The commonly used central venous catheterization may lead to CRBSI, a major and persistent problem in NICU of China [10, 11]. ALT has been successfully employed to prevent CRBSI in adults and children patients [15–17, 23–25], while it has rarely been carried out in neonates [19, 20]. In the present study, we evaluated the efficacy of vancomycin-lock technique in the treatment of VLBW preterm infants who needed long-term retention of PICC catheters in NICU. We showed that the CRBSI incidence rate was significantly decreased in the vancomycin-lock group compared with that in the control group, indicating the preventive role of vancomycin-lock in CRBSI. This study could be clinically used to prevent the incidence of CRBSI during the catheter-retaining process in VLBW infants. Until now, there have no similar results in terms of Chinese VLBW preterm infant patients in NICU yet. This study will be beneficial to the application of ALT for VLBW preterm infant patients in not only Chinese populations but also others.
We showed that Gram-positive bacteria were the major pathogenic microorganisms in CRBSI (66.7%). The Gram-positive coccus are the major types of pathogens in bacteria biofilms [26, 27]. Vancomycin has an inhibitory effect on a variety of gram-positive cocci, particularly bacteria in the inner catheter bacteria biofilm [28, 29], and its efficacy and safety in neonates has been confirmed [30, 31]. Therefore, vancomycin was selected for antibiotic-lock so as to prevent the incidence of CRBSI, which is consistent with some reports using vancomycin as the main locking antibiotic [32–34].
We showed that ALT did effectively reduce the incidence of CRBSI, without obviously causing systemic side effects, which is consistent with Garland et al.’ and Filippi.’ results [19, 20] (Table 5). Interestingly, our result showed a lower infection rate per 1000 catheter-days (1.34‰) in infants receiving ALT when compared with these two studies (2.3‰ and 6.6‰, respectively) [19, 20]. This suggests better efficacy of using ALT to prevent CBRSI in preterm infant patients in our study.
Table 5
Comparison of the present study with Galand et al.’ and Filippi et al.’ results
| Present study | Galand et al.’ study | Filippi et al.’ study |
Gestational age, Wk | 29.7 ± 1.9 | 27.5 ± 3.8 | 29.1 ± 4.8 |
Birth weight, Kg | 1.25 ± 0.18 | 1.06 ± 0.72 | 1.04 ± 0.61 |
PICC time, d | 33.0 ± 12.7 | 20.3 ± 11.4 | 7.5 (2–29) |
CRBSI in AL (n/%) | 4.4% (3/68) | 4.8% (2/42) | 6.0% (3/50) |
CRBSI in C (n/%) | 21.7% (15/69) | 30.2% (13/43) | 24.5% (13/53) |
P value | 0.004 | 0.002 | < 0.01 |
AL, antibiotic-lock group; C, control treatment without antibiotic-lock. P value showed the comparison between the incidence rate of CRBSI in AL and C groups. |
Although ALT could successfully prevent the incidence of CRBSI, we did not observe significant improvement of treatment outcomes such as MV time, PICC days, TPN or PPN days, and hospital stay. Similarly, in a multicentered (14 NICU centers) prospective study Ruth et al. demonstrated that the outcomes were not obviously improved with the reduction of CRBSI rate [35]. Our and Ruth et al.’s results indicate that contribution of ALT to reduce the incidence of CRBSI is independent of improving the treatment outcomes, which might be related to difference in the types and severity of the diseases in infants.
It is necessary to evaluate the side effects of vancomycin on body. In our study, the blood concentrations of vancomycin were measured every 2 weeks. We showed that all the blood vancomycin concentrations were < 3 µg/ml (lower than the minimum detectable limit). Given the total administrated dose of vancomycin (3 times) in the catheter was only 75 µg per day and it was eliminated so completely (even undetectable), it would not accumulate in body to bring about side effects.
We demonstrated that vancomycin-lock significantly reduced the antibiotic exposure time during the catheter retaining, which had been rarely reported. Filippi et al. used amoxicillin or gentamicin in all neonate patients for 10 days, fluconazole for within one month and sodium fusidate for catheter-locking, and found that the systematic antibiotic exposure time was not obviously reduced with the significant decrease of total CRBSI incidence [20]. In contrast, our ALT procedure appears better. We showed that antibiotic exposure time was generally significantly shorter in patients, particularly in non-CRBSI patients (regardless of non-catheter-related infection or non-infection), in the vancomycin-lock group than in the control group. This demonstrates that vancomycin-lock effectively reduces the requirement of systematic antibiotic exposure time in infant patients, which may decrease the accumulation of antibiotics in body and thus avoid the antibiotic-related side effects.
Hypoglycemia is a most concerned side effect during the ALT procedure. The subjects of this study were VLBW preterm infants and they needed continuous infusion of high energy nutrient solution before they could establish intestinal nutrition. During the lock process, we needed to stop the infusion of nutrient solution for 30 min. To prevent the incidence of hypoglycemia, we measured the blood glucose before locking. If the blood glucose concentrations were too low (< 50 mg/dL), the vancomycin-lock procedure was be postponed. Therefore, there were no hypoglycemic events observed.
In our study, vancomycin was used as the locking drug, with strong pertinence and small resistance. Vancomycin-lock could obviously reduce the bloodstream infection of Gram-positive cocci but failed to control that of Gram-negative bacilli. This might be related to its nature as a limited-spectrum antibiotic. Gram-negative bacteria-induced CRBSI may involve a more complex pathogenesis and prevention strategy [36]. Daptomycin has been recently recommended for its strong penetration [37–39]. Next, vancomycin will be combined with daptomycin or other antibiotics to be used as lock solution for preterm infant patients to achieve better outcomes.
There are several limitations in this study. This was a retrospective study that there might be bias in the selection of cases and incompletion of clinical information. In addition, the sample size of this study was not large. A prospectively, multicentered, randomized, controlled, and double-blinded trial with more preterm infant patients is warranted to validate this result.