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Biomedical subjects

G W Procop

Publications and source records attributed to G W Procop.

At least 19 recordsLinked to original sources

Multicenter comparison of the VITEK 2 yeast susceptibility test with the CLSI broth microdilution reference method for testing fluconazole against Candida spp.

A fully automated commercial antifungal susceptibility test system (VITEK 2 yeast susceptibility test; bioMerieux, Inc., Hazelwood, Mo.) was compared in three different laboratories with Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (BMD) method by testing two quality control strains and a total of 426 isolates of Candida spp. (103 to 135 clinical isolates in each laboratory plus 80 challenge isolates in one laboratory) against fluconazole. Reference BMD MIC endpoints were established after 24 and 48 h of incubation. VITEK 2 endpoints were determined spectrophotometrically after 10 to 26 h of incubation (mean, 13 h). Excellent essential agreement (within two dilutions) between the VITEK 2 and the 24- and 48-h BMD MICs was observed. The overall agreement values were 97.9 and 93.7%, respectively. Both intra- and interlaboratory agreement was 100%. The overall categorical agreement between VITEK 2 and BMD was 97.2% at the 24-h BMD time point and 88.3% at the 48-h BMD time point. Decreased categorical agreement at 48 h was attributed to trailing growth observed with Candida glabrata. The VITEK 2 system reliably detected fluconazole resistance among Candida spp. and demonstrated excellent quantitative and qualitative agreement with the reference BMD method.

Antifungal Agents↗

Use of partial 16S rRNA gene sequencing for identification of Legionella pneumophila and non-pneumophila Legionella spp.

We examined 49 Legionella species, 26 L. pneumophila and 23 non-pneumophila Legionella spp., using partial 16S rRNA gene sequencing. This approach accurately identified all the L. pneumophila isolates, characterized all non-pneumophila Legionella isolates as such within this genus, and classified most (20/23; 87%) of the non-pneumophila Legionella isolates to the species level.

Bacterial Typing Techniques↗

Multicenter evaluation of a Candida albicans peptide nucleic acid fluorescent in situ hybridization probe for characterization of yeast isolates from blood cultures.

We evaluated aliquots from 244 clinical blood culture bottles that demonstrated yeasts on Gram stain using a Candida albicans peptide nucleic acid (PNA) fluorescent in situ hybridization (FISH) probe. The sensitivity, specificity, positive predictive value, and negative predictive value of the C. albicans PNA FISH test in this study were 99%, 100%, 100%, and 99.3%, respectively.

Blood↗

Simultaneous detection of Staphylococcus aureus and coagulase-negative staphylococci in positive blood cultures by real-time PCR with two fluorescence resonance energy transfer probe sets.

A real-time PCR assay that uses two fluorescence resonance energy transfer probe sets and targets the tuf gene of staphylococci is described here. One probe set detects the Staphylococcus genus, whereas the other probe set is specific for Staphylococcus aureus. One hundred thirty-eight cultured isolates, which contained 41 isolates of staphylococci representing at least nine species, and 100 positive blood cultures that contained gram-positive cocci in clusters were tested. This assay was 100% sensitive and 100% specific for the detection of the Staphylococcus genus and of S. aureus.

Blood↗

Detection of Pneumocystis jiroveci in respiratory specimens by four staining methods.

We examined four staining methods on replicate smears of 313 respiratory specimens submitted for Pneumocystis jiroveci examination. The sensitivity and specificity of Calcofluor white stain (CW) were 73.8 and 99.6%, respectively. The sensitivity and specificity of Grocott-Gomori methenamine silver stain (GMS) were 79.4 and 99.2%, respectively. The sensitivity and specificity of Diff-Quik stain were 49.2 and 99.6%, respectively. The sensitivity and specificity of Merifluor Pneumocystis stain were 90.8 and 81.9%, respectively. Only CW and GMS had positive and negative predictive values of >90%.

Bronchoalveolar Lavage Fluid↗

In situ hybridization for the identification of filamentous fungi in tissue section.

