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

From 1977 to 1993, 15,189 throat swab samples were received for isolation and identification of influenza virus in the Clinical Virology Laboratory, Veterans General Hospital-Taipei. Most of the samples came from the Pediatric Department. There were 634 identified strains of the influenza virus; the successful isolation rate was 4.17% in average/year. Among these isolates, 56.3% (357/634) were influenza B; 12.1% (77/634) were influenza A/H1N1 and 28.1% (178/634) were influenza A/H3N2. About 3.5% (22/634) were classified as flu-like agents because of no reaction with available monoclonal antibodies. In recent years, reverse transcriptase polymerase chain reaction (RT-PCR) was established here to re-evaluate these virus stocks. This method can provide rapid diagnosis method to identify influenza A/H1N1, A/H3N2 and B. Further, the RT-PCR method and sequencing of amplified DNA could be used to see the variation of virus isolates which were recirculated or which reappeared in the Taipei area.

Hapten refers to a chemical compound of small molar mass (typically less than 1000 daltons) that can bind with an antibody, but cannot initiate an immune response by itself unless it is conjugated to a protein carrier of larger molar mass. A novel method to prepare a hapten to generate anti-hapten immunity without covalent conjugation to a carrier was developed. Coating both water-soluble and -insoluble haptens onto a nitrocellulose membrane effectively presented haptens to the system and caused the generation of specific anti-hapten B lymphocytes and antibodies by immunization both in vitro and in vivo. This method has a potential to substitute for conventional hapten carrier conjugation to generate anti-hapten immunity.

Aedes albopictus is a dominant mosquito species in northern Taiwan. In laboratory, the vector competence of 2 geographical strains of Aedes albopictus mosquitoes to NT 113 strain of Japanese encephalitis virus was examined. The mosquito infection dose50 (MI-D50) of Sanhsia (SH) strain by intrathoracic (i.t.) inoculation was shown to be -1.1 log WMICLD50 (weanling mice intracerebrum lethal dose), while that of Yungho (YH) strain was -2.0 log WMICLD50. The infection dose for 50% mosquitoes transmission (MTID50) by i.t. inoculation was 3.5 log with SH strain but no transmission occurred with YH strain. By feeding sweetened blood-virus mixture, the MID50 with SH strain was 2.7 log though YH strain did not attain 50% infection rate. By viremic mouse blood feeding, the highest infection rate for both strains was about 30%. No evidence of virus transmission was demonstrated by oral infection.

A total of 129 strains of Staphylococcus aureus, isolated from clinical specimens in Taiwan between February 1992 and December 1993, were subjected to coagulase typing and susceptibility testing to 21 kinds of antimicrobial agents using Pasco MIC Gram-positive panels. In the determination of minimum inhibition concentration (MIC), there were 94 strains (72.9%) resistant to penicillin and ampicillin, 54 strains (41.9%) resistant to tetracycline and erythromycin, and 21 strains (16.3%) resistant to oxacillin (oxacillin-resistant S. aureus; ORSA), but none of them was resistant to vancomycin or nitrofurantoin. As the susceptibility of the isolates from four different geographic districts was compared, no statistical difference was found except that the resistance rate to penicillin and ampicillin was higher in southern Taiwan, and resistance rate to rifampin and gentamicin was higher in central Taiwan. The ORSA strains were all resistant to penicillin, ampicillin, tetracycline; 95.2% of the strains were resistant to gentamicin, tobramycin and erythromycin. The resistance rates to drugs tested for ORSA strains were statistically higher than those for OSSA strains except vancomycin, nitrofurantoin, trimethoprim/sulfamethoxazole and ampicillin/sulbactam. In the coagulase typing of 127 strains, Type IV, III and VII were most frequently encountered. Among the coagulase types, Type IV was mostly encountered in the North, the South and the East of Taiwan; Type III was mostly encountered in central Taiwan. Among the ORSA strains, coagulase Type III was most predominant (85%). In conclusion, analysis of an antibiogram is easy to perform and the results can provide clinicians not only with correct guides for patient treatment but also with a useful tool for epidemiological studies. However, if antibiogram and coagulase typing are carried out simultaneously, results will be more reliable in epidemiological studies, including nosocomial infection survey.

A synthetic 17 mer oligonucleotide (5'-GTTGGGTAACGCCAGGG-3') was used as a primer for the arbitrarily primed polymerase chain reaction (AP-PCR) to differentiate various strains of Vibrio vulnificus. A total of 37 genomic DNAs that were extracted from the clinical and environmental strains were successfully differentiated. Among them, 32 profiles of the 37 strains were characterized. None of the environmental and clinical strains had the same amplification profile, suggesting the highly heterogeneous population existed in the strains of V. vulnificus. The size of the amplified sequences ranged from 0.3 to 2.0 Kb and the DNAs were separated to 12 to 20 bands by the 1.2% agarose gel. The clinical isolates from two independent episodes of V. vulnificus infections in a patient were shown to have the same profile, indicating that the second episode was due to recurrence rather than reinfection. The profiles of amplification were reproducible with different preparations of genomic DNA. Arbitrarily primed polymerase chain reaction can therefore be a useful tool for epidemiological study of V. vulnificus infection.

