Background Proteus mirabilis is an opportunistic microorganism, which is an indicator of dirtiness on clinics and wards of the hospital.

Purpose To determine the number of isolates and sensitivity of P. mirabilis to antibiotics.

Materials and Methods Retrospective analysis of specimens from the Microbiology Department and antibiograms.

Results The number of isolates of Proteus mirabilis in 2009 was 358, 218 in 2010 and 168 in 2011. From urine: 130 in 2009, 89 in 2010 and 80 in 2012; from wound smears (decubitus, fistula, ulcers): 349 in 2009, 198 in 2010, 154 in 2011; tracheal swabs: 9 in 2009, 20 in 2010 and 14 in 2011. In the Anaesthesiology Clinic: 19 isolates were found in 2009 and 2010 and 17 in 2011; In the Surgical Clinic: 71 in 2009, 37 in 2010 and 27 in 2011; Paediatrics: 13 in 2009, 18 in 2010 and 12 in 2011; Neurology: 27 in 2009, 18 in 2010, 9 in 2011; Gynaecology: 13 in 2009, 12 in 2010, 11 in 2011; Infectiology: 41 in 2009, 16 in 2010, 8 in 2011; Dermatology: 36 in 2009, 7 in 2010, 3 in 2011, followed by Neurosurgery, Haemodialysis, Gastroenterology, Haematology and other clinics and wards with fewer than ten isolates yearly.

Sensitivity to carbapenems was 100%, to cephalosporins 86% in 2009, 93.7% in 2010, 96.4% in 2011; to penicillins 55% in 2009, 92% in 2010 and 70% in 2011; to fluoroquinolones 80.5% in 2009, 79.3% in 2010 and 89.6% in 2011; to aminoglycosides 81.4% in 2009, 87.68% in 2010, 95% in 2011; to sulfamethoxazole+trimethoprim: 60.7% in 2009, 66.3% in 2010, 65.4% in 2011: to nitrofurantoin: 5.3% in 2009, 5.4% in 2010, 3.6% in 2011.

Conclusions The number of isolates of Proteus mirabilis decreased in the period considered, due to new algorithms and protocols. If not in combination with other microorganisms, Proteus mirabilis is the only indicator of insufficient cleaning.

Sensitivity to penicillins, nitrofurantoin and cotrimoxazole decreased, but increased to fluoroquinolones, aminoglycoside and cephalosporins.

No conflict of interest.