Clinical characteristics of burn patients infected with Stenotrophomonas maltophilia and antibiotic resistance of the strains

Abstract

Objective: To investigate the clinical characteristics of burn patients infected with Stenotrophomonas maltophilia (SM) and antibiotic resistance of the strains. Methods: Clinical data of burn patients detected with SM, admitted to our unit from July 2011 to July 2017 were retrospectively analyzed. API 20NE bacteria identification panel or fully automated microbial identification instrument was used to identify pathogen. Minimal inhibitory concentration method was used in drug sensitivity test of levofloxacin, compound sulfamethoxazole, minocycline, and cefoperazone/sulbactam. Annual detection of SM, clinical characteristics and prognosis of patients infected with SM, sample source and detection time of SM, detection of the pathogens and antibiotics application of patients before their detection of SM, and drug resistance of SM to the above four antibiotics were analyzed. The results of drug sensitivity test were analyzed by software WHONET 5.5. Results: (1) There were totally 119 patients detected with SM, with 11, 12, 21, 22, 28, 13, and 12 cases from 2011 to 2017, respectively. (2) Among patients infected with SM, there were 86 (72.3%) males and 33 (27.7%) females. Patients aged more than or equal to 65 years accounted for 11.8% (14/119). Patients aged more than or equal to 18 years and less than 65 years accounted for 76.5% (91/119). Patients aged less than 18 years accounted for 11.8% (14/119). Patients with scald were the most common (totally 72 cases, accounted for 60.5%), and patients with total burn area less than or equal to 10% total body surface area were the most common (totally 35 cases, accounted for 29.4%), too. The proportion of patients with history of basic disease was 16.8% (20/119), with tracheotomy of 46.2% (55/119), with deep vein catheterization of 47.9% (57/119), with history of staying in intensive care unit (ICU) of 61.3% (73/119). Seventy-five (63.0%) patients were cured. Twenty-four (20.2%) patients were improved. Fourteen (11.8%) patients gave up treatment. Six (5.0%) patients died. (3) SM detected from wounds exudate of patients occupied the highest proportion (58.0%, 69/119), which was followed by samples of sputum (17.6%, 21/119), blood (14.3%, 17/119), wound tissue (4.2%, 5/119), catheter (4.2%, 5/119), and urine (1.7%, 2/119). The detection time of SM was 10 hours to 71 days post admission, with the average time of 12.7 days. (4) The proportion of patients detected with pathogens before detection of SM was 66.4% (79/119), and Acinetobacter baumannii and Staphylococcus aureus occupied high proportion among the strains. (5) The proportion of patients using antibiotics before detection of SM was 91.6% (109/119), and 44.0% (48/109) patients used 3 kinds of antibiotics or more. The antibiotics were applied for 271 times. The most frequently used antibiotics were glycopeptides antibiotics (63 times), followed by carbapenems antibiotics (61 times). (6) The total sensitivity rates of SM to levofloxacin and minocycline in 7 years were high (91.6% and 99.4%, respectively). The total sensitivity rate of SM to cefoperazone/sulbactam was low (52.5%). The total sensitivity rate of SM to compound sulfamethoxazole was high (77.6%), and the annual sensitivity rate was higher than 90.0% in recent 3 years. Conclusions: Burn patients infecting SM have high rates of tracheotomy and deep vein catheterization, and most of them stay in ICU and use broad-spectrum antibiotics. SM has high sensitivity to levofloxacin, minocycline, and compound sulfamethoxazole.