[Risk factors and etiological analysis of ventilator-associated pneumonia: three year's cases analysis of intensive care unit in county hospital].

OBJECTIVE: To investigate the risk factors of ventilator-associated pneumonia (VAP) and the distribution and drug resistance of pathogens in intensive care unit (ICU) of county hospital.

METHODS: 234 patients on mechanical ventilation for more than 48 hours admitted to ICU of Shexian People's Hospital of Huangshan City from January 2016 to June 2018 were enrolled. The clinical data of all patients including gender, age, past medical history, exposure to antibiotics, medication, the duration of mechanical ventilation, the length of ICU stay, serum albumin, tracheotomy, re-intubation, prognosis, and pathogenic bacteria and drug sensitivity test of VAP patients were collected. The patients were divided into VAP group and non-VAP group according to the occurrence of VAP. The differences of each index between the two groups were compared. The risk factors of VAP were analyzed by multivariate Logistic regression. The distribution and drug resistance of pathogenic bacteria in sputum culture of lower respiratory tract of VAP patients were analyzed.

RESULTS: Among the 234 patients on mechanical ventilation, 95 patients had VAP, and the incidence of VAP was 40.60%. (1) Risk factors of VAP: it was shown by univariate analysis that there were significant differences between VAP patients and non-VAP patients in past history, the duration of mechanical ventilation, the length of ICU stay, albumin < 28 g/L, antibiotic exposure and tracheotomy, but there were no significant differences in gender, age, glucocorticoid, sedative, gastric motility and coma between the two groups. It was shown by multivariate Logistic regression analysis that brain injury and cerebrovascular accident, the duration of mechanical ventilation > 7 days, albumin < 28 g/L and tracheotomy were independent risk factors for VAP occurrence [brain injury: odds ratio (OR) = 41.40, 95% confidence interval (95%CI) = 2.14-799.60, P = 0.014; cerebrovascular accident: OR = 36.07, 95%CI = 1.86-699.64, P = 0.018; the duration of mechanical ventilation > 7 days: OR = 1.23, 95%CI = 1.11-1.36, P < 0.001; albumin < 28 g/L: OR = 2.27, 95%CI = 1.03-5.01, P = 0.042; tracheotomy: OR = 3.33, 95%CI = 1.30-8.56, P = 0.012]. (2) Distribution and drug resistance of VAP pathogens: a total of 108 strains of pathogens were isolated from sputum samples of 95 patients with VAP. Gram-negative (G- ) bacteria accounted for 86.11% (93/108). The isolation rate of Klebsiella pneumoniae was the highest, reaching 31.48% (34/108); the isolation rates of Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter baumannii were 22.22% (24/108), 8.33% (9/108) and 9.26% (10/108), respectively. Gram-positive (G+ ) bacteria accounted for 6.48% (7/108), of which Staphylococcus aureus was 4.63% (5/108); and fungi was 7.41% (8/108). Drug resistance analysis showed that Klebsiella pneumoniae was 100% sensitive to amikacin (AMK), meropenem (MEM) and polymyxin (POL), and were suggested as the preferred drug. Pseudomonas aeruginosa was 100% sensitive to AMK, tobramycin (TOB) and POL, but 100% resistant to compound trimethoprim (PCST). Stenotrophomonas maltophilia was 100% sensitive to PCST and 100% resistant to AMK, piperacillin (PIP), piperacillin tazobactam (TZP) and TOB. Acinetobacter baumannii was 100% sensitive to cefoxitin (FOX), cefuroxime (CXM) and POT. Staphylococcus aureus was 100% sensitive to gentamicin (GEN), furantoin (NIT), rifampicin (RIF), vancomycin (VAN) and teicoplanin (TEC), while the drug resistance to clindamycin (CLI) and penicillin (PEN) was high (both 80.00%). Most pathogens were multidrug-resistant. The mortality of patients with multidrug resistant bacteria infection was significantly higher than that of non-multidrug resistant bacteria infection [51.85% (28/52) vs. 30.56% (11/36), χ 2 = 4.240, P = 0.046].

CONCLUSIONS: VAP was associated with brain injury and cerebrovascular accident, duration of mechanical ventilation < 7 days, albumin > 28 g/L and tracheotomy. VAP patients were infected mainly with G- bacteria and showed multiple drug resistance.