annually since 1990 , the infectious diseases program office for va central office has distributed an infectious diseases / infection control survey to all va medical center reporting sites across the country that request data on several topics . the process for the survey begins with the distribution of the annual survey instrument ( questionnaire ) to each va medical center reporting site ; this is delivered to the administrator responsible for the facility . each site notes a point of contact for subsequent data verification . after the 2-week period , the ability to access the database for entry is closed to the medical center reporting sites . administrative review by the infectious diseases program office identifies medical centers that have omitted data . the point of contact is queried ( either by telephone or e - mail ) as to the nature of the omission . concomitant with the review of data for omission , a preliminary analysis of the submitted data is undertaken to assess for accuracy of other reported data and consistency of reporting with previously submitted data from the medical center . there are several questions in the infectious diseases / infection control annual survey that serve as controls for analysis . if there is concern that the submitted data may be inaccurate , the point of contact for the site is also queried to verify these data . beginning in 1998 ( for fy 1997 data ) , the survey included two questions regarding sarv . the following questions were asked , 1 ) does your facility do or obtain testing to identify reduced susceptibility to vancomycin ( mic > 4 g / ml ) for staphylococcus aureus ? yes or no ? 2 ) if yes , report the number of patients ( not cultures ) with staphylococcus aureus with reduced susceptibility to vancomycin ( mic > 4 g / ml ) . any site reporting presence of a patient with sarv was contacted by the infectious diseases program office to verify accuracy of the report for both fy 1997 and 1999 data . during the contact by the infectious diseases program office ( january 2001 ) for fy 1999 data , this additional information included verification that the isolate was indeed s. aureus , identification of the susceptibility testing methods , source of the specimen , inpatient or outpatient status at the time of specimen acquisition , and mic to vancomycin . query was also made regarding confirmatory testing of vancomycin susceptibility of the patient isolate , susceptibility testing to other antimicrobial agents , and current availability of the isolate . for fy 1997 , there was 100% response to the survey instrument ( 146 reporting sites ) , although not all questions were completed . after contact and verification of the survey results by the infectious diseases program office with these sites , seven patients were reported to have sarv from four of the sites . rationale for discounting initially reported cases after verification included misinterpretation of the question to be requesting information on vre or misinterpretation of the question to mean mrsa . for fy 1999 , there was 99% response to the survey instrument ( 142 of 143 reporting sites ) , though not all questions were initially completed . with regard to the ability of the reporting facility to do or obtain testing to identify sarv , 142 reporting sites answered this question , with 123 ( 86% ) of the sites responding  yes . of the 123 sites reporting yes , initially 13 sites reported 195 patients with sarv . after contact and verification by the infectious diseases program office , the number of verified , reported cases was revised to eight sites reporting 19 patients with sarv . reasons for change of reported numbers to verified numbers included misinterpretation of the question to mean mrsa as well as one isolate with a difficult determination by the original mic method used ( reporting an mic > 16 g / ml ) but with confirmatory testing defining an mic = 1.5 g / ml . microbiology testing was noted to be done onsite in a cap - approved laboratory for all reported and verified cases . the specimen sources for these isolates were five from tissue or wounds , five from a urinary source , four from sputum , two from abdominal or peritoneal sources , and one each from blood , eye , and synovial fluid . initial susceptibility testing showed 17 used microscan technologies ( dade behring , inc , microscan division , west sacramento , ca ) and one each of biomerieux vitek ( hazelwood , mo ) , and e - test ( ab biiodisk north america , inc , piscataway , nj ) ( table 1 ) . confirmatory testing was done on only 2 of the 19 reported cases , using e - test and microscan technology ( table 1 ) . one isolate was sent to cdc for confirmation . however , as noted above , confirmatory testing had also been done on at least one occasion to refute presence of sarv . sixteen of the isolates were reported to have an mic = 4 g / ml , one was reported to have an mic = 8 g / ml ( noted to be an intermediate