Exophiala jeanselmei infection in solid organ transplant recipients: report of two cases and review of the literature.

Dematiaceous fungi are an opportunistic pathogen seen in solid organ transplant recipients. We report 2 cases of Exophiala infection and review the medical literature to summarize the spectrum of disease this pathogen can cause in this patient population.

Yersinia enterocolitica: overview and epidemiologic correlates.

Yersinia enterocolitica comprises both pathogenic and nonpathogenic members. Distinguished by biogrouping, serogrouping, and ecological distribution, commonly occurring pathogenic serobiogroups, e.g., O:3/4; O:5,27/2; O:8/1b; O:9/2, possess both chromosomal and plasmid-mediated virulence traits. Studies have revealed several (oral, blood transfusion) modes of acquisition, elucidated the putative role of chromosomal and plasmid-encoded virulence factors in the pathogenesis of human infection, and have identified major animal reservoirs, e.g., the pig. Diagnosis has been refined though use of selective media, monoclonal antibodies directed against outer membrane proteins, and of purified yersiniae outer membrane proteins for antibody detection. Epidemiological investigations of foodborne outbreaks have been advanced through the use of molecular biology techniques such as ribotyping and pulsed-field gel electrophoresis.

"Giant" blastoconidia of Candida albicans: morphologic presentation and concepts regarding their production.

Candida albicans normally produces blastoconidia measuring 2 to 8 microns in diameter. Markedly enlarged "giant" (approximately 30 microns) blastoconidia of a C. albicans isolate (designated BH) were observed after growth on commercially prepared chocolate agar already supplemented with IsoVitalex (BBL-Microbiology Systems, Cockeysville, MD, USA). Morphologically, "giant" blastoconidia presented a spectrum of forms such as blastoconidia with linear creases, with a single broad-based bud resembling Blastomyces dermatididis, with multiple buds resembling Paracoccidioides brasiliensis, or elliptical in shape. "Giant" blastoconidia contained a large oval clear vacuole occupying greater than 50% of the blastoconidium. Pseudohyphae emanating from these blastoconidia were also enlarged and contained a similar oval inclusion. Rarely observed were "giant" blastoconidia with either adherent or internalized blastoconidia uniformly arranged within the blastoconidium. "Giant" or enlarged blastoconidia production was constant, usually approaching 10 to 20% of the blastoconidial units comprising a single colony, irrespective of the number of subcultures. IsoVitalex supplementation of Remel (Lexana, KS, USA) chocolate agar but not a variety of other media also resulted in "giant" blastoconidia production. It is, therefore, theorized that a component(s) of IsoVitalex activates/blocks a gene present in select clones of C. albicans blastoconidia resulting in "giant" or enlarged blastoconidiogenesis.

Encapsulated Enterococcus faecalis: role of encapsulation in persistence in mouse peritoneum in absence of mouse lethality.

Two nonhemolytic, mucoid, encapsulated strains of Enterococcus faecalis lacked lethality for 23 white mice when inoculated (10(9) cells/mL) intraperitoneally. Bacteremia was short lived (2 to 3 days), but peritoneal cultures remained positive for 7 days postinoculation. Although encapsulation did not result in animal lethality, encapsulation may have delayed peritoneal clearance by interference with phagocytosis.

Value of assessing cryptococcal antigen in bronchoalveolar lavage and sputum specimens from patients with AIDS.

Cryptococcus neoformans has become a significant opportunistic pathogen, accounting for 8-10% of infectious complications in patients with AIDS. When encapsulated yeast cells are observed in Giemsa-stained smears of bronchoalveolar washings (BAL), or induced sputum specimens, confirmation as C. neoformans is germane to definitive therapy. We therefore studied 30 BAL and 9 induced sputum specimens for cryptococcal antigen. Of the 30 BAL, 3 specimens were positive for cryptococcal antigen, ranging in titer from 1:4 to 1:256, and 2 of 9 sputum samples were also smear, culture and antigen positive (titer 1:2) for C. neoformans. Of the 34 negative specimens, none of the seven containing Candida species or the one containing H. capsulatum or the one containing P. carinii cross-reacted with cryptococcal anticapsular antibody. Our results indicate that when yeast forms suggestive of C. neoformans are visualized on direct smears of BAL or sputum samples, rapid confirmation as C. neoformans may be achieved by assessment for cryptococcal antigen. A correlation may also exist between antigen titer in respiratory specimens and extent of cryptococcal infection.

