A 62-year-old man with long-standing type 2 diabetes mellitus secondary to chronic calcific pancreatitis with a tendency to hypoglycaemia due to the administration of rapid insulin, multiple admissions for urinary infectious conditions and functional deterioration.

On admission, he suffered from neglect of personal hygiene with uncontrolled elimination habits, malnutrition, chronic renal failure, diabetic ketoacidosis and a grade III sacral ulcer.

Culture of the ulcer exudate showed that it was positive for MRSA and methicillin-resistant Staphylococcus aureus (MRSA) and the antibiogram showed that MRSA was sensitive only to colistin (MIC < 2) and intermediate to amikacin (MIC = 16). MRSA was sensitive to co-trimoxazole (MIC < 1/19) and intermediate to clindamycin (MIC = 1.9).

Treatment was initiated with colistin cream 0.1% with daily application to the dressing and oral cotrimoxazole 800/160 mg every 12 hours for MRSA treatment. After one month of treatment, a favourable clinical evolution of the ulcer was observed, with growth of edges and granulation tissue, which had not been observed prior to topical treatment.

The patient died due to chronic renal failure exacerbated by urinary sepsis, for which reason a post-treatment culture was not available.