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Live Salmonella typhi administered intraperitoneally, acetone-killed S. typhi administered intraperitoneally, and live S. typhi given orally, with their effectiveness decreasing in that order, protected Swiss white mice against death from challenge with a virulent Salmonella typhimurium hybrid expressing S. typhi antigens.
Between 1.1.1970 and 31.12.1973 3639 strains were typed with the aid of phage typing. Of these strains 1793 belonged to S. typhi and 1846 to S. parathyphi-B. 40 S. typhi phage types were found. 9 of these occurred in a frequency of more than 1% (relevant to foci). These were E1 (25.7%) (of this E1a 19.7%, E1b 5.9%), A (16.6%), F1 (7.5%), D1 (59%), C1 (5.4%) D2 (2.3%), 46 (2.1%), 28 (1.9%). Among S. paratyphi-B 24 phage types resp. varieties were found, 14 of these occurred in a frequency of more than 1% (relevant to foci). The phage types comprised Taunton (36.8%), 1 m.c. (10.3%), 3aI m.c. (7.5%), B.A.O.R. (6.8%), 3 a m.c. (4.9%), Dundee (4.6%), 3 aI var. 1 (4.6%), Beccles m.c. (2.4%), 3 b m.c. (2.3%), 3 aI var. (2%), 1 var. (1.8%), 3 aI var. 4 (1.1%). As far as it came to be known the epidemiological relations and particularities of the different S. typhi and S. paratyphi-B phage types are discussed. In th period of this report only one larger epidemic outbreak of S. paratyphi-B (type Taunton) occurred. Possibly the cause of this was contaminated milk.
BACKGROUND: As most Salmonella Typhi (S. Typhi) cases notified to public health units in Australia are acquired overseas, a case without recent travel raises concerns of local transmission. We describe a case of S. Typhi in a hospital inpatient without recent travel, where early use of genomic sequencing suggested remote acquisition from Chile in the 1980s, with chronic asymptomatic carriage. This facilitated the stand-down of a complex acquisition investigation. CASE: A notification of S. Typhi on stool culture was received for a female aged over 90 years living in Melbourne, Australia in October 2023. She had been hospitalised for three weeks (unrelated illness) and transferred into a residential aged care facility (RACF) six days prior to the result being known. She was asymptomatic and the sample was collected due to a recent ward gastroenteritis outbreak. INVESTIGATION: Epidemiological investigation identified the case had emigrated to Australia in 1981 from Chile. Recent typhoid-like illness, overseas travel or contact with travellers from endemic areas were excluded. Subsequent genomic sequencing identified the isolate was multilocus sequence type 2 and did not cluster with any strains isolated in Victorian or international databases, most closely clustering with historical South American strains, with potential in-host changes over time. MANAGEMENT: The case was presumed infectious throughout their hospital stay, with chronic carriage. There were 18 contacts, of whom 14 provided screening samples and were negative. Antibiotic case clearance was not recommended by the treating clinician due to patient comorbidity, treatment toxicity risks and unlikely treatment success without gallbladder removal. Enhanced infection control measures were instituted in the RACF (e.g. private bathroom, contact precautions for personal care, no food preparation). No additional cases were reported after two incubation periods (60 days). CONCLUSION: Early genomic sequencing enhanced the efficiency of the public health investigation by rapidly confirming overseas acquisition and chronic carriage, obviating the need for extensive local upstream investigation.
Lipopolysaccharides (LPS) of Salmonella typhi strains, isolated from carriers and patients suffering from typhoid fever, were characterised according to their biochemical properties, morphological structure and degree of aggregation of complexes. All preparations of LPS, regardless of their origin, were morphologically heterogeneous. Free electrophoresis and immunoelectrophoresis demonstrated that LPS preparations were composed of components possessing different mobilities in electric fields. LPS of bacterial strains isolated from both carriers and patients, split upon reaction in immunoelectrophoresis with specific antiserum 73, rabbit antiserum to Salmonella typhi Vi Bhatnagar and 0-901 split into anodic and cathodic fractions. The anodic fraction reacted similarly as Vi antigen. LPS from Salmonella typhi Ty-2 yielded only the cathodic fraction, typical for O antigen. LPS from strains which were passaged twice in nutritional medium possessed identical properties as LPS from fresh cultures of Salmonella typhi. Electron microscopy revealed that LPS appears as long bands, rods, ellipsoid forms and amorphous material. Contrary to amorphous material, the bands, rods and ellipsoid forms possessed three-layer structure.