Streptococcus mutants constitutively expresses three glucosyltransferases (GTFs), i.e., GtfB, GtfC, and GtfD, which synthesize glucan polymers from sucrose. Two genetically constructed mutants of S. mutans which stably expressed either the cell-associated or the extracellular GTFs were selected for purification and characterization of these enzymes. The cell-associated GtfB and GtfC from strain GS-5DD lacking the gtfD gene expression were extracted by urea, renatured by dialysis in sodium phosphate buffer and then separated from the other wall-associated components by column chromatography. The extracellular GtfD was purified from the culture supernatant of strain NHS1 lacking gtfB and gtfC gene expression. The molecular weights of the purified GTFs was similar (150-160 kDa), as determined by SDS-polyacrylamide gel electrophoresis. The GtfB/C preparation synthesized primarily water-insoluble glucan in a primer independent manner. However, the presence of the dextran enhanced the enzymatic activities of the GtfB/C. GtfD synthesized water-soluble glucan exclusively in a primer dependent manner. Purified GtfD had a pH optimum of 5.5, and a K(m) value of 4.35 mM for sucrose. These results indicated that the mutated strains served as an efficient and specific host to obtain native GTFs.

The minimal concentration of adenosine triphosphate (ATP) which could be detected with spectrophotometry, HPLC and luciferin-luciferase methods was 1.0 microM, 3.3 microM and 100 nM, respectively. In submerged cultivation, most Streptomyces rimosus TM-55 was in hyphae fragment form at 65 h, became short-rod mycelia at 166 h, and lysed at 504 h incubation. The ATP content had maximal value at 24 h, then gradually decreased during cultivation. The oxytetracycline potency increased as incubation occurred, had maximal potency 178.9 micrograms/ml at 166 h, and then gradually decreased. Morphogenesis was very important in oxytetracycline production in submerged cultivation of Streptomyces; short-rod mycelia had high oxytetracycline production.

An immunization program against diphtheria has been implemented in Taiwan since 1955, using combined diphtheria, pertussis and tetanus (DPT) vaccine. Diphtheria immunoglobulin (DIG) level was assessed in serum samples obtained from 1138 children, aged 3-6 years from north, south, east and central part of Taiwan by the VERO cell neutralization method. Specimens were collected by simple random sampling of residents from Hsinchu, Taichung, Pingtung and Hwalien counties, including both aborigines and non-aborigines. The former lived in one or two villages in each county, and the latter lived in a single village next to the former. Ninety-five percent (1086/1138) had a DIG titre > or = 0.01 IU/ml. There was no significant difference by sex, or by residential area. Seventy-nine percent (901/1138) of the children had completed the primary immunization schedule (at the age of 2, 4, 6 and 18 months), and the prevalence of DIG titre > or = 0.1 IU/ml considered to be long-term protective was as follows: 74.6% for 3-year group; 74.5% for 4-year group; 67.9% for 5-year group; 84.7% for 6-year group (including 52.2% who had had a booster shot at early primary school). These findings show that the diphtheria vaccination program provides good immunity in childhood.

The large number of hemocytes infiltrated several abnormal tissues of kuruma shrimp (Penaeus japonicus), including musculature, hepatopancreas, lymphoid organ, gill filament and sponge tissue. In addition, there were many denatured hemocytes existing inside acidophilic particles and forming granules. Futhermore, in hepatopancreas of kuruma shrimp, a white spot baculovirus (WSBV; 40-50 x 50-300 nm) was discovered in UH (undifferential haemocyte). The epithelium cells, which including stomach cuticle and underlying epidermis of exoskeletal cuticle, could also be infected by WSBV in another main cultural species--grass shrimp (P. monodon). During a period of high water temperature, with pond shrimp in normal condition, the CFU/ml of water bacteria rose from 10(5) to 10(7), but this number had decreased to 10(5) CFU/ml by the time moribund shrimp began to appear. Coincidentally, the total bacterial number isolated from hepatopancreas and musculature of moribound shrimp was over 10(5) (CFU/g) and 10(3)-10(5), respectively. The fauna of bacteria was taken over by the active metabolitic species which were represented by Vibrio species causing the pond shrimp to undergo either behavioral changes, such as swimming on the water surface, or histological changes, such as having whitish muscle color, hemocyte infiltration and granuloma formation etc. Pathogenetic species of Vibrio including V. parahaemolyticus, V. alginoly ticus V. anguillarum, V. fischery and V. damsela were isolated from those tissues of moribund shrimp. The main pathogens, isolated from musculature and hepatopancreas, were V. parahaemolyticus and V. alginolyticus. On the other hand there, was no bacterium could be isolated from the musculature of healthy shrimp and only a single species of Gram (+) coccus--Micrococcus--was isolated from the tissue of hepatopancreas.