Successful Treatment with Caspofungin of Hepatosplenic Candidiasis Resistant to Liposomal Amphotericin B

Sir—In their study of the community prevalence of carriage of methicillin-resistant Staphylococcus aureus (MRSA) among San Francisco’s urban poor, Charlebois et al. [1] found an overall prevalence of MRSA carriage of 2.8%. Injection drug use and prior hospitalization within 1 year were significant multivariate risk factors for MRSA acquisition. During the spring of 2000, a similar point prevalence study of MRSA nasal carriage among injection drug users (IDUs) in the downtown east side of Vancouver, British Columbia, was conducted jointly by the Communicable Disease Control Division of the Vancouver/Richmond Health Board and the Division of Medical Microbiology and Infection Control, Vancouver Hospital and Health Sciences Centre (VHHSC). Vancouver has a large concentration of economically disadvantaged individuals in the downtown east side of the city core. This inner-city neighborhood is home to 47,940 people, 52% of whom live below the poverty level. The life expectancy for men is 65.8 years, compared with 79.9 years in Vancouver’s wealthiest neighborhood [2]. The area provides services for 12,000 IDUs, many of whom live in the area’s ∼500 single-room–occupancy hotels [3]. Approximately 3,000,000 needles are dispensed annually through the needle-exchange program [4]. Nasal specimens were obtained from 299 IDUs, by teams of 2 nurses working on the streets who recruited participants from those requesting needle exchange. Information was collected on sex, age, and history of hospitalization for 148 h in the previous 3 months. Participants took their own nasal specimens under the supervision of the nurses. Specimens were taken that same day to the VHHSC microbiology laboratory and subcultured to blood agar plates. Colonies of S. aureus were screened for MRSA by use of 6 mg oxacillin screening agar, and colonies suspected to be MRSA positive were confirmed and typed by PCR [5]. Eighty-one (27%) of the samples, from 191 (64%) men and 107 (36%) women (the sex of 1 participant was not recorded), grew S. aureus. MRSA was identified in 22 (27%) of these isolates, and all were identified as serotype 21 by PCR. Overall, the MRSA carriage rate was 7.4% of the population surveyed and was similar for men and women. Only 18% of the MRSA-positive subjects reported having been hospitalized within the previous 3 months, compared with 15% whose samples grew methicillin-sensitive S. aureus and 21% who were negative for S. aureus or MRSA. Although the rates of colonization with S. aureus and with MRSA (in those identified as IDUs) were similar to those found by Charlebois et al. [1], our study differed with respect to the detection of only 1 predominant MRSA type and the lack of association between hospitalization and MRSA colonization. Our data suggested that clonal spread unrelated to hospitalization was occurring within the IDU population in the downtown area. This is further supported by the fact that serotype 21, as determined by PCR, comprises only 42% of strains found in the hospital serving the downtown east side. This study raises important questions regarding screening of IDUs for antibiotic resistant organisms prior to admission to a hospital, the use of antibiotics for outpatients (all the MRSA strains were resistant to multiple antibiotics), and empiric therapy for serious infections in this patient population. The identification of a single clone in this community raises the possibility of spread among the urban poor and eventually a higher community prevalence.