UPDATE IN INFECTIOUS DISEASES
[Mandell GL Ann Intern Med 2001;135:897]:
This is the annual review from the Annual College of Physicians 2001 annual session as published in the Annals of Internal Medicine. The reviewer for publications in 2000 was Gerald Mandell from the University of Virginia. Our summary will be brief since nearly all of the papers have been previously cited in these columns.
Zeuzem S, Feinman SV, Rasenack J, et al. Peginterferon alfa-2a in patients with chronic hepatitis C. (NEJM 2000;343:1666–72): The authors report the benefit of Peginterferon compared to standard interferon in a trial with 531 patients with chronic hepatitis C. Peginterferon proved superior, presumably because of its longer half-life, which also provided the advantage of once weekly administration instead of thrice weekly. It should be noted that monotherapy with interferon for hepatitis C is now antiquated and the preferred treatment is peginterferon plus ribavirin.
Whitney CG, Farley MM, Hadler J, et al. Increasing prevalence of multidrug-resistant Streptococcus pneumoniae in the United States. (NEJM 2000;343:1917–24): This report is from the Active Bacterial Core Surveillance Program of the CDC concerning 3475 patients with invasive S. pneumoniae infections generally meaning bacteremia or meningitis. The results showed 24% were relatively resistant to penicillin including 14% resistant at 2 mcg/ml. Analysis of sequentially collected isolates from 1995–1998 showed the frequency of resistance to three or more antimicrobial classes increased from 9% to 14%. The relevance of these observations was shown in a review of 6000 cases of communityacquired pneumococcal pneumonia where the overall mortality rate was 12% and the odds ratio for death with penicillin-resistant strains compared to penicillin-sensitive strains was 7 (Am J Public Health 2000;90:223).
Turner RB, Cetnarowski WE. Effect of treatment with zinc gluconate or zinc acetate on experimental and natural colds. (Clin Infect Dis 2000;31:1202–8): This is yet another report of zinc therapy for the common cold, but it is larger than most of its predecessors. There were two groups of patients including 281 with natural colds and 273 with colds induced by rhinovirus type 3. The authors concluded that zinc compounds, either zinc gluconate or zinc acetate, had no substantial benefit for the common cold.
Tsaparas YF, Brigden ML, Mathias R, et al. Proportion positive for Epstein-Barr virus, cytomegalovirus, human herpesvirus 6, Toxoplasma, and human immunodeficiency virus types 1 and 2 in heterophile-negative patients with an absolute lymphocytosis or an instrument-generated atypical lymphocyte flag. (Arch Pathol Lab Med. 2000;124:1324–30): The authors prospectively examined 70 heterophile antibody-negative patients with an absolute lymphocytosis or atypical lymphocytes with clinical symptoms compatible with mononucleosis. Infection with Epstein-Barr virus was identified in 40%, cytomegalovirus in 39%, HHV6 in 25% and Toxoplasma in 3%. There were no cases of HIV infection. The authors concluded that EBV and CMV are the major causes of mono-spot negative mononucleosis.
Brooks I, Gooch WM, Jenkins SG, et al. Medical management of acute bacterial sinusitis (Ann Otol Rhin Laryngol Suppl 2000;182:2). Recommendations from this group were amoxicillin and TMP-SMX, but the amoxicillin dose should be higher than customary at 80–90 mg/kg/day. Second line agents should be cephalosporins, clarithromycin, azithromycin or a newer fluoroquinolone. Antibiotics were recommended if there were >7–10 days of symptoms unless the patient is febrile or has significant face pain. Symptoms should resolve in 10–14 days.
Hayden FG, Gubareva LV, Monto AS, et al. Inhaled zanamivir for the prevention of influenza in families. Zanamivir Family Study Group. (NEJM 2000;343:1282–9): The authors performed a double blind, placebo-controlled trial of inhaled zanamivir to determine the probability of infection in healthy household contacts. This was 19% in the placebo group and 4% in contacts of zanamivir recipients, a 79% reduction. The reviewer points out that it is not clear that neuraminidase inhibitors have an impact on life-threatening complications of influenza and it is not known that they are more effective when combined with rimantadine or amantadine.
Unusual infections and modes of transmission
Human rabies–California, Georgia, Minnesota, New York and Wisconsin, 2000. (JAMA 2001;285:158–60); Human rabies–Quebec, Canada, 2000 (MMWR 2000;49: 1115–6): This is a report from the CDC of 5 cases of human rabies in the US in 2000. Four were caused by exposure to bats and one was a patient bitten by a puppy from Africa. All patients died 5–17 days after the bite. Many of the patients had no clear bat injury so that post-exposure prophylaxis is considered indicated after contact with the bat unless there is certainty that there was no bite or mucosal exposure. This includes consideration of prophylaxis for anyone who has been in the same room with the bat and is even unaware of any direct contact.
