Outbreak of NDM-1-producing Enterobacteriaceae in northern Italy, July to August 2011

Between July 2011 and August 2011, the New Delhi metallo-beta-lactamase 1 (NDM-1) gene was detected in Klebsiella pneumoniae and Escherichia coli isolates obtained from six patients hospitalised in four healthcare facilities in northern Italy. The patient who had been hospitalised in New Delhi, India, from February to May 2011 and subsequently in the Bologna area, Italy, from May to July 2011, may have been the source of the outbreak. Our findings suggest ongoing spread of this carbapenem-resistance gene in Italy and highlight the need for intensive surveillance.

Outbreak of NDM-1-producing Enterobacteriaceae in northern Italy, July to August 2011

Between July 2011 and August 2011, the New Delhi metallo-beta-lactamase 1 (NDM-1) gene was detected in Klebsiella pneumoniae and Escherichia coli isolates obtained from six patients hospitalised in four healthcare facilities in northern Italy. The patient who had been hospitalised in New Delhi, India, from February to May 2011 and subsequently in the Bologna area, Italy, from May to July 2011, may have been the source of the outbreak. Our findings suggest ongoing spread of this carbapenem-resistance gene in Italy and highlight the need for intensive surveillance.

Imported cases of dengue virus infection: Emilia-Romagna, Italy, 2010

Dengue is a significant mosquito-borne infection in humans, and its worldwide prevalence is rapidly increasing. In 2010, 83 serum samples from febrile travellers returning from dengue-endemic countries to a region in north-eastern Italy, densely infested with Aedes albopictus, were analysed for dengue virus (DENV). DENV RNA was detected in 20.5% of patients. By RT-PCR, DENV serotypes 1 and 3 were the most common. DENV must be identified early in symptomatic travellers returning from high-risk countries, to prevent outbreaks where potential vectors exist.

Hepatitis C virus core antigen: analytical performances, correlation with viremia and potential applications of a quantitative, automated immunoassay

BACKGROUND

Testing for hepatitis C virus core antigen (HCV Ag) may represent a complementary tool to anti-HCV and HCV-RNA in the diagnosis and monitoring of HCV infection.

OBJECTIVE

To evaluate the performance characteristics of the automated Abbott ARCHITECT HCV Ag assay.

STUDY DESIGN

Five sites analyzed over 3000 routine serum samples from populations at different risk, comparing HCV Ag results with anti-HCV screening and supplemental assay results and with HCV-RNA.

RESULTS

The HCV Ag assay showed a specificity of 100%, a good precision (CV<10%) and excellent dilution linearity (r>0.999). The sensitivity (3 fmol/L) corresponds to 700-1100 IU/mL of HCV-RNA. A non-linear correlation with HCV-RNA was found: r=0.713 vs. Siemens bDNA (523 specimens), r=0.736 vs. Roche Cobas TaqMan (356 specimens) and r=0.870 vs. Abbott Real-Time PCR (273 specimens). HCV Ag quantitation was equally effective on different HCV genoypes (239 for genotype 1/1a/1b/1c, 108 for genotype 2/2a/2c, 86 for genotype 3/3a, 50 for genotype 4/4a/4c/4d). Testing of subjects at high risk for HCV and with potential or actual impairment of the immune system identified 2 cases negative for anti-HCV and positive for HCV Ag on 361 hemodialyzed (0.6%) and 7 cases on 97 (7.2%) among transplant recipients. HCV Ag positivity anticipated anti-HCV seroconversion in all three cases of acute hepatitis C.

CONCLUSIONS

HCV Ag may be used as reflex testing on anti-HCV positive individuals to confirm or exclude an active infection, and on subjects with acute hepatitis or belonging to high risk groups.

Cytomegalovirus-induced immunopathology and its clinical consequences

Human cytomegalovirus (CMV) is a ubiquitous DNA virus that causes severe disease in patients with immature or impaired immune systems. During active infection, CMV modulates host immunity, and CMV-infected patients often develop signs of immune dysfunction, such as immunosuppression and autoimmune phenomena. Furthermore, active viral infection has been observed in several autoimmune diseases, and case reports have linked primary CMV infection and the onset of autoimmune disorders. In addition, CMV infection promotes allograft rejection and graft-versus-host disease in solid organ and bone marrow transplant recipients, respectively, further implicating CMV in the genesis and maintenance of immunopathological phenomena. The mechanisms by which CMV could induce inhibition of host defense, inflammation, and autoimmunity are discussed, as is the treatment of virus-induced immunopathology with antivirals.

