Investigation of Virulence Genes of the Predominant Bacteria Associated with Renal Stones and their Correlation with Postoperative Septic Complications

Figures & data

Table 1 Patient Demographics

Variable
Patient’s characteristics
Age, years (Mean ± SD)	49.3±12.3
Gender, no. pts (%)
- Male	77 (38.5)
- Female	123 (61.5)
Comorbidities, no. pts (%)
- Hypertension	58 (29)
- Diabetes	34 (17)
Septic patients, no. pts (%)	8 (4)
Stones’ characteristic
- Stone density (Mean ± SD), HU	737.2±349.8
- Stone size (Median, range), mm^2	42.6 (2.8 −1680)
Operation time (minutes) (Mean ± SD)	88.43±24.34
Bleeding, no. pts (%)
- Yes	11 (5.5)
- No	189 (94.5)
Tracts, no. pts (%)
- Single	180 (90)
- Multiple	20 (10)
Method of disintegration, no. pts (%)
- Ultrasound	152 (76)
- Pneumatic	27 (13.5)
- Combined	21 (10.5)
Positive bacterial culture, no. pts (%)
- Stone samples	70 (35)
- Midstream urine samples	60 (30)
Stone infection in relation to chemical composition, no. pts (%)
- Calcium-based stones	33/77 (42.8)
- Calcium oxalate	27/60 (45)
- Calcium phosphate	5/9 (55.5)
- Calcium oxalate/calcium phosphate	1/8 (12.5)
Non-calcium-based stones	35/110 (31.8)
- Uric acid	28/94 (29.7)
- Cystine	3/10 (30)
- Magnesium ammonium phosphate (Struvite)	4/6 (66.6)
Mixed stones	2/13 (15. 3)
- Calcium oxalate/Uric acid	2/13 (15. 3)

Abbreviations: no. pts, Number of patient; HU, Hounsfield units; SD, standard deviation; mm², square millimeter.

Table 2 Comparison Between Positive Bacterial Stone Culture and Midstream Urine Culture

Type of Bacteria	Positive Midstream Urine Culture, n (%)	Positive Stone Culture, n (%)	Isolates from Midstream Urine Culture Versus Stone Culture
			Similar	Different	Sterile
E. coli	34 (56.6)	10 (14.2)	8	0	2
S. aureus	12 (20)	30 (42.8)	12	6	12
K. pneumonia	8 (13.3)	2 (2.8)	2	0	0
E. faecalis	4 (6.6)	10 (14.2)	4	2	4
P. aeruginosa	2 (3.3)	10 (14.2)	0	2	8
S. epidermidis	0	8 (11.4)	0	2	6
Total, n (%)	60 (100)	70 (100)	26 (37.1)	12 (17.1)	32 (45.7)

Note: Values are expressed as n (%).

Abbreviation: n=Number.

Table 3 The Distribution of the Types of Bacterial Stone Culture in Relation to Its Chemical Composition

	Stone Culture n= 70
Chemical Composition	E. coli n=10	S. aureus n=30	K. pneumonia n=2	E. faecalis n=10	P. aeruginosa n=10	S. epidermidis n=8	P*
Calcium-based stone (n=33)	4	18	1	3	4	3	0.32
- Calcium oxalate (n=27)	3	14	1	2	4	3
- Calcium phosphate (n=5)	1	3	0	1	0	0
- Calcium oxalate/calcium phosphate (n=1)	0	1	0	0	0	0
Non-calcium-based stone (n= 35)	6	11	0	7	6	5
- Uric acid (n=28)	4	9	0	7	5	3
- Cystine (n=3)	1	1	0	0	1	0
- Magnesium ammonium phosphate (Struvite) (n=4)	1	1	0	0	0	2
Mixed stone (n=2)	0	1	1	0	0	0
- Calcium oxalate/Uric acid (n=2)	0	1	1	0	0	0

Note: *Fisher’s exact test.

Abbreviation: n, Number.

Table 4 Distribution of Virulence Genes Among S. aureus Strains and Among Septic and Non-Septic Patients

Distribution of Virulence Genes (n=30)
	Hemolysine Genes		Panton-Valentine Leukocidin Gene	Adhesion Genes			Enterotoxin Genes
	hla	hlb	pvl	fnbA	fnbB	can	seb	sea	sec
Positive, n (%)	28 (93.3)	17 (56.7)	17 (56.7)	22 (73.3)	7 (23.3)	7 (23.3)	5 (16.7)	0	0
Negative, n (%)	2 (6.7)	13 (43.3)	13 (43.3)	8 (26.6)	23 (76.7)	23 (76.7)	25 (83.3)	30 (100)	30 (100)
Distribution of virulence genes among S. aureus strains associated with Septic and non- Septic patients
Septic patients (n=7)	7 (25)	7 (41.1)	7 (41.1)	7 (31.8)	7 (100)	7 (100)	5 (100)	0	0
Non-septic patients (n = 23)	21 (75)	10 (58.8)	10 (58.8)	15 (68.1)	0	0	0	0	0
P value	1.0	0.01*	0.01*	0.1	≤0.001*	≤0.001*	≤0.001*	-	-

Notes: Values are expressed as n (%). p values were obtained from Fisher’s exact test. *Statistically significant.

