vancomycin - resistant enterococcus ( vre ) is an important pathogen among hospitalized patients . significant morbidity , mortality , and increased hospital costs have been associated with infections due to vre . detection of new cases of vre represents cross transmission via the hands of health care workers , contaminated equipment , and environmental surfaces . the emergence of de novo vre through genetic mutations induced by glycopeptide exposure in an individual patient is unusual . acquiring nosocomial vre may vary according to how endemic vre is in a specific location , the exposure to contaminated equipment , vre carrier proximity referred to as  colonization pressure ,  and patient 's hospitalization duration which is referred to as the  time at risk . colonization pressure is defined as the proportion of patients colonized with a particular organism in a defined geographic area within a hospital during a specified time period . differentiating among the factors associated with nosocomial spread of vre or amplification of previously undetectable colonization is difficult in clinical settings . the first report of vre from saudi arabia was in 1993 from king faisal specialist hospital - riyadh . however , there are only three studies of vre from saudi arabia . one study described the frequency of vre as normal flora of the intestine in saudi patients . the second study characterized 34 vancomycin - resistant vana e. faecium isolates obtained from two hospitals in saudi arabia . the third study describes the prevalence and risk factors for fecal carriage in patients at tertiary care hospitals . in that study , only 7 out of 157 rectal swabs obtained from patients in different clinical setting were vre positive . here , we report the result of the surveillance study of vre in a saudi arabian hospital and describe the associated risk factors for vre colonization and infection in our region . the goal of this study was to identify significant risk factors for acquiring vre colonization and infection in icu settings using a case - control study . this is a retrospective , case - control study of vre cases at king fahad specialist hospital - dammam , a referral hospital providing tertiary care for the province of dammam , saudi arabia . the hospital has 18 medical - surgical intensive care unit beds , and more than 6000 patients are admitted to king fahad specialist hospital - dammam annually . records obtained from the infection control section and the clinical microbiology laboratory were reviewed to identify icu patients who had vre ( e. faecalis or e. faecium ) isolated from either surveillance cultures or clinical specimens between february 2006 and march 2010 . king fahad specialist hospital - dammam does have guidelines for wide screening of new hospital admission for mrsa and vre to prevent outbreaks of these infections . intensive care unit , for example , performs active surveillance for methicillin - resistant staphylococcus aureus ( mrsa ) and vre at icu admission . medical records of patients with and without vre were reviewed , and the following information was collected ( as outlined in table 2).demographic data ( age , gender ) . host - related factors ( icu admission , acute renal failure , sepsis or multiorgan failure , and underlying diseases ) . hospital related factors : referral from other hospitals ; hospital admission in the previous year ; length of stay of previous year 's hospitalization icu length of stay . medication - related factors : use of antimicrobial agents in the past three months , duration of antibiotic use , use i d corticosteroid , chemotherapeutics , and cyclosporine . demographic data ( age , gender ) . host - related factors ( icu admission , acute renal failure , sepsis or multiorgan failure , and underlying diseases ) . hospital related factors : referral from other hospitals ; hospital admission in the previous year ; length of stay of previous year 's hospitalization icu length of stay . medication - related factors : use of antimicrobial agents in the past three months , duration of antibiotic use , use i d corticosteroid , chemotherapeutics , and cyclosporine . vre colonization or infection date is defined as the date on which a positive sample was collected . recent antimicrobial use was defined as receipt of any antimicrobial agent for more than 3 consecutive days in the 3 months before the date of culture detection ; patients who received short courses of perioperative prophylaxis were excluded by this criterion . renal insufficiency was defined as a creatinine concentration greater than 1.7  mg / dl . high risk icu room is a room of previous patients colonized or infected with vre . rectal swabs for culture were first inoculated onto columbia pnba and then into salt broth . plates were incubated at 35c in ambient air and examined for growth at 24 and 48 hours . any suspected colonies were identified by conventional laboratory methods , including gram stain , catalase test , bea test , and bvs ( vancomycin screening agar that incorporates the use of 6  ug / ml of vancomycin in brain - heart infusion agar ) . black colonies ( esculin positive ) were then subcultured onto a blood agar plate for purity . following 24 hours incubation , a definite spot of growth or greater than one colony present at the site of inoculation on the bvs agar indicates that the enterococci may be a vre . faecium ) was confirmed by performing gram - positive ( gp ) identification card on the vitek 2 system ( biomerieux ; gp colorimetric identification card ) . susceptibility testing was performed on confirmed enterococcal isolates using vancomycin ( 0.016 to 256  g / ml ) and teicoplanin ( 0.016 to 256  g / ml ) e test strips . the determination of the mics and the interpretation of vancomycin resistance ( mic  32  g / ml ) were done according to the clinical and laboratory standards institute ( clsi ) guidelines . for the interpretation of the teicoplanin results , combination of the intermediate and resistant mics was done as previously published for the assignment of isolates as having vana ( mic  16  g / ml ) or vanb ( mic < 16  g / ml ) . patients who had vre colonization or infection ( 30 cases ) were matched 1  :  2 to randomly selected controls who were patients in the same ward or unit during the study period . controls were selected in such a way that the distributions of case patients and control patients were similar over the dates of hospitalization . the controls were selected from the population of patients whose surveillance or clinical culture findings were negative for vre . during the study period , there were 2200 surveillance cultures obtained , and only 30 ( 1.4% ) distinct