title: Incidence of R factors in children. 2. Contribution to the ecology of R factors in child communities.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D002648:Child; D003604:Czechoslovakia; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification*; D005111:Extrachromosomal Inheritance; D006801:Humans; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D012007:Rectum / Q000382:microbiology; D012572:School Health Services; D012578:Schools, Nursery; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000667:Ampicillin; D013752:Tetracycline