Biomedical subjects

J R Garrison

Publications and source records attributed to J R Garrison.

4 recordsLinked to original sources

PubMed1997

Staphylococcus epidermidis graft infection is associated with locally suppressed major histocompatibility complex class II and elevated MAC-1 expression.

OBJECTIVES: To determine the local cellular immune response in a series of human patients with Staphylococcus epidermidis prosthetic graft infection and to use a murine model to investigate the response in polytef (PTFE) and in a nonslime-producing S epidermidis variant. METHODS: Externally supported Dacron and PTFE grafts, either sterile or colonized with slime (RP-62A)- or nonslime (RP-62NA)-producing S epidermidis (10(7) colony forming units/cm2) were implanted in a dorsal subcutaneous pocket of Swiss Webster mice (Taconic, Germantown, NY). The grafts were harvested at 7, 10, 14, and 28 days with local bacterial and leukocyte counts obtained. Perigraft and blood monocyte major histocompatibility complex class II (MHC-II) (immune antigen) and membrane attack complex type 1 (MAC-1) (glycoprotein) expression were analyzed by flow cytometry in the murine model and in 3 patients representing 4 Dacron graft infections. RESULTS: The human infected Dacron perigraft monocytes revealed a suppressed MHC-II and elevated MAC-1 expression, and early correlation with the murine model was seen. No notable perigraft monocyte MHC-II suppression occurred in the infected PTFE graft. The reciprocal relationship in Dacron between monocyte MAC-1 and MHC-II expression was exaggerated with the lack of slime production. Bacterial clearance was variable. Supranormal expression was observed at 1 month in sterile Dacron but not in PTFE grafts. CONCLUSIONS: Staphylococcus epidermidis infection is associated with local cellular immune suppression in Dacron but not PTFE grafts. Slime-producing S epidermidis induced a lesser cytotoxic-phagocytic response than the nonslime variant. The reduced immunologic response to slime-producing S epidermidis may explain, in part, its indolent nature and resistance to eradication.

Animals↗

PubMed1996

Predicting the need to pack early for severe intra-abdominal hemorrhage.

OBJECTIVE: To determine if the decision to pack for hemorrhage could be refined. MATERIALS AND METHODS: Seventy consecutive trauma patients for whom packing was used to control hemorrhage were studied. The patients had liver injuries, abdominal vascular injuries, and bleeding retroperitoneal hematomas. Preoperative variables were analyzed and survivors compared with nonsurvivors. RESULTS: Packing controlled hemorrhage in 37 (53%) patients. Significant differences (p < 0.05) between survivors and nonsurvivors were Injury Severity Score (29 vs. 38), initial pH (7.3 vs. 7.1), platelet count (229,000 vs. 179,000/mm3), prothrombin time (14 vs. 22 seconds), partial thromboplastin time (42 vs. 69 seconds), and duration of hypotension (50 vs. 90 minutes). Nonsurvivors received 20 units of packed red blood cells before packing compared to 13 units for survivors. CONCLUSION: Patients who suffer severe injury, hypothermia, refractory hypotension, coagulopathy, and acidosis need early packing if they are to survive. Failure to control hemorrhage is related to severity of injury and delay in the use of pack tamponade. A specific protocol that mandates packing when parameters reach a critical limit should be considered.

Abdominal Injuries↗

PubMedDate not supplied

In vitro and in vivo effects of rifampin on Staphylococcus epidermidis graft infections.

Rifampin, bound in high concentrations to prosthetic grafts, has been proposed for the treatment of vascular graft infections. The optimum antibiotic concentration and duration of treatment for infected grafts is not known. This study compared the in vitro and in vivo efficacy of varying concentrations of rifampin against three different strains of slime producing Staphylococcus epidermidis (RP62A, KC2, and KB1) bound to the knitted Dacron at high and low concentrations at 10(4) and 10(7) CFU/cm2 of prosthetic. Time kill experiments were performed at 4, 18, and 42 hr, in which each Dacron bound bacterial strain was exposed in vitro to 4X, 64X, 100X, and 1,000X minimum inhibitory concentration (MIC) of rifampin. In vitro, the Dacron bound laboratory strain RP62A was implanted subcutaneously in the backs of male Swiss-Webster mice and exposed to 4X, 100X, and 1,000X the MIC of rifampin for similar time periods. In addition, systemic vancomycin (10 mg/kg) was assessed for synergy and prevention of rifampin resistance. In vitro, all concentrations of rifampin showed near total killing (< 1 log) of all bacterial strains at low initial concentrations (10(4) CFU/cm2) but not high (10(7) CFU/cm2) to 42 hr. Importantly, resistance was shown to develop in all three strains of S. epidermidis with high initial bacterial biofilm concentrations. In vivo, rifampin concentrations between 4X MIC and 100X MIC achieved a balance between optimal killing and prevention of resistance. Systemic vancomycin slightly improved bacterial clearance but did not alter the development of rifampin resistance at high local concentrations. Caution is advised with the use of antibiotic bonded grafts because resistance may develop even with the addition of systemic antibiotics.

Animals↗

PubMedDate not supplied

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Humans↗