Corynebacterium striatum is a potentially pathogenic microorganism
that causes nosocomial outbreaks. However, little is known about its virulence
factors that may contribute to healthcare-associated infections (HAIs). We
investigated the biofilm production on abiotic surfaces of multidrug-resistant (MDR)
and multidrug-susceptible (MDS) strains of C. striatum of
pulsed-field gel electrophoresis types I-MDR, II-MDR, III-MDS and IV-MDS isolated
during a nosocomial outbreak in Rio de Janeiro, Brazil. The results showed that
C. striatum was able to adhere to hydrophilic and hydrophobic
abiotic surfaces. The C. striatum 1987/I-MDR strain, predominantly
isolated from patients undergoing endotracheal intubation procedures, showed the
greatest ability to adhere to all surfaces. C. striatum bound
fibrinogen to its surface, which contributed to biofilm formation. Scanning electron
microscopy showed the production of mature biofilms on polyurethane catheters by all
pulsotypes. In conclusion, biofilm production may contribute to the establishment of
HAIs caused by C. striatum.
Background
Corynebacterium striatum
is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR
C. striatum
isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro.
Methods
C. striatum
isolates were identified by 16S rRNA and
rpoB
genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy.
Results
Eleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the
gyrA
gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the
gyrA
gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter.
Conclusions
Genotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR
C. striatum
is a case of concern.
Electronic supplementary material
The online version of this article (10.1186/s12879-019-4294-7) contains supplementary material, which is available to authorized users.
The increasing problems with multidrug resistance in relation to mupirocin, aztreonam, ceftazidime, and/or oxacillin, ampicillin, penicillin, tetracycline, clindamycin, lincomycin, and erythromycin. This study presents the antimicrobial susceptibility profiles of Brazilian C. diphtheriae isolates. The data are of value to practitioners, and suggest that some concern exists regarding the use of penicillin.
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