Submitted to: Proceedings of the International Conference on Emerging Infectious Diseases
Publication Type: Abstract Only
Publication Acceptance Date: 5/16/2000
Publication Date: 7/16/2000
Citation: Zaidi, M., Macias, A., Mejia, C., Vazquez, G., Gordillo, M.R., Cray, P.J., Hollinger, K., Tollefson, L. 2000. Antimicrobial susceptibility of salmonella strains in from iii and asymptomatic humans. Proceedings of the International Conference on Emerging Infectious Diseases. Board 32. P. 67-68.
Technical Abstract: Background: The establishment of surveillance programs for antimicrobial drug resistance in foodborne pathogens is a worldwide priority. Methods: A three-month pilot surveillance program was conducted in four cities: 3 in Mexico and 1 in Guatemala. Salmonella isolates were collected from intestinal and extraintestinal sites from sick humans seen at their local hospitals. In addition, fecal samples from healthy, asymptomatic children less than 7 years of age were obtained from 10 daycare centers. Susceptibility testing to 12 antibiotics was performed for all Salmonella isolates by the disk-diffusion method according to NCCLS guidelines. Results: A total of 44 (10%) Salmonella strains were isolated from 435 asymptomatic children in daycare centers. Prevalence of Salmonella shedding varied from 2 to 37%. At the hospitals, 35 Salmonella isolates were obtained from feces (21), blood (11), and wounds (3). Fourteen (18%) of the 79 isolates were Salmonella typhi. The percentage of sensitive S. typhi isolates were amikacin, 100%; ampicillin, 86%; ceftriaxone, 93%; cephalothin, 93%; chloramphenicol, 86%; ciprofloxacin, 100%; gentamicin, 93%; nalidixic acid, 93%; norfloxacin, 100%; streptomycin, 79%; tetracycline, 86%; and trimethoprim-sulphamethoxazole, 93%. Susceptibility results (percent sensitive) for the 65 non-typhi Salmonella isolates were: amikacin, 95%; ampicillin, 92%; ceftriaxone, 95%; cephalothin, 94%; chloramphenicol, 94%; ciprofloxacin, 100% gentamicin, 95%; nalidixic acid, 92%; norfloxacin, 100% streptomycin, 60%; tetracycline, 57%; and trimethoprim-sulphamethoxazole, 97%. No differences were observed for susceptibility of Salmonella strains from sick patients or daycare attendees. Multiresistance was mostly observed in strains associated with nosocomial outbreaks. Conclusions: Preliminary results from our pilot study suggest that community-acquired multiresistant Salmonella isolates in sick and healthy humans are rare. In this study, no quinolone-resistant strains were isolated and the percentage of nalidixic acid-resistant isolates was low. However, a continuous monitoring program is required to detect changes in these susceptibility patterns.