UPDATE 1-Singapore steps up Zika prevention effort as confirmed cases rise to 56
* Ministry confirms 15 new cases on Monday
* House inspections, clean-up spreads to other parts of island
* Most of initial 41 cases have fully recovered (Recasts with latest tally)
By Nicole Nee and Imogen Braddick
SINGAPORE, Aug 29 (Reuters) - Singapore confirmed 15 new cases of locally-transmitted Zika infections on Monday, taking the tally to 56 as authorities step up efforts to contain the outbreak.
All the cases were in or near the Aljunied area in the southeast of the city-state, and most were foreign workers from a nearby construction site owned by GuocoLand, where testing for the virus is now complete, the health ministry said in a statement.
The National Environment Agency (NEA) has inspected foreign workers' dormitories as well as thousands of other premises in the area and in six other parts of the island.
Singapore, a major regional financial centre and busy transit hub, which maintains a constant vigil against the mosquito-borne dengue virus, reported its first Zika case in May, imported by a middle-aged man who had been to Brazil.
On Saturday, the health ministry confirmed a first locally-transmitted case, with the tally jumping to 41 a day later amid warnings of more likely positive cases. Continuación...