The Correlation Between Biofilm-Forming Ability of Community-Acquired Methicillin-Resistant Staphylococcus aureus Isolated from the Respiratory Tract and Clinical Characteristics in Children

Figures & data

Figure 1 Flow chart of the simplified process. Created with BioRender.com.

Abbreviations: CA-MRSA, community-acquired methicillin-resistant Staphylococcus aureus; PCR, polymerase chain reaction; SEM, scanning electron microscopy.

Table 1 General Information and Clinical Characteristics of Enrolled Children

Characteristics	CA-MRSA Isolates (n=53)
Age (month), median (range)	11.1 (0.3–144)
Gender (female vs male), n (%)	23 vs 30 (43.4% vs 56.6%)
Preterm birth, n (%)	3 (5.7%)
Medical history in the last year, n (%)
Pneumonia	3 (5.7%)
Congenital heart disease	1 (1.9%)
None	49 (92.4%)
Clinical sources, n (%)
Sputum	26 (49.1%)
Bronchoalveolar Lavage Fluid	8 (15.0%)
Pharyngeal swab	17 (32.1%)
Pleural effusion	2 (3.8%)
Department, n (%)
Respiratory department	22 (41.5%)
Neonatal department	11 (20.8%)
Neurosurgery	7 (13.2%)
PICU	4 (7.5%)
Other Clinical Departments	9 (17.0%)
Categories of clinical phenotype, n (%)
LRTI	39 (73.6%)
Tonsillitis	2 (3.8%)
Lymphadenitis	1 (1.9%)
Sepsis	3 (5.7%)
Asymptomatic colonization	8 (15.0%)
Outcomes, n (%)
Recovery	50 (94.3%)
Death or failure to treatment	3 (5.7%)

Abbreviations: CA-MRSA, community-acquired methicillin-resistant Staphylococcus aureus; PICU, pediatric intensive care unit; LRTI, lower respiratory tract infection.

Table 2 The Antimicrobial Resistance Profiling of 53 CA-MRSA Isolates

Antimicrobials	CA-MRSA (n=53)
	No.*	%
Ceftaroline Fosamil	53	100.0
Oxacillin	53	100.0
Penicillin	53	100.0
Erythromycin	47	88.7
Clindamycin	46	86.8
Moxifloxacin	5	9.4
Sulfamethoxazole/trimethoprim	2	3.8
Levofloxacin	2	3.8
Gentamicin	1	1.9
Linezolid	0	0
Daptomycin	0	0
Rifampicin	0	0
Tigecycline	0	0
Teicoplanin	0	0
Vancomycin	0	0

Note: No.*indicates the number of isolates that were resistant to the antimicrobials.

Figure 2 Molecular characteristics of 53 CA-MRSA isolates. Evolution patterns of the 53 CA-MRSA isolates (calculated by goeBURST hierarchical clustering analysis) and the carriage of PVL genes among the different MLST groups.

Abbreviations: MLST, multilocus sequence typing; CC, clonal complex; ST, sequence type; PVL, Panton-Valentine leukocidin.

Table 3 Clinical Characteristics Between CA-MRSA Groups with Different Biofilm-Forming Capacity

	CA-MRSA Isolates (n=53)
Characteristic	Weak Producer (n=27)	Strong Producer (n=26)	P value
No. of patients (male/female)	15/12	15/11	0.548
Age (month), median (IQR)	23.0 (71.0)	5.1 (61.8)	0.722
Hospital stay length (days), median (IQR)	5.5 (7.0)	7.0 (5.0)	0.180
% Patients with LRTI	59.3 (16/27)	88.5 (23/26)	0.026
% Cough	51.9 (14/27)	84.6 (22/26)	0.006
% Fever	37.0 (10/27)	46.2 (12/26)	0.347
% Shortness of breath	18.5 (5/27)	26.9 (7/26)	0.344
WBC on admission, median (IQR)	8.4 (5.0)	8.7 (4.5)	0.943
CRP on admission, median (IQR)	1.2 (4.5)	2.0 (11.5)	0.202
% Patients with increased PCT	33.3 (9/27)	34.6 (9/26)	0.576
% Patients with increased IL-6	25.9 (7/27)	26.9 (7/26)	0.590
% Patients with increased IL-10	14.8 (4/27)	23.1 (6/26)	0.339
% Patients with Chest Imaging Findings^a	37.0 (10/27)	76.9 (20/26)	0.002
% Antibiotic resistance^b, n (%)	81.5 (22/27)	96.2 (25/26)	0.104
% Isolates with PVL	37.0 (10/27)	34.6 (9/26)	0.541

Notes: ^aChest imaging findings include definite pneumonia, atelectasis, pleural effusion, and lung necrosis; ^bantibiotic resistance means that related isolates were resistant to more than 4 classes of antibiotics.

Abbreviations: No, number; LRTI, lower respiratory tract infection; WBC, white blood cell; CRP, C-reactive protein; IQR, interquartile range; PCT, procalcitonin; PVL, Panton-Valentine leukocidin.

Figure 3 Biofilm formation by 53 CA-MRSA isolates. (A) Representative images and quantification of biofilm formation of the two CA-MRSA strain groups by crystal violet staining. (B) Representative scanning electron microscopy images of CA-MRSA biofilms in both groups.

Figure 4 The impacts of CA-MRSA biofilm-forming in children with LRTI. (A) The higher ratio of patients with a duration of cough over two weeks in strong biofilm-forming group (P=0.037). (B) The line graph indicates that CA-MRSA biofilm formation increased the duration of cough in pediatric patients with LRTI (P=0.0496). (C) Higher proportion of patients needing to adjust antibiotics in the strong biofilm-forming group.