Serratia
S. marcescens species are increasingly resistant to antibiotics, they rapidly acquire resistant genes, which makes the infections difficult to treat. Gentamicin is the common antibiotic that was used to treat S. marcescens infections, however, bacteria became resistant to it. S. marcescens has the ability to produce beta-lactamase, which is the enzyme providing bacteria resistance to beta lactam antibiotics, such as penicillin. Now the treatment is more effective in a combination of different antibiotics5.