Methicillin-resistant Staphylococcus aureus: comparison of susceptibility testing methods and analysis of mecA-positive susceptible strains.

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for an increasing number of serious nosocomial and community-acquired infections. Phenotypic heterogeneous drug resistance (heteroresistance) to antistaphylococcal beta-lactams affects the results of susceptibility testing. The present study compared the MRSA-Screen latex agglutination test (Denka Seiken Co., Ltd., Tokyo, Japan) for detection of PBP 2a with agar dilution, the VITEK-1 and VITEK-2 systems (bioMérieux, St. Louis, Mo.), and the oxacillin agar screen test for detection of MRSA, with PCR for the mecA gene used as the "gold standard" assay. Analysis of 107 methicillin-susceptible S. aureus (MSSA) isolates and 203 MRSA isolates revealed that the MRSA-Screen latex agglutination test is superior to any single phenotype-based susceptibility testing method, with a sensitivity of 100% and a specificity of 99.1%. Only one isolate that lacked mecA was weakly positive by the MRSA-Screen latex agglutination test. This isolate was phenotypically susceptible to oxacillin and did not contain the mecA gene by Southern blot hybridization. The oxacillin agar screen test, the VITEK-1 system, the VITEK-2 system, and agar dilution showed sensitivities of 99.0, 99.0, 99.5, and 99%, respectively, and specificities of 98.1, 100, 97.2, and 100%, respectively. The differences in sensitivity or specificity were not statistically significant. Oxacillin bactericidal assays showed that mecA- and PBP 2a-positive S. aureus isolates that are susceptible to antistaphylococcal beta-lactams by conventional methods are functionally resistant to oxacillin. We conclude that the accuracy of the MRSA-Screen latex agglutination method for detection of PBP 2a approaches the accuracy of PCR and is more accurate than any susceptibility testing method used alone for the detection of MRSA.

Molecular typing of coagulase-negative staphylococci from blood cultures does not correlate with clinical criteria for true bacteremia.

PURPOSE: Determining whether a blood culture that contains coagulase-negative staphylococci represents bacteremia or contamination is a clinical dilemma. We compared molecular-typing results of coagulase-negative staphylococcal blood culture isolates with clinical criteria for true bacteremia. SUBJECTS AND METHODS: Pulsed-field gel electrophoresis and arbitrary primed polymerase chain reaction (PCR) were used to determine whether patients with two or more blood cultures with coagulase-negative staphylococcal isolates had the same strain of organism in each culture (same strain bacteremia). We evaluated three different clinical criteria for bacteremia: whether the patient received more than 4 days of antibiotics, whether there was an explicit note in the medical chart in which the physician diagnosed a true bacteremia, and the Centers for Disease Control surveillance criteria for primary bloodstream infection. Agreement between same-strain bacteremia and each definition was examined, based on the assumption that most true infections should be the result of a single strain. RESULTS: The study sample consisted of 42 patients and 106 isolates. Nineteen of the 42 bacteremias (45%) were the same strain. Classification of bacteremias as same-strain correlated poorly with all three clinical assessments (range of percent agreement, 50% to 57%; range of kappa statistic, 0.01 to 0.15). There were both false-positive and false-negative errors. Patients with three or more positive blood cultures were more likely to have same-strain bacteremia than those with only two positive cultures [11 of 15 (73%) vs 8 of 27 (30%), P = 0.006]. Pulsed-field gel electrophoresis was more discriminating than arbitrary primed PCR (percent agreement, 83%; kappa, 0.67). CONCLUSION: Molecular typing correlated poorly with clinical criteria for true bacteremia, suggesting either that true bacteremias are frequently the result of multiple strains or that the commonly used clinical criteria are not accurate for distinguishing contamination from true bacteremia. Vancomycin treatment of clinically defined coagulase-negative staphylococcal bacteremia may frequently be unnecessary.

Vancomycin-resistant enterococci in intensive care units: high frequency of stool carriage during a non-outbreak period.

BACKGROUND: We aimed to define the epidemiological associations of vancomycin-resistant enterococci (VRE) in intensive care units (ICUs) during a non-outbreak period by examining prevalence, risk factors for colonization, frequency of acquisition, and molecular strain types. DESIGN: A prospective cohort design was followed. Consecutive patient admissions to 2 surgical ICUs at a tertiary care hospital were enrolled. The main outcome measures were results of serial surveillance cultures screened for VRE. RESULTS: Of 290 patients enrolled, 35 (12%) had colonization with VRE on admission. The VRE colonization or infection had been previously detected by clinical cultures in only 4 of these patients. Using logistic regression, VRE colonization at the time of ICU admission was associated with second- and third-generation cephalosporins (odds ratio [OR] = 6.0, P<.0001), length of stay prior to surgical ICU admission (OR = 1.06, P = .001) greater than 1 prior ICU stay (OR = 9.6, P = .002), and a history of solid-organ transplantation (OR = 3.8, P = .021). Eleven (12.8%) of 78 patients with follow-up cultures acquired VRE. By pulsed-field gel electrophoresis, 2 strains predominated, one of which was associated with an overt outbreak on a non-ICU ward near the end of the study period. CONCLUSIONS: Colonization was common and usually not recognized by clinical culture. Most patients who had colonization with VRE and were on the surgical ICU acquired VRE prior to surgical ICU entry. Exposure to second- and third-generation cephalosporins, but not vancomycin, was an independent risk factor for colonization. Prospective surveillance of hospitalized patients may yield useful insights about the dissemination of nosocomial VRE beyond what is appreciated by clinical cultures alone.

Carriage of methicillin-resistant Staphylococcus aureus at hospital admission.

OBJECTIVES: To measure the prevalence of, and to establish predictors for, the nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) at hospital admission. To evaluate mannitol-salt agar with oxacillin for the simultaneous detection and identification of MRSA from nasal swabs. DESIGN: Three-month prospective case-control survey, with data collected from interviews and computerized databases. The criterion standard for MRSA detection was culture on Mueller-Hinton agar with oxacillin 6 microg/mL (National Committee for Clinical Laboratory Standards method). SETTING: 320-bed tertiary-care hospital. PATIENTS: 387 patients screened within 24 hours after admission, including 10 MRSA carriers (cases), 291 patients with no S aureus, and 86 patients with methicillin-susceptible S aureus. RESULTS: The prevalence of MRSA nasal carriage was 2.6%, whereas the prevalence of carriage was 3.1% when both nasal and wound cultures were performed. The significant predictors of carriage were a prior detection of MRSA, open wounds, diabetes mellitus, treatments by injection, prior nursing home stays, visits at home by a nurse, and prior antibiotic treatments. Cases had stayed for longer periods in hospitals and had received longer antibiotic treatments within a year. Eighty patients (including the 10 cases) had diabetes, had been exposed to healthcare facilities within a year, and had antibiotics within 6 months. The sensitivity and negative predictive value of nasal swabs on mannitol-salt agar with oxacillin were 60% and 71%, respectively. CONCLUSION: MRSA carriage on admission to the hospital may be an increasing and underestimated problem. Further studies are needed to develop and validate a sensitive and specific prediction rule.

Stool colonization of healthcare workers with selected resistant bacteria.

We examined the carriage of selected resistant bacteria in the stools of healthcare workers who provided direct patient care. Neither vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, nor Clostridium difficile was recovered from the 55 stool specimens collected. A ceftazidime-resistant Citrobacter freundii was isolated from one specimen. We conclude that the stool of healthcare workers is colonized infrequently with these resistant organisms.

Parasitic sinusitis and otitis in patients infected with human immunodeficiency virus: report of five cases and review.

We describe five cases of parasitic sinusitis and otitis in patients infected with human immunodeficiency virus (HIV) and review 14 reported cases. The pathogens identified in our group of patients included agents such as Microsporidium, Cryptosporidium, and Acanthamoeba species. The clinical features common to these patients included a long history of HIV seropositivity associated with advanced immunosuppression and multiple opportunistic infections as well as long-standing local symptoms refractory to multiple courses of antibacterial agents. Symptoms often included fever and chills in addition to local tenderness and discharge. Invasive diagnostic procedures were necessary to obtain the final diagnosis and to initiate appropriate therapy. Although most patients responded at least partially to specific therapy, relapses and recurrences were frequent in patients who did not receive long-term suppressive therapy. The general outcome for HIV-infected patients with parasitic sinusitis and otitis was poor; however, deaths were generally associated with other complications of the underlying HIV infection.

A medium chain triglyceride-based diet in patients with HIV and chronic diarrhea reduces diarrhea and malabsorption: a prospective, controlled trial.

