Epidemiology and Clinical Significance of Blood Cultures Positive for Coagulase-Negative Staphylococcus

Abstract

Coagulase-negative staphylococci are frequently isolated from blood cultures. As these organisms may occasionally cause serious disease, differentiating bacteremia from contamination is very important but often difficult. Over a 26-month period, of 29,542 blood cultures processed at the University of Michigan Medical Center, 2,875 (9.7%) were positive, and of those, 694 (from 527 patients) grew coagulase-negative staphylococci. Isolates from the 439 patients with only one blood culture positive for coagulase-negative staphylococci and those from the 18 patients with two positive cultures 10 days or more apart were deemed contaminants. Review of the records of the remaining 70 patients with multiple isolates indicated that 33 had had an episode of true bacteremia, 29 (87.9%) of which were associated with intravascular catheters or prosthetic valves. Overall, 85% of all coagulase-negative staphylococci isolated during the study period were judged to be contaminants. Seventy-one percent of the blood cultures drawn during the episodes of bacteremia were positive for coagulase-negative staphylococci as opposed to only 34% in the patients with contaminated cultures (p less than 0.01). Moreover, coagulase-negative staphylococci grew in both aerobic and anaerobic bottles in 85% of blood culture sets drawn during episodes of bacteremia, but in only 30% of the cultures thought to be contaminated (p less than 0.001). Growth of coagulase-negative staphylococci in less than 48 hours was also significantly associated with bacteremia (p less than 0.01). Antibiotic sensitivity patterns were not useful in differentiating bacteremia from contamination.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and antimicrobial susceptibility pattern of Coagulase-negative Staphylococcus

“…This study showed that S. epidermidis was the most common CoNS species comprising 43% of all isolates similar to that of other reports [11][12][13][14][15][16] . CoNS was reported as an important cause of blood stream infections and the second most common source after wound swabs in a hospital in Lebanon and Kuwait [17][18] .…”

“…Antimicrobial resisitance pattern to 20 antimicrobial agents were performed Results : Coagulase-negative Staphylococci consisting of 10 different species were isolated. Staphylococcus epidermidis ( 49), Staphylococcus haemolyticus ( 19) , Staphylococcus hominis ( 11) were the most commonly isolated species. Antimicrobial susceptibility pattern revealed that they were all universally sensitive to vancomycin and linezolid.…”

Serum Procalcitonin for Discrimination of Blood Contamination from Bloodstream Infection due to Coagulase-Negative Staphylococci

“…Coagulase-negative staphylococci as ubiquitous skin commensals are both, the most common cause of nosocomial bloodstream infection (BSI) and blood culture contamination [1][2][3]. It is important to distinguish blood contamination from BSI to promptly initiate an adequate therapy in BSI and, in contamination to avoid unnecessary antimicrobial usage and healthcare expenditures, reduce the selection pressure on microorganisms and prevent potential drug adverse events.…”

Comparison of Coagulase-Negative Staphylococci Isolated from Blood Cultures as a True Bacteremia Agent and Contaminant in Terms of Slime Production and Methicillin Resistance

“…In the study of Kirchhoff and Sheagren [10], 85% of all CoNS isolated during the study period were judged to be contaminants. In the present study, 13,268 blood culture samples were examined within the a two-year period, and 947 (7.1%) CoNS were isolated.…”