Infect Drug Resist. 2020 Sep 7;13:3091-3101. doi: 10.2147/IDR.S259914. eCollection 2020.
INTRODUCTION: Febrile neutropenia (FN) is the evolution of fever in a patient with neutropenia over 38.0°C. Neutropenia is diagnosed when absolute neutrophil count (ANC) <1500 cells/µL. FN represents a common complication of cancer treatment. Hence, it is featured to be a major cause of morbidity and mortality in cancer patients. Staphylococcus aureus is one of the most important microorganisms isolated from the blood of febrile neutropenic patients. Infections caused by S. aureus range from mild to life-threatening diseases. Biofilm production by S. aureus is one of the most significant virulence factors of the bacterium as it prevents the penetration of antibiotics. Recently, it has been shown that S. aureus carries the ica operon responsible for biofilm production. The aim of the work is to determine a genotypic characterization that includes not only the detection of icaA and icaD genes in S. aureus but also the determination of their relation to clinical and microbiological features. Empiric antibacterial treatment was recommended for cancer patients receiving chemotherapy.
MATERIALS AND METHODS: The relation between the presence of icaA and icaD and biofilm production was determined in a collection of 66 S. aureus samples from febrile neutropenic patients. Biofilm-forming ability was tested on Congo Red agar plates. Also, the effect of the most sensitive antibiotics on the bacterial cells was determined by an electron microscope.
RESULTS: Of the bacterial samples, 48 were biofilm-productive and 18 were non-biofilm productive. For the biofilm productive bacteria, 37.5% were positive for icaA, 22.9% were positive for icaD and 10.4% were positive for both. Linezolid was the most effective antibiotic and it is highly recommended for the treatment of febrile neutropenia caused by biofilm-productive S. aureus. Severe changes were found on the bacterial cell after being treated with Linezolid. The icaA and icaD genes were present in only 50% of biofilm-productive bacteria.
CONCLUSION: The ica operon is present in only 50% of biofilm-productive S. aureus and Linezolid is the best antibiotic against these bacteria.