Rapid increase of carbapenemase-producing Klebsiella pneumoniae strains in a large Italian hospital: surveillance period 1 March - 30 September 2010

The first case of carbapenemase-producing Enterobacteriaceae in Italy was reported in 2009. We performed a study over a period of seven months in 2010 to survey the circulation of Klebsiella pneumoniae carbapenemases (KPC) ina 1,500-bed university hospital in northern Italy and report the presence and rapid increase of these multidrug-resistant bacteria. The results raise a major concern about these pathogens and demonstrate the urgent need for infection control and antibiotic stewardship programmes.

Rapid increase of carbapenemase-producing Klebsiella pneumoniae strains in a large Italian hospital: surveillance period 1 March – 30 September 2010

The first case of carbapenemase-producing Enterobacteriaceae in Italy was reported in 2009. We performed a study over a period of seven months in 2010 to survey the circulation of Klebsiella pneumoniae carbapenemases (KPC) in a 1,500-bed university hospital in northern Italy and report the presence and rapid increase of these multidrug-resistant bacteria. The results raise a major concern about these pathogens and demonstrate the urgent need for infection control and antibiotic stewardship programmes.

Absence of neuroinvasive disease in a liver transplant recipient who acquired West Nile virus (WNV) infection from the organ donor and who received WNV antibodies prophylactically

We describe the first case of West Nile virus (WNV) infection in Europe with transmission from donor to recipient following liver transplantation. The infection was detected in the recipient 3 days after transplantation, during the asymptomatic phase. We also report an innovative prophylactic strategy based on infusion of WNV hyperimmune plasma and gamma globulins that could be effective in preventing the appearance of a neuroinvasive disease.

Retrospective screening of solid organ donors in Italy, 2009, reveals unpredicted circulation of West Nile virus

Since the occurrence of West Nile virus (WNV) infection in humans in 2008 in Italy, concerns have been raised about the potential risks associated with solid organ transplantation (SOT). A nationwide retrospective survey showed that 1.2% of SOT donors in 2009 were WNV-seropositive and demonstrated that human WNV infection is distributed throughout several Italian regions. Transmission of WNV or other arboviruses through SOT is a possibility and risk assessment should be carried out before SOT to avoid infection through transplantation.

Monitoring cytomegalovirus T-cell immunity in small bowel/multivisceral transplant recipients

BACKGROUND

Cytomegalovirus (CMV) is a major cause of graft failure and posttransplantation mortality in intestinal/multivisceral transplantation. CMV infection exhibits a wide range of clinical manifestations from asymptomatic infection to severe CMV disease. STUDY'S PURPOSE: The purposes of this study were to assess the utility of measuring CMV-specific cellular immunity in bowel/multivisceral transplant recipients and to provide additional information on the risk of infection and development of CMV disease.

METHODS

We studied 10 bowel/multivisceral transplant recipients to investigate the kinetics of CMV infection using real-time polymerase chain reaction (on blood and biopsy tissue samples) and CMV-specific T-cell reconstitution by Enzyme-linked ImmunoSPOT Assay (ELISPOT) that enumerates Interferon-gamma-secreting CMV-specific T cells upon in vitro stimulation with viral antigens (pp65 and IE-1).

RESULTS

All patients were seropositive for CMV. According to the pattern of T-cell reconstitution occurring either within the first month after transplantation or later, patients were classified as early (n = 7) or late responders (n = 3). Clinically, early responder patients (3/7; 43%) experienced asymptomatic or mild CMV infections, whereas all late responders (3/3; 100%) developed moderate or severe CMV disease. A reduction in mean and peak CMV viral load was observed in early responders, whereas the onset time of infection did not differ significantly between early and late CMV responders.

CONCLUSIONS

A good and early reconstitution of CMV-specific T-cell immune responses after transplantation is a critical determinant in controlling CMV infections. Simultaneous monitoring of CMV infection and CMV-specific T-cell immunity predicts T-cell-mediated control of CMV infection.

Early and late virological monitoring of cytomegalovirus, Epstein-Barr virus, and human herpes virus 6 infections in small bowel/multivisceral transplant recipients

BACKGROUND

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) are the major causes of graft failure and posttransplantation mortality among small bowel and multivisceral transplantations (SB/MVT). Little is known about human herpes virus 6 (HHV-6) infections in transplant recipients.

STUDY PURPOSE

The purposes of this study were to analyze the clinical relevance of CMV, EBV, and HHV-6 infections after small bowel transplantation and to establish whether routine monitoring for HHV-6 infection should be recommended for the prevention of severe complications in this population.

METHODS

Ten adult patients were monitored based on CMV, EBV, and HHV6 DNA quantifications in blood and biopsy tissue samples. