Infect Chemother.  2008 Aug;40(4):207-211. 10.3947/ic.2008.40.4.207.

Time Kill Studies of Antibiotics against a Nalidixic Acid Resistant Salmonella enterica serotype Typhi

• Kim DM
• Yun NR
• Chung JH
• Ryu HH

• KMID: 2170235
• DOI: http://doi.org/10.3947/ic.2008.40.4.207

Abstract

BACKGROUND: We recently encountered a case of typhoid fever in a patient who visited us after travelling India. The patient received ciprofloxacin therapy, but developed typhoid pneumonia and typhoid hepatitis, and nalidixic acid resistance Salmonella Typhi (NARST) was identified. The aim of this study was to assess the in vitro efficacy of several antimicrobial combinations, which are commonly used in clinical practice.
MATERIALS AND METHODS
Time-kill studies were performed for a clinical NARST strain to evaluate synergy. Synergy was defined as a > or = 2 log10 decrease (100-fold drop) in CFU per mL at 24 hours by a drug combination compared to the most active constituent.
RESULTS
The combination regimen of cefotaxime plus ciprofloxacin significantly reduced the bacterial counts (> 3 log CFU) at 3/4 MIC and at 24 hours compared to the ciprofloxacin or cefotaxime alone and showed synergistic effect against a NARST strain.
CONCLUSION
In conclusion, our time-kill studies showed that ciprofloxacin plus cefotaxime was the best in vitro combination against a NARST. This combination may improve efficacy compared to fluoroquinolone alone in typhoid fever patient with NARST. Time kill studies with more NARST strains and clinical studies are required to test the relevance of our findings

Keyword

Typhoid fever; Salmonella Typhi; Cefotaxime; Ciprofloxacin

MeSH Terms

Anti-Bacterial Agents
Bacterial Load
Cefotaxime
Ciprofloxacin
Hepatitis
Humans
India
Nalidixic Acid
Pneumonia
Salmonella
Salmonella enterica
Salmonella typhi
Sprains and Strains
Typhoid Fever
Anti-Bacterial Agents
Cefotaxime
Ciprofloxacin
Nalidixic Acid

Figure

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  Figure 1 Chest images of the patient with typhoid fever. A) Chest PA image on admission. B) Chest PA on hospital day 4, as the patient presented with dyspnea and dry caugh.

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  Figure 2 Time-kill curves for a clinical isolate of Salmonella Typhi after incubation with cefotaxime, azithromycin or ciprofloxacin alone and the combination of cefotaxime plus ciprofloxacin, azithromycin plus cefotaxime and azithromycin plus ciprofloxacin at 3/4 MIC.

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