Updates
May 1, 1999 4 minutes read
Updates
By Carol A. Kemper, MD
Trench Fever in the Homeless
Source: Brouqui P, et al. N Engl J Med 1999;340:184-180.
Trench fever, which we now know to be caused by Bartonella quintana, has classically been chracterized by relapsing fever, body aches, and headache. There is a growing body of evidence, however, that infection with B. quintana can cause relatively asymptomatic, chronic bacteremia, much the same as B. henselae can cause chronic bacteremia in apparently healthy cats. It is also rarely found to cause osteomyelitis and endocarditis, especially in individuals who live in poor socioeconomic conditions, are homeless, and/or chronic alcoholics.
Brouqui and colleagues, working with Didier Raoult in the Rickettsial Disease Unit in Marseilles, France, compared the results of blood cultures and serological studies in 71 homeless patients with those of 31 control subjects. All of the homeless subjects were negative for HIV. A total of 186 blood samples were obtained. Thirty-six blood cultures from 10 patients were positive for B. quintana, including five patients who had multiple positive cultures during periods of time ranging from two to six weeks. Only two of these 10 patients had evidence of fever, which had been attributed to the presence of tonsillitis in one and soft tissue infection in the other. A total of 21 (30%) patients had high titers of antibody to B. quintana, 17 (24%) of whom had evidence of current infection with positive blood cultures (n = 6), recent seroconversion (n = 7), or both (n = 4).
Homeless patients with bacteremia were significantly more likely to have headache, leg pain, and thrombocytopenia and were more likely to be infected with body lice than homeless patients without bacteremia or controls. Serologies for B. henselae were negative except in three patients with especially high antibody titers to B. quintana. There was no evidence of endocarditis in three patients who underwent echocardiography. Lice collected from three of five subjects with evidence of recent infection were positive for B. quintana by PCR, whereas none of the lice collected from 10 uninfected patients were positive.
Nearly one-fourth of homeless non-HIV-infected patients in southern France were found to be infected with B. quintana, although few had overt signs and symptoms of infection. Based on this information, it may be reasonable to assess the serological status of homeless subjects with body lice who present to the emergency room with headache or thrombocytopenia not attributable to other causes. Blood cultures could additionally be obtained at centers with that specialized capability, although because of the slow growth of the organism, the results are generally not available for two to seven weeks.
Resistance to HIV?
Source: Kaul R, et al. AIDS 1999;13: 23-29.
Some hiv-negative prostitutes in Kenya remain seronegative despite repeated exposure to HIV and are, therefore, considered "resistant" to HIV infection. The pathogenetic mechanisms contributing to this resistance may lie, in part, in a vigorous genital mucosal immune response. Kaul and colleagues demonstrated the presence of HIV-1 specific IgA antibody in the genital tracts of 16 of 21 (76%) female sex workers in Kenya at high risk for HIV infection, all of whom were HIV-seronegative. In contrast, HIV-1 specific IgA antibodies were found in the genital secretions of only five of 19 (26%) of their HIV-positive coworkers (P < 0.001), as well as three of 28 (11%) HIV-negative women at lower risk for HIV infection. All three in the latter group had some HIV risk factors on further questioning. IgG antibodies were not found in any of the HIV-negative sex workers but were identified in the genital secretions of all 19 HIV-positive women.
In addition, CD4+ T-cell lymphocyte responses to HIV-1 env antigens were detected in more than one-half of the HIV-negative women, but only 22% of the HIV-positive women. Apparent resistance to HIV-infection in female prostitutes with multiple risk exposure was highly associated with the presence of HIV-1 specific IgA antibody in genital secretions. This finding was independent of T-helper lymphocyte responses.
Preventing Surgical Wound Infection
Source: Vasseur PB, et al. Vet Surg 1998;17:60-64.
Vasseur and associates examined the risk factors for postoperative surgical wound infection for a total of 2063 procedures, including the experience of the surgical staff, the duration of the procedure, the cleanliness of the surgical wound, and whether the patient received perioperative antibiotics. As long as the procedures were quick (< 90 minutes), clean, and performed by an experienced surgeon (resident or faculty member), antimicrobial prophylaxis provided no benefit in reducing the frequency of wound infection. However, antibiotics did reduce the surgical wound infection rate when the procedures were performed by a senior student. Of course, since all of the patients were cats and dogs, this may not be too surprising. Overall infection rates for clean procedures were comparable to those seen in humans (2.5%), but were higher in clean-contaminated wounds (4.5%), contaminated wounds (5.8%), and in dirty wounds (18.1%). Interestingly, the postoperative rectal temperature was significantly associated with the duration of the procedure but was not predictive of subsequent wound infection.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content