Antimicrobial resistance and class 1 and 2 integrons in Escherichia coli from meat turkeys in Northern Italy.

This study is aimed at determining the antimicrobial resistance (AMR) and the presence of class 1 and 2 integrons in 48 avian pathogenic Escherichia coli (APEC) strains isolated from meat turkeys during three sequential production cycles. Thirty avian faecal E. coli (AFEC) strains from the first cycle were also analysed. Strains were tested for AMR against 25 antimicrobials by disk diffusion test and were screened for the presence of integrons and associated gene cassettes by polymerase chain reaction followed by sequencing. Genetic relatedness of isolates was established by pulsed-field gel electrophoresis. High levels of resistance were detected to tetracyclines, penicillins and sulphonamides in APEC and AFEC. Resistance to aminoglycosides, fluoroquinolones, cephalosporins and phenicols was variable, based on the antimicrobial drug and the isolate (APEC vs. AFEC). Full susceptibility to colistin was detected. Multidrug resistance of up to seven antimicrobial classes was exhibited by APEC (93.8%) and AFEC (100%). Nearly 44% of strains tested positive for class 1 and/or class 2 integrons containing the dfrA, aadA and sat2 genes, alone or in combination, coding for streptomycin/spectinomycin, trimethoprim and streptothricin resistance, respectively. The estX and orfF genes of unknown function were also detected. A significant association was found between the presence of integrons and the resistance to aminoglycosides and potentiated sulphonamides. The results of this study showed that AMR, multidrug resistance and class 1 and 2 integrons are widespread among pathogenic and commensal E. coli from Italian turkeys. More attention should be addressed to limit the use of antimicrobials in turkeys and the AMR of turkey E. coli.

HIV coreceptor tropism in paired plasma, peripheral blood mononuclear cell, and cerebrospinal fluid isolates from antiretroviral-naïve subjects.

A survey of HIV coreceptor usage in cerebrospinal fluid (CSF) samples, peripheral blood mononuclear cells (PBMCs), and plasma samples from naïve seropositive patients was conducted. One hundred patients were enrolled in this study. Of the 100 patients, 36 had a primary or recent infection (P-RI), 31 had an early chronic infection (>350 CD4 cells) (ECI), and 33 had a late chronic infection (LCI). All 3 compartments were sampled in a subset of 33 participants, while the remaining 67 patients provided plasma samples and PBMCs only. Seventy-seven patients harbored the R5 virus in plasma samples and had a significantly higher median and percentage of CD4(+) T cells than patients with X4 virus (437 and 281 cells/µl, respectively; P = 0.0086; 20.6% and 18.6%, respectively). The X4 strain was detected more frequently in patients with LCI than in patients with P-RI or ECI (39.3%, 19.4%, and 9.6%, respectively; P = 0.0063). PBMC and plasma tropism was concordant in 90 patients, and 73 had the R5 strain. Among patients with discordant results, 4 had the R5 virus in their plasma and the X4 virus in PBMCs; 6 showed the opposite profile. Plasma, PBMC, and CSF tropism determinations were concordant in 26/33 patients (21 patients had R5, and 5 had X4). The tropism was discordant in 5/33 patients, with the X4 virus in plasma and R5 in CSF; the HIV tropism in PBMCs was X4 in 3 patients. The remaining 2/33 patients had the R5 virus in plasma and PBMCs and the X4 virus in CSF; one of these patients had a P-RI. The discordant tropism in CSF and blood may have implications for chemokine (C-C motif) receptor 5 (CCR5) antagonist use in patients with limited response to antiretroviral therapy (ART) or in responding patients evaluated for simplification of treatment.

Molecular epidemiology of Enterococcus faecium isolates from an Italian hospital.