Our objective was to determine whether a medium-chained triglyceride (MCT)-based diet, compared to a long-chain triglyceride (LCT)-based diet, conveys a beneficial effect on diarrhea and fat malabsorption in human immunodeficiency virus (HIV)-infected individuals with chronic diarrhea and weight loss. A secondary objective was to evaluate the pathogens associated with the diarrhea and to evaluate whether the etiologic agent was a determinant of response to the nutritional intervention. Prospective, randomized double-blind comparative trial was conducted in 24 adult patients with HIV, diarrhea of greater than 4-wk duration, fat malabsorption, and loss of 10-20% of ideal body weight, these patients were recruited from our outpatient infectious disease clinic. Evaluations of diarrheal pathogens were made by complete stool examination, upper and lower endoscopy with quantitative culture, and biopsy. Body composition determinations, and measurements of fat, carbohydrate, and vitamin absorption pre- and postintervention. Patients were randomly assigned to one of two complete nutritional products with either medium- or long-chain triglyceride fat exclusively for 12 d followed by treatment of infectious pathogens. Ten patients were found to have Microsporidium and 9 patients had no identifiable pathogen. All patients responded to intervention with both nutritional products overall with 45% fewer stools, decreased stool fat and weight, and a significant increase in urine nitrogen. The group that received the MCT product demonstrated significantly decreased stool number (mean 4 to 2.5), stool fat (mean 14 to 5.4 g), and stool weight (mean 428 to 262 g) compared with baseline (P < 0.01 for all). Patients with both species of microsporidia and with pathogen negative diarrhea had good response. We found that HIV patients with diarrhea, regardless of etiology, and documented fat malabsorption may benefit symptomatically from a diet composed of an MCT-based liquid supplement.

Comparison of PCR-based approaches to molecular epidemiologic analysis of Clostridium difficile.

Representative isolates of the 10 serogroups of Clostridium difficile and 39 clinical isolates (30 toxigenic and 9 nontoxigenic), including 5 isolates from a confirmed nosocomial outbreak, were analyzed by using two previously described arbitrary-primer PCR (AP-PCR) molecular typing methodologies (AP-PG05 and AP-ARB11) and PCR ribotyping. The two AP-PCR methods investigated gave comparable results; AP-PG05 and AP-ARB11 identified 8 and 7 groups among the serogroup isolates and classified the clinical isolates into 21 and 20 distinct groups, respectively. PCR ribotyping also identified 8 unique groups among the serogroup isolates but classified the clinical isolates into 23 groups. In addition, when results obtained by the PCR methods were compared with typing data generated by pulsed-field gel electrophoresis (PFGE), PCR ribotyping and PFGE were found to be in agreement for 83% (29 of 35) of isolates typeable by both techniques while AP-PG05 was in agreement with PFGE for 60% (20 of 33) and AP-ARB11 was in agreement with PFGE for only 44% (17 of 36). These results indicate that PCR ribotyping is a more discriminatory approach than AP-PCR for typing C. difficile and, furthermore, that this technique generates results that are in higher concordance with those obtained by using an established method for differentiating isolates of this organism on a molecular level than are results generated by using AP-PCR.

Clinical and molecular epidemiology of sporadic and clustered cases of nosocomial Clostridium difficile diarrhea.

PURPOSE: A prospective clinical and molecular epidemiologic study was conducted to define the frequency of nosocomial Clostridium difficile patient-to-patient transmission in an urban tertiary referral hospital. PATIENTS AND METHODS: Over a 6-month period, environmental cultures for C difficile were obtained from patients with new positive stool cytotoxin assay (index cases); stool samples were obtained from selected patient contacts (the roommate, occupants of adjacent rooms, and the patient occupying the index room after discharge of the index case); and hand cultures were obtained from personnel contacts. C difficile isolates were analyzed by pulse-field gel electrophoresis (PFGE) or, for isolates that were nontypeable by PFGE, by restriction enzyme analysis. RESULTS: During the study period, we identified 98 index cases of C difficile toxin-associated diarrhea, including focal outbreaks on two wards totaling 26 cases within a 2-month interval. Environmental contamination was detected at > or = 1 sites in 58% of rooms and often involved wide dispersed areas. Among 99 prospectively identified patient contacts, C difficile was cultured from the stool of 31 (31%), including 12 with diarrhea and 19 who were asymptomatic. C difficile was cultured from the hands of 10 (14%) of 73 personnel. Molecular analysis resolved 31 typing profiles among the index isolates; the most common profile (designated strain D1) was represented by 30 isolates. Among the isolates from patient contacts, 5 of 12 from symptomatic contacts matched the corresponding index isolate, and only 1 of 19 from asymptomatically colonized contacts matched. Transmission to personnel or patient contacts of the strain cultured from the corresponding index case was correlated strongly with the intensity of environmental contamination. Strain D1 was frequently represented among isolates associated with heavy environmental contamination, with personnel carriage, and with development of symptomatic illness among prospectively identified contacts. CONCLUSIONS: Intense environmental contamination and transmission to close personnel and patient contacts represented coordinated properties of an individual epidemic strain. For most epidemiologically linked contacts, positive cultures for C difficile did not result from transmission from the presumed index case.

