ICAAC/IDSA/ASTMH 2003 Conferece Coverage

The following is a summary of selected abstracts from 3 meetings. The 43rd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) met in Chicago September 14-17, 2003. The Infectious Disease Society of America (IDSA) met in San Diego October 9-12, 2003. The American Society of Tropical Medicine and Hygiene met in Philadelphia December 3-7, 2003.—Stan Deresinski, MD, FACP

Blood- and Tissue-Dwelling Protozoa

Trypanosomiasis

Forty-four HIV-infected patients were found to be coinfected with Trypanosoma cruzi at one Sao Paulo clinic. During follow-up, 46% developed manifestations of the parasitic infection, including 4 with reactivation acute myocarditis, 3 with meningoencephalitis, and 1 with skin lesions. Two additional subjects who remained asymptomatic had organisms detected on direct microscopic examination of blood. Others developed progressive cardiomyopathy or megaesophagus (ASTMH 778).

Bushmeat

The African bushmeat trade is believed to have played a critical role in the introduction of HIV infection into humans from primates. It has also been identified as important in outbreaks of Ebola virus infection in humans. A survey of bushmeat markets in 8 major urbanized areas throughout Liberia found that the most preferred species were cane rat, water chevrotain, giant pangolin, black duiker, brush-tailed porcupine, bush buck, and giant forest hog (ASTMH 547).

Cestodes

Echinococcus

Three patients with progressive human alveolar echinococcosis had responses to ongoing treatment with IV amphotericin B (ASTMH 389).

Intestinal Parasites

Cyclospora cayetanensis infections were common but usually asymptomatic among residents of San Carlos Island, Venezuela (ASTMH 337).

Examination of blended fruit drinks collected from street vendors and small restaurants in Mexico detected Trichuris trichiura ova in 13 of 27. E histolytica cysts were found in 7 samples, Ascaris lumbricoides ova in 4, and G lamblia cysts in 1 (ASTMH 494).

Trematodes

Liver Flukes

Seventeen cases of opisthorchiasis or clonorchiasis were diagnosed by stool examination in immigrants in St. Paul over a 6-year period. Half of the cases were identified at initial refugee screening, while the remainder were not detected until as long as 14 years after arrival in the United States. While the majority of patients came from Southeast Asia, more recent cases have occurred in individuals from the former Soviet Union and 1 from Latin America. Eosinophilia was present in 88% but was often mild (ASTMH 151).

Schistosomiasis

Among individuals tested by the US State Department over a 5-year period, 70 (60%) had serological evidence by immunoblotting of infection with Schistosoma mansoni, 4 (3.4%) with S haematobium, 1 (1.1%) with S japonicum, and 17 (15%) were reactive to both S mansoni and S haematobium. Most of these infections were acquired in Africa; the individual with S japonicum seropositivity had been in the Philippines (ASTMH 700).

Viral Infections

Muructu Fever

Muructu virus is a group C virus of the family Bunyaviridae. Eight patients with muructu fever were identified in Iquitos, Peru, in the Amazonian region. The patients were aged 16-45, and all presented with fever, chills, and arthralgia. Most had headache and ocular pain. All markedly improved or completely recovered within 14 days of onset (ASTMH 141).

Yellow Fever

Ribavirin administration beginning 24-48 hours after exposure was therapeutically effective in a hamster model of yellow fever virus infection (ASTMH 364).

Miscellaneous

In a randomized trial, a 5-day course of amoxicillin/clavulanate 2000 mg/125 mg b.i.d. was superior to placebo in reducing episodes of infection after third mandibular molar removal (ICAAC L-1384).

In a randomized, blinded, placebo-controlled trial, the administration of doxycycline and rifampin for 3 months to patients with Alzheimer’s disease was associated with significant reduction in decline in cognitive function. Serological and PCR studies suggest that the benefit was not related to any effect on C pneumoniae (IDSA 516).

Infliximab administration to 7 children with Kawasaki syndrome refractory to IVIG plus aspirin and/or cortico-steroids was associated with resolution of fever within 24 hours, as well as marked clinical improvement and normalization of C-reactive protein levels (IDSA 803).

C-reactive protein was elevated 4-fold or more in 15 of 15 children with classical PFAPA syndrome (periodic fever with lymphadenopathy, pharyngitis, and aphthous stomatitis). The erythrocyte sedimentation rate was > 40 mm/h in only 1 of 11 tested (IDSA 897).

Smallpox vaccination was associated with an increase in C-reactive protein (IDSA 815).

Investigators demonstrated silencing of antibiotic resistance genes in vivo in the absence of antibiotic administration. Thus, expression of mRNA was switched off, despite the presence of apparently intact promoters and resistance genes (ICAAC C1-174a).

An outbreak of staphylococcal scalded skin syndrome affected 13 neonates (ICAAC K-1439).

S pneumoniae was a rare cause of bacteremia in adults with sickle cell disease in France (ICAAC L-119).

Preterm infants immunized with DTPa-HBV-IPV/Hib at the chronological ages of 2, 4, 6, and 18-20 months developed antibody responses similar to that observed in full-term infants (ICAAC L-186a).

A retrospective cohort study found that the use of vancomycin was significantly associated with the subsequent isolation of ciprofloxacin-resistant Klebsiella spp. (ICAAC K-697).

A single 40-mg dose of atorvastatin significantly inhibited neutrophil chemotaxis in healthy volunteers without affecting serum lipid concentrations (ICAAC N-1518).

Stan Deresinski, MD, FACP, Clinical Professor of Medicine, Stanford; Associate Chief of Infectious Diseases, Santa Clara Valley Medical Center, and Editor for Infectious Disease Alert.