Zhonghua Minguo wei sheng wu ji mian yi xue za zhi = Chinese journal of microbiology and immunology最新文献

Fecal specimens from 100 healthy adults were collected and examined for the presence of Bacillus cereus which has been associated with 28% of the outbreaks of food poisoning on Taiwan within the last 3 years. Total isolate rate from these specimens was 8%. Variations in isolation rates were found not only in sexes, but also in different age-groups. Therefore, presence of B. cereus in the feces of healthy adults may be unpredictable and relate to foods consumed or to other factors. Obviously, an isolation rate of B. cereus as high as 30% during the outbreak investigation is still not a strong evidence to implicate this organism as an etiological agent.

RapID onE System is a newly developed four-hour rapid diagnostic kit for the identification of enteric bacteria. To know the effectiveness of this system, we used 125 strains of oxidase-negative, gram-negative bacilli for this evaluation. Except for Acinetobacter calcoaceticus, all the bacilli belong to family Enterobacteriaceae. The bacterial strains of this assessment belong to 12 genera and 20 species. Among them, 84 strains were freshly isolated from clinical specimens and 41 strains were frozen (-70 degrees C) stock clinical isolates. The results show that 115 (92.0%) strains were correctly identifed to the species level. It yielded 92.9% and 90.2% of correct identification of fresh isolates and frozen stocks, respectively. In this paper, the reading criteria of RapID onE System would also be discussed.

The seroprevalence of human immunodeficiency virus (HIV) infection in Guinea-Bissau, West Africa, was determined by enzyme-linked immunosorbent assay (ELISA). From January 1987 to February 1993, 590 patients from the outpatient and inpatient departments of Regional Hospital at Canchungo, Cacheu, Guinea-Bissau were studied. The overall seropositive rate was 16%. Patients in the age between 25 and 54 accounted for 78% of HIV-positive cases. The seropositive rate according to the diagnosis was: 6% in pregnant women, 40% in patients with gonorrhea/syphilis, 14% in patients with vaginitis and 22% in patients with active pulmonary tuberculosis. The seropositivity for HIV-1/2 in the pregnant women might reflect the seroprevalence in general population of Guinea-Bissau. Accordingly, the estimated population infected by HIV would be sixty thousands in Guinea-Bissau. Both sexually-transmitted diseases and tuberculosis were the risk factors for HIV infection. This study shows that HIV infection is a critical problem of public health in Guinea-Bissau. Strategies to prevent the seeding of HIV are of great importance. Moreover, the members of medical mission from our country must keep alert for preventing HIV infection.

In order to enhance the immune response, people usually add adjuvant to the antigen in immunization. Freund's adjuvant is one of the most used. It can prolong the duration of the antigen staying in the body of the animal, and through continuous stimulation of the antigen the production of antibody is increased. This paper describes a few points in facilitating the emulsification of the antigen and making it more effective. The process can be summarized as follows: (1) Force a small amount of adjuvant from syringe B by pushing it into syringe A filled with antigen solution to mingle with the latter. (2) Push the same volume of the mix from syringe A back to syringe B slowly. (3) Repeat the above mixing process until the mixed portion has become milky white. (4) Gradually increase the volume by small amounts and each time do the same mixing until final completion. After immunization with the mixture, potent sera were always obtained. It has become a routine in this laboratory to use such mixture in its immunization tasks.

Twenty-one antimicrobial agents were incorporated individually into Frey's agar to evaluate their inhibitory activities against 86 isolates of avian mycoplasmas recently detected in Taiwan. Among them, 45 and 37 isolates were found positive with Mycoplasma gallisepticum and Mycoplasma synoviae fluorescent antibody conjugate, respectively. Twenty-one other isolates were unable to be identified by the above 2 conjugates. All of the field isolates were highly sensitive (with MIC50 < 1 microgram/ml) to enrofloxacin, gentamicin, myplabin, tiamutin and tylosin. However, those field isolates were highly resistant (with MIC50 > 32 micrograms/ml) to apramycin, chlortetracycline (CTC), erythromycin (ER), flumequine (FI), nalidixic acid (NA), oxolinic acid (OA), oxytetracycline (OTC) and spiramycin (SP). The inhibitory activities of the antibiotics which possessed an MIC90 of 50 micrograms/ml or less against local isolates were, in decreasing order, enrofloxacin (< 0.004 microgram/ml), gentamicin (1.53 micrograms/ml), tiamutin (1.81 micrograms/ml), tylosin (3.2 micrograms/ml), streptomycin (SM; 12.0 micrograms/ml), colistin (13.1 micrograms/ml), chloramphenicol (14.0 micrograms/ml), spectinomycin (15.0 micrograms/ml), myplabin (16.0 micrograms/ml), spiramycin (30.0 micrograms/ml), minocycline (32.0 micrograms/ml). The MIC90 of OA, CTC, SM, FI, SP, OTC, ER or NA was greater than 50 micrograms/ml; which work poorly in the control of mycoplasmoses. Since the antibiotic control policy is quite loose in Taiwan, many antimicrobial agents are often freely used in clinics, with a resulting gradual decrease in the inhibitory activity to the avian mycoplasmas.

