2. Universidad Cardenal Herrera-CEU

The widespread irrational use of antibiotics in recent years has resulted in an increase in the detection of multi-resistant bacterial strains, particularly methicillin-resistant Staphylococcus aureus (MRSA). The use of natural derivatives such as flavonoids is postulated as one of the most promising avenues to solve this emerging public health problem. The objective of the present study is to characterize the antimicrobial activity of icariin, a flavonoid compound isolated from a variety of plants of the Epimedium genus, against human and animal clinical MRSA isolates. Our study found that icariin alone did not have any antimicrobial effect on S. aureus or MRSA clinical isolates. However, icariin enhanced the effect of amoxycillin-clavulanate or ampicillin, whereas no effect was seen when used in combination with vancomycin. Specifically, co-incubation of S. aureus with amoxycillin-clavulanate plus icariin resulted in an increased proportion of dead cells, suggesting that this flavonoid potentially increases antimicrobial activity when used in combination with the beta-lactam antibiotic amoxycillin-clavulanate. Furthermore, we demonstrate that co-incubation of S. aureus with AmoxyClav plus icariin resulted in increased membrane disruption and growth inhibition. This study demonstrates the potential utility of icariin in permitting lower antibiotic therapeutic doses in alignment with strategies to reduce the spread of antibiotic resistance. Further research is required to determine the optimum concentration of icariin and to define clinically relevant combinations of flavonoid and antibiotic.

The appearance of methicillin-resistant strains of Staphylococcus aureus (MRSA) in several animal species (including rabbits) has set o alarms for their capacity to act as reservoirs for this bacterium. This is especially important in wild animals given its epidemiological implications. The objectives of this study were to identify and characterize S. aureus, specifically MRSA, strains in wild lagomorph high-density areas. Ten hares and 353 wild rabbits from 14 towns with a high rabbit density in the Valencian region (eastern Spanish coast) were sampled. Swabs from the nasal cavity, ears, perineum and lesions (when present) were taken for microbiological studies. The detection of di erent genes and antibiotic susceptibility studies were also carried out. Of all the animals, 41.3% were positive for S. aureus, of which 63.3% were MRSA. Ears were the anatomical location with more S. aureus and MRSA strains. The more frequently identified MLST type was ST1945 (97.1%, 136/140). The mecA gene was found only in one sample. The rest (n = 139) carried the mecC gene and were included in CC130, except one. Penicillin resistance was detected in 28 mec-negative isolates and, in one case, bacitracin resistance. mecA isolate presented resistance to enrofloxacin and tetracycline, and 10 mecC isolates also showed bacitracin resistance. No MRSA isolate was positive for genes chp, sea, tst and PVL. Two ST1945 isolates contained IEC type E (comprising genes scn and sak). mecA-isolate was positive for blaZ. Of the 28 MSSA strains showing resistance to penicillin, 22 carried the blaZ gene. These surprising results highlight the marked presence of MRSA strains in wild rabbits in high-density areas.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is an emerging problem in many parts of the world. Although animal-adapted LA-MRSA has been known for many years, recent reports suggest a possible increasing trend in the zoonotic transmission of LA-MRSA in Europe. Since its emergence in the early 2000’s, several investigations have indicated that persons in prolonged, repeated contact with affected livestock are at a higher risk of becoming colonized with LA-MRSA. LA-MRSA monitoring in livestock is voluntary under current EU legislation, and not all member states, including the UK, participate. UK LA-MRSA isolates have been detected through scanning surveillance, where samples are submitted from clinically diseased livestock for diagnostic investigation, and research studies. Surveys conducted on retail beef, pig and poultry meat on sale in the UK have also detected LA-MRSA. Taken together these results suggest that LA-MRSA is present in the UK, possibly at low prevalence level, as suggested by available evidence. In this review, we examine the data available from UK livestock and animal products, and make recommendations for future. We also review the findings from whole genome sequencing (WGS) of the possible lineage of some UK livestock isolates

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have been a growing problem in human medicine since the 1960s, and more recently in veterinary medicine with the appearance of livestock-associated MRSA (LA-MRSA). Nevertheless, information about the presence of MRSA in rabbits is quite scarce since only one LA-MRSA identification has been previously reported. The present study aimed to determine genotypic characterization by verifying the presence of resistance determinants, virulence, and toxin genes of different S. aureus strains that cause lesions in rabbits, and their phenotypic traits based on the antimicrobial susceptibility profile. The analysis of 240 S. aureus isolates obtained from different lesion types collected from 89 Spanish and Portuguese rabbit commercial farms in the last 4 years (2014–2017) was performed. The methicillin-resistant gene mecA was found in 11.25% of the studied isolates (27 of 240) from 19 farms (13 Spanish and 6 Portuguese). Staphylococcal cassette chromosome mec (SCCmec) typing predominantly revealed type III (n = 15). Additionally, three MRSA isolates carrying the mecC gen were detected in samples from three different farms (two Spanish and one Portuguese). None of the 30 MRSA isolates was PVL-positive or tst-positive. After the multilocus sequence typing (MLST) procedure, 16 belonged to ST2855, 6 to ST146, 6 to ST398, and 2 ST4774. No ST121 isolate was mec-positive. ST398 and ST4774 isolates lacked the immuneevasion-cluster (IEC) genes. ST2855 strains were associated with the presence only of the sak gene, and ST146 isolates were ascribed to IEC type E. Therefore, this is the first description of LA-MRSA from rabbits belonging to ST2855. Interestingly, one ST2855 and two ST4774 isolates were mecC-positive, which could act as a mecCMRSA reservoir. More studies are needed to further characterize these isolates and their relationship with humans and other animal species.