Identification of fungi in tissue sections can be difficult because of limited biopsy tissue with only a few organisms present, or mycelial elements may be the only forms present, rendering common organism types indistinguishable from one another. In situ hybridization may assist in the rapid and accurate identification of such fungi. In this study, DNA probes were directed against the 5S or 18S ribosomal RNA sequences of three groups of fungi with a high degree of specificity for each. Two of the three, Aspergillus and Zygomycetes species, are usually seen in tissue purely in their hyphal forms. The third, Candida species is seen less commonly as predominantly mycelial elements. Probes were tested on 61 formalin-fixed, paraffin-embedded tissue specimens, each with culture-proven involvement by one of these organisms (Candida species, n = 21; Aspergillus species, n = 27; Zygomycetes, n = 13). Accuracy of both in situ hybridization (ISH) and morphology, based on the examination of Grocott methanamine silver (GMS)- and periodic acid-Schiff (PAS)-stained slides, was compared with culture. The results showed that morphologic examination (GMS and PAS) showed a slightly greater sensitivity in detecting the presence of fungi (98%) compared with in situ hybridization (95%). DNA probes, however, were more accurate in correctly identifying those organisms present. Although ISH specific probes showed 97% positive predictive value (PPV), examination of GMS-and PAS-stained slides had an 86% PPV when compared with culture-based identification methods. These results show that ISH, directed against ribosomal RNA, provides a rapid and accurate technique for the identification of mycelial fungal organisms in histologic tissue sections. Its primary use lies in the ability to accurately distinguish between organisms that have similar or identical morphologic features by light microscopy.

DNA Probes↗

Mastitis due to Mycobacterium abscessus after body piercing.

We describe a patient with granulomatous mastitis due to Mycobacterium abscessus that presented as a mass lesion and was associated with a pierced nipple. To our knowledge, this is the first reported case of mastitis due to M. abscessus and the first association of this organism with body piercing.

Adolescent↗

Infectious disease pathology.

The anatomic pathologist performs an important role in the diagnosis or exclusion of infectious diseases. The morphologic interpretation of biopsies and cytologic preparations allows for the definitive establishment or exclusion of a wide variety of diseases. Once the pathologist has determined that a disease is likely to be due to an infection and has characterized the inflammatory response, associated microorganisms or viral-associated cytopathic effects should be recorded. Although some microorganisms or their cytopathic effects may be clearly visible on routine hematoxylin and eosin-stained sections, additional histochemical stains are often needed for their complete characterization. Highly specific molecular techniques, such as immunohistochemistry, in situ hybridization, and nucleic acid amplification, may be needed in certain instances to establish the diagnosis of infection. Through appropriate morphologic diagnoses and interlaboratory communication and collaboration, the anatomic pathologist contributes greatly to the diagnosis and treatment of infectious diseases.

Animals↗

Gastrointestinal infections.

Advances in public health have reduced the risk of contracting certain enteric diseases, but many remain, and new pathogens have emerged and/or recently have been discovered. The pathogenic agents are varied and consist of a variety of bacteria and select viruses and parasites. Selected use of microbiologic assays to detect these pathogens is encouraged. When tests are ordered non-judiciously, costs rapidly accrue. The age of the patient, time of year, travel history, and clinical presentation all provide clues to the etiologic agent. Microbiologic assays should be used judiciously to confirm or exclude the likely infectious agents.

Anti-Bacterial Agents↗

Relapsing Exophiala jeanselmei phaeohyphomycosis in a lung-transplant patient.

Dematiaceous fungi are a cause of a variety of human infections, including phaeohyphomycosis, that may affect patients with solid organ or bone marrow transplants. Exophiala jeanselmei, the most common cause of the pheomycotic cyst/subcutaneous phaeohyphomycosis in the United States, has been shown to cause disease in transplant recipients. We report a lung-transplant patient with relapsing and invasive E. jeanselmei phaeohyphomycosis, who previously had a pheomycotic cyst excised and treated with oral fluconazole. The patient was subsequently treated with re-excision and an 8-month course of oral itraconazole without relapse as to date.

Adult↗

Persistence of Plasmodium falciparum in the placenta after apparently effective quinidine/clindamycin therapy.

The persistence of Plasmodium falciparum in the placenta after apparently adequate therapy with quinine has been described. We describe this phenomenon in the placenta of a 19-year-old woman with falciparum malaria, who was treated with a combination of quinidine and clindamycin. Although this therapy was effective and diminished her peripheral blood parasitemia from 3% at presentation to almost undetectable at the time of delivery, vast numbers of P. falciparum-infected erythrocytes were present in the maternal sinusoids of the placenta. This sequestration of infected erythrocytes produced a local parasitemia in the placenta of 70% to 80%. Additionally, rare Plasmodium-infected erythrocytes were also seen in the fetal blood of the placenta. We review malaria in pregnancy, parasitic involvement of the placenta and emphasize that Plasmodium-infected erythrocytes may persist in the placenta even after clearance of parasites from the peripheral blood.

Adult↗

Rahnella aquatilis bacteremia in a patient with relapsed acute lymphoblastic leukemia.

