Ehrlichia chaffeensis in Missouri ticks.

A nested polymerase chain reaction specific for Ehrlichia chaffeensis was used to attempt to amplify DNA from extracts of 100 individual ticks collected from 13 counties in central Missouri. Seventeen of 59 Amblyomma americanum and six of 41 Dermacentor variabilis ticks exhibited the characteristic 389-basepair product. This supports the hypothesis that these tick species may be vectors of human monocytic ehrlichiosis.

Central nervous system manifestations of human ehrlichiosis.

Since 1989, we have confirmed the diagnosis of human ehrlichiosis in 57 patients. Although routine radiological studies of the central nervous system (CNS) or analyses of cerebrospinal fluid (CSF) samples were not done for these patients, primary care physicians detected symptoms or signs that prompted them to perform such studies. CSF samples were examined for 15 of the 57 patients. Findings in eight of the 15 CSF samples were abnormal, and the most common abnormalities were lymphocytic pleocytosis and elevated protein levels. A search of the English-language literature revealed 21 additional cases in which CSF examinations were performed; in 13 of these cases, CSF findings were abnormal. The most common clinical finding that predicted CSF abnormalities was a change in mental status. A total of 14 patients underwent computerized tomographic studies, and none of these studies showed abnormalities. Four (19%) of the 21 patients with CNS manifestations of ehrlichiosis and abnormal CSF findings died.

Apoptosis of gamma/delta T cells in human ehrlichiosis.

Expansion of activated T cells expressing the T-cell receptor (TCR) gamma/delta, CD45RO, and HLA-DR antigens is a prominent feature of acute infection with Ehrlichia chaffeensis in humans. The fate of these activated cells and the resolution of the gamma/delta T-cell response with return to the usual alpha/beta T-cell populations in this disease are not clearly understood. At a morphologic level, apoptotic cells are present in the peripheral blood during the acute and resolution phases of the infection. Simple culture of density gradient-separated lymphocytes from the blood of patients with acute ehrlichiosis produced cell death rapidly in the media compared to alpha/beta T cells. This loss of viability after incubation was apparently mediated by apoptosis, based on flow cytometric and morphologic analyses. The results suggest that most primed (CD45RO+) and activated (HLA-DR+) gamma/delta T cells in acute ehrlichiosis might be subject to removal from the body by programmed or apoptotic cell death.

Lymphocytosis of gamma/delta T cells in human ehrlichiosis.

The majority of T cells in peripheral blood express a T-cell receptor (TCR) comprised of alpha and beta chains. An alternate form of the TCR is comprised of gamma and delta chains. These gamma/delta T cells are associated with certain infectious lesions, and modestly elevated in peripheral blood in certain disease states. Human ehrlichiosis is characterized by hematologic abnormalities including multi-lineage cytopenias. In most cases reported, a lymphocytopenia has been present either at diagnosis, or at some time during the illness. Early in the course of antibiotic treatment (48-72 hours), the lymphocytopenia corrects itself and is rapidly followed by a lymphocytosis of T cells that express CD3, but are negative for CD4 and CD8, as well as the major form of the TCR formed by the alpha/beta heterodimer. Instead, these CD3+4-8- T cells express the gamma/delta heterodimer associated with V gamma 9 and V delta 2 chains, a population of cells usually the distinctive minority of peripheral blood T cells, but constituting the major phenotype of peripheral gamma/delta T cells.

Ehrlichiosis--a cause of prolonged fever.

Human ehrlichiosis is a recently described illness that is thought to be tick-borne. Most recognized cases of human ehrlichiosis manifest as an acute nonspecific febrile illness. The natural history of untreated symptomatic disease is largely unknown. Over a 4-year period, we identified 41 cases of human ehrlichiosis by serological testing, polymerase chain reaction analysis, or both methods. The principal finding for six of the patients was protracted fever. The duration of their fevers ranged from 17 to 51 days. At the time of presentation, all six patients had clinical features, laboratory features, or both consistent with a diagnosis of ehrlichiosis. Polymerase chain reaction analysis helped to rapidly confirm the diagnosis for four of five patients tested. The diagnosis of human ehrlichiosis should be considered for patients with prolonged fever who live in an area of endemicity.

Mediastinal histoplasmosis presenting with esophageal involvement and dysphagia: case study.

Esophageal involvement with histoplasmosis is uncommon, but has been recognized in two clinical settings. Most commonly, the esophagus becomes involved as a result of contiguous mediastinal lymphadenopathy. Such patients usually present with dysphagia secondary to midesophageal compression or stricture. The esophagus can also be involved in cases of disseminated histoplasmosis. Esophageal ulcers or nodular lesions are the usual clinical manifestations in this setting. We report a case of mediastinal histoplasmosis with esophageal narrowing and mucosal ulceration that presented with dysphagia. The diagnosis was established at thoracotomy by the histologic finding of necrotizing granulomas and a positive fungal stain. The case was successfully treated with amphotericin B. The literature on esophageal and gastrointestinal histoplasmosis is reviewed.

Human ehrlichiosis in adults after tick exposure. Diagnosis using polymerase chain reaction.

