Identification and diversity of multiresistant Corynebacterium striatum clinical isolates by MALDI-TOF mass spectrometry and by a multigene sequencing approach

Abstract

BackgroundThe genus Corynebacterium is composed of Gram-positive bacteria that are widely distributed throughout the environment; these bacteria are also part of the normal microbiota of human skin and mucous membranes. Multiple studies have shown that species of this genus, including C. striatum, become pathogenic to humans under special conditions. Our aim was to determine the characteristics of clinical multiresistant strains of C. striatum that were isolated in our geographical region, to determine their diversity, and to compare them with the type strain and with related species. We studied fifty-two strains of C. striatum isolated from different hospitals from Mallorca, Spain, mainly from the Hospital Joan March in Bunyola, Mallorca. Most of the strains were isolated from sputum cultures of respiratory samples from patients with chronic obstructive pulmonary disease. To gain further insight into the genetic diversity of the strains, we analysed several housekeeping genes and other genes associated with antibiotic resistance. Strains were also characterised phenotypically by their antibiotic resistance profiles and by MALDI-TOF mass spectrometry analysis.ResultsThe ITS1 region, gyrA and rpoB were chosen as the appropriate genes in the C. striatum genome to study the genetic diversity of C. striatum species and to discriminate between strains. After analysing these three genes, four sequence types (ST2, ST4, ST1 and ST11) were found to be the most abundant. Splits tree analysis of the strains demonstrated that these clinical isolates did not share any alleles with the type strain of the species. Recombination was detected within all of the C. striatum isolates, and different clonal populations were detected within the samples.ConclusionsOur results demonstrate that the isolates were best identified using gene-based molecular methods; using these methods, the isolated strains were determined to be different from the type strain of C. striatum. The ITS1 region and the gyrA and rpoB genes were selected because of their variability and were the most useful tools for discriminating between strains. The phenotype and antibiotype characteristics of the strains did not seem suitable for typing purposes. MALDI-TOF mass spectrometry can be a useful method for identifying and discriminating between C. striatum strains.

Rapid transmission of multidrug-resistant Corynebacterium striatum among susceptible patients in a tertiary hospital in China

“…The cultures were collected, C. striatum DNA was extracted using a bacterial DNA extraction kit (Qiagen, Hilden, Germany), and amplification of 16S-rRNA gene was performed as previously described [13]. The amplification products were sequenced and the obtained sequences were compared with that of C. striatum ATCC6940.…”

Characteristics of Multidrug-Resistant <i>Corynebacterium</i> spp. Isolated from Blood Cultures of Hospitalized Patients in Japan

“…Furthermore, Corynebacterium striatum was reported as an emerging pathogen in both immunocompetent and immunocompromised hosts (17). For these reasons, it was deemed a priority to establish more reliable methods to identify Corynebacterium clinical isolates at the species level (2,10,18,19). There is still little information regarding bloodstream infections caused by Corynebacterium spp., or the characteristics of devices related to infections caused by Corynebacterium spp.…”

Identification of Clinical Corynebacterium striatum Strains by PCR-Restriction Analysis Using the RNA Polymerase β-subunit gene (rpob)

“…In Api Coryne database C. amycolatum, C. minutissimum, and C. striatum gave the same code: (2-3)100(1-3) (0-2)(4-5). Their differential identification by biochemical tests remains difficult, and several misidentifications have been previously reported [9][10][11]. Although they are genetically different, these species share many phenotypic characteristics and we need supplementary tests to differentiate them [12].…”