Serotyping of Klebsiella pneumoniae and Its Relation with Capsule-Associated Virulence Genes, Antimicrobial Resistance Pattern, and Clinical Infections: A Descriptive Study in Medical Practice

Figures & data

Table 1 Antibiotic Pattern of K. pneumoniae Isolates

No. of Profiles	Resistance Profiles	No. of AB	No. of Isolates^a
I	PTZ, NI	2	2
II	SXT, NI	2	2
III	CP, SXT, CAZ, CTX, NI	5	3
IV	SXT, CAZ, CTX, NI, LEV	5	2
V	CP, SXT, CAZ, CTX, PTZ, NI	6	2
VI	GM, CP, SXT, CAZ, CTX, PTZ, NI	7	2
VII	GM, CP, SXT, CAZ, CTX, PTZ, NI	7	2
VIII	GM, CP, AN, SXT, CAZ, CTX, PTZ, NI	8	5
IX	GM, CP, AN, IMI, MEM, SXT, CAZ, CTX, PTZ, NI, LEV	11	2

Note: ^aProfile of two or more similar isolates was included.

Abbreviations: GM, gentamicin; CP, ciprofloxacin; AN, amikacin; IMI, imipenem; MEM, meropenem; SXT, co-trimoxazole; CAZ, ceftazidime; CTX, cefotaxime; PTZ, piperacillin-tazobactam; NI, nitrofurantoin; LEV, levofloxacin; AB, antibiotic disks.

Table 2 Relation of K-Serotypes with Capsule-Associated Virulence Factors in Various Clinical Wards

Number of
Wards	K. pneumoniae N (%)	K-Serotypes			Virulence Factors
		K54 (n=18)	K20 (n=13)	K5 (n=5)	wcaG (n=18)	rmpA (n=13)	uge (n=57)	ycfM (n=56)	wabG (n=54)
Burn ICU	7 (11.5)	2	5*	0	2	4*	7	7	7
General ICU	6 (9.8)	1	0	0	1	0	6	6	6
Infectious ICU	4 (6.6)	4	1	0	4	0	3	4	4
Internal ICU	3 (4.9)	0	0	1	0	0	2	2	2
Surgery ICU	2 (3.3)	1	0	1	1	0	2	2	2
Internal	8 (13.1)	2	0	2	2	0	8	7	7
Burn	6 (9.8)	1	4*	0	1	5*	6	5	5
Urology	6 (9.8)	2	0	0	2	1	5	5	4
Surgery	2 (3.3)	2	0	0	2	2	2	2	2
Emergency	2 (3.3)	0	0	0	0	0	2	2	2
Infectious	4 (6.6)	1	2	0	1	0	4	4	3
Out-patients	11 (18)	2	1	1	2	1	10	10	10

Note: *P-value<0.05, calculated by Chi-square test or Fisher exact test.

Abbreviations: ICU, intensive care unit; K, capsular polysaccharide (K antigen).

Table 3 Demographic and Clinical Data of 61 K. pneumoniae-Infected Patients and Relation with Serotypes

Variables	Number (%)	Statistically Significant Association with Capsular Serotypes
Gender
Male	28 (45.9)	–
Female	33 (54.1)	K20*
Infection setting
Hospital-acquired	34 (55.6)	K5, K20, K54*
Community-acquired	27 (44.4)	-
Age (mean ± SD)	56.70 ± 23.42 years	-
Accommodation
Urban	43 (70.5)	-
Rural	18 (29.5)	-
Underlying medical conditions
ICU stay	22 (36.2)	-
Bed-ridden	43 (70.5)	-
Radiography	34 (55.7)	-
Ultrasonography	21 (34.4)	-
CT scan	18 (29.5)	-
Tracheostomy	5 (8.2)	-
Bronchoscopy	4 (6.6)	-
Cystoscopy	4 (6.6)	-
Skin graft	11(18)	K20*
Mechanical ventilation	9 (14.8)	-
Pneumonia	7 (11.5)	-
Surgery procedure	18 (29.5)	-
Prior antibiotic usage	43 (70.5)	-
Diseases
Pulmonary	11 (18)	K54*
Renal diseases and UTI	20 (32.7)	-
Gastrointestinal	7 (11.4)	-
Infectious disease	7 (11.4)	-
Ulcer and abscess	6 (9.7)	-
Burn	10 (16.4)	K20*
Diabetes mellitus	5 (8.2)	-
DJ procedure	5 (8.2)	-
Bacteremia	3 (4.9)	-
Cardiovascular	2 (3.3)	-
Hyperplasia of prostate	2 (3.3)	-
Syndromes
Kimmel-Wilson syndrome	4 (6.6)	-
Respiratory distress syndrome	2 (3.3)	-
Outcome
Survived	50 (82)	-
Died	11 (18)	-

