The use of phage-sensitivity patterns for tracing heat labile toxin-positive (LT+) Escherichia coli.

The heat-labile toxin (LT) positive Escherichia coli colonies from 785 stool specimens obtained during a cholera vaccine trial were examined for their phage-sensitivity pattern to 31 E. coli phages. These specimens originated from 105 index cases and their contacts. Isolates with common phage-sensitivity patterns were grouped and were studied further both serologically and for their plasmid profile. The largest group (42 isolates) belonged to serogroup O78 and the second largest group (19 isolates) belonged to serogroup O6. There were 23 index cases which had E. coli with the same phage-sensitivity pattern as some of their contact strains. The identity of isolates from 16 index cases with strains from their respective contacts could be verified serologically. For the remaining seven index cases and their contacts, the isolates did not agglutinate with available antisera. However, subsequent studies demonstrated that, when the phage-sensitivity pattern among the strains matched, the plasmid profiles of these strains also matched. This further indicates the ability of phage-sensitivity patterns to serve as markers in tracing strains.

First isolation of Yersinia intermedia from stool during an epidemiological investigation in Bangladesh.

Following the first isolation of Yersinia intermedia (Y. intermedia) in the Microbiology Branch of ICDDR, B from two postmortem cases, one of whom suffered from pneumonia and septicaemia and the other from enteric fever, an epidemiological investigation was carried out in the communities from where these postmortem cases had come. The stools from both postmortem cases were negative for Yersinia. One hundred and twenty five contacts of the first postmortem case and 135 contacts of the second postmortem case along with 175 animals of Dhaka Zoo were examined. Y. intermedia was isolated from only a five-year-old healthy contact of the first postmortem case. This was the first isolation of Y. intermedia from stool of a healthy child in Bangladesh.

Comparative behaviour of classical and El Tor biotypes of Vibrio cholerae 01 isolated in Bangladesh during 1982.

PIP: The change from classical to the El Tor biotype of Vibrio cholerae during the early seventies in Bangladesh remains to be elucidated. The shift in 1982 from El Tor back to the classical was not predicted, but provided an opportunity to study both the biotypes occurring simultaneously in nature, compared with earlier isolates. Comparative studies showed TCBS to be as good as TTGA for isolation of the 2 biotypes. Replacement of the El Tor by the classical biotype as the dominant epidemic strain, occurred over 4 months. Isolates of both biotypes from 1982 were found to be slow in mannitol fermentation. The isolates of El Tor were frankly haemolytic and belonged to phage type 4. The classical strains were of phage type 3. V. cholerae strains isolated in the late sixties and early seventies were similar in these markers. This suggested that the epidemic was caused by strains indigenous to Bangladesh. A classical strain of V. cholerae isolated in 1969 was overgrown by an El Tor strain of the same year when grown together in peptone water. Classical strains of 1982, however, grew competitively with 1969 and 1982 strains of El Tor. 1 classical isolate of 1982 survived for 50 days when grown with an El Tor strain of 1969. These findings suggest that the classical V. cholerae strains of 1982 successfully compete with the El Tor strain. They are more toxigenic than the prevailing El Tor biotype.^ieng

Evaluation of two intravenous rehydration solutions in cholera and non-cholera diarrhoea.

A clinical trial was carried out with 126 male patients over 2 years of age suffering from diarrhoea requiring intravenous rehydration, 80 of the patients suffering from cholera and 46 from non-cholera diarrhoea. A new "diarrhoea treatment solution" (DTS) containing sodium at a concentration of 118 mmol/litre and glucose at 44 mmol/litre was compared with the usual Dacca intravenous solution (DS) which has a sodium concentration of 133 mmol/litre and contains no glucose. The other constituents and their concentrations were the same in both solutions. All the patients responded well clinically and made an uneventful recovery. Oral water intake measured during the first 24 h was higher in the group receiving the DS. This group also excreted a significantly higher quantity of sodium in the urine. A significant fall in the level of blood glucose from the admission values occurred in both the groups; the fall was relatively less in the DTS group, this solution containing 44 mmol of glucose per litre. Further work is required to find the optimum concentration of glucose in the solution for infants and young children.

Adhesion of cholera phage to glass surfaces at high inactivation temperatures.

Decimal dilutions of cholera phage heated in test tubes at the temperature range of 65 degrees to 70 degrees showed an erratic behaviour in that the residual counts had no relationship to the quantity of phage originally present in the tubes. If the contents of the heated tubes were decanted off and the empty tubes washed repeatedly with broth, the recovery of phage from successive washings of the tubes was much higher than what would be expected on the basis of the simple dilution effect of washings. The data presented indicate that the heating causes loose adhesion of phage to the wall of the glass tubes from where they can be detached by washing or shaking. The facts that E. coli phage T1 and also cholera phages tested with two different broths have given similar results, suggest that some general property of the phage itself is responsible for the phenomenon observed. The phenomenon appears to be different from the adsorption of phage to glass filters at lower temperature range described by earlier workers.

