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L R Trabulsi

Publications and source records attributed to L R Trabulsi.

At least 91 records · Page 5Linked to original sources
PubMed1983

Correlation between biochemical and serological characteristics of Escherichia coli and results of the Serény test.

A total of 1,335 Escherichia coli strains isolated from patients with diarrhea were submitted to the Serény test. Of these strains, 1,035 were also submitted to slide agglutination test, using antisera for invasive E. coli serogroups. Of 325 isolates that were lysine decarboxylase negative, 138 reacted with one of the E. coli antisera used. From this group of 138, 137 were positive in the Serény test. Strains that were lysine decarboxylase positive (1,010 strains) were all negative in the Serény test. These results show a close correlation between the biochemical and serological characteristics of E. coli and the results of the Serény test.

Agglutination Tests↗
PubMed1983

Enterotoxigenic and enteroinvasive Escherichia coli strains belonging to a new O group, O167.

A new Escherichia coli O group, O167, is described. Its O antigen is related to that of Shigella boydii 3. A total of 29 strains belonging to the new O group were examined. Three strains were determined to be invasive by the Sereny test and by tissue culture tests and were non-enterotoxigenic. All three were nonmotile and failed to decarboxylate lysine. A total of 26 strains were noninvasive. Of these, 25 were motile, 24 decarboxylated lysine, and 19 were enterotoxigenic, 17 producing heat-stable enterotoxin only and 2 producing heat-labile enterotoxin only. This is the first description of the occurrence of enterotoxigenic and enteroinvasive strains in the same E. coli O group.

Agglutination Tests↗
PubMed1982

Frequency of Escherichia coli strains producing heat-labile toxin or heat-stable toxin or both in children with and without diarrhea in São Paulo.

Enterotoxigenic Escherichia coli strains were isolated from 32 (13.4%) of 245 children with diarrhea and from 11 (11.4%) of 96 children of the control group. Strains producing heat-labile toxin were found more frequently in normal children than in children with diarrhea. Strains producing heat-stable toxin and both heat-labile and heat-stable toxins were isolated only from children with diarrhea. Association of these strains with diarrhea was highly significant as shown by statistical analysis. The O:H types and the colonization factors of strains producing heat-stable toxin and both heat-labile and heat-stable toxins are presented.

Bacterial Toxins↗
PubMed1980

Relationship among enterotoxigenic phenotypes, serotypes, and sources of strains in enterotoxigenic Escherichia coli.

The relationship among O groups, O:H serotypes and enterotoxigenic phenotypes was examined in 76 Escherichia coli strains isolated in Brazil from different sources. Of the 17 heat-labile and -stable enterotoxin (LT/ST)-producing strains whose O antigens were identified, 15 belonged to serotypes O6:H16 (7 strains), O63:H- (5 strains), and O139:H28 (3 strains). All 11 ST strains were in group OO128PAC, which was represented by four O:H serotypes. The 23 LT strains with the O antigen identified were distributed among serotypes of 14 O groups. Colonization factor CFA/I was not found in any of the LT strains, but it was found in six LT/ST and three ST strains. On the whole, each E. coli O:H serotype had a particular fermentation pattern. LT/ST as well as ST strains were all isolated from patients with diarrhea, whereas LT strains were isolated from patients with diarrhea, normal children, food, and river water.

Bacterial Toxins↗
PubMed1980

Transfer of a CFA/I-ST plasmid promoted by a conjugative plasmid in a strain of Escherichia coli of serotype O128ac:H12.

Escherichia coli strains belonging to serotype O128ac:H12 and producing heat-stable enterotoxin (ST) and colonization factor CFA/I were found in Sao Paulo in children with diarrhea, but not in normal children. Segregants occurred in such strains with a frequency of about 10%, which have lost the ability to produce ST and CFA/I at the same time. From one strain, both properties were transformed jointly in matings to an E. coli K-12 strain. All such ST+ CFA/I+ progeny had received two plasmids of length 97 and 64 kilobases in the matings. Insertion of a transposon, Tn5, carrying a gene for kanamycin resistance, into the two plasmids enabled us to select for kanamycin-resistant progeny in further matings. Analysis of such progeny strains in terms of plasmid content and production of ST and CFA/I revealed that the larger plasmid carries the genes for St and CFA/I and is not self-transmissible, whereas the smaller plasmid does not carry any recognizable phenotypic traits, but is conjugative and promotes cotransfer of the larger plasmid with a frequency of about 30%.

Colony-Forming Units Assay↗
PubMed1980

New invasive Escherichia coli strain.

A new invasive Escherichia coli serogroup is described. Its O antigen is identical to the O antigen of Shigella boydii 3. We propose the designation of E. coli São Paulo for this serogroup until the situation of its O antigen is settled.

Antigens, Bacterial↗
PubMed1980

Biochemical and cultural characteristics of invasive Escherichia coli.

