Enterococcus casseliflavus septicaemia in a preterm neonate.

Enterococcus casseliflavus is a yellow-pigmented, motile, Gram-positive coccus that is only rarely isolated from clinical specimens. We report the first case of neonatal sepsis due to E. casseliflavus in a premature neonate. Precise identification of Enterococcus species is difficult but is of significant clinical interest because of the intrinsic low-level resistance to vancomycin of species such as E. casseliflavus and E. gallinarum.

Polymorphisms in the cell wall-spanning domain of the C protein beta-antigen in clinical Streptococcus agalactiae isolates are caused by genetic instability of repeating DNA sequences.

The C protein alpha- and beta-antigens are immunodominant components of the surface of Streptococcus agalactiae, the most frequent cause of neonatal sepsis. Both proteins are thought to contribute significantly to virulence of S. agalactiae. They are mainly expressed by serotypes Ia, Ib, and II. The C protein beta-antigen (Cbeta-protein) binds to the Fc portion of human IgA and seems to be of importance in bacterial resistance to mucosal immune defense mechanisms. In this study, PCR analysis of S. agalactiae isolates obtained from 189 neonates and 112 pregnant women revealed the presence of the Cbeta-protein gene in 19% and 22% of the isolates, respectively. Size polymorphisms of the PCR products within the gene region encoding the cell wall-spanning domain indicated a high degree of genetic variability. Thirteen different variants of the amplified region were differentiated among the 60 Cbeta-protein-positive isolates by sequence analysis. In all variants, the polymorphisms were caused by insertions and deletions of repetitive DNA elements that did not alter the open reading frame. Comparison of the Cbeta-protein gene polymorphisms showed a significantly higher rate of isolates carrying deletions >50 bp in serotype Ib than in serotype II isolates (p = 0.001); this was also true for neonatal isolates analyzed separately (p = 0.01). Neonatal isolates carried a higher rate of large deletions when compared with maternal isolates; this difference, however, did not reach statistical significance (p = 0.08). We hypothesize that polymorphisms in the cell wall-spanning domain of the Cbeta-protein are of functional relevance with regard to maternofetal transmission of the pathogen.

A serotype V clone is predominant among erythromycin-resistant Streptococcus agalactiae isolates in a southwestern region of Germany.

One hundred ninety-three Streptococcus agalactiae isolates of neonatal origin and 146 isolates from adult women were analyzed for macrolide resistance and investigated for clonality. Among erythromycin-resistant isolates, serotype V turned out to be the most frequent. Comparative pulsed-field gel electrophoresis analysis revealed genetic clustering of resistant strains and predominance of a single clone family within an otherwise heterogeneous serotype V population.