Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Dec;8(6):366-371.

Significance of coagulase negative Staphylococcus from blood cultures: persisting problems and partial progress in resource constrained settings

Shailpreet K Sidhu  1 , Sita Malhotra  1 , Pushpa Devi  1 , Arpandeep K Tuli  1
Affiliations

Significance of coagulase negative Staphylococcus from blood cultures: persisting problems and partial progress in resource constrained settings

Shailpreet K Sidhu et al. Iran J Microbiol. 2016 Dec.

Abstract

Background and objectives: Coagulase negative Staphylococcus (CoNS) is frequently isolated from blood cultures but their significance is difficult to interpret. CoNS bacteria which are often previously dismissed as culture contaminants are attracting greater importance as true pathogens in the past decades. Clinical evaluation of these isolates suggests that although there is a relative increase of CoNS associated bloodstream infections in recent years, the microorganisms still remain the most common contaminants in blood cultures. The objective of this study was to determine the significance of CoNS isolated from blood cultures.

Materials and methods: A retrospective study was conducted to evaluate the rate of contamination in blood cultures in a tertiary care hospital. The paired specimens of blood were cultured using conventional culture methods and the isolates of coagulase negative staphylococci were identified by standard methodology. Clinical data, laboratory indices, microbiological parameters and patient characteristics were analyzed.

Results: Of 3503 blood samples, CoNS were isolated from blood culture of 307 patients (8.76%). The isolates were reported as true pathogens of bloodstream infections in only 74 out of 307 cases (24.1%). In the vast majority, 212 of 307 (69.0%), they were mere blood culture contaminants and reported as insignificant/contaminant.

Conclusion: Determining whether a growth in the blood culture is a pathogen or a contaminant is a critical issue and multiple parameters have to be considered before arriving at a conclusion. Ideally, the molecular approach is for the most part a consistent method in determining the significant isolates of CoNS. However, in countries with inadequate resources, species identification and antibiogram tests are recommended when determining significance of these isolates.

Keywords: Bloodstream infections; Coagulase negative Staphylococcus; Contaminants.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Weinstein MP. Blood culture contamination: persisting problems and partial progress. J Clin Microbiol 2003; 41: 2275–2278. - PMC - PubMed
    1. Richter SS, Beekmann SE, Croco JL, Diekema DJ, Koontz FP, Pfaller MA, et al. Minimizing the workup of blood culture contaminants: implementation and evaluation of a laboratory-based algorithm. J Clin Microbiol 2002; 40: 2437–2444. - PMC - PubMed
    1. Mirrett S, Weinstein MP, Reimer LG, Wilson ML, Reller LB. Relevance of the number of positive bottles in determining clinical significance of coagulase-negative staphylococci in blood cultures. J Clin Microbiol 2001; 39: 3279–3281. - PMC - PubMed
    1. Thylefors JD, Harbarth S, Pittet D. Increasing bacteremia due to coagulase-negative staphylococci: fiction or reality? Infect Control Hosp Epidemiol 1998; 19: 581–589. - PubMed
    1. Malik S, Ravishekhar K. Significance of coagulase negative staphylococcus species in blood culture. J Clin Diagn Res 2012; 6: 632–635.

LinkOut - more resources