Table 4.

Antimicrobial resistance of the isolates responsible for non-invasive pneumococcal pneumonia in adult patients in Portugal, 2016–2018.

	No. of resistant isolates (%) a
	18–49 years (n = 246)	50–64 years (n = 322)	≥65 years (n = 581)
PEN	44 (17.9)	54 (16.8)	113 (19.4)
${\text{MIC}}_{90}^{\text{b}}$	0.38	0.25	0.38
${\text{MIC}}_{50}^{\text{b}}$	0.012	0.012	0.016
CTX	3 (1.2)	1 (0.3)	7 (1.2)
${\text{MIC}}_{90}^{\text{b}}$	0.25	0.19	0.38
${\text{MIC}}_{50}^{\text{b}}$	0.016	0.016	0.016
LEV	1 (0.4)	1 (0.3)	9 (1.5)
ERY	60 (24.4)	69 (21.4)	114 (19.6)
CLI	52 (21.1)	60 (18.6)	92 (15.8)
CHL	1 (0.4)	4 (1.2)	7 (1.2)
SXT	45 (18.3)	42 (13.0)	93 (16.0)
TET	53 (21.5)	65 (20.2)	104 (17.9)

^aPEN, penicillin; CTX, cefotaxime; LEV, levofloxacin; ERY, erythromycin; CLI, clindamycin; CHL, chloramphenicol; SXT, trimethoprim/sulfamethoxazole; TET, tetracycline. All isolates were susceptible to vancomycin and linezolid. ^bMIC values are indicated in μg/ml. The MIC distribution was as follows: ≤ 0.064 μg/ml (n = 957), < 2 μg/ml (n = 187), 2 μg/ml (n = 4), 3 μg/ml (n = 1).