sensitivity interpretation ) , one was reported at > 16 g / ml , while one was reported at > 32 g / ml ; these last two isolates were interpreted as being resistant . six of these specimens were obtained from patients during an outpatient encounter , while seven were obtained while patients were on inpatient status , and five were from patients in a nursing home . only one of the 19 case isolates had been stored and is available for further analysis . biomerieux vitek ( hazelwood , mo ) , e - test ( ab biodisk north america , inc . , piscataway , nj ) , microscan ( dade behring inc . , microscan division , west sacramento , ca ) . where data were available , software version of technology provided . susceptibility interpretation at the reporting site ( s = sensitive , i = intermediate , r = resistant ) . icu = intensive care unit . reported susceptibility testing to other antimicrobial agents are noted in table 2 and table 3 where data were available ; not all isolates had susceptibility testing done against all antimicrobial agents reported . beta - lactamase activity was present for 14 of the 16 isolates . for penicillin - type antibiotics , 12 of the 19 isolates had oxacillin resistance . there was also a relatively high degree of resistance to the cephalosporins tested ( data not shown ) and six of eight isolates were resistant to imipenem . antibiotic susceptibility testing against other agents used to treat gram - positive infections showed varying degrees of resistance , with 4 of 15 isolates resistant to rifampin , 14 of 18 resistant to erythromycin , 11 of 17 resistant to clindamycin , 4 of 17 resistant to tetracycline , only 1 of the 19 isolates resistant to trimethoprim / sulfamethoxazole , and none of 4 isolates resistant to chloramphenicol . for the quinolones and other agents , 5 of 16 were resistant to ciprofloxacin , 4 of 5 were resistant to levafloxacin , 4 of 7 were resistant to ofloxacin , and 3 of 16 were resistant to gentamicin . ffy = federal fiscal year ; s = susceptible , i = intermediate and r = resistant based on laboratory interpretative criteria . the authors took the liberty of placing interpretation on some reported mic values that did not have an interpretation of s , i , or r on information provided from the facility . ffy = federal fiscal year ; s = susceptible , i = intermediate and r = resistant based on laboratory interpretative criteria . in this survey , patients were reported to have sarv in the va system for both fys 1997 and 1999 . comparison of the two surveys indicates an increase of 170% in the number of cases reported in 1999 compared with 1997 . this finding is in contradistinction to information reported by mrl pharmaceutical services , where none of 3,797 s. aureus isolates had reduced susceptibility to vancomycin in 1999 ( 15 ) . even though different methods of data accrual were used , both surveys rely on nccls - based susceptibility criteria ( 10 ) . despite the fact that presence of sarv appears to be a low - incidence occurrence at this time , the reason for different occurrences of sarv between the va and this other national data set ( 15 ) is not readily apparent from the data present . the difference of findings , even though both use nccls - based susceptibility criteria , may be based on the fact that the mrl study used one consistent microbroth dilution method for susceptibility testing whereas our population - based reporting survey encompasses numerous susceptibility testing methods ( microscan , vitek , e - test , screening plates ) more analogous to real - world application of technologies . tenover et al . ( 11 ) demonstrated different methods of susceptibility testing ( e.g. , microscan rapid panels and disk diffusion ) have been shown to be unreliable in detecting s. aureus strains with reduced susceptibility of vancomycin ; none of the va laboratories reporting sarv used those methods considered to be unreliable ( table 1 ) . sampling size may be a factor , as we do not have the total number of isolated tests nationwide in the va , but the total number likely exceeds the number of isolates in the mrl study . different populations sampled or the recent cdc studies indicating difficulty in delimiting antibiotic resistance ( 13,14 ) might all contribute to this difference as well . because of limitations in our survey methods , we are unable to supply information on the total number of s. aureus isolates ( or persons with s. aureus isolated ) within the va system nationwide , from which to determine prevalence estimates for comparative purposes to other studies ( 16,17 ) . data from wilcox et al . and aucken et al . indicate that about 15% of isolates in the united kingdom had a vancomycin mic of 4 g / ml on initial testing ( 16,17 ) . these two reports also indicate a low prevalence of vancomycin ( glycopeptide)-intermediate or -resistant isolates upon confirmation . the reports also lend support to the finding that susceptibility testing of