[Identification of respiratory pathogenic bacteria and analysis of drug resistance results of patients with nursing home acquired pneumonia in a nursing home in Shanghai City from 2021 to 2023].

This study analyzed the respiratory bacterial characteristics and antibiotic resistance of nursing home acquired pneumonia (NHAP) patients in social care nursing homes in Shanghai City, revealing a pathogen spectrum exhibiting features of both community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP). These findings provide scientific evidence for clinical management and hospital infection control in similar community-run nursing homes and elderly care facilities. A retrospective method was employed to collect sputum samples from 945 NHAP patients at Shanghai Yingkang Nursing Home from January 2021 to December 2023. Bacterial cultures were used to detect bacteria, which were identified using the VITEK® 2 compact fully automated microbial analysis system, and antimicrobial susceptibility testing was conducted using the disk diffusion method. Analysis of bacterial distribution and antibiotic resistance was conducted using chi-square tests to compare differences in bacterial distribution among different age groups, patients with varying living statuses (bedridden vs. non-bedridden), and those with single or multiple bacterial infections. Results revealed a total of 1 702 bacterial isolates, with Gram-negative bacteria accounting for 80.7% (1 374/1 702). The predominant species were Pseudomonas aeruginosa (16.6%, 283/1 702), Klebsiella pneumoniae (16.1%, 274/1 702), Acinetobacter baumannii (14.8%, 252/1 702), and Escherichia coli (13.2%, 225/1 702). Gram-positive bacteria constituted 19.3% (328/1 702), predominantly Staphylococcus aureus (18.3%, 312/1 702). With Escherichia coli exhibiting resistance rates of >80% to penicillin (Ampicillin), cephalosporins, and aztreonam; Acinetobacter baumannii exhibiting resistance rates of >76% to carbapenems; and MRSA(Methicillin-resistance Staphylococcus aureus) accounting for 90.7% (283/312) of Staphylococcus aureus. Key resistance profiles varied, with Klebsiella pneumoniae exhibiting a resistance rate of 24.1% (66/274) to imipenem; Pseudomonas aeruginosa exhibiting a resistance rate of 49.8% (141/283) to imipenem; all Gram-positive cocci remained susceptible to vancomycin and linezolid. Population characteristics revealed that bacterial detection rates were 50.2% (854/1 702) among patients aged >84 years. With significantly increased detection rates for Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae across higher age groups (χ²=9.28, P<0.05). Bacterial detection rates were significantly higher among long-term bedridden patients compared to non-bedridden patients [e.g., Acinetobacter baumannii: 78.2% (197/252) vs. 21.8% (55/252), χ²=46.6, P<0.001]. The infection pattern was primarily single bacterial infection, accounting for 77.6% (734/945), with Staphylococcus aureus accounting for 30.4% (223/734); multiple infections were primarily Staphylococcus aureus+Pseudomonas aeruginosa combinations, accounting for 14.1% (28/198). In conclusion, the pathogen spectrum of NHAP exhibits characteristics of both community-acquired and hospital-acquired infections, with MRSA and Carbapenem-resistant Klebsiella pneumoniae(CRKP) and Carbapenem-Resistant Acinetobacter baumannii(CRAB) being particularly problematic. Treatment strategies should be individualized based on age and living conditions. Carbapenem-susceptible antibiotics should be prioritized based on antimicrobial susceptibility testing results, while beta-lactam and fluoroquinolone antibiotics should be used cautiously for empirical therapy.