Ceskoslovenska epidemiologie, mikrobiologie, imunologie最新文献

Based on assembled data from the literature and oral communications as well as findings in the laboratory, the author concludes that an enteroviral aetiology of diarrhoeal diseases can be taken for granted in many instances. Enteroviral gastritis is not frequent nor serious and is usually not encountered in winter but rather in summer under conditions with a higher standard of hygiene. The ratio of enteroviruses in epidemics of gastroenteritis and in the aetiology of enteritis within the framework of epidemics with other manifestations of enteroviral disease is very variable and there is no generally valid frequency which could serve for orientation. Virological and serological diagnosis of enteroviral diarrhoea would not be expedient in winter, it is, however, useful in summer and in epidemics affecting neonates and young children. In general, less attention is paid to an enteroviral aetiology or diarrhoea, as compared with thorough assessment of an enteroviral aetiology in severe forms of the disease. Attention is drawn to the usefulness of a more detailed investigation of properties of strains of polioviruses isolated from patients with diarrhoea.

During 1987-1989 the authors investigated by electrophoresis in a polyacrylamide gel (PAGE) the circulation of rotavirus electropherotypes in younger children admitted with diarrhoeal diseases to the infectious and paediatric clinic of the Faculty Hospital in Plzen. From 275 specimens of faeces with evidence of rotaviruses the electropherotype was assessed in 165 cases (60%). During the investigation period among the children five basic electropherotypes circulated. The authors did not reveal a predominance of a certain type. In the aetiology of 24 nosocomial infections, where the electropherotype was diagnosed, only types were represented found during the appropriate period in children admitted to the investigated department.

Based on the long-term follow-up of the incidence of some infectious diseases in the district and calculations of the actual number of infected subjects, the authors present an estimate of the ratio of susceptible and immune subjects during the unimpaired epidemic process. The epidemic process develops from the lowest range of immune subjects and stops at the highest range. The highest range thus gives the ratio of immune subjects which must be achieved or maintained by active immunization to achieve elimination of a given infection. The authors demonstrate on the model infection the mechanism by which after immunization the shift of infections to higher age groups occurs, and during introduction of the infection not only contact infections occur, but epidemic incidence develops. The restoration of some infections after years of elimination is to a restricted extent a natural phenomenon and does not imply failure of active immunization.

In conjunction with an investigation extending over several years, focused on the understanding of the importance of Helicobacter pylori in inflammatory gastric disease, the authors examined a group of 1242 patients. In fifteen they detected by microscopic examination the presence of helical bacteria described in the literature as Gastrospirillum hominis. The cultivation test was not positive. In three patients in addition to these bacteria also the presence of Helicobacter pylori was detected. Sera of eight patients with Gastrospirillum hominis were investigated by the ELISA test Helico-G f. Porton Cambridge; antibodies against Helicobacter pylori were found in three patients (incl. two with the concurrent presence of G.h. and H.p.). In sera of the remaining five patients antibodies were not detected.

The authors tried to standardize the method of assessment of the minimal inhibitory concentration (MIC) of antimycotics for the evaluation of the sensitivity of opportunistic causal agents of mycoses. They paid attention to factors which cause deterioration of the reproducibility of tests and lead to intra- and interlaboratory variability of results. In conjunction with this the authors drew attention to the lack of uniformity of views on the application of these tests in clinical practice. In the author's view the reservation pertaining in particular to an inadequate correlation of results in vitro and in vivo do not cast doubts on the expedience of laboratory assessment of sensitivity. Testing of systemic antimycotics with a low pharmacotherapeutic index and a relatively high frequency of secondary resistance is particularly justified. In those instances assessment of MIC values is a significant component of monitoring of adequate antifungal chemotherapy, in particular when antimycotics are administered for prolonged periods to patients with altered immunity.

The dynamics of bacteremia on white mice subcutaneously infected with an inoculum of 100 and 10 cells of F. tularensis (strain 273) was compared in two parallel experiments. The rise of bacteremia was relatively uniform, about 3 logarithms a day in both groups of animals, so that it reached values of 10(9)-10(10) cells per 1 ml of blood ante finem. Larvae of Ixodes ricinus were fed on white mice in different stages of bacteremia, so that groups of ticks with different degrees of infection were obtained. Our results of quantitative examination show an evident correlation between the degree of bacteremia of the host and the degree of infection of ticks. The highest values of positivity 10(6)-10(7) cells were recorded in larvae, which finished their feeding on the day of the host's death, during the time when bacteremia was reaching the highest degree 10(10) cells per ml of the blood. Persistence of the agent in the organism of infected larvae could be observed up to hatching, under given experimental conditions one month after infection. In nymphs developed from larvae with the highest degree of infection this ability was preserved in about one third of individuals still after 5 months of starvation. In ticks with low degrees of infection it disappeared during the experiments.

Semipurified urease and outer membranes of Helicobacter pylori were isolated and used as antigens for the construction of new ELISA tests for the serodiagnosis of infections caused by this microorganism. The highest discriminating capacity between infected and not infected subjects was obtained by the test detection of IgG antibodies against the urease antigen which reached a 100% sensitivity, 90% specificity, a 100% negative and 91% positive predictive value. Examination of sera of healthy children and blood donors revealed the possibility of asymptomatic infection and an increase of specific antibody levels with age.

The authors present examples demonstrating that in the last decades we witnessed the discovery of new nosological units and their infectious agents, the detection of the infectious origin of "old" diseases the aetiology of which was still recently obscure, infectious attacks of people by diseases which were considered animal infectious only, as well as the more frequent incidence of opportune infections due to impairment of the immune state of the human organism. These changes have many reasons such as the development of properties of microorganisms, lifestyle changes of the human population, advances in medicine, and last but not least improving microbiological diagnosis. Attention is drawn to the fact that even in a time when so-called diseases of civilization are in the foreground of interest our awareness of infectious diseases must not slacken. Only all-round international surveillance can prove successful.

The submitted paper deals with one of the possible aspects of the investigation of nosocomial infections, i.e. investigations of the properties of hospital strains, their importance and possible use. The incidence of bacterial hospital strains was investigated in a surgical department of a district hospital of the North Bohemian region in October 1990; at the time of the survey 29 nosocomial infections (36.1%) were revealed by the prevalence method. Bacterial hospital strains were isolated from patients with a nosocomial infection, from the attending staff and the hospital environment. The following markers were investigated: biotyping, phagotyping, serotyping, toxin production, sensitivity to antimicrobial substances and sensitivity to disinfectants. Based on results of marking of hospital strains 7 incidences with a possible epidemiological association were detected where the hospital strain of equal or very similar properties dominated. The results of the investigation confirmed the important participation of the attending staff in the spread of nosocomial infections, in particular via contaminated hands, and drew attention to shortcomings as regards adherence to the hygienic and epidemiological regime in the investigated department.

The author describes the use of polyclonal antibodies against gentamicin by competitive ELISA. The author used polystyrene microplates as the solid phase for antibodies. Gentamicin was marked by horse radish peroxidase and a known amount of thus labelled gentamicin competed for a bond with an antibody with an unknown amount of gentamicin in serum. The method requires 10 microliters non-diluted serum and the results can be evaluated within one hour. The accuracy of the method according to values of the coefficient of variation (CV) is 9.0-13.2% in different tests and 5.2 to 9.2% within one examination.