Standard mouth cleaning protocol (without brushing) included:

1. Preparation of sterile catheter (12F lub 14F), suction of excess fluid from the oral cavity.

2. Using Sage Suction Swab (Toothette®), soaking in Perox-A-Mint Solution and cleaning with circular movements of each mucosal site for 10 seconds:

   1. Right cheek mucosa and right upper quadrant
   2. Left cheek mucosa and left upper quadrant
   3. Left lower buccal quadrant
   4. Right lower buccal quadrant

3. Moisturizing with Mouth Moisturizer /firma/ of oral cavity mucosa, tongue and lips.

4. Repeated suction of excess fluid from the oral cavity.

Extended mouth cleaning protocol (with brushing) included:

1. Preparation of sterile catheter (12F lub 14F), suction of excess fluid from the oral cavity.

2. Teeth brushing (each teeth quadrant for 30) using Sage Untreated Suction Toothbrush (SUST) connected to suction unit, moistured with sterile water.

3. Using Sage Untreated Suction Toothbrush (SUST) moisturised with sterile water and cleaning with circular movements of each mucosal site for 10 seconds:

   1. Right cheek mucosa and right upper quadrant
   2. Left cheek mucosa and left upper quadrant
   3. Left lower buccal quadrant
   4. Right lower buccal quadrant

4. Moisturizing with Mouth Moisturizer of oral cavity mucosa, tongue and lips.

5. Repeated suction of excess fluid from the oral cavity.

Interventions included 2 variants of oral hygienic procedures. One was extended of teeth brushing.

Healthcare-associated infection (HAI) incidence was measured.

Using The Beck Oral Assessment Scale (BOAS)

Frequency of identification of Enterococcus fecalis, Acinetobacter baumannii, Klebsiella pneumoniae in different samples from oral cavity taken from ventilated COVID-19 patients on Intensive Care Unit.