Epidemiological study of pathogens isolated from blood in Liguria (January-April 2010)

Objectives. An epidemiological study to identify the most represented pathogens isolated from blood and to evaluate their antibiotic susceptibility patterns, was conducted. Methods. Seven clinical microbiology laboratories, homogeneously distributed in the Ligurian area,were required to collected all consecutive non-duplicates strains isolated froom blood cultures during January 2010 to April 2010. The strains were sent to the reference laboratory (Sezione di Microbiologia del DISC, University of Genoa, Italy). Results. A total of 277 microorganisms were enrolled, including 155 Gram positive and 122 Gram negative.The most represented pathogens were: Escherichia coli (68), Staphylococcus aureus (57), Staphylococcus epidermidis (32), Staphylococcus hominis (17), Pseudomonas aeruginosa (15), Klebsiella pneumoniae (15), Enterococcus faecalis (11). Samples were collected mainly from medicine (66, 33.3%, of this number was determined by E. coli), intensive care units (33, 18.2% of this number consisted of S. epidermidis), surgery (24, 33.3% consisted of E. coli) and infectious diseases (20, of which S. aureus, E. coli and S. epidermidis equally represented 20.0%).Among the Staphylococci the most active molecules were: vancomycin and teicoplanin (100% of susceptible strains), chloramphenicol (92.3%) and trimethoprim-sulfamethoxazole (89.8%). Among the OXA-R Staphylococci (81/123, 65.9%) the most active molecules were: vancomycin and teicoplanin (100% of susceptible strains), chloramphenicol (93.8%) and trimethoprim-sulfamethoxazole (84.8%). Enterococci showed rates of resistance to vancomycin of 5.9%. Enterobacteriaceae exhibited resistance to ampicillin (77.5%), trimethoprim-sulfamethoxazole (42.6%), ciprofloxacin (41.2%), ceftriaxone (37.5%), ceftazidime (28.2%), cefepime (26.7%), cefoxitin (22.1%), piperacillintazobactam (20.4%), imipenem (4.7%) and amikacin (2.9%). The Gram negative non-Enterobacteriaceae showed rates of resistance of 100% to ceftriaxone, 81.3% to trimethoprim-sulfamethoxazole, 42.1% to ciprofloxacin and piperacillin-tazobactam, 33.3% to ceftazidime, 31.6% to cefepime, 27.8% to imipenem, 26.3 % to amikacin. Conclusions. The data show a higher incidence of Gram positive (56%) in comparison to Gram negative (44%).This confirms the high incidence of oxacillino-resistance in Staphylococci in our geographic area.Against Enterobacteriaceae rates of resistance were observed in excess of 20% for all drugs tested except imipenem (4.7%) and amikacin (2.9%). The proportion of imipenem-resistant isolates was constituted of strains of K. pneumoniae carbapenemase producers

Epidemiological study of pathogens collected from blood for a period of a year (2008-2009)

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Epidemiological study on distribution and antibiotic susceptibility patterns of Enterobacteriaceae and non-fermenting bacteria, isolated in Liguria and in a neighbouring area

Introduction. An epidemiological study addressed to identify gram-negative bacteria, isolated from laboratories in a Northern area of Italy, and their antibiotic resistance patterns was conducted. Methods. Twelve laboratories distributed on Ligurian territory or neighbouring areacollected all consecutive gram-negative isolates belonging to the Enterobacteriaceae family and non-fermenter group for 2 months and sent them to a reference laboratory. Results. A total of 1880 pathogens were collected, including 899 and 981 strains isolated from nosocomial- and community-acquired infections, respectively. Escherichia coli (63.3% of total) was the most frequently isolated pathogen followed by Pseudomonas aeruginosa (9.6%), Proteus mirabilis (8.9%) and Klebsiella pneumoniae (5.4%). Nosocomial samples were collected mainly from patients in general medicine wards (19.9%) and healthcare settings (14.1%). Urine was the most common clinical sample (79.9% of the total). Other samples were sputum and bronchoaspirates (8%), skin wounds including those from decubitus (5.3%) and blood (4.1%). E. coli and P. mirabilis were collected mainly from urinary tract infection while P. aeruginosa appears more involved in respiratory or other infections. Considering the resistance to representative classes of antibiotics, it was higher (%) for piperacillin-tazobactam in P. mirabilis (30.3), for ceftazidime in Enterobacter aerogenes (40.8) and in Providencia stuartii (40), for imipenem and amikacin in P. aeruginosa (16.2 and 13.7 respectively), for ciprofloxacin in P. stuartii (66.6) and in P. mirabilis (44.7) than in others bacteria. Conclusions. The increasing age of the population in general medical wards and healthcare settings is associated with urinary tract and bedsore infections. E. coli confirms its epidemiologic and pathogenic role, but P. mirabilis and P. aeruginosa are emerging as alternativechallenges

Epidemiological study of pathogens collected from blood for a period of a year (2008-2009)

Objectives. An epidemiological study, addressed to identify the pathogens isolated from blood, and their antibiotic susceptibility patterns, was conducted. Methods. 12 laboratories, homogeneously distributed in a Northern area of Italy, were required to collected all consecutive non-duplicated strains isolated from blood during February 2008 to February 2009 and sent them to the reference laboratory. Results. A total of 1092 microorganisms were collected, including 653 gram-positive, 385 gram-negative and 54 fungi. Escherichia coli 234, Staphylococcus epidermidis 205, S. aureus 142, S. hominis 87, Enterococcus faecalis 47, S. haemolyticus 33, Klebsiella pneumoniae 33, Pseudomonas aeruginosa 32, Candida albicans 28, Enterobacter cloacae 21 were the prevalent microrganisms found. Samples were collected mainly from medicine (255 strains), intensive care units (154), surgery (99), infectious diseases (93), paediatrics (62) and nephrology (62). Antibiotic resistance (in %) in staphylococci was 65.7 (methicillin), 33.5 (gentamicin), 61.8 (azithromycin), 59.6 (erythromycin), 45.2 (ciprofloxacin) 14.8 (chloramphenicol), 2.0 (teicoplanin), and 24.1 (trimethoprim-sulfamethoxazole) no vancomycin-resistant strain was found. Enterococci showed resistance to vancomycin (10.8), ampicillin (34.4), gentamycin (42.9), ciprofloxacin (42.2) teicoplanin (7.6), erythromycin (54.7) and chloramphenicol (17.5). Enterobacteriaceae exhibited resistance to ciprofloxacin(27.0), ampicillin (74.1), ceftazidime (15.8), cefoxitin (14.7), cefepime (13.3), ceftriaxone (15.0), both imipenem and amikacin (0.95), piperacillin-tazobactam (5.1) and trimethoprim-sulfamethoxazole (32.7). Non fermenting gram negative strains were found resistant to ciprofloxacin (27.3), ceftazidime (9.5), cefepime (14.6), ceftriaxone (81.6), both imipenem and amikacin (18.6), trimethoprim-sulfamethoxazole (65.2), and piperacillin-tazobactam (7.5). Conclusions.These data show a prevalent incidence of gram-positive (59.7 %) in comparison to gram-negative (35.3%) bacteria isolated from blood.A high percentage of methicillin-resistant staphylococci as well as ceftazidime-resistance among Enterobacteriaceae is also observed suggesting that this phenomenon requires periodically surveillance

Indagine sulla diffusione di stafilococchi resistenti alla meticillina in Liguria

Introduction. Staphylococcus aureus is a major opportunistic pathogen especially in nosocomial settings. An increasing proportion of strains has intrinsic resistance to methicillin (MRSA) and recent reports documented the emergence of MRSA also in the community.The aim of this study was to evaluate methicillin-resistance in Liguria. Methods. 767 isolates of Staphylococcus spp have been collected from 10 laboratories, including 508 S. aureus: 292 (57.5%) hospital-acquired, 188 (37%) community-acquired, and 28 (5.5%) from healthcare settings; 259 coagulase- negative staphylococci (CNS): (193 (74.5%) hospital-acquired, 56 (21.6%) community-acquired, and 10 (3.9%) healthcare settings. Susceptibility tests were carried out by the disk diffusion method (CLSI, 2006) using cefoxitin (CFX) (Oxoid, Milan). MRSA has been also evaluated by PBP2’ latex agglutination test (Oxoid, Milan) on 52 randomly selected S. aureus. Results. The data obtained indicated an incidence of MRSA in nosocomial settings up to 45.2%, while among the community-acquired isolates the percentage was 6.4%. With respect to CNS the figures were 61,8% and 10,6% for the nosocomial-and community-acquired organisms respectively. A 99% agreement between data of the coordinating centre and the various laboratories was found. Methicillin-resistance was confirmed in 52 S. aureus by PBP2’ latex agglutination test. Conclusions. Present findings indicate that MRSA in community in the Ligurian area exists and this phenomenon requires future surveillance