[Multiresistant pathogens--a challenge for clinicians]

Bloodstream Infections

Bacteremia and sepsis are conditions associated with high mortality and are of great impact to health care operations. Among the top causes of mortality in the United States, these conditions cause over 600 fatalities each day. Empiric, broad-spectrum treatment is a common but often a costly approach that may fail to effectively target the correct microbe, may inadvertently harm patients via antimicrobial toxicity or downstream antimicrobial resistance. To meet the diagnostic challenges of bacteremia and sepsis, laboratories must understand the complexity of diagnosing and treating septic patients, in order to focus on creating algorithms that can help direct a more targeted approach to antimicrobial therapy and synergize with existing clinical practices defined in new Surviving Sepsis Guidelines. Significant advances have been made in improving blood culture media; as yet no molecular or antigen-based method has proven superior for the detection of bacteremia in terms of limit of detection. Several methods for rapid molecular identification of pathogens from blood cultures bottles are available and many more are on the diagnostic horizon. Ultimately, early intervention by molecular detection of bacteria and fungi directly from whole blood could provide the most patient benefit and contribute to tailored antibiotic coverage of the patient early on in the course of the disease. Although blood cultures remain as the best means of diagnosing bacteremia and candidemia, complementary testing with antigen tests, microbiologic investigations from other body sites, and histopathology can often aid in the diagnosis of disseminated disease, and application of emerging nucleic acid test methods and other new technology may greatly impact our ability to bacteremic and septic patients, particularly those who are immunocompromised.

Synthesis, antimicrobial and in vitro antitumor activities of a series of 1,2,3-thiadiazole and 1,2,3-selenadiazole derivatives

Three derivatives of substituted 1,2,3-thia- or 1,2,3-selenadiazole (4a–c) were prepared and characterized by different chemical techniques. These compounds were evaluated for their antimicrobial and antitumor activities. Compounds 4a (propenoxide derivative), 4b (carbaldehyde derivative), and 4c (benzene derivative) were active against the yeast-like fungi Candida albicans. Compound 4a was active against gram-negative Escherichia coli, and compound 4c was active against the gram-positive Staphylococcus aureus. For the antitumor activity, both compounds 4b and 4c were active against all tested tumor cell lines, namely, SW480, HCT116, C32, MV3, HMT3522, and MCF-7. The activity of compound 4c was greater than that of compound 4b and more than that of the reference antitumor 5-flourouracil against the SW480, HCT116, and MCF-7 tumor cell lines. In conclusion, a number of the prepared 1,2,3-thia- or 1,2,3-selenadiazole compounds showed promising antifungal, antibacterial, and in vitro antitumor activities. Further investigations are required to explore the mechanism by which active compound are inducing their cytotoxicity.

Clinical efficacy of tigecycline used as monotherapy or in combination regimens for complicated infections with documented involvement of multiresistant bacteria

INTRODUCTION

Tigecycline is an established treatment option for infections with multiresistant bacteria (MRB). It retains activity against many strains with limited susceptibility to other antibiotics. Efficacy and safety of tigecycline as monotherapy or in combination regimens were investigated in a prospective noninterventional study involving 1,025 severely ill patients in clinical routine at 137 German hospitals.

MATERIALS AND METHODS

Data on the full population have been published; our present analysis focuses on infections caused by MRB. The study population included patients with complicated infections, high disease severity (APACHE II > 15: 65 %) and high MRB prevalence. Most patients had comorbidities, including cardiovascular disease, renal insufficiency, and/or diabetes mellitus. Treatment success was defined as cure/improvement without requirement of further antibiotic therapy.

RESULTS

Pathogens isolated from 215 evaluable patients with documented MRB infections included 132 methicillin-resistant Staphylococcus aureus (MRSA), 42 vancomycin-resistant Enterococci (VRE) and 67 Gram-negative extended beta-lactamase (ESBL) producers. Of the MRB subpopulation, 140 patients received tigecycline monotherapy, 75 were treated with combination regimens. High overall clinical success rates were recorded for MRB infections treated with tigecycline alone (94 %) or in combinations (88 %); in detail intraabdominal infections (monotherapy: 90 %; combinations: 93 %), skin/soft tissue infections (93; 100 %), community-acquired pneumonia (100; 100 %), hospital-acquired pneumonia (94,7; 72,7 %), diabetic foot infections (89; 33 %), blood stream infections (100; 100 %) and multiple-site infections (92; 71 %).

CONCLUSIONS

Tigecycline achieved high clinical success rates in patients with documented infections involving MRB strains despite high disease severity. These results add to the evidence indicating that tigecycline is a valuable therapeutic option for complicated infections in severely ill patients with a high likelihood of multidrug-resistant pathogen involvement.