ABSTRACT
Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) are life-threatening multidrug-resistant bacteria. In this study, CR-Kp strains isolated from sewage treatment plants (STPs) (n = 12) were tested for carbapenemase genes (blaKPC, blaNDM, blaIMP, blaVIM and blaOXA-48) and had their sequence types (ST) and clonal complexes (CCs) defined. A collection of clinical CR-Kp strains recovered in local hospitals was added to phylogenetic analyses along with sewage strains in order to infer clonality among CR-Kp strains. A total of 154 CR-Kp strains were isolated from raw sewage [55.8% (86/154)], treated sewage [25.3% (39/154)] and from water body downstream from STPs [18.8% (29/154)]. No CR-Kp strain was isolated from upstream water samples. blaKPC or blaNDM were detected in 143 (92.8%) strains. The occurrence of blaKPC-or-NDM CR-Kp strains was positively associated with the number of hospitalized patients in the areas serviced by STPs. Eleven STs were detected in CR-Kp strains, most of them belonging to the clinically relevant CC11 [ST11 (n = 13-28.2%) and ST340 (n = 7-15.2%)]. CCs 11, 15, 17, 147 and 2703 are shared by clinical and sewage CR-Kp strains. In conclusion, sewage harbors clinically relevant clones of CR-Kp that resist sewage treatments, contaminating water bodies downstream from STPs.
Subject(s)
Carbapenem-Resistant Enterobacteriaceae , Klebsiella Infections , Humans , Klebsiella pneumoniae/genetics , Sewage , Phylogeny , Klebsiella Infections/drug therapy , Klebsiella Infections/epidemiology , Klebsiella Infections/microbiology , beta-Lactamases/genetics , Bacterial Proteins/genetics , Microbial Sensitivity Tests , Carbapenems/pharmacology , Carbapenems/therapeutic use , Water , Anti-Bacterial Agents/therapeutic useABSTRACT
OBJECTIVES: This study aimed to characterise insertional mutations disturbing themgrB gene in carbapenem-resistant Klebsiella pneumoniae (CRKp). METHODS: A total of 118 clinical CRKp isolates were surveyed for polymyxin resistance and insertion sequence (IS) elements disruptingmgrB. RESULTS: Of the 118 isolates, 78 (66.1%) displayed polymyxin resistance, of which 54% (42/78) hadmgrB::IS inserts. Sequencing analyses showed 13 insertion sites in mgrB. mgrB::ISSen4(IS3) was observed for the first time in CRKp. CONCLUSIONS: Ten different IS elements disruptedmgrB, with a predominance (76%) of IS5 sequences.
