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Cryptosporidium Infection and CD4 Counts

Excerpt Cryptosporidiumis a coccidian parasite that infects the gastrointestinal tract in humans and can cause severe enteritis and malabsorption. Cryptosporidiosis is selflimited in immunocompeten...

Biliary Tract Obstruction in the Acquired Immunodeficiency Syndrome

Three patients with the acquired immunodeficiency syndrome had biliary obstruction resulting from benign strictures of the biliary tract. Stenosis of the distal common bile duct with differing degrees of irregularity of the smaller intrahepatic and extrahepatic ducts was seen in association with either cryptosporidial or cytomegaloviral infection of the biliary tree. We review cytomegaloviral and cryptosporidial infections of the biliary system, as well as possible relationships with idiopathic primary sclerosing cholangitis. Stenotic biliary tract disease appears to be yet another complication of the acquired immunodeficiency syndrome.

Cryptosporidiosis in Homosexual Men

Between April 1982 and June 1983, cryptosporidiosis was diagnosed in six homosexual men. Four patients with the acquired immunodeficiency syndrome had lymphopenia, cutaneous anergy, and profoundly impaired cellular immunity; their cryptosporidiosis was severe, unremitting, and refractory to all therapy. Two patients without other opportunistic infections or Kaposis sarcoma had moderately impaired cellular immunity but not lymphopenia or anergy; their enteric illness was self-limited. Cryptosporidium recently had been recognized as a human pathogen that is transmitted through fecal-oral contamination. The severity of human cryptosporidiosis appears to be determined primarily by immunocompetence of the patient. These six homosexual men, with different degrees of immunologic impairment, had two clinically divergent forms of cryptosporidiosis. Their cases raise questions about human transmission of Cryptosporidium and the prognostic significance of this disease in patients who are at high risk for developing the acquired immunodeficiency syndrome.

Paromomycin: No More Effective than Placebo for Treatment of Cryptosporidiosis in Patients with Advanced Human Immunodeficiency Virus Infection

To evaluate the efficacy of paromomycin for the treatment of symptomatic cryptosporidial enteritis in human immunodeficiency virus-infected adults, we conducted a prospective, randomized, double-blind, placebo-controlled trial before the widespread introduction of highly active antiretroviral therapy (HAART). Seven units under the auspices of the AIDS Clinical Trials Group enrolled 35 adults with CD4 cell counts of < or = 150/mm(3). Initially, 17 patients received paromomycin (500 mg 4 times daily) and 18 received matching placebo for 21 days. Then all patients received paromomycin (500 mg q.i.d.) for an additional 21 days. Clinical definitions of response were measured by an average number of bowel movements per day in association with concurrent need for antidiarrheal agents that was lower than that before study entry. There was no treatment response during the placebo-controlled phase of the study according to protocol-defined criteria (P=.88). Three paromomycin recipients (17.6%) versus 2 placebo recipients (14.3%) responded completely. Rates of combined partial and complete responses in the paromomycin arm (8 out of 17, 47.1%) and the placebo arm (5 out of 14, 35.7%) of the study were also similar (P=.72). The clinical course of cryptosporidiosis was quite variable. Paromomycin was not shown to be more effective than placebo for the treatment of symptomatic cryptosporidial enteritis. However, inadequate statistical power prevents definitive rejection of the usefulness of paromomycin as therapy for this infection.

Characterization of Encephalitozoon (Septata) intestinalis isolates cultured from nasal mucosa and bronchoalveolar lavage fluids of two AIDS patients

ABSTRACT. Microsporidia are obligate intracellular protozoan parasites that can cause opportunistic infections in AIDS patients. Species from five genera of microsporidia are presently known to infect man. One species, Septata intestinalis originally was detected in stool specimens of individuals with chronic diarrhea and subsequently was found to disseminate to the kidneys, lungs, and nasal sinuses. This organism has since been reclassified as Encephalitozoon and in this study, we report the culture of Encephalitozoon intestinalis from a bronchoalveolar lavage specimen and a nasal mucus aspirate of two AIDS patients living in the USA. The bronchoalveolar and nasal microsporidian isolates grew in several continuous cell lines including RK‐13, MDCK, HT‐29, Caco‐2, Vero, and 1047. Transmission electron microscopy of the clinical and cell culture specimens revealed that the new isolates appeared to be E. intestinalis based on morphology and growth of organisms in septated membrane‐bound parasitophorous vacuoles. The new E. intestinalis isolates were characterized and compared with the first isolated E. intestinalis that was cultured from stool to confirm their identity and to determine if there existed any minor differences, as seen in the closely related Encephalitozoon cuniculi strains. By the methods of sodium dodecyl sulfate‐polyacrylamide gel electrophoresis staining for proteins and carbohydrates, Western blot immunodetection, and polymerase chain reaction‐based methods with restriction endonuclease digestion, double‐stranded DNA heteroduplex mobility shift analysis, and DNA sequencing of the ribosomal DNA intergenic spacer region, the new isolates were identical to each other and to the reference isolate of E. intestinalis. In addition, with any of these methods, the E. intestinalis organisms could be distinguished from the three E. cuniculi strains, Encephalitozoon hellem, and Vittaforma corneae, which is important for diagnostics, therapeutic strategies, and epidemiology.

