Antimicrobial Resistance and Transconjugants Characteristics of sul3 Positive Escherichia coli Isolated from Animals in Nanning, Guangxi Province

Determining the prevalence and genetic diversity of plasmid-mediated sulfonamide resistance in Escherichia coli from commercial broiler samples

Sulfonamides are commonly used antibacterials in commercial poultry, contributing toward the development of multidrug-resistant (MDR) phenotypes among Escherichia coli and that has emerged as global concern. The current study aimed to assess the sulfonamide resistance among isolated E. coli strains among commercial broilers. The bacterial strains were identified from fecal samples (n = 100) using selective media, followed by initial identification based on biochemical profiles. The susceptibility was determined by measuring the minimum inhibitory concentration (MIC) against sulfamethoxazole. The study also evaluated mobile genetic elements (MGEs), the mediators of antibiotic resistance, by amplification of plasmid DNA using specific primer PCR. Additionally, the isolates were subjected to multilocus sequence typing (MLST) analysis to investigate the genetic diversity among E. coli carrying sulfonamide resistance genes. The results revealed that 58% (58/100) E. coli strains were resistant to sulfonamides, with 36.20% (21/58) of the strains exhibiting an MIC breakpoint ≥512 µg/mL. PCR analysis showed that 42.85% (9/21) of the strains harbored the sul-1 gene, while 38.09% (8/21) carried the sul-2 gene, and 19.04% (4/21) had both genes. No isolate showed the presence of the sul-3 gene. Furthermore, class 1 and class 2 integrons were identified among 80.95% (17/21) and 19.04% (4/21) of the strains, respectively. MLST analysis confirmed that the strains belonged to sequence types (STs) including ST1638, ST155, ST48, ST350, ST23, ST156, and ST746. These findings underscore the diversity among E. coli strains in commercial poultry, which poses a significant risk.

Antibiotic Resistance in Bacteria—A Review

Background: A global problem of multi-drug resistance (MDR) among bacteria is the cause of hundreds of thousands of deaths every year. In response to the significant increase of MDR bacteria, legislative measures have widely been taken to limit or eliminate the use of antibiotics, including in the form of feed additives for livestock, but also in metaphylaxis and its treatment, which was the subject of EU Regulation in 2019/6. Numerous studies have documented that bacteria use both phenotypis and gentic strategies enabling a natural defence against antibiotics and the induction of mechanisms in increasing resistance to the used antibacterial chemicals. The mechanisms presented in this review developed by the bacteria have a significant impact on reducing the ability to combat bacterial infections in humans and animals. Moreover, the high prevalence of multi-resistant strains in the environment and the ease of transmission of drug-resistance genes between the different bacterial species including commensal flora and pathogenic like foodborne pathogens (E. coli, Campylobacter spp., Enterococcus spp., Salmonella spp., Listeria spp., Staphylococcus spp.) favor the rapid spread of multi-resistance among bacteria in humans and animals. Given the global threat posed by the widespread phenomenon of multi-drug resistance among bacteria which are dangerous for humans and animals, the subject of this study is the presentation of the mechanisms of resistance in most frequent bacteria called as “foodborne pathoges” isolated from human and animals. In order to present the significance of the global problem related to multi-drug resistance among selected pathogens, especially those danger to humans, the publication also presents statistical data on the percentage range of occurrence of drug resistance among selected bacteria in various regions of the world. In addition to the phenotypic characteristics of pathogen resistance, this review also presents detailed information on the detection of drug resistance genes for specific groups of antibiotics. It should be emphasized that the manuscript also presents the results of own research i.e., Campylobacter spp., E. coli or Enetrococcus spp. This subject and the presentation of data on the risks of drug resistance among bacteria will contribute to initiating research in implementing the prevention of drug resistance and the development of alternatives for antimicrobials methods of controlling bacteria.