The biochemical characteristics of 97 invasive Escherichia coli strains of different O serogroups were studied. Considered as a group, the behavior of the strains was quite variable. However, none of them decarboxylated lysine and all but seven strains, belonging to the O124 serogroup, were nonmotile. The growth of 25 strains obtained on MacConkey, salmonella-shigella, xylose-lysine-desoxycholate, and Hektoen enteric agars was compared. MacConkey and Hektoen enteric agars yielded the highest average growth for these strains, whereas salmonella-shigella agar had the lowest average counts.

Amino Acids↗
PubMed1979

Passive immune hemolysis for detection of heat-labile enterotoxin produced by Escherichia coli isolated from different sources.

Fifty-one strains of Escherichia coli isolated from humans, swine, food, and water and identified as enterotoxinogenic by the Y-1 adrenal cell assay, were examined for heat-labile enterotoxin (LT) production by the passive immune hemolysis test. Cholera antitoxin, anti-choleragenoid and anti-LT were used as antisera. Cholera antitoxin was much more potent than anti-choleragenoid and LT antiserum in the detection of LT-positive strains. All strains isolated from pigs and sausage were negative in tests made with LT antiserum. A few strains isolated from humans, food, and water also gave negative results. These data showed that the passive immune hemolysis test is not as efficient as the Y-1 adrenal cell assay in the detection of enterotoxinogenic E. coli strains.

Bacterial Toxins↗
PubMed1979

Invasive strain of Escherichia coli belonging to O group 29.

A strain of Escherichia coli isolated from a child with diarrhea was biochemically similar and antigenically identical (O and K antigens) to the standard strain of E. coli O group 29 and was positive in the Serény test for invasiveness, which suggests that it can cause a Shigella-like illness.

Carboxy-Lyases↗
PubMed1979

Studies on the antibacterial activity of two new acylureidopenicillins, mezlocillin and azlocillin.

The antimicrobial activity of 6-[(R)-2[3-methylsulfonyl-2-oxo-imidazolidine-1-carboxamido]-2-phenylacetamido]-penicillanic acid sodium salt (mezlocillin, Baypen) and 6-[(R)-2-(2-oxo-imidazolidine-1-carboxamido)-2-phenylacetamido-a1-penicillanic acid sodium salt (azlocillin, Securopen) was measured against 545 clinical isolates, including gram-negative rods, gram-positive cocci and Bacteroides. Mezlocillin was more effective than azlocillin against the majority of the strains studied, but azlocillin was more effective against Pseudomonas strains. The minimal bactericidal concentration was equal to the minimal inhibitory concentration for the strains tested, but it was twice or four-fold as high for Staphylococcus.

Azlocillin↗
PubMed1979

Synergistic action between sisomicin and mezlocillin against gram-negative bacteria and Staphylococcus aureus.

The combined effect of sisomicin and 6-[(R)-2-[3-methylsulfonyl-2-oxo-imidazolidine-1-carboxamido]-2-phenyl-acetamido-a1-penicillanic acid sodium salt (mezlocillin, Baypen) was studied against 50 bacterial strains, including Pseudomonas aeruginosa, Proteus spp. Klebsiella-Enterobacter, E. coli and Staphylococcus aureus. No antagonism or indifference was detected with the strains studied. Both antibiotics were synergistic against 62% of the strains, and partially synergistic against 38%. Out of the bacteria studied, Staphylococcus aureus was the most susceptible to the combined action of sisomicin and mezlocillin.

Bacteria↗
PubMed1975

Unusual Enterobacteriaceae: lactose-positive Salmonella typhimurium which is endemic in São Paulo, Brazil.

Since 1971 a lactose-positive (lac+) Salmonella typhimurium variety Copenhagen has been endemic in the city of Sao Paulo. The strain is a strong lactose fermenter and resembles Escherichia coli on primary plating media and in triple sugar iron agar. Although most isolates of the strain have uniform properties, some have slightly different antigens, antibiograms, phage types, or fermentation patterns. Most isolates have come from stools of infants under 1 year of age and are probably hospital acquired; however, other isolates are probably community acquired. Eighteen other lac+ Salmonella isolated in the United States were also studied. Most of these strains resembled E. coli on primary plates and triple sugar iron agar; thus their identification would pose a problem for most clinical laboratories. A simple procedure for detecting lac+ Salmonella mixed with lac+ E. coli consists of touching 12 colonies in succession with a straight wire and then inoculating a peptone iron agar tube. H2S production is apparent from lac+ Salmonella even if 11 E. coli and one Salmonella colony are picked. If a positive peptone iron agar tube is observed, then individual colonies are tested to rule out other strong H2S producers. The true incidence of lac+ Salmonella is unknown because they are not isolated and identified in most laboratories.

Antigens, Bacterial↗