Enserink M. Infectious disease. The enigma of West Nile (Science. 2000;290:1482–4): West Nile virus because endemic in the US with the initial observation of cases in 1999 when there were 62 cases including 7 that were lethal. Nearly all the cases in 1999 were in the New York City area, but the next season the WNV cases were identified in 11 East Coast states and Washington, DC. Encephalitis is relatively rare and found in only 1–2% of cases, primarily elderly persons. Ribavirin is active in vitro, but there are no clinical studies as yet.
Becker KM, Moe CL, Southwick KL, et al. Transmission of Norwalk virus during football game (NEJM 2000;343:1223–7): This is the report of the epidemic of Norwalk virus infection in the Duke University football team where players became sick 10–50 hours after eating a box lunch the day before their game with Florida State University. The attack rate for those who ate the box lunch was 62% and the infection was traced to turkey sandwiches. Infected players had stained uniforms from vomiting and diarrhea during the game, and secondary cases occurred in 11 players for Florida State. The author notes that Norwalk agent accounts for 96% of outbreaks of acute nonbacterial gastroenteritis.
Ruiz GM, Rawlings TK, Dobbs FC, et al. Global spread of microorganisms by ships (Nature 2000;408:49–50): Commercial ships fill ballast tanks with sea water to gain stability and then dump the water when picking up cargo. This report concerns the detection of Vibrio cholerae 01 and 0139 in ballast water in ships arriving at the Chesapeake Bay. This is the mechanism of transmission implicated in the Asian outbreak of cholera that was subsequently transferred to other sites such as South America.
Brown P, Rau EH, Johnson BK, et al. New studies on the heat resistance of hamster-adapted scrapie agent: threshold survival after ashing at 600° C suggests an inorganic template of replication (Proc Natl Acad Sci USA 2000;97:3418–21): This report showed a hamster-adapted scrapie agent remained infectious despite conversion to ash by 600° C (but not 1000° C). The practical application of this information is that cooking meat will not get rid of prions.
McNeil SA, Clark NM, Chandrasekar PH, et al. Successful treatment of vancomycin-resistant Enterococcus faecium bacteremia with linezolid after failure of treatment with Synercid (quinupristin/dalfopristin). (Clin Infect Dis 2000;30:403–4): The authors review the utility of quinupristin/dalfopristin for the treatment of bacteremia due to E. faecium. The drug (Synercid) has been FDA approved for infections of skin and soft tissue caused by E. faecium, methicillin-susceptible S. aureus and S. pyogenes. It must be given intravenously by central line to avoid phlebitis and side effects include myalgia, joint inflammation and elevated bilirubin levels. The reviewer points out that an alternative is linezolid, which is active against nearly all gram-positive cocci, is well absorbed with oral administration and usually well tolerated. Problems with linezolid are the high cost and the possibility of bone marrow suppression.
Wingard JR, White MH, Anaissie E, et al. A randomized, double-blind comparative trial evaluating the safety of liposomal amphotericin B versus amphotericin B lipid complex in the empirical treatment of febrile neutropenia. L Amph/ABLC Collaborative Study Group. (Clin. Infect Dis. 2000;31:1155–63): The authors performed a double-blind trial with 224 neutropenic patients who remained febrile after 3 days of antibacterial treatment. Formulations of amphotericin were ABLC and liposomal amphotericin. The liposomal formulation was better tolerated in terms of febrile reactions (20% vs. 58%), chills (24% vs. 80%), and nephrotoxocity (15% vs. 42%). The reviewer points out the ethical dilemma confronting clinicians who must choose between preparations that are less toxic, but more expensive.
Kaul R, McGeer A, Norrby-Teglund A, et al. Intravenous immunoglobulin therapy for streptococcal toxic shock syndrome—a comparative observational study. The Canadian Streptococcal Study Group (Clin Infect Dis. 1999;28:800–7): The authors compared outcome of streptococcal toxic shock syndrome in 21 consecutive patients treated with IVIG vs. 32 historic controls. The regimen was 2 gm/kg times once or repeated at 48 hours if the patient was still unstable. The 30-day survival rate was nearly double with IVIG: 57% vs. 34%. The reviewer recommends management of this disease with penicillin, clindamycin, and IVIG.