The Evolving Epidemiology of Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Strains Isolated from Adults in Crete, Greece, 2009–2016 / 감염과화학요법

BACKGROUND: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009–2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). MATERIALS AND METHODS: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ≥2 non-β-lactam antimicrobials. RESULTS: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. CONCLUSION: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

Epidemiology, Microbiological and Clinical Features, Treatment, and Outcomes of Infective Endocarditis in Crete, Greece / 감염과화학요법

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.

The Evolving Epidemiology of Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Strains Isolated from Adults in Crete, Greece, 2009–2016 / 감염과화학요법

BACKGROUND: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009–2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). MATERIALS AND METHODS: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ≥2 non-β-lactam antimicrobials. RESULTS: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. CONCLUSION: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

Epidemiology, Microbiological and Clinical Features, Treatment, and Outcomes of Infective Endocarditis in Crete, Greece / 감염과화학요법

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.

A 5-year Surveillance Study on Antimicrobial Resistance of Acinetobacter baumannii Clinical Isolates from a Tertiary Greek Hospital / 감염과화학요법

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.

Susceptibility of Glycopeptide-Resistant Enterococci to Linezolid, Quinupristin/dalfopristin, Tigecycline and Daptomycin in a Tertiary Greek Hospital / 감염과화학요법

We investigated the antibiotic susceptibility of glycopeptide-resistant enterococci (GRE). Seventy consecutive GRE were tested. Sixty-two isolates were identified as Enterococcus faecium (88.6%), and 8 (11.4%) as Enterococcus faecalis. All strains were susceptible to linezolid and daptomycin, while 17.1% (12/70) and 11.4% (8/70) were resistant to quinupristin/dalfopristin (QD) and tigecycline, respectively. All E. faecalis isolates were resistant to QD, while 4 of 62 (6.5%) E. faecium isolates were resistant to QD. All E. faecalis isolates were susceptible to tigecycline, while 14.5% (9/62) E. faecium isolates were resistant. Continued surveillance of GRE antibiotic susceptibilities is important for combating these multi-resistant nosocomial pathogens.