Table 2.

The frequency of association between different β-lactamase classes and resistance to ceftazidime–avibactam and ceftolozane–tazobactam among 75 MDR-P. aeruginosa isolates collected from Hamad Medical Corporation between 2014–2017.

Antibiotic	β-Lactamase Class	Resistant	Susceptible	p-Value *
		N = 37	N = 38
Ceftazidime–avibactam	Class A	48.6%	31.6%	0.131
	Class B	54.1%	0%	<0.001
	Class C	100%	92.1%	0.240 †
	Class D	91.9%	100%	0.115 †
Ceftolozane–tazobactam		N = 40	N = 35
	Class A	55%	22.9%	0.005
	Class B	50%	0%	<0.001
	Class C	95%	97.1%	0.99 †
	Class D	92.5%	100%	0.243 †

* p-value was calculated using Pearson Chi-Square test, ^† p-value was calculated using Fisher Exact test.