WASHINGTON — Americans’ confidence in those who provide medical treatment, teach, cover the news and provide other essential services is in decline amid a growing loss of faith in public institutions.

A Gallup survey of people’s belief in the honesty and ethics in 22 fields showed gains in just five of them going back four years, losses in 13 and no change in five.

The biggest losers in the annual survey, taken Dec. 7 to 11, were college teachers, engineers, insurance salespeople and journalists. Only psychiatrists showed significant gains.

Nurses remain by far the most trusted professionals, with 84 percent of Americans saying they have very high or high trust in them. That figure was down 1 point from last year’s record-high 85 percent. Nurses have topped the list of professions in trustworthiness every year except one since Gallup began asking about them in 1999.

People in only five other fields are held in high or very high trust by more than half of Americans: pharmacists at 67 percent, doctors at 65 percent, engineers at 65 percent, dentists at 59 percent and police at 58 percent.

Even that faith is under pressure, however. While almost two-thirds of Americans still express faith in physicians, that figure is down from a high of 70 percent four years ago.