Determination of Virulence Factors in Clinical Multidrug Resistance Enterococci Isolates at Southeast of Iran

The enterococci are responsible for infections including bacteremia and endocarditis which are usually resistant to multiple antibiotics. This nosocomial agent probably harbors putative virulence factors which increases their capability to colonize hospitalized patients.
This study was aimed in order to find the frequency of various virulence factors in enterococci and their relationship with multidrug resistance (MDR).
The samples were collected from different hospital wards including; Intensive care unit (ICU), cardiac care unit (CCU), pediatrics department, internal wards, and transplantation. The isolates were detected by biochemical tests and in order to determine the antibiotic susceptibility pattern, disk diffusion agar (kirby-bauer) was accomplished. Then, MICs (Minimum inhibitory concentrations) of vancomycin were determined by E-test strips. For molecular examinations and detection of drug resistance genes, the simple polymerase chain reaction was used. The multiplex PCR was used in order to detect virulence factors.
Total of 85 isolates were obtained from one university teaching hospital in southeast of Iran. Approximately 95% of isolated which were from urine specimens and 34% of isolates were collected from pediatrics units at hospital. Tetracycline resistance (48%) has been observed with a high frequency and related to the tetM gene. Furthermore, eighteen isolates were recognized as MDR strains that carried vanA, aac (6)-Ie-aph (2)-Ia, ermB, and tetM genes. Among virulence factor genes, asa1 (69%) and gelE (55%) are more frequently observed in both species. In general, we found Enterococcus faecalis strains more prevalent. Also, E. faecium was related to antibiotic resistance genes in nosocomial infection.
The data was indicated a high prevalence of multiple antibiotics resistance genes with virulence determinants in enterococci and also considered resistant isolate in pediatrics unit. The current results can be recommended in order to change new strategies for antibiotic therapy, because this serious pathogen is important for treatment and eradication in hospitals. Furthermore, the biofilm formation was regulated and constructed by virulence determinants that could be a candidate for enterococcal treatment.