In vitro combination of tigecycline with other antibiotics in Stenotrophomonas maltophilia isolates

Background/aim: The aim of this study was to determine the usefulness of tigecycline in combination treatment of Stenotrophomonas maltophilia infections by evaluating the in vitro synergistic effects of tigecycline with various antibiotics using the E-test method. Materials and methods: Synergy testing by E-test was performed with various antibiotic combinations in 10 S. maltophilia isolates identified as a cause of infection. The antibiotics used in the study included tigecycline (TGC), cefoperazone-sulbactam (CPS), ceftazidime (TZ), levofloxacin (LEV), and trimethoprim-sulfamethoxazole (cotrimoxazole) (TS). Four different combinations (TGCCPS, TGC-TZ, TGC-LEV, TGC-TS) were studied with the E-test synergy method. Results: S. maltophilia isolates were found to have the highest level of susceptibility to trimethoprim-sulfamethoxazole, tigecycline, and levofloxacin. The fractional inhibitory concentration (FIC) index was calculated as FIC = MICAB/MICA + MICBA/MICB. The FIC index values were calculated and classified as synergistic (FIC < 0.5), additive (FIC = 0.5­1), indifferent (FIC = 1­4), and antagonistic (FIC > 4). According to FIC index values, synergy was found with the highest rate with TGC-CPS and TGC-LEV combinations (20%). Antagonistic activity was not found in any combination. Conclusion: When trimethoprim-sulfamethoxazole cannot be used because of resistance or allergy, tigecycline alone or in combination may be included as an alternative option. Although in vitro results are promising, clinical data are required.

The Impact of Vaccination Among Hospitalized Patients with the Diagnosis of COVID-19.

Objective: We aimed to investigate the vaccination status and the risk factors for the intensive care unit (ICU) support need of the laboratory-confirmed breakthrough COVID-19 infection inpatients. Materials and Methods: This multi-center point-prevalence study was conducted on inpatients, divided into two groups as 'fully' and 'partially' vaccinated according to COVID-19 vaccination status. Results: Totally 516 patients were included in the study. The median age was 65 (55-77), and 53.5% (n=276) of the patients were male. Hypertension (41.9%, n=216), diabetes mellitus (DM) (31.8%, n=164), and coronary artery disease (CAD) (16.3%, n=84) were the predominant comorbidities. Patients were divided into two groups ICU (n=196) and non-ICU (n=301). Hypertension (p=0.026), DM (p=0.048), and congestive heart failure (CHF) (p=0.005) were significantly higher in ICU patients and the median age was younger among non-ICU patients (p=0.033). Of patients, 16.9% (n=87) were fully vaccinated, and this group's need for ICU support was statistically significantly lower (p=0.021). Conclusion: We conclude that older age, hypertension, DM, CHF, and being partially vaccinated were associated with the need for ICU support. Therefore, all countries should continuously monitor post-vaccination breakthrough COVID-19 infections to determine the national booster vaccine administration approach that will provide vulnerable individuals the highest protection.