The Prevalence of Fecal Colonization of Enterococci, the Resistance of the Isolates to Ampicillin, Vancomycin, and High-Level Aminoglycosides, and the Clonal Relationship Among Isolates

Abstract

The gastrointestinal tract carriage of enterococci was searched in 150 hospitalized patients and 100 outpatients, and clonal relatedness of the isolates and their resistance to ampicillin, vancomycin, and high-level streptomycin and gentamicin were investigated. A stool sample or rectal swab collected from each patient was inoculated into appropriate media within an hour. Enterococcus species were identified by using conventional biochemical tests, API-20 Strep assay, and BBL crystal kit. Antibiotic susceptibility tests were performed using Kirby-Bauer disk diffusion method. A polymerase chain reaction (PCR) was used to detect vanA and vanB genes. Pulsed-field gel electrophoresis (PFGE) and arbitrarily primed-polymerase chain reaction (AP-PCR) methods were used for molecular typing of the strains. Enterococci were isolated from 90 (60%) of the specimens collected from 150 inpatients. Of these 90 isolates, 37 (41%) had high-level gentamicin resistance, 36 (40%) had high-level streptomycin resistance, and 50 (55.6%) had ampicillin resistance. Fecal colonization was found in 30% of the outpatients. Resistances to ampicillin, high-level streptomycin, and gentamicin were 13%, 10%, and 3%, in these patients' isolates, respectively. No vancomycin-resistant enterococci were detected by both agar diffusion and PCR assays in our study. Both typing procedures were applied on 78 Enterococcus strains isolated from inpatients. AP-PCR typing showed that 30 (50.8%) of the 59 E. faecium and 5 (50%) of the 10 E. faecalis strains were clonally related. These values were found to be 12 (20.3%) and two (20%) by PFGE, respectively. The typing procedures did not find any clustered strains in the six E. durans and three E. avium isolates. Neither PFGE nor AP-PCR result was significantly different among the sensitive and resistant strains. Our results indicate that the high prevalence of colonization with ampicillin and highlevel aminoglycoside-resistant enterococci is an important problem in our medical center. The high clonal diversity among the isolates indicates limited spread of antibiotic-resistant strains between patients.

Enterococcus cecoruminfections in broiler breeders and their offspring: molecular epidemiology

“…Genetic relatedness of E. cecorum isolates originating from the broiler and broiler breeder flocks was studied using PFGE analysis. It was performed on isolates from the pericardium (n023), bone marrow (n 016) and joint (n03) from 10 different broiler flocks and, in addition, on isolates from the cloaca (n031), blood (n02), bone marrow (n01) and oviduct (n02) from nine different broiler breeder flocks, following the modification of a procedure described previously (Kuzucu et al, 2005). Briefly, colonies were collected from blood agar plates and resuspended in EET buffer (100 mM Na 2 EDTA, 10 mM EGTA and 10 mM TrisÁHCl) to an optical density between 1.2 and 1.4 measured at 600 nm.…”

Safety Evaluation and Antibacterial Activity of Enterococci Isolated from Lighvan Cheese

“…Therefore, the genus has not been yet considered as "generally recognized as safe" (GRAS) (Nallapareddy et al 2008). Enterococci have been implicated in the cause of nosocomial infections, bacteremia, endocarditis and infections of urinary tract with E. faecalis and E. faecium being the most common (Morrison et al 1999;Kuzucu et al 2005). Antibiotic resistance along with possessing multiple virulence factors such as resistance to host defense mechanisms and colonizing the host gastrointestinal tract, overgrowth and translocation result in enterococcal infections.…”

SNP diversity of Enterococcus faecalis and Enterococcus faecium in a South East Queensland waterway, Australia, and associated antibiotic resistance gene profiles

“…Certain members of the genus, particularly E. faecalis and E. faecium , are becoming increasingly important as opportunistic pathogens [7,12,13]. Most important and a contributing factor to the pathogenesis of enterococci is their resistance to a wide range of antibiotics [14]. Enterococci have been found to be increasingly resistant to multiple anti-microbial drugs in last few years [15-17].…”