American teenager Missy Franklin became the first woman to win six golds at a single world championship when she helped the United States to victory in the 4x100 metres medley relay yesterday.

The 18-year-old swam the opening, backstroke leg in the hilltop pool in Barcelona and the US triumph followed her titles this week in 100m and 200m backstroke, 200m freestyle and the 4x100m and 4x200m freestyle relays. She was fourth in Friday’s 100m freestyle.

Franklin’s sixth gold is one more than the previous record of five she jointly held with compatriot Tracy Caulkins and Australia’s Libby Trickett.

The only other woman to win six golds at a world championships or Olympics is East German Kristin Otto at the 1988 Summer Games in Seoul.

France were handed a shock victory in the men’s 4x100 metres medley relay when gold-medal favourites United States were disqualified.

The Americans touched first in three minutes 30.06 seconds before the stadium announcer said they had been disqualified “for an early exchange”. Although Nathan Adrian of the USA touched the wall first, judges ruled Kevin Cordes had dived in too early on the second leg, causing the disqualififcation. 

France clocked a time of 3:31.51 to take gold, with Australia winning silver in 3:31.64 and Japan bronze in 3:32.26.

The Americans were denied what would have been a 12th triumph in the event in 15 championships since the inaugural edition in Belgrade in 1973.

Hungary’s Katinka Hosszu won the women’s 400m individual medley gold as Olympic champion and world-record holder Ye Shiwen of China finished a disappointing seventh.

Having already won 200m IM gold and 200m butterfly bronze, Hosszu, who had been on course to break Ye’s world record, clocked 4min 30.41sec with Spain’s Mireia Belmonte, who received noisy support at the Palau Sant Jordi stadium, at 0.80 back and Elizabeth Beisel, of the United States, at 1.28 adrift.

Having finished fourth in the 200m IM final last Monday, the 17-year-old Ye had another disappointing swim as she finished 8.10sec behind Hosszu.

Ye took the Olympics by storm when she won both the 200 and 400m IM titles, swimming the final leg of the latter in a faster time than men’s winner Ryan Lochte to set the world record of 4min 28.43sec.

Ye’s time in the Barcelona 400m IM final was just over 10 seconds slower than her world record in London.