OBJECTIVE: To identify and prospectively follow patients with suspected human ehrlichiosis regarding clinical manifestations, laboratory variables, methods for confirming the diagnosis, and complications. DESIGN: Prospective case study. SETTING: University and Veterans Affairs hospital and clinics. PATIENTS: Observations in 30 adult patients with acute febrile illness or with unexplained fevers and cytopenias or abnormal liver profiles or both. MEASUREMENTS: Serial clinical examinations, hematologic profiles, liver profiles, electrolyte determinations, chest radiographs, and response to therapy; other studies appropriate for patient care. INTERVENTION: Therapy with doxycycline. RESULTS: Thirty cases of ehrlichiosis were identified between 1989 and 1992. Tick exposure was strongly associated with the illness (P = 0.0001). Symptoms were nonspecific; fever, chills, and headache predominated but many other symptoms also occurred. Fever and skin rashes with various morphologic characteristics were the most common physical findings. Laboratory investigations indicate that the hematologic, hepatic, and central nervous systems are commonly involved in human ehrlichiosis. Twenty of 23 patients (87%) tested by the polymerase chain reaction using Ehrlichia chaffeensis sequences and whole blood samples were positive for E. chaffeensis. CONCLUSIONS: The syndrome of human ehrlichiosis is not commonly recognized by physicians. Ehrlichiosis should be considered in the differential diagnosis of patients with febrile illness after known or possible tick exposure, particularly if accompanying cytopenias or abnormal liver profiles or both are present. The therapeutic response to doxycycline is prompt, and complications are uncommon in promptly treated patients. The polymerase chain reaction applied to whole blood samples is a promising test for rapid confirmation of the diagnosis within 24 to 48 hours.

Peritoneal dialysis-related peritonitis treatment recommendations. 1993 update. The Ad Hoc Advisory Committee on Peritonitis Management. International Society for Peritoneal Dialysis.

In conclusion, the recommendations provided in this document represent a distillation of various experiences, as well as data obtained from published studies. It is hoped that this compilation will provide a basis upon which future developments and advances can be made in the therapeutic approach to infectious complications of peritoneal dialysis.

Diagnosis of Campylobacter pylori infections: the "gold standard" and the alternatives.

Both direct and indirect techniques are available for the detection of gastric infections due to Campylobacter pylori. These techniques vary in their degree of efficacy, invasiveness, and convenience. They fall into five major categories, based on either the particular characteristic of the C. pylori organism or the manifestation of the C. pylori infection that they detect. The five categories include histologic examination of culture biopsy specimens, serologic examination, rapid urease tests, and carbon isotype breath tests. The observed efficacies of the techniques for detection of C. pylori are influenced by the standard with which they are compared. At present, the best candidate for the "gold standard" appears to be histologic detection by examination of multiple mucosal biopsy specimens.

Serum IgG and IgA antibody responses to Campylobacter pylori in a group of healthy asymptomatic volunteers.

Sera from 17 healthy asymptomatic volunteers were tested for presence of IgG and IgA antibodies against Campylobacter pylori and correlated with endoscopic biopsy findings. Three volunteers infected with C. pylori had the highest IgG antibody titers of the group. None of 14 C. pylori free subjects had significant IgG antibody levels. IgA antibody titers were negative in all subjects regardless of state of infection, in contrast to control sera from symptomatic C. pylori infected patients who manifested high IgA antibody levels.

Antimicrobial therapy for CAPD-associated peritonitis.

Infectious peritonitis continues to be the leading cause of morbidity in patients on continuous ambulatory peritoneal dialysis (CAPD). Optimum management of CAPD-associated peritonitis requires a concerted effort toward the establishment of the specific agent causing the episode. We have reviewed the current literature relating to the diagnosis and institution of antimicrobial therapy. Controlled comparative trials are needed to determine the efficacy of potentially less toxic therapeutic regimens for peritonitis, for definition of and treatment of exit-site infections, and timing of catheter replacement.

Activities of five new fluoroquinolones against Pseudomonas pseudomallei.

Thirty-four isolates of Pseudomonas pseudomallei were tested by a broth microdilution technique for susceptibility to amifloxacin, ciprofloxacin, enoxacin, norfloxacin, and ofloxacin. Ciprofloxacin was the most active agent tested, with an MIC for 90% of the strains tested of 8 micrograms/ml. These in vitro results suggest that the fluoroquinolones tested would not be optimal for therapy of melioidosis.

Gastritis and Campylobacter pylori in healthy, asymptomatic volunteers.

A high prevalence of histologic gastritis in asymptomatic individuals has been reported in the literature. The studies have been poorly controlled for gastritis risk factors. We evaluated 20 healthy, asymptomatic volunteers free of known risk factors for gastritis with endoscopy, mucosal biopsy, culture, and gastric pH determination. The prevalence of gastritis on histologic examination was found to be 20%. There was no relationship between the presence of macroscopic findings at endoscopy and the presence of histologic gastritis. In all instances where histologic gastritis was documented, Campylobacter pylori was observed in the gastric mucus. Mucosal tissue invasion by C pylori was not observed. The presence of gastritis and C pylori was associated with fasting hypochlorhydria. Follow-up evaluation was performed eight to 13 months after the initial endoscopic evaluation in three of the volunteers with positive test results. Persistence of C pylori and gastritis was observed. These findings suggest that histologic gastritis is common in healthy, asymptomatic individuals and is strongly associated with the presence of C pylori.

Salmonella vertebral osteomyelitis treated with cefotaxime.

The antimicrobial therapy of systemic salmonella infections is presently limited to ampicillin, chloramphenicol, and sulfamethoxazole and trimethoprim. Infrequently, alternative therapy may be necessary. We report the successful treatment of a case of Salmonella vertebral osteomyelitis with cefotaxime sodium.