Background: Coagulase-negative staphylococci (CoNS) are the most commonly isolated bacteria from blood cultures and the most considered contaminants. We conducted a study to assess clinical and laboratory indicators predicting CoNS as a cause of bloodstream infections using two sets of blood cultures among under-five children in Dar es Salaam, Tanzania. In addition, we determined the antimicrobial susceptibility patterns of CoNS.
Materials and methods: This cross-sectional study involved 246 children clinically diagnosed with bloodstream infections admitted to a tertiary hospital . Two sets of blood cultures were collected per patient. Blood samples were tested for microbial growth and antimicrobial susceptibility. Indicators independently predicting CoNS as a cause of bloodstream infection were calculated by binary logistic regression analysis, receiver operating characteristic (ROC) curve analysis to assess the diagnostic performance of predictors. A p-value <0.05 at 95% confidence intervals was considered significant.
Results: Of 246 patients, 100(40.7%) were positive blood cultures. CoNS were the most prevalent, isolated in 51(51.0%) blood cultures. Of 51 blood cultures with CoNS, 40(78.4%) were isolated in both blood culture bottles of a set and were regarded as causative of bloodstream infection,of this 34(85.0%) were methicillin resistance CoNS. Multivariate analysis identified tachycardia (aOR = 14.69, 95%CI 1.36-158.42, p = 0.027) and in situ intravenous cannulation (aOR = 66.75, 95%CI 3.61-1234.40, p = 0.005) as significant predictors of CoNS bloodstream infection, with a prediction score of 94.1%. The ROC curve analysis demonstrated tachycardia and in situ intravenous cannulation had AUC > 0.7 (p < 0.05). The CoNS were frequently resistant to penicillin (97.5%), erythromycin (82.5%), and trimethoprim-sulfamethoxazole (77.5%).
Conclusions: CoNS remains the most common bacteria causing bloodstream infections. In situ intravenous cannulation and tachycardia were potential clinical indicators in improving early diagnosis of CoNS as a cause of bloodstream infections and guiding timely treatment decisions. High antimicrobial resistance observed necessitating strengthening of antimicrobial stewardship.
Keywords: Clinical indicators; antimicrobial resistance; bloodstream infection; coagulase-negative staphylococci; laboratory indicators; under-five children.