[Antimicrobial susceptibility and resistance genes among Salmonella enterica Serovar Weltevreden isolates from humans, farm animals, and the environment in Okinawa Prefecture between 1992 and 2007].

This study analyzed 86 samples of Salmonella enterica Weltevreden, collected over 15 years from both humans and various farm animals in Okinawa, Japan, in order to determine their susceptibility to certain antibiotics. Only a small percentage showed resistance, with most appearing susceptible to all tested treatments. Antibiotic-resistant samples contained resistance genes for their respective medications.

Examining the Samples

• Over a period of 15 years between 1992 and 2007, 86 total samples of a bacterium called Salmonella enterica Weltevreden were collected. This bacterium is known for causing gastrointestinal illness in both humans and animals.
• These samples came from a number of sources in the Okinawa Prefecture in Japan. A little under half (41) were derived from humans, while the rest came from various farm animals and their environments.

Testing for Antimicrobial Resistance

• The samples were then tested for their resistance to a variety of antimicrobial substances. This was done to measure the level of drug resistance among these bacteria, which is an important factor in treating potential infections.
• Only a small fraction (8.1%) of these samples proved resistant to one or more of the tested drugs.
• The rest of the samples were susceptible to all the substances, including gentamicin, sefuroxime, colistin, nalidixic acid, fosfomycin and ofloxacin.

Identifying Resistance Patterns

• Among the resistant samples, six distinct drug resistance patterns were identified, potentially due to combining various antibiotics during treatment.
• Specific samples showed resistance to streptomycin, ampicillin, kanamycin, oxytetracycline, chloramphenicol, and suffamethoxazole/trimethoprim.

Identifying Resistance Genes

• Investigation into the DNA of the resistant strains revealed that each contained specific genes that are known to provide resistance to certain drugs.
• These included two ampicillin-resistant bacteria samples that contained the blaTEM gene, four streptomycin-resistant samples with the aadA gene, two streptomycin-resistant samples with the strA gene, two tetracycline-resistant samples with the tetA gene, three tetracycline-resistant samples with the tetB gene, and two chloramphenicol-resistant samples with the catA1 gene.