Prevalence and trends in the antimicrobial susceptibility pattern of Salmonella enterica serovars Typhi and Paratyphi A among children in a pediatric tertiary care hospital in South India over a period of ten years: a retrospective study

Abstract

The aim of this study was to determine the prevalence and trends in the antimicrobial resistance of typhoidal salmonellae in children and adolescents at a pediatric tertiary care hospital in South India. Typhoidal salmonellae were isolated from 483 of the 77,713 blood cultures received during the ten-year study period (2007-2016). Isolates were speciated by conventional biochemical reactions and serotyping. Antimicrobial susceptibility testing was performed and interpreted according to the British Society for Antimicrobial Chemotherapy (BSAC)/European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The overall blood culture isolation rates of Salmonella enterica serovars Typhi and Paratyphi A in children were 0.5% (408 cases) and 0.1% (73 cases), respectively, with the highest isolation rates in school [299 (61.9%)] and preschool children [113 (23.4%)]. A decreasing prevalence of enteric fever was seen from 2012 to 2015, with a sudden surge in 2016. From 2011 onwards, a high fluoroquinolone resistance (90-100%) was observed. Multidrug resistance was observed in only four (0.9%) S. Typhi isolates. 100% susceptibility to third-generation cephalosporins and azithromycin was noted. Enteric fever as seen in a pediatric tertiary care hospital in India affects children and adolescents of all age groups, with greater isolation rates in school children, followed by those in preschool years, calling for targeted interventions against these age groups. The study findings support the use of third-generation cephalosporins and azithromycin as first-line therapy and ampicillin and co-trimoxazole as step-down therapy in pediatric enteric fever. However, continued local surveillance should be done to detect antimicrobial resistance trends to optimize treatment.

Pediatric Blood Cultures and Antibiotic Resistance: An Overview

“…The decline in the ACCo resistance could be attributed to limited use of these antibiotics due to the availability of better alternatives like 3rd generation cephalosporins. On the other hand, there has been an increasing trend of resistance to quinolones in Salmonella and now almost 90-100% quinolone resistance in S. typhi & Paratyphi A has been reported especially after British Society of Antimicrobial & Chemotherapy (BSAC) revised its breakpoint guidelines in the year 2011 [20]. At authors' center, they have also observed a high resistance to quinolones (96%) and nil resistance to ceftriaxone in the pediatric population during the years 2014-2018.…”

“…In a study by Iyer et al, the prevalence of enteric fever at a pediatric tertiary care hospital from South India during the tenyear study period from 2007 to 2016, was found to be 0.5% and 0.1% for S. typhi and S. paratyphi A, respectively [20]. On the other hand, in a systematic review and meta-analysis in adults and children in India, a prevalence of 9.7% of S. typhi and 0.9% of S. paratyphi A was observed [21].…”

“…MDR in Salmonella is estimated to vary between 1.9% to 4.1% [20][21][22]. Multiple reports from all over India have also shown improved susceptibility to ampicillin, co-trimoxazole, and chloramphenicol (ACCo) [20,22]. Similarly, at authors' center too they noted a low ACCo resistance of 2.3% [22].…”

“…However, few cases of ceftriaxone resistance have been reported from Bangladesh, Nepal, United Arab Emirates and Germany [23][24][25][26]; therefore a strict vigilance on the emergence of ceftriaxone resistance in salmonella needs to be maintained. Azithromycin is recommended as an alternative therapy to ceftriaxone in the case of resistance to quinolones as per WHO guidelines and the current scarce literature on azithromycin shows little resistance to this drug [20,27]. Therefore, nowadays, ceftriaxone and azithromycin remain the drugs of choice for the empiric treatment of enteric fever although treatment may be modified based on susceptibility report of the isolates.…”

Salmonella enterica Serovar Typhi in Bangladesh: Exploration of Genomic Diversity and Antimicrobial Resistance

“…Ciprofloxacin (cip) resistance first emerged in the early 1990s. At present, over 90% of clinical isolates from regions of endemicity show reduced susceptibility to ciprofloxacin ( 6 , 7 , 11 ). These events shifted the first-line and empirical treatments to other classes of antimicrobial agents, such as ceftriaxone (cro) and azithromycin.…”