiring repeat testing (2.2 versus 1.1%, P = 0.186, Fishers Exact Test). Both cytotoxin assays had comparable analytic performance.