Multiorgan microsporidiosis: report of five cases and review.

We describe five cases and review 34 reported cases of multiorgan microsporidiosis. Most of the patients with multiorgan involvement have been adults with AIDS. Organs most commonly infected include the small intestine, urinary tract, biliary tree, and eye; involvement of the respiratory tract, nasal sinuses, and central nervous system is also described but appears to be less frequent. Although patients with multiorgan disease may be asymptomatic, clinical presentation usually relates to the involved organs. Enterocytozoon bieneusi and Septata intestinalis are the most frequently identified species of pathogens. An affinity for certain tissues is observed among different microsporidial species. In all but one case of E. bieneusi infection, infection was limited to intestinal and hepatobiliary tracts, a finding suggestive of local extension. In contrast, the patients infected with S. intestinalis had widespread involvement, suggesting true hematogenous or lymphatic dissemination. Treatment may have to be based on findings regarding which organs and specific microsporidial species are involved. Further investigation of the pathogenic tendencies and route of acquisition of these organisms and the therapeutic agents active against them is needed.

Diagnosis of intestinal microsporidiosis by examination of stool and duodenal aspirate with Weber's modified trichrome and Uvitex 2B strains.

Severe, chronic diarrhea is a frequent complication of human immunodeficiency virus disease, and intestinal microsporidiosis is being recognized with increasing frequency in patients with AIDS. Noninvasive, cost-effective techniques are needed to optimize its diagnosis. Weber's modified trichrome stain (MTS) and the fluorochrome Uvitex 2B stain were used to detect microsporidial spores in smears of stool and duodenal aspirate (DA) samples received from human immunodeficiency virus-infected patients for examination for ova and parasites. Of 305 samples (292 stool and 13 DA samples) from 140 patients examined by MTS, 83 samples from 26 (18.6%) of the patients were positive for microsporidia (23 patients diagnosed initially and 3 diagnosed upon review). A subset of the samples studied by MTS consisting of 108 smears of stool and DA specimens from 60 patients was examined by Uvitex 2B. All 44 samples positive by MTS were also positive by Uvitex 2B. In addition, seven specimens and three patients were initially detected as positive by Uvitex 2B only (all three patients were positive also by MTS upon review). Confirmation of the diagnosis was obtained for 24 of 26 smear-positive patients by duodenal biopsy and/or stool transmission electron microscopy. Of 114 patients with stained smears negative for microsporidia, 23 had duodenal biopsies which showed no microsporidia. For the 43 patients who underwent duodenal biopsy, the sensitivity of both the MTS and the Uvitex 2B methods compared with biopsy results was 100%. Of six patients with negative duodenal biopsies and positive stained smears, four had microsporidia demonstrated by stool transmission electron microscopy. The examination of stool and DA smears stained by Uvitex 2B and/or MTS is a sensitive, noninvasive test for diagnosis of intestinal microsporidiosis which can be successfully implemented in a clinical laboratory. Strict adherence to precise diagnostic criteria is necessary to avoid incorrect results. The simultaneous use of both staining methods enhances performance and may provide greater accuracy, especially for patients with light infections.

Wide diversity of Clostridium difficile types at a tertiary referral hospital.

Nosocomial Clostridium difficile infection was investigated at a hospital with 15 cases of C. difficile diarrhea per 1000 discharges. From January 1991 to May 1991, patients admitted or transferred to five wards or units had weekly rectal swabs taken for culture; in addition, all cytotoxin-positive stools were cultured. Restriction enzyme analysis (REA) was used for molecular typing. Among 205 isolates from 39 patients with C. difficile diarrhea and 67 asymptomatically colonized, 55 distinct REA banding patterns were identified. Evidence for patient-to-patient transmission was limited, in that numerous strains were found even among clustered cases of diarrhea. Patients who acquired C. difficile in the community or other hospitals constituted 32% of culture-positive patients and contributed 44% of the REA types. Diversity of C. difficile strains was in part the result of patients acquiring C. difficile in the community or other hospitals. High incidences of nosocomial C. difficile diarrhea do not necessarily indicate clonal epidemics.

