INTRODUCTION

Healthcare-associated infections (HAIs), or previously called hospital-acquired infections (HAIs), represent a range of pathologies that cause high morbidity and mortality rates. These events are most common in critical areas with vulnerable populations, such as a neonatal intensive care unit (NICU), where patients are prone to prolonged hospital stays and invasive procedures, such as catheter insertion (central and peripheral). The use of central catheters in the neonate corresponds to a common practice in medical management ¹. However, being an invasive device, catheters create an entry point for various microorganisms; furthermore, both its placement and maintenance have been associated with cases of superinfection ^{( 2}.

In Peru, epidemiological reports describe important frequency measures of HAIs during the last decades. In 2013, it is described that 12.7% of the 9,812 HAIs occurred in neonatology services ³. Similarly, in 2018, an incidence rate of central line-associated bloodstream infection (CLABSI) of 4.92 was reported, which is higher than other types of HAIs reported in that year ³.

The impact of CLABSI is important for both, patient prognosis and public health ^{4 , 5}. Warren et al. reported that the total hospital costs in neonates who have suffered from this pathology are almost three times those of unaffected neonates ⁴. Nevertheless, it is recognized that preventive interventions can reduce the number of complications ⁶. For this purpose, longitudinal studies are needed to explore the epidemiology of this disease. The aim of this study is to determine the incidence of CLABSI in the NICU of a public hospital in Lima, Peru, and to explore the risk factors associated with this pathology.

THE STUDY

FINDINGS

A total of 167 neonates were included, in which 322 central catheters were placed in 1,999 catheter-days; 47.3% neonates were female. The median GA was 32.3 (SD: 4) vs. 34.6 (SD: 3.5) weeks between the CLABSI and non- CLABSI group (p<0.05). Eighty-two percent were preterm (≤37 weeks) and the median weight at the time of catheter insertion was 1,990 grams (Table 1).

Sixteen cases of CLABSI were diagnosed (9.6% of the total cohort). Thus, the incidence rate was 8/1000 catheter-days. All cases of CLABSI were found in preterm infants and 56.3% of them had a birth weight of less than 1,500 grams. Fifty percent (8/16) were women. Gram-positive bacteria were isolated in 62.5% and gram-negative in 37.5% of the cases. Staphylococcus aureus was the most frequent bacterium (31.3%) (Table 2). Regarding catheter-related variables, 93.8% of participants with CLABSI carried multiple catheters at some time during their stay (50%, 3 catheters; 43.8%, 2 catheters) and the most frequent indication was TPN (81.3%). Regarding the catheter insertion site, 66.7% of the catheters associated with CLABSI were placed via the umbilical route and 33.3% via the peripheral route. The overcrowding control variable was present at some time during the hospital stay in 62.5% of the cases.

In the bivariate analysis, umbilical catheter use (RR: 0.25; 95% CI: 0.09-0.65; p=0.005) and multiple catheter use (RR: 4.98; 95% CI: 2.05-12.12; p<0.001) were shown to be statistically significant factors in the development of CLABSI. Female sex, increased catheter-days, presence of overcrowding and the use of TPN showed an increased risk, but not statistically significant (Table 3).

DISCUSSION

CLABSI is an adverse healthcare event whose magnitude nationwide is partially known, based on the epidemiological surveillance of the Ministerio de Salud (MINSA). However, at the hospital level, its exact incidence is unknown. This study proposes to fill a gap in knowledge by estimating the magnitude of CLABSI in a prospectively enrolled cohort over one year. The incidence rate of CLABSI in neonates admitted to the NICU of a Peruvian public hospital was 8/1000 catheter-days, an incidence higher than that described nationally and internationally ^{( 3 , 14}.

Coinciding with several studies, the microorganisms found were Staphylococcus aureus, followed by coagulase-negative Staphylococcus ¹⁵. Both are frequently found colonizing the skin, the main entry point for this condition ¹⁶. Likewise, only 37.5% of the cases were caused by gram-negative bacteria. This is consistent with studies conducted by the National Healthcare Safety Network in the United States between 2016-2017 where low rates of infection by these bacteria were reported ⁷. The low percentage of cases associated with gram-negative bacteria coincides with the more frequent choice of the head and upper limbs as the site of device insertion rather than the femoral insertion. This location is the most at risk due to its proximity to urinary and fecal flora ¹⁷.

Among the factors associated with CLABSI, gestational age less than 28 weeks and a weight less than 1,500 grams at the time of catheter insertion are identified as important risk factors ¹⁸. In concordance with the reported cases of CLABSI, 100% had a gestational age of less than 37 weeks, although no statistically significant relationship was found regarding weight and the occurrence of CLABSI; despite the fact that both factors are frequently interrelated and represent severe conditions that require greater manipulation of the catheter, a fact that has been associated with bacteremia ¹³.

Regarding catheter-related variables, multiple use and umbilical insertion location were reported as predisposing factors for infection ^{15 , 18 , 19}. In the bivariate analysis, we found that the use of multiple catheters had a statistically significant relationship with the presence of CLABSI. However, contrary to the literature, umbilical insertion was a protective factor, possibly due to the short time of use compared to PICC.

Overcrowding is a measure that reflects the capacity of a hospital to adequately care for its patients ²⁰. We found that 62.5% of the group with CLABSI were in an overcrowded condition at some time during their hospitalization. However, this was not statistically significant in the bivariate model. Previously reported causes are the lower availability of staff per patient and thus a potentially reduced implementation of infection prevention measures ²⁰.

Limitations of our study include the absence of a sample size calculation and the use of an unadjusted bivariate analysis, which could have affected the analysis of the variables; and the single-center nature that affects extrapolation to other contexts. Although, there was difficulty in strictly complying with the microbiological criteria for the diagnosis of CLABSI due to the lack of equipment and personnel, we used the criteria established by the CDC and MINSA, mainly for epidemiological surveillance purposes.

In conclusion, the incidence of CLABSI was 8/1000 catheter-days, a figure higher than what is found in previous reports. This adverse event carries a high burden of morbidity and mortality for those who suffer it. Therefore, prospective multicenter studies with a larger population are proposed to allow the inference of other risk factors and the application of infection control strategies with subsequent measurement of the impact of these interventions on incidence. Finally, although the number of cases was limited, our findings suggest the establishment of an infection control program to reduce risk factors and decrease morbidity.