Evaluation of direct immunofluorescence test for diagnosis of upper respiratory tract infection by Chlamydia pneumoniae.

BACKGROUND: Chlamydia pneumoniae causes a variety of respiratory infections and is involved in cardiovascular diseases. Diagnosis of C. pneumoniae infection currently relies on antibody detection by microimmunofluorescence (MIF), which has limited use, and is the retrospective diagnosis for acute infection. OBJECTIVE: Find an effective early diagnosis of acute upper respiratory infection, or use in combination with MIF to accurately diagnose the infection by C. pneumoniae. MATERIAL AND METHOD: Direct immunofluorescence (DIF) was developed to detect C. pneumoniae in nasopharyngeal specimens obtained from patients with upper respiratory tract infection, and normal individuals. IgM and IgG antibodies against C. pneumoniae by MIF were determined for evaluation of the detected C. pneumoniae and seroconversion. RESULTS: DIF gave positive results in 29 of 37 (78.4%) samples from 31 patients. Fifteen samples positive by DIF illustrated antibody titers interpreted as acute C. pneumoniae infection, and eight DIF positive samples showed antibody titers of chronic infection. Negative results by both DIF and MIF were found in two patients and 23 of 25 by DIF but 20 of 25 by MIF in normal subjects. Five paired sera subsequently collected from three of the 31 patients illustrated seroconversion 2-4 months after the primary specimen collection, which gave positive results by DIF but negative for antibodies. Significant association was found between C. pneumoniae detection by DIF and antibodies by MIF when analysis was done in the group of patients and normal subjects (p < 0.001; Pearson chi-square test). CONCLUSION: DIF could be an alternative assay for early diagnosis of C. pneumoniae infection, and may be used in combination with MIF for accurate diagnosis of acute C. pneumoniae infection.

Leptospirosis in Takeo Province, Kingdom of Cambodia, 2003.

BACKGROUND: In Cambodia, epidemiology and disease burden of leptospirosis were not addressed as they do not have an existing surveillance system and have limitations on their laboratory diagnosis. OBJECTIVE: Define the existence of leptospirosis and determine the antibodies to serovars of leptospires in Cambodia. MATERIAL AND METHOD: One hundred and twenty-one suspected cases of leptospirosis were enrolled in this cross-sectional study, between September 8 and November 30, 2003 from Takeo Provincial Hospital in Doun Keo District, Cambodia. RESULTS: Common clinical manifestations were fever (96%), headache (92%), and myalgia (87%). Common risk behaviors were throwing garbage on the ground (84%), pulling out sprouts (77%), fertilizing (49%), and plowing (47%). Microscopic agglutination test result confirmed four cases and polymerase chain reaction test result confirmed seven cases. Two cases each showed antibodies to serovars Javanica and Australis. An estimated annual incidence of leptospirosis in Takeo province was 7.65 per 100,000 populations. Further studies to define epidemiology and burden of disease are needed. CONCLUSION: Increasing awareness and knowledge on leptospirosis among people are necessary to decrease the impact of leptospirosis in Cambodia.

Mycobacterium avium and Burkholderia pseudomallei (Melioidosis) coinfection in an HIV-positive patient.

A 29 year old HIV positive Thai female with CD4 count of 10 cells/mm3 presented with chronic diffuse abdominal pain, fever, weight loss, anemia and leucopenia. Ultrasonography demonstrated diffuse upper abdominal lymphadenopathy with ascites. Microbiological and molecular work up of the specimen obtained by ultrasound-guided lymph node aspiration revealed co-infection with Burkholderia pseudomallei and Mycobacterium avium. Indirect hemagglutination, IgM-indirect fluorescent antibody, and IgG-indirect fluorescent antibody to Burkholderia pseudomallei were < 1:20, < 1:50 and < 1:50, respectively, at nine months, four months before the culture diagnosis and two months, eight months after the culture diagnosis of Burkholderia pseudomallei infection. The patient was treated initially with two weeks of intravenous ceftazidime, followed by oral cotrimoxazole, doxycycline and chloramphenicol. Clarithromycin and ofloxacin were added after the identification of Mycobacterium avium and its susceptibility test. The patients demonstrated clinical improvement with decreasing abdominal pain and resolution of fever.