The importance of Escherichia coli clonal complex 10 and ST131 among Tanzanian patients on antimicrobial resistance surveillance programs.

The objective of this study was to characterize antimicrobial resistance (AMR) of WHO priority 1 critical pathogen (extrapathogenic Escherichia coli (ExPEC), sequence types (STs), and ST131 clades from patients in Tanzania so as to guide specific antimicrobial therapies and preventive measures. A total of 143 ExPEC strains (128 from pregnant women with urinary tract infections and 15 from children with blood stream infections) were collected between March 2016 and October 2017. These were characterized into ST-fimH clones by a 7-single nucleotide polymorphism quantitative polymerase chain reaction (7-SNP qPCR) and gene sequencing, and to ST131 clades by multiplex PCR. The extended-spectrum beta-lactamases (ESBL) production was 16.1% (23/143), and was predominantly due to the blaCTX-M-15 (91.3%, n=21). ESBL production was significantly more among strains from children (53.3%) than pregnant women (11.7%) (OR (95%CI): 8.61 (2.73-27.15); p-value <0.001)). Approximately 61.5% (n=88) ExPEC were typed into their respective STs/CCs (87 by the 7-SNP qPCR and by an additional of one or two genes sequencing). The commonest STs/CCs among typeable strains were CC10 (28.4%, n=25), ST131 (18.2%, n=16), and ST38 (10.2%, n=9). The ST131 clades (C1 (4, 25.0%) and C2 (6, 37.5%)) were predominantly associated with fluoroquinolone resistance and ESBL production, respectively. Approximately 60.8% of ExPEC strains and all dominant clones were typed by the 7-SNP qPCR by additional sequencing. The multiplex clade PCR allowed linkage of the global clone ST131 with AMR phenotypes. These feasible and user-friendly molecular tools can be routinely used for surveillance programs in resource-limited settings.