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

Surveillance system of nosocomial infection was established in 1980 at the National Taiwan University Hospital (NTUH). To identify pathogens and the secular trends in the etiology of nosocomial infection from 1981 to 1994, the prospective, hospital-wide nosocomial surveillance data were analysed. During this period, 22,146 pathogens causing nosocomial infections were isolated. Gram-negative aerobic bacteria remained the major pathogens, but gram-positive cocci and fungi increased rapidly in the past 14 years. When the overall pathogen distribution is examined, Pseudomonas areuginosa was the most frequently isolated pathogen, but Candida albicans and other yeasts have taken the leading position since 1993. Staphylococcus aureus and coagulase-negative staphylococci also increase significantly in recent years. When the pathogens causing infection at the 4 major sites were examined. P. aeruginosa was the pathogen most often associated with respiratory tract and surgical wound infections. In blood stream and urinary tract infections, we observed Escherichia coli was replaced by C. albicans and other yeasts as a most common isolate in these years. In addition, C. albicans and other yeasts and methicillin-resistant S. aureus (MRSA) are emerging as major nosocomial pathogens at NTUH. C. albicans and other yeast increased from 1.8% in 1981 to 14.9% in 1994 in the overall nosocomial infection. The increase was found in the blood stream (2.1% to 16.2%) and urinary tract infections (5.4% to 24.7%). Of 1,742 nosocomial S. aureus isolates, the percentage of MRSA rose from 12.5% in 1981 to 55.2% in 1994. The high percentage of MRSA was observed at 4 major anatomic sites of infection. In summary, significant shifts in the pathogens of nosocomial infection have occurred in the past 14 years at NTUH, and the distribution of nosocomial pathogens was similar to those reported in the United States in recent years.

HIV-1/HIV-2 3rd generation (Abbott), Wellcozyme HIV 1 + 2 (Murex), Enzygnost Anti-HIV 1/-HIV 2 (Behring), and Genelavia Mixt (Sanofi Diagnostics Pasteur) are currently registered by authorities as enzyme immunoassays (EIAs) for detecting HIV-1/2 infection. The present study dissects these reagents by means of the major antigenic components, assay principles and their actual performance. The performances have been evaluated by their test results in international panels of seroconversion, mixed titer performance and HIV-1/2 combination, respectively. Those EIA tests were further used to examine 26 potentially false-reacting samples, serial diluted sera prepared from two confirmed positive specimens and 720 specimens obtained from random blood donors in the Taipei Blood Center, Chinese Blood Services Foundation (CBSF). The results showed that, although standard sera of the mixed titer, performance and HIV-1/2 combination rows could not distinguish significantly among various EIAs, the seroconverting samples clearly showed their differences. The differences, as calculated by using 3 of 4 seroconverting sera, was a backward window period ranging from 19 to 23 days as compared to the detection of HIV-1 antigens. Together, these studies strongly suggest that assays which are capable of detecting HIV-specific IgM and IgG antibodies have a shorter seroconversion window. Furthermore, the HIV-2 antigen seems to be crucial for successful detection of anti-HIV-2. Finally, testing anti-HIV-1/2 in the routine screenings is expected not to increase the exclusion rate of blood units currently acquired from the examination of anti-HIV-1. Consequently, with both HIV-1/2 specificities and the ability of early detection, IgM/IgG-captured EIAs may represent a better screening method than assays based solely on the detection of HIV-specific IgG.

Three rapid latex agglutination kits (Aureus Test, Pastorex Staph-Plus, and StaphAurex) and one hemagglutination test kit (SlidexStaph) were compared with the conventional coagulase test for the identification of Staphyloccus aureus. A total of 192 methicillin-resistant S. aureus (MRSA), 75 methicillin-susceptible S. aureus (MSSA) and 86 coagulase-negative staphylococci and Micrococcus spp. were tested. The sensitivities of Aureus Test, Pastorex Staph-Plus, StaphAurex and SlidexStaph were 98.6, 99.4, 90.8 and 97.3%, respectively. Capsular serotypes of 27 strains of MRSA were also determined, in which 15 (55.6%) were capsular serotype 5, 11 (40.7%) were capsular serotype 8, and 1 (3.7%) was nontypeable. All the commercial agglutination kits showed 100% specificity except StaphAurex which had a specificity of only 96.5%. False-positive reactions were found in the strains of S. hominis, S. warneri and unidentified coagulase-negative staphylococci. These results suggest that Aureus Test, Pastorex Staph-Plus, and SlidexStaph are better than StaphAurex for rapid identification of S. aureus.

