Photo Credit: Narong Niamfoi
Research shows the presence of cloudy effluent in peritoneal dialysis-associated peritonitis is highly predictive of vancomycin-sensitive infections.
“Peritoneal dialysis (PD) is an effective renal replacement therapy for the treatment of end-stage renal disease,” researchers wrote in BMC Nephrology. “However, PD-associated peritonitis (PDAP) is a serious complication that is the greatest contributor to infection-related morbidity, including the risk of hospitalization, temporary or permanent transfer to hemodialysis, and mortality.”
The researchers continued that timely and effective treatment of PDAP is critical, while a “precise etiological diagnosis and early targeted antibiotic therapy are highly desirable.”
The causative organisms can be difficult to determine at the time of diagnosis. For this reason, the International Society for Peritoneal Dialysis recommends that clinicians use first-generation cephalosporin or vancomycin for gram-positive organisms and third-generation cephalosporin or aminoglycoside for gram-negative organisms, according to the study results.
“However, broad-spectrum antibiotic coverage increases the possibility of secondary infections such as fungal peritonitis episodes and potential problems (including drug interactions and the emergence of resistant strains) with fungal prophylaxis treatment,” investigators wrote.
For the study, researchers examined the association between clinical characteristics of PDAP and susceptibility to vancomycin. They also investigated the use of vancomycin monotherapy alone as an initial treatment regimen for certain patients with PDAP to avoid unnecessary antibiotic exposure and secondary infection.
The retrospective study of 109 patients with culture-positive PDAP divided patients into two groups: those with cloudy effluent and no other symptoms versus those with cloudy effluent and abdominal pain and/or fever. They compared effluent bacterial cultures and antibiotic sensitivity test results between the groups, then used logistic regression analysis to identify factors linked with vancomycin susceptibility.
Classifying Different PDAP Infections
Researchers examined a total of 162 peritonitis episodes, including 30 that were PDAP-cloudy and 132 that involved PDAP with multiple symptoms.
All patients in the cloudy group (n=30) had gram-positive bacterial infections, researchers reported, while 51.5% of the multi-symptom group had gram-positive infections (P<0.001).
Nearly all patients in the cloudy group (n=29; 96.7%) had infections that were susceptible to vancomycin, whereas slightly more than half of the patients (50.8%; n=67) in the multi-symptom group had vancomycin-susceptible illness (P<0.001).
PDAP with cloudy effluent and no other symptoms had a sensitivity of 98.48% for predicting vancomycin-susceptible infections. Only one patient in the PDAP-cloudy group had a vancomycin-resistant infection caused by Enterococcus gallinarum.
Multivariate analysis showed that cloudy effluent alone independently predicted vancomycin sensitivity, according to the study results (OR, 27.678 [95% CI, 3.19-240.10]; P=0.003).
Other independent predictors of vancomycin susceptibility were low-effluent white blood cell counts (OR, 0.988 [95% CI, 0.980-0.996]; P=0.004), diabetes (OR, 3.646 [95% CI, 1.580-8.416]; P=0.002), residual renal creatinine clearance (OR, 0.956 [95% CI, 0.918-0.995]; P=0.027), and first episode of peritonitis (OR, 0.447 [95% CI, 0.207-0.962]; P=0.039). When these factors were added to the analysis, they increased the area under the curve to 0.813 (95% CI, 0.0.749–0.878; P<0.001).
Implications of the Findings
“This study addresses PDAP, a significant complication for patients undergoing PD, and suggests clues of susceptibility to antibiotics based on the appearance of the fluid and presence of accompanying symptoms,” explains Khaled Boubes, MD, who was not involved in the study.
“This retrospective study divided PDAP cases into those with only cloudy effluent and those with additional symptoms, and it found that cloudy effluent alone was highly predictive of vancomycin-sensitive infections, suggesting potential for targeted monotherapy,” Dr. Boubes told Physician’s Weekly.
He also noted that the study was limited because it was a retrospective analysis focused on patients from a single treatment center in China.
“Whether the results can be generalized to other areas needs to be evaluated,” Boubes said. “Further research is needed to confirm these findings in a prospective study and to evaluate long-term outcomes of vancomycin monotherapy in PDAP cases presenting with only cloudy effluent fluid.”
