Rapid investigation of cases and clusters of Legionnaires' disease in England and Wales using direct molecular typing

Evaluation ofLegionellareal-time PCR against traditional culture for routine and public health testing of water samples

“…For three investigations, qPCR‐positive samples rapidly indicated the source of infection, later confirmed by culture and subsequent SBT of culture isolates (Mentasti et al . ). For one case, investigation linked to a heated birthing pool (Collins et al .…”

“…) and one outbreak involving a spa pool, rapid direct‐nested sequenced‐based typing was performed on LP1 qPCR‐positive DNA extracts (Mentasti et al . ) allowing epidemiological linking of patients and sources within 48 h. For a cluster of eight cases, qPCR rapidly indicated a spa pool as a potential source, but this could not be confirmed by culture due to contamination of the sample with other microbiota. Remedial action was taken on the qPCR alone.…”

“…For two outbreaks, DNA extracts from the environmental qPCR underwent direct SBT to epidemiologically link three patients to the sources (Mentasti et al . ). This was achieved in approximately 48 h. For the three outbreaks and the eight other investigations, qPCR provided a negative screening tool to rapidly rule out potential sources and support local authority investigators in prioritizing resources.…”

Genomic investigation of a suspected outbreak of Legionella pneumophila ST82 reveals undetected heterogeneity by the present gold-standard methods, Denmark, July to November 2014

“…An attempt to culture the causative agent in all cases of LD is important, but even without isolation, the examination of positive respiratory samples is of great value to include or exclude cases from an outbreak as shown recently by Mentasti and co-workers [10] and in this study. Despite the fact that isolate submission is only voluntary in Denmark, the continued submission of isolates is of pronounced value for national surveillance, as well as submission of positive PCR samples where isolation is not possible.…”

“…Available PCR-positive culture-negative samples were investigated by a real-time PCR targeting the serogroup 1 marker wzm [9,10] to discriminate between L. pneumophila serogroup 1 and non-serogroup 1. A positive result in the wzm PCR was considered as serogroup 1 whereas PCR-positive sample with a cycle threshold (CT) value of ≤ 35 in the specific L. pneumophila real-time PCR ( mip specific PCR, in-house, SSI ) but with no amplification with the wzm primers was considered as non-serogroup 1.…”