Evidence of self-inhibition by filamentous fungi accounts for unidirectional hyphal growth in colonies.

Hyphal growth in filamentous fungi proceeds in an unidirectional radial pattern from a point inoculation. An inhibitor produced, secreted, and absorbed by the advancing hyphae has been speculated to account for directional growth. Working with Mucor and Aspergillus, laboratory evidence is provided for the production of an inhibitory by the advancing hyphae of these filmentous fungi that precludes back growth. Strains of Mucor and Aspergillus inoculated in agar on a 0.45-mm membrane filter placed on agar surfaces grow radially beyond the filter perimeter and onto the agar surface. Removal of the filter pad does not result in hyphal extension back into the clear zone underlying the membrane filter. Inoculation of the clear zone with a fresh Mucor or Aspergillus spore suspension does not result in hyphal growth. Instead, germinating spores show aberrant and aborted hyphae. The fungal inhibitor shows cross-reactivity between Mucor and Aspergillus, is resistant to pronase (10 mg/mL) but not chloroform inactivation, and passes through dialysis tubing with a molecular weight cutoff of 3500.

Mucoid encapsulated Enterococcus faecalis: an emerging morphotype isolated from patients with urinary tract infections.

Three strains of encapsulated Enterococcus faecalis, which produced highly mucoid coalescing colonies on routine bacteriologic media, were isolated from urine specimens of patients with urinary tract infection. Encapsulation could be demonstrated through India ink preparations. The occurrence of this unusual enterococcal colony morphotype, which resembles that of a Gram-negative bacterium, may delay true identification.

Fusospirochetal superinfection of pre-existing oral lesion in patients with acquired immunodeficiency syndrome.

Three patients with AIDS presented with nonbleeding, painful, fetid, oral ulcers overlaid with a grayish-black semiadherent membrane at the sites of a pre-existing lesion. These lesions persisted despite treatment directed toward the primary etiology (cytomegalovirus, Kaposi's sarcoma). Gram- and Giemsa-stained smears of teased membrane fragments revealed an impressive bacterial flora with fusiforms and Borrelia-type spirochetes. Prompt treatment with penicillin brought amelioration of symptoms and sloughing of the overlaying membrane.

Yersinia enterocolitica: the charisma continues.

Yersinia enterocolitica, a gram-negative coccobacillus, comprises a heterogeneous group of bacterial strains recovered from animal and environmental reservoirs. The majority of human pathogenic strains are found among distinct serogroups (e.g. O:3, O:5,27, O:8, O:9) and contain both chromosome- and plasmid (60 to 75 kb)-mediated virulence factors that are absent in "avirulent" strains. While Y. enterocolitica is primarily a gastrointestinal tract pathogen, it may produce extraintestinal infections in hosts with underlying predisposing factors. Postinfection sequelae include arthritis and erythema nodosum, which are seen mainly in Europe among patients with serogroups O:3 and O:9 infection and HLA-B27 antigen. Y. enterocolitica is acquired through the oral route and is epidemiologically linked to porcine sources. Bacteremia is prominent in the setting of immunosuppression or in patients with iron overload or those being treated with desferrioxamine. metastatic foci following bacteremia are common and often involve the liver and spleen. Of particular concern is blood transfusion-related bacteremia. Evidence has accumulated substantiating the role of Y. enterocolitica as a food-borne pathogen that has caused six major outbreaks in the United States. The diagnosis of Y. enterocolitica gastroenteritis is best achieved through isolation of the bacterium on routine or selective bacteriologic media. When necessary, serogrouping, biogrouping, and assessment for plasmid-encoded virulence traits may aid in distinguishing virulent from "avirulent" strains. Epidemiologically, outside of identified food-borne outbreaks, the source (reservoir) of Y. enterocolitica in sporadic cases is speculative. Therefore, prevention and control measures are difficult to institute.

Persistent diarrhea caused by Isospora belli: therapeutic response to pyrimethamine and sulfadiazine.

A 54-year-old human immunodeficiency virus (HIV)-positive homosexual man developed overwhelming watery diarrhea and marked weight loss over a 3-week period. Although Entamoeba histolytica and other nonpathogenic enteric protozoa were observed along with Isospora belli in this patient's stool specimens, they were promptly eradicated after metronidazole (flagyl) treatment. The presence of I. belli oocysts in various stages of development in the stool and clinical symptoms related to Isospora infection persisted for 10 more months despite treatment with combined chemotherapeutic agents. Clinical and parasitiological resolution was ultimately achieved through an 8-week course of pyrimethamine and sulfadiazine.

