A systemic vaccine based on Escherichia coli O157:H7 bacterial ghosts (BGs) reduces the excretion of E. coli O157:H7 in calves.

Cattle are the main reservoir of enterohemorrhagic Escherichia coli O157:H7, a bacterium that, in humans, causes hemorrhagic colitis and hemolytic uremic syndrome (HUS), a life-threatening disease, especially in children and older people. Therefore, the development of vaccines preventing colonization of cattle by E. coli O157:H7 could be a main tool for an HUS control program. In the present study, we evaluated bacterial ghosts (BGs) of E. coli O157:H7 as an experimental vaccine against this pathogen. BGs are empty envelopes of Gram-negative bacteria, which retain the morphological surface make-up of their living counterparts and are produced by controlled expression of the cloned protein E, which causes loss of all the cytoplasm content. In this work, E. coli O157:H7 BGs were used for subcutaneous immunization of calves. The vaccinated animals elicited significant levels of BG-specific IgG but not IgA antibodies in serum. Low levels of IgA and IgG antibodies against BGs were detected in saliva from vaccinated animals. Following oral challenge with E. coli O157:H7, a significant reduction in both the duration and total bacterial shedding was observed in vaccinated calves compared to the nonimmunized group. We demonstrated that systemic vaccination with E. coli O157 BGs provides protection in a bovine experimental model. Further research is needed to reach a higher mucosal immune response leading to an optimal vaccine.

Cyclic neutropenia: an unusual disorder of granulopoiesis effectively treated with recombinant granulocyte colony-stimulating factor.

Cyclic neutropenia (CN) is a rare hematologic disorder characterized by regular cycling of the absolute neutrophil count and a symptom complex presenting during the neutropenic nadirs. Despite the profound cyclic neutropenia, most patients have a benign course of recurrent fever, malaise, oral ulceration, and minor skin and upper respiratory tract infections. Recurrent infections, inflammation, and ulcers can lead to significant chronic morbidity. Severe dental disease is common, pregnancy complications are increased, and overwhelming infections, bowel necrosis, and mortality, although rare, are potential sequelae. We report a 10-year-old boy with a classical presentation of CN that had remained undiagnosed for 10 years. The difficulty in diagnosing this unusual disorder is highlighted. Treatment with daily recombinant granulocyte colony-stimulating factor (rG-CSF) resulted in a complete clearing of symptoms and a significant increase in quality of life. The excellent clinical response of CN to rG-CSF, in the absence of major adverse effects, is strongly demonstrated by this case and supports rG-CSF as a first-line therapy for CN. The physiologic and adverse effects of rG-CSF use in CN and other neutropenic disorders, including potential leukemic induction, are reviewed. The need for long-term follow-up to investigate the effects of chronic hematopoietic stimulation by rG-CSF is emphasized.

Cutaneous aspergillosis and acquired immunodeficiency syndrome.

BACKGROUND: Primary cutaneous aspergillosis is an uncommon finding in patients with acquired immunodeficiency syndrome (AIDS); only 13 cases have been reported in the literature. OBSERVATIONS: We describe 11 patients with primary cutaneous aspergillosis and AIDS. There does not seem to be an age, sex, race, or human immunodeficiency virus risk factor predisposition. This is a late manifestation of AIDS; patients typically have low CD4 counts (<0.050 x 10(9)/L [<50/microL]) and other AIDS-defining illnesses. The most frequent presentation is in patients with cytomegalovirus disease and neutropenia caused by ganciclovir therapy. Lesions developed at the site of occlusive dressings for an indwelling intravenous catheter site in 10 patients. Neutrophil counts may be normal at the time of diagnosis. A minor presentation is in the patient without neutropenia as a result of traumatic inoculation. Histological findings and/or culture results are required for diagnosis. Patients develop cutaneous lesions despite prophylactic therapy with fluconazole. Lesions can be treated with excision and lifelong therapy with itraconazole. CONCLUSION: Because of the potential morbidity and mortality of cutaneous aspergillosis, a high level of suspicion and prompt institution of therapy is required.