No abstract

The process of continuous ambulatory peritoneal dialysis has provided a useful, relatively inexpensive, and safe alternative for patients with end-stage renal disease. Infectious peritonitis, however, has limited a more widespread acceptance of this technique. The definition of peritonitis in this patient population is not universally accepted and does not always include the laboratory support of a positive culture (or Gram stain). In part, the omission of clinical microbiological findings stems from the lack of sensitivity of earlier microbiological efforts. Peritonitis results from decreased host phagocytic efficiency with depressed phagocytosis and bactericidal capacity of peritoneal macrophages. During episodes of peritonitis, fluid movement is reversed, away from the lymphatics and peritoneal membrane and toward the cavity. As a result, bloodstream infections are rare. Most peritonitis episodes are caused by bacteria. Coagulase-negative staphylococci are the most frequently isolated organisms, usually originating from the skin flora, but a wide array of microbial species have been documented as agents of peritonitis. Clinical microbiology laboratories need to be cognizant of the diverse agents so that appropriate primary media can be used. The quantity of dialysate fluid that is prepared for culture is critical and should constitute at least 10 ml. The sensitivity of the cultural approach depends on the volume of dialysate, its pretreatment (lysis or centrifugation), the media used, and the mode of incubation. The low concentration of microorganisms in dialysate fluids accounts for negative Gram stain results. Prevention of infection in continuous ambulatory peritoneal dialysis patients is associated with the socioeconomic status of the patient, advances in equipment (catheter) technology, and, probably least important, the application of prophylactic antimicrobial agents.

The Addi-Chek (filtration; Millipore Corp., Bedford, Mass.) and BACTEC (radiometric detection of growth in culture media; Johnston Laboratories, Inc., Towgon, Md.) systems were compared with the 10-mi culture (centrifugation) method for the recovery of microorganisms from peritoneal dialysate collected from patients with clinical evidence of peritonitis and containing 2200 leukocytes per mm3. Both alternate methods were comparable, and results were not significantly different from those of the conventional 10-mi culture method. All systems were adversely affected in their capacity to recover organisms when dialysates had been collected during periods of antimicrobial therapy.

We report a case of Mycobacterium bovis BCG vertebral osteomyelitis in a 79-year-old man 2.5 years after intravesical BCG therapy for bladder cancer. The recovered isolate resembled M. tuberculosis biochemically, but resistance to pyrazinamide (PZA) rendered that diagnosis suspect. High-pressure liquid chromatographic studies confirmed the diagnosis of M. bovis BCG infection. The patient was originally started on a four-drug antituberculous regimen of isoniazid, rifampin, ethambutol, and PZA. When susceptibility studies were reported, the regimen was changed to isoniazid and rifampin for 12 months. Subsequently, the patient was transferred to a skilled nursing facility for 3 months, where he underwent intensive physical therapy. Although extravesical adverse reactions are rare, clinicians and clinical microbiologists need to be aware of the possibility of disseminated infection by M. bovis BCG in the appropriate setting of clinical history, physical examination, and laboratory investigation.

No abstract

The in vitro activity of gemifloxacin against 316 bloodstream isolates of staphylococci, pneumococci, and enterococci was compared with the activities of six fluoroquinolones and three other antimicrobial agents. Of the antimicrobial agents tested, gemifloxacin was the most potent against penicillin-intermediate and -resistant pneumococci, methicillin-susceptible and -resistant Staphylococcus epidermidis isolates, and coagulasenegative staphylococci.

No abstract

Staphylococcus simulans was identified as the etiological agent of osteomyelitis and septic arthritis in an adult male who had sustained a fracture of the fibula and syndesmosis separation which required the installation of orthopedic hardware. Identifying characteristics and antibiograms for this organism, recovered from blood, wound exudate, and deep tissue samples, were determined. Recent evidence has linked slime production (adherence to smooth surfaces) by coagulase-negative staphylococci to infections by these organisms at sites where foreign bodies had been inserted. Tests for adherence showed this S. simulans strain to be a strong slime producer. This is the first reported case of osteomyelitis and septicemia due to S. simulans.