Increase in Nalidixic Acid Resistance among Non-Typhi Salmonella enterica Isolates in the United States from 1996 to 2003

Abstract

Fluoroquinolones commonly are used to treat adult Salmonella infections. Fluoroquinolone treatment has failed for persons infected with nalidixic acid-resistant Salmonella. From 1996 to 2003, state public health laboratories forwarded 12,252 non-Typhi Salmonella enterica isolates to the Centers for Disease Control and Prevention for antimicrobial susceptibility testing; 203 (1.6%) of the isolates were nalidixic acid resistant, and 14 (7%) of those were ciprofloxacin resistant. Resistance to nalidixic acid significantly increased from 0.4% in 1996 to 2.3% in 2003. All ciprofloxacin-resistant isolates had at least one point mutation in the quinolone resistance determining region (QRDR) of gyrA and did not harbor qnr or have point mutations in the QRDR of gyrB, parC, or parE. Continued surveillance of antimicrobial resistance among non-Typhi S. enterica isolates is needed to mitigate the increasing prevalence of nalidixic acid resistance.

Increased resistance to Nalidixic acid and Ciprofloxacin in Salmonella isolates from the Sub Himalayan region

“…Variable isolation rate of NAR strains from 2.3% to 96% has been documented. 3,17 Similar findings have been reported from neighbouring regions as Pakistan, Bangladesh, Nepal and other countries. 9,[18][19][20] In the present study high isolation rate of NARST 97.5% in comparison to earlier studies was seen.…”

Prevalence and antibiotic-resistance of Salmonella isolated from food in Morocco

“…However, the four isolates showed susceptibility to ciprofloxacin. Fluoroquinolones are the current drugs of choice for the treatment of invasive Salmonella infections in adults, and resistance to NAL may invalidate fluoroquinolone therapy [24].…”

Brote de Salmonella Enteritidis resistente a ácido nalidíxico en Popayán, Cauca, 2011

“…Sin embargo, desde 1990, los reportes de resistencia antimicrobiana a la ampicilina y al ácido nalidíxico en Salmonella Enteritidis en infecciones en humanos, se ha incrementado en varios países, manteniéndose la resistencia a otros antimicrobianos de forma esporádica (12)(13)(14)(15). Además, la resistencia al ácido nalidíxico se considera un marcador de disminución de la sensibilidad a la ciprofloxacina, la cual se ha reportado en aislamientos de Salmonella (16).…”

“…También se ha demostrado que la reducción de la sensibilidad a la ciprofloxacina es cada vez más común en muchas partes del mundo, con rangos de CIM para ciprofloxacina entre 0,125 y 1 µg/ml en aislamientos de Salmonella enterica (13,30), lo que se considera sensible según los puntos de corte del CLSI para ciprofloxacina en aislamientos de Salmonella de origen intestinal (22). Por lo tanto, la resistencia a la ciprofloxacina con CIM de 4 mg/ml o más no es frecuente en dichos aislamientos (14).…”