Objective Coagulase-negative staphylococci (CoNS) are one of the major opportunistic pathogens and the incidence of CoNS bacteraemia is increasing. However, most of the CoNS-positive blood cultures are contaminants rather than true CoNS bacteraemia. In order to minimize contamination, we defined true CoNS bacteraemia as the patient that has two or more identical CoNS-positive blood cultures drawn within 48 h in this study and the objective of this study was to analyse the species distribution and antibiotic resistance and to identify risk factors for 30-day mortality of the true CoNS-bacteraemia. Method By reviewing the electronic medical database, this study retrospectively analysed patients diagnosed as CoNS bacteraemia by blood cultures in a comprehensive tertiary care hospital in China from January 1, 2014, to December 31, 2017. Result A total of 1241 patients with 1562 episodes of CoNS-positive blood cultures were recorded in the database but only 157 patients were finally diagnosed as true CoNS bacteraemia after contaminants were excluded. All these 157 patients (12.7%, 157/1241) had bacteraemia-related clinical symptoms. Among the 157 patients, the most common species were Staphylococcus hominis (40.8%), Staphylococcus epidermidis (36.3%) and Staphylococcus capitis (11.5%). The antimicrobial susceptibility tests showed that all CoNS had a high rate of resistance to penicillin (94.9%), oxacillin (93.6%) and erythromycin (92.4%). Resistance to gentamicin (22.3%) and rifampicin (10.8%) was low, and none of the bacteria were resistant to vancomycin or linezolid. The 30-day mortality of patients with CoNS bacteraemia was up to 12.7% (20/157), and the multivariate logistics regression analysis showed that chronic renal failure (OR 5.9, 95% CI 1.6–21.5, p = 0.007) and chronic liver failure (OR 4.0, 95% CI 1.2–13.1, p = 0.024) were both the significant independent risk factors for the 30-day mortality of CoNS bacteraemia. Conclusion Staphylococcus hominis and Staphylococcus epidermidis were the most common species in CoNS bacteraemia. All CoNS had high multi-drug resistance, but gentamicin and rifampicin had a relatively lower resistance and could be considered as alternative antibiotics for anti-CoNS bacteraemia in addition to vancomycin and linezolid. Additionally, patients with chronic renal failure or chronic liver failure have a higher 30-day mortality after the onset of CoNS bacteraemia.

Significance and impact of the study: We isolated a heterogeneous vancomycin (VAN)-intermediate Staphylococcus aureus (hVISA) strain, and we demonstrated that the cell wall of the hVISA strain was significantly thicker than that of ordinary MRSA strains. The upregulated expression of glmS, vraR/S, sgtB, murZ and PBP4 genes related to cell wall synthesis might be the molecular mechanism underlying the cell wall thickening of the hVISA strain and might be related to its reduced sensitivity to VAN. These results could be used as a supplement to other hVISA-related studies in the world and might be beneficial to prevent and control the emergence of more hVISA.

Over the past few decades, understanding of the clinical features of pulmonary cryptococcosis (PC) has progressed, yet there is a lack of data on the manifestations of PC over time. To investigate the differences in clinical characteristics of PC across different time periods, we performed a retrospective review of 130 non-AIDS patients diagnosed with pathologically or microbiologically confirmed PC from 1990-2020. Among 130 PC patients, 24 (18.5%) exhibited immunosuppression, and 44 (33.8%) had underlying diseases. In radiology, 118 (90.8%) presented with subpleural lesions, and 68 (53.1%) presented with nodules with diameters ranging from 1-5 cm. Seventy-five patients (57.7%) underwent surgery alone. PC clinical features at different time periods showed that hospitalization days decreased (P=0.009), and patients with symptoms decreased over time. Patients exhibiting isolated lesions decreased (P=0.022), and patients exhibiting subpleural lesions increased (P=0.020). Patients with lesions presenting 3-10 mm nodules increased (P=0.028). In conclusion, more and more patients have been diagnosed of PC in the last 30 years. The timing of PC diagnosis has shifted to early in disease progression. Pulmonary lesions caused by cryptococcosis are easily misdiagnosed and may lead to unnecessary surgical treatment. Further research is needed to identify lung lesions caused by cryptococcosis.