Thermal inactivation of cholera phages.

Thermal inactivation of seven cholera phages have been tested over the temperature range between 50 degrees to 70 degrees C. It was found that the phages vary widely in their heat sensitivity, Mukerjee's phages III being the most sensitive of the whole group. With all the phages over the temperature range studies, the inactivation curve seem to follow the pattern of virus thermal inactivation in general, the inactivation proceeding initially at a rapid rate, which in about 15 minutes time, gradually changes to a slower rate, each component tending to follow kinetics of the first order. The difficulty of explaining this phenomenon on the basis of population heterogeneity has been discussed.

Treatment of variola major with cytosine arabinoside.

A controlled study of the efficacy of cytosine arabinoside in the treatment of patients with variola major was performed. Cytosine aravinoside was given intravenously at a dose approximating 3 mg/kg of body weight every 24 hr for up to seven days. All nine patients receiving cytosine arabinoside and four of the 11 patients receiving placebo died. In three of the patients receiving cytosine aravinoside, death occurred late in the illness at a time when the patient's lesions began to dry up, the patient's temperature became normal, and the patient's general condition appeared to improve. The virus could be isolated from the blood at day 7 from three of four patients treated with cytosine arabinoside as compared with zero of six control patients. Hematologic data showed a depression in the number of circulating granulocytes. It is possible that the drug lowered the resistance to infection either through direct suppression of granulocytes or through interference with other immune mechanisms. Cytosine arabinside administered in the doses used in this study is not effective in the treatment of variola major.

Treatment of variola major with adenine arabinoside.

A double-blind study of the efficacy of adenine arabinoside in the treatment of patients with variola major was conducted. Adenine arabinoside (20 mg/kg of body weight) was given to patients intravenously every 24 hr for seven days in a 8-hr infusion. Five of the nine patients receiving adinine arabinoside died, and four of 11 patients receiving placebo died. Mortality was related to the severity of illness for both groups of patients. No difference was found between the drug and control groups in number of febrile days after initiation of therapy or in the period during which it was possible to isolate virus from skin lisions, throat swabs, and sources of clotted blood. Formation of scabs on skin lesions was complete 8.3 days after the initiation of therapy for the drug group and after 11.3 days for the control group. The findings suggest that adenine arabinoside is not effective in the chemotherapy of smallpox.

Clinical studies of the use of bacteriophage in the treatment of cholera.

This study reports the use of bacteriophage prepared in the USSR in the treatment of cholera. Patients with acute cholera were rehydrated with a standard intravenous solution and were then given a bacteriophage preparation in addition to maintenance intravenous therapy. The titre of the phage preparations was between 10(8) and 10(9) pfu/ml. Bacteriophage was given by mouth (25 ml for adults and 20 ml for children) for 3 days; in addition, some patients were also given an intramuscular injection (20 ml) of phage on the first day in hospital. For comparison, other groups of patients were given a standard tetracycline regimen or a placebo preparation. Daily vibrio and phage counts were made on stool samples from all patients and the vibrio strains isolated from each patient were tested for sensitivity to the phage preparation.The criteria used to evaluate the various therapies were duration of diarrhoea, volume of stool, and duration of vibrio excretion.The results of the study demonstrate that, in the doses used, the therapeutic effect of bacteriophage, if any, was markedly inferior to that of tetracycline and that in the current state of our knowledge bacteriophage, as used in this study, has no place in the treatment of cholera.

Effect of massive doses of bacteriophage on excretion of vibrios, duration of diarrhoea and output of stools in acute cases of cholera.

Each member of a group of 8 patients with acute cholera was treated with a mixture of four cholera bacteriophage preparations containing over 2 x 10(12) phage particles/ml. These massive doses were intended to kill immediately all vibrios in the intestine by "lysis from without". The numbers of Vibrio cholerae were drastically reduced rapidly. In 4 patients, V. cholerae was completely eliminated from the stools early in the treatment; the total stool volume and after-treatment of diarrhoea were reduced in comparison with a control group but were higher than in a group of patients treated with tetracycline. In the other 4 patients treated with phage, vibrios disappeard more slowly from the stools and there was no apparent clinical effect of the phage. In all the patients treated with phage, the duration of diarrhoea was longer than in patients in a control group who excreted vibrios for a similar length of time although the stool output was similar. This was interpreted as being due to the persistence of vibrios in foci of infection in the upper intestine.It is concluded that treatment of cholera with massive doses of bacteriophage is not as effective as treatment with tetracycline. However, phage can selectively eliminate the majority of vibrios without affecting the other intestinal flora and without any apparent toxic effect on the patient. Phage might therefore be useful as a research tool.