Haemophilus parainfluenzae biliary tract infection: rationale for an ascending route of infection from the gastrointestinal tract.

Haemophilus parainfluenzae was isolated from a bile specimen of a 56-year-old patient with elevated liver enzymes and chronic cholecystitis. Several factors contributing to nonbacteremic H. parainfluenzae infection of the biliary tract include (i) the not infrequent occurrence of H. parainfluenzae in stool specimens, (ii) the presence of an outer membrane protein similar to those found in enteric bacteria which facilitates adherence to the colonic mucosa, and (iii) an adequate supply of V factor (nicotinamide adenine dinucleotide) supplied from bile and the local flora, which is necessary for H. parainfluenzae's growth. Because H. parainfluenzae rarely occurs in the biliary tract, direct cultivation of bile specimens on chocolate agar seems unwarranted. However, bile specimens showing a gram-negative coccobacillus on a Gram-stained smear that fails to grow on routine media should be subcultured on chocolate agar.

Capnocytophaga ochracea chronic blepharoconjunctivitis.

A 70-year-old woman presented with a 10-month history of chronic blepharoconjunctivitis that had been unresponsive to multiple methods of treatment. The patient was not immunocompromised and had no history of corneal disease, ocular trauma, or lacrimal duct obstruction. Gram and Giemsa staining of conjunctival smears resulted in visualization of slender, fusiform bacilli. Culture of conjunctival scrapings led to the recovery of a fastidious isolate identified as Capnocytophaga ochracea. The same microorganism was also recovered from cultures of the patient's gingiva. The blepharoconjunctivitis responded well to treatment with fortified cefazolin eye drops. Awareness of this easily overlooked bacterial species should prompt the use of smear and cultural techniques.

Rapid diagnosis of ocular herpes simplex infections.

BACKGROUND: The Surecell herpes (HSV) test kit is a test for detecting the presence of herpes simplex viral antigen by means of a monoclonal antibody based immunoassay. The test has proved to be highly sensitive and specific in diagnosing genital, oral, and dermatological herpes infections. METHODS: In this study, samples from patients with ocular keratitis were evaluated by tissue cultures and the Surecell test. The eyes of New Zealand rabbits were then inoculated with HSV type 1 acute keratitis, acute Staphylococcus keratitis, and HSV type 1 postkeratitis (healed corneas). Tear film samples collected from each eye with a cotton swab were evaluated by routine culture (A-549 monolayers) and by the Surecell test with and without prior placement of the swab in Hank's medium. RESULTS: The Surecell system had a 70% sensitivity and a 100% specificity in the detection of HSV antigen in ocular infections, and was shown to be a quick, efficient, and accurate method of testing for HSV antigen in humans. CONCLUSION: These results from humans and rabbits indicate that the Surecell test, which requires no special equipment, can be a useful in office adjunct in the clinical diagnosis of ocular herpes simplex.

Listeria monocytogenes infections: laboratory investigation of an unexpected increase in incidence.

Listeria monocytogenes is a facultative intracellular pathogen causing mainly meningitis and septicemia in immunocompromised hosts. From July 1988 through December 1989, 16 patients at The Mount Sinai Hospital were diagnosed as having listeriosis shortly after admission, 14 within a one-year period (July 1988-July 1989). Because this incidence was almost double the incidence in previous years (< 8 annually), an epidemiologic and microbiologic investigation was undertaken to determine a potential route of acquisition of L. monocytogenes. On the basis of plasmid profile, bacteriocin (enterocin) susceptibility pattern, and serotype, no single epidemic strain could be identified. Although direct evidence was lacking, we concluded that our patients may have acquired L. monocytogenes through transient contamination of food.

Difficulties encountered in identification of a nutritionally deficient streptococcus on the basis of its failure to revert to streptococcal morphology.

Difficulties were encountered in the recognition of a nutritionally deficient streptococcus which continued to display aberrant morphologic forms (especially bulbous swellings and filament formation) despite provision of growth factors. With isolates displaying diverse morphologic entities not characteristic of a given species, e.g., Streptobacillus moniliformis or Erysipelothrix rhusiopathiae, nutritionally deficient streptococci should be considered.