55
A standardised Vi anti-serum has also been issued to all laboratories. By
the use of this serum comparisons can be made with results obtained, and the
type of agglutination. that should be obtained in positive cases appreciated.
Isolation of Enteric Group organisms from blood culture.— A total f 4020
blood cultures were taken during the year from cases suspected to be suffering
from enteric group infection. The following is a summary of successful isola-
tions. B. typhosum 72, B. paratyphosum A. 29, B. paratyphosum B. 2, and
B. Paratyphoid C. 1. The average day f isolation was as last year the 5th
day after onset of the disease.
Of the total cultures 16 per cent. were found to be contaminated which is a
great reduction compared with some years ago but slightly higher than last
year.
In one Laboratory in which contaminations were high investigations were
carried out concerning the possibility f the addition of a weak solution of
gentian violet to the taurocholate broth. Preliminary tests were first made to
ascertain the optimum dilution, which would entirely or almost entirely inhibit
the Gram positive cocci, and at the same time not prevent free growth of the
Gram negative bacilli. A dilution of 1—16,000 was eventually found to be the
most suitable.
Media containing gentian violet in the above dilution was then issued to
selected hospitals and the results obtained were most gratifying.
A r e v i e w o f t h e r e s u l t s s h o we d t h a t wi t h o r d i n a r y t a u r o c h o l a t e me d i u m
contaminations amounted to 19 . 4 per cent. whereas the substitution Òf gen-
- t i a n v i o l e n t m e d i u m d e c r e a s e d t h e p e r c e n t a g e t o 5 . 5 .
Duplicate bottles of media were employed in taking all blood cultures in
one large British Military Hospital. In no case were organisms isolated from
the plain broth while the other remained sterile, though in one case the organ
ism was isolated from the gentian violet medium while the plain broth re-
mained sterile.
The apparent advantage of this method of blood culture has been brought
to the notice f all officer commanding laboratories in India and it will be
interesting to see the figure representing percentage of contaminations in next
year's report.
Isolation of Enteric GrÒup organisms from faeces and urine. —The isolations
of enteric group bacilli from faeces were 61 (B. typhosum 40, B. paratyphosum
A. 18, B. paratyphostirn B. 2, and. B. paratyphosum C. 1). This figure is
small in view of the fact that there was a total of 148 isolations from blood
culture. Attention however is drawn to the opinion expressed in last year's
report that apart from any question of defective technique in the collection
of specimens in hospitals for despatch to Laboratories, it is probable that in a
heavily inoculated individual isolations may be more difficult than in the case
of the uninocuiated.
All British troops diagnosed Enteric Group of infection during the year
were automatically sent to the Enteric Fever Convalescent Depot Kasauli
for examination concerning a carrier condition. In no case was any pathological
organism isolated from any of these convalescents.
Organisms of the Enteric Group were isolated from the urine of patients
on eighty-nine occasions. Some of the cases of Typhoid and Paratyphoid in-
fection exhibited unusual features and are worthy of special mention.