The emergence of decreased susceptibility to vancomycin in Staphylococcus epidermidis.

BACKGROUND: Coagulase-negative staphylococci (CNS) are the major cause of nosocomial bloodstream infection. Emergence of vancomycin resistance among CNS is a serious public health concern, because CNS usually are multidrug-resistant, and glycopeptide antibiotics, among which only vancomycin is available in the United States, are the only remaining effective therapy. In this report, we describe the first bloodstream infection in the United States associated with a Staphylococcus epidermidis strain with decreased susceptibility to vancomycin. METHODS: We reviewed the hospital's microbiology records for all CNS strains, reviewed the patient's medical and laboratory records, and obtained all available CNS isolates with decreased susceptibility to vancomycin. Blood cultures were processed and CNS isolates identified by using standard methods; antimicrobial susceptibility was determined by using minimum inhibitory concentration (MIC) and disk-diffusion methods. Nares cultures were obtained from exposed healthcare workers (HCWs) to identify possible colonization by CNS with decreased susceptibility to vancomycin. RESULTS: The bloodstream infection by an S. epidermidis strain with decreased susceptibility to vancomycin occurred in a 49-year-old woman with carcinoma. She had two blood cultures positive for CNS; both isolates were S. epidermidis. Although susceptible to vancomycin by the disk-diffusion method (16-17 mm), the isolates were intermediate by MIC (8-6 microg/mL). The patient had received an extended course of vancomycin therapy; she died of her underlying disease. No HCW was colonized by CNS with decreased susceptibility to vancomycin. CONCLUSIONS: This is the first report in the United States of bloodstream infection due to S. epidermidis with decreased susceptibility to vancomycin. Contact precautions likely played a role in preventing nosocomial transmission of this strain, and disk-diffusion methods may be inadequate to detect CNS with decreased susceptibility to vancomycin.

Multidrug-resistant Enterococcus faecium. An untreatable nosocomial pathogen.

The prevalence of enterococci and nosocomial pathogens has increased over the past 15 years. They have become increasingly resistant to agents traditionally useful in the treatment of invasive diseases due to enterococci. Vancomycin resistance, first described in clinical isolates in 1988, has disseminated worldwide. It is usually associated with high-level resistance to penicillins and aminoglycosides rendering the treatment of patients with vancomycin-resistant enterococci very difficult. Several investigators have reported mortality rates greater than 50% for vancomycin-resistant enterococcal bacteraemia. Risk factors associated with vancomycin-resistant enterococcal bacteraemia include prolonged hospital stay, neutropenia, prior oral or parenteral vancomycin use, and broad spectrum antibiotics. Since there is no uniformly effective antimicrobial therapy for patients infected with vancomycin-resistant enterococci, preventing of the spread of infection with the rigorous application of barrier precautions and other infectious control techniques is of paramount importance.

Clostridium sordellii bacteremia: case report and review.

Clostridium sordellii is a gram-positive, anaerobic bacillus that has rarely been implicated as a human pathogen. It produces several exotoxins, which contribute to the progressive edema and refractory shock frequently seen with human infection. There have been eight prior reports of bacteremic C. sordellii infection and seven prior reports of nonbacteremic infections not due to myonecrosis of skeletal muscle. Mortality was 50% in the bacteremic group and 71% in the nonbacteremic group. Mortality correlated with both shock and leukemoid reaction at presentation. We present a case of C. sordellii sepsis in an asplenic patient with sickle beta thalassemia and inflammatory bowel disease, and we review the literature.