An outbreak of XXXX on the neonatal unit: a tale of two clones.

@entity1 @entity5134 @entity2118 @entity580 @entity922
Serratia spp. are an important cause of @entity580 and outbreaks in high-risk settings. Twenty-one @entity1 were infected or colonized over a nine-month period during 2001-2002 on a neonatal unit. Twenty-two isolates collected were examined for antibiotic susceptibility, beta-lactamase production and genotype. Random-amplified polymorphic DNA polymerase chain reaction and pulsed-field gel electrophoresis revealed that two clones were present. The first clone caused invasive @entity922 in four babies, and was subsequently replaced by a non-invasive clone that affected 14 babies. Phenotypically, the two strains also differed in their prodigiosin production; the first strain was non-pigmented whereas the second strain displayed @entity2118 . Clinical features suggested a difference in their pathogenicity. No environmental source was found. The outbreak terminated following enhanced compliance with infection control measures and a change of antibiotic policy. Although @entity5134 continued to be isolated occasionally for another five months of follow-up, these were sporadic isolates with distinct molecular typing patterns.
