Serratia marcescens is an opportunistic gram negative bacterium, responsible for 2% of nosocomial infections and bacteremia (yearly incidence, 1.03 per 100,000 population) with high morbidity and mortality especially in Neonatal Intensive Care Units. Diagnosis and treatment often represent a problem for clinicians because of spreading of Multi Drug Resistant Bacterial Strains. This case describes the management of a post-surgery infection by AmpC S. marcescens in a 47 years-old immunocompetent man undergone sternotomy following mitral valvuloplasty. After cardiosurgery treatment, complicated by severe left ventricular heart failure, S.marcescens was isolated in blood samples and quinolones were given. Owing to persistence and in vitro resistance to most β-lactamins of S.marcescens in the surgery wound, the patient was repeatedly treated with targeted therapy including aminoglycosides and quinolones without clinical improvement. The patient was admitted at our Institution for a further exacerbation of sternal infection, with fistula secreting purulent material. Serratia was isolated again. The C-reactive protein was normal. A toracic CT scan showed a sternal mass (foreign body granuloma with dishomogeneous structure of retrosternal soft tissue), while scintigraphy with labeled leukocytes demonstrated the persistence of sternal infectious process without any deep tissues involvement. Microbiological results for Serratia isolates were similar as above, with a good susceptibilty to carbapenems (MIC <=1μg/mL). Ertapenem plus ciprofloxacine administered for 8 weeks with local debridement and removal of a suture string led to a temporary improvement. Because of new exacerbation occurred after several months, we decided to restore ertapenem plus prulifloxacine therapy for further 2 month. This association led to a complete recovery. The follow-up with scintigraphy with labeled leukocytes after 6 and 12 months didn’t show any inflammation process. Management of chronic osteomyelitis represents an important challenge for clinicians. It often occurs without laboratory alterations and can alternate clinically silent periods with new exacerbation phases. A targeted and prolonged antibiotic treatment must be often combined with a surgery debridement considering the frequent formation of biofilm. Serratia osteomyelitis may be commonly caused exogenously by surgery, as our case demonstrated. We suspected AmpC producer Serratia on the basis of its cefoxitine resistance and its eradication with carbapenems and quinolones. Risk factors for severe Serratia infection were not documented in our patient except for cardio surgery treatment. Reports of post-cardiosurgey infections by Serratia are rare. These, however, must be suspected in immunocompetent patients if undergone major surgery. Use of ertapenem, instead of other carbapenems, in combination to prulifloxacine could represent a valid alternative for osteomielitis due to S.marcescens, with once daily administration
Post-Sternotomy Chronic Infection by Serratia Marcescens. Case Report and Literature Review. Pubblicato in Microbiologica, 2011.
GRILLI, Anastasio;Cavallesco G;CONTINI, Carlo
2011
Abstract
Serratia marcescens is an opportunistic gram negative bacterium, responsible for 2% of nosocomial infections and bacteremia (yearly incidence, 1.03 per 100,000 population) with high morbidity and mortality especially in Neonatal Intensive Care Units. Diagnosis and treatment often represent a problem for clinicians because of spreading of Multi Drug Resistant Bacterial Strains. This case describes the management of a post-surgery infection by AmpC S. marcescens in a 47 years-old immunocompetent man undergone sternotomy following mitral valvuloplasty. After cardiosurgery treatment, complicated by severe left ventricular heart failure, S.marcescens was isolated in blood samples and quinolones were given. Owing to persistence and in vitro resistance to most β-lactamins of S.marcescens in the surgery wound, the patient was repeatedly treated with targeted therapy including aminoglycosides and quinolones without clinical improvement. The patient was admitted at our Institution for a further exacerbation of sternal infection, with fistula secreting purulent material. Serratia was isolated again. The C-reactive protein was normal. A toracic CT scan showed a sternal mass (foreign body granuloma with dishomogeneous structure of retrosternal soft tissue), while scintigraphy with labeled leukocytes demonstrated the persistence of sternal infectious process without any deep tissues involvement. Microbiological results for Serratia isolates were similar as above, with a good susceptibilty to carbapenems (MIC <=1μg/mL). Ertapenem plus ciprofloxacine administered for 8 weeks with local debridement and removal of a suture string led to a temporary improvement. Because of new exacerbation occurred after several months, we decided to restore ertapenem plus prulifloxacine therapy for further 2 month. This association led to a complete recovery. The follow-up with scintigraphy with labeled leukocytes after 6 and 12 months didn’t show any inflammation process. Management of chronic osteomyelitis represents an important challenge for clinicians. It often occurs without laboratory alterations and can alternate clinically silent periods with new exacerbation phases. A targeted and prolonged antibiotic treatment must be often combined with a surgery debridement considering the frequent formation of biofilm. Serratia osteomyelitis may be commonly caused exogenously by surgery, as our case demonstrated. We suspected AmpC producer Serratia on the basis of its cefoxitine resistance and its eradication with carbapenems and quinolones. Risk factors for severe Serratia infection were not documented in our patient except for cardio surgery treatment. Reports of post-cardiosurgey infections by Serratia are rare. These, however, must be suspected in immunocompetent patients if undergone major surgery. Use of ertapenem, instead of other carbapenems, in combination to prulifloxacine could represent a valid alternative for osteomielitis due to S.marcescens, with once daily administrationI documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