Abbreviations: hla, Hemolysine a; hlb, Hemolysin b; seb, staphylococcal enterotoxin b; sea, staphylococcal enterotoxin a; sec, staphylococcal enterotoxin c; pvl, Pantone-Valentine leukocidin; can, collagen binding protein; fnbA, fibronectin binding proteins A; fnbB, fibronectin binding proteins B; n, number.

Table 5 Relation of Antibiotic Resistance to Virulence Genes of S. aureus

Antibiotic Genes	hla		hlb		pvl		fnbA		fnbB		can		seb
	hla+ n=28 n (%)	hla- n=2 n(%)	hlb+ n=17 n (%)	hlb- n=13 n (%)	pvl+ n=17 n (%)	pvl- n=13 n (%)	fnbA+ n=22 n (%)	fnbA- n=8 n (%)	fnbB+ n=7 n (%)	fnbB- n=23 n (%)	can+ n=7 n (%)	can- n=23 n (%)	seb+ n=5 n (%)	seb- n=25 n (%)
Vancomycin n=7	7 (25)	0 (0)	4 (23.5)	3 (23)	4 (23.5)	3 (23)	7 (31.8)	0 (0)	0 (0)	7 (30.4)	0 (0)	7 (30.4)	0 (0)	7 (28)
P value	1.0		0.5		0.5		0.1		0.02*		0.02*		0.5
Cefoxitin n=11	9 (32.1)	2 (100)	9 (52.9)	2 (15.3)	7 (41.1)	4 (30.7)	9 (40.9)	2 (25)	5 (71.4)	6 (26)	5 (71.4)	6 (26)	5 (100)	6 (24)
P value	0.2		0.1		0.8		0.3		0.004*		0.004*		0.008*
Amoxicillin/Clavalanic Acid n=9	9 (32.1)	0 (0)	9 (52.9)	0 (0)	9 (52.9)	0 (0)	9 (40.9)	0 (0)	7 (100)	2 (8.6)	7 (100)	2 (8.6)	5 (100)	4 (16)
P value	1.0		0.002*		≤0.001*		0.01*		≤0.001*		≤0.001*		0.001*
Nitrofurantoin n=5	5 (17.8)	0 (0)	2 (11.7)	3 (23)	2 (11.7)	3 (23)	5 (22.7)	0 (0)	0 (0)	5 (21.7)	0 (0)	5 (21.7)	0 (0)	5 (20)
P value	1.0		0.6		0.6		0.2		0.3		0.3		0.5
Norfloxacin n=17	15 (53.5)	2 (100)	13 (76.4)	4 (30.7)	11 (64.7)	6 (46.1)	13 (59)	4 (50)	7 (100)	10 (43.4)	7 (100)	10 (43.4)	5 (100)	12 (48)
P value	0.4		0.02*		0.4		0.6		0.01*		0.01*		0.052
Cefaclor n=9	9 (32.1)	0 (0)	9 (52.9)	0 (0)	7 (41.1)	2 (15.3)	9 (40.9)	0 (0)	5 (71.4)	4 (17.3)	5 (71.4)	4 (17.3)	5 (100)	4 (16)
P value	0.6		0.001*		0.002		0.01*		0.003*		0.003*		0.001*
Gentamicin n=8	8 (28.5)	0 (0)	5 (29.4)	3 (23)	5 (29.4)	3 (23)	8 (36.3)	0 (0)	3 (42.8)	5 (21.7)	3 (42.8)	5 (21.7)	3 (60)	5 (20)
P value	1.0		0.5		0.3		0.07		0.6		0.6		0.2
Cephalotin n=20	20 (71.4)	0 (0)	13 (76.4)	7 (53.8)	17 (100)	3 (23)	16 (72.7)	4 (50)	7 (100)	13 (56.5)	7 (100)	13 (56.5)	5 (100)	15 (60)
P value	0.1		0.2		≤0.001*		0.3		0.06		0.06		0.1
Ampicillin–sulbactam n=5	5 (17.8)	0 (0)	5 (29.4)	0 (0)	5 (29.4)	0 (0)	5 (22.7)	0 (0)	3 (42.8)	2 (8.6)	3 (42.8)	2 (8.6)	3 (60)	2 (8)
P value	1.0		≤0.001*		≤0.001*		0.4		≤0.001*		≤0.001*		0.003*
Levofloxacin n=8	8 (28.5)	0 (0)	6 (35.2)	2 (15.3)	6 (35.2)	2 (15.3)	6 (27.2)	2 (25)	2 (28.5)	6 (26)	2 (28.5)	6 (26)	2 (40)	6 (24)
P value	1.0		0.1		0.1		1.0		0.04*		0.04*		0.7

Notes: Values are expressed as n (%). p values were obtained from Fisher’s exact test. *Statistically significant.

Abbreviations: hla, hemolysine a; hlb, hemolysine b; seb, staphylococcal enterotoxin b; pvl, Pantone-Valentine leukocidin; can, collagen binding protein; fnbA, fibronectin binding proteins A; fnbB, fibronectin binding proteins B; n, number; (+), presence of gene; (-), absence of gene.

Data Availability

The original contributions presented in the study are included in the article and Supplementary Materials.