Resistance Mechanisms and Trends in Human Isolates
Resistance Mechanisms and Trends in Human Isolates
The incidence of human Campylobacter jejuni and C. coli infections has increased markedly in many parts of the world in the last decade as has the number of quinolone-resistant and, to a lesser extent, macrolide-resistant Campylobacter strains causing infections. We review macrolide and quinolone resistance in Campylobacter and track resistance trends in human clinical isolates in relation to use of these agents in food animals. Susceptibility data suggest that erythromycin and other macrolides should remain the drugs of choice in most regions, with systematic surveillance and control measures maintained, but fluoroquinolones may now be of limited use in the empiric treatment of Campylobacter infections in many regions.
Campylobacter jejuni subsp. jejuni (C. jejuni) and C. coli have been recognized since the late 1970s as important agents of gastrointestinal infections throughout the world; in the United States, these infections affect approximately 1% of the population each year. Contaminated food is the usual source of human infections; therefore, the presence of fluoroquinolone- and macrolide-resistant strains in the food chain has raised concerns that the treatment of human infections will be compromised. Most cases of Campylobacter enteritis do not require antimicrobial treatment, being brief, clinically mild, and self-limiting. However, a substantial proportion of these infections require treatment. These include severe and prolonged cases of enteritis, septicemia, and other extraintestinal infections. Erythromycin has been the most commonly used agent for treating Campylobacter enteritis.
In the 1980s, the introduction of fluoroquinolones, which are effective against most major pathogens causing bacterial enteritis, offered a new approach to antibiotic intervention. Fluoroquinolones initially had good in vitro activity for thermophilic Campylobacter species, as well as for members of the family of Enterobacteriaceae.
Early clinical trials of both community-acquired acute diarrhea and traveler's diarrhea caused by Campylobacter demonstrated that patients treated with a fluoroquinolone had good clinical response. It soon became apparent, however, that resistance in Campylobacter spp. could arise in vivo, sometimes after only one or two administrations of fluoroquinolones. Moreover, Endtz and colleagues reported as early as 1991 that the emergence of quinolone-resistant C. jejuni and C. coli isolated from humans in the Netherlands coincided with the introduction of fluoroquinolones in veterinary medicine.
Fluoroquinolone resistance in Campylobacter from food animals is now recognized as an emerging public health problem. Smith et al. from Minnesota found that patients infected with resistant C. jejuni had longer duration of diarrhea than patients with fluoroquinolone-sensitive isolates. As Campylobacter infections can be serious in immunocompromised patients, the identified treatment failure raises the concern that fluoroquinolone-resistant strains may increase Campylobacter-associated deaths in this group of patients.
The incidence of human Campylobacter jejuni and C. coli infections has increased markedly in many parts of the world in the last decade as has the number of quinolone-resistant and, to a lesser extent, macrolide-resistant Campylobacter strains causing infections. We review macrolide and quinolone resistance in Campylobacter and track resistance trends in human clinical isolates in relation to use of these agents in food animals. Susceptibility data suggest that erythromycin and other macrolides should remain the drugs of choice in most regions, with systematic surveillance and control measures maintained, but fluoroquinolones may now be of limited use in the empiric treatment of Campylobacter infections in many regions.
Campylobacter jejuni subsp. jejuni (C. jejuni) and C. coli have been recognized since the late 1970s as important agents of gastrointestinal infections throughout the world; in the United States, these infections affect approximately 1% of the population each year. Contaminated food is the usual source of human infections; therefore, the presence of fluoroquinolone- and macrolide-resistant strains in the food chain has raised concerns that the treatment of human infections will be compromised. Most cases of Campylobacter enteritis do not require antimicrobial treatment, being brief, clinically mild, and self-limiting. However, a substantial proportion of these infections require treatment. These include severe and prolonged cases of enteritis, septicemia, and other extraintestinal infections. Erythromycin has been the most commonly used agent for treating Campylobacter enteritis.
In the 1980s, the introduction of fluoroquinolones, which are effective against most major pathogens causing bacterial enteritis, offered a new approach to antibiotic intervention. Fluoroquinolones initially had good in vitro activity for thermophilic Campylobacter species, as well as for members of the family of Enterobacteriaceae.
Early clinical trials of both community-acquired acute diarrhea and traveler's diarrhea caused by Campylobacter demonstrated that patients treated with a fluoroquinolone had good clinical response. It soon became apparent, however, that resistance in Campylobacter spp. could arise in vivo, sometimes after only one or two administrations of fluoroquinolones. Moreover, Endtz and colleagues reported as early as 1991 that the emergence of quinolone-resistant C. jejuni and C. coli isolated from humans in the Netherlands coincided with the introduction of fluoroquinolones in veterinary medicine.
Fluoroquinolone resistance in Campylobacter from food animals is now recognized as an emerging public health problem. Smith et al. from Minnesota found that patients infected with resistant C. jejuni had longer duration of diarrhea than patients with fluoroquinolone-sensitive isolates. As Campylobacter infections can be serious in immunocompromised patients, the identified treatment failure raises the concern that fluoroquinolone-resistant strains may increase Campylobacter-associated deaths in this group of patients.
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