Comparison of restriction endonuclease analysis, ribotyping, and pulsed-field gel electrophoresis for molecular differentiation of Clostridium difficile strains.

A combined clinical and molecular epidemiologic analysis of 46 strains of Clostridium difficile, including 16 nosocomial isolates from one ward (outbreak ward) plus 17 other nosocomial isolates and 13 community-acquired isolates, was performed. HindIII digests of total cellular DNA were analyzed by restriction enzyme analysis (REA) and ribotyping; SmaI digests were analyzed by pulsed-field gel electrophoresis (PFGE). Isolates were assigned to typing groups on the basis of the profiles detected; isolates with closely related profiles were assigned to subgroups. The 16 isolates from the outbreak ward were resolved by both REA and PFGE into five distinct groups; 13 isolates represented two REA groups and three PFGE groups and two isolates were resolved as distinct groups by both techniques. DNA obtained from one isolate was persistently partially degraded, precluding analysis by PFGE. Seventeen sporadic nosocomial isolates were resolved by REA and PFGE into comparable numbers of groups (i.e., nine groups) and subgroups (i.e., 15 and 14 subgroups, respectively), with two isolates not evaluable by PFGE. The 13 epidemiologically unrelated community-acquired isolates were assigned to 11 groups by REA and to 12 groups by PFGE. Overall, ribotyping identified only nine groups among the 46 isolates. We conclude that REA and PFGE have comparable discriminatory powers for epidemiologic typing of C. difficile isolates and that ribotyping is appreciably less discriminatory. For a few isolates, partial DNA degradation prevented analysis by PFGE but not by REA or ribotyping; the cause of the degradation is unknown.

Clinical features of microsporidiosis in patients with AIDS.

Microsporidia are protozoan parasites responsible for significant gastrointestinal disease in patients infected with human immunodeficiency virus. We report the clinical features of 20 patients with chronic diarrhea for whom microsporidian spores were identified by modified trichrome staining of stool smears and confirmed by biopsy and/or electron microscopy of stool. Of the 18 microsporidian protozoa identified to the species level, 14 (78%) were Enterocytozoon bieneusi and four (22%) were Septata intestinalis. The mean CD4 count in these patients was 35 +/- 29 cells/mm3. Parameters of absorption, specifically absorption of fat and D-xylose, and levels of zinc were strikingly abnormal in patients who were tested. Treatment with albendazole led to clinical responses in six of 10 patients, and dietary manipulation resulted in clinical improvement in eight of nine patients. We recommended that patients with chronic, intermittent diarrhea and CD4 counts of < 100 cells/mm3 be further evaluated for microsporidia by modified trichrome staining of stool and light and electron microscopy of small bowel biopsy specimens. Antiprotozoal therapies are currently experimental, but some patients who have been treated with these therapies have dramatic responses. We also recommend that special attention be paid to the measurement of parameters of absorption with appropriate modification of diet.

Clostridium difficile colonization and diarrhea at a tertiary care hospital.

Clostridium difficile is the major identifiable infectious cause of nosocomial diarrhea. A prospective study was conducted at New England Deaconess Hospital (Boston) to examine risk factors for C. difficile carriage at both admission and follow-up. Specimens from patients admitted to two wards (one medical, one surgical) and three intensive care units (two surgical, one medical) were cultured weekly until discharge. For 89 (18%) of 496 patient admissions, at least one culture was positive. The prevalence of culture positivity within 72 hours of admission was 11%. Risk factors for culture positivity at admission were prior C. difficile diarrhea (adjusted odds ratio [OR] = 9.5), renal insufficiency (OR = 6.7), and recent hospitalization elsewhere (OR = 3.1). Fifteen percent of patients for whom initial cultures were negative and for whom follow-up cultures were performed acquired C. difficile. Admission to the vascular surgery service (relative risk [RR] = 2.3) and liver transplantation (RR = 4.2) were significant risk factors for C. difficile acquisition. Patients asymptomatically colonized on admission had very low risk (1 in 44) for subsequent development of C. difficile diarrhea. In contrast, nine (47%) of 19 patients who acquired toxigenic strains developed C. difficile diarrhea, a finding suggesting that progression to diarrhea occurs early after acquisition or does not occur at all. The relatively high prevalence of culture positivity at admission may be characteristic of tertiary care hospitals and adds to the difficulty of controlling this nosocomial pathogen.

