Opening Pandora’s box: high level resistance to antibiotics of last resort in Gram negative bacteria from Nigeria

Objectives
To determine the percentage of drug resistant isolates and resistance mechanisms in Gram negative isolates from south western Nigeria.

Methods
A total of 306 non-duplicate unbiased Gram-negative isolates were recovered from patients admitted to three teaching hospitals in south western Nigeria in 2011 and 2013. Isolates were from clinical samples but also from stool of inpatients without infection to assess resistance patterns in carriage isolates. Susceptibility testing, PCR and sequencing were used to identify genes encoding various known beta-lactamases. Based on the phenotypic and genotypic results, 10 isolates were selected for whole genome sequencing to represent the diversity of phenotypes present.

Results
Susceptibility testing revealed 78.1%, 92.2% and 52.6% of all isolates were resistant to fluoroquinolones, third generation cephalosporins and carbapenems respectively. There were more resistant isolates from the stools of uninfected patients than from specimens of patients. E. coli (10%) and Klebsiella (7%) isolates produced a carbapenemase. Whole genome sequencing of selected isolates identified the presence of globally disseminated clones.

Conclusions
This depicts a crisis for the use of first line therapy in Nigerian patients, it is likely that Nigeria is playing a significant role in the spread of AMR due to her high population and mobility across the globe.