Pseudomonas aeruginosa (PA) is a common gram-negative bacterium. Imipenem (IMP) is considered to be the most effective clinical drug for the treatment of PA infection. IMP-resistant ceftazidime-susceptible PA is relatively rare in clinical practice; so far, there have been no clinical reports regarding the treatment of IMP-resistant PA with piperacillin/tazobactam alone. This paper will report the case of a severe pneumonia patient with IMP-resistant ceftazidime-susceptible PA infection that was successfully treated with piperacillin/tazobactam monotherapy after initial therapy with biapenem (BIP) according to the drug sensitivity test. The patient was a 75-year-old female, her main symptom was drowsiness. She was admitted to hospital due to acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and pulmonary encephalopathy. After admission, endotracheal intubation was performed immediately, and the lavage fluid was sent to the laboratory for sputum culturing for several times. BIP was selected for the initial anti-infection regimen, and other symptomatic treatments were performed at the same time. On the day 8, the sputum culture drug sensitivity test results showed PA (sensitive to: piperacillin/tazobactam sodium, ceftazidime, aminoglycoside, and fluoroquinolones; resistant to IMP; and intermediate sensitivity to: cefoperazone-sulbactam and meropenem), so we adjusted the anti-infection regimen as piperacillin/tazobactam sodium. After that, the infection index of the patient declined steadily, and the patient was discharged from hospital after continuous treatment with piperacillin tazobactam until the 24th day. For severe pneumonia patients with IMP-resistant ceftazidime-susceptible PA infection, piperacillin/tazobactam is still an option specially when the MIC of piperacillin/tazobactam is very low.
Keywords: Pseudomonas aeruginosa (PA); carbapenem resistance; case report; ceftazidime susceptible; piperacillin/tazobactam.