Among 262 strains of Salmonella typhi from an epidemic outbreak of typhoid fever in Baden-Württemberg in 1974 2 strains were isolated which were tetracyclin resistant and showed no reactions with the Vi testphages T, D6 and VII whilst all other strains belonged to lysotype A, subtype Tananarive. It turned out that the Tc resistance in both strains was caused by a fi- R plasmid which could be transfered to other S. typhi strains, to E. coli K12, S. paratyphi B, S. java and S. typhi-murium as well as from Tc resistant E. coli K12 back to S. typhi. The Tc R plasmid introduced in S. typhi, lysotype A, caused specific restrictions of typing phages T, D6 and VII. Also, the transfer of the plasmids to strains of S. paratyphi B and S. typhi-murium resulted in restrictions of a number of typing phages. Both plasmids had identical patterns of restriction. In this pattern the Tc R plasmid differed from those described in the literature.
The recovery of Salmonella typhi from blood, rectal swab, urine, bone-marrow, and rose spots was compared in 62 patients with typhoid fever, most of whom had received some antibiotic therapy before presentation. S. typhi was isolated from culture of bone-marrow in 56 patients (90%); in contrast, S. typhi was recovered from blood in only 25 (40%), from stool in 23 (37%), and urine in 4 (7%). S. typhi was isolated from 24 (63%) of 38 patients who had rose-spot cultures. If culture sites had been limited to blood, stool, and urine, the bacteriological diagnosis would have been missed in 24 patients.
An Escherichia coli hybrid, F1061, expressing Salmonella typhi somatic antigens 9 and 12, and a derivative of this hybrid, E. coli hybrid WR3078, expressing the S. typhi Vi antigen in addition to somatic antigens 9 and 12, were compared with S. typhi Ty2 in experiments to test their ability, as live vaccines, to protect Swiss white mice against death from challenge with a mouse-virulent Salmonella typhimurium hybrid expressing the S. typhi antigens 9, 12, Vi, and d. When the live, vaccinating organisms were administered intraperitoneally, 87.5% of the mice immunized with S. typhi Ty2 survived challenge, as compared with 62.5% of those immunized with E. coli hybrid F1061 and 55% of those inoculated with E. coli hybrid WR3078. When live organisms were administered orally at a dose of 10(9), 67.5% of the mice immunized with S. typhi Ty2 survived challenge as compared with 47.5% of those immunized with E. coli hybrid F1061 and 40% of those administered E. coli hybrid WR3078. Thus, the protection conferred by E. coli hybrid F1061 expressing only the S. typhi somatic antigens, although significant in this system, was inferior to that conferred by S. typhi Ty2 and the addition of the S. typhi Vi antigen to this hybrid (creating E. coli hybrid WR3078) did not enhance that protection.
Sera prepared with two different strains of Salmonella typhi were analysed against all the soluble antigens isolated from S. typhi 0901, S. typhi Ty2 and S. typhi Vi. Agar-gel diffusion against individual sera showed that, in all the sera, antibodies were induced against somatic antigens and free proteins. Absorptions of the sera with polysaccharides, split from the somatic antigens, removed the antibodies induced against the polysaccharide and its proteinic carrier in most of the somatic antigens of S. typhi 0901. The antibodies left in the absorbed sera reacted against the proteinic moieties of more complex somatic antigens of S. typhi and against free proteins from all the analysed strains. Only the absorption with proteins removed all the precipitating antibodies from the sera. Moreover, in incomplete absorptions with proteins, the first antibodies removed are the antipolysaccharides, since antibodies are never induced against the haptenic polysaccharide but against somatic conjugates; in these the proteinic moiety eventually varies with every batch of bacteria. The sera exhausted of precipitins still agglutinate the bacteria, thus confirming the assumption that agglutinins and precipitins may be different antibodies.
The methylations of adenine in the sequence -GATC- and of the second cytosine in the sequence - [Formula: see text] - were studied in Salmonella typhimurium and in Salmonella typhi. The study was carried out by using endonucleases which restrict the plasmid pBR322 by cleavage at the sequences -GATC- (DpnI and MboI) and - [Formula: see text] - (EcoRII). The restriction patterns obtained for this plasmid isolated from transformed S. typhimurium and S. typhi were compared with those of pBR322 isolated from Escherichia coli K-12. In E. coli K-12, adenines at the sequence -GATC- and the second cytosines at - [Formula: see text] - are met hylated by enzymes coded for by the genes dam and dem, respectively. From comparison of the restriction patterns obtained, it is concluded that S. typhimurium and S. typhi contain genes responsible for deoxyribonucleic acid methylation equivalent to E. coli K-12 genes dam and dcm.
