Use of Antimicrobial Lock Therapy for the Treatment of Central Line-Related Blood-Stream Infections: A Case Series

Introduction: Central line-related blood-stream infections (CLRBSI) represent a major complication of severely ill neonates. Central venous catheter (CVC) removal is recommended when CLRBSI develops. Nevertheless, the placement of a new CVC might be challenging in extremely sick neonates. When the removal of the catheter is not feasible for clinical reasons, a lock therapy (LT) can be used to treat the biofilm that develops in the catheter during a CLRBSI. However, only poor data exist about LT use in neonates.

Materials and Methods: To assess LT safety and efficacy in critically ill neonates, during CLRBSI, we performed daily LT with a volume equal to the CVC priming volume (0.3 mL both for Broviac and Vygon catheters) + 0.2 mL. After drug instillation, CVC remained closed for at least 6 hours and up to 24 hours when possible. The optimal drug for LT was identified according to the antibiogram of the hemoculture. Furthermore, we performed meropenem stability testing to use it for a LT, since no data existed in the literature.

Results: LT was performed in 11 severely ill neonates with CLRBSI. Neonates receiving LT had a Broviac catheter in 10 cases and a Vygon catheter in one case. Blood cultures were positive for Klebsiella pneumoniae in six cases, Candida albicans in four cases, and Enterococcus faecalis in one case. LT was performed for at least 3 and, if possible, up to 10 consecutive days. Overall, LT was performed with amikacin (3 mg/mL) in three cases, micafungin (5 mg/L) and ethanol 70% in four cases, vancomycin (3 mg/mL) in one case, and meropenem in three cases. No mechanical malfunctioning of the CVC was recorded after LT. Infection resolution, with negative control bloodstream cultures, was achieved in 9 out of 11 cases. LT failure, leading to CVC removal, was recorded only in 2 out of 11 cases in which LT was possible for only 3 consecutive days and for only 6 hours due to neonates’ critical conditions.

Conclusion: LT was feasible, was not associated to CVC malfunctioning, was successful in the majority of cases, that is, if applied for several consecutive days and for more than 6 hours/day. We suggest meropenem can be used to lock the catheter. Further investigations are required to confirm LT actual efficacy and safety in neonates and to design with higher accuracy the optimal posology to be used.

Keywords: lock therapy, neonate, CLRBI