Using MALDI-TOF MS typing method to decipher outbreak: the case of Staphylococcus saprophyticus causing urinary tract infections (UTIs) in Marseille, France

Staphylococcus saprophyticus is one of the leading causes of urinary tract infections (UTI). In December 2014, our surveillance system identified an abnormal increase in S. saprophyticus causing UTIs in four university hospitals in Marseille, indicating a suspected community S. saprophyticus UTI outbreak. This was detected by our surveillance system BALYSES (Bacterial real-time Laboratory-based Surveillance System). S. saprophyticus/ Escherichia coli UTI ratio increased three-fold from 0.0084 in 2002 to 0.025 in December 2015 in Marseille with an abnormal peak in December 2014, and with an annual estimated ratio trend of 5.10 −6 ( p -value