Value of Time to Positivity of Blood Culture in Children with Bloodstream Infections

Abstract

Objective This study was to investigate the microbiological characteristics and the relationship between the time to positivity (TTP) of blood cultures and different bacterial species and to assess the clinical value of TTP in children with bloodstream infections (BSIs). Methods The TTP of all the blood cultures from children with suspected BSIs was retrospectively collected in 2016. The microbiological characteristics and the relationship between the TTP of blood cultures and different bacterial species were also analyzed. Results A total of 808 strains were isolated from 15835 blood cultures collected, and 145 (17.9%) were Gram-negative, 636 (78.7%) were Gram-positive, and 27 (3.3%) were fungi. The bacteria were divided into definite pathogens (174), possible pathogens (592), fungi (27), and contaminants (15). The average TTP of all positive blood cultures was 30.97 and ranged from 3.23 h to 92.73 h. The TTP of Gram-negative strains was significantly shorter than that of Gram-positive strains (P < 0.001) and fungi (P = 0.032). The mean TTP for E. coli (15.60 h) was shortest within the group of Gram-negative isolates, and the mean TTP for Streptococcus (17.34 h) within the group of Gram-positive isolates. Significant difference of the TTP was detected in methicillin-resistant vs methicillin-susceptible S. aureus, extended-spectrum beta-lactamases (ESBLs) positive vs negative Enterobacteriaceae, and extensive drug-resistant and non-XDR A. baumannii. The median TTP in patients with BSI was significantly shorter than in those without it (P < 0.001). ROC curve analysis indicated that the TTP cutoff value of CoNS, S. aureus, E. coli, and K. pneumoniae was 22.72 h, 19.6 h, 18.58 h, and 16.43 h, respectively, with most sensitive and specific predictor of BSIs. Conclusions Our data acknowledged that TTP is a valuable index for the early prognosis of BSIs. TTP not only provides additional utility as a general predictor of bacteria with smear result but also provides the implication of drug-resistant organisms.

Evaluation of time to positivity for blood culture combined with immature granulocytes, neutrophil‐to‐lymphocyte ratio, and CRP in identifying bloodstream coagulase‐negative Staphylococci infection in pediatric patients

“…Up to now, many studies in the literature have reported that TTP has a certain predictive value for the clinical significance of CoNS in blood culture, 2,3,8 which is also confirmed by the results of this current study by our group. Zhang Yu et al studied 160 children and found that the optimal critical value for TTP that could be used to determine a child's blood flow infection and contamination was 17.35 hours.…”

“…Studies from Ireland showed that the TTP of all pathogens of bloodstream infections was <24 hours 8 . A more recent study by Pan et al, gave a TTP of 22.72 hours 2 . American Pardo believed that there was almost no real blood stream infection detected after 48 hours of culture, so it was recommended that antibiotic use should be downgraded after 48 hours, which was also verified in the study of Abdelhamid 6,9 .…”

“…As a common parameter in blood culture, the clinical predictive value of time to positivity (TTP) on bloodstream infection has also attracted increased attention 2,3 . TTP refers to a period of time from the moment the blood is isolated from the body to the positive alarm of the blood culture instrument.…”

Bacteriological profile and antibiogram of blood culture isolates from paediatric patients with special reference to ESBL and MRSA in a tertiary care centre

“…Physical signs and symptoms, though useful in identifying possible cases, have limited specificity in diagnosis. 6,7 Growing resistance to conventional and even newer antibiotics is also a matter of serious concern. 17 Blood culture plays an important role by timely and correctly identifying the underlying pathogens and based on their drug resistance patterns guide the clinicians regarding the empirical as well as the definitive treatment.…”

“…4 Blood culture remains the gold standard for laboratory diagnosis of bloodstream infections (BSIs) in infants and children. 5,6 Although both Gram negative and Gram positive bacteria are associated with these infections, Gram negative bacterial infections are more fatal and cause more serious therapeutic problems as multi drug resistant strains are more common among them. [7][8][9] In almost all cases, empiric antimicrobial therapy is initiated before the results of blood culture are available.…”