Spreading of extended-spectrum β-lactamase-producing Escherichia coli ST131 and Klebsiella pneumoniae ST11 in patients with pneumonia: a molecular epidemiological study

Background: Extended-spectrum β-lactamase (ESBL)-producingEscherichia coli (E. coli) andKlebsiella pneumoniae (K. pneumoniae) are the important pathogens causing pneumonia. This study aimed to investigate the clinical characteristics and molecular epidemiology of ESBL-producingE. coli andK. pneumoniae causing pneumonia at a large teaching hospital in China.Methods: We collected patient’s clinical data and ESBL-producingE. coli andK. pneumoniae strains causing pneumonia (from December 2015 to June 2016) at a hospital in Wuhan. The susceptibilities, multi-locus sequence typing, homologous analysis, ESBL genes by polymerase chain reaction and sequencing were determined.Results: A total of 59 ESBL-producing strains (31E. coli and 28K. pneumoniae) isolated from patients with pneumonia were analyzed. The majority of strains were isolated from patients were with hospital-acquired pneumonia (37/59, 62.7%), followed by community-acquired pneumonia (13/59, 22.0%), and ventilator-related pneumonia (9/59, 15.3%). TheE. coli ST131 (9 isolates, 29.0%) andK. pneumoniae ST11 (5 isolates, 17.9%) were the predominant sub-types. The most prevalent ESBL gene wasCTX-M-14, followed bySHV-77,CTX-M-3,SHV-11, andCTX-M-27. At least 33 (55.9%) of the ESBL-producing strains carried two or more ESBL genes. TheISEcp1 andIS26 were found upstream of all blaCTX-M (CTX-Ms) and of most blaSHV (SHVs) (57.6%), respectively. Moreover, three ESBL-producingK. pneumoniae ST11 strains which were resistant to carbapenems carried theblaNDM-1 andblaKPC-2, two of which also bearingblaOXA-48 were resistant to all antibiotics (including Tigecycline).Conclusions: Hospital-acquired pneumonia is more likely correlated with ESBL-producingE. coli andK. pneumoniae. ESBL-producingE. coli ST131 and multi-drug resistance ESBL-producing, as well as New Delhi metallo-β-lactamase-1 (NDM-1) and Klebsiella pneumoniae carbapenemases-2 (KPC-2) bearingK. pneumoniae ST11 are spreading in patients with pneumonia in hospital.