Comparison of arbitrarily primed polymerase chain reaction, ribotyping, and monoclonal antibody analysis for subtyping Legionella pneumophila serogroup 1.

Arbitrarily primed polymerase chain reaction (AP-PCR) was usedtocharacterize LegioneUa pneumophila serogroup1.Cells fromasingle colony could besubtyped byAP-PCRwithin afewhours. Thediscrimination between strains ofL.pneumophila serogroup1 byAP-PCRwas equivalent tothatbymonoclonal antibody analysis andribotyping. Fourstrains representing themonoclonal antibody pattern mostfrequently associated withoutbreaks allyielded unique amplicon patterns byAP-PCR. Legionella pneumophila serogroup1isthemajor etiologic agentoflegionellosis andalso theserogroupmostfrequently isolated fromtheenvironment (7). A numberofmolecular techniques havebeenusedforsubtyping serogroup1,including monoclonal antibody (MAb)typing (4),plasmid profile analysis (6), multilocus enzyme electrophoresis (14), analysis ofrestriction fragment length polymorphisms (RFLP)withor without theuse ofprobes(9,15),and pulsed-field gelelectrophoresis (10). Thesemethods have beencompared inseveral summary or review articles (14, 15). Mosthaveproved useful undercertain circumstances, butmany areunsuitable forgeneral laboratory use.The Centers forDisease Control andPrevention procedure to discriminate subtypes ofL.pneumophila serogroup1usesa panel ofseven MAbs.TheseMAbswere suggested as an international standard (4); however, these reagents arenot readily available, andmany laboratories depend on alternate procedures tosubtype these bacteria. Currently, 10subtypes ofL.pneumophila serogroup1havebeenidentified withthis panel ofMAbs.These10typestrains were characterized by twoadditional methods, rRNAprobing ofRFLP(ribotyping) andarbitrarily primed polymerase chain reaction (AP-PCR). AP-PCRisbased on theamplification ofgenomic DNA withasingle primer ofarbitrary nucleotide sequencegenerating polymorphisms that aredetected electrophoretically in agarosegels(16). Thisassayhasbeenusedtocharacterize Staphylococcus spp.(13), Candida spp.(5), andHelicobacterpylori (1). We applied this technique tothedifferentiation ofL.pneumophila serogroup1.