Borrelia burgdorferi in ticks and dogs in the province of Vojvodina, Serbia

Lyme disease is a tick borne zoonotic infection, caused by Borrelia burgdorferi s.l. bacteria. For the transmission of the disease, the presence of ticks is a prerequisite. Lyme borreliosis mostly occurs in people and dogs, but it may occur in other animals. Ticks which carry B. burgdorferi s.l. in Serbia are of the Ixodes ricinus specis. In Serbia, Lyme disease was detected for the first time in the late '80-es. In dogs, clinical symptoms may occur even months after a tick bite, and include weakness, lymphadenopathy, fever, lameness, arthritis, etc. In our survey, we have observed tick and dog populations in the province of Vojvodina (northern part of Serbia). I. ricinus ticks were collected and examined for the presence of B. burgdorferi s.l. in several chosen locations. In addition, blood samples were collected from house dogs and pets from the same locations, and analyzed for the presence of antibodies specific for B. burgdorferi s.l. The results showed a mean infection of ticks of 22.12%, and a mean seroprevalence of Lyme disease in dogs of 25.81%. We conclude that in Vojvodina there is an actual risk of Lyme borreliosis for other animals and humans, because of the persistence of B. burgdorferi s.l. in both tick and dog populations.

The prevalence of Shiga toxin-producing Escherichia coli in domestic animals and food in Serbia

Faecal samples of 2660 domestic animals from 116 farms and 956 samples of food were examined for the presence of Shiga toxin-producing Escherichia coli (STEC). STEC was recovered from 126 (15.3%) cattle, 135 (11.3%) pigs, 135 (66.8%) sheep, 31 (73.8%) goats, 4 (1%) chicken, and 15 (1.6%) food samples. Of all STEC isolates, 21.5, 25.8 and 15% produced enterohaemolysin, alpha-haemolysin, and aerobactin respectively, 1.6% displayed localized adherence (LA) to HEp-2 cells, 27.6% were sorbitol negative, and 30% were resistant to antibiotics. Only 14 (3.1%) of the STEC isolates belonged to human infection-associated serogroups (O26, O55, O111, O128 and 0157), designated as enterohaemorrhagic E. coil (EHEC). This study revealed that STEC are prevalent in domestic animals, and to a lesser extent in food of animal origin in Serbia, but the absence of a EHEC phenotypic profile (characteristic serogroup, LA, enterohaemolysin production) in most animal STEC strains may explain the low incidence of human STEC infection in this part of the world.

[Reliabilty of the antibiogram and plasmid profile in detection of epidemic strains of Shigella sonnei]

The aim of the study was to investigate and compare the type of resistance to antibiotics and plasmid profile of Shigellae sonnei isolated at epidemics of bacillary dysentery to determine which method was most reliable in the identification of epidemic strains of that bacteria. It was investigated 130 isolates of Sh. sonnei isolated from the stools of patients in 14 epidemics of bacillary dysentery in Yugoslav Army and citizens in period from 1987 to 1993 year. On the basis of identity of studied features of all isolates originated from one epidemic, epidemic strains of Sh. sonnei could be identified in 10 (71.4%) of 14 studied epidemics by means of plasmid profile, and in 8 (57.1%) epidemics by means of determination of resistance type to antibiotics. According to that, the method of plasmid profile analysis is more reliable in identification of Sh. sonnei epidemic strains compared to the method of determination of resistance type to antibiotics.

Enteroaggregative Escherichia coli associated with an outbreak of diarrhoea in a neonatal nursery ward

Over a 9-day period in February 1995, 16 newborn babies (age range 2-11 days) and 3 infants (24, 47 and 180 days of age) in a neonatal nursery ward developed diarrhoea accompanied by pyrexia and weight loss. Known enteropathogens were not detected in their stools but Escherichia coli displaying aggregative adherence to HEp-2 cells (enteroaggregative E. coli) were found in 12 (63%) ill infants and in none of 5 well neonates (P = 0.02). The illness lasted 3-9 days (mean 5.2) in 16 babies, whereas in 3 neonates it showed a protracted course of 18-20 days. The source of infection and the mode of transmission remained unclear. The outbreak isolates manifested properties common in this new group of diarrhoeagenic E. coli: mannose-resistant haemagglutination, haemolysis on blood agar, and clump formation in liquid culture medium. They belonged to the O4 E. coli serogroup and expressed multiple antibiotic resistance.

