16S rDNA PCR in diagnosis of Lemierre's syndrome

In their Grand Round paper, Krutika Kuppalli and colleagues have omitted an important device for the diagnosis of Lemierre’s syndrome. Molecular methods, including broad-range 16S rDNA PCR, are increasingly being used 1 Amoroso A, Etienne-Mesubi M, Edozien A, Mesubi OO, Guberski T. HIV-1 drug resistance in antiretroviral-naive patients in sub-Saharan Africa. Lancet Infect Dis 2012; 12: 585–86. 2 Hamers RL, Wallis CL, Kityo C, et al. HIV-1 drug resistance in antiretroviral-naive individuals in sub-Saharan Africa after rollout of antiretroviral therapy: a multicentre observational study. Lancet Infect Dis 2011; 11: 750–59. 3 Bennett DE, Jordan MR, Bertagnolio S, et al. HIV drug resistance early warning indicators in cohorts of individuals starting antiretroviral therapy between 2004 and 2009: World Health Organization global report from 50 countries. Clin Infect Dis 2012; 54 (suppl 4): 280–89. 4 Gupta RK, Sultan BJ, Hill A, et al. Global trends in antiretroviral resistance in untreated HIV-1 infected individuals following ART roll-out in resource-limited settings: a global collaborative study and meta-regression analysis. Lancet 2012; 380: 1250–58. 5 WHO. WHO HIV drug resistance report 2012. http://www.who.int/hiv/pub/drugresistance/ report2012/en/index.html (accessed Sept 10, 2012) 6 Hamers RL, Kityo C, Lange JM, de Wit TF, Mugyenyi P. Global threat from drug resistant HIV in sub-Saharan Africa. BMJ 2012; 344: e4159. on culture-negative specimens from normally sterile sites in developed countries. The authors acknowledge that a high index of clinical suspicion is key to the diagnosis of Lemierre’s syndrome. However, in my experience, the diagnosis is almost always delayed, either due to atypical presentation (ie, many suppurative lesions in the absence of a history of upper respiratory tract illness) or because the causative organism(s) cannot be recovered as a result of their fastidious nature or previous antibiotic treatment. 16S rDNA PCR has two major advantages in the management of patients presenting with a febrile illness and suppurative lesions, especially those who have received previous antibiotic treatment. First, the method encompasses several genera of bacteria, enabling diagnosis of other bacterial infections presenting with similar clinical features, such as Staphylococcus aureus, group A streptococci, and Streptococcus pneumoniae. Second, because the test detects molecular material from bacteria, previous antibiotic treatment would not inter fere with the diagnosis, as is the case with conventional culture methods. Molecular methods can also be used on throat swab for the diagnosis of Lemierre’s syndrome, but results should be interpreted with caution. As is the case with any other laboratory tests, molecular methods do have limitations regarding their sensitivity and specifi city. Nevertheless, 16S rDNA PCR has been shown to increase diagnostic yield. Although not perfect, if available, molecular methods should be used alongside routine culture methods in cases with a high probability of the illness being Lemierre’s syndrome.