Epidemiological and clinical characteristics of Streptococcus tigurinus endocarditis.

BACKGROUND: Streptococcus tigurinus was recently described as a new streptococcal species within the viridans group streptococci (VGS). The objectives of the present work were to analyse the clinical and microbiological characteristics of S. tigurinus isolated from patients with bacteraemias, to determine the prevalence of S. tigurinus among VGS endocarditis in Spain, and to compare the clinical characteristics and outcomes of endocarditis caused by S. tigurinus and other VGS. METHODS: Retrospective nationwide study, performed between 2008 and 2016 in 9 Spanish hospitals from 7 different provinces comprising 237 cases of infective endocarditis. Streptococcal isolates were identified by sequencing fragments of their 16S rRNA, sodA and groEL genes. Clinical data of patients with streptococcal endocarditis were prospectively collected according to a pre-established protocol. RESULTS: Patients with endocarditis represented 7/9 (77.8%) and 26/86 (30.2%) of the bacteraemias caused by S. tigurinus and other VGS, respectively (p < 0.001), in two of the hospital participants. Among patients with streptococcal endocarditis, 12 different Streptococcus species were recognized being S. oralis, S. tigurinus and S. mitis the three more common. No relevant statistical differences were observed in the clinical characteristics and outcomes of endocarditis caused by the different VGS species. CONCLUSIONS: In this multicenter study performed in Spain, S. tigurinus showed a higher predilection for the endocardial endothelium as compared to other VGS. However, clinical characteristics and outcomes of endocarditis caused by S. tigurinus did not significantly differ from endocarditis caused by other oral streptococci.

Characterization of plasmids carrying the blaOXA-24/40 carbapenemase gene and the genes encoding the AbkA/AbkB proteins of a toxin/antitoxin system.

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAb) is a major source of nosocomial infections in Spain associated with the production of OXA-58-like or OXA-24/40-like ß-lactamase enzymes. We analysed the plasmids carrying the bla(OXA-24/40)-like gene in CRAb isolates obtained a decade apart. METHODS: The presence of ß-lactamases was screened for by PCR (metallo-ß-lactamases, carbapenem-hydrolysing class D ß-lactamases, GES and KPC) in 101 CRAb isolates obtained in two multicentre studies (GEIH/REIPI-Ab-2000 and GEIH/REIPI-Ab-2010; n = 493 Acinetobacter spp). We analysed the distribution and characterization of the plasmids carrying the bla(OXA-24/40)-like gene and sequenced two plasmids, AbATCC223p (2000) and AbATCC329p (2010) from A. baumannii ATCC 17978 transformants. RESULTS: Acquisition of the bla(OXA-24/40)-like gene was the main mechanism underlying resistance to carbapenems (48.7% in 2000 compared with 51.6% in 2010). This gene was mainly isolated in ST2 A. baumannii strains in both studies, although some novel STs (ST79 and ST80) appeared in 2010. The gene was located in plasmids (8-12 kbp) associated with the repAci2 or repAci2/repGR12 types. The sequences of AbATCC223p (8840 bp) and AbATCC329p (8842 bp) plasmids were similar, particularly regarding the presence of the genes encoding the AbkA/AbkB proteins associated with the toxin/antitoxin system. Moreover, the abkA/abkB gene sequences (>96% identity) were also located in plasmids harbouring the bla(OXA-58)-like gene. CONCLUSIONS: The action of OXA-24/40 and OXA-58 ß-lactamase-like enzymes represents the main mechanism underlying resistance to carbapenems in Spain in the last decade. AbkA/AbkB proteins in the toxin/antitoxin system may be involved in the successful dissemination of plasmids carrying the bla(OXA-24/40)-like gene, and probably also the bla(OXA-58)-like gene, thus contributing to the plasmid stability.

Recurrent respiratory infection caused by Bordetella bronchiseptica in an immunocompetent infant.

Bordetella bronchiseptica rarely infects immunocompetent humans. We report an unusual case of recurrent pertussis-like syndrome caused by B. bronchiseptica in a 7-month-old immunocompetent boy. Molecular analysis demonstrated that the isolates from the child and mother were identical.