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BACKGROUND: Vancomycin-resistant enterococci (VRE) have become a major cause of nosocomial infections. The increase of vancomycin-resistant Enterococcus faecium (VR-Efm) in an intensive care unit (ICU) of an Italian university hospital from 2003 through 2004, led us to evaluate the phenotypic and genetic features of these strains. The prevalence of different bacterial species in this ICU is described. The antibiotic resistance profiles of VR-Efm strains, their van-genotype and pulsed-field gel electrophoresis (PFGE) profiles were also analyzed. MATERIALS AND METHODS: From January 2003 to December 2004, VR-Efm strains were collected from several biological samples. Bacteria were identified using standard biochemical reactions and automated systems. Antibiotic susceptibility was evaluated by disk diffusion and microdilution methods. Resistance to glycopeptides was confirmed by the E test. Vancomycin-resistant genotypes (vanA, vanB) were identified by PCR. Strains were typed by PFGE. RESULTS: Fifty E. faecium strains were isolated from a total of 700 patients. Of these, 26 were vancomycin-resistant and were isolated from 26 different patients. We also found one strain with resistance to linezolid. The vanA genotype was identified in 20/26 strains and vanB in the remaining strains. A major pulsed-field cluster ("A") was identified. In this cluster, 14 strains were identified (A1-A14) and 25 out of 26 VR-Efm belonged to it. Only one strain showed a different pattern (strain type "B"). All isolates with the vanA genotype belonged to cluster "A", therefore five out of six isolates with the vanB genotype belonged to cluster A. The only strain with type B pattern was the vanB genotype. CONCLUSIONS: Isolation of VR-Efm was very frequent (52%) in our cohort of patients and the vanA genotype was the most frequent (77%). We found 25 out of 26 VR-E. faecium strains to be epidemiologically related by PFGE (cluster A). Strains with distinct genotypes shared closely related PFGE profiles. The occurrence of one major cluster among patients of a single unit indicated intra-facility VRE transmission.

Despite progress made in the control of post-operative infections, the incidence of surgical site infections (SSIs) is still high. An improper perioperative antibiotic use can expose patients to the risk of resistant microorganisms, and, in surgical obese patients, the drug dosage and infusion time are critical points. The aim of our study was to evaluate the effectiveness of ertapenem in the prophylaxis of SSIs in obese patients undergoing general or bariatric surgery. METHODS: A total of 63 obese patients, candidates for several surgical interventions, were enrolled and divided into two groups. Patients received antibiotic prophylaxis before surgery: the case group received venous infusion of ertapenem; the control group received standard prophylaxis. Serum samples were tested for antimicrobial activity against Gram-positive and Gram-negative bacteria. RESULTS: After single-dose ertapenem in obese patients, we registered in vitro activity of sera against the growth of non-extended beta lactamase (ESBL)-producing Escherichia coli, Proteus mirabilis, Citrobacter freundii, Enterobacter cloacae, and non-ESBL-producing Klebsiella pneumoniae. Moreover, methicillin-sensitive Staphylococcus aureus and Streptococcus viridans were also inhibited. We found in vivo efficacy according to clinical monitoring: at the weekly and monthly follow-ups, one patient in the case group and six patients in the control group presented superficial incisional SSIs. CONCLUSIONS: These preliminary results are suggestive of the efficacy of ertapenem in perioperative prophylaxis of SSIs in obese patients; however, they need to be confirmed by further investigations and more defined trials.

The aim of this study was to establish the identification ability of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for bacteria of Burkholderia cepacia complex (Bcc) and to compare these results with those obtained by a molecular method (PCR-RFLP). A total of 57 isolates was used in the study. Isolates were collected from 31 patients attending the Regional Cystic Fibrosis Unit from January 2001 to December 2005. For phenotypic identification, both automated and manual systems were used. Using mass spectrometry, we identified all 57 isolates, previously identified by molecular method. Of these, 28 isolates were identified as B. cenocepacia, although not differentiated further into lineages. Moreover, other isolates were identified as B. cepacia (12 isolates), B. stabilis (12 isolates), and B. vietnamiensis (5 isolates). Our data indicate a good correlation between the two approaches.

Background. Despite the introduction of screening bases intrapartum prophylaxis,Streptococcus agalactiaeis still an important etiological agent of perinatal infections. The increasing rate of resistance and the differences in resistance pattern among countries suggest that a program of surveillance at the institutional level is important in determining optimal prophylaxis. In contrast, knowledge on GBS epidemiology in Italy is limited, and no data are available in the Southern region of the country. We sought to determine the occurrence of resistance to macrolides and clindamycin of GBS isolates in pregnant and nonpregnant women.Methods. Between 2005 and 2008, 1346 vaginal and 810 rectovaginal swabs were obtained from pregnant and not-pregnant women.Results. The occurrence of macrolides and clindamycin resistance was 16.5% in 2005 increasing up to 69.9% in 2008. A high percentage of isolates was resistant to tetracycline through all the study period with no statistically significant annual.Conclusions. In our cohort, an increase ofin vitroresistance of GBS to macrolides and clindamycin is clearly evident. The discordance with reports from different countries emphasize the crucial role of microbiological methods in setting possible therapeutic strategies.

