The problem of emerging resistant microorganisms such as Methicillin-Resistant Staphylococcus aureus (MRSA) associated to livestock is closely linked to improper use of antimicrobial agents. The aim of this study is to find out the prevalence and characteristics of these strains, as well as their evolution in healthy pigs on the Island of Tenerife, Spain. Between October 2009 and December 2010, 300 pigs from 15 wean-to-finishing farms were screened. Between 1 September 2017 and 31 March 2018, a new sampling was performed collecting 125 nasal swabs from pigs belonging to the same farms and under the same conditions as the previous study. MRSA antibiotic resistant patterns were studied. Results: Prevalence of MRSA isolates was 89.6%. All isolates belonged to Sequence Type 398 (ST398), a livestock related strain. All strains studied were resistant to beta-lactamic non-carbapenemic antibiotics and sensitive to teicoplanin, linezolid, vancomycin, rifampicin, quinupristin-dalfospristin, and mupirocine. Between 2009/2010–2017/2018 a significant increase in resistance to gentamicin, tobramycin, trimethoprim-sulfomethoxazole, clindamycin, Fosfomycin, and tigecycline antibiotics was observed in isolated MRSA strains compared to the previous period. We consider a major control and surveillance program of antibiotic use in veterinary care is needed in order to reduce the presence of MRSA strains in livestock and control this significant multi-resistance increase.

Background: Antibiotic-resistant bacteria can circulate among human and animal populations through direct contact with animals, as well as via food and the environment. The purpose of this study was to examine the prevalence and characterisation of multiresistant bacteria in pig samples. Methods: 224 samples of pig livestock were taken at the slaughterhouse on the island of Tenerife. A nasal and a rectal sample were collected from each pig. The presence of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus coagulase-negative (MRCoNS), vancomycin-resistant Enterococcus (VRE), extended-spectrum ß-lactamase-producing Enterobacteriaceae (BLEE), carbapenemase-producing Enterobacteriaceae (CPE), and colistin-resistant Enterobacteriaceae was investigated. The resistance genes of the isolated bacteria were characterised by specific PCRs depending on the microorganism to be studied, and in vitro antimicrobial resistance was determined using the broth microdilution method (Vitek^®2 system bioMérieux^®, Nurtingen, Germany). Results: MRSA prevalence was 73.21% (164 isolates). MRCoNS prevalence was 9.8% (22 isolates), S. sciuri being the prevalent species. Six isolates presented a 2.7% prevalence of extended-spectrum ß-lactamase-producing Escherichia coli (BLEE) in the CTX-M-1 group. No vancomycin-resistant Enterococcus (VRE), carbapenemase-producing Enterobacteriaceae (CRE), or colistin-resistant Enterobacteriaceae were isolated. Conclusion: we found a high presence of multiresistant bacteria, suggesting the need for increased control and surveillance of this type of strains in pig livestock and a better understanding of the possible transmission routes of these microorganisms through livestock products.

C. difficile is a major cause of antibiotic-associated diarrhea and hospital-acquired infections, although increasing community-acquired cases suggest alternative transmission routes. Livestock, particularly pigs, have been proposed as potential reservoirs. This study aimed to investigate the presence of zoonotic ribotypes in piglets from Tenerife (Spain) and to assess their pathogenic potential by detecting toxin genes. A total of 140 samples were analyzed, including 58 fecal samples from slaughtered piglets (4–8 weeks old) and 82 rectal swabs from piglets aged 2–25 days. Samples were cultured, identified by MALDI-TOF MS, and characterized by PCR ribotyping and toxin gene detection. No isolates were obtained from fecal samples collected at slaughter, whereas 14 (17%) rectal swabs were positive. Colonization was strongly age-dependent, with the highest prevalence at 2 days of age (100%), decreasing by day 9 (10.7%), and absent after 21 days (p < 0.05). All isolates were ribotype RT033 with a tcdA⁺/tcdB⁻/cdtA⁺/cdtB⁺ profile. The exclusive detection of RT033, a clade V lineage linked to animal reservoirs and occasional human infections, suggests a potential zoonotic risk, especially for farm workers. These findings reinforce the need for integrated C. difficile surveillance under a One Health framework to monitor emerging ribotypes and their role in community-acquired infections.