Rahnella aquatilis infections are rare. We report the case of a 46-y-old African-American male with relapsed acute lymphoblastic leukemia who had R. aquatilis bacteremia after beginning reinduction chemotherapy. He was treated for 4 weeks with piperacillin-tazobactam and gentamicin. He recovered from the infection and had an allogenic bone marrow transplant a month later.

Bacteremia↗

Evaluation of ColorPAC Giardia/Cryptosporidium rapid assay and ProSpecT Giardia/Cryptosporidium microplate assay for detection of Giardia and Cryptosporidium in fecal specimens.

Detection of Giardia and Cryptosporidium in clinical stool specimens using the ColorPAC and ProSpecT enzyme immunoassays revealed 98.7% agreement for Giardia detection and 98.1% agreement for Cryptosporidium detection. Sensitivities were uniformly 100%. The specificities of the ColorPAC immunoassay for Giardia and Cryptosporidium detection were 100 and 99.5%, respectively, and those for the ProSpecT assay were 98.4 and 98.6%, respectively. The false-positive reactions with the ProSpecT assay occurred with specimens that were grossly bloody.

Animals↗

Case of synovitis potentially caused by Dolosigranulum pigrum.

We report a case of synovitis in a 64-year-old man who developed the infection while on steroid therapy for rheumatoid arthritis. Dolosigranulum pigrum, a gram-positive catalase-negative coccus, was isolated from two sets of blood cultures prior to antibiotic therapy. The patient was treated with 4 weeks of appropriate antibiotics, and the synovial inflammation resolved. Although synovial aspirates were never positive for any bacteria or fungi, the timing of positive blood cultures and absence of other pathogens suggest the possible etiology as D. pigrum.

Blood↗

Gonorrhea in the HIV era: a reversal in trends among men who have sex with men.

OBJECTIVES: Gonorrhea cases among men who have sex with men (MSM) declined in the early years of the HIV epidemic. We evaluated more recent trends in gonorrhea among MSM through the Centers for Disease Control and Prevention's Gonococcal Isolate Surveillance Project. METHODS: Isolates and case information were collected from 29 US sexually transmitted disease (STD) clinics. Gonococcal urethritis cases among MSM were compared with those among heterosexual men, and cases among MSM in 1995 to 1999 were compared with earlier MSM cases. RESULTS: Of 34,942 cases, the proportion represented by MSM increased from 4.5% in 1992 to 13.2% in 1999 (P < .001). Compared with heterosexuals, MSM were older, more often White, and more often had had gonorrhea previously, although fewer had had gonorrhea in the past year. MSM with gonorrhea in 1995 to 1999 were slightly older than those with gonorrhea in 1992 to 1994, and a higher proportion had had gonorrhea in the past year. CONCLUSIONS: MSM account for an increasing proportion of gonococcal urethritis cases in STD clinics. Given recent evidence that gonorrhea may facilitate HIV transmission, these trends demand increased attention to safe sexual behaviors and reducing STDs among MSM.

Adult↗

Histologic features of zygomycosis: emphasis on perineural invasion and fungal morphology.

OBJECTIVE: Invasive zygomycosis is rapidly progressive and is associated with angioinvasion and infarction. Invasive disease requires emergent surgical and medical intervention. Because it is important for surgical pathologists to recognize these fungi and their preferential sites of growth, the objective of this article is to describe the fungal morphology and histopathologic findings in biopsies from patients with zygomycotic disease, with emphasis on preferential sites of fungal growth. DESIGN: Medical record and histologic review identified 20 patients with zygomycosis. Inclusion criteria included the presence of typical ribbonlike hyphae and positive culture, a clinical history of invasive zygomycosis, or both. The histologic features of disease and the fungal morphology were assessed. RESULTS: Fungus ball (15%), rhinocerebral (55%), and pulmonary (30%) disease were the types of disease represented. The inflammatory responses were predominantly neutrophilic (50%), predominantly granulomatous (5%), pyogranulomatous (25%), or absent (20%). Invasive disease was characterized by prominent infarcts (94%), angioinvasion (100%), and, surprisingly, prominent perineural invasion (90%) in biopsies that contained nerves for evaluation. At least rare hyphal septa were always seen (100%), and most branches (95%) varied from 45 degrees to 90 degrees. CONCLUSIONS: As known to mycologists, zygomycetes are pauciseptate, rather than aseptate, molds. Therefore, the presence of an occasional septum is expected. Perineural invasion is a common finding in invasive zygomycosis, as are angioinvasion and infarcts. Therefore, prior to excluding the presence of these fungi in biopsies suspected to contain zygomycetes, the perineural space should be carefully examined.

Aspergillosis↗