Two steps in the procedure for bacteriophage typing of Salmonella typhi have been automated. The culture inoculum was applied by flooding the surface of phage agar in a 150x20 mm petri dish and removing the excess liquid with a safety pipettor. This step replaced the older method of manually preparing up to 100 individual areas for inoculation. The number of bacteria per unit area was the same with both methods, so the automated method involved no change in the technique. The second automated step involved use of a bacteriophage applicator which simultaneously dispensed 59 uniform drops of bacteriophages onto the inoculated plate. The automated procedure has reduced personnel time by about 90% with no less in sensitivity or accuracy.
An immunogenic complex was isolated from Salmonella typhi-murium and another one from Salmonella typhi Ty2. Both were prepared by the bacterial acetone powder method which eliminated the cell wall, the DNA almost completely and the membrane phospholipids. The complexes were denominated "New Vaccines". The S. typhi-murium new vaccine induced, even at doses of 0.5 microgram dry weight per mouse, a high degree of protection against the challenge of the virulent microorganism. By immunoelectrophoresis, 21 antigen-antibody systems could be detected, two of them corresponding to O antigens. The S. typhi Ty2 new vaccine induced better protection than the standard vaccine (heat-phenol inactivated typhoid vaccine) when both vaccines were compared in the relative potency test. Moreover, the new vaccine had very low toxicity when inoculated in humans at doses of 1 microgram dry weight, able to elicite a high antibody titre (1/1,790 mean of 10 sera) in 75% of the tested population, estimated by the complement fixation test. In contrast, the standard vaccine induced a low antibody titre (1/222, mean of 5 sera) in 50% of the humans inoculated with 1 X 10(8) bacterial cells. The new vaccine did not induce undesirable effects whereas the standard vaccine induced an important inflammatory process in 100% of the cases, with intense local pain in 67% after 24 h post-first inoculation as well as other less severe symptoms.
The genetic transformation of Escherichia coli K-12 with chromosomal deoxyribonucleic acid purified from Salmonella typhi is described.
Himalayan rabbits of a closed colony were immunized with injections of heat-killed Salmonella typhi and antiidiotypic antibodies against the induced anti- S. typhi antibodies were produced in rabbits of the same colony as well as in random-bred rabbits. Rabbits of the closed colony showed no proliferative response in a mixed lymphocyte culture of peripheral blood. Antiidiotypic sera from Himalayan rabbits recognized the idiotype in the corresponding immunizing sera alone, while one of sera from random-bred rabbits showed a cross-reaction with 8 out of 10 anti-S. typhi sera of Himalayan rabbits but not with any of 10 anti-S. typhi sera of unrelated random-bred rabbits. The cross-reactivity of the antiserum remained intact after absorption with unrelated immune precipitates. With this antiidiotypic serum the immunizing serum formed a bimodial arc at beta-gamma mobility and all other anti-S. typhi sera containing the cross-reactive idiotype a single arc at beta mobility. Solubilized immune precipitates of cross-reactive idiotype-anti-idiotype reaction could bind radiolabelled lipopolysaccharide (LPS) from S. typhi, but this anti-LPS activity was not revealed in an isoelectric focusing analysis. Gel analysis showed that the cross-reactive idiotype was located mainly in the macroglobulin fractions. The idiotype in the serum of the immunizing rabbits diminished and then was undetectable following the 2nd and the 3rd immunizations. When 3H-TdR uptake was examined in a mixed cell culture of peripheral blood from immunizing and antiidiotypic rabbits, there was a fluctuation in the proliferative response with two peaks occurring at a 4-week interval. An analysis of such a proliferative response was carried out by separating leukocytes and plasma from blood of the immunizing and the antiidiotypic rabbits. Mixed culture of cells alone did not produce a proliferative response, while culture of cells from the immunizing rabbit together with antiidiotypic plasma resulted in a potent reaction, irrespective of the presence of plasma from the immunizing rabbit. Presence of cells from the antiidiotypic rabbit in the culture inhibited this proliferative response. A fluctuation in the proliferative response to antiidiotypic serum was also observed with peripheral blood leukocytes (PBL) from rabbits producing the cross-reactive idiotype, while the antiidiotypic serum did not stimulate cells from rabbits which had been similarly immunized with S. typhi but did not produce the idiotype. PBL from the immunizing rabbit where the idiotype production ceased following the tertiary immunization were found to suppress definitely the proliferative response induced by the cross-reactive idiotype-anti-idiotype reaction. The suppressive activity was lost in PBL from the same rabbit after a cortisone treatment and the following antigenic stimulation of the animal led to reappearance in the serum of the idiotype. These results support the immune regulatory model which involves idiotype-anti-idiotype interactions.
