Last data update: Sep 23, 2024. (Total: 47723 publications since 2009)
Records 1-2 (of 2 Records) |
Query Trace: Medalla FM [original query] |
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Antimicrobial susceptibility to azithromycin among Salmonella enterica isolated in the United States
Sjolund-Karlsson M , Joyce K , Blickenstaff K , Ball T , Haro J , Medalla FM , Fedorka-Cray P , Zhao S , Crump JA , Whichard JM . Antimicrob Agents Chemother 2011 55 (9) 3985-9 Due to emerging resistance to traditional antimicrobial agents such as ampicillin, trimethoprim-sulfamethoxazole and chloramphenicol, azithromycin is increasingly used for the treatment of invasive Salmonella infections. In the present study, 696 isolates of non-Typhi Salmonella collected from humans, food animals and retail meats in the United States were investigated for antimicrobial susceptibility to azithromycin. Seventy two Salmonella enterica serotype Typhi isolated from humans were also tested. For each isolate, minimum inhibitory concentrations (MICs) to azithromycin and 15 other antimicrobial agents were determined by broth microdilution. Among the non-Typhi Salmonella isolates, azithromycin MICs among human isolates ranged from 1-32 mcg/mL whereas the MICs among the animal and retail meat isolates ranged from 2-16 mcg/mL and 4-16 mcg/mL, respectively. Among Salmonella ser. Typhi isolates the azithromycin MICs ranged from 4-16 mcg/mL. The highest MIC observed in the present study was 32 mug/mL and was detected in three isolates from humans belonging to serotypes Kentucky, Montevideo and Paratyphi A. Based on our findings, we propose an epidemiological cut-off value (ECOFF) of wild type ≤ 16 mcg/mL for azithromycin and Salmonella. The susceptibility data provided could be used in combination with clinical outcome data to determine tentative clinical breakpoints for azithromycin and Salmonella enterica. |
Antimicrobial resistance among invasive nontyphoidal Salmonella enterica in the United States, National Antimicrobial Resistance Monitoring System, 1996-2007
Crump JA , Medalla FM , Joyce KW , Krueger AL , Hoekstra RM , Whichard JM , Barzilay EJ . Antimicrob Agents Chemother 2011 55 (3) 1148-54 Nontyphoidal salmonellae (NTS) are important causes of community-acquired bloodstream infection. We describe patterns of antimicrobial resistance among invasive NTS in the United States. We compared bloodstream NTS isolates with those from stool submitted to the National Antimicrobial Resistance Monitoring System (NARMS) from 1996-2007. We described antimicrobial resistance among invasive strains by serogroup and serotype. Of the 19,302 NTS, 17,804 (92.2%) were from stool or blood. Of these, 1,050 (5.9%) were bloodstream isolates. The median age (range) of patients with and without bacteremia was 36 (0, 97) years and 20 (0, 105) years, respectively (p<0.001). Males (OR 1.21, 95% CI 1.06, 1.38) and those aged ≥65 years were at greater risk for invasive disease. Enteritidis, Typhimurium, and Heidelberg were the most common serotypes isolated from blood; Dublin, Sandiego, and Schwarzengrund were associated with the greatest risk for bloodstream isolation. Of invasive isolates 208 (19.8%) were resistant to ampicillin, 117 (11.1%) to chloramphenicol, and 26 (2.5%) to trimethoprim-sulfamethoxazole; 28 (2.7%) isolates were resistant to nalidixic acid and 26 (2.5%) to ceftriaxone. Antimicrobial resistance to traditional agents is common. However, the occurrence of nalidixic acid and ceftriaxone resistance among invasive NTS is cause for clinical and public health vigilance. |
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