BACKGROUND: Acinetobacter baumannii has emerged as a major cause of nosocomial outbreaks. It is particularly associated with nosocomial pneumonia and bloodstream infections in immunocompromised and debilitated patients with serious underlying pathologies. Over the last two decades, a remarkable rise in the rates of multidrug resistance to most antimicrobial agents that are active against A. baumannii has been noted worldwide. We evaluated the rates of antimicrobial resistance and changes in resistance over a 5-year period (2010–2014) in A. baumannii strains isolated from hospitalized patients in a tertiary Greek hospital. MATERIALS AND METHODS: Identification of A. baumannii was performed by standard biochemical methods and the Vitek 2 automated system, which was also used for susceptibility testing against 18 antibiotics: ampicillin/sulbactam, ticarcillin, ticarcillin/clavulanic acid, piperacillin, piperacillin/tazobactam, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, gentamicin, amikacin, tobramycin, ciprofloxacin, tetracycline, tigecycline, trimethoprim/sulfamethoxazole, and colistin. Interpretation of susceptibility results was based on the Clinical and Laboratory Standards Institute criteria, except for tigecycline, for which the Food and Drug Administration breakpoints were applied. Multidrug resistance was defined as resistance to ≥3 classes of antimicrobial agents. RESULTS: Overall 914 clinical isolates of A. baumannii were recovered from the intensive care unit (ICU) (n = 493), and medical (n = 252) and surgical (n = 169) wards. Only 4.9% of these isolates were fully susceptible to the antimicrobials tested, while 92.89% of them were multidrug resistant (MDR), i.e., resistant to ≥3 classes of antibiotics. ICU isolates were the most resistant followed by isolates from surgical and medical wards. The most effective antimicrobial agents were, in descending order: colistin, amikacin, trimethoprim/sulfamethoxazole, tigecycline, and tobramycin. Nevertheless, with the exception of colistin, no antibiotic was associated with a susceptibility rate >40% for the entire study period. The most common phenotype showed resistance against ampicillin/sulbactam, cephalosporins, carbapenems, aminoglycosides, ciprofloxacin, and tigecycline. An extremely concerning increase in colistin-resistant isolates (7.9%) was noted in 2014, the most recent study year. CONCLUSION: The vast majority of A. baumannii clinical isolates in our hospital are MDR. The remaining therapeutic options for critically ill patients who suffer from MDR A. baumannii infections are severely limited, with A. baumannii beginning to develop resistance even against colistin. Scrupulous application of infection control practices should be implemented in every hospital unit. Lastly, given the lack of available therapeutic options for MDR A. baumannii infections, well-controlled clinical trials of combinations of existing antibiotics are clearly needed.
Acinetobacter baumannii* ; Acinetobacter* ; Amikacin ; Aminoglycosides ; Anti-Bacterial Agents ; Anti-Infective Agents ; Carbapenems ; Cefotaxime ; Ceftazidime ; Cephalosporins ; Ciprofloxacin ; Colistin ; Critical Illness ; Disease Outbreaks ; Drug Resistance, Multiple ; Gentamicins ; Hospital Units ; Humans ; Imipenem ; Infection Control ; Intensive Care Units ; Pathology ; Phenotype ; Piperacillin ; Pneumonia ; Tetracycline ; Ticarcillin ; Tobramycin ; United States Food and Drug Administration

BACKGROUND: This study aimed to evaluate the epidemiology, clinical and microbiological features, treatment, and outcomes of infective endocarditis (IE) on the island of Crete, a region with high levels of antimicrobial resistance. MATERIALS AND METHODS: Medical records of all hospitalized patients diagnosed with IE at the University Hospital of Heraklion, Crete, Greece, from 1995 to 2015, were retrospectively reviewed. Patients who met the modified Duke's criteria for definite or possible IE were included. RESULTS: A total of 82 IE patients (median age 67 [range 21–86] years) were included. Most patients suffered from left-sided IE (94%), while most cases of infection occurred in native valves (53.6%). Systemic inflammatory response syndrome criteria were lacking in almost half of the patient population. The leading causative microorganism was Staphylococcus aureus, isolated in 24 cases (29%), followed by Streptococcus spp. in 15 (18%) and Enterococcus spp. in 12 (14.5%). A number of rare and difficult to treat microorganisms had been identified, such as Gemella morbillorum in four cases (4.5%), Streptococcus lugdunensis in two (2.5%) and Streptococcus pneumoniae in one (1%). One patient was serologically positive for Coxiella burnetii (1%). All patients received empirical antimicrobial treatment, proven appropriate in 39 blood culture-positive patients (56.5%). Thirteen (16%) patients were classified as culture negative. Seven patients (8.5%) were surgically treated. In-hospital death occurred in 9 patients (11%). CONCLUSION: Changes in IE profile requires continuous epidemiological updates. Staphylococcus and Streptococcus spp. remain the most common etiologic agents. However, the presence of uncommon and/or difficult to treat pathogens raise concerns on the appropriate prophylaxis as well as empirical treatment.
Coxiella burnetii ; Endocarditis* ; Enterococcus ; Epidemiology* ; Gemella ; Greece* ; Humans ; Medical Records ; Retrospective Studies ; Staphylococcus ; Staphylococcus aureus ; Streptococcus ; Streptococcus pneumoniae ; Systemic Inflammatory Response Syndrome ; Treatment Outcome

BACKGROUND: This study aimed to evaluate the epidemiology, clinical and microbiological features, treatment, and outcomes of infective endocarditis (IE) on the island of Crete, a region with high levels of antimicrobial resistance. MATERIALS AND METHODS: Medical records of all hospitalized patients diagnosed with IE at the University Hospital of Heraklion, Crete, Greece, from 1995 to 2015, were retrospectively reviewed. Patients who met the modified Duke's criteria for definite or possible IE were included. RESULTS: A total of 82 IE patients (median age 67 [range 21–86] years) were included. Most patients suffered from left-sided IE (94%), while most cases of infection occurred in native valves (53.6%). Systemic inflammatory response syndrome criteria were lacking in almost half of the patient population. The leading causative microorganism was Staphylococcus aureus, isolated in 24 cases (29%), followed by Streptococcus spp. in 15 (18%) and Enterococcus spp. in 12 (14.5%). A number of rare and difficult to treat microorganisms had been identified, such as Gemella morbillorum in four cases (4.5%), Streptococcus lugdunensis in two (2.5%) and Streptococcus pneumoniae in one (1%). One patient was serologically positive for Coxiella burnetii (1%). All patients received empirical antimicrobial treatment, proven appropriate in 39 blood culture-positive patients (56.5%). Thirteen (16%) patients were classified as culture negative. Seven patients (8.5%) were surgically treated. In-hospital death occurred in 9 patients (11%). CONCLUSION: Changes in IE profile requires continuous epidemiological updates. Staphylococcus and Streptococcus spp. remain the most common etiologic agents. However, the presence of uncommon and/or difficult to treat pathogens raise concerns on the appropriate prophylaxis as well as empirical treatment.
Coxiella burnetii ; Endocarditis* ; Enterococcus ; Epidemiology* ; Gemella ; Greece* ; Humans ; Medical Records ; Retrospective Studies ; Staphylococcus ; Staphylococcus aureus ; Streptococcus ; Streptococcus pneumoniae ; Systemic Inflammatory Response Syndrome ; Treatment Outcome