Streptomyces rimosus TM-55 was treated with 3% ethyl melthylsulfonate for 60 minutes to generate mutants producing high amount of amylase, and 1,283 mutants were isolated from yeast extract starch (YS) medium containing 0.1% 2-deoxyglucose. Amylase activity was primarily screened by clear zone formation on YS medium after spraying with iodine solution. Two mutants designed as D-35 and D-62 had higher amylase activity than that of the parent strain. Amylase activity of the mutants in the YS broth was 2.97- and 3.45-fold of the parent strain, respectively. With the addition of 0.1% lactose, and 2-deoxyglucose, amylase activity of the mutants D-35 and D-62 was 27-73% and 4-7% higher than that of the parent strain. With the addition of 0.1% sucrose, amylase activity of the mutant D-35 was 18.37% lower than that of the parent strain. Moreover, with the supplement of 0.1% glucose, amylase activity of both the mutants D-35 and D-62 was 3.67 and 3.40 fold of the parent strain.

The first case of hemolytic disease of the newborn (HDN) possibly caused by anti-Di(a) in a Chinese infant in Taiwan is reported. The mother had two pregnancies before but no history of blood transfusion. Her first male infant was normal, but her second full-term male one developed mild jaundice soon after birth, and the total bilirubin level was 12.1 mg/dL, 18.3 mg/dL, 23.6 mg/dL at 24 hours, 48 hours, and 72 hours of age, respectively. Total bilirubin was 9.1 mg/dL on the eighth day after receiving phototherapy and compatible blood exchange transfusion. The infant recovered uneventfully. The immunohematological study revealed that the mother was group AB, Rh (D)+; Di(a - b+), the father was group O, Rh (D)+; Di(a + b+), the infant boy and his 2-year-old brother were group B, Rh(D)+; Di(a + b+). The direct antiglobulin test (DAT) on the infant red cells was positive (4+ with polyspecific AHG; 4+ with anti-IgG). The maternal serum and infant's eluate from red blood cells showed negative reactions in routine antibody detection tests, but they contained alloantibody reacting against the Di(a+) cells by the manual polybrene test (MP) and indirect antiglobulin test (IAT) in AHG phase. The anti-Di(a) titers in the mother's serum was MP 1:256 and AHG 1:256, and in the infant's eluate was MP 1:128 and AHC 1:64 against Di(a + b+) cells. Based on the above results we conclude that the jaundice in this newborn baby was caused by maternal anti-Di(a) which was most likely induced by previous pregnancy. In conclusion, Diego blood group is a system of high value in anthropology because it accounts for the Mongoloid origin of American Indians, Japanese and Chinese. Anti-Di(a) may cause HDN, as in our case of HDN due to maternal anti-Di(a) in a Chinese infant. But in Europe and America, where practically all people are Di(a - b+) phenotypes, the system seems of no interest in parental studies as well as in blood transfusions. Owing to the Di(a) antigen is of higher incidence in Chinese population, we suggest that the Diego system should be involved in routine compatibility testing or antibody identification problems in parental studies and in blood transfusions in Taiwan.

Although Asian Taenia is closely related to T. saginata, it is a genetically distinct entity and can be distinguished from the classical T. saginata. Man is the only definite host of this parasite. The domestic pig and wild boar in Taiwan as well as domestic pig in Korea have been determined to be the natural intermediate hosts. Moreover, the pig has been demonstrated to be the most favorable experimental intermediate host. The cysticerci are situated mainly in the liver. They are smaller than T. saginata cysticerci and have a shorter developmental period of four weeks. The scolex of Asian Taenia cysticercus is often armed with two rows of hooklets. The adult worm of Asian Taenia is shorter and has less number of segments than the classical T. saginata. Recently, results of polymerase chain reaction studies indicate that the Asian Taenia is much more closely related to T. saginata than other taeniid species. Therefore, it is appropriate to designate Asian Taenia as a new subspecies of Taenia saginata asiatica. People in the Asian-Pacific region acquired the infection by eating raw or undercooked meat and/or viscera of pigs. Human experimental infections have succeeded in confirming the life cycle of Asian Taenia and the transmission pathway of the infection. In addition, multiple infection occurs very often and the infection has a family pattern. "Discharge of proglottids" is the most important clinical manifestation which is also useful in the diagnosis. Praziquantel is the drug of choice. The infection of Asian Taenia can be prevented by avoiding to eat raw or undercooked meat and viscera of pigs in the endemic regions.