Prophylaxis Strategies for Solid-Organ Transplantation

In addition to the net state of immunosuppression, the risk of infection after transplantation is largely determined by the transplant recipients epidemiologic exposures. Potential sources of infection in the transplant recipient include the environment and the recipients endogenous flora. This article presents aspects of prevention of infection after solid-organ transplantation such as avoidance of epidemiologic exposures, antibacterial prophylaxis, prophylaxis for tuberculin-positive transplant recipients, and prophylaxis against infections with Pneumocystis carinii and Toxoplasma gondii.

Emergence of carbapenem-resistant Enterobacteriaceae as causes of bloodstream infections in patients with hematologic malignancies

Abstract Carbapenem-resistant Enterobacteriaceae (CRE) are increasingly prevalent pathogens. However, little is known about their emergence in patients with hematologic malignancies. We identified 18 patients with hematologic malignancies over 3.5 years who developed bloodstream infections (BSIs) caused by CRE. Fourteen BSIs were caused by Klebsiella pneumoniae, three by Enterobacter cloacae, and one was polymicrobial. Initial empirical antimicrobial therapy was active in two patients (11%), and a median of 55 h elapsed between culture collection and receipt of an active agent. Ten patients (56%) died, including nine (69%) of 13 neutropenic patients, with a median of 4 days from culture collection until death. CRE isolates were analyzed for carbapenemase production, β-lactamase genes and outer membrane porin deletions and characterized by multilocus sequence typing and pulsed-field gel electrophoresis (PFGE). Carbapenem resistance mechanisms included Klebsiella pneumoniae carbapenemase production and CTX-M-15 production with an absent outer membrane porin protein. No isolate had ≥95% homology on PFGE, indicating a heterogeneous, non-outbreak population of isolates. CRE BSIs are emerging in patients with hematologic malignancies and are associated with ineffective initial empirical therapy, long delays in administration of active antimicrobials and high mortality rates. New diagnostic, therapeutic and preventive strategies for CRE infections in this vulnerable population are needed.

AGENTS OF DIARRHEA

Diarrhea is a common problem for AIDS patients, and is chronic and debilitating. A thorough evaluation will reveal a pathogen in the majority of patients, and the organisms most frequently identified in AIDS patients with chronic diarrhea are Cryptosporidium, microsporidia, and Mycobacterium avium complex. Bacterial pathogens are more common in AIDS patients than in the general population and may present in different ways from infections in immunocompetent hosts. Other pathogens, including Cryptosporidium and microsporidia, are difficult to diagnose and have no effective therapy. Moreover, enteric viruses and HIV itself may contribute to the diarrhea. In addition to microbes, other factors such as medication, immune dysregulation, automatic dysfunction, and nutritional supplementation play a substantial role in diarrhea of AIDS patients.

Epidemiology and outcomes of invasive fungal infections in allogeneic haematopoietic stem cell transplant recipients in the era of antifungal prophylaxis: a single-centre study with focus on emerging pathogens.

With increased use of expanded‐spectrum triazoles for antifungal prophylaxis, the epidemiology of invasive fungal infections (IFIs) after allogeneic haematopoietic stem cell transplantation (HSCT) continues to evolve. To define the contemporary epidemiology of IFIs in this population, we reviewed all European Organization for Research and Treatment of Cancer‐Mycoses Study Group proven and probable IFIs in adults transplanted from 2002 to 2011 and determined the incidence and risk factors for IFI and post‐IFI mortality. All patients received antifungal prophylaxis. Fifty‐three (14%) of 378 allogeneic HSCT recipients developed an IFI. There were 62 IFI episodes, of which aspergillosis (n = 31; 50%) and candidaemia (n = 15; 24%) were most common. Sixteen episodes (26%) were caused by other fungi, including Mucorales (n = 6; 10%) and the following uncommon pathogens: Trichosporon asahii, Arthrographis sp., Cladosporium sp., Geosmithia argillacea and Hormographiella aspergillata. Independent IFI risk factors were hospitalisation in an intensive care unit [ICU; odds ratio (OR) = 6.0], graft‐versus‐host disease (OR = 5.3), central venous catheter use (OR = 5.2) and hypoalbuminaemia (OR = 0.3 g−1 dl−1 increase in albumin). The 90‐day mortality rate after IFI was 57%. Non‐cytomegalovirus systemic viral co‐infection (OR = 3.5) and stay in an ICU (OR = 2.9) were independent risk factors for death. Despite antifungal prophylaxis, IFIs remain common after allogeneic HSCT and previously uncommon pathogens are emerging.

Cyclosporiasis: Clinical and Histopathologic Correlates

Although the histopathologic changes associated with Cyclospora cayetanensis infection have been previously described, the histopathology and the appearance of various life cycle stages have not been correlated with severity, stage, and duration of clinical disease. We report a prospective clinical investigation of disease characteristics and histopathologic findings in three otherwise healthy, immunocompetent patients with symptomatic C. cayetanensis infection, the duration of which ranged from 6 to 60 days. Varying degrees of gross and microscopic gastrointestinal inflammation were seen before treatment. An electron-dense phospholipid membrane/myelin-like material was variably present both before and after treatment. The greatest amount of myelin-like material was seen in the patient with prolonged disease. The results of our study suggest that inflammatory changes associated with C. cayetanensis infection may persist beyond parasite eradication. It is intriguing to speculate that the myelin-like material is a marker for persistent inflammation, but further study and confirmation are needed.