BACKGROUND: Outbreaks of vancomycin-resistant Enterococcus faecium (VRE) strains is an emerging problem worldwide. Even if still relatively uncommon in European hospitals, infections caused by VRE have also been increasing recently in this continent. METHODS: In this study, we characterized 50 consecutive VRE and 23 vancomycin-sensitive E. faecium (VSE) isolates collected in an Italian hospital. The presence of the esp gene and that of genes encoding resistance to glycopeptides was investigated by polymerase chain reaction (PCR). All of the isolates were typed by multi-locus sequence typing (MLST), and a selection of them also by pulsed-field gel electrophoresis (PFGE). RESULTS: We found that all of the VRE and 18 (78%) of the VSE strains belonged to the single clonal complex-17 (CC17). The most represented sequence type (ST) was ST78 (34% of the isolates). When further analyzed by PFGE, ST78 isolates were subdivided into five pulsotypes, four of them closely related. The strong association between the esp gene and CC17 was confirmed. Interestingly, such an association was higher among vancomycin-resistant isolates. Most of the esp-positive isolates (34/46, 74%) encoded Esp4, a rare variant of this protein characterized by the absence of A repeats. CONCLUSIONS: Our findings underscore the role of the CC17 lineage in the nosocomial spread of VRE and VSE, and its rapid local evolution, underscoring the need for programs designed to provide early detection in order to prevent its spreading among the nosocomial population.

Switching of inferred tropism caused by HIV during interruption of antiretroviral therapy.

After interruption of highly active antiretroviral therapy, 15 out of 53 patients with the X4 HIV strain had a significantly larger decrease in CD4(+) T cell count (P = 0.001) and shorter length of treatment interruption (P = 0.02) than patients with the R5 strain. At treatment resumption, HIV inferred tropism switched from the X4 strain to the R5 variant in 9 patients (60%). These patients had a prolonged length of treatment interruption compared to that of those who still carried the X4 strain.

Clustering and risk factors of methicillin-resistant Staphylococcus aureus carriage in two Italian long-term care facilities.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a well-recognized agent of health care-associated infections in long-term care facilities, but few data about the circulation of MRSA in this setting in Italy are available. The aim of the study is to determine the prevalence and risk factors for MRSA carriage in nursing home residents in Vicenza (northeastern Italy). PATIENTS AND METHODS: A point prevalence survey was conducted in two long-term care facilities (subdivided into 15 wards) from 12 June 2006 to 6 July 2006. Anterior nasal swabs were obtained from residents and laboratory screening for MRSA was performed; full antibiotic susceptibility was assessed in MRSA isolates. Macrorestriction analysis of chromosomal DNA was carried out by pulsed field gel electrophoresis (PFGE). For each subject, demographic data, length of stay, dependency, cognitive function, presence of medical devices, comorbidities, current and previous antibiotic treatment, previous hospital admission and presence of infection were assessed on the day of sample collection. Factors that were found to be significantly associated with MRSA carriage at univariate analysis were introduced into multilevel logistic regression models in order to estimate the odds ratios (OR) with 95% confidence intervals (CI) for the risk of MRSA colonization, taking into account the clustering of patients within wards. RESULTS: Nasal swabs were obtained in 551 subjects; overall 43 MRSA carriers were detected (7.8%; CI = 5.7-10.4%). The rate of nasal carriers was very similar in the two institutions, and varied from 0% (0/36) to 18% (7/39) between wards. Only two out of 15 wards were found to have no MRSA carriers; overall, three pairs of colonized roommates were detected. Upon multilevel logistic regression, the risk of MRSA carriage was increased in patients with cancer (OR = 6.4; CI = 2.5-16.4), in those that had undergone recent hospitalization (OR = 2.2; CI = 1.0-4.4), and it reached OR = 4.0 (CI = 1.7-9.9) in those with three or more antibiotic treatments in the previous year; about 10% of the variability in MRSA carriage could be attributed to differences between wards. Pulsed field gel electrophoresis analysis permitted the definition of six clusters; two of these comprised 78.6% of the studied isolates and were quite similar, with one being more strongly represented among subjects hospitalized in the previous 12 months. All of the MRSA strains were resistant to ciprofloxacine; nevertheless, the majority were susceptible to most other non-betalactam antibiotics. CONCLUSION: The study suggests that nursing homes are a significant reservoir for MRSA. Statistical and PFGE analyses indicate a scenario where MRSA seems to be endemic and individual risk factors, namely recent hospitalizations and repeated antibiotic treatments, play a major role in the selection of drug-resistant organisms. Infection control measures should be coordinated among different health care settings, and the appropriate use of antibiotics has emerged as an important issue for improving the quality of care.

