This study was carried out on 76 patients admitted to pediatric departments in Benha University Hospital and Benha Specialized Hospital for Children. All had prolonged vascular catheterization (> 12 hours). They were 40 (52.6%) males, and 36 (47.4%) females, and their age ranged from 3 days to 10 years (mean = 13 5.67 months). They were classified into 3 groups (a) 26 patients admitted to pediatric ward (b) 13 patients admitted to intensive care unit (ICU) (c) 37 patients admitted to neonatal ICU (NICU). Vascular catheter tips and blood samples were collected from each patient under complete asceptic conditions. Vascular catheter tips were cultured using the semiquantitative culture method, then stained by acridine orange (AO) followed by Gram stain. The blood samples were used for blood culture. The isolated organisms were identified in a systemic way and culture & sensitivity was done for each isolate. Isolated staphylococci were tested for biofilm production by both Congo red agar plate method and tube method.
The results showed that out of 76 catheter tips 45 (59.2%) were positively colonized where as 22 blood culture only were positive 14 of them were catheter related and 8 were catheter unrelated. By analyzing the different risk factors, the study showed that the rate of catheter colonization decreases with increase in age and majority of catheter related blood stream infections (CRBSI) were found in infants less than one month old (25%). Also there was a statistical significant effect of weight on CRBSI, as the incidence of CRBSI increases with decrease in weight (P< 0.05). Regarding the type of catheter the central venous catheters (CVCs) have the highest rates of colonization and bacteremia. In CRBSI the rate was 33.3% in CVCs compared to 20.8% in umbilical catheters and 0% in peripheral catheters, a difference which is statistically significant (P< 0.05). The number of attempts at insertion site has a statistically significant effect on colonization of peripheral catheter only (P< 0.01) as more colonization occurs with increase number of attempts. The duration of catheter insertion has a statistically significant effect on colonization of all catheter types and their related bacteremia. Catheter insertion in the lower limbs carries a high risk for catheter colonization (87.5%) than other sites of peripheral catheter insertion (P < 0.05). The highest rate of catheter colonization and CRBSI occurred in NICU (67.6% and 29.7% respectively), and preterm babies are at great risk for colonization (88.5%). Coagulase negative staphylococci (CNS) was the most frequently isolated organism from catheter tips (33.3%) while Pseudomonas aeruginosa was the commonest organism isolated from CRBSI (42.9%). Ciprofloxacin was the most effective antibiotic
Direct catheter staining by both acridine orange and Gram stain showed low sensitivity (67% and 41% respectively) and low specificity (73% and 82% respectively). Out of 20 isolated staphylocci 15 were biofilm producer as detected by congo red agar plate method compared to 14 by tube method. There was a very good agreement between the 2 methods.
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