Volume 17, Number 6—June 2011
Dispatch
Ciprofloxacin-Resistant Salmonella enterica Serotype Typhi, United States, 1999–2008
Table 1
MICs of antimicrobial agents tested for 9 ciprofloxacin-resistant Salmonella enterica serotype Typhi isolates detected in the National Antimicrobial Resistance Monitoring System, United States, 1999–2008
Antimicrobial class and agent* | MIC, µg/mL,* by patient no. (isolate) |
||||||||
---|---|---|---|---|---|---|---|---|---|
Patient 1 (MA-03) | Patient 2† (CA-05) | Patient 3 (CA-06) | Patient 4 (TX-06) | Patient 5 (AZ-06) | Patient 6 (NY-07) | Patient 7 (CA-07) | Patient 8 (NJ-07) | Patient 9 (LAC-07) | |
Quinolones | |||||||||
Ciprofloxacin | >4 | >4 | >4 | >4 | >4 | >4 | >4 | >4 | >4 |
Nalidixic acid |
>32 |
>32 |
>32 |
>32 |
>32 |
>32 |
>32 |
>32 |
>32 |
Aminoglycosides | |||||||||
Amikacin | <0.5 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Gentamicin | <0.25 | <0.25 | <0.25 | <0.25 | <0.25 | <0.25 | <0.25 | <0.25 | <0.25 |
Kanamycin | <8 | <8 | <8 | <8 | <8 | <8 | <8 | <8 | <8 |
Streptomycin |
<32 |
<32 |
<32 |
>64 |
<32 |
<32 |
<32 |
<32 |
<32 |
β-lactam–β-lactamase inhibitor | |||||||||
Amoxicillin-clavulanic acid |
<1/0.5 |
<1/0.5 |
<1/0.5 |
8/4 |
<1/0.5 |
<1/0.5 |
<1/0.5 |
<1/0.5 |
<1/0.5 |
Cephems | |||||||||
Cefoxitin | 4 | 4 | 4 | 4 | 2 | 4 | 4 | 4 | 4 |
Ceftiofur | 0.5 | 0.5 | 0.5 | 0.5 | 0.25 | 0.5 | 0.5 | 0.5 | 0.5 |
Ceftriaxone |
<0.25 |
<0.25 |
<0.25 |
<0.25 |
<0.25 |
<0.25 |
<0.25 |
<0.25 |
<0.25 |
Folate pathway inhibitors | |||||||||
Sulfonamide‡ | >512 | >256 | <16 | >256 | >256 | <16 | >256 | <16 | <16 |
Trimethoprim-
sulfamethoxazole |
>4/76 |
>4/76 |
<0.12/ 2.38 |
>4/76 |
>4/76 |
<0.12/ 2.38 |
>4/76 |
<0.12/ 2.38 |
<0.12/ 2.38 |
Penicillins | |||||||||
Ampicillin |
2 |
<1 |
<1 |
>32 |
<1 |
<1 |
<1 |
<1 |
<1 |
Phenicols | |||||||||
Chloramphenicol |
4 |
4 |
4 |
>32 |
4 |
4 |
4 |
4 |
4 |
Tetracyclines | |||||||||
Tetracycline | >32 | >32 | <4 | <4 | >32 | <4 | >32 | <4 | <4 |
*Classes of antimicrobial agents defined by the Clinical and Laboratory Standards Institute (CLSI) were used to categorize agents (7,13). MICs were interpreted by using CLSI criteria when available (7,13): ciprofloxacin (resistance breakpoint, >4 µg/mL); nalidixic acid (>32); amikacin (>64); gentamicin (>16); kanamycin (>64); amoxicillin-clavulanic acid (>32/16); cefoxitin (>32); ceftiofur (>8); ceftriaxone (>4); sulfamethoxazole/sulfisoxazole (>512); trimethoprim-sulfamethoxazole (>4/76); ampicillin (>32); chloramphenicol (>32); and tetracycline (>16). For streptomycin, resistance was defined as MIC >64 µg/mL (7). If growth was not inhibited by the highest concentration of the agent in the panel, the MIC was reported as above the highest concentration.
