Antibiotic Resistance and Biofilm-Forming Ability in Enterococcal Isolates from Red Meat and Poultry Preparations

Abstract

This study investigated the resistance to antibiotics and the capacity to form a biofilm of 200 isolates of enterococci isolated from raw preparations of beef (51 strains), pork (47), chicken (50), and turkey (52) acquired in north-western Spain. Fifteen antimicrobials of clinical importance were tested by the disc diffusion method. The average number of resistances per strain was 4.48 ± 1.59. If resistant strains were taken together with those showing reduced susceptibility, the total number of resistances per strain was 6.97 ± 2.02. Two isolates (1.0% of strains) were resistant to a single antibiotic, twenty-two isolates (11.0%) presented resistance to two, one strain (0.5%) was resistant to three, and 175 isolates (87.5%) showed a multiple drug-resistant phenotype (MDR; defined as no susceptibility to at least one agent from each of three or more antimicrobial categories). The prevalence of resistance varied between 0.5% (gentamicin) and 100% (kanamycin). All strains produced biofilm on polystyrene microwell plates, determined using crystal violet assay. Isolates were classified as having a weak (51 strains; average optical density at 580 nanometers -OD580- = 0.206 ± 0.033), moderate (78 strains; average OD580 = 0.374 ± 0.068), or strong (71 strains; average OD580 = 1.167 ± 0.621) ability to produce biofilm (p < 0.05). Isolates from beef preparations produced the most substantial (p < 0.05) biofilms. The results of this study indicate that meat and poultry preparations are major reservoirs of antibiotic-resistant enterococcal strains capable of forming a biofilm. In order for food-borne infections to be prevented, the importance of careful handling of these foodstuffs during preparation, avoiding cross-contamination, and ensuring thorough cooking, is stressed.

Detection of virulence factors, biofilm formation, and biogenic amine production in vancomycin‐resistant lactic acid bacteria (VRLAB) isolated from foods of animal origin

“…Previous studies showed that biofilm production is common in Enterococcus isolates from different origin (Baldassarri et al, 2001; Castaño‐Arriba et al, 2020; Goudarzi et al, 2018; Igbinosa & Beshiru, 2019), as confirmed in this study. Baldassarri et al (2001) reported strong biofilm production in 43% of their E. hirae , E. durans , E. casseliflavus , E. gallinarum , E. raffinosus , and E. avium isolates.…”

“…Igbinosa and Beshiru (2019) indicated that 12, 19, and 37% of Enterococcus species from shrimps were strong, weak and moderate biofilm producers, repectively. Castaño‐Arriba et al (2020) found that 51, 78 and 71 of 200 enterococci from red meat and poultry preparations were weak, moderate and strong biofilm producers, respectively. In contrast to our data, some researchers found no biofilm formation in their E. casseliflavus and E. gallinarum isolates (Chajęcka‐Wierzchowska et al, 2016; Dworniczek et al, 2003; Gomes et al, 2008).…”

Antimicrobial Resistance, Biofilm Formation, and Virulence Genes in Enterococcus Species from Small Backyard Chicken Flocks

“…MDR was frequently detected among the isolated enterococci in this study. The emergence of MDR enterococci has also been reported worldwide, particularly in Korea (26.9%), Spain (87.5%), and Ethiopia (78.2%), and is currently regarded as a growing public health concern [72][73][74].…”

Current Trends of Enterococci in Dairy Products: A Comprehensive Review of Their Multiple Roles

“…Regarding E. durans and E. faecium isolates, resistance to penicillin, erythromycin, tetracycline, levofloxacin, norfloxacin, ciprofloxacin, chloramphenicol, and nitrofurantoin was reported (Table 2). Resistance to the latter three is of concern, for not being intrinsic in enterococci, and they are regarded as essential antibiotics for humankind [299,300]. Despite the presence of tetM, tetracycline resistance was not reported in E. faecium as per these studies.…”