Immunogenicity and efficacy of one dose measles-mumps-rubella (MMR) vaccine at twelve months of age as compared to monovalent measles vaccination at nine months followed by MMR revaccination at fifteen months of age.

BACKGROUND AND METHODS: measles is a common cause of morbidity and mortality in developing countries. Although the measles-mumps-rubella vaccine (MMR) is currently in use in developed countries, monovalent measles vaccine (MV) is routinely recommended by World Health Organization (WHO) at 9 months of age in Turkey, as in many other developing countries. In this study, 442 Turkish children received MV at 9 months of age and were revaccinated with MMR vaccine at 15 months of age. In the second group 495 children received MMR at 12 months of age with no earlier measles vaccination. Antibodies were measured before the first vaccination and 6 weeks after the MMR. All children had been followed for occurrence of measles infection for 60 months. Two vaccination schedules were compared for immunogenicity and protection rates. CONCLUSIONS: seroconversion and clinical protection rates were significantly higher in children who received only MMR at 12 months of age than in children revaccinated at 15 months of age. Seroconversion rate for measles was 69.9% in children who received MMR at 12 months of age and 90.3% in children revaccinated at 15 months of age (P=0.0003). While there was no measles case in children who were revaccinated, 12 (2.7%) children in the first group acquired measles during the follow-up period. Vaccination at 12 months of age appeared to be better than the current national standard. The late elimination of maternal antibodies and the inhibitory effect of a weak antibody response after the first dose of vaccine at 9 months may explain the better immunogenicity and efficacy of the MMR vaccine given at 12 months of age.

Epidemiology and antibiotic resistance of gram-negative urinary pathogens in pediatric patients.

In order to determine the etiological agents and the rate of resistance to various antibiotics, 209 consecutive gram-negative bacteria isolated from children admitted to Hacettepe University Children's Hospital with urinary tract infections were investigated over a three-month period. Of these, 46 (22%) were nosocomial isolates. The most frequently isolated organism was E.coli (n: 141) followed by Klebsiella spp. (39), Proteus spp. (19), Pseudomonas spp. (8) and Enterobacter spp. (2). In vitro susceptibilities were evaluated by microbroth dilution method, following NCCLS guidelines. Overall, 75 percent of the isolates were resistant to ampicillin, 52 percent were resistant to TMP/SMX and 25 percent to cefuroxime. Amikacin was the most active aminoglycoside; 93 percent of the isolates were susceptible to this agent, while resistance to gentamicin was 21 percent. Resistance to ceftazidime and ceftriaxone was 12 percent and 19 percent, respectively. Overall, resistance to imipenem was one percent and to ciprofloxacin three percent. These in vitro results should be taken into account before initiating empirical therapy; broad spectrum antibiotics should not be used if the isolate is susceptible to the older drugs in order to prevent the increase in resistance.