The aims of this study were to analyze carbapenem-resistance Acinetobacter baumannii isolates (CRAB) and their molecular epidemiology in an ICU of Southern Italy. Clinical outcomes and therapeutic management of patients are also described. The study was performed from January 2007 to October 2010. The presence of carbapenemases was determined by PCR. Strains were typed by PFGE. All A. baumannii isolates were carbapenem-resistant with imipenem MIC≥16 μg/mL. Molecular characterization showed the occurrence of a predominant clone. The most frequent infection by CRAB was ventilator-associated pneumonia; colistin was the drug of choice for this infection. The therapy was safe in all cases except in one where therapy was suspended due to the onset of acute renal failure. We documented the presence of CRAB in this ICU, besides the occurrence of a predominant clone, over all the study period. Despite the infection control procedures used, intra-facility A. baumannii transmission is evident as well as the significant capacity for long-term survival in the hospital environment.

Background Pseudomonas aeruginosa, a non-fermentative, gram-negative rod, is responsible for a wide variety of clinical syndromes in NICU patients, including sepsis, pneumonia, meningitis, diarrhea, conjunctivitis and skin infections. An increased number of infections and colonisations by P. aeruginosa has been observed in the neonatal intensive care unit (NICU) of our university hospital between 2005 and 2007. Methods Hand disinfection compliance before and after an educational programme on hand hygiene was evaluated. Identification of microrganisms was performed using conventional methods. Antibiotic susceptibility was evaluated by MIC microdilution. Genotyping was performed by PFGE analysis. Results The molecular epidemiology of Pseudomonas aeruginosa in the NICU of the Federico II University hospital (Naples, Italy) and the infection control measures adopted to stop the spreading of P. aeruginosa in the ward were described. From July 2005 to June 2007, P. aeruginosa was isolated from 135 neonates and caused severe infections in 11 of them. Macrorestriction analysis of clinical isolates from 90 neonates identified 20 distinct genotypes, one major PFGE type (A) being isolated from 48 patients and responsible for 4 infections in 4 of them, four other distinct recurrent genotypes being isolated in 6 to 4 patients. Seven environmental strains were isolated from the hand of a nurse and from three sinks on two occasions, two of these showing PFGE profiles A and G identical to two clinical isolates responsible for infection. The successful control of the outbreak was achieved through implementation of active surveillance of healthcare-associated infections in the ward together with environmental microbiological sampling and an intense educational programme on hand disinfection among the staff members. Conclusion P. aeruginosa infections in the NICU were caused by the cross-transmission of an epidemic clone in 4 neonates, and by the selection of sporadic clones in 7 others. An infection control programme that included active surveillance and strict adherence to hand disinfection policies was effective in controlling NICU-acquired infections and colonisations caused by P. aeruginosa.

Summary Objectives To investigate the prevalence of infections by Chryseobacterium in a cohort of cystic fibrosis (CF) patients, to assess the antimicrobial susceptibility of these strains, to examine their DNA fingerprinting and to evaluate some clinical outcomes of patients infected by these bacteria. Methods Patients (300) attending a Regional Cystic Fibrosis Unit were enrolled in this study over 4 years. Natural or induced sputum samples were processed for microscopic and cultural tests. For phenotypic identification, automated and manual systems were used. For chemosusceptibility test, an automatic broth microdilution test and a disk-diffusion test were used and strains underwent DNA fingerprinting by pulsed-field gel electrophoresis (PFGE). Results Thirty-five strains of Chryseobacterium were isolated from 22 patients. These strains showed a broad-spectrum antimicrobial resistance, with activity only for trimethoprim–sulfamethoxazole and quinolones. PFGE profiles of all isolates were generally heterogeneous, suggesting independent circulation. Conclusions This is the first report about clinical isolates of Chryseobacterium spp from CF patients in an Italian Centre. The infection by Chryseobacterium was not associated to a deterioration of pulmonary function and mortality: therefore, all patients infected by Chryseobacterium were co-infected by Pseudomonas aeruginosa and 3 of these were also co-infected by Burkholderia cepacia complex.

The aims of this study were to detect Burkholderia cepacia complex (Bcc) strains in a cohort of Cystic Fibrosis patients (n=276) and to characterize Bcc isolates by molecular techniques. The results showed that 11.23% of patients were infected by Bcc. Burkholderia cenocepacia lineage III-A was the most prevalent species (64.3%) and, of these, 10% was cblA positive and 50% esmR positive. Less than half of the strains were sensitive to ceftazidime, meropenem, piperacillin tazobactam, and trimethoprim-sulfamethoxazole. About half of the strains (41%) had homogeneous profiles, suggesting cross-transmission. The infection by B. cenocepacia was associated to a high rate of mortality (p=0.01).

