phenylalanine-arginine-beta-naphthylamide and Diarrhea

Antimicrobial-resistant bacteria pose a threat to public health. Three Yersinia enterocolitica strains cultured from patients presenting with diarrhea and resistant to nalidixic acid were studied. Target gene mutations in gyrA alone were identified as part of the genetic basis for this phenotype. Efflux activity was also noted, since the presence of the efflux pump inhibitor, phenylalanine-arginine-β-naphthylamide, increased susceptibility to nalidixic acid.

Topics: Anti-Bacterial Agents; Diarrhea; Dipeptides; DNA Gyrase; Drug Resistance, Multiple, Bacterial; Humans; Microbial Sensitivity Tests; Mutation; Nalidixic Acid; Phenotype; Polymerase Chain Reaction; RNA, Bacterial; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Virulence Factors; Yersinia enterocolitica

Enteropathogens have shown a high level of resistance against commonly used antibacterial drugs in Peru and it is necessary to explore alternative treatments. The aim of this study was to analyse the in vitro activity of rifaximin against diarrhoeagenic and commensal Escherichia coli in children less than 2 years of age.. The minimal inhibitory concentration (MIC) to rifampicin and rifaximin was determined for 210 strains in the presence and absence of phenyl-arginine-β-naphthylamide (PAβN) and the mechanisms of resistance were investigated.. The MIC levels ranged between 8 and >256 mg/litre and the predominant mechanism of resistance to rifaximin was the efflux pumps inhibited by PAβN in 95.2% of the isolates.. The present MIC values are higher than those observed in other studies. Efflux pumps inhibited by PAβN were the cause of the rifaximin resistance in the majority of cases and suggest the presence of an environmental selective pressure. Consequently, rifaximin should be used with caution in the treatment of diarrhoea in Peru.

Topics: Anti-Bacterial Agents; Diarrhea; Dipeptides; Drug Resistance, Bacterial; Escherichia coli; Female; Humans; Infant; Infant, Newborn; Male; Rifamycins; Rifaximin