Artificial contamination of young lettuce plants with Salmonella typhi (ST), Escherichia coli (EC), and Enterobacter aerogenes (EA) in the field in winter and summer resulted in presence of the pathogen and increased density of the two indicator bacteria (IB) in harvested produce. Viable counts of the three bacteria/g fresh weight declined at a decreasing rate with increasing time after contamination. The overall pattern of variation of the ST/IB ratio was correlated more closely with changes in the ST/EA than in the ST/EC ratio values. When viable counts were expressed as a proportion of the contaminating dose at different times after contamination, however, a closer similarity existed between ST and EC than between ST and EA values throughout winter and through the early part of summer experiments.
An Asian patient with undiagnosed typhoid fever was admitted to a maternity hospital and delivered within 10 min. Salmonella typhi (phage type D5) was isolated from her blood and from the faeces of her baby. Another women in a different room of the labour suite at the same time acquired the same organism in her faeces; her brother was admitted to the Infectious Diseases Unit 5 weeks later with typhoid fever. Two babies, born over 60 h after the index case was delivered, became faecal excreters of the same strain and one of them also developed S. typhi osteitis of the hip. These two babies and their mothers were in the same ward as each other, but not that occupied by the infected mother and her baby. Nine other excreters in two of the families involved were identified. The index case and her baby were isolated immediately after delivery, and the relevant rooms in the labour suite were adequately disinfected. No evidence of undisinfected equipment used by the index case and the other infected patients was found, and no spread to staff was detected. The mode of spread remains unknown.
Bacteriologically proved cases of salmonellosis presenting at the University Hospital have increased nearly threefold since 1957. The most striking change has been a considerable increase in the incidence of Salmonella heidelberg and Salmonella derby in the last 5 years, probably resulting from hospital acquired infection. About 80 cases of typhoid fever are reported each year in Jamaica. There has been little change in the prevalence of different phage types of Salmonella typhi since 1961. Paratyphoid fever is rare. Standardized antimicrobial disk-sensitivity testing was performed on selected surviving salmonella strains since 1964. S. typhi has remained fully sensitive to all the agents tested except streptomycin. Other salmonellas, however have shown a significant increase in antimicrobial resistance since 1970. Most of this increase was due to multiple resistance in S. heidelberg and S. derby, and the survival and dissemination of these strains in the hospital environment may be related to antibiotic usage.
The double-immunodiffusion technique and sodium dodecyl sulfate-polyacrylamide electrophoresis were used to demonstrate the presence of flagellin-like material strongly attached to ribosomes of Salmonella typhi Ty 2. This flagellin-like material contaminating the ribosome preparation interferes with the induction of antiribosome serum promoting the formation of antisera reacting either only with flagellin or in some cases with flagellin and ribosomes, but giving a very weak reaction with the latter. The interference is also observed when purified ribosomes from a nonflagellated mutant of S. typhi (S. typhi O-901) mixed with purified S. typhi Ty 2 flagellin are utilized as antigens. The antiribosome sera obtained with ribosomes from S. typhi O-901 have a considerably higher titer than those that are interfered with. These sera were able to react with ribosomes obtained from several related species and did not react with flagella-derived flagellin of S. typhi Ty 2.
In 21 persons with previous typhoid fever and in 15 controls thymidine incorporation of blood lymphocytes stimulated in vitro by killed Salmonella typhi was studied. The optimal culture conditions were established to be a cell density of 10(5) cells per vial, stimulated with 10(8) S. typhi and incubated for 5 days. The lymphocytes response to S. typhi was significantly higher in the typhoid group than in the controls. The lymphocyte responsiveness was not correlated to the time elapsed since the attack, and was not found different in patients who had had typhoid relapse. No difference was found in lymphocyte response to the mitogens PHA, PWM and Con-A between the typhoid group and the controls.