Pathogen Analysis of Central Nervous System Infections in a Chinese Teaching Hospital from 2012–2018: A Laboratory-based Retrospective Study Summary Central nervous system (CNS) infections are associated with high mortality rates. The clinical presentation of many CNS infections by different pathogens is difficult to distinguish, but the definite diagnosis of the etiology is critical for effective therapy and prognosis. The aim of this study was to explore the etiology of CNS infections with definite diagnoses based on data from a clinical microbiology laboratory in Tongji Hospital, a teaching hospital in China, obtained over a six-year period. We conducted a retrospective study on all cerebrospinal fluid (CSF) specimens submitted to our clinical microbiology laboratory from September, 2012 to December, 2018. The etiology of CNS infections caused by Cryptococcus neoformans, Mycobacterium tuberculosis and common bacteria was analyzed. Antimicrobial susceptibility testing was conducted on all isolates. The results showed that 1972 cases of CNS infections were identified from 18 300 CSF specimens. Common bacterial meningitis (BM), cryptococcal meningitis (CM) and tuberculous meningitis (TM) accounted for 86.3% (677/785), 9.4% (74/785) and 4.3% (34/785) respectively of cases over the six-year period. BM was the most common among the different age groups, followed by CM. Of the TM cases, 44.1% (15/34) were distributed within the age group of 15–34 years, whereas for CM cases, 52.7% (39/74) occurred within the 35–54-year age group, and the age distribution of BM cases was fairly even. Among the bacterial pathogens isolated, Staphylococcus epidermidiswas the most common, accounting for 12.5% (98/785), followed by Acinetobacter baumannii (ABA) and Staphylococcus aureus (SAU), accounting for 11.8% (93/785) and 7.6% (60/785) respectively. The resistance rates to antibiotics were >75%, with the exception of the resistance rate of ABA to tegafycline, which was <3%. More than 60% of SAU strains displayed resistance to penicillin, oxacillin, ampicillin/sulbactam, cefazolin, cefuroxime, gentamycin, tobramycin, erythromycin and levofloxacin, whereas more than 90% of SAU strains showed susceptibility to trimethoprim/sulfamethoxazole, tegafycline, vancomycin, teicoplanin and linezolid. For C. neoformans, the susceptibility rates to amphotericin B, 5-fluorocytosine, fluconazol and voriconazole were >95%. Analysis of samples from patients with CNS infection in a clinical microbiology laboratory at a teaching hospital in China over a six-year period indicated that the most common etiological agents were the bacteria ABA and SAU. The antibiotic resistance levels of ABA were found to be high and of concern, whereas isolates of C. neoformans were found to be sensitive to antifungal antibiotics.