Note: *P-value<0.05, calculated by Chi-square test or Fisher exact test.

Abbreviations: SD, standard deviation; ICU, intensive care unit; CT, computed tomography; UTI, urinary tract infection; DJ, double J; K, capsular polysaccharide (K antigen).

Table 4 Distribution of Putative Capsule-Associated Virulence Genes in K. pneumoniae in Predominant Capsular Serotypes

		Capsule-Associated Genes^a
		rmpA (n=13)	wcaG (n=18)	uge (n=57)	ycfM (n=56)	wabG (n=54)
Hospital-acquired isolates		12*	13*	32	31	31
Capsular serotypes	K5 (n=5)	0	2	5	5	5
	K20 (n=13)	8*	3	12	12	12
	K54 (n=18)	6	18*	18	17	18

Note: ^aAs the capsule-associated genes were common among two serotypes, thus, the numbers cannot add up to numbers mentioned for each of them. *P-value<0.05, calculated by Chi-square test or Fisher exact test.

Abbreviation: K, capsular polysaccharide (K antigen).

Figure 1 Distribution of capsular serotypes and capsule-associated virulence genes among the isolates collected from male and female specimens.

Note: *Higher prevalence of K20 serotype was found in the clinical specimens collected from females in comparison to males (p-value = 0.02). NT: the isolates that did not belong to the K1, K2, K5, K20, K54, or K57 serotype.

Abbreviations: K, capsular polysaccharide (K antigen); NT, non-typeable.

Table 5 Correlation of Mucoid Phenotype with K-Serotypes, Capsule-Associated Virulence Genes, and ESBL Among K. pneumoniae Isolates

Number (%) of
Mucoid phenotype	Typeable isolate (n=36)	Capsular serotypes			NT^a isolate (n=25)	Capsule-associated virulence factors					Extended-spectrum beta-lactamase
		K5 (n=5)	K20 (n=13)	K54 (n=18)		rmpA (n=13)	wcaG (n=18)	uge (n=57)	ycfM (n=56)	wabG (n=54)	ESBL isolates (n=36)	K5, ESBL^b (n=2)	K20, ESBL^b (n=9)	K54, ESBL^b (n=12)	rmpA, ESBL^c (n=12)	Non-ESBL isolates (n=25)
Total=16 (26.22%)	14 (87.5)*	1 (6.25)	10 (62.5)*	3 (18.7)	2 (12.5)	10 (62.5)*	3 (18.7)	15 (93.7)	15 (93.7)	15 (93.7)	10 (62.5)	0	7 (43.7)*	3 (18.7)	7 (43.7)*	6 (37.5)

Note: ^aNT, the isolates that were not found to be typeable with K1, K2, K5, K20, K54, and K57 primers. ^bIsolates with both K5/K20 serotype and ESBL positivity. ^cIsolates with both rmpA gene and ESBL positivity (the only virulence factor with a significant association with mucoid phenotype). *P-value<0.05, calculated by Chi-square test or Fisher exact test.

Abbreviations: NT, non-typeable; ESBL, extended-spectrum beta-lactamase; K, capsular polysaccharide (K antigen).