Infrequent finding of verotoxin-producing Escherichia coli in diarrheal stools in Belgrade, Serbia

Out of 2,638 patients, with acute diarrhea, verotoxin-producing Escherichia coli (VTEC) was isolated from the stools of 8 (0.3%). There was no visible blood in their stools and none of them developed other syndromes associated with VTEC infection. None of the isolated VTEC agglutinated with O157 E. coli antiserum, while only 3 strains hybridized with the DNA probe CVD 419, designed to detect VTEC. The data obtained suggest that VTEC is not an important causative agent of acute diarrhea in Belgrade.

[Detection of parvovirus B19 in the blood of patients using DNA hybridization]

DNA assay was used in detection of parvovirus B19. The sera of 63 patients were examined and the presence of DNA virus was found in two samples.

[Typing of rotavirus strains using electrophoresis]

Polyacrylamide gels electrophoresis was used in the analysis of rotavirus genome strains isolated in the regions of Belgrade and Nis in the period 1987-1991. Ten samples were examined and the same type of motility was found.

[Detection of human papilloma viruses using in situ hybridization]

First experiences in the diagnosis of human papilloma viruses are reported. The method of in situ hybridization was used together with biotin tests for types of HPV: 6/11, 16/18 and 31/33/51. The study was performed on the preparations of of the cervix tissue with displasmic proliferation and laryngeal papilloma tissues. There have been examined 37 specimens: in 6 were found sequence of HPV genoma for types 6/11 and in 1 specimen for types 16/18 and 31/33/51/.

[Typing of methicillin-resistant Staphylococcus aureus with a specific type of resistance]

Methycillin resistant Staphylococcus aureus (MRSA) is the important causative agent of intrahospital infections (IHI) which could have epidemic character. Typization of strains is necessary for control of these infections. Fifty eight strains of MRSA with specific resistance to antibacterial agents have been isolated from patients at different clinics of our hospital. The determination of resistotype, biotype and plasmid profiles of these and control strains of Staphylococcus aureus (SA) was aimed at confirmation whether identical strains were in questions. Biotypization showed no difference between the studied and control strains while determination of the plasmid profile proved the presence of an epidemic strain which caused infection in several clinics of our hospital.

[Preparation of a DNA probe for thermolabile toxin and its use in the identification of enterotoxic Escherichia coli]

Enterotoxic Escherichia coli (ETEC) having a gene for thermolabile toxin were identified by the hybridization technique. HindIII-SmaI fragment with 423 basic pairs (dp) including subunit portions A and B of the gene for thermolabile toxin (elt) was used as the DNA probe.

Lack of association of Escherichia coli exhibiting both mannose-resistant haemagglutination and diffuse adherence to HEp-2 cells with acute diarrhoea in children

Stool specimens from 631 children with acute diarrhoea and from 277 healthy controls were tested for the presence of non-enteropathogenic, non-enterotoxigenic Escherichia coli strains which mediated mannose-resistant haemagglutination of human erythrocytes (MRHA+). Fifty-nine (34.9%) of 169 isolated MRHA+ strains but none of 210 MRHA- strains exhibited diffuse adherence (DA+) to HEp-2 cells. DA+ strains were found in 37 (5.9%) children with diarrhoea and in 22 (7.9%) controls. MRHA+/DA+ strains in comparison to MRHA+/DA- strains significantly less frequently expressed P fimbriae (10.7 vs. 73.6%), haemolysin production (12.5 vs. 63.2%), and MRHA of other species erythrocytes (21.4 vs. 84%). These data demonstrate that E. coli which exhibit the diffuse pattern of adherence to HEp-2 cells also cause MRHA of human erythrocytes. Since these strains were found with similar frequencies in children with and without diarrhoea it seems that DA is not a marker of enteropathogenicity of E. coli.

[Analysis of herpes simplex virus DNA using restriction endonucleases]

DNA of herpes simplex virus was analysed by restriction endonucleases EcoRI, BgII and HindIII. By this method it is possible to differentiate type 1 and type 2 of viruses. DNA of herpes simplex virus was prepared according to the method of Kinnunen and his collaborators which is described in detail.