Transcriptome analysis of beta-lactamase genes in diarrheagenic Escherichia coli

Abstract

Beta (β)-lactamases are the most important agents that confer drug resistance among gram-negative bacteria. Continuous mutations in β-lactamases make them remarkably diverse. We carried out the transcriptome analysis of 10 β-lactamase genes of Extended-Spectrum β-lactamases (ESBL), Metallo β-lactamases (MBL), and AmpC β-lactamases (ABL) in drug-resistant and sensitive diarrheagenic E. coli (DEC) isolates obtained from children up to 5 years of age. Out of the 10 β-lactamase genes, four belonged to ESBL ( TEM , SHV , CTX, and OXA ); three to MBL ( NDM -1, IMP , and VIM ); and three to ABL ( ACT , DHA and CMY ) class of genes. The different categories of DEC were estimated for β-lactamases production using a set of conventional phenotypic tests, followed by detection of their messenger RNA (mRNA) expression. The study revealed a direct correlation between mRNA expression of these genes and the presence of antibiotic resistance; also corroborated by mutation analysis of the AmpC promoter region. All the 10 β-lactamase genes showed a significant increase in their expression levels in resistant isolates, compared to those of the sensitive isolates, indicating their possible role in the disease pathogenesis. Increase in mRNA expression of β-lactamase genes, and thereby virulence, may be due to multifactorial parameters causing phenotypic as well as genotypic changes. Our study highlights the necessity of instantaneous detection of β-lactamase gene expression to curb the overwhelming threat posed by emergence of drug resistance amongst the commensal E. coli strains in children from developing countries for larger public health interest.

AmpC β-Lactamase Variable Expression in Common Multidrug-Resistant Nosocomial Bacterial Pathogens from a Tertiary Hospital in Cairo, Egypt

“…Moreover, a retrospective study that investigated the development of resistance to antimicrobials in P. aeruginosa showed that imipenem or ciprofloxacin therapy is a key factor of producing resistant strains of P. aeruginosa [ 45 ]. Similarly, it was indicated that the ABR of E. faecium to β -lactams is correlated with possessing the blaZ-blaI-blaR1 operon [ 46 ].…”

Genome-wide Analysis of Four Enterobacter cloacae complex type strains: Insights into Virulence and Niche Adaptation

“…www.nature.com/scientificreports www.nature.com/scientificreports/ Several genes responsible for antibiotic resistance were also retrieved by computational analysis (Table S2) in Ecc, including β-lactamase-encoding, ABC transporter and efflux system genes (Table S2). In the past two decades, bacteria producing extended-spectrum β-lactamase (ESBL) have been identified mostly from humans and animals samples 11 . ESBLs confer resistance to extended-spe ctrum cephalosporins (ESCs, e.g., ceftriaxone, cefpodoxime, ceftiofur, ceftazidime) and monobactams and often express resistance to non-β-lactam antimicrobials, leaving limited therapeutic options.…”

“…Moreover, recent studies have shown that in addition to direct killing effects, exposure to antibiotics at subinhibitory concentrations could cause an increase or reduction in the virulence of human and animal bacterial pathogens. The prediction of resistance genes in this pool revealed that Ecc strains are potentially threatening 11 .…”

Reversal of heavy metal-induced antibiotic resistance by dandelion root extracts and taraxasterol

“…To analyse the mRNA expression of β-lactamaseand acetyltransferase-encoding genes, total RNA was isolated from the bacteria using TriReagent (Invitrogen, Carlsbad, CA, USA) and converted to cDNA using the a High-Capacity cDNA reverse transcription kit (New England Biolabs, Pickering, Canada). Relative transcript levels of the β-lactamase encoding gene TEM-1 and acetyltransferase encoding gene AAC(3)IV were assayed with an iCycler iQ 5 apparatus (Bio-Rad, Mississauga, Canada) associated with iCycler optical system software (version 3.1) using SYBR Green PCR Master Mix [22][23][24][25]. The mRNA quantification was calculated by using the formula 2 −ΔΔCT , where ΔCT is the difference between the threshold cycle of a given target cDNA and an endogenous reference of 16S rRNA gene.…”

“…In contrast, the addition of either dandelion root extract or TS brought the activities of these two enzymes to the basal level when compared with the group of cadmium and antibiotic together. To observe whether the altered activities of these enzymes are attributed to their transcriptional changes, we further measured the mRNA expressions of the β-lactamase gene TEM-1 and the acetyltransferase-encoding gene AAC(3) IV [22][23][24][25]. As shown in Fig.…”