Microbiological aspects of peritonitis associated with continuous ambulatory peritoneal dialysis

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.

Microbiology and Outcomes of Peritonitis in Northern India

“…There was a tremendous increase in the isolation rate of CONS (23.4% of total peritonitis episodes but 69.6% of all gram-positive episodes), possibly because of a better isolation technique. This is also concordant with reports from the developed world, where CONS was identified as the most common pathogen (1,(22)(23). In our earlier study, the isolation rate of CONS was low (13% of total peritonitis episodes) with an overall culture-positive rate of 63% (4).…”

Consensus Guidelines for the Prevention and Treatment of Catheter-Related Infections and Peritonitis in Pediatric Patients Receiving Peritoneal Dialysis: 2012 Update

“…Should there be any delay in either transport or processing for culture, effluent samples must be refrigerated at 4°C until processed, but blood-culture bottles should be incubated at 37°C. A delay of more than 12 hours is unacceptable and will likely generate spurious results (57,163).…”

Haemophilus influenzae: a cause of peritonitis in peritoneal dialysis

“…Relevant reasons include low concentrations of micro-organisms, intracellular survival of and surface tension between bacteria, and presence of antibiotics [1]. Another reason may be the lack of specific growth factors in the culture media.…”

“…Cultures of peritoneal fluids from patients with PD peritonitis (defined as > 100 x 10 6 /l white cells) have been reported as negative in up to 50% of all episodes [1,2]. Relevant reasons include low concentrations of micro-organisms, intracellular survival of and surface tension between bacteria, and presence of antibiotics [1].…”

“…Peritonitis, a major complication of peritoneal dialysis (PD), is usually caused by coagulase-negative staphylococci, Staphylococcus aureus and streptococci [1,2]. Although infections with Haemophilus influenzae are common in children, peritonitis due to this pathogen is rare [3][4][5].…”