Janina Goldhar

Anti-Escherichia Coli Adhesin Activity of Cranberry and Blueberry Juices

For many decades, cranberry juice has been recommended by physicians in North America for the treatment or prevention of urinary tract infections (UTI). However, until recently, no experimental evidence has been presented for the purported beneficiary effect of the juice, nor for its mechanism of action. For a while, it was believed that the antibacterial effect of the juice is due to its ability to acidify urine and thus to inhibit bacterial growth but no support for this was found (Kunin, 1987; Bodel et al., 1959).

Extraction and properties of nonfimbrial mannose-resistant hemagglutinin from a urinary isolate ofEscherichia coli

A mannose-resistant hemagglutinin (MRH) was extracted from an agar-grown urinary isolate ofEscherichia coli (827) by heating the organisms at 65°C for 1 h. Both MRH and the organisms agglutinated erythrocytes from human (group A) but not from seven other animal species tested, but were devoid of any detectable fimbriae as examined by electron microscopy. MRH was sensitive to pronase or 100°C heating, but not to trypsin or periodate, could not be sedimented by ultracentrifugation 149,000g, and passed the void volume of Sepharose-4B column. MRH inhibited the adherence of bacteria to tissue culture cells. The results suggest thatE. coli human isolate produces mannose-resistant hemagglutinin, which is located on the cell surface in nonfimbrial form and probably mediates adherence of the bacteria to eukaryotic cells.

Plasmid profiles and antimicrobial susceptibility of Campylobacter jejuni isolated from Israeli children with diarrhea.

Thirty Campylobacter jejuni (C. jejuni) strains isolated from stools of Israeli children with enteritis were tested for sensitivity to eight antimicrobial agents (MIC) and the presence of plasmids. It was found that all the isolates were sensitive to ciprofloxacin, ofloxacin, furazolidone and erythromycin. Of the 30 strains tested, 21 (70%) were found to be tetracycline-resistant, a relatively high resistance rate as compared with data from other countries and previous reports from Israel. Plasmids were detected in 17 out of 30 C. jejuni isolates (55.6%). A total of nine different plasmid profiles could be distinguished; six profiles were represented by one strain each. Of the 21 tetracycline-resistant strains, plasmids were found in 17 isolates (80%) carrying from 1-2 to 5 plasmids of various sizes. No plasmids were found in tetracycline-sensitive strains, with the exception of one isolate which contained a 24.4 MDa plasmid and was co-trimoxazole-resistant. Our studies indicate a relatively high percentage of tetracycline-resistant C. jejuni isolates in the Tel Aviv area. In 80% of these strains, various plasmid profiles were detected.

Enterotoxigenic Escherichia coli (ETEC) isolated in the Tel-Aviv (Israel) area.

The prevalence of enterotoxigenicE. coli (ETEC) as a pathogenic agent of diarrhoea in the Tel-Aviv (Israel) area was determined, and the isolatedE. coli strains characterized. During three periods (summer 1977, summer 1978, and summer 1979), a total of 335 specimens were tested for the presence ofE. coli producing LT and ST toxin. Most of the specimens were from sporadic ambulatory diarrhoea cases (children and adults) attending a number of health care clinics in Tel-Aviv. Two to five colonies were tested from each sample. ETEC was detected in 69 cases (20%): LT/ST strains were isolated from 9 cases (2.7%); LT from 7 cases (2.1%); and ST from 53 cases (15.2%). ETEC was isolated in all age groups.In 19 specimens, 2 or more of 4 colonies tested were enterotoxigenic and were identical according to biotype, antibiotic sensitivity, and serogroup. These findings suggest that enterotoxigenic strains predominated in the bacterial population of the stool specimen. Part of the isolated ETEC strains belonged to serotypes already known as enterotoxigenic in different geographic areas of the world. The most frequently encountered were serogroups O8 (9 cases) represented by at least three serotypes, among them O8:K40:H9, and serotype O6:K15:H16 (5 cases); a number of serotypes were represented only by two cases or by single cases. Among 16 LT-producing stains (LT/ST and LT-only), 13 belonged to 3 serogroups, while ST-only strains represented a large spectrum of serotypes, some of which are now known as enterotoxigenic. Several serotypes common in other geographical locations were not detected.

Nonfimbrial Adhesins of Escherichia Coli

Pathogenic Escherichia coli exhibit a variety of adhesins classified according to their morphology, antigenic structure or receptor specificity.

