Is a Meningococcal Booster Needed?
Immunity waned significantly within 2–3 years after toddlers were vaccinated with MCV4, a study of sera from 48 vaccinated and 47 unvaccinated children found (Pediatr. Infect. Dis. J. 2005;24:132–6). The vaccine was given at ages 2–3 years, and sera were tested at ages 4–5 years. Although the vaccinated children had higher antibody concentrations and more frequent passive protective activity, compared with unvaccinated children, serum antibody concentrations were sufficient in only 15% of vaccinated children.
“A booster dose may be needed in this age group for prevention of meningococcal infection,” Dr. Azimi said.
Battling Biofilms
A “tantalizing” study showed that subinhibitory concentrations of aminoglycoside antibiotics induce formation of biofilms and antibiotic resistance in Pseudomonas aeruginosa, Escherichia coli, and possibly other gram-negative organisms—“potentially contributing to some chronic or recurrent infections,” Dr. St. Geme said (Nature 2005;436:1171–5).
Biofilms are aggregates of bacterial cells that form on biotic and abiotic surfaces, including human tissue. They have been implicated in cystic fibrosis, endocarditis, urinary tract infections, osteomyelitis, and otitis media, among other infections. The study identified a P. aeruginosa gene that was essential for biofilm induction and aminoglycoside resistance related to biofilms.
“In thinking about how to apply this information, one possibility is that inhibition of this novel gene product may be beneficial in early treatment of P. aeruginosa airway infection, in particular when tobramycin aerosol is being used,” Dr. St. Geme said.
More rapid, more sensitive techniques to screen for GBS colonization are required. Dr. St. Geme
A booster dose may be needed for 4− to 5-year-olds to prevent meningococcal infection. DR. AZIMI