Gordonia Species as Emerging Causes of Continuous-Ambulatory-Peritoneal-Dialysis-Related Peritonitis Identified by 16S rRNA and secA1 Gene Sequencing and Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)

Abstract

We report here four cases of continuous ambulatory peritoneal dialysis-related peritonitis caused by three different species of Gordonia. The portal of entry was likely through Tenckhoff catheters. 16S rRNA and secA1 gene sequencing are so far the most reliable methods for the accurate identification of Gordonia species. Gordonia species are Gram-positive weakly acid-fast coryneform bacteria. Although Gordonia species have been implicated in a variety of infections, only seven cases of continuous ambulatory peritoneal dialysis (CAPD)-related peritonitis caused by Gordonia species have been described (1-4). Furthermore, the methods used for identifying these seven Gordonia isolates were not mentioned in five cases (2, 4), and the accuracy of the identifications could not be ascertained. In this article, we described four cases of CAPD-related peritonitis caused by three different species of Gordonia confirmed by 16S rRNA and secA1 gene sequencing.Clinical specimens were collected and handled according to standard protocols, and the clinical data were collected by analyzing the patients' hospital records. Phenotypic identification was performed using standard conventional biochemical methods and the API Coryne system (bioMérieux, France). All tests were performed in triplicate. The MICs were determined using Etests (bioMérieux), according to the standards of the Clinical and Laboratory Standards Institute (CLSI) (5), with Escherichia coli strain ATCC 25922 and Pseudomonas aeruginosa strain ATCC 27853 as controls; the results were compared with the CLSI MIC interpretive standards for Staphylococcus spp. and Streptococcus pneumoniae (6) for evaluation. Bacterial DNA extraction, PCR amplification, and DNA sequencing of the 16S rRNA and secA1 genes were performed according to our previous publication (7), except for the primer pairs used (G268F/G1096R [8] for the 16S rRNA gene and SecA1-f/SecA1-r [9] for the secA1 gene). Comparative sequence identity analysis and phylogenetic analysis using the maximum likelihood method were performed according to our previous publication (10), except that MEGA 6.06 (11) was used instead. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was performed according to our previous publication (12), and the protein profiles obtained were processed and analyzed using MALDI Biotyper 3.1 (Bruker Daltonics, Germany) for the generation of the hierarchical cluster analysis (HCA) dendrogram and for identification. Case 1. A 65-year-old Chinese man was admitted for cloudy dialysis effluent for 1 day. He had end-stage renal failure (ESRF) of unknown etiology and had been undergoing CAPD for 7 years. He was afebrile but had turbid dialysis effluent. The total leukocyte count of the dialysis fluid was 930/mm 3 , with neutrophil predominance. A Gram smear of the dialysis effluent after centrifugation revealed numerous leukocytes without any organisms. Empirical intraperitoneal (i.p.) cefazolin and gentamicin therapies were started. As the clinical condition of...

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) score algorithm for identification of Gordonia species

“…Of the 39 Gordonia species described to date only 10 have been identified as opportunistic pathogens in humans capable to cause a wide range of diseases ranging from primary cutaneous infections or lung infections to bacteremia or recurrent breast abscesses in healthy individuals as well as in immunocompromised patients (Sowani et al 2017 ; Rodríguez-Lozano et al 2016 ). Gordonia is difficult to identify using conventional biochemical tests as reflected in some reports (Tindall and Euzéby 2001 ; Lam et al 2014 ) where all Gordonia isolates were misidentified as Rhodococcus species. To date, sequencing of the 16S rRNA gene has become the most reliable technique for Gordonia species identification (Bizzini et al 2010 ).…”

“…Recently, MALDI-TOF MS based system has emerged as new tool with the possibility to identify most of the microorganisms causing human infections (Lam et al 2014 ). Different studies evaluated the precision of MALDI-TOF MS for Gordonia species identification with not very promising results (Hsueh et al 2014 ; Rodríguez-Lozano et al 2016 ; Barberis et al 2014 ; Bizzini et al 2010 ; Lai et al 2010 ).…”

“…Measurements were carried out in triplicate and the average of the three results was used for analysis (Bizzini et al 2010 ). Since Gordonia have been previously classified using biochemical tests as Rhodococcus (Tindall and Euzéby 2001 ; Lam et al 2014 ), six Rhodococcus equi clinical isolates were also tested by MALDI-TOF to assess the possibility of misidentification with Gordonia species.…”

First identification of Gordonia sputi in a post-traumatic endophthalmitis patient – a case report and literatures review

“…as other gram-positive bacilli, such as Rhodococcus or Nocardia spp. However, so far bacterial rRNA gene sequencing analysis has proven to be a more accurate measurement [10]. As Lai CC et al reported, in a group of 66 isolates previously identified as Rhodococcus spp.…”

Bacteremia due to Gordonia polyisoprenivorans: case report and review of literature

“…They are sometimes dismissed as Corynebacteria , Nocardia , or Rhodococcus species [12, 13, 16, 17]. It is also believed that the incidence of Gordonia infections has been underestimated.…”