The genus Corynebacterium includes a high number of species that are usually isolated from human skin as saprophytes. However, these microorganisms have also been reported as infectious agents in a broad group of patients and have showed broad-spectrum resistance. We studied the susceptibility profiles against macrolides, clindamycin, and streptogramins of 254 clinical strains belonging to the species Corynebacterium urealyticum (120), Corynebacterium amycolatum (66), Corynebacterium jeikeium (17), Corynebacterium striatum (20), Corynebacterium coyleae (12), Corynebacterium aurimucosum (11), and Corynebacterium afermentans subsp. afermentans (8). The MLS(B) phenotype was detected in 186 strains and was associated with the presence of methylase enzymes codified by the erm(X) gene in 171 strains. The erm(B) gene was only detected in two C. urealyticum strains. Fourteen strains showed macrolide resistance, but they did not carry erm genes. mef genes were not detected despite eight C. amycolatum strains showed the M phenotype. Also, the presence of hydrolytic enzymes codified by ere(B) was evaluated, but all results were negative. Resistance to macrolide in Corynebacterium sp. is mainly due to the presence of erm(X) methylase, although other resistance mechanisms could be involved.
We investigated the pathogenicity, invasiveness, and genetic relatedness of 17 clinical Listeria monocytogenes stains isolated over a period of nine years (2006–2014). All isolates were phenotypically characterised and growth patterns were determined. The antimicrobial susceptibility of L. monocytogenes isolates was determined in E-tests. Invasion assays were performed with epithelial HeLa cells. Finally, L. monocytogenes isolates were subtyped by PFGE and MLST.
All isolates had similar phenotypic characteristics (β-haemolysis and lecithinase activity), and three types of growth curve were observed. Bacterial recovery rates after invasion assays ranged from 0.09% to 7.26% (1.62 ± 0.46). MLST identified 11 sequence types (STs), and 14 PFGE profiles were obtained, indicating a high degree of genetic diversity. Genetic studies unequivocally revealed the occurrence of one outbreak of listeriosis in humans that had not previously been reported. This outbreak occurred in October 2009 and affected three patients from neighbouring towns. In conclusion, the molecular epidemiological analysis clearly revealed a cluster (three human cases, all ST1) of not previously reported listeriosis cases in northwestern Spain. Our findings indicate that molecular subtyping, in combination with epidemiological case analysis, is essential and should be implemented in routine diagnosis, to improve the tracing of the sources of outbreaks.
Fourteen Corynebacterium coyleae isolates were recovered from 12 in-patients during a 5-years period. In six patients, the isolates were considered as clinically significant, three definite (sepsis), two probable (sepsis and soft tissue infection), and one possible (post-transfusional bacteremia). In the remaining 6 patients (all neonatal bacteremias), there was not enough data for considering the isolates as clinical significant. API Coryne identified all isolates as C. jeikeium, while Biolog GP2 correctly identified 7 out of the 14 isolates. Definitive identification was achieved in all isolates by the sequencing of a fragment of 724 to 1423 pb of 16S rDNA. Successive isolations from two patients presented identical random amplified polymorphic DNA (RAPD) profiles. All of the isolates were in-vitro-sensitive to beta-lactams, gentamicin, rifampin, tetracycline, vancomycin, linezolid, and resistant to clindamycin. Resistance to erythromycin occurred in 83.3% of isolates, all of them presenting phenotype cMLS and harboring the gene ermX.
The genus Janibacter comprises nine different species mainly found in the environment. Only two human infections by these microorganisms have been previously reported, one by J. melonis and another one by an undescribed Janibacter sp. Herewith we report the first human cases of infection by J. terrae in four bacteremic patients. The microorganisms were isolated from two consecutive blood cultures taken from four febrile patients with several underlying conditions. All patients were treated with antibiotics, two of them with favorable outcome. Two severely immunocompromised patients died, and one was treated with an antibiotic in vitro active against the isolate. Janibacter terrae was identified by phenotypic and 16S rDNA amplification methods. This report includes also the first data on antimicrobial susceptibility of this opportunistic pathogen. Clinical microbiologists should be aware of this microorganism which can be identified by phenotypic and molecular methods.
Background: In Europe, acute hepatitis caused by the hepatitis E virus (HEV) traditionally was an infection found in people who had travelled to endemic zones, mainly Asia and Africa. However, a growing number of sporadic autochthonous cases are now being diagnosed in the Western world.Objective: To analyze the cases of acute HEV hepatitis diagnosed in our setting, with the identification of the clinicalepidemiological characteristics.
Material and methods:We included the cases of acute HEV hepatitis diagnosed (positive anti-HEV IgM and/or HEV RNA present in serum) between January 2008 and December 2014. Different clinical, epidemiological and evolutive parameters were analyzed.Results: A total of 23 patients were identified, all originating from Spain. Fourteen cases (60.87%) presented jaundice and marked cytolysis at the time of diagnosis (aspartate aminotransferase [AST] 1,106.91 U/l and alanine aminotransferase [ALT] 1,407.04 U/l). Twenty-two cases were regarded as autochthonous, and one patient had travelled to China three months before. The mean time to resolution was 11.2 weeks. Some autoimmune markers were positive in 43.5% of the patients. Two subjects were diagnosed with previous chronic liver disease and were classified as "acuteon-chronic liver failure" (ACLF), one died and the other underwent liver transplantation.Conclusion: Acute HEV hepatitis in our setting is an autochthonous condition that is probably underdiagnosed, manifesting with jaundice and cytolysis. Autoimmune marker positivity is an epiphenomenon, which in some cases complicates the diagnosis.
Fifteen Corynebacterium ureicelerivorans isolates were recovered in pure culture from six patients during a five-year period. Five patients had bacteremia and the other was an infection of ascitic fluid. The API Coryne numerical profile obtained corresponds to the profile for C. bovis, while Biolog GP2 identified four out of the six isolates as C. jeikeium. The organisms were molecular identified by 16S rDNA and rpoB. The present report also includes information on new phenotypic tests and, for the first time, antimicrobial susceptibility data of C. ureicelerivorans and their rpoB sequences. All macrolide-resistant isolates presented a constitutive MLS phenotype. This organism must be differentiated from other slow-growing, lipophilic, and urea-splitting corynebacteria.
Corynebacterium kroppenstedtii has been associated with infections of the female breast. Genome sequencing of two strains revealed a specific genomic island in the multidrug-resistant isolate CNM633/14 with similarity to the R plasmid pJA144188 of Corynebacterium resistens DSM 45100, being indicative of the horizontal transfer of antibiotic resistance genes to C. kroppenstedtii.
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