[The role of coagulase negative staphylococci in mixed infections: association testing as an in vitro model]. / Die Rolle coagulasenegativer Staphylokokken in Mischinfektionen: Assoziationstestungen als in-vitro-Modell.

Infections due to coagulase negative staphylococci (CNS) are of growing concern mainly in patients hospitalized in intensive care units (ICU). The ability of CNS to adhere and to grow on plastic devices and resistance to many antibiotics, including oxacillin, contributes to their pathogenicity. Using the computer assisted system of the Medical Microbiology Department, the incidences of different pathogens and the coincidence of CNS with other bacteria were evaluated in a surgical department. Staphylococcus aureus revealed to be the predominant pathogen; however, CNS showed an increasing incidence in wound specimens and blood cultures of patients on the ICU. Coincidence of CNS with S. aureus and the nine most frequent species of gram negative bacteria could be shown in 6%. To investigate the influence of beta-lactamases produced by CNS in mixed infections, association experiments were performed. Association means a controlled growth of two or even more bacteria in a susceptibility testing system, either a broth dilution method or an automated broth disk elution method (Cobas Bact). The association experiments showed a significant increase of amoxicillin MIC's of the pathogen associated with CNS. Addition of clavulanic acid restored activity of amoxicillin. It could be shown that in mixed infections CNS may contribute to the failure of antibiotic regimens by production of beta-lactamases.

Autoantibodies against human beta interferon following treatment with interferon.

Recently we reported the appearance of human beta interferon (HuIFN-beta) neutralizing antibodies in a patient with a nasopharyngeal carcinoma treated successfully with a preparation of HuIFN-beta. This was the first report presenting evidence for antigenicity of IFN in an homologous system. In the present report we asked whether the unusual appearance of antibodies was due to a genetic defect of the patient's cells to produce HuIFN-beta or whether the patient's cells produce an antigenically different variant of HuIFN-beta. We demonstrate that a fibroblast cell strain established from this patient produces HuIFN-beta which does not from a serological standpoint react differently from the HuIFN-beta preparation administered. The conclusion is drawn that the antibodies against therapeutic HuIFN-beta are reacting like autoantibodies with the patient's own HuIFN-beta.

Laparoscopic fenestration of a lymphocele following combined pancreas-kidney transplantation.

The development of a lymphocele is an uncommon but well-known complication following a kidney transplantation. In case of recurrence after puncture and aspiration, a laparoscopic procedure seems to be the treatment of choice. For the preoperative workup ultrasound is essential; CT scan is to be favored if available. A large fenestration is easy to perform laparoscopically and thus the lymphocele is drained into the abdominal cavity. Because of the immunosuppressive treatment, adhesions hindering a laparoscopic approach are unusual. The conclusion is that surgeons trained in laparoscopic techniques have an important role in these infrequent abdominal problems.

Cell-mediated cytotoxicity in hepatitis A virus infection.

We studied cell-mediated cytotoxicity to hepatitis A virus-infected cells in seven patients with acute type A hepatitis and two controls. Skin fibroblast cultures obtained from the skin biopsies of seven patients after acute hepatitis A virus infection and from two persons without history of current or past hepatitis A virus infection were inoculated with hepatitis A virus. Infection of fibroblast cultures always resulted in an inapparent, persistent infection with production and release of infectious hepatitis A virus. Peripheral blood lymphocytes were collected from the same patients at different times after onset of icterus and were stored in liquid nitrogen. Cytolytic activity of peripheral blood lymphocytes was determined by a microcytotoxicity assay using autologous 51Cr-labeled hepatitis A virus-infected and uninfected target cells. Cytotoxic peripheral blood lymphocytes capable of lysing autologous hepatitis A virus-infected skin fibroblasts were detected in all patients with hepatitis A but were not demonstrable in the controls without antibodies against hepatitis A virus. The clinical course of the hepatitis A virus infection was normal in five patients; and in these patients, cytolytic activity of peripheral blood lymphocytes against hepatitis A virus-infected autologous targets peaked 2 to 3 weeks after onset of icterus. A clinically protracted form of the disease with persistent elevation of aminotransferases for at least 5 months after onset was present in two patients. In these cases, the highest cytolytic activity was demonstrated in peripheral blood lymphocytes collected 8 to 12 weeks after onset of icterus.(ABSTRACT TRUNCATED AT 250 WORDS)