The objective of the study is to evaluate the efficacy of minocycline for treatment Stenotrophomonas maltophilia infection. The hypothesis of study is the combination therapy with minocycline would be better than the monotherapy for treatment Stenotrophomonas maltophilia infection.

• Investigator inform patient or their relatives about all topics in project, eligible criteria, method, material and monitoring treatment.
• After patient or their relatives are appreciated to join this project, patients will be randomly allocated to either levofloxacin or cotrimoxazole plus placebo (monotherapy plus placebo) or levofloxacin or cotrimoxazole plus minocycline (combination therapy).
• Duration of treatment is determined by site and severity of infection, approximately 7-28 days.
• Sample size calculation, by two independent proportions formula, the investigators estimate the mortality rate about 54 % in monotherapy group and mortality rate about 27 % in combination therapy with minocycline group, with 2-sided 95% Confidence interval; therefore,51 persons are needed each group.
• The investigators estimate gather data about 112 persons. (56 participants with monotherapy and 56 participants with combination therapy (minocycline plus another antibiotic drug from intervention trial))
• The categorical variables are reported as frequencies and percentages, while continuous variables are reported as means ± standard deviations for normally distributed data and median ± range for non-normally distributed data. The data collected from patients are compared using Chi-square tests or Fisher's exact tests for categorical variables and using t-tests or Mann-Whitney U-tests for continuous variables.
• During the study is performing, all unexpected adverse event definitely report to Siriraj institutional Review Board immediately, in addition to subjects or their relatives.

Inclusion Criteria:

• The infection caused by Stenotrophomonas maltophilia
• The duration of treatment approximately between 7-28 days
• The patients can take minocycline capsule via oral or nasogastric tube feeding.
• The patients are anticipated to live more than 48 hrs after participation.
• In case of an antibiotic drug administration for treatment Stenotrophomonas maltophilia beforehand, it should not exceed 48 hrs.
• All of participants should be willing to join this project.

Exclusion Criteria:

• Pregnancy and lactation
• The patients with active hepatitis
• The patients with history of minocycline allergy

Double blind, Placebo Controlled