Characteristics of virulence signs of enteroinvasive Escherichia coli (EIEC) isolated in CSFR and Bulgaria in 1988-1990.

During 1988-1990 a total of 345 virulent and avirulent strains of enteroinvasive E. coli (EIEC) were isolated from human faeces in microbiological laboratories in Prague and Sofia. This group of strains belonged to a total of 11 serotypes. The most frequently encountered serotypes in both laboratories were: 0124, 0164 and 028ac. From patients 205 strains were obtained and from healthy subjects 140 strains of EIEC. In all strains the following signs of virulence were investigated: biochemical properties, serotypes, Serény's test, test on HeLa cells, sensitivity to colicine JS and the plasmid profile. The presence of high molecular plasmid 140 MDa correlated closely with positive results of the above mentioned tests. Plasmid 140 MDa was more frequently present in E. coli strains isolated from faeces of patients (in 76.09%) than in strains from healthy subjects (in 23%). The strains circulating in the healthy population were in the majority avirulent.

Experimental thyroiditis in guinea pigs and rabbits. Immunization with thyroglobulin and bovine thyroid gland suspension.

Morphological changes in the thyroid glands of the guinea pigs with autoimmune thyroiditis (EAT) experimentally induced by thyroglobulin (TGL) or immunization by the suspension of thyroid gland cells with CFA manifested mainly by atrophy and alterations of follicular cells, fibrotic tissue changes, formation of inflammatory lymphoplasmocytic infiltrations, multiplication of C-cells and by the increase in the proportion of lymphocytes with activated nucleoli in the tissue. The antigenic effects of TGL differed from those of the cell suspension; the effects of TGL participated especially in the formation of the infiltrates, the effects of cell suspension participated in the diapedesis of mononuclears and in the multiplication of C-cells. The findings correspond to the principal findings in human autoimmune lymphocytic thyroiditis. In an electron microscope, strongly dilated cisterns of endoplasmic reticulum (ER) and multiplied mitochondria in the cytoplasm of altered follicular cells were found. The wall of the follicles exhibited fully intact or altered C-cells. The latter had a large number of granules in cytoplasm with an unusually clear medullary substance. In the rabbit thyroid glands no morphological changes were observed following the immunization with both antigens. TGL antibodies examined immunohistochemically in the sera were present in all the sera of guinea pigs immunized with TGL and CFA. The antibodies determined by dot immunodetection were present in the sera of all guinea pigs immunized with TGL+CFA, the titres reached the level of 1:81 to 1:729; the highest titres were observed in the guinea pigs following the immunization by dose of 7.7 mg/kg after 12 weeks of immunization.

[Use of markers of hospital strains in studying the occurrence of nosocomial infections]. / Vyuzití markeru nemocnicních kmenu pri sledování výskytu nozokomiálních nákaz.

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.

[Bacterial contamination of arthropods in a health facility]. / Bakteriální kontaminace clenovcu ve zdravotnickém zarízení.

At 55 sites of a health institution in July and September 1990 a total of 161 specimens of arthropods were detected, 30 outdoors and 131 on the premises of the health institution. On their bodies 116 bacterial strains were isolated, mostly Gram-negative rods (more than 85%), in particular spp. Enterobacter, Acinetobacter, Klebsiella, Citrobacter and Pseudomonas. Gram-positive cocci accounted for cca 12%, in particular strains of S. haemolyticus and S. hominis. The greatest number of strains was detected on bodies of cockroaches, flies, Chironomus and Tenebrio. In about one third of strains the diffuse disk test revealed resistance to more than three antibiotics. The investigation was supplemented by microbiological examination of strains from a hospital environment (45 smears) and strains from biological material (82 specimens), from patients with nosocomial infections.

Epidemiological role of arthropods detectable in health facilities.

A total of 161 arthropod specimens were collected from 55 sites in a health care facility during July and September 1990. Of the 116 bacterial isolates obtained from their body surfaces 6% were from parasites (mosquitoes), 59% from eusynanthropic arthropods (Tenebrionid beetles, flies, German cockroaches, wasps), 16% from hemisynanthropic arthropods (ants, spiders) and 19% from occasionally encountered insects (non-biting midges, moths, beetles). Most (88%) of the isolated bacteria were Gram-negative rods of the species E. coli, Enterobacter, Klebsiella, Citrobacter, Proteus, Serratia, Pseudomonas and Acinetobacter. Gram-positive cocci accounted for 13% of isolates and were primarily represented by coagulase-negative staphylococci. The highest isolation rates were from body surfaces of flies, German cockroaches, non-biting midges (Chironomids) and Tenebrionid beetles. About one third of all isolates were resistant to more than three antimicrobials using a standard disc diffusion assay. The presence of multiple resistance to antibiotics was observed in two thirds of Enterobacter isolates, namely those of Enterobacter cloacae from the body surface of Germany cockroaches, in 13% of Citrobacter spp and in 8% of Klebsiella spp as well as Acinetobacter calcoaceticus strains. Strains of Morganella and Hafnia species were very infrequent but all of them shared resistance to the antibiotics tested. In contrast, strains of Serratia spp were relatively antibiotic-sensitive. The group of isolated Gram-positive organisms was represented by two strains of Staphylococcus hominis and one strain of Enterococcus sp, all of them were multiply-resistant to antimicrobials.

Arthropods in a hospital and their potential significance in the epidemiology of hospital infections.

