BackgroundPost-neurosurgical intracranial infections caused by multidrug-resistant or extensively drug-resistant Acinetobacter baumannii are difficult to treat and associated with high mortality. In this study, we analyzed the therapeutic efficacy of intravenous combined with intrathecal/intracerebral ventricle injection of polymyxin B for this type of intracranial infection.MethodsThis retrospective study was conducted from January 2013 to September 2017 at the Second Affiliated Hospital, Zhejiang University School of Medicine (Hangzhou,China) and included 61 cases for which cerebrospinal fluid (CSF) cultures were positive for multidrug-resistant or extensively drug-resistant A. baumannii after a neurosurgical operation. Patients treated with intravenous and intrathecal/intracerebral ventricle injection of polymyxin B were assigned to the intrathecal/intracerebral group, and patients treated with other antibiotics without intrathecal/intracerebral injection were assigned to the intravenous group. Data for general information, treatment history, and the results of routine tests and biochemistry indicators in CSF, clinical efficiency, microbiological clearance rate, and the 28-day mortality were collected and analyzed.ResultsThe rate of multidrug-resistant or extensively drug-resistant A. baumannii infection among patients who experienced an intracranial infection after a neurosurgical operation was 33.64% in our hospital. The isolated A. baumannii were resistant to various antibiotics, and most seriously to carbapenems (100.00% resistance rate to imipenem and meropenem), cephalosporins (resistance rates of 98.38% to cefazolin, 100.00% to ceftazidime, 100.00% to cefatriaxone, and 98.39% to cefepime). However, the isolated A. baumannii were completely sensitive to polymyxin B (sensitivity rate of 100.00%), followed by tigecycline (60.66%) and amikacin (49.18%). No significant differences in basic clinical data were observed between the two groups. Compared with the intravenous group, the intrathecal/intracerebral group had a significantly lower 28-day mortality (55.26% vs. 8.70%, P = 0.01) and higher rates of clinical efficacy and microbiological clearance (95.65% vs. 23.68%, P < 0.001; 91.30% vs. 18.42%, P < 0.001, respectively).ConclusionsIntravenous plus intrathecal/intracerebral ventricle injection of polymyxin B is an effective regimen for treating intracranial infections caused by multidrug-resistant or extensively drug-resistant A. baumannii.

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To the Editor: Despite major advances in medical care, the incidence and mortality of bloodstream infection (BSI) remain high, which is still a global public health challenge. BSI can be caused by various microorganisms, and the most common organisms are Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus (S. aureus), according to the China Antimicrobial Surveillance Network (CHINET). [1] S. aureus is the third most common cause of BSI, which is associated with shortterm mortality rates of 15-30%, long-term excess mortality, and increased healthcare costs. At present, there are many studies on Gram-negative bacteremia but relatively few on S. aureus bloodstream infection (SA-BSI), especially in China. With the occurrence of new treatments and clinical conditions, such as aging and extensive antibiotic resistance, it is necessary to reanalyze the clinical characteristics and prognosis of SA-BSI. This single-center retrospective cohort study was conducted in the Second Affiliated Hospital, Zhejiang University School of Medicine. The Ethics Committee of our hospital granted ethics approval (No. 2019-194) for the present study. The requirement for signed informed consent was exempted because of the retrospective nature of the study. Furthermore, a statement of permission from patients for submission was not needed, as no personal information was included.