Comparative assessment of the mouse immune responses to colistin-resistant and colistin-sensitive isolates of Acinetobacter baumannii.

Acinetobacter baumannii is known as the most frequent species in clinical samples that is responsible for a large number of nosocomial infection outbreaks. The colistin-resistance of this bacterium has been found to be increasing. This study aimed to evaluate the immune response to colistin-susceptible and colistin-resistant A. baumannii isolates in a mouse model. Samples were prepared from the wounds of patients suspected of A. baumannii admitted to the intensive care unit of Namazi Hospital in Shiraz. Antibiotic susceptibility was studied by disk diffusion and broth microdilution according to CLSI and EUCAST criteria. Among the isolates, one colistin-sensitive isolate and one colistin-resistant isolate were injected intraperitoneally to BALB/C mice. Blood samples were collected after 4 h and cytokines (IL1-ß, IL-12, IFN γ, and IL-10) and surface markers (CD4, CD8, CD3, and CD45) were determined by ELISA and flow cytometry. Then, hematologic and histopathological factors were analyzed, and colony count in lung, liver, kidney, and spleen tissues were also performed. The results showed that levels of cytokines (IL1-ß, IL-12, IFN γ, and IL-10) and markers (CD4, CD8, CD3 and CD45) were higher in mice receiving colistin-resistant A. baumannii isolates than in mice receiving colistin-sensitive A. baumannii isolates, indicating that colistin-resistant isolates 4 h following the intraperitoneal injection stimulated host innate immune system better and produced a stronger immune response. On the other hand, histopathological findings showed inflammatory cell infiltration, hyperemia, and tissue damage. In addition, the bacterial load and tissue damage in the lung was higher than other tissues. The results of this study can have promising potential for the development of a prevention and treatment strategy based on cellular immune response for infection caused by colistin-sensitive and colistin-resistant A. baumannii.

Economic Burden Of Inappropriate Empiric Antibiotic Therapy: A Report From Southern Iran.

INTRODUCTION: Widespread inappropriate antibiotic prescribing by healthcare professionals in the hospital setting is a great concern that may cause many undesirable consequences. Adherences to antibiotic guidelines have proven to be a simple and effective intervention to guide the choice of appropriate empiric antibiotic regimens and reduce the unnecessary variations in the practice among practitioners. The objective of this study was to evaluate the prescription patterns of empiric antibiotic therapy in relation to treatment guidelines and the economic burden of discordance with guidelines in a major referral Iranian university hospital. METHOD: Hospital records of hospitalized patients with empiric antibiotic prescription, from September 2016 to February 2017 were reviewed. The process consisted of comparing empiric antimicrobial administration with institutional guidelines for each patient by a clinical pharmacist and an infectious disease specialist to evaluate the appropriate utilization of antibiotics. Adherence to guideline, the cost of antibiotics usage for each patient and the excess cost consequent from discordance with guideline was calculated. RESULTS: The most inappropriate prescribed antibiotics were carbapenems and aminoglycosides. Overall guideline adherence was 27.8%. Frequency of antibiotic usage incompatibility with the guidelines on the basis of dosing interval, duration of therapy and drug indication were 31.46%, 29.44% and 19.36%, respectively. General surgery and internal medicine wards had the least and the most inappropriate antibiotic administration, respectively. Totally antibiotic usage cost was 578,959.39 USD (24,316,294,800 Iranian Rials, IRR) for 6 months, which the excess costs of inappropriate antibiotic prescribing, was 471,319.69 USD (19,795,427,225 IRR). The estimated annual excess cost is 942,639.38 USD (39,590,854,450 IRR). CONCLUSION: In this research, physicians' adherence with guidelines for empiric antibiotic therapy was low which was led to 471,319.69 USD excess costs. These results urge institution policy makers to develop guidelines to ensure active dissemination and implementation of them to decrease inappropriate antibiotic usage.