Carbapenem Resistant Gram-Negative Organisms: Therapeutic Options In A Resource Limited Setting

Introduction: Health care associated infections due to carbapenem resistant gram-negative bacteria (CRGNB) are on the rise with limited available therapeutic options for these infections. Therapeutic options include newer drugs and drug combinations, which are not readily accessible in low resource. Older more affordable drugs have been reported to have good antimicrobial activity against some of these pathogens. This study aimed to determine the susceptibility profile of CRGNB isolates to the recommended, readily available and affordable, antibiotics in our setting.

Methods: This cross-sectional laboratory-based study was carried out from December 2017-August 2018. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii identified from inpatient specimens were subjected to susceptibility testing using the modified Kirby- Bauer technique. Carbapenem resistant isolates were further subjected to susceptibility tests against tigecycline, colistin, fosfomycin, polymyxin B, amikacin, and piperacillin-tazobactam. Breakpoints were read off using CLSI standards and appropriate controls.

Results: Of the 238 isolates studied, 18 (8.2%) showed resistance to ertapenem while 16 (6.7%) and 15 (6.3%) showed resistance to imipenem and meropenem respectively. Tigecycline, colistin, and polymyxin B showed impressive activity 94%, 88% and 83% activity against carbapenem resistant organisms respectively.

Conclusion: Tigecycline, colistin and polymyxin B are effective therapeutic options for treatment of infections caused by CRGNB. To optimize clinical improvement and reduce morbidity and mortality associated with these infections in resource poor countries, we recommend the use of tigecycline, colistin or polymyxin B for empirical treatment of infections caused by these pathogens.