Frequency of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) in non-clinical Enterococcus faecalis and Enterococcus faecium strains

Abstract

The fidelity of the genomes is defended by mechanism known as Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) systems. Three Type II CRISPR systems (CRISPR1- cas, CRISPR2 and CRISPR3-cas) have been identified in enterococci isolates from clinical and environmental samples. The aim of this study was to observe the distribution of CRISPR1-cas, CRISPR2 and CRISPR3-cas in non-clinical strains of Enterococcus faecalis and Enterococcus faecium isolates from food and fecal samples, including wild marine animals. The presence of CRISPRs was evaluated by PCR in 120 enterococci strains, 67 E. faecalis and 53 E. faecium. It is the first report of the presence of the CRISPRs system in E. faecalis and E. faecium strains isolated from wild marine animal fecal samples. The results showed that in non-clinical strains, the CRISPRs were more frequently detected in E. faecalis than in E. faecium. And the frequencies of CRISPR1-cas and CRISPR2 were higher (60%) in E. faecalis strains isolated from animal feces, compared to food samples. Both strains showed low frequencies of CRISPR3-cas (8.95% and 1.88%). In conclusion, the differences in the habitats of enterococcal species may be related with the results observe in distribution of CRISPRs systems.

Prevalence of CRISPR-Cas Systems and Their Possible Association with Antibiotic Resistance in Enterococcus faecalis and Enterococcus faecium Collected from Hospital Wastewater

“…In this study, the prevalence of CRISPR1 was higher in E. faecalis (50.0%) than E. faecium isolates (28.6%) that was similar to Lyons et al 31 In the current study, the frequency of CRISPR-Cas systems was significantly higher in E. faecalis (80.0%) than E. faecium (40.0%). This finding was in line with a previous report by Huescas et al 29 from Brazil, who found that the CRISPR-Cas elements of E. faecalis were detected more often than those of E. faecium in non-clinical samples. However, they reported more and less prevalence of CRISPR2 and CRISPR3-cas in the E. faecalis and E. faecium isolates from food and animal fecal samples than in our study, respectively.…”

“…A previous study by Dos Santos et al, 14 showed a lower frequency rate (51.1%) of CRISPR-Cas in enterococci collected from human and food sources. Using PCR, the frequency of CRISPR2 (55.3%) was higher than CRISPR1 (41.2%) and CRISPR3 (35.3%) in this study which was in line with previous reports by Gholizadeh et al 11 from Iran and Huescas et al 29 from Brazil. In contrast to our results, Dos Santos et al 14 reported CRISPR3 (67.4%) as the most prevalent type in enterococci isolates.…”

“… 32 Also, this research showed the prevalence of 28.6%, 22.9%, and 4.3% for CRISPR1, CRISPR2, and CRISPR3 in E. faecium isolates, respectively. In this regard, Huescas et al 29 reported a higher prevalence rate of CRISPR2 (32.7%), but lower frequency of CRISPR1-cas (5.6%) and CRISPR3-cas (1.8%) genes in non-clinical E. faecium isolates. These discrepancies in the results of various studies can be due to the sample size, the source of the sample collection, and the technique used in the screening of CRISPR-Cas systems.…”

Association of CRISPR-Cas System with the Antibiotic Resistance and Virulence Genes in Nosocomial Isolates of Enterococcus

“…In the current study, we found that the presence of orphan CRISPR2(42%) was more in Enterococcus than CRISPR1-Cas (23%) and CRISPR3-Cas (5%), which was similar to Alduhaidhawi. 28 In non-clinical Enterococcus faecium isolates, Huescas et al 29 demonstrated a higher prevalence rate of CRISPR2 and lower frequency of CRISPR1-Cas (5.6%) and CRISPR3-Cas (1.8%) system. In contrast to our study, Palmer et al 30 found that CRISPR2 was present in all Enterococcus faecalis isolates.…”