To investigate the actin response to chemotactic stimulation of neonatal neutrophils, we developed a new procedure to measure neutrophil F-actin content directly in microvolume whole blood (100 microliters sample each test). Using this procedure, we compared neutrophil actin response to N-formyl-methyonyl-leucyl-phenylalanine (FMLP) between groups of normal neonate and adult volunteers. Relative F-actin content (FMLP/control ratio) of neonatal neutrophils is significantly lower than those of adult volunteers' neutrophils both at 30 sec (1.94 +/- 0.34 vs. 2.25 +/- 0.31; n = 16, p < 0.05, t test) and 60 sec (2.23 +/- 0.19 vs. 2.40 +/- 0.27; n = 16, p < 0.05, t test) after FMLP stimulation. These results provide new evidence of impairment of neutrophil actin response in the neonate, which may partially explain the observed chemotactic defect in neonatal neutrophils.

Quality assurance programs have been established during the last two decades in developed countries to promote high quality performance in clinical laboratories. In Taiwan, such a program for clinical microbiology laboratories has been in place since July 1987. It has been supported by the Department of Health, Executive Yuan, R.O.C. and was set up by the authors. The manpower status, facilities and equipment, and performance of clinical laboratories were investigated during the first year and standards of laboratory quality were recommended. Since then, under a continuing education program, we have conducted seminars, symposia, workshops, short-courses or panel discussions approximately 4 times a year. There have been about 150 participants per session and they have come from local hospitals (primary care hospitals), regional hospitals (secondary care hospitals) and medical centers (tertiary care hospitals). Proficiency test specimens or external unknown specimens were sent to all the laboratories twice a year and approximately 3 specimens were used each time for the evaluation of each laboratory's diagnostic capability and quality of service. Results indicated that there were tremendous improvements in the quality of laboratory performance. At the same time, several laboratory manuals describing the methods of quality control of clinical specimens, test procedures, media and reagents, personnel management and a compilation of reports etc. were published as guidelines of basic requirements for each level of the laboratories. For local hospital laboratories in remote areas, several regional hospitals or medical centers with high quality laboratories were selected to serve as back-ups. Our evaluation has shown that the performance and quality of service provided by most clinical microbiology laboratories in Taiwan have now reached nearly the level of those found in the so-called "developed countries".

Monoclonal antibodies (MoAbs) specifically against Japanese encephalitis virus (JEV) were generated by fusion of immunized mouse spleen cells with NS-1 myeloma cells. Nakayama-NIH (Na) and three Taiwan local strains of JEV, i.e., TL isolated from a patient's brain in 1965, NT109 (JE7) isolated from Cx. tritaeniorhynchus in 1985, and RP9, a plaque purified clone of NT109, were used in the immunization. The specificities of moAbs were determined by immunoprecipitation and western blotting, using JEV-infected cell lysates. They were confirmed by the same methods using recombinant JEV proteins as antigens. From Na immunization, 4 anti-E, 3 anti-NS1 and 3 anti-NS3 moAbs were generated. Seventeen anti-E, three anti-NS1 and three anti-NS3 specific moAbs were generated from mice immunized with Taiwan local JEV strains. Overall 21 anti-E, 6 anti-NS1, and 6 anti-NS3 moAbs were produced and characterized. The isotypes of these moAbs were also determined and described. Interestingly, a majority of the moAbs generated for RP9 were IgG1 isotype. In conclusion, 33 moAbs specific to JEV were generated and characterized, and some of these anti-JEV moAbs were made against Taiwan local isolates. These moAbs provide a powerful tool to study JEV, especially the antigenic properties of Taiwan's local strains.

A rapid and easy method of slide agglutination test for the detection of human tetanus antitoxins was developed in this study. Testing reagents were prepared from carboxylated polystyrene latex particles with tetanus toxin by soluble carbodiimide. The test was performed on a glass slide with a drop of test sample and a drop of testing reagent. The agglutination reaction was usually completed within five minutes. Sensitivity of this test for tetanus antitoxins can be reached at 0.125 IU/ml. Therefore, the latex agglutination test can be used to determine the immune status of a patient in an emergency.