Phagoburst Response Level of Neutrophils to Septic and Non-Septic Acinetobacter baumannii Isolates
Open Microbiology Journal
Acinetobacter baumannii is an opportunistic pathogen causing community-acquired and nosocomial infections. Dissemination of infection to blood causes septicemia associated with serious morbidity and mortality of patients. Neutrophils are essential for the control of A. baumannii infections by different mechanisms, including oxidative burst. Aims: This study was conducted as an attempt to determine the effect of septicemic and non-septicemic A. baumannii isolates on the phagoburst response of
... trophils. Methods: Neutrophils were isolated from an immunocompetent individual; chronic myeloid leukemia (CML) and lung solid tumor (ST) patients. The phagoburst response of these neutrophils to various strains of A. baumannii isolated from septic and non-septic patients was investigated by flow cytometer. Results: The presence of this pathogen lowered the phagoburst response in the different types of neutrophils compared to their response to the opsonized Escherichia coli. The phagoburst response of the neutrophils from the immunocompetent individual was significantly higher than that of neutrophils from the immunodeficient patients when stimulated by the septicemic or nonsepticemic A. baumannii isolates. The isolate type (septicemic or non-septicemic) had no significant effect on the neutrophil phagoburst response of the immunocompetent individual and a significant effect on the phagoburst response of neutrophils from the immunodeficient patients. The phagoburst response of the neutrophils from the immunodeficient patients stimulated by septicemic A. baumannii isolates was significantly lower than that when neutrophils stimulated by the nonsepticemic isolates. Also, there was a significant difference in the phagoburst response of neutrophils from the CML and ST patients when stimulated by the septicemic and non-septicemic isolates. This observation might be due to the combined effect of virulent A. baumannii isolates and the chemotherapy regime the patient was undertaking. Conclusion: The results suggest that both the isolate type and the source of neutrophils have a significant effect on the neutrophil phagoburst response. The potential virulence of the septicemic A. baumannii isolates and dissemination to blood may be dependent on the host's immune status and the neutrophils phagoburst response.