Table 1.

The association of CRISPR-Cas systems with chromosome size, plasmid count, phage count, spacer numbers, number of spacer hit plasmids, and the presence of antibiotic resistance genes among 97 K. pneumoniae genomes.

	CRISPR-Cas systems
	Presence (n = 40)		Absence (n = 57)	p-Value
	Type I-E	Subtype I-E∗
	(n = 23)	(n = 17)
Chromosome size (bp)	5,354,756 (62,628)	5,339,573 (75,216)	5,346,821 (116,544)	0.761, 0.810, 0.507a
Plasmid count	3.52 (2.020)	1.71 (1.448)	3.02 (1.758)	0.269, 0.007, 0.003a
Phage count	5.39 (2.888)	3.18 (1.741)	6.11 (3.063)	0.341, <0.001, 0.008a
Spacer number	36.5 (11.7)	21.3 (4.6)	–	<0.001b
Number of spacer hit plasmids	3.09 (1.6)	3.65 (1.9)	–	0.318
Presence of antibiotic resistance genesc
Aminoglycoside	18 (78.3)	8 (47.1)	44 (77.2)	0.039d
β-Lactam	15 (65.2)	8 (47.1)	43 (75.4)	0.084d
Fluoroquinolones	17 (73.9)	7 (35.3)	36 (63.2)	0.103d
MLS	2 (8.7)	6 (32.3)	23 (40.4)	0.022d
Rifampicin	2 (8.7)	2 (11.8)	4 (7.0)	0.816d
Phenicols	5 (21.7)	12 (70.6)	29 (50.9)	0.260d
Sulfonamide	14 (60.9)	7 (35.3)	36 (63.2)	0.264d
Tetracycline	10 (43.5)	3 (17.6)	15 (26.3)	0.164d
Trimethoprim	14 (60.9)	6 (32.3)	32 (56.1)	0.231d

^ap-Values were shown as CRISPR-negative strains vs. type I-E strains, CRISPR-negative strains vs. subtype I-E^∗ strains, and type I-E strains vs. subtype I-E^∗ strains.

^bp-Value was shown as type I-E strains vs. subtype I-E^∗ strains.

^cOnly antibiotic resistance genes presented in the plasmid were considered (acquired resistance).

^dp-Value was determined by the distribution of antibiotic resistance genes among three groups.

Values were expressed as mean (SD), unless otherwise indicated as number (percent).

MLS, Macrolides, lincosamides, and streptogramines.

The Student’s t-test was applied for all the parametric difference between three groups, and Pearson’s chi-square test was used for the difference in the presence of antibiotic resistance genes between three groups.

Statistically significant correlations (p < 0.05) are shown in bold font.