Protothecosis complicating prolonged endotracheal intubation: case report and literature review.

Prototheca species are ubiquitous, aerobic, unicellular algae closely related to the green algae Chlorella. Their involvement in human disease--in both immunocompetent and immunocompromised patients--has been reported with increasing frequency. The wide array of presentations has included cutaneous, subcutaneous, mucosal, bursal, catheter-related, and (in rare instances) systemic disease. We report a case of protothecosis complicating prolonged endotracheal intubation presenting as a nasopharyngeal ulceration with a soft-tissue mass, and we review the presentation, treatment, and outcome of the 59 previously reported cases of protothecosis. Optimal therapy for protothecosis includes excision (where possible) followed by systemic administration of amphotericin B; the sole exception is in the case of olecranon bursitis, where excision alone appears curative. The role of the newer imidazoles is yet to be determined.

Evaluation of diagnostic methods for Helicobacter pylori gastritis.

The authors evaluated the use of direct Gram-stained smears, 1- and 24-hour urease broth tests, histologic examination, and culture to detect Helicobacter pylori in 100 gastric biopsy specimens from 97 patients with epigastric symptoms. Twenty-six patients had positive cultures and 27 had H. pylori identifiable in hematoxylin and eosin-stained sections. The gastric biopsy specimens from the 29 patients with culture and/or histologic findings positive for H. pylori showed active gastritis in 27 cases (93%), compared with 26 cases (37%) without H. pylori (P less than 0.0001). Chronic gastritis was present in 25 cases (86%) with H. pylori and 40 cases (56%) without H. pylori (P less than 0.01). Twenty patients had positive Gram-stained smears. Fifteen patients had positive 1-hour urease tests, and 3 had delayed positive 24-hour urease tests. There were no false-positive Gram's stain results, three false-positive 24-hour urease tests, two false-negative histologic results, and three false-negative cultures (one inadvertently incubated anaerobically). The sensitivities of the methods were as follows: 62% for the 24-hour urease test, 69% for direct Gram's stain, 90% for culture, and 93% for histologic examination. The authors conclude that the urease test used in this study has low sensitivity and limited specificity; that the direct Gram-stained smear is a useful, highly specific, rapid screening test; and that the lengthier methods of culture and histologic examination have comparably high sensitivity for the definitive diagnosis of H. pylori gastritis.

Human infection caused by Exophiala pisciphila: case report and review.

One year after receiving a liver transplant and 2 months after treatment with high doses of steroids and monoclonal anti-CD3 for an episode of rejection, a 38-year-old woman developed a skin papule above the left medial malleolus. The papule, which at first had an annular shape, evolved into a pustule, ulcerated, drained, and assumed a crusted verrucous appearance. Multiple satellite papules appeared around the lesion, which was incompletely excised and thought to represent squamous cell carcinoma. Review of the histologic slides revealed pseudoepitheliomatous hyperplasia with multiple epidermal and dermal abscesses, pigmented hyphae, and yeast-like forms. Culture of material obtained at reexcision yielded a dematiaceous fungus that was identified as Exophiala pisciphila. No evidence of dissemination was found. This represents a unique report of human infection with this fungus, a well-recognized pathogen of fish. Except for the absence of sclerotic bodies, the clinicopathologic features resembled those of chromoblastomycosis rather than those of the subcutaneous cystic form of phaeohyphomycosis often associated with species of Exophiala.

Pseudallescheria boydii infection of the central nervous system.

Pseudallescheria boydii is a rare cause of central nervous system infection characteristically presenting as a neutrophilic meningitis or multiple brain abscesses. Factors predisposing to central nervous system infection with this fungus include immunosuppression and near drowning. The organism is infrequently cultured from fluid obtained by lumbar puncture, delaying clinical recognition and appropriate antifungal therapy. All untreated patients with P boydii infection of the central nervous system died. We describe a patient who developed a persistent neutrophilic meningitis with focal neurologic deficits due to P boydii 6 months after a freshwater aspiration pneumonia. We also review the characteristic clinical and pathologic features of previously reported cases and emphasize the importance of early detection and treatment in the management of this frequently intractable disease.