Intraoperative contamination of the suction tip in clean orthopedic surgeries in dogs and cats.

OBJECTIVE: To (1) determine suction tip (intermittent and continuous mode) contamination rate in orthopedic surgery in dogs and cats; (2) examine the effect of surgical time on contamination; and (3) report bacteria isolated. STUDY DESIGN: Clinical study. SAMPLE POPULATION: Clean orthopedic surgeries (n = 50). METHODS: Surgical procedures were assigned to 1 of 2 groups: (1) continuous (n = 25) or (2) intermittent suction (n = 25). A control suction was operated in each surgery. Samples for aerobic and anaerobic bacteriologic examination were collected from the surgical suction at 0, 20, 60 minutes, and at the end of surgery, and from the control suction at the end of the surgery only. Comparison of continuous and intermittent suction data, and the effect of surgical time on contamination rate were analyzed using a Kaplan-Meier survival analysis followed by a Cox proportional hazards model. P < .05 was considered significant. RESULTS: Aerobic contamination occurred in 22 of 50 surgical procedures and there was no anaerobic growth. There was no significant difference between continuous and intermittent suction mode groups (P = .40). Surgical time did not influence the contamination rate (P = .79). Bacterial cultures mainly revealed coagulase-negative Staphylococci, however multiresistant bacteria were isolated. CONCLUSIONS: We failed to find superiority of the intermittent operation mode of the suction tip over the continuous mode. A safe time frame before contamination of the suction tip occurs that could not be defined.

The effect of Chlamydophila pneumoniae Major Outer Membrane Protein (MOMP) on macrophage and T cell-mediated immune responses.

The Major Outer Membrane Protein (MOMP) belongs to the membrane complex of cysteine-rich proteins of Chlamydophila pneumoniae. Although MOMP can elicit strong immune responses it fails to confer long-term protection against infection in animal models. This effect has been attributed, at least in part, to an inadequate induction of protective Th1-mediated immune responses. In an effort to understand the cellular mechanisms associated to the immunomodulatory properties of MOMP we studied the effect of this protein on mouse macrophages and naïve T-lymphocytes. We found that incubation of mouse macrophages with recombinant MOMP (rMOMP) results in an increased secretion of MMP-9 and a down-regulation of MHC class II, CD86 and CD40. This was accompanied by an increase in IL-10 and IFNγ but not in IL-12 secretion. rMOMP induced a down-regulation of the expression of CD69 and CD154 markers by activated CD4(+) T cells, and enhanced the secretion of IL-2 and IL-10 by these cells. Conversely, rMOMP-treated macrophages up-regulated the expression of CD69 but not CD154, inhibited the synthesis of IL-10 and up-regulated the production of IFNγ by activated CD8(+) T cells. Immunization of mice with MOMP induced the synthesis only of MOMP-specific IgG1 but no differences in cytokine profile were observed compared to controls. Our results provide new evidence on the role of MOMP in modulating T cell-mediated immune responses.