Iron-regulated proteins in outer membranes of Campylobacter jejuni diarrhoea isolates and immune response to the proteins in patients

The outer membrane protein (OMP) profiles from 8 Campylobacter jejuni and 5 Campylobacter coli fecal isolates grown under various conditions were compared by SDS-PAGE. The bacteria were grown under usual conditions, in iron-deficient medium (Dip) and on iron-supplemented medium (Fe). The OMP profiles of most bacterial strains grown under usual conditions, or in the Fe-supplemented medium, contained four major bands of approximately 31, 45, 63-66 and 97 kDa, and in addition, a number of minor bands. It was found that OMP from 10 of 13 strains tested and grown on iron deficient medium contained an intensive band of a protein in the molecular weight region of 76 kDa which was lacking in the OMP of bacteria grown in the presence of iron (iron-regulated protein). Sera from 11 children with C. jejuni infection analyzed by Western blot recognized the 76 kDa bands, in contrast to only one out of 10 control sera from healthy children. The Western-blot experiments demonstrated also various bands of other OMP components, both in OMP-Dip and OMP-Fe. The 45 kDa (porin protein) was recognized by all 11 serum samples from C. jejuni-infected patients and in 8 out of 10 control sera. The data suggested that the 76 kDa iron-regulated protein was expressed by bacteria during infection and it stimulated the immune response in children infected with C. jejuni.

Molecular cloning and characterisation of the genes for a non-fimbrial adhesin from Escherichia coli☆

A non-fimbrial adhesin (NFA-1) from the uropathogenic Escherichia coli strain 827 responsible for agglutination of human erythrocytes was cloned using the cos 4 cosmid vector. A clone was isolated which promoted haemagglutination and showed the same biological properties as the adhesin produced by the wild type strain. Both express adhesin at 37 degrees C, but not 18 degrees C nor in the presence of 1% glucose. Adhesin purified from the clone formed high molecular weight aggregates which were resolved to the 21 K dalton subunit protein seen in the wild type strain on denaturation. Binding to human kidney cells by the clone and the wild type E. coli, from which the genes were cloned, were compared in an ELISA assay and shown to be the same. The genes for the adhesin were isolated on a 15.5 kilobase BamHI-EcoRI fragment which was subjected to gamma delta mutagenesis. The NFA-1 operon was localised to a 6.5kb region of this fragment.

Phagocytosis of Escherichia coli mediated by mannose resistant non-fimbrial haemagglutinin (NFA-1)☆

We examined the interaction between a urinary isolate of E. coli carrying non-fimbrial MR adhesin (NFA-1) and human polymorphonuclear leukocytes (PMN). We found that the organisms attach to PMN and the attachment was dose dependent and saturable. It was inhibited by isolated NFA-1, but not by mannoside. Recombinant plasmid encoding NFA-1 adhesin conferred binding capacity on a non-adhesive strain. The attachment of the bacteria carrying NFA-1 to PMN was associated with oxidative burst and inhibited by isolated NFA-1. The data taken together suggest that NFA-1 mediates the attachment of the bacteria to PMN. The attachment is followed by ingestion and killing of the organisms, but at a slower rate than with bacteria bound via type 1 fimbriae.

Invasive ability of C. jejuni/coli isolates from children with diarrhea and the effect of iron-regulated proteins

The invasive ability of C. jejuni/coli strains isolated from children with diarrhea was studied using an in vitro HEp-2 cell invasion assay. The ratio between the number of intracellular bacteria and the number of bacteria in the inoculum was determined (invasion index). It was found that under anaerobic conditions, there was a significant decrease in the invasion index as compared to standard conditions (5% CO2). Of 11 strains tested, seven were determined as invasive on the basis of invasion indexes within the range of 0.0002-0.01. In a previous study [D. Schwartz et al., Zbl. Bakt. 280, 338-347 (1994)], it was found, that most of the C. jejuni/coli isolates tested produced an outer membrane protein when grown under conditions of iron depletion (IRP). The IRP were detected in eight of the nine strains tested in the present study (five invasive and three non-invasive strains). In one non-invasive strain, IRP was not detected. When kept under conditions of iron depletion, one of the invasive strains exhibited a significant increase in invasive capacity. The results suggest that iron depletion seems to stimulate the invasion capacity of C. jejuni/coli in vitro.

Lysogeny and lysosensitivity in Shigella dysenteriae group of bacteria. II. Receptor sites for temperate phages and serological relationships of indicator strains Sh. boydii 15-7489, Sh. dysenteriae 2 and Sh. dysenteriae 7.

Receptor substances for temperate phages, which were isolated from lysogenicSh. dysenteriae strains, were tested. These substances were obtained fromSh. boydii 15-7489, which served as an indicator and propagating strain, and fromSh. dysenteriae 2 andSh. dysenteriae7, which were indicator strains.On the basis of agglutination and precipitation testa,Sh. bodii 15-7489 andSh. dysenteriae 2 were shown to be serologically related while no relationship was found betweenSh. boydii 15-7489 andSh. dysenteriae7.According to experimental data, it was suggested that phage receptor sites are localized in the protein component of the somatic antigen. This component, occurring in all three examined strains, possessed common antigen properties, as was shown by use of receptor neutralization test.