The cleanliness of some ambulances was unacceptable
Dirty ambulances and equipment have put patients at risk of infections, according to a report by the Care Quality Commission.
Inspectors carried out spot-checks at seven East Midlands Ambulance Service (EMAS) stations and discovered a catalogue of hygiene problems.
Medical equipment that should have been binned after one use was cleaned and re-used, the report found.
EMAS said it had put measures in place to address the concerns raised.
Some emergency ambulances that were checked had not been thoroughly cleaned.
The report said the interior of the vehicles "was not of an acceptable standard and many surfaces , both horizontal and vertical, were visibly dirty".
Not all of the ambulances inspected in Leicestershire had a supply of hand detergent wipes, which are key to helping stop the spread of superbugs such as MRSA and clostridium difficile (C Diff).
Stretchers, ventilator units and defibrillators were also found to be dirty.
Officials from the commission found 19 of the 30 staff they spoke to had not received formal training on prevention and control of infections for more than two years because they were too busy.
The Care Quality Commission has now given EMAS one month to improve.
Ambulance bosses said the trust had now put an action plan in place.
Chris Gaskill, from EMAS, said: "Patient care is obviously our priority.
He said an action plan had been together to address seven areas of concern.
"It has been monitored closely by our executive directors and that plan is already starting to go into place.
"We need to make improvements and we recognise that."