Previous antibiotic consumption and other risk factors for carriage of penicillin-resistant Streptococcus pneumoniae in children

As part of the South Swedish Pneumococcal Intervention Project, aimed at re ducing the spread of penicillin-resistant pneumococci with MICs for penicil lin G greater than or equal to 0.5 mg/l (PRP), all patients in Malmohus cou nty, southern Sweden, with a culture positive for PRP were followed up by m eans of repeated nasopharyngeal cultures until PRP-negative. If a child car rying PRP attended a day-care centre, nasopharyngeal cultures were obtained from the other children and staff. All children screened for PRP carriage in 30 day-care centres with an identified index case were included in the a nalysis, and several outcome variables (antibiotic consumption during the p receding 6 months, previous health and social situation) were assessed in r elation to the end-point PRP carriage. Of 1036 children, 128 were found to be PRP carriers and 908 were PRP non-carriers. The PRP carriers had higher antibiotic consumption, were younger and were more often of male sex than t he non-carriers (P< 0.05). Consumption of antibiotics during the preceding 6 months was noted in 53% of carriers and 45% of non-carriers (relative ris k 1.20, 95% confidence interval 1.01-1.43), When adjusting for age, gender and day-care centre attendance, recent consumption of cotrimoxazole (trimet hoprim/sulfamethoxazole) emerged as an independent risk factor for PRP-carr iage (relative risk 3.48, 95% confidence interval 1.10-11.07). The PRP-carr iage rate in three day-care centres with high cotrimoxazole consumption was significantly higher (24%) than in the other day-care centres (10%) (P<0.0 05). The results indicate that measures aimed at reducing consumption of an tibiotics in general, and cotrimoxazole in particular, may decrease the inc idence of penicillin resistance, but such measures are, by themselves, prob ably not sufficient to halt the spread.