Vancomycin-Resistant Enterococcus (VRE) refers to a number of bacterial strains of the enterococcus genus which have developed a resistance to certain antimicrobial agents including the antibiotic vancomycin. Strains will display one of six identified types of resistance, identifying the type of strain involved in infection is critical in order to determine proper treatment. Strains vary in their resistance to particular antibiotics. All but one of the six strains are uniformly resistant to vancomycin, the exception being Van-C which exhibits only partial resistance. Van-A is significant in that it is resistant not only to vancomycin but also to teicoplanin. The remaining strains have varying susceptibility to other antibiotics.
Enterococci bacteria live benignly on human skin, female genitals and in the intestines, however, it is possible for these bacteria to invade the urinary tract, bloodstream, surgical wounds or sites of catheters. Those have recently been treated with vancomycin or other antibiotics at a higher risk for developing a VRE infection. Some have classed VRE as a "superbug" because of its considerable acquired antibiotic resistance. The CDC estimates that there are over 66,000 cases of nosocomial enterococcus infections among the ill and injured annually. Just under one-third of these are vancomycin resistant. Approximately 1 in every 20 people infected with VRE will succumb to the infection.
Like many bacteria, VRE can be spread through casual human contact or contact with contaminated objects. Most commonly, VRE bacteria are spread from the hands of healthcare provider to patient and transmission is common in health care facilities and nursing homes. Unless a patient acquires exceptionally rare VRE pneumonia, the bacteria will typically not be transmitted or carried through the air like cold/flu viruses and specific bacteria.
Healthy people with able immune systems will usually not develop VRE infection, even if VRE is present in their systems. Those with weakened immune systems or who have recently undergone surgery are at a greater risk of developing an infection.The causes of VRE remain somewhat cloaked in ambiguity, as it is still unclear to scientists why some people become infected by the bacteria and others do not, given its prevalence on the skin and in intestines. The only clear causation identified is taking antibiotics for a long period of time.
It is, however, generally a hospital-acquired/nosocomial infection - one whose incidence may be reduced and managed with proper hygienic methods and the diligence of hospital staff.
Depending on the site of infection, symptoms of VRE will vary. Infection may develop where catheters have been used, in the urinary tract, bloodstream or surgical wounds.
For catheter/surgical wound infections, symptoms include:
- Fluid leakage
- Red, warm skin around wound
- Soreness and swelling at wound site
Bloodstream infection symptoms may include:
- Body aches
- Rapid pulse and breathing
- Nausea and vomiting
- Decreased urination
Urinary tract infections may be accompanied by:
- Frequent or intense urge to urinate
- Pain or burning sensation while urinating
- Cloudy, dark, bloody, or foul-smelling urine
- Lower back or abdominal pain
The symptoms of VRE do not benefit from a great deal of specificity, especially since sepsis (bloodstream infection), UTI, and catheter site infection can be the result of a great many bacteria. Therefore it is essential for health care providers to obtain a sample from the site of infection, blood, or urine to determine what bacteria is the culprit and furthermore what strain.
It is crucial to isolate individuals who have a confirmed case of VRE, as this can help reduce its spread. The chief difficulty in treating a case of VRE is that the bacteria display resistance to so many antibiotics. However, antibiotics are still the only means of beating the infection and will be administered to the patient, either orally or intravenously. A cocktail of more than one antibiotic may be given to quell the infection. Regular samples of blood, urine, and stool will be sent for lab work until the patient is no longer infected. The immune system may be able to rid itself of a VRE infection as it regains its strength, post-surgery for example.
There are a number of risk factors which place someone at greater risk of developing a VRE infection. Anyone who has been treated recently with the antibiotic vancomycin is at greater risk, Those who are benignly colonized by VRE stand at a greater risk as well. Weakened patients, for example, those in ICU, cancer or transplant wards are more susceptible to VRE. Those who have undergone chest or abdominal surgery are also more at risk. Patients requiring indwelling devices such as catheters or IVs may develop infection at the catheter/IV site.
Prevention in Hospitals
Like all other catheter-associated infection, the risk of infection may be reduced by minimizing the use of all indwelling devices, as this reduces the amount of time the bacteria have to proliferate and cause infection. Hospital staff treating VRE-infected patients should handle the patient with exceptional caution, taking care to wear gloves and gowns to avoid direct contact until the patient is cured. Although the VRE bacterial infections may originate from the person's own bacterial flora, there are an increasing number of cases in which the bacteria was transmitted to the patient by an outside source whether it be hands of personnel or contaminated surfaces.
The CDC has issued a set of recommendations to prevent the spread of VRE, which has seen a "rapid increase" in the number of cases since 1989. Beyond the threat of infection, there is also the issue that VRE bacteria could transfer vancomycin resistant genes to other gram-positive microorganisms, such as Staphylococcus aureus.
As a first measure of prevention, the antibiotic vancomycin which is a known risk factor to developing VRE infection should be prescribed prudently and sparingly by clinicians. Hospital staff should be educated as to the growing problem of vancomycin resistant bacteria and the need to control its spread. Hospital microbiology laboratories should promptly report any discovery of a vancomycin resistant organism in a patient's bodily sample. The implementation of the appropriate course of treatment should be immediate as should infection-control techniques to prevent person to person spread.