Multilocus sequence typing and ftsI sequencing: a powerful tool for surveillance of penicillin-binding protein 3-mediated beta-lactam resistance in nontypeable Haemophilus influenzae

Table 4 Frequencies of beta-lactam resistance and clinical characteristics in study groups and in the original population ^a

		rPBP3^c		Bla ^d		Proportions (%) of isolates and patients
Groups of isolates^b	n	n	%	n	%	Anatomical sites			Age groups		Hospitalized^e
						Eye	Ear	Respiratory	0-3	≥50
Resistant group	177	116	66	16	9	28	10	58	44	24	33
Susceptible group	19	0	0	0	0	21	32	42	68	5	11
Remaining isolates	599	0^f	0^f	60^g	10^g	19	15	63	41	22	23
Original population	795^h	116	15	76	10	21	14	62	43	22	25

^aNORM 2007 surveillance population [33], consisting of consecutive routine isolates from patients with eye, ear and respiratory tract infections.
^bSee text and Figure 1 for definition of the study groups (Resistant group and Susceptible group).
^cPBP3-mediated resistance (see Table 1).
^dBeta-lactamase positive.
^eProportions of patients hospitalized at the time of sampling.
^fAssuming that all rPBP3 isolates were selected for the Resistant group.
^gAs reported by the primary laboratories.
^hThirteen isolates were selected for the Resistant group but excluded for various reasons (see Figure 1).