Immune reconstitution reactions in human immunodeficiency virus-negative patients: report of a case and review of the literature.

BACKGROUND: Immune reconstitution inflammatory syndrome (IRIS) is a phenomenon initially described in patients with human immunodeficiency virus. Upon initiation of combination antiretroviral therapy, recovery of cellular immunity triggers inflammation to a preexisting infection or antigen that causes paradoxical worsening of clinical disease. A similar phenomenon can occur in human immunodeficiency virus-negative patients, including pregnant women, neutropenic hosts, solid-organ or stem cell transplant recipients, and patients receiving tumor necrosis factor inhibitors. OBSERVATIONS: We report a case of leprosy unmasking and downgrading reaction after stem cell transplantation that highlights some of the challenges inherent to the diagnosis of IRIS, especially in patients without human immunodeficiency virus infection, as well as review the spectrum of previously reported cases of IRIS reactions in this population. CONCLUSIONS: The mechanism of immune reconstitution reactions is complex and variable, depending on the underlying antigen and the mechanism of immunosuppression or shift in immune status. Use of the term IRIS can aid our recognition of an important phenomenon that occurs in the setting of immunosuppression or shifts in immunity but should not deter us from thinking critically about the distinct processes that underlie this heterogeneous group of conditions.

Impact of a piperacillin-tazobactam shortage on antimicrobial prescribing and the rate of vancomycin-resistant enterococci and Clostridium difficile infections.

UNLABELLED: States in 2002 on antimicrobial prescribing and associated rates of vancomycin-resistant enterococci (VRE) and Clostridium difficile infections.Design. Retrospective chart review.Setting. University-affiliated medical center. Measurements and Main Results. Microbiologic reports, patient demographics, and antimicrobial utilization were evaluated for patients admitted 6 months before the shortage (March 1-August 31, 2001) and for 6 months during the shortage (March 1-August 31, 2002). Significant increases in usage of alternative mu-lactamase inhibitor combinations, cefepime, levofloxacin, vancomycin, clindamycin, and metronidazole were observed during the shortage; in contrast, a significant decrease in the use of ceftriaxone took place. No change in the rate of VRE infection was observed from before to during the piperacillin-tazobactam shortage. However, a paradoxical 47% decrease in the rate of C. difficile colitis was documented during the shortage. Subsequent multivariate analyses suggested the reduced use of ceftriaxone and increased use of levofloxacin, but not the reduced use of piperacillin-tazobactam, correlated with the decreased rate of C. difficile infections. CONCLUSION: The piperacillin-tazobactam shortage was associated with significant changes in antimicrobial prescribing, which resulted in a significant reduction in the rate of C. difficile but not VRE infections.

Antimicrobial therapy of gram-negative bacteremia at two university-affiliated medical centers.

PURPOSE: To describe antimicrobial prescribing practices and patient outcomes associated with the treatment of aerobic gram-negative rod bacteremia at two university-affiliated medical centers. SUBJECTS AND METHODS: All adult patients with gram-negative bacteremia (N = 326) who were at Stanford and University of California, San Francisco (UCSF) Hospitals from September 1, 1996 through August 31, 1997 were evaluated via retrospective review of medical records. RESULTS: Most patient characteristics were similar between institutions; however, patients at Stanford were more likely to have had a diagnosis of bone marrow transplantation, liver failure, or poor nutritional status, while more patients at UCSF had solid organ transplant, diabetes, pulmonary disease, or hypotension. The bacteriology was similar at both sites, with Escherichia coli the predominant pathogen (139 [43%] of 326). The majority of episodes were community acquired (67% [218/326]). Patients at Stanford were more likely to have been treated empirically with aminoglycosides (28% vs. 7%, P <0.001) and noncephalosporin beta-lactams (31% vs. 11%, P <0.001), while patients at UCSF were more likely to have received cephalosporins (62% vs. 29%, P <0.001) and fluoroquinolones (21% vs. 11%, P = 0.02). These patterns continued for definitive therapy. Overall mortality was 60 (19%) of 326. Several risk factors were associated with 14-day mortality, including severity of illness, neutropenia, diabetes mellitus, use of vasopressors, and empiric use of a noncephalosporin beta-lactam. CONCLUSION: Prescribing practices for the treatment of gram-negative bacteremia differed significantly in the two institutions despite similar patients and pathogens.