Resistance phenotype and clinical molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae among pediatric patients in Shanghai

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) has caused wide global disseminations and serious clinical outcomes in pediatric patients, and the purpose of this study was to analyze drug resistance, molecular epidemiology, and clinical characteristics of CRKP from children in Shanghai, China. Methods: A retrospective study was conducted from January 2016 to December 2017, and a total of 170 CRKP isolates were collected. Antimicrobial susceptibility was determined by the broth microdilution method. MAST D73C and polymerase chain reaction were used for the analysis of carbapenemase types. Multilocus sequence typing of K. pneumoniae was performed for genetic relationship. Clinical data were also reviewed. Results: Of the 170 CRKP isolates, bla(OXA-232 )was mainly detected with a proportion of 42.35%, followed by bla(NDM-1) (20.59%), bla(KPC-2) (17.65%), bla(NDM-5) (16.47%), and bla(IMP-4) (1.18%). The predominant gene was bla(OXA-232) in 2016 (54.46%; 55/101) and bla(NDM-1 )in 2017 (31.88%; 22/69). All these 170 CRKP isolates showed high resistance to cephalosporins and carbapenems (>95%), except for tigecycline and colistin. Sixteen distinct sequence types were observed with ST15 being mostly identified (41.76%). Most CRKP harboring OXA-232 type carbapenemase belonged to ST15, while NDM-1 type belonged to ST37 and KPC-2 type belonged to ST11. Furthermore, other beta-lactamase genes including bla(TEM), bla(CTX-M), and DHA-1 were also found in this study. Clinical data reviewed that more than half of the patients produced clinical infections (112/170), mainly lower respiratory tract (58/112) and bloodstream (21/112) infections. A majority of these children had received therapy of antibiotics before CRKP isolation, especially for carbapenems (76/170) and beta-lactam/beta-lactamase inhibitor combinations (91/170). Conclusions: Our data revealed the increasing incidence of OXA-232-producing K. pneumoniae from pediatric patients in Shanghai, and infection control measures should be conducted to limit the spread of CRKP strains.