Detection of hepatitis C virus in an exhumed body identified the origin of a nosocomial transmission that caused multiple fatal diseases.

BACKGROUND: Medico-legal conflicts arise when it is difficult to prove the cause of nosocomial infections. AIM: To report an outbreak of patient-to-patient transmission of hepatitis C virus (HCV) through the repeated use of a multi-dose saline flask during the rinsing of central venous catheters. METHODS: Blood samples were taken from each patient for the comparative analysis of their HCV RNA strains. No samples were available for one patient who died before the investigation started. Despite the known lability of HCV RNA, the body was exhumed four months after burial and postmortem samples were collected. HCV RNA was extracted successfully from liver and spleen samples. Genotyping of all the HCV strains was performed by sequence analysis of the 5'NC untranslated region, the E1 core conserved region and the E1/E2 hypervariable region. FINDINGS: Forensic investigators retraced the route used by two ward nurses, when saline catheter flushes were given to 14 patients with each nurse administering to seven patients. The comparative phylogenetic analysis of all case strains identified the deceased patient as the source of contamination to five patients. CONCLUSIONS: This study highlights the value of sequence analysis as a tool for solving medico-legal conflicts. The High Court of Justice found that a health worker's re-use of a contaminated needle resulted in the nosocomial transmission of HCV.

Molecular analysis of vanA enterococci isolated from humans and animals in northeastern Italy.

A total of 53 vancomycin-resistant vanA-positive enterococci isolates from poultry farms (17 Enterococcus faecium; 8 Enterococcus durans) and from different hospitals (23 E. faecium; 5 Enterococcus faecalis) in northeastern Italy were compared on the basis of their antibiotic susceptibilities, their SmaI pulsed-field gel electrophoresis (PFGE) patterns, and the organization of their Tn1546-related elements. Ampicillin resistance was similar in both groups of isolates (52 and 60.7%, respectively), whereas human strains were more resistant to high-level gentamicin and streptomycin. A total of 52% of animal strains and 60% of human strains were resistant to tetracycline, and 56% and 46.4% to quinupristin/dalfopristin, respectively. In E. faecium and E. durans animal isolates, nine and six distinct PFGE patterns, respectively, were found: in two instances indistinguishable isolates were found from different farms. In E. faecium and E. faecalis human isolates, nine and six distinct PFGE patterns, respectively, were found; among E. faecium strains, 12 were identical or closely related and were isolates from the same hospital. Elements mediating vanA-glycopeptide resistance were characterized by PCR with primers that amplified 10 overlapping fragments of Tn1546. A total of 84.6% of animal strains and 64.2% of human strains contained elements indistinguishable from the prototype Tn1546. In addition, nine different types were identified, but none was common to animal and human strains.

A new factor X defect (factor X Padua 3): a compound heterozygous between true deficiency (Gly(380)-->Arg) and an abnormality (Ser(334)-->Pro).

We report a novel mutation in Factor X (FX) gene which results in a phenotype without any bleeding tendency. The proband has been found to be a compound heterozygote between a novel FX true deficiency (Gly(380)-->Arg) and a previously reported dysfunctional mutation Ser(334)-->Pro (FX Marsiglia). Prothrombin time (PT) and partial thromboplastin time (PTT) were moderately prolonged and were fully corrected by the addition of normal serum. Her FX activity level varied between 8% and 19% of normal according to the method used whereas the FX antigen level was 40% of the normal control value. All the exons and intron/exon junctions of the FX gene were studied using a combined approach of polymerase chain reaction and conformation sensitive gel electrophoresis. A transversion G to A in exon 8 resulting in the replacement of Gly380 by Arg was found in the proband, in the father and in a proband's brother, whereas heterozygous FX Marsiglia was present in the proband's mother and her sister. Gly380 is strictly linked to Ser379, a component of the catalytic triad. The substitution of Gly for Arg causes the introduction of a large charged amino acid which could affect the catalytic function of FX leading to secretion problem, accounting for the cross-reactive material (CRM) negative phenotype.