[Analysis on distribution and drug resistance of pathogen caused community-onset bloodstream infection].

OBJECTIVE

To investigate the distribution and drug resistance of pathogen caused community-onset bloodstream infection (COBSI) in patients of affiliated hospital of university, and to provide evidence for the clinical therapy.

METHODS

The clinical data of patients with COBSI in emergency department admitted to Huashan North Hospital Affiliated to Fudan University from January 2014 to December 2017 were collected, and the distribution and drug resistance of pathogen were retrospectively analyzed. The patients were divided into community-acquired bloodstream infection (CABSI) group and health care-associated bloodstream infection (HCABSI) group according to clinical diagnosis. The source of patients, past health status, blood culture isolation of pathogens, drug sensitivity test results were recorded, and the trend of drug resistance of main pathogens to common antibiotics from 2014 to 2017 were analyzed.

RESULTS

A total of 258 pathogens were isolated from patients, including 186 Gram-negative pathogens (G pathogens, 72.09%) and 72 Gram-positive pathogens (G pathogens, 27.91%), while the fungal strain was not isolated. The two most frequently isolated G pathogens causing CABSI were Escherichia coli (80 isolates, 65.57%) and Klebsiella pneumonia (24 isolates, 19.67%), including extended-spectrum beta-lactamases (ESBLs)-producing Escherichia coli (37 isolates) and Klebsiella pneumonia (3 isolates), the average detection rates were 46.25% and 12.50% respectively. The two most frequently isolated G pathogens were Streptococcus (32 isolates, 57.14%) and Staphylococcus (15 isolates, 26.79%), but methicillin-resistant Staphylococcus aureus (MRSA) had not been isolated. The two most frequently isolated G pathogens causing HCABSI were Escherichia coli (45 isolates, 70.32%) and Klebsiella pneumonia (7 isolates, 10.94%), including ESBLs-producing Escherichia coli (20 isolates) and Klebsiella pneumonia (1 isolate), the average detection rate was 44.44% and 14.29%, respectively. The most frequently isolated G pathogens were Staphylococcus (10 isolates, 62.50%), Streptococcus (3 isolates, 18.75%) and Enterococcus faecium (3 isolates, 18.75%), including MRSA (3 isolates). ESBLs-positive Escherichia coli and Klebsiella pneumoniae were almost completely resistant to cefazolin and highly resistant to ampicillin, ampicillin sodium and sulbactam sodium, ceftriaxone and furadantin, with the drug resistance rates of higher than 50%, and the drug resistance rate was significantly higher than that of corresponding ESBLs-producing negative pathogens. Escherichia coli were completely sensitive to piperacillin tazobactam, imipenem, and ertapenem, but Klebsiella pneumoniae had some resistance to piperacillin tazobactam and imipenem. Methicillin-resistant coagulase-negative Staphylococci (MRCNS) were highly resistant to common antibiotics, while Streptococcus strains and MRSA had low resistance rates, and all pathogens were completely sensitive to linezolid and vancomycin. The average annual resistance rate of Escherichia coli to common antibiotics in CABSI group was increased, but the difference was significant only for ciprofloxacin (from 2014 to 2017, they were 37.5%, 28.6%, 52.6%, 65.2%, respectively, Z = 5.076, P = 0.024). The average annual resistance rate of Klebsiella pneumonia to cefazolin and ciprofloxacin in CABSI group and that of Escherichia coli to ceftriaxone in HCABSI group showed an increasing trend without significant differences.

CONCLUSIONS

Escherichia coli and Klebsiella pneumoniae were the main pathogens of emergency COBSI, ESBLs-producing Escherichia coli were more common, and the average annual drug resistance rate to common clinical antibiotics was increasing. The drug resistance of ESBLs-producing Escherichia coli and Klebsiella pneumoniae was more serious than that of ESBLs-producing negative pathogens, so antibiotics should be used rationally.