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Antimicrobial resistance of gram-negative bacteria isolated from foods in Mexico
Abstract:
When trimethoprim-sulfamethoxazole was given to US travelers in Mexico to prevent diarrheal illness, high-level resistance to the drug emerged [2], although in previous studies such resistance had not been observed among enteric flora following administration of trimethoprim-sulfamethoxazole as prophylaxis against urinary tract infection [3]. Since food has been shown to be an important vehicle of transmission of travelers' diarrhea, food samples were examined for the presence of drug-resistant bacteria to explain the acquisition of high-level resistance among enteric flora of individuals taking antibiotics as prophylaxis against traveler's diarrhea. Of 34 strains of ETEC isolated from US students in Guadalajara, Mexico, who had acute gastroenteritis, one was resistant to trimethoprim and one was resistant to trimethoprim-sulfamethoxazole. Eight of the ETEC strains tested demonstrated multiple drug resistance. Twenty-two of 149 isolates from food produced enterotoxin. Only one isolate, which was nontoxigenic, was resistant to trimethoprim, and no coliforms were resistant to trimethoprim-sulfamethoxazole; however, 16 isolates demonstrated multiple drug resistance. Of 235 gram-negative organisms recovered from frozen food samples grown on antibiotic-containing media and tested for enterotoxin production, no isolates were enterotoxigenic. Thirty-four isolates were resistant to trimethoprim, 15 were resistant to trimethoprim-sulfamethoxazole, and 33 demonstrated multiple resistance. Multiple drug resistance was demonstrated among gram-negative organisms isolated from patients' stools and foods in Mexico.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Antibiotic resistance emerged in US travelers in Mexico. Food samples revealed drug-resistant bacteria, indicating a potential link between antibiotic use and the spread of resistant organisms in travelers' diarrhea.
Area of Science:
- Microbiology
- Infectious Diseases
- Public Health
Background:
- Travelers' diarrhea is a common illness among international travelers.
- Antibiotic prophylaxis is sometimes used to prevent travelers' diarrhea.
Purpose of the Study:
- To investigate the emergence of high-level antibiotic resistance in travelers to Mexico.
- To identify potential sources of drug-resistant bacteria, such as food, in the environment.
Main Methods:
- Isolation and characterization of bacteria from stool samples of travelers with gastroenteritis.
- Analysis of food samples for the presence of drug-resistant bacteria and enterotoxigenic strains.
- Testing for antibiotic resistance patterns, including trimethoprim and trimethoprim-sulfamethoxazole.
Main Results:
- High-level resistance to trimethoprim-sulfamethoxazole emerged in enteric flora of US travelers in Mexico.
- Multiple drug resistance was observed in both patient isolates and food isolates.
- Enterotoxigenic ETEC strains were isolated from students with gastroenteritis, and some exhibited drug resistance.
Conclusions:
- Antibiotic use for prophylaxis against travelers' diarrhea may contribute to the emergence of drug-resistant bacteria.
- Food can be a vehicle for transmitting drug-resistant bacteria.
- Surveillance of drug resistance in travelers and food sources is crucial.