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Antimicrobial Agents and Chemotherapy, December 2005, p. 5189, Vol. 49, No. 12
0066-4804/05/$08.00+0 doi:10.1128/AAC.49.12.5189.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
Levofloxacin and Moxifloxacin Increase Human Gut Colonization by Candida Species

LETTER
The human gut is the natural habitat of many bacterial species.
The normal bacterial microflora of the gut, especially the zillions
of anaerobes, prevent colonization by pathogenic bacteria (
2).
The use of antimicrobials is the main reason for the loss of
the normal flora and its replacement by potentially pathogenic
microorganisms, such as gram-negative aerobic bacilli and
Candida species. Colonization by
Candida species is an independent risk
factor for invasive disease (
7). Quinolones are currently among
the main classes of antibiotics used worldwide. Among them,
the newer fluoroquinolones levofloxacin and moxifloxacin have
enhanced activity against respiratory and anaerobic pathogens
(
1,
3). No studies have examined the role of these two antimicrobial
agents on the gut colonization of humans by
Candida species.
Therefore, we evaluated the effect of levofloxacin and moxifloxacin
on the human gastrointestinal tract colonization by
Candida species in 30 patients who received levofloxacin or moxifloxacin
for 8 to 10 days as monotherapy for the treatment of a variety
of infections. Fifteen patients received levofloxacin at 500
mg/day, and 15 patients received moxifloxacin at 400 mg/day.
Quantitative stool cultures for
Candida species were performed
immediately before, at the end, and 1 week after the end of
antibiotic treatment. Stool specimens were collected in sterile
plastic containers. Each gram of stool was mixed with 9 ml of
sterile normal saline and emulsified in a vortex mixer. Subsequently,
10-fold serial dilutions with saline were performed, and 0.1
ml of each dilution was inoculated onto Sabouraud dextrose agar.
Candida colonies were counted after incubation at 37°C for
48 h. Identification of the isolates was done with the use of
the API 20C AUX system (BioMérieux, Marcy l' Etoile,
France). Twelve patients in the levofloxacin group and 14 in
the moxifloxacin group had baseline cultures positive for
Candida species. Both antibiotics increased intestinal colonization
by the yeast. Levofloxacin caused a greater increase (1.8 log
10 CFU/g of stool) compared to moxifloxacin (1.2 log
10 CFU/g of
stool) (Table
1). These increases were statistically significant
(
P < 0.001) compared to pretreatment values. A persistent
and statistically significant increase in the gastrointestinal
Candida concentration was also seen by quantitative stool cultures
1 week after the end of therapy in both groups (
P < 0.005
for levofloxacin and
P < 0.008 for moxifloxacin). In the
past, we and others have shown that other quinolones, such as
ciprofloxacin, norfloxacin, and ofloxacin, caused smaller increases
in the human gut colonization by
Candida species (
4-
6). Our
results can be explained by the increased in vitro potency of
levofloxacin and moxifloxacin against anaerobes (
3), although
this activity in vivo has been questioned (
1). It is of interest
that 1 week after discontinuation of antibiotic therapy, the
median concentration of
Candida organisms in the stools, although
decreased, did not return to baseline levels, as previously
seen with ciprofloxacin, norfloxacin, and ofloxacin. In conclusion,
we showed that levofloxacin and moxifloxacin can significantly
increase the concentration of
Candida species in the human gut.
Hence, these agents should be used with caution in patients
at risk for systemic fungal infections.
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TABLE 1. Median concentration of Candida species before treatment, on the last day of treatment, and 1 week after the end of treatment
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REFERENCES
1 - Edlund, C., and C. E. Nord. 1999. Effect of quinolones on intestinal ecology. Drugs 58(Suppl. 2):65-70.
2 - Guarner, F., and J. R. Malagelada. 2003. Gut flora in health and disease. Lancet 361:512-519.[CrossRef][Medline]
3 - Hooper, D. C.2005. Quinolones, p. 451-473. In G. L. Mandell, R. G. Douglas, and J. E. Bennet (ed.), Principles and practice of infectious diseases, 6th ed. Churchill Livingstone, New York, N.Y.
4 - Mavromanolakis, E., S. Maraki, A. Cranidis, Y. Tselentis, D. P. Kontoyiannis, and G. Samonis. 2001. The impact of norfloxacin, ciprofloxacin and ofloxacin on human gut colonization by Candida albicans. Scand. J. Infect. Dis. 33:477-478.[CrossRef][Medline]
5 - Samonis, G., A. Gikas, P. Toloudis, S. Maraki, G. Vrentzos, Y. Tselentis, N. Tsaparas, and G. P. Bodey. 1994. Prospective evaluation of the impact of broad-spectrum antibiotics on the yeast flora of the human gut. Eur. J. Clin. Microbiol. Infect. Dis. 13:665-667.[CrossRef][Medline]
6 - Scully, B. E., K. Jules, N. X. Chin, and H. C. Neu. 1987. Effect of ciprofloxacin on fecal flora of patients with cystic fibrosis and other patients treated with oral ciprofloxacin. Am. J. Med. 82:336-338.[Medline]
7 - Wey, S. B., M. Mori, M. A. Pfaller, R. F. Woolson, and R. P. Wenzel. 1989. Risk factors for hospital-acquired candidemia: a matched case-control study. Arch. Intern. Med. 149:2349-2353.[Abstract/Free Full Text]
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George Samonis*
Diamantis P. Kofteridis
Sofia Maraki
Dimitrios Alegakis
Elpis Mantadakis
John A. Papadakis
Achilleas H. Gikas
The University of Crete Division of Medicine Heraklion, Crete, Greece
Matthew Falagas
Alfa Institute of Biomedical Sciences Athens, Greece
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* Phone: 30-2810-392426, Fax: 30-2810-392802, E-mail: georgsec{at}med.uoc.gr |
Antimicrobial Agents and Chemotherapy, December 2005, p. 5189, Vol. 49, No. 12
0066-4804/05/$08.00+0 doi:10.1128/AAC.49.12.5189.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.