s. aureus to vancomycin by disk diffusion , which is commonly used in the united kingdom , is not as reliable as other methods of testing for reduced susceptibility of s. aureus to vancomycin ( 11 ) . for each of the 2 years surveyed , more sites initially reported patients with sarv than were present after verification by the infectious diseases program office . the most common reason noted for the inaccurately reported data was misinterpretation of the question to mean mrsa , indicating that despite a simply worded question giving specific definitions , data validation is important . validation is especially important for low - incidence diseases , for which a few misreported cases may significantly alter the final outcome . despite cdc recommendations on confirmatory testing of suspect if confirmatory testing is being performed , it is not being recorded ; therefore , it is not reported in this retrospective review . further , from the survey we were not able to determine if confirmatory testing of the isolate to indeed be s. aureus was occurring . however , each site did note that it was confident of the organism identification . perhaps of greater importance is the recognition that despite cdc recommendations for confirmatory testing to be done for isolates of staphylococci with mics > 4 g / ml to vancomycin , the infectious diseases program office was informed by several of the sites reporting sarv that an mic of 4 g / ml was interpreted as susceptible by nccls criteria ; ( 10 ) therefore , it was not necessary to confirm this result . the lack of confirmatory testing indicates poor recognition for the significance of s. aureus having the potential for reduced susceptibility to vancomycin . also , only one site ( of eight sites in fy 1999 ) reported contacting a public health authority about a sarv isolate ( i.e. , sent to cdc for confirmatory testing ) , again indicating a lack of recognition of important public health service recommendations . no other reports indicate the extent of adherence to such national recommendations about sarv . even though this lack of recognition and reporting is not the same as the capacity to detect antimicrobial resistance , it is analogous to cdc findings that confirmation of susceptibility for suspected sarv was as low as 39% ( 13 ) . upon review of other antimicrobial susceptibilities of the 19 sarv cases from fy 1999 , a high degree of resistance to other agents was found ; however , a third of isolates were noted to be susceptible to oxacillin or methicillin . some reports indicate that coagulase - negative staphylococci also have reduced susceptibility to vancomycin ( 18 ) . given the limitation to two basic questions imposed by the infectious diseases / infection control annual survey methods , the full extent and characterization of s. aureus with reduced susceptibility to vancomycin in the va can not be accurately assessed . however , this method has indicated that sarv exists in the va health - care system , the occurrence of which has increased between the 2 years reviewed . this study also identified the importance of data validation as evidenced by misinterpretation of clearly stated and defined questions . with the presence of this organism and its apparent increase in occurrence , a more thorough analysis of the extent and characteristics of this organism in the va system would be beneficial to both va and public health in general ; this analysis might include patient characteristics , antibiotic use in patients before acquisition of sarv , and collection and storage of isolates for further laboratory analysis . along with further characterization of the epidemiology of this organism , increasing awareness as to the significance of sarv is indicated .
a national survey was sent to all appropriate veterans health administration ( va ) medical facilities asking abut the ability to test for staphylococcus aureus with reduced susceptibility to vancomycin ( sarv ) ( mics > 4 g / ml ) . 
 also , a request was made for the number of patients having sarv isolated during a 1-year period . 
 nineteen patients from eight sites across the country had isolation of sarv . 
 of these , microscan ( dade behring , inc , microscan division , west sacramento , ca ) technology was used for 17 patients , vitek ( hazelwood , mo ) was used for 1 of the remaining 2 patients , and e - test ( ab biiodisk north america , inc , piscataway , nj ) for the other . 
 all patients with this organism had microbiology testing done onsite in the reporting va facility s college of american pathologists - approved laboratory . for comparison , 
 similar data were obtained for a 1-year period 2 years prior to the current survey ; seven patients from four sites were verified to have a sarv . between the two survey periods the reported cases of sarv increased 170% , indicating a need for continued surveillance and potentially a need to initiate a collection of isolates for further analysis .