Prevention of biofilm formation by quorum quenching.

Quorum sensing (QS) is a mechanism that enables microbial communication. It is based on the constant secretion of signaling molecules to the environment. The main role of QS is the regulation of vital processes in the cell such as virulence factor production or biofilm formation. Due to still growing bacterial resistance to antibiotics that have been overused, it is necessary to search for alternative antimicrobial therapies. One of them is quorum quenching (QQ) that disrupts microbial communication. QQ-driving molecules can decrease or even completely inhibit the production of virulence factors (including biofilm formation). There are few QQ strategies that comprise the use of the structural analogues of QS receptor autoinductors (AI). They may be found in nature or be designed and synthesized via chemical engineering. Many of the characterized QQ molecules are enzymes with the ability to degrade signaling molecules. They can also impede cellular signaling cascades. There are different techniques used for testing QS/QQ, including chromatography-mass spectroscopy, bioluminescence, chemiluminescence, fluorescence, electrochemistry, and colorimetry. They all enable qualitative and quantitative measurements of QS/QQ molecules. This article gathers the information about the mechanisms of QS and QQ, and their effect on microbial biofilm formation. Basic methods used to study QS/QQ, as well as the medical and biotechnological applications of QQ, are also described. Basis research methods are also described as well as medical and biotechnological application.

HLA-B27M1M2 and high immune responsiveness to Shigella flexneri in post-dysenteric arthritis.

The heterogeneous HLA-B27 antigen is closely associated with post-infectious or reactive arthritis (ReA) and is comprised of two serologically defined variants: B27M1+M2+ and B27M1+M2-. An outbreak of dysentery (n = 120) caused by a Shigella flexneri 2a strain, which possessed cell envelope antigens with epitopes resembling B27M2, resulted in five B27M1+M2+ patients with ReA. The remaining seven B27M1+M2+, one B27M1+M2- and all but three B27-negative patients remained free of joint symptoms; the latter three displayed arthralgia. IgM, IgG and IgA serum titers were statistically raised in all patient groups, but were exceptionally and persistently high in the B27M1+M2+ patients with ReA, especially IgA, as determined in acute-phase sera and sera sampled 1 year after dysentery. B27M1+M2+ thus appears to be a marker for a subset of disease, characterized by a high immune response. It is concluded that the B27M2 epitope is not unequivocally disease-related to Shigella ReA, that B27M1+M2+ is not likely to be the only immune-response-regulating gene involved in this form of ReA and that cross-reactivity between bacterial antigenic epitopes and B27 can only be part of a multifactorial process leading to ReA and in itself not sufficient to produce ReA. The intensity of the immune response appears to be another important factor.

Biosimilar granulocyte colony-stimulating factor is effective in reducing the duration of neutropenia after autologous peripheral blood stem cell transplantation.

BACKGROUND: Autologous peripheral blood stem cell transplantation (APBSCT) is the standard of therapy for patients with multiple myeloma and refractory Hodgkin's and non-Hodgkin's lymphomas. Granulocyte colony-stimulating factor (G-CSF) is widely used to accelerate hematopoietic recovery after transplantation and to reduce the morbidity and mortality associated with prolonged neutropenia. Biosimilar G-CSF is approved for the same indications as the originator G-CSF. This is one of the first reported uses of a biosimilar G-CSF for neutrophil recovery after APBSCT. METHODS: A total of 23 consecutive patients with hematological malignancy (multiple myeloma, Hodgkin's and non-Hodgkin's lymphomas, and acute myelogenous leukemia) were recruited at the Department of Haematooncology and Bone Marrow Transplantation at the Medical University of Lublin. Patients (12 men and 11 women; median age, 47 ± 13 years) received biosimilar G-CSF (Zarzio, Sandoz Biopharmaceuticals) after myeloablative chemotherapy (primarily BiCnU, etoposide, cytarabine, and melphalan or melphalan 140/200 mg/m(2)) followed by PBSCT. The median number of transplanted CD34+ cells was 4.2 ± 0.8 × 10(6)/kg body wt. G-CSF therapy was started when absolute neutrophil count (ANC) was <0.5 × 10(9)/L and was continued until ANC reached >1.5 × 10(9)/L for 3 consecutive days. Hematopoietic recovery parameters were compared with those in the control group, which consisted of 23 consecutive patients transplanted in the period before the biosimilar G-CSF group and receiving originator G-CSF (Neupogen, Amgen). RESULTS: The mean duration of treatment with biosimilar and originator G-CSF was 14.4 ± 5.1 and 18.6 ± 11.5 days, respectively (P = .43). The adverse event profile was comparable between the biosimilar G-CSF and originator G-CSF groups, with similar occurrence of neutropenic fever (5 versus 6 patients) and bone pain (7 patients in each group). One patient in the biosimilar group had neutropenic enterocolitis and sepsis. There was no case of death in either group. Granulocyte recovery in the study group was as follows: mean days to ANC >0.5 × 10(9)/L was 13.0 ± 4.0 days; to ANC >1.5 × 10(9)/L, 13.6 ± 4.5 days; and to ANC >1.5 × 10(9)/L, 14.0 ± 4.7 days. Mean duration until platelet recovery >20 × 10(9)/L was 16.1 ± 4.4 days. There were no statistically significant differences between the biosimilar and originator G-CSF groups in hematopoietic recovery parameters. CONCLUSIONS: Biosimilar G-CSF is safe and effective in reducing the duration of neutropenia in patients undergoing myeloablative therapy followed by APBSCT and probably in cost savings in transplantation budgets.

Serum IgA to enterobacteria in ankylosing spondylitis.

The aetiology of ankylosing spondylitis (AS) may involve certain enterobacteria. It is therefore interesting that serum polymeric IgA, a precursor of secretory IgA, was statistically elevated in active AS (n = 35) and that levels were comparable to those found in yersiniosis (n = 12); this might indicate antigenic stimulation by bacteria which are present in the intestines of AS patients. However, specific serum IgA to the incriminated enterobacteria Klebsiella, Shigella and Yersinia, as determined by ELISA, was not raised in the above AS patients. Nor were these titres raised in patients with idiopathic reactive arthritis (n = 21). In contrast, yersiniosis (n = 12) and shigellosis (n = 96) patients displayed marked increases in specific serum IgA titres to the respective infectants. It is proposed that AS may involve a set of enterobacteria rather than a few suspected species. Thus, despite the lack of raised group averages, screening of individual patients for specific IgA to several indicated bacteria might disclose whether or not raised serum IgA is related to enterobacterial activity. Apart from this, the above supports other reports indicating that serum IgA may be a useful parameter to assist in monitoring of disease activity in AS. Finally, it is suggested that study of a homogeneous group of reactive arthritis patients might facilitate aetiological research of seronegative arthropathies such as AS.