Enhancement of bactericidal activity against group B streptococci with reduced penicillin susceptibility by uptake of gentamicin into cells resulting from combination with ß-lactam antibiotics.

Combined effects of penicillin (PEN) and gentamicin (GM) against Streptococcus agalactiae, i.e. group B streptococci (GBS), are known to occur, but synergy has not been examined in strains with reduced PEN susceptibility, usually called PEN-resistant GBS (PRGBS). We therefore studied combined effects of ß-lactam antibiotics and GM in cultures of 3 PRGBS strains belonging to serotype Ia or III that were isolated from Japanese adults with invasive infections. Killing kinetics were determined at 2-h intervals from 0 to 6 h after exposure to ampicillin (AMP) or cefotaxime (CTX) combined with GM. Concentrations of GM in bacterial cells were measured by liquid chromatography-tandem mass spectrometry. Morphologic changes after exposure to agents were observed by transmission electron microscopy. Combining AMP or CTX with GM synergistically increased bactericidal activity against PRGBS beyond that of either ß-lactam alone. GM concentrations in bacterial cells increased 5- to 8-fold when GM was combined with AMP or CTX. Electron microscopically, bacterial cells showed aggregates of strands and ribosomal damage most likely reflecting enhanced GM uptake into bacterial cells. This uptake appeared to result from cell wall damage caused by ß-lactam antibiotics. This study suggests that combining ß-lactam antibiotics with GM might be useful against severe PRGBS infection.

Eosinophilic gastrointestinal disorders in infants: a Japanese case series.

BACKGROUND: Eosinophilic gastrointestinal disorders (EGIDs) are disorders characterized by primary eosinophil inflammation in the gastrointestinal tract. There are a small number of reports of eosinophil infiltration in gastrointestinal tracts presenting as EGIDs in infants. In this study, we present Japanese cases of EGIDs in infants. METHODS: Five patients diagnosed with or strongly suspected to have EGIDs in our hospital from 2008 to 2010 were reviewed. Radiographic contrast enema examinations and/or endoscopies were performed in 4 and 3 patients, respectively. RESULTS: There were patients with eosinophilic colitis (1 suspected and 2 biopsy-proven), a patient who was suspected of having allergic eosinophilic enterocolitis, and a patient with eosinophilic gastroenteritis associated with pediatric hypereosinophilic syndrome. CONCLUSIONS: The causes and clinical findings of patients with intestinal eosinophil inflammation vary. Therefore, deliberate examination and observation are important for patients with infantile EGID.