Epidemiology of skin and soft tissue pathogens circulating in Liguria in 2011

This study was conduced during March-May 2011 with the collaboration of 4 clinical microbiology laboratories evenly distibuited across the Ligurian area to identify the most frequent pahogens isolates from skin and soft tissue infections and to evaluate their antibiotic susceptibility patterns. Overall, 213 consecutive, non duplicate strains were collected and sent to the coordinating laboratory.The most rappresented pathogens were: S. aureus (35.7%), P. aeruginosa (14%), E. coli (12.7%), Staphylococcus coaugulase negative (6.6%) and Enterococcus spp. (4.7%). The data indicate an increase of Gram negative compared to previous years, S. aureus remains the most common pathogen.The methicillin resistance in S. aureus was 43.4% and no one Enterococcus spp. resistant to vancomicin was found

Epidemiological study of pathogens isolated from blood in Liguria during 2011

Objectives. An epidemiological study addressed to identify the most represented pathogens isolated from blood and to evaluate their antibiotic susceptibility patterns, was conducted. Methods. Five clinical microbiology laboratories, homogenously distributed in Liguria, were required to collected all consecutive non-duplicates strains isolated from blood cultures during March 2011 to May 2011. the strains were sent to the reference laboratory (Section of Microbiology, DISC, University of Genoa, Italy). Results. A total of 159 microorganisms were enrolled, including 81 Gram positive, 69 Gram negative and 9 fungi.The most represented pathogens were: Escherichia coli (35), Staphylococcus aureus (26), S. epidermidis (20), S. hominis (10). Samples were collected mainly from medicine (59 isolates).Among the staphylococci, the most active molecules were: vancomycin (100% of susceptible strains), teicoplanin (93.4%), trimethoprim-sulfamethoxazole (83.8%) and tobramycin (61.6%). Enterococci showed rates of resistance to vancomycin of 25%. Enterobacteriaceae exhibited resistance to ampicillin (76.9%), ceftriaxone (44.4%), ciprofloxacin (43.3%), trimethoprim-sulfamethoxazole (36.6%) and ceftazidime (32.2%). Conclusions. The data show a higher incidence of Gram positive (51%) in comparison to Gram negative (43.4%). Gram-positive strains showed a high resistance level to fluoroquinolones (92.3%) while Gram-negative resulted resistant to ceftriaxone (44.4%) and fluoroquinolone (43.3%)

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

Staphylococcus aureus catalasi-negativo meticillino resistente

In this work we report the isolation of a catalase-negative Staphylococcus aureus from a CVC and related wound swab.The susceptibility tests showed that the strain was methicillin resistant

Central Venous Catheter (CVC) related infections: a local retrospective study

Background. Central venous catheter (CVC) related infection is associated with significant increases in morbidity, mortality, and health care cost.This local surveillance study was carry out to monitor the frequency of occurrence of CVC-related blood stream infections. Materials and methods. During the period January – December 2005, 226 CVC specimens were analyzed (quantitative method) and microrganism identification from positive samples was performed by Vitek II. In 53 patients it was possible to compare quantitative results with those obtained from blood cultures. Results. Positive CVC samples were 125 (55%) and 130 microrganisms were isolated: 109 Gram-positives (84%), 4 Gram-negatives (3%), and 17 mycetes (13%). Among pathogens collected simultaneously from CVC and blood samples, the most frequently isolated were Staphylococcus spp. (30% coagulase-negative staphylococci and 20%. S. aureus) and Candida spp. (45%). In the group of patients that presented positive CVC and negative blood samples the most frequently recovered microrganisms were staphylococci. Many isolates (33%) were polymicrobial. Conclusions. Catheter-related infections occurred in those patients who presented the same pathogen in both CVC and blood cultures. These infections were principally caused by staphylococci and Candida spp. On the contrary, a possible CVC contamination could be suspected when positive CVC and negative blood cultures were found

Evaluation of the HB&L system for the culture of prosthetic and osteoarticular origin samples

Prosthetic and osteoarticular infections represent a complex condition to diagnose and resolve. In both cases, the eradication of microorganisms is difficult because of anatomical and physiological characteristics of the site of infection (bone).The best strategy for an effective pharmacological treatment is based on an early diagnosis confirmed by microbiological testing of bone, periprosthetic tissue or removed prostheses, to support clinicians to undertake prolonged targeted therapy. The purpose of this paper is to assess the clinical correlation between the results of the cultures performed with automated HB&L (ALIFAX) system compared to the result of traditional methods. HB&L is a system to perform bacterial cultures, susceptibility and direct P.A.R. tests on biological materials based on detection of bacteria and fungi by laser light-scattering kinetics in liquid culture medium at 37°C. Samples get to laboratory are inoculated in rich broth and placed in the incubator. The next day are processed accordin to the following protocol: 500 ml of the broth are transferred in the vial of the instrument and 200 ml of supplement DEB for fastidious organisms are added.The cultures are incubated for 360 minutes in the same time PAR test (antimicrobial residual power) is determined. In the first half of 2009 418 samples collected from prostheses and osteoarticular infections from 118 patients were analyzed.The tests showed 304 negative and 114 positive samples (27.30%) from which were isolated Gram negative (17.5%) and Gram positive (82.5%) bacteria. Gram positive included 38.3% S. aureus, 33% coagulase negative Staphylococci and 26.6% Enterococci. Preliminary data obtained by the HB&L system for the culture of tissue sample, as well as the improvement of surgical techniques have led to a significant increase in correlation with the clinical data compared to traditional microbiological analysis

Indagine epidemiologica locale dell’eziologia delle infezioni delle vie urinarie (IVU) nosocomiali e comunitarie e dell’antibiotico-sensibilità degli uropatogeni.

Background: Urinary tract infections (UTIs) are common infectious diseases that can be associated with substantial morbidity. During the last decade, resistance to ampicillin and co-trimoxazole has increased in Escherichia coli, the most common uropathogen, and recent reports have shown increasing resistance even to fluoroquinolones. The aim of this local surveillance study was to determine the distribution of bacterial strains isolated from outpatients and inpatients with UTIs and antibiotic susceptibility patterns to antimicrobial agents currently used in the treatment of pathogens causing these infections. Materials and methods: Between January and March 2006 a total of 1596 urine specimens, 968 from outpatients and 628 from inpatients, respectively, were recovered. Urinary pathogens isolated were 235, identification and antimicrobial susceptibility testing were performed by Vitek II.The following antimicrobial agents were tested: ampicillin, amoxicillin-clavulanic acid, ceftazidime, imipenem, co-trimoxazole, ciprofloxacin, gentamicin and nitrofurantoin. E test® method were used to study the production of extended spectrum beta-lactamases (ESBL). Results:The most frequent pathogen found was Escherichia coli (68.5%), followed by Klebsiella spp. (8.5%), Proteus mirabilis (7.6%), and Enterococcus spp. (6%). E. coli resistance rates less than 10% was observed for ceftazidime, imipenem and nitrofurantoin. In strains isolated from outpatients resistance to ampicillin and trimethoprim-sulfamethoxazole was 37% and 19%, respectively, and resistance to fluoroquinolones was about 20%. Resistance rates of E. coli was significantly higher in complicated nosocomial-acquired infection: ampicillin 53.6%, cotrimossazole 35.7% and ciprofloxacin 33.9%. ESBL producer strains were 7 E.coli (4.3%) and 6 Proteus spp. (33%). Conclusions: This study confirmed that E. coli and other Enterobacteriaceae are the predominant bacterial pathogens envolved in UTIs. Currently, the empirical use of co-trimoxazole and ampicillin is not recommended. Because of the increase in fluoroquinolones resistance among uropathogens patients who can benefit from these antimicrobial agents must be selected. Third-generation cephalosporins still have high sensitivity rates (although the the emergence of extended-spectrum beta-lactamase-producing enterobacterial should be taken into account). Urine culture and antimicrobial susceptibility testing is the “gold standard” for diagnosis of UTI and selection of appropriate treatment

Epidemiology of skin and soft tissue pathogens circulating in Liguria in 2011

This study was conduced during March-May 2011 with the collaboration of 4 clinical microbiology laboratories evenly distibuited across the Ligurian area to identify the most frequent pahogens isolates from skin and soft tissue infections and to evaluate their antibiotic susceptibility patterns. Overall, 213 consecutive, non duplicate strains were collected and sent to the coordinating laboratory.The most rappresented pathogens were: S. aureus (35.7%), P. aeruginosa (14%), E. coli (12.7%), Staphylococcus coaugulase negative (6.6%) and Enterococcus spp. (4.7%). The data indicate an increase of Gram negative compared to previous years, S. aureus remains the most common pathogen.The methicillin resistance in S. aureus was 43.4% and no one Enterococcus spp. resistant to vancomicin was found

Epidemiology of multi-resistance Gram negative pathogen circulating in Liguria and molecular characterization of different carbapenemases

This study was conducted during January-April 2010 with the collaboration of 7 clinical microbiology laboratories evenly distributed across the Ligurian area to identify the most frequent Gram negative species and to evaluate their antibiotic susceptibility patterns Overall, 110 consecutive multi-resistant non duplicate Gram negative isolates,were collected and sent to the coordinating laboratory (Sezione di Microbiologia del DISC, University of Genoa, Italy) together with susceptibility data obtained by routine methods. In addition, strains resistant to carbapenems were characterized by PCR. A total of 110 Gram negative multi-resistance strains were found, including 74 and 36 isolated from healthcare or nosocomial settings and community acquired infections, respectively. The most represented pathogens were: A. baumannii (38, 34.5%), E. coli (30, 27.2%), P. aeruginosa (29, 26.3%), K. pneumoniae (9, 8.2%) and P. mirabilis (4, 3.6%). A. baumannii were more frequently collected from healthcare settings or nosocomial samples, while the other strains were generally equally isolated from in- and out-patients. Amikacin was the most active molecule against E. coli and P. mirabilis (96,7% and 100% of susceptible stains respectively). Colistin was the only active molecule agains A. baumanii and P. aeruginosa (100% of susceptible strains). Against K. pneumoniae tigecycline and colistin were the most active molecules (100% of susceptible strains). Imipenem was the most active compound against E. coli and P. mirabilis (100% of susceptible strains). A large number (97.4%) of A. baumannii was resistant to imipenem. K. pneumoniae and P. aeruginosa showed rates of resistance of 88% and 34.4% respectively. A. baumannii, K. pneumoniae and P. aeruginosa isolates resistant to Imipenem, carried OXA-23, KPC and VIM carbapenemases.These data shown a significant spread of multidrug-resistant Gram negative bacteria in hospitals and in communities.The production of carbapenemase in A. baumannii, K. pneumoniae and P. aeruginosa is now an important phenomenon in our region

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