Evaluation of a PCR technique in blood samples of suspicious cas-es to systemic salmonella infections in Aliasghar children hospital, Tehran

Typhoid fever is still a major health problem for which there are limited options for the diagnosis. Current diagnostic methods are time consuming with undesirable sensitivity. Among newer diagnostic methods, PCR is attractive and could be potentially very helpful in developing countries where systemic salmonella infections are endemic among children but needs to be investigated.
We performed a cohort study in Aliasghar Children Hospital, a teaching hospital in Tehran, between May 2012 and July 2013 to include suspicious systemic salmonella infections. Clinical and laboratory findings as well as clinical courses were followed on daily basis. Overall, 45 patients assigned into 3 groups were included into the study. For each case all appropriate cultures as well as Widal agglutination test and a blood sample for PCR of salmonella were submitted after taking informed consent from parents.
Twenty one (46.7%) boys and 24 (53.3%) girls with ages ranging from 1 month of age to 17 years (mean 4.5 years) diagnosed for typhoid fever. About 88.9% of the patients had diarrhea, 84.4% had fever, 66.7% had vomiting, 28.9% had abdominal pain, 15.6% had nausea, 11.1% had rash and 2.2% had constipation. Eighteen (40%) patients have received antibiotic treatment before coming to the hospital. Group I consisted of 18(41%) patients, group II consisted of 27 patients with positive Widal test of these, one was blood and stool cultures positive however PCR in blood was negative in this group. Group III represented 2 patients with positive blood and stool cultures. In one case PCR in blood was positive. In another patient Widal test was negative despite positive blood culture and PCR in a leukemic kids who passed away.
In our setting the role of conventional PCR in blood samples of kids with suspicious systemic salmonella infections was not clearly determined. Larger sample size, preferably in a multicenter study, and using more sophisticated methods of blood cultures and novel techniques to increase the availability of organism for DNA detection is needed before determination of its role in both groups with no prior antibiotic therapy and cases with previous history of antibiotic administration.