Hospital-acquired infections due to carbapenem-resistant Providencia stuartii

BACKGROUND & OBJECTIVES: During the course of a retrospective survey on healthcare associated infections (HAIs) due to carbapenem-resistant organisms, an unusual prevalence of HAIs due to carbapenem-resistant Providencia stuartii (CRPS) was found. Hence this study aimed to conduct the occurrence of P. stuartii associated HAIs with special reference to the drug resistance profiling of these isolates. METHODS: Of the eight total HAI cases (7.5% of total HAIs and 33.3% of HAIs due to Enterobacterales) of CRPS infections included in this study, three were reported from ventilator-associated pneumonia (VAP), three were surgical site infections (SSIs), one was a catheter-associated urinary tract infection (CAUTI) and one was a bloodstream infection. All the eight CRPS isolates were tested for extended-spectrum β-lactamases production, AmpC hyperproduction as well as carbapenem resistance. Typing of the isolates was performed by repetitive extragenic palindromic polymerase chain reaction (REP-PCR). RESULTS: All the eight isolates of CRPS were found to be AmpC hyperproducers, carbapenemase producers, and harboured chromosomally located bla(NDM) in seven isolates and bla(IMP) genes in one. All the cases with CRPS infections had prior history of colistin therapy along with prolonged hospital stay (>20 days). The cases were located in five different wards/intensive care unit (ICU) within the hospital in one year. However, strain typing by REP-PCR revealed 100 per cent similarity and clonal relatedness in all the seven isolates carrying bla(NDM) genes. Interestingly, routine hospital surveillance revealed a high carriage of P. stuartii in the axilla of patients admitted to the ICU. INTERPRETATION & CONCLUSIONS: The study findings suggest CRPS as an important cause of HAIs. This organism often goes unnoticed due to the burden of carbapenem resistance in other Enterobacterales and non-fermenters.