Synanthropic and other arthropods were collected and examined for microbes in the summer seasons of 1988 and 1990. The collection was performed in a Prague hospital with departments situated in separate buildings, each surrounded by a park. In 1988, the most attention was given to flies (35 species collected) found outside between the buildings. In 1990, all arthropods found inside the buildings (particularly in the departments of dermatology and urology) were studied. A total of 30 taxons were identified. The microbes found on the bodies of arthropods were isolated in both seasons. In 1990, the hospital environment and biological material from patients (urine, pus) were also examined for the presence of microbes. Altogether 108 strains (21 species) and 116 strains (25 species) were isolated from the arthropods' bodies in 1988 and 1990, respectively. The ecological characterization of the arthropods and results of microbiological studies show that synanthropic arthropods play a significant role in the epidemiology of hospital infections.

On the microbiological diagnostics of Campylobacter jejuni.

Investigation of campylobacteriosis cases in 1983-1989 resulted in the isolation of a total of 245 antigenically identified and 23 unidentified strains from humans, animals and foods. A commonly accepted method developed in 1985 using our own experience was used for strain isolation and culturing. A variety of nutrient media in combination with different supplementary substances (antibiotics, growth factors) and additives, such as horse serum, were verified as well as filtration and Fortner's procedures. The best results were obtained when material was stored in thioglycolate transport medium accompanied by cold enrichment (24 h at 4 degrees C) and repeated inoculation into appropriate solid nutrient medium. Owing to the simple culturing of C. jejuni, the number of not elucidated diarrheas was reduced and the incidence of campylobacteriosis (approximately 12 %) is higher than that of salmonellosis and shigellosis. A total of 245 C. jejuni strains was classified using Kahlich's antigenic scheme. The incidence of serovars 1 and 2 was greater than 10 %. Five serovars (13, 17, 25, 26 and 27) were represented by only one strain. The study of campylobacteriosis also revealed the long-term excretion of C. jejuni by convalescents (71 days at most) as well as the occurrence of family outbreaks. Procedures were developed to ensure short-term and long-term (freeze-drying) preservation of isolated strains. The number of cases reported by microbiological laboratories in the framework of the Hygienic Service throughout Czechoslovakia suggest an increase in positive findings with C. jejuni as the etiological agent.

Characterization of Campylobacter jejuni strains occurring in the USSR and the Czech Republic.

In 1986-1989 the microbiological laboratory in Prague obtained 100 Campylobacter jejuni strains while its counterpart in Moscow gained 120 such strains. The strains were primarily isolated from humans with diarrheal disease, from domestic and wild animals and from the environment. Most C. jejuni strains were successfully specified and classified using a Czechoslovak serotyping scheme proposed by Kahlich. Serotypes 1, 2, 7, 15, 22 and 24 occurred most frequently in the Czech Republic whereas in the Soviet Union the most common serotypes were 7, 16, 5, 2, 1. The proportion of strains which could not be identified in the serotyping scheme was about 10% in the USSR and 20% in the Czech Republic. Our findings suggest differences between the USSR and the Czech Republic in the prevalence and incidence particular serotypes of C. jejuni strains.

[Hemolytic-uremic syndrome--microbiological study]. / Hemolyticko-uremický syndrom--mikrobiologické setrení.

In autumn 1988 in one locality of the North Bohemia region young children developed severe diarrhoea and the children were sent because of their serious clinical condition with the diagnosis of haemolytic-uraemic syndrome (HUS) to the Prague-Motol hospital. The probable aetiological agent which was detected was Escherichia coli producing verotoxin (VTEC)--026:H11, 026:H?, O157:H7, 05:H- and 01:H?. Biotyping and serotyping of the strains was made, the verotoxin level was assessed and their sensitivity to antibiotics was tested. Concurrently contacts were examined and suspect colonies of Escherichia coli were subjected to bio- and serotyping, however, none of the serovars found in the sick children was detected.

[Microbiological diagnosis of microorganisms tentatively designated as "SP organisms"]. / Príspevek k mikrobiologické diagnostice mikroorganismu provizorne oznacovaného jako "SP organismus".

The authors describe the biochemical characteristics of two strains described as "SP organism". This microorganism incertae sedis resembles from the biochemical aspect (oxidase+, mannite-, dextrose+ with gas) the species Pasteurella aerogenes; contrary to the latter it does not break down urea and differs also as regards the morphology of colonies, which on blood agar are coarser; it also has a higher content of G + C in DNA than Pasteurella. It is a pathogen of rodents. The authors describe two isolates, the first is obviously an incidental finding from the faeces of a 5-year-old girl who was symptom-free, the second is from the contents of an abscess of a nutria. For comparison also biochemical characteristics of known aerogenic pasteurellae and Pasteurella-like strains are given.

Prenatal development of the cat thyroid: immunohistochemical demonstration of calcitonin in the "C" cells.

The presence of calcitonin in the cat thyroid was studied immunohistochemically in a series of gland development. The first positive cells are to be found on the 38th day of gestation, i.e. 1-2 days after level nine of ontogenetic development has been reached. The cytoplasm of these cells form only a narrow border round the nucleus. With advancing development the number of calcitonin-positive cells rises, the cytoplasm becomes intensely positive and its amount increases. From approximately the 50th day of prenatal development, the initially diffusely scattered, solitary calcitonin-positive cells are gradually replaced by groups of cells, which begin to occupy a characteristic position in relation to the follicular epithelium. The largest quantity of calcitonin-positive cells is found in foetuses about to be born. In non-pregnant adult cats, the incidence of immunohistochemically calcitonin-reactive cells is more sporadic and their distribution in the lobes of the thyroid is uneven.