Approximately 4000 nucleotides of the 5'-terminal portion of Japanese encephalitis virus (JEV) Ling strain genome were cloned and sequenced. This nucleotide sequence and its encoded C-PrM-E-NS1 polyprotein sequences were also compared with the corresponding sequences of other JE virus strains. Results demonstrated that the nucleotide sequence homology varied from 97.1 to 99.3% and the amino acid homology 98.6 to 98.9%. Based on homology, the Ling strain was closer to the Beijing-1 strain than to the SA14 and JaOArS982 strains. However, only on comparison of the E sequence, which neutralization, hemagglutination-inhibition and complement fixation antigenic determinants are located, between Ling and other JEV strains demonstrated that nucleotide sequence homology varied from 97.1% to 99.3% and amino acid homology from 98.6% to 99.2%. The Ling strain JEV is more closely related to the Beijing-1 strain than to the Nakayama NIH, SA14 and JaOArS982 strains in that order. Based on this analysis, the Taiwanese JEV strain appears to be more closely related to the Chinese strain than to the Japanese strain. Also, JEV strains isolated in humans are more closely related to each other than to JEV strains of mosquito isolates.

The purpose of this study was to use microbiological tests for diagnosis of periodontal diseases in Taiwan. Anaerobic culture, direct microscopy, indirect immunofluorescence (IF), and biochemical tests were used to examine 336 samples for the specific microorganisms in subgingival plaque. The results indicated that gram-negative species and motile bacteria were less frequently detected, and in lower proportion, in samples from healthy sites. The bacteria found frequently in healthy group were the coccal forms. However, Bacteroides forsythus detected by IF showed a close association with periodontal inflammation. Porphyromonas gingivalis was found with about 53% frequency in the periodontitis group; in more than half the samples the proportion was above 5%. Actinobacillus actinomycetemcomitans was recovered with 48% frequency of periodontitis group. Other cultivable species including Campylobacter rectus, Capnocytophaga species, Centipeda periodontii, Eikenella corrodens, Fusobacterium nucleatum, Prevotella intermedia, Selenomonas species, and the Spirochetes were detected in a significantly higher proportion in periodontitis group. The results strongly support the use of microbiological tests as adjuncts to diagnosis, and for assessment of the importance of microbiota in periodontal disease.

Reduced virulence for mice was characterized in an isolate (LV1) of a clone of the Tulahuén strain of Trypanosoma cruzi. LV1 caused long term chronic parasitemias which were measured for 140 days in both C3H/He and BALB/c mice inoculated with 1 x 10(5) trypanosomes/mouse. In contrast to the acute and rapidly lethal Tulahuén strain infections in both strains of mice, all of the animals survived the LV1 infections. Sera of C3H/He mice infected with the Tulahuén strain or LV1 isolate displayed similar titers in an enzyme-linked immunosorbent assay (ELISA) when reacted against homologous or heterologous extracts of epimastigote stages of the trypanosomes. Western blot reactions of the Tulahuén, Raccoon V, LV1 isolates, and the closely related European bat parasite, Trypanosoma dionisii defined shared antigens between the strains and species, while some appeared to be strain- and species-specific. The studies indicate a mutational event(s) resulted in reduced virulence and suggest that survival of the mice infected with T. cruzi is not correlated with high ELISA antibody titers. Since lower antibody titers are exhibited by mice infected with LV1 than mice infected with the Tulahuén strain, survival may be dependent on the specificities of the antibodies synthesized during the infections, cell mediated immune responses, and/or biochemical factors of the LV1 isolate which control virulence and differ from those of the original Tulahuén strain.

Human hepatitis B virus (HBV) infection has been closely linked to the occurrence of hepatocellular carcinoma (HCC). Hepatoma cell lines and nude mouse-passaged hepatoma tissues were used in this report to study the HBV DNA status in these cells after passage. DNA was extracted from seven hepatoma cell lines and three nude mouse passaged HCC lines. Southern blot hybridization technique was performed with either cloned HBV whole genome or subgenomic DNA fragments as probes to analyze the presence of HBV DNA. Integration of HBV DNA fragments was detected in one mouse passaged tissue, R. Hybridization with HBV subgenomic DNA revealed that there were some DNA rearrangements of the integrated HBV DNA in R. However, the integrated HBV DNA could not be detected in the cell line derived from R after in vitro cultivation for 2 years. Both episomal form and integrated HBV DNA were detected in a cell line NTU-h3. Episomal form HBV DNA ih NTU-h3 changed after several passages. HBV DNA in NTU-h3 was unstable after in vitro cultivation. Therefore, we concluded that the presence of HBV DNA might not be essential for the maintenance of the tumorigenicity of hepatoma and the nude mouse system was more stable for maintaining HBV DNA in HCC.