The central nervous system infections are a serious group of infections that cause morbidity and mortality, and this can be prevented with early and appropriate antibiotic therapy. Empirical antibiotic treatment is started according to the results of the CSF microbiological examination, infection parameters, and culture results . Serum inflammatory markers that make up the SII are parameters that can be easily obtained in clinical practice. SII has been shown to have a prognostic value in various studies [7, ]. However, no study has investigated the relationship between SII and bacterial agents in catheter-related infections. In the present study, the relationship between SII and possible bacterial agents was evaluated, aiming to provide appropriate antibiotic therapy by determining the parameters at the time of application and possible factors before the culture results were obtained. At the same time, the prognostic effect of SII among bacterial groups was evaluated.
Catheter-related central nervous system infections, especially V-P shunt infections, are more common in the pediatric age group . CSF biochemical examination together with clinical findings can be useful in the diagnosis of central nervous system infections. Moreover, a central nervous system infection is characterized by a white blood cell count of > 10/mm3, decreased glucose level (< 45 mg/dL), and high protein level (> 100 mg/dL) in CSF . In the present study, CSF WBC was determined as 1970.45 ± 5993.39/mm3 (50-27249), CSF glucose 28.36 ± 21.79 mg/dL (1–91), and CSF protein 3887.96 ± 5296.28 mg/dL (4-20723). The lowest CSF glucose level and simultaneous CSF/blood glucose ratio were observed in the non-CNS gram-positive bacteria group, whereas the highest CSF glucose level and simultaneous CSF/blood glucose ratio were observed in the CNS group, indicating a statistically significant difference (p = 0.009–0.046.)
Shunt infections are associated with a high revision rate, recurrent infections, ventriculitis, meningitis, encephalitis, and increased mortality . They include shunt removal, EVD insertion, and antibiotic therapy . Complications include decreased intelligence quotient and increased risk of seizures due to neuronal damage and infection . The most common causative agent in shunt infections is CNS, which is found in the skin flora . CNS constitutes 50% and S. aureus 25% of the bacterial agents . Gram-negative bacteria are less common bacteria, whereas Pseudomonas spp., Klebsiella spp., and Acinetobacter spp. are common bacteria . The risk factors for the development of EVD-associated infection are blood mixing in CSF, CSF sampling frequency, CSF leakage at the drainage entry site, and possibly bilateral drainage . Younger age (< 1 year and prematurity), decreased skin integrity, and intraventricular hemorrhage in children increase the risk of EVD-associated infection compared with adults [5, 19]. The most common factors of EVD catheter-related infection are CNS, S. aureus, and gram-negative bacteria, i.e., E. coli, Acinetobacter spp., and Klebsiella spp.5. In the present study, CNS was the most common, followed by Klebsiella pneumoniae, Enterococci, S. aureus, Acinetobacter baumannii, Pseudomonas aeruginosa, and Serratia marcescens, respectively. The rate of gram-positive bacteria was 67.9%, whereas the rate of gram-negative bacteria was 32.1%.
SII is widely used in various tumors as a prognostic indicator . An increased level of SII is associated with a poor prognosis . In the present study, the effect of SII on prognosis in the bacterial group was examined. It was found that the SII was not predictive in distinguishing between gram-negative and -positive bacteria.
CNS is a group of bacteria found in the skin mucosa, which is considered apathogenic in healthy individuals. However, it is a common cause of hospital infections and catheter-related infections. It usually presents as subacute and chronic infections that start subclinically. However, it can have an aggressive course and be fatal in those who are inadequately treated. It should be considered in the foreground in foreign body-related infections . It was determined that the SII was significantly increased in the gram-positive bacteria group without CNS (p = 0.002). However, in the non-CNS gram-positive bacteria group, an inverse correlation was found between mortality and SII, which was not statistically significant. However, it was observed that the increased SII was significantly associated with mortality in the CNS and gram-negative bacteria groups (p < 0.05). Gram-negative bacteria and CNS usually cause benign and slow infections. The fact that the SII was higher in the gram-negative bacteria and CNS patients with mortality than in survivors may be due to the more severe and progressive gram-negative infections in the mortality group. Moreover, the reason why SII was not different between survivors and patients with mortality in the non-CNS gram-positive bacteria group and the SII was higher compared with the other groups may be due to the fact that these infections were more aggressive and rapid.
Antibiotic resistance changes the treatment response and modalities. While methicillin resistance is prominent in both CNS and S. aureus, broad-spectrum beta-lactamase resistance and carbapenem resistance cause problems in gram-negative bacteria . In the present study, the rate of resistance to any antibiotic was found to be 72.3%, with methicillin resistance being the highest (28.5%). While methicillin resistance was 52.2% in CNS, it was 26.7% in non-CNS gram-positive bacteria. Although the rate of methicillin resistance has been increasing , it was detected at a lower rate in the present study. ESBL resistance was found to be 16.7% in gram-negative bacteria. Clindamycin and quinolone had been found to be highly resistant.
In conclusions, early and appropriate antibiotic therapy reduces morbidity and mortality in catheter-related infections. However, it is very important to start empirical antibiotic therapy until the culture results are determined. Therefore, further research on the estimation of possible factors is important. In the present study, it was determined that the level of SII upon admission was mostly parallel with non-CNS gram-positive bacteria. However, high SII upon presentation was associated with poor prognosis and increased mortality in both the CNS and gram-negative bacteria groups. Furthermore, no bacterial difference was observed in the shunt or EVD-related infections.