Uncommon non-fermentative gram-negative superbugs - A surge in bacteraemia patients at an apex super speciality hospital

BACKGROUND AND OBJECTIVES: Gram negative bacteria are most common cause of bacteraemia, with one fourth being attributed to non-fermentive Gram negative bacteria (NFGNB). Contribution of NFGNB to antimicrobial resistance burden is also high. Commonly isolated NFGNB Pseudomonas aeruginosa and Acinetobacter baumannii have been well studied however there is paucity of data of uncommon species including, Stenotrophomonas maltophilia, Burkholderia spp., Sphingomonas paucimobilis in our region. This study was thus designed to explore implication of antimicrobial resistance and associated determinants for the surge of such organisms. MATERIAL AND METHODS: Antimicrobial susceptibility profile of NFGNB isolates, recovered from flag positive blood culture bottles on BacT/ALERT3D system, identified by VITEK 2 compact system, over a period of one year at the department of Microbiology and risk factors associated with upsurge of common and uncommon NFGNB were also compared. RESULTS: A total of 133 NFGNB isolates were recovered from bacteraemia patients. Among common NFGNB, Acinetobacter baumannii (34.6 %) was commonest followed by Pseudomonas aeruginosa (15 %). While among uncommon NFGNB Acinetobacter non baumannii spp. of Acinetobacter baumannii complex were most prevalent (15 %) followed by Burkholderia cepacia complex (10.5 %) and Sphingomonas paucimobilis (8.2 %). Eighty percent of isolates were MDR and association of uncommon NFGNB surge was observed to be associated with risk factors like hospital acquired infection, recent broad spectrum antimicrobial exposure, primary bacteraemia and catheter related infection (p < 0.05). CONCLUSION: Bacteraemia due to MDR NFGNB is an alarming therapeutic management challenge as empirical treatment is not effective especially for uncommon NFGNB.