Carlo Mancini

Klebsiella pneumoniae ST258 producing KPC-3 identified in Italy carries novel plasmids and OmpK36/OmpK35 porin variants

ABSTRACT A carbapenemase-resistant Klebsiella pneumoniae strain, clone ST258 producing KPC-3, was fully characterized. The entire plasmid content was investigated, thereby identifying plasmids of the IncFIIk (two of them similar to pKPQIL and pKPN3, respectively), IncX, and ColE types, carrying a formidable set of resistance genes against toxic compounds, metals, and antimicrobial drugs and a novel iron(III) uptake system.

Molecular Epidemiology of Escherichia coli Producing Extended-Spectrum β-Lactamases Isolated in Rome, Italy

ABSTRACT Escherichia coli strains producing extended-spectrum β-lactamases (ESBLs) are a major problem in many different hospitals worldwide, causing outbreaks as well as sporadic infections. The prevalence of Escherichia coli ESBL producers was analyzed in a surveillance study performed on the population attending the Policlinico Umberto I, the largest university hospital in Rome, Italy. We also investigated genotypes, pathogenicity islands, and plasmids in the ESBL-positive E. coli isolates as further markers that are useful in describing the epidemiology of the infections. In this survey, 163 nonreplicate isolates of Escherichia coli were isolated from patients from 86 different wards, and 28 were confirmed as ESBL producers. A high prevalence (26/28) of CTX-M-15 producers was observed within the bacterial population circulating in this hospital, and the dissemination of this genetic trait was associated with the spread of related strains; however, these do not have the characteristics of a single epidemic clone spreading. The dissemination was also linked to horizontal transfer among the prevalent E. coli genotypes of multireplicon plasmids showing FIA, FIB, and FII replicons in various combinations, which are well adapted to the E. coli species. The analysis of related bacteria suggests a probable interpatient transmission occurring in several wards, causing small outbreaks.

An Ertapenem-Resistant Extended-Spectrum-β-Lactamase-Producing Klebsiella pneumoniae Clone Carries a Novel OmpK36 Porin Variant

ABSTRACT Carbapenem-resistant Klebsiella pneumoniae caused an outbreak in a hospital in Rome, Italy. The clinical isolates were tested by antimicrobial susceptibility testing, pulsed-field gel electrophoresis, multilocus sequence typing, plasmid typing, and β-lactamase identification. The OmpK35 and OmpK36 porins were analyzed by SDS-PAGE, and their genes were amplified and sequenced. Complementation experiments were performed using a recombinant unrelated ompK36 gene. An ertapenem-resistant and imipenem- and meropenem-susceptible clone was identified and assigned to the sequence type 37 lineage by MLST; it carried SHV-12 and CTX-M-15 ESBLs, did not produce the OmpK35 due to a nonsense mutation, and expressed a novel OmpK36 variant (OmpK36V). This variant showed two additional amino acids located within the L3 internal loop, one of the highly conserved domains of the protein. Two isolates of the same clone also exhibited resistance to imipenem and meropenem, due to the loss of OmpK36 expression by a nonsense mutation occurring in the ompK36V variant gene. These were the first carbapenem-resistant K. pneumoniae isolates identified within the hospital. Screening for the ompK36V gene of unrelated K. pneumoniae isolates derived from patients from 2006 to 2009 demonstrated the high frequency of this gene variant as well as its association with ertapenem resistance, reduced susceptibility to meropenem, and susceptibility to imipenem.

Serum-Mediated Enhancement of TNF-α Release by Human Monocytes Stimulated with the Yeast Form of Candida albicans

The role of serum in the production of tumor necrosis factor-alpha (TNF-alpha) by human monocytes stimulated with yeast-form Candida albicans was studied. Pre-exposure of C. albicans to human pooled serum enhanced both TNF-alpha mRNA and cytokine secretion compared with C. albicans preincubated with medium only. Serum factors involved were >30 kDa, were efficiently inhibited by D-mannose, and recognized both Ca++-dependent and -independent pathways. Preincubation of yeasts with rabbit mannose-binding protein (MBP) resulted in dose-related enhancement of TNF-alpha secretion, through a Ca++-dependent pathway inhibited by D-mannose. TNF-alpha levels were similarly induced in C. albicans preincubated with vitronectin and with serum. Ca++ depletion did not affect cytokine release, while D-mannose supplementation displayed inhibition. The latter effect was abolished after Ca++ depletion. These data call for an involvement of both MBP and vitronectin in the serum-mediated enhancement of TNF-alpha release upon stimulation of monocytes with yeast forms of C. albicans.

Retrospective case-control analysis of patients with staphylococcal infections receiving daptomycin or glycopeptide therapy

Glycopeptides have been considered the antimicrobials of choice for serious meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-resistant coagulase-negative staphylococci (MR-CoNS) infections for several years. Daptomycin is a new option for the treatment of these infections, including those exhibiting reduced susceptibility to glycopeptides. The aim of this study was to compare glycopeptides and daptomycin for the treatment of infections caused by MRSA or MR-CoNS. Data for 106 patients with bloodstream infections (bacteraemia or infective endocarditis) or skin and soft-tissue infections (SSTIs) were retrospectively reviewed, of which 43 were treated with daptomycin (DAP group) and 63 were treated with vancomycin or teicoplanin (GLYCO group). Patients included in the two comparison groups were homogeneous in terms of age, risk factors and clinical severity. Aetiology was mainly represented by MRSA in both groups, followed by various species of MR-CoNS. Daptomycin was used more frequently in patients with central venous catheter-associated bacteraemia or pacemaker-associated infection. Patients with SSTIs included in the GLYCO group had a longer mean duration of antibiotic therapy (18.2 days vs. 14.6 days; P=0.009) and a longer mean length of hospital stay (28.2 days vs. 19.6 days; P=0.01) compared with those included in the DAP group. A longer mean duration of antibiotic therapy was also observed in patients with bloodstream infections receiving glycopeptide therapy (25.6 days vs. 18 days; P=0.004). In conclusion, the good clinical efficacy of daptomycin is associated with a more rapid resolution of the clinical syndrome and a reduced length of hospitalisation. This latter aspect may have important pharmacoeconomic implications, promoting the use of daptomycin in the clinical setting.

Surveillance and infection control in an intensive care unit

OBJECTIVE To evaluate the effect of an infection control program on the incidence of hospital-acquired infection (HAI) and associated mortality. DESIGN Prospective study. SETTING A 2000-bed, university-affiliated hospital in Italy. PATIENTS All patients admitted to the general intensive care unit (ICU) for more than 48 hours between January 2000 and December 2001. METHODS The infection control team (ICT) collected data on the following from all patients: demographics, origin, diagnosis, severity score, underlying diseases, invasive procedures, HAI, isolated microorganisms, and antibiotic susceptibility. INTERVENTIONS Regular ICT surveillance meetings were held with ICU personnel. Criteria for invasive procedures, particularly central venous catheters (CVCs), were modified. ICU care was restricted to a team of specialist physicians and nurses and ICU antimicrobial therapy policies were modified. RESULTS Five hundred thirty-seven patients were included in the study (279 during 2000 and 258 in 2001). Between 2000 and 2001, CVC exposure (82.8% vs 71.3%; P < .05) and mechanical ventilation duration (11.2 vs 9.6 days) decreased. The HAI rate decreased from 28.7% in 2000 to 21.3% in 2001 (P < .05). The crude mortality rate decreased from 41.2% in 2000 to 32.9% in 2001 (P < .05). The most commonly isolated microorganisms were nonfermentative gram-negative organisms and staphylococci (particularly MRSA). Mortality was associated with infection (relative risk, 2.11; 95% confidence interval, 1.72-2.59; P < .05). CONCLUSION Routine surveillance for HAI, coupled with new measures to prevent infections and a revised policy for antimicrobial therapy, was associated with a reduction in ICU HAls and mortality.

Monitoring for cytomegalovirus infection in organ transplant recipients: Analysis of pp65 antigen, DNA and late mRNA in peripheral blood leukocytes

The use of sensitive and specific methods for rapid and reliable diagnosis is required due to the considerable impact of human cytomegalovirus (HCMV) in organ transplant recipients. For this purpose the demonstration of the presence of viral antigens in peripheral blood leukocytes (PMNLs) and of viral nucleic acids in the same cells or in sera would seem to be of valid support. The present study was designed to test pp65 antigen, HCMV DNA and HCMV late mRNA in order to provide clinical information for the management of the infection. Fifty solid organ recipients were monitored for six months after transplant. The data obtained from the various tests were analysed from the first evidence of HCMV infection revealed by positive antigenaemia and/or DNA‐polymerase chain reaction (PCR). In 3 asymptomatic and in 7 symptomatic patients, PCR became positive 1–2 weeks before antigenaemia but PCR did not discriminate the clinical evolution of HCMV infection. The antigenaemia test well correlated to the development of viral infection being positive in all symptomatics and in 31, 2% of asymptomatics. The antigenic load >100/2 × 105 positive cells was always associated with clinical signs of illness. The detection of late mRNA was more indicative of the virus replicative status in the follow‐up of patients treated with ganciclovir. In some cases there was evidence, prior to the other two tests, the block of viral replication due to the antiviral therapy and in others the onset of HCMV infection relapse. J. Med. Virol. 53:189–195, 1997.

First Report of the Carbapenem-Hydrolyzing Oxacillinase OXA-58 in Acinetobacter baumannii Isolates in Italy

Emergence of Acinetobacter baumannii with resistance or reduced susceptibility to carbapenems has been reported worldwide ([4][1]). Acinetobacter may develop resistance to carbapenems through various mechanisms, including decreased permeability, efflux pump overexpression, and production of

Inhibition of in vitro proliferation of Epstein Barr virus infected B cells by an antisense oligodeoxynucleotide targeted against EBV latent membrane protein LMP1

Inhibition of in vitro proliferation of Epstein Barr Virus infected B cells by an antisense oligodeoxynucleotide targeted against EBV latent membrane protein LMP1

Invasive Pulmonary Aspergillosis in Non-Neutropenic Patients: Analysis of a 14-Month Prospective Clinical Experience

Abstract Invasive pulmonary aspergillosis (IPA) is one of the major causes of morbidity and mortality in severely immunocompromised patients, but recently several authors have reported the occurrence of IPA in liver cirrhosis, chronic obstructive pulmonary disease (COPD) patients, most of whom, but not all, were receiving steroid treatment, with a very high mortality rate. The detection of galactomannan performed in respiratory specimens is a new valuable test for the diagnosis of probable IPA, even in non-neutropenic high risk patients. Since the frequency and clinical impact of IPA in non-hematologic patients is not well known, it seemed rational to us to attempt a prospective study evaluating all patients hospitalized in a university hospital for whom an infectious Diseases consultation was required. this 14-month survey in our hospital, using recently recommended diagnostic criteria, seems to suggest an emerging role of IPA in these patients who may have a higher mortality rate than their neutropenic peers, and provides preliminary evidence that early diagnosis and prompt initiation of antifungal therapy may improve the ultimate outcome of their IPA.