†Isolate was cultured from a blood specimen. Another isolate was cultured from fecal samples, which had MIC <0.5 µg/mL for amikacin and same MICs for other agents tested.
‡Sulfamethoxazole was used during 1999–2003 and sulfisoxazole since 2004 to represent sulfonamides.
References
- Mermin JH, Townes JM, Gerber M, Dolan N, Mintz ED, Tauxe RV. Typhoid fever in the United States, 1985–1994: changing risks of international travel and increasing antimicrobial resistance. Arch Intern Med. 1998;158:633–8. DOIPubMedGoogle Scholar
- Connor BA, Schwartz E. Typhoid and paratyphoid fever in travelers. Lancet Infect Dis. 2005;5:623–8. DOIPubMedGoogle Scholar
- Centers for Disease Control and Prevention. Summary of notifiable diseases—United States, 2006. MMWR. 2008;55:32,77.
- Ackers ML, Puhr ND, Tauxe RV, Mintz ED. Laboratory-based surveillance of Salmonella serotype Typhi infections in the United States: antimicrobial resistance on the rise. JAMA. 2000;283:2668–73. DOIPubMedGoogle Scholar
- Lynch MF, Blanton EM, Bulens S, Polyak C, Vojdani J, Stevenson J, Typhoid fever in the United States, 1999–2006: trends in quinolone-resistant cases among international travelers. JAMA. 2009;302:859–65. DOIPubMedGoogle Scholar
- Crump JA, Kretsinger K, Gay K, Hoekstra RM, Vugia DJ, Hurd S, Clinical response and outcome of infection with Salmonella enterica serotype Typhi with decreased susceptibility to fluoroquinolones: a United States FoodNet multicenter retrospective cohort study. Antimicrob Agents Chemother. 2008;52:1278–84. DOIPubMedGoogle Scholar
- Centers for Disease Control and Prevention. National Antimicrobial Resistance Monitoring System for Enteric Bacteria (NARMS): human isolates final report, 2008. Atlanta: US Department of Health and Human Services; 2010.
- Cooke FJ, Wain J. The emergence of antibiotic resistance in typhoid fever. Travel Med Infect Dis. 2004;2:67–74. DOIPubMedGoogle Scholar
- Parry CM, Ho VA, Phuong le T, Bay PV, Lanh MN, Tung le T, Randomized controlled comparison of ofloxacin, azithromycin, and an ofloxacin-azithromycin combination for treatment of multidrug-resistant and nalidixic acid-resistant typhoid fever. Antimicrob Agents Chemother. 2007;51:819–25. DOIPubMedGoogle Scholar
- Hopkins KL, Davies RH, Threlfall EJ. Mechanisms of quinolone resistance in Escherichia coli and Salmonella: recent developments. Int J Antimicrob Agents. 2005;25:358–73. DOIPubMedGoogle Scholar
- Gaind R, Paglietti B, Murgia M, Dawar R, Uzzau S, Cappuccinelli P, Molecular characterization of ciprofloxacin-resistant Salmonella enterica serovar Typhi and Paratyphi A causing enteric fever in India. J Antimicrob Chemother. 2006;58:1139–44. DOIPubMedGoogle Scholar
- Turner AK, Nair S, Wain J. The acquisition of full fluoroquinolone resistance in Salmonella Typhi by accumulation of point mutations in the topoisomerase targets. J Antimicrob Chemother. 2006;58:733–40. DOIPubMedGoogle Scholar
- Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing: twentieth informational supplement. Wayne (PA): The Institute; 2010.
- Ribot EM, Fair MA, Gautom R, Cameron DN, Hunter SB, Swaminathan B, Standardization of pulsed-field gel electrophoresis protocols for the subtyping of Escherichia coli O157:H7, Salmonella, and Shigella for PulseNet. Foodborne Pathog Dis. 2006;3:59–67. DOIPubMedGoogle Scholar
- Crump JA, Mintz ED. Global trends in typhoid and paratyphoid fever. Clin Infect Dis. 2010;50:241–6. DOIPubMedGoogle Scholar