Minnesota Department of Health (MDH) Bug Bytes
December 11, 2001
Vol. 2: No. 20
1. Unexplained Deaths Following Knee Surgery
Last week's December 7 MMWR (http://www.cdc.gov/mmwr) provides an update on our investigation of three deaths following knee surgery at two separate hospitals in Minnesota. Since November 13, we, in collaboration with CDC, have investigated three patients who died unexpectedly following knee surgery. Following an initial investigation, on November 18, we made the unprecedented recommendation of suspending knee surgery for 7 days in the state pending further investigation. Patient 1 had received a knee osteochondral allograft, and patients 2 and 3 had undergone total knee replacement surgery. Extensive epidemiologic and microbiologic investigations have not linked the deaths of the three patients. Blood cultures from patient 1 prior to his death grew Clostridium sordellii. Blood cultures from patients 2 and 3 did not yield growth of any bacteria; molecular and special studies have not identified any Clostridium species in any antemortem or autopsy fluid/tissues from patients 2 and 3. The cause of death in these two patients remains unexplained.
As of December 10, neither surveillance in Minnesota by MDH nor enhanced case finding by CDC outside of Minnesota have identified any additional cases of C. sordellii infection associated with severe hemodynamic collapse or death in patients recently undergoing knee or other large joint surgery. Culture of non-implanted knee tissue from the same cadaveric donor source for Patient 1 has yielded growth of Clostridium species. During the past two and a half weeks, CDC has received other reports of allograft recipients infected with clostridial species and these cases are being investigated.
Clinicians should consider possible clostridial infection in patients with evidence of infection following allograft implantation. In some patients only local symptoms (knee pain) may be present during the early course of infection. There may be signs of sepsis, fever or hypothermia, hemodynamic compromise and/or abdominal pain. Anaerobic in addition to aerobic cultures should be obtained, and incubated for 7 days. If appropriate, other specimens (knee aspirate or tissue) should be obtained and Gram stain, aerobic and anaerobic cultures obtained. Clinicians should consider expanding empiric therapy to include anaerobic coverage. Consultation with an infectious disease physician is suggested. Cases of clostridial infection post-allograft should be reported to us at (612) 676-5414.
Last week's MMWR also had a report on four patients who developed polymicrobial post-surgical septic arthritis probably associated with contaminated allografts used for anterior cruciate reconstruction. These two reports highlight the need for standard practices for screening tissues for infection, oversight of tissue banks and improving methods to ensure the safety of these tissues.
2. Inhalational Anthrax Case in Connecticut
Last week's December 7 MMWR had an update on the investigation of a 94-year-old Connecticut (CT) resident who died from inhalational anthrax. The source of exposure for this patient remains unknown. Multiple environmental samples collected from all places the patient was known to have visited during the 60 days preceding illness onset were negative for B. anthracis by culture. Nasal swab specimens were negative from 16 persons epidemiologically linked to the case. The leading hypothesis is that she was exposed to her own mail that had been cross contaminated with anthrax from mail that had gone through a New Jersey post office which processed envelopes known to have contained anthrax spores. A similar case with no known direct exposure to B. anthracis had been reported from New York City.
In light of the large population exposed to mail potentially cross-contaminated with anthrax, and the absence of additional cases of inhalational anthrax, if there is a risk for inhalational anthrax associated with exposure to mail, it is very low.
As of December 5, a total of 22 cases of anthrax have been identified in the U.S.; 11 were confirmed as inhalational anthrax, and 11 (seven confirmed and four suspected) were cutaneous. We continue to receive and investigate suspect cases in Minnesota. Please call us immediately at (612) 676-5414 to report a suspect case or receive consultation.
3. Macrolide Resistance of
In the October 17 issue of JAMA (http://jama.ama-assn.org/issues/
v286n15/rfull/joc10626.html) is another article highlighting our work as part of the Emerging Infections Program network. Isolates of S. pneumoniae collected from 1995-99 from 8 EIP sites were tested for macrolide (erythromycin, clarithromycin, and azithromycin) resistance. Resistance increased from 10.6% to 20.4% over the time period. In order to maintain the therapeutic utility of macrolides, we must judiciously use them. Thank you ICPs and laboratories for all your contributions to these important findings!
4. Influenza is Here!
Influenza A has been identified in a 61 year-old male resident of Rochester. The specimen was collected at the Mayo Clinic and determined to be influenza A. Further subtyping was performed by us identified the strain as A/Panama-like (H3N2). The influenza vaccine for the 2001-2 influenza season contains the following strains: A/Moscow/10/99 (H3N2)-like, A/New Caledonia/20/99 (H1N1)-like, and B/Sichuan/379/99-like antigens. However, manufacturers have used the antigenically equivalent A/Panama/2007/99 (H3N2) virus in the vaccine. Therefore the specimen collected at Mayo is similar to the A/Panama (H3N2) strain used in this year's vaccine.
Historically, community-wide influenza is seen 6 to 10 weeks following the identification of the first isolate. Influenza vaccine is currently widely available across the state. So continue to promote influenza vaccine and don't forget that even if there is flu in the community, the flu shot can still be given!
Bug Bytes is a combined effort of the Infectious Disease Epidemiology, Prevention and Control Division and the Public Health Laboratory Division of MDH. We provide Bug Bytes as a way to say THANK YOU to the infection control professionals, laboratorians, local public health professionals, and health care providers who assist us.
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