Genomic Determinants of Pathogenicity and Antimicrobial Resistance of Nosocomial Acinetobacter baumannii Clinical Isolates of Hospitalized Patients (2019–2021) from a Sentinel Hospital in Hangzhou, China

Figures & data

Table 1 Distribution of Acinetobacter baumannii Based on Mode of Acquisition of Infection and in Various Clinical Specimens

Clinical Departments	Clinical Specimens					Total
	Blood	Respiratory	Urine	Bile	Pus
Internal Medicine	0	36	3	1	0	40
Surgery	0	4	1	1	0	6
ICU	9	66	1	0	1	77
Total	9	106	5	2	1	123

Table 2 Correlation Between the Clinical Diagnosis and Antibiotics Used in the Infected Patients

Diagnosis	Cephalosporins	Antibiotics				Total
		Cefoperazone/Sulbactam	Piperacillin /Tazobactam	Carbapenems	Co-Medication
Pulmonary infection	11 (11.46%)	23 (23.96%)	34 (35.42%)	15 (5.63%)	2 (2.08%)	85 (88.54%)
Biliary tract infection	1 (1.04%)	0	0	0	0	1 (1.04%)
Bloodstream infections	0	2 (2.08%)	0	1 (1.04%)	6 (6.25%)	9 (9.36%)
Wound infection	0	0	0	0	1 (1.04%)	1 (1.04%)
Total	12 (12.5%)	25 (26.04%)	34 (35.42%)	16 (16.67%)	9 (9.38%)	96

Notes: Cephalosporins: ceftriaxone, cefdinir, cefotaxime, ceftazidime, ceftizoxime. Cephalosporin enzyme inhibitors: cefoperazone-sulbactam. Carbapenems: meropenem, imipenem, ertapenem. Penicillin enzyme inhibitors; piperacillin-tazobactam. Co-Medication refers to the simultaneous use of two or more antibiotics. Such as cephalosporins + quinolone, cephalosporins + lincosamide, cephalosporins + carbapenem, cephalosporin + peptides, cephalosporins + penicillins, cephalosporin+ tetracyclines, peptides + tetracyclines + cephalosporins. The figures (n) represents the number of patients, and the percentage (%) represents the number of patients/total number of patients treated. The antibiotics listed in Table 2 are the therapeutic drugs after Acinetobacter baumannii was detected and according to the results of antimicrobial sensitivity testing.

Figure 1 Distribution of antimicrobial resistance (AMR) pattern of 123 Acinetobacter baumannii clinical isolates.

Notes: The AMR pattern of resistant isolates after antimicrobial susceptibility testing of all isolates (n=123). The percentage (%) is calculated by the number of each antibiotic resistance, intermediate or susceptible isolate/total number of isolates.

Abbreviations: CRO, ceftriaxone; CSL, cefoperazone-sulbactam sodium; IMP, imipenem; MEM, meropenem; CIP, ciprofloxacin; LVX, levofloxacin; CAZ, ceftazidime; FEP, cefepime; GEN, gentamicin; TOB, tobramycin; TGC, tigecycline; SXT, cotrimoxazole.

Figure 2 The presence of antimicrobial resistance genes (ARGs) of 123 Acinetobacter baumannii clinical isolates.

Notes: The percentage (%) is calculated by the number of each ARGs /total number of isolates.

Figure 3 Multi-locus sequence typing (MLST) and minimum spanning tree (MST) population analysis of 123 Acinetobacter baumannii clinical isolates from the different clinical departments.

Notes: (a) Genetic background with sequence types (STs) of 123 A. baumannii isolates from various clinical departments. (b) Minimum spanning tree (MST) based on STs profiles of 123A. baumannii clinical isolates. Each circle represents an ST and the size of the circle is proportional to the number of isolates, and the color within the circle represents the section of the isolate. Links between circles are indicated according to the number of allelic mismatches between STs.

Figure 4 Comparison of antimicrobial resistance phenotypes and genotypes, STs and VFGs between isolates from different clinical departments.

Notes: Based on (a) Antimicrobial resistance phenotypes, (b) Antimicrobial resistance genotypes, (c) STs and (d) VFGs. The numbers in cells correspond to the percentage (%).

Figure 5 Phylogenetic analysis and heat map of the detection of ARGs and VFGs among the 123 Acinetobacter baumannii clinical isolates.

Notes: Acinetobacter baumannii isolates were used to construct a maximum-likelihood tree with 100 bootstraps. Single nucleotide polymorphisms SNPs-based phylogenetic tree of A. baumannii genomes.4744 SNPs were identified on the basis of whole-genome alignment of 123 sequenced. ATCC19606 was used as the reference strain and Acinetobacter lwoffii was used as an out-group strain. The upper branch was dominated by strains from internal medicine “(blue)” and surgery “(green)”, with a large number of strains from the ICU “(orange)” in the lower branch. The tree scale represents the genetic distance between the isolates used to construct the tree.