Incidence, identification of multidrug-resistant pathogens and impact on the outcome after cardiac surgery

Introduction

Multidrug-resistant (MDR) pathogens constitute an emerging threat with increasing incidence and uncertain outcome. On the other hand, patients undergoing open heart surgery represent a vulnerable population.

Methods

Evaluation of the incidence and identification of MDR pathogens after cardiac surgery in 2,803 patients for a 2-year period. Examination of the clinical features of patients with MDR infection. Elucidation of the impact on the outcome.

Results

In 18 patients (0.64%) consisting of 12 males and six females, at least one MDR pathogen was isolated. Gram-positive pathogen was certified in five patients (27.8%) and Gram-negative in 13 patients (72.2%). Specifically, four patients were infected with vancomycin-resistant enterococcus (VRE), six with Klebsiella pneumoniae, three with Acinetobacter spp., one with VRE and Acinetobacter spp., four with Acinetobacter and K. pneumoniae. Low output syndrome (CI <2.0 l/min/m2) was common in all these patients and essentially contributed to the deterioration of clinical situation with dependence on inotropic support, prolonged mechanical ventilation (>10 days), acute renal failure and need for haemodilution (66.6%). Therefore, the ICU and hospital stay is prolonged (>20 days and >30 days, accordingly) and pathogenesis of MDR infection is provoked after 20 days of ICU stay. Consequently, nine patients with MDR infection (50%) died. All were critically ill patients with multiple organ dysfunction syndrome under broad-spectrum antimicrobials with hospital-acquired bloodstream MDR bacteremia.

Conclusions

Infection with MDR pathogens, while rare, constitutes a notable prognostic marker of increased mortality after cardiac surgery. It is worth noting that the higher mortality rate is mainly attributable to the severe co-morbidity in haemodynamically compromised patients. Management must concentrate on the implementation of effective preventative strategies.