Salmonella Enterica Serovar Paratyphi A Carrying the CTX-m Gene Sepsis

We report a case of a 9-year old girl who presented with fever, recurrent gastrointestinal disturbances, and consequent dehydration, after a visit to Pakistan 3 months previously.

From her blood culture, Salmonella Enterica serovar paratyphi A was isolated, carrying the CTX-m gene and demonstrating resistance to amoxicillin, co-amoxiclav, pipericillin+tazobactam, ceftazidime, cefepime, cefotaxime, tobramycin, ciprofloxacin and tigecyclin.

This is the first case of its kind in the UK, underlining a worrying trend both toward higher proportions of enteric fever caused by S. paratyphi (an organism for which no vaccine is available), and toward increasing loss of antimicrobial effectiveness against the organism in South Asia and elsewhere. This is the first organism of its kind in the UK to be found to be resistant to all cephalosporins and narrower-spectrum beta lactamases such as amoxicillin. Further typing revealed that production of cephalosporinases by this organism contributed to this.

As geographical context typically provides the predicted bacterial sensitivities, which in turn permit our empiric antibiotic treatment (while we await lab-confirmed cultures), our empiric antibiotic selection in these cases must appropriately reflect these resistance patterns. Moreover, they starkly illustrate our vital need for appropriate antibiotic stewardship now and in the future, to preserve our ability to treat the potentially-fatal condition.

As an additional point of interest, we have identified in this case the co-existence of entamoeba histolytica species with this S. paratyphi, which we believe may be the first such finding documented in the literature. Further study is required to elucidate their pathophysiological relationship and its effects on the clinical picture.