Abstract
Recently, the emergence and rapid dissemination of extended-spectrum beta-lactamase (ESBL)-producing bacteria, particularly of the family Enterobacteriaceae, has posed serious healthcare challenges. Here, we determined the antimicrobial susceptibility and genetic characteristics of 164 Escherichia coli strains isolated from infected patients in two hospitals in Ghana. In total, 102 cefotaxime-resistant isolates (62.2%) were identified as ESBL-producers. Multilocus sequence typing of the ESBL-producers identified 20 different sequence types (STs) with ST131 (n = 25, 24.5%) as the dominant group. Other detected STs included ST410 (n = 21, 20.6%) and ST617 (n = 19, 18.6%). All identified ESBL-producers harbored blaCTX-M-14, blaCTX-M-15, or blaCTX-M-27, with blaCTX-M-15 (n = 96, 94.1%) being the most predominant ESBL allele. Further analysis showed that the immediate genetic environment around blaCTX-M-15 is conserved within blaCTX-M-15 containing strains. Five of the 25 ST131 isolates were clustered with clade A, one with sub-clade C1, and 19 with the dominant sub-clade C2. The results show that fluoroquinolone-resistant, blaCTX-M-14- and blaCTX- M-15-producing ESBL E. coli ST131 strains belonging to clade A and sub-clades C1 and C2 are disseminating in Ghanaian hospitals. To the best of our knowledge, this is the first report of the ST131 phylogeny in Ghana.
Highlights
Beta-lactam antimicrobials have been used extensively in healthcare settings and animal husbandry to treat bacterial infections
Serine 83 to leucine (S83L) and aspartic acid 87 to asparagine (D87N), were observed in the GyrA regions of 19 isolates, and the single mutation serine 83 to leucine (S83L) was detected in the GyrA region of five fimH41 isolates, four of which carried blaCTX-M-14-extended-spectrum beta-lactamase (ESBL) (Supplementary data S1)
All blaCTX-M-15 isolates with double mutations were associated with elevated MICs for fluoroquinolones, and especially ciprofloxacin (> 8 μg/mL), compared to the relatively low MICs (1 μg/mL) of fluoroquinolones for the fim-H41, blaCTX-M-14 ESBL strains (Supplementary data S2) with single mutations
Summary
Beta-lactam antimicrobials have been used extensively in healthcare settings and animal husbandry to treat bacterial infections. Following its first identification in 2008, ST131 has attained global dominance, possibly primed by the sequential acquisition of certain virulence factors and antibiotic-resistant d eterminants[4,5,6]. Proliferation of this pathogenic clone was demonstrated to be driven by a single subclone, H 307,8, named clade C, which carries genes encoding the type 1 fimbriae adhesin. Clade B, known to be involved in humanto-animal transmission, is typically fluoroquinolone-susceptible and differs from clade C by 70 nucleotide substitutions; and is identified primarily by fimH223,14. Antimicrobial agents Piperacillin Cefazolin Cefotaxime Ceftazidime Cefepime Sulbactam/ampicillin Cefpodoxime Aztreonam Imipenem Meropenem Gentamicin Amikacin Minocycline Fosfomycin Sulfamethoxazole/trimethoprim Levofloxacin Cefmetazole Ciprofloxacin
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