Streptococcus pneumoniae and Haemophilus influenzae in paediatric meningitis patients at Goroka General Hospital, Papua New Guinea: serotype distribution and antimicrobial susceptibility in the pre-vaccine era

Table 3 Proportion of S. pneumoniae and H. influenzae isolates with reduced susceptibility to antibiotics, determined by minimum inhibitory concentration (MIC)

	Number tested	Intermediate resistant	Resistant	Median MIC RS isolates
S. pneumoniae	(n = 180)
Penicillin	177	NA	38 (21.5 %)	0.25
Cotrimoxazole	176	8 (4.5 %)	7 (4.0 %)	2/38
Tetracycline	96	0 (0 %)	4 (4.2 %)	24
Chloramphenicol	176	NA	4 (2.3 %)	16
Ceftriaxone	124	1 (0.8 %)	0 (0 %)	1
Erythromycin	94	0 (0 %)	0 (0 %)	NA
H. influenzae	(n = 165)
Ampicillin	162	8 (4.9 %)	46 (28.4 %)	4
Chloramphenicol	162	NA	51 (31.5 %)	16
Cotrimoxazole	162	8 (4.9 %)	55 (34.0 %)	>32/608

CLSI breakpoints (μg/ml) for resistance (R) and intermediate resistance (IR) [18]
S. pneumoniae: penicillin R ≥0.12; cotrimoxazole IR =1/19–2/38, R ≥4/76; tetracycline IR =4, R ≥8; chloramphenicol R ≥8; ceftriaxone IR =1, R ≥2; erythromycin IR =0.5, R ≥1
H. influenzae: ampicillin IR =2, R ≥4; chloramphenicol IR =4, R ≥8; cotrimoxazole; IR =1/19–2/38, R ≥4/76
RS reduced susceptibility (intermediate resistance and resistance)

ISSN: 1471-2334