TABLE 1.

Comparison of the average number of peaks in MALDI-TOF MS spectra to the average number of restriction fragments observed upon PFGE^a

Species	No. of MS database strains	Avg no. of peaks per spectrum	No. of variable peaks		Avg no. of PFGE RF	Ratio of variable peak no./PFGE RF
			80%	70%
Acinetobacter baumannii	440	66	50	33	30	2.2
Acinetobacter calcoaceticus	4	66	44	20	23	2.9
Bacteroides fragilis	17	103	69	27	9	11.4
Bordetella pertussis	4	84	40	19	25	3.4
Burkholderia cepacia	6	102	83	47	23	4.5
Campylobacter fetus subsp. fetus	8	110	39	17	13	8.8
Campylobacter jejuni	14	77	46	30	9	8.6
Clostridium difficile	253	69	42	21	13	5.5
Clostridium perfringens	6	90	41	8	11	8.2
Enterobacter cloacae	14	84	70	44	20	4.2
Enterococcus faecalis	97	65	45	32	18	3.7
Escherichia coli	121	98	57	24	16	6.1
Haemophilus influenzae	60	87	66	46	11	7.9
Klebsiella pneumoniae	168	70	48	26	20	3.5
Legionella pneumophila	22	148	62	25	10	14.8
Mycobacterium tuberculosis	11	95	13	0	16	5.9
Neisseria gonorrhoeae	7	102	53	26	15	7.0
Neisseria meningitidis	10	111	60	27	25	4.4
Proteus mirabilis	166	80	49	24	8	10.0
Pseudomonas aeruginosa	149	88	72	48	35	2.5
Salmonella serovar Typhi	6	118	63	27	45	2.6
Shigella dysenteriae	5	108	67	24	19	5.7
Staphylococcus aureus	171	67	48	27	15	4.5
Staphylococcus epidermidis	204	56	44	31	18	3.2
Stenotrophomonas maltophilia	83	97	77	40	15	6.5
Streptococcus mitis	19	84	62	36	18	4.8
Streptococcus pneumoniae	201	87	64	34	15	6.0
Vibrio cholerae	9	113	59	37	25	4.5
Yersinia pestis	2	111	42	10	20	5.5

^aAdapted from Tenover et al. (22). As shown in columns 4 and 5, a peak was considered constant when found in either 80% or 70% of every spectrum for the same species. RF, restriction fragments.