cultures were positive . we encoded all data into a database and used stata ( version 7 ) for analysis . we compared the characteristics of cases and controls using the chi - square test for categorical variables and the t - test for continuous variables . to investigate which potential risk factors were associated with vre , we performed unconditional logistic regression with adjustment for age , sex , and ward . odds ratios ( ors ) and corresponding 95% confidence intervals ( cis ) were used as summary statistics to assess risk . between february 2006 and march 2010 , a total of 30 patients in icu were identified with vre colonization or infection . table 1 shows the characteristics of cases and controls . as a result of the matching process , the distributions of cases and controls were similar in terms of age , sex . the case patients were more likely to have multiorgan failure upon icu admission ( 33% versus 12% , p = 0.03 ) , more likely having underlying chronic renal failure ( 43% versus 15% , p < 0.01 ) , receiving hemodialysis ( 37% versus 18% , p = 0.05 ) , or receiving gi contrast procedure ( 17% versus 2% , p = 0.03 ) . case patients were more likely to have received antimicrobial agents in the 3 months before the study period ( 69% versus 20% , p < 0.01 ) especially vancomycin , metronidazole , quinolones , and piperacillin - tazobactam . being on chemotherapeutic agents was observed in 10.7% of vre - positive versus 1.6% of vre - negative patients ( p value = 0.09 ) . of interest , it was found that being located in a high risk room ( roommate of patients colonized or infected with vre ) was protective ( table 2 ) . multivariate analysis showed that prior antibiotic use was an independent determinant for the acquisition of vre ( p = 0.026 ) . vancomycin - resistant enterococcus is becoming the causative agent in an increasing number of health - care - associated infections in the last decade especially in the united states . nowadays , vre is reaching middle east countries like saudi arabia , and to our knowledge , this is the second published study on the epidemiology and risk factors of vre from saudi arabia . also , vancomycin - resistant enterococci are becoming more important for hospital - infection control , mostly due to their particular features : colonization of the gastrointestinal tract , difficulty in decolonization of patients , and the environment dissemination . case - control study was performed comparing all known risk factors for vre colonization from the current literature , including high risk host with comorbidities including underlying diseases like chronic renal failure , diabetes mellitus , ischemic heart disease , congestive heart failure , liver failure , and liver cirrhosis ; hospital - related factors including hospital admission in previous year including icu , length of hospitalization , having special procedures during hospitalization , and insertion of devices ; and medication- related factors like the use of antimicrobial agents in the past three months [ 5 , 15 , 16 ] . univariate analysis of our data suggested that the potential risk factors for the new detection of vre were multiorgan failure upon icu admission , more likely having underlying chronic renal failure or receiving hemodialysis , was more likely to have received antimicrobial agents in the three months before the study period especially vancomycin , metronidazole , quinolones , and piperacillin - tazobactam . the association of colonization with renal failure suggests that patients who are more ill are more vulnerable to colonization with vre . numerous studies of both colonized and infected patients explored the role of preceding antimicrobial treatment as a risk factor for nosocomial vre with conflicting results . it was suggested that previous use of vancomycin , cephalosporins , and antimicrobial agents with an antianaerobic spectrum is important in the development of vre . our study showed similar data regarding prior exposure to vancomycin , metronidazole , piperacillin - tazobactam , and quinolones as a major risk factor for the development of vre . it is interesting to note that being located in a high risk icu room ( roommate of patients colonized or infected with vre ) was protective . however , it was shown previously that roommates of patients identified as colonized or infected with vre were at substantial risk of becoming colonized , with the degree of risk increasing in older and more frail patients . molecular typing of the isolates from this outbreak revealed that the predominant vre comprised 20  vanb , five vana , and one vana / vanb type isolates , which tended to fall into two genetic clusters that were identifiable phenotypically by their susceptibility to tetracycline . in conclusion , the factors associated with acquisition of vre are often complex , may be confounded by local variables , and may be different depending on whether the patient acquires vre by nosocomial transmission or by primary in vivo emergence ( e.g. , gene transfer to previously susceptible enterococci ) . our study suggests that strict infection control and isolation procedures are effective in controlling health - care - associated transmission of vre , as it was shown that being in a high risk room ( room of previous patients colonized or infected with vre ) was protective . this observation is likely related to more vigilant postdischarge cleaning and disinfection of these rooms . one limitation of the study is the small sample size , but vre is not common in saudi arabia .
background . 
 vancomycin - resistant enterococci ( vre ) are significant nosocomial pathogens worldwide . 
 there is one report about the epidemiology of vre in saudi arabia . objective . to determine the risk factors associated with vre infection or colonization in intensive care unit ( icu ) settings . design . 
 this is a descriptive , epidemiologic hospital - based case - control study of patients with vre from february 2006 to march 2010 in icu in a tertiary hospital in saudi arabia 
 . methods . 
 data were collected from hospital records of patients with vre . 
 the main outcome measure was the adjusted odds ratio estimates of potential risk factors for vre . results . 
 factors associated with vre included icu admission for multiorgan failure , chronic renal failure , prior use of antimicrobial agents in the past three months and before icu admission , gastrointestinal oral contrast procedure , and hemodialysis . being located in a high risk room ( roommate of patients colonized or infected with vre ) was found to be protective . 
 conclusions . factors associated with vre acquisition are often complex and may be confounded by local variables .