Infect Chemother.  2022 Mar;54(1):59-69. 10.3947/ic.2021.0102.

High Prevalence of bla _CTX-M in Fecal Commensal Escherichia coli from Healthy Children

• Alcedo K
• Ruiz J
• Ochoa TJ
• Riveros M

• KMID: 2527866
• DOI: http://doi.org/10.3947/ic.2021.0102

Abstract

Background
Antibiotic-resistant Escherichia coli can colonize the intestinal tract of healthy children, causing concern when antibiotic resistance is related to the presence of transferable mechanisms, such as extended-spectrum β-lactamases (ESBLs).
Materials and Methods
Fecal samples from 41 healthy children from two villages of rural Peru were cultured on ceftriaxone-disks. ESBL production was confirmed with double disk synergy. In all ESBL-produced isolates, antibiotic susceptibility to 12 antibacterial agents was established by disk diffusion, while clonal relationships were determined by repetitive extragenic palindromic-polymerase chain reaction (REP-PCR). Presence of ST131 was determined using PCR.
Results
Ceftriaxone-resistant microorganisms were recovered from 39 samples belonging to 22 out of 41 children (53.7%). Of these, 80 ceftriaxone-resistant and two eftriaxoneintermediate E. coli from inside ceftriaxone-halos were confirmed as ESBL-producers. All isolates were multidrug-resistant. In 79/80 (98.8%) ceftriaxone-resistant isolates, the presence of bla _CTX-M was detected alone (58 isolates, or together with other β-lactamase (bla _TEM , 17 isolates; bla _OXA-1-like , 3 isolates; bla _TEM + bla _OXA-1-like , 1 isolate), while in one isolate no such ESBL was identified. The two ceftriaxone-intermediate isolates recovered from the same sample, carried a bla _TEM and bla _SHV respectively. Thirty-four different clones were identified, with 4 clones being recovered from different samples from the same child. Twelve clones were disseminated among different children, including 5 clones disseminated between both villages. Two clones, accounting for 3 isolates and both recovered from the same children, belonged to E. coli ST131.
Conclusion
This study demonstrates high prevalence of ESBL-carriers among healthy children living in a rural area of Peru, stressing the need for continuous surveillance and search for public health control measures.

Keyword

Antibiotic-resistance; Commensal; Extended-spectrum β-lactamases; Escherichia coli; Healthy carriers