Background Recent reports document an increasing incidence of new Gram-negative pathogens such as Stenotrophomonas maltophilia and Alcaligenes xylosoxidans isolated from patients with Cystic Fibrosis, along with an increase in common Gram-negative pathogens such as Pseudomonas aeruginosa and Burkholderia cepacia complex. Furthermore, the increase in multidrug-resistance of such organisms makes the therapeutic management of these patients more problematic. Therefore, careful isolation and identification, and accurate studies of susceptibility to antibiotics are critical for predicting the spread of strains, improving therapeutic measures and facilitating our understanding of the epidemiology of emerging pathogens. The first aim of this study was to determine the incidence and the prevalence of colonization by Gram-negative organisms isolated from respiratory samples of Cystic Fibrosis patients in the Regional Referral Cystic Fibrosis Centre of Naples; the second was to evaluate the spectrum of multidrug-resistance of these organisms. Methods Patients (n = 300) attending the Regional Cystic Fibrosis Unit were enrolled in this study over 3 years. Sputum was processed for microscopic tests and culture. An automated system, Phoenix (Becton Dickinson, Sparks, Maryland, USA), was used for phenotypic identification of all strains; the API 20 NE identification system (bioMérieux, Marcy l'Etoile, France) was used when the identification with the Phoenix system was inaccurate. A PCR-RFLP method was used to characterize the organisms in the Burkholderia cepacia complex. A chemosusceptibility test on microbroth dilutions (Phoenix) was used. Primary outcomes such as FEV1 were correlate with different pathogens. Results During the period of study, 40% of patients was infected by Pseudomonas aeruginosa, 7% by Burkholderia cepacia complex, 11% by Stenotrophomonas maltophilia and 7% by Alcaligenes xylosoxidans. Of the strains isolated, 460 were multidrug-resistant. Multiresistant were Pseudomonas aeruginosa and Burkholderia cepacia complex. Conclusion The results confirm previously reported data; in particular, they show an increase the isolation of non-fermentative Gram-negative bacteria in Cystic Fibrosis patients. They also demonstrate increased resistance to antibiotics. Beta-lactams are rarely effective, with exception of ceftazidime, which is the most efficacious agent against multiresistant strains. Aminoglycosides and quinolones are poorly efficacious.

BACKGROUND: Patients with chronic renal failure (CRF) often have dyspeptic symptoms and may develop peptic disease or digestive disorders leading to severe gastrointestinal complications. The primary aim of this study was to evaluate the prevalence of peptic lesions and Helicobacter pylori infection, and the severity of dyspeptic symptoms, in dyspeptic patients with and without CRF. Our secondary aim was to investigate whether uremic status may affect the diagnostic efficiency of the [13]C-urea breath test ([13]C-UBT). PATIENTS AND METHODS: We consecutively enrolled in the study 50 dyspeptic patients with chronic kidney failure (mean age 52 +/- 5 years), of whom 11 were on hemodialysis treatment (HD), and 93 subjects (mean age 54 +/- 7 years) with chronic dyspepsia and normal renal function (NRF). All patients completed an oriented and validated questionnaire scoring the severity of nine dyspeptic symptoms (i.e. epigastric pain, epigastric burning, postprandial fullness, early satiety, bloating, belching, nausea and vomiting) and underwent upper endoscopy with multiple bioptic sampling for rapid urease test and histological examination, [13]C-UBT and HpSA test. RESULTS: The prevalences of peptic lesions and H. pylori infection and mean symptom score were 74%, 52% and 3.5 +/- 3, respectively, in dyspeptic patients with CRF and 18%, 36% and 8 +/- 5, respectively, in dyspeptic patients with NRF. The diagnostic accuracy of [13]C-UBT with respect to histological diagnosis was 94% and 97% for dyspeptic patients with and without renal failure, respectively. CONCLUSIONS: 1) A high frequency of peptic lesions and low symptom scores were observed in uremic patients in spite of H. pylori infection; 2) uremic status did not affect the diagnostic accuracy of [13]C-UBT.

Aim of this study was to characterize isolates of Pseudomonas aeruginosa responsible for ventilator-associated pneumonia (VAP) in patients admitted to an ICU in order to evaluate a possible strain clonality. The study was performed from October 2004 to June 2005 in one Southern Italy ICU and 29 patients suspected of having VAP were enrolled. The etiology of VAP was established by quantitative cultures of endotracheal aspirations. Molecular characterization was carried out by PFGE. P. aeruginosa was responsible for 51% of all cases of VAP (15/29) and 12/15 strains were multi-drug resistant. High mortality (44.8%) was connected to this pathogen and evidence of strain clonality was found. The early identification of strain clonality and the application of infection control procedures are necessary to avoid the spread of pathogens such as P. aeruginosa involved in nosocomial infections.