Chander, Jagdish

Gupta, Varsha

Kumar, Rohit

Singhal, Lipika

Singla, Nidhi

Tejan, Nidhi

English

Atharva Scientific Publications (E-Jounals)

Gupta et al                                Antibiotic susceptibility pattern of S. Typhi 
Vol 1 / Issue 1 / Jul – Sep 2016                                                                  Eastern J Med Sci / 40 
Letter to Editor 
Monitoring of antibiotic susceptibility pattern of blood isolates of 
Salmonella enterica var Typhi from a tertiary care hospital in North India 
Varsha Gupta, Lipika Singhal, Nidhi Tejan, Nidhi Singla, Rohit Kumar, Jagdish Chander  
From, the Department of Microbiology, Government Medical College and Hospital, Sector 32, Chandigarh India 
Correspondence to: Dr. Varsha Gupta, Department of Microbiology, Government Medical College and Hospital, Sector 32, 
Chandigarh. Email - varshagupta_99@yahoo.com.  
Received: 20 August 2016  Initial Review: 30 August 2016     Accepted: 07 September 2016    Published Online: 19 September 2016 
Sir, 
Enteric fever carries a significant morbidity and mortality. 
Antibiotic therapy constitutes the mainstay of its 
management. However, failure to treat it properly leads to 
prolonged illness, development of a carrier state and 
increased dissemination [1]. Considering the changing 
trends in the susceptibility patterns as re-emergence of 
susceptibility to conventional first-line antibiotics, reduced 
susceptibility towards ciprofloxacin, emergence of 
Salmonella enterica var Typhi (S. Typhi) resistant to third-
generation cephalosporins, continual monitoring of drug 
resistance patterns is vital [1-3].
  
A total of 192 non-repeat S. Typhi isolates obtained 
from conventional blood cultures performed for routine 
bacterial culture sensitivity between January 2011 and 
December 2014 were included in the study. The 
identification of S. Typhi was done by the colony 
morphology and standard biochemical tests. They were 
confirmed by serotyping. Antibiotic susceptibility testing 
was done by Kirby Bauer’s disk diffusion method 
according to CLSI 2015 guidelines [4] using commercially 
available disks (Hi-media Laboratories, India). Also 
minimum inhibitory concentration (MIC) of ciprofloxacin, 
chloramphenicol and ceftriaxone was determined by agar 
dilution and E-Test (Biomerieux) for all the isolates.  
A high susceptibility of >99% was observed for the 
first-line antibiotics-chloramphenicol and co-trimoxazole. 
All the isolates (100%) were susceptible to 
chloramphenicol with a MIC of ≤ 8µg/ml both by agar  
 
dilution test and E-test method with the MIC50 being 1 
µg/ml. This observation has therapeutic implication since 
these drugs could once again be used for the treatment of 
typhoid fever, but treatment should be carefully monitored 
for side effects.  
Conversely, our study documents high resistance to 
ampicillin which is in contrast to recent studies from 
adjoining and different parts of India [2].
 
Resistance to 
nalidixic acid was found to be highest (100%) amongst all 
the antibiotics. For ciprofloxacin, majority of the S. Typhi 
isolates were in the intermediate susceptibility zone. This 
corroborated well with the MIC results whereby, majority 
of the S. Typhi were in the intermediate MIC range (0.125-
0.5 µg/ml-revised breakpoints). This may aid in better 
depicting the ciprofloxacin susceptibility at places where 
MIC determination is not accessible. The highest recorded 
MIC was 32µg/ml for S. Typhi, which is in the resistant 
MIC range (≥1µg/ml). High rate of susceptibility was seen 
towards azithromycin (100%) which is an orally effective 
drug using the newly suggested zone criteria by CLSI [4].  
Azithromycin seems to be an effective therapeutic 
option; however, MIC determination would be necessary 
to understand its effectiveness in view of non-uniform 
susceptibility pattern noticed in various studies. [2,5,] 
Third generation cephalosporins remain the drug of choice 
with high susceptibility to cefotaxime and ceftriaxone. All 
the isolates had MIC (≤1 µg/ml) for ceftriaxone by both 
agar dilution and E-Test. Judicious use is mandatory to 
prevent emergence of resistant strains. 
Gupta et al                                Antibiotic susceptibility pattern of S. Typhi 
Vol 1 / Issue 1 / Jul – Sep 2016                                                                  Eastern J Med Sci / 41 
REFERENCES 
1. Gupta V, Kaur J, Chander J. An increase in enteric fever 
cases due to Salmonella Paratyphi A in & around 
Chandigarh. Indian J Med Res. 2009;129:95-8. 
2. Singhal L, Gupta PK, Kale P, Gautam V, Ray P. Trends in 
antimicrobial susceptibility of Salmonella Typhi from 
North India (2001-2012). Indian J Med Microbiol. 
2014;32(2):149-52. 
3. Capoor MR, Nair D, Hasan AS, Aggarwal P, Gupta B. 
Typhoid fever: narrowing therapeutic options in India. 
Southeast Asian J Trop Med Public Health. 2006;37: 
1170-4. 
4. Performance standards for antimicrobial susceptibility 
testing; Twenty-fifth Informational Supplement. Clinical 
and Laboratory Standards Institute (CLSI) Wayne, PA; 
2015. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5. Rai S, Jain S, Prasad KN, Ghoshal U, Dhole TN. Rationale 
of azithromycin prescribing practices for enteric fever in 
India. Indian J Med Microbiol. 2012; 30(1):30-3. 
 
 
 
 
 
 
 
 
How to cite this article: Gupta V, Singhal L, Tejan N, 
Singla N, Kumar R, Chander J. Monitoring of antibiotic 
susceptibility pattern of blood isolates of Salmonella 
enterica var Typhi from a tertiary care hospital in North 
India Eastern J Med Sci. 2016; 1(1): 40-41. 
Conflict of interest: None stated, Funding: Nil 


Monitoring of antibiotic susceptibility pattern of blood isolates of Salmonella enterica var Typhi from a tertiary care hospital in North India

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Monitoring of antibiotic susceptibility pattern of blood isolates of Salmonella enterica var Typhi from a tertiary care hospital in North India

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