Phenotypic and Molecular Characterization of Nonfermenting Gram-Negative Bacilli Causing Peritonitis in Peritoneal Dialysis Patients.

Ana Cláudia Moro Lima Dos Santos,Aydir Cecília Marinho Monteiro,Adriano Martison Ferreira,Augusto Cezar Montelli,Thaís Alves Barbosa,Maria De Lourdes Ribeiro De Souza Da Cunha,Danilo Flávio Moraes Riboli,Carlos Henrique Camargo,Pasqual Barretti,Rodrigo Tavanelli Hernandes,Alessandro Lia Mondelli

doi:10.3390/pathogens11020218

Abstract

(1) Background: Peritonitis due to nonfermenting Gram-negative bacilli (NF-GNB) is a dramatic complication of peritoneal dialysis (PD) with bad outcomes. Previous studies of PD-related peritonitis due to Pseudomonas species have shown a low-resolution rate, without a high resistance rate to antipseudomonal antibiotics. This suggests that bacterial virulence factors can act and influence peritonitis evolution. This study aimed to describe the microbiological characteristics of NF-GNB causing PD-related peritonitis and analyze their influence on the outcome. (2) Methods: We analyze the 48 isolates from NF-GNB peritonitis, which were stored in our culture collection regarding bacterial resistance, biofilm, and other virulence factors’ production, and clonal profile. Additionally, we collected data on treatment and outcomes from patients’ clinical registers. (3) Results: The etiologies were species of Pseudomonas (50%), Acinetobacter (36%), and other NF-GNB (14%). There was a high (75%) proportion of biofilm producer lineages. The in vitro susceptibility rate of Pseudomonas spp. to amikacin, ciprofloxacin, and ceftazidime was significantly greater than that of Acinetobacter spp. and other species; however, there was a similar low-resolution rate (<45%) among the episodes attributable to them. Pseudomonas species have a polyclonal profile, while we found a clone of five multiresistant Acinetobacter baumannii over an 8-year interval (2000–2008), which suggest an origin from the healthcare environment. (4) Conclusions: We are not able to identify any predictor of outcome, but it is possible that biofilm and others virulence factors can act in concert and contribute to the bad outcome.

Highlights

Despite the substantial decrease in peritonitis rates over recent decades [1,2], it remains a major complication for chronic kidney disease patients undergoing peritoneal dialysis (PD) [2,3]
A high resistance rate was observed among nonfermenting Gram-negative bacilli (GNB) (NF-GNB) strains, except for Pseudomonas species, which were highly susceptible to the majority of antibiotics, except for ciprofloxacin. These findings suggest that bad outcomes observed in this study and in the two largest previous series [11,12], which reported PD-related peritonitis caused by Pseudomonas species, are a consequence of its aggressive virulence profile beyond antibiotic resistance
We studied all isolates of NF-GNB from PD-related peritonitis that occurred between

Summary

Introduction

Despite the substantial decrease in peritonitis rates over recent decades [1,2], it remains a major complication for chronic kidney disease patients undergoing peritoneal dialysis (PD) [2,3]. Our group reported that peritonitis is the most common cause of PD discontinuation in Latin America [4]. Davenport [3] showed similar results in London’s dialysis centers, as well as de Moraes et al, in the largest Latin American cohort of PD patients [5]. Episodes caused by Staphylococcus aureus [8] and Gram-negative bacilli (GNB), especially nonfermenting GNB (NF-GNB), present a more severe clinical course and a high non-resolution rate [9,10]

Objectives

Methods

Results

Discussion

Conclusion