Community distribution of azithromycin has an important role to play in trachoma control. Previous studies have suggested that this may increase the prevalence of macrolide-resistant Streptococcus pneumoniae. S. pneumoniae was isolated from children under 7 years of age in Rombo District, northern Tanzania, before and 2 and 6 months after community-wide administration of azithromycin. Overall carriage rates were 11, 12, and 7%, respectively. Only one macrolide-resistant isolate carrying the mef gene was obtained 6 months after azithromycin administration. This contrasted with cotrimoxazole and penicillin resistance, both of which were common (cotrimoxazole resistance, 42, 43, and 47%, and penicillin resistance, 21, 17, and 16% at baseline, 2 months, and 6 months, respectively). There was a significant association between cotrimoxazole and penicillin resistance (P < 0.0001, Fisher's exact). These data suggest that in communities where macrolide resistance is rare, azithromycin distribution for trachoma control is unlikely to increase the prevalence of resistant organisms.

This is a substudy of a larger randomized controlled trial on HIV-infected Zambian children, which revealed that cotrimoxazole prophylaxis reduced morbidity and mortality despite a background of high cotrimoxazole resistance. The impact of cotrimoxazole on the carriage and antibiotic resistance of Streptococcus pneumoniae and Haemophilus influenzae as major causes of childhood mortality in HIV-infected children was investigated since these are unclear. Representative nasopharyngeal swabs were taken prior to randomization for 181 of 534 children (92 on cotrimoxazole and 89 on placebo). Bacterial identification and antibiotic susceptibility were performed by routine methods. Due to reduced mortality, prophylactic cotrimoxazole increased the median time from randomization to the last specimen from 48 to 56 months (P ‫؍‬ 0.001). The carriage of H. influenzae was unaltered by cotrimoxazole. Carriage of S. pneumoniae increased slightly in both arms but was not statistically significant in the placebo arm. In S. pneumoniae switching between carriage and no carriage in consecutive pairs of samples was unaffected by cotrimoxazole (P ‫؍‬ 0.18) with a suggestion that the probability of remaining carriage free was lower (P ‫؍‬ 0.10). In H. influenzae cotrimoxazole decreased switching from carriage to no carriage (P ‫؍‬ 0.02). Cotrimoxazole resistance levels were higher in postbaseline samples in the cotrimoxazole arm than in the placebo arm (S. pneumoniae, P < 0.0001; H. influenzae, P ‫؍‬ 0.005). Cotrimoxazole decreased switching from cotrimoxazole resistance to cotrimoxazole sensitivity in S. pneumoniae (P ‫؍‬ 0.002) and reduced the chance of H. influenzae remaining cotrimoxazole sensitive (P ‫؍‬ 0.05). No associations were observed between the percentage of CD4 (CD4%), the change in CD4% from baseline, child age at date of specimen, child gender, or sampling month with carriage of either pathogen.

Serotyping Streptococcus pneumoniae is a technique generally confined to reference laboratories, as purchasing pneumococcal antisera is a huge investment. Many attempts have been made to modify serological agglutination techniques to make them more accessible, and more recently developments in serotyping have focused on molecular techniques. This paper describes a PCR assay which amplifies the entire capsulation locus between dexB and aliA. Amplicons are digested to produce serotype-specific patterns. We have shown, using 81 epidemiologically unrelated strains representing 46 different serotypes, that the patterns correlate with a 90 to 100% similarity range for the same serotype or serogroup. Prospective testing of 73 isolates of unknown serotype confirmed reliable serotype attribution, and serotype profiles are reproducible on repeated testing. Once our database contains all 90 serotypes, this technique should be fully portable, cost-effective, and useful in any laboratory with sufficient molecular experience.The species Streptococcus pneumoniae possesses more than 90 serotypes defined by their polysaccharide capsule (1). Immunologically similar serotypes, such as 19F, 19A, 19B, and 19C, are grouped together in serogroups. The immune response to capsular polysaccharide is critical for recovery from infection (17), and the first effective treatment for pneumococcal infection, serum therapy, depended on identifying the infecting serotype rapidly so that type-specific horse serum could be administered (9). The capsule is the focus for the development of an effective vaccine, initially with the 23-valent polysaccharide and more recently the protein-polysaccharide conjugate preparations that are undergoing clinical evaluation and have entered clinical use (1, 35). Some reports on the implementation of the conjugate vaccine in different communities show that there is an increase in the carriage of serotypes that are not included in the vaccine (6, 7). Additionally, serotype surveillance in developing countries and special populations, such as Aboriginal Australians, suggests that vaccine serotype coverage may be lower than for the United States and Europe, from which surveillance data were considered in vaccine formulations (2, 4, 25). Thus, there is a continuing need to study the epidemiology of S. pneumoniae as defined by capsular polysaccharide in monitoring the effect of conjugate vaccines and to aide in the development of new vaccine formulations for developing countries and special populations (12,13,16).Effective serotyping depends on a full set of group-and type-specific antisera prepared by the Statens Serum Institut (14), an investment that is beyond the resources of many laboratories. Therefore, most laboratories confine typing to the serotypes and serogroups found in the 23-valent vaccine, which represent most of the invasive types found in industrialized countries (22). As prevailing serotypes change, a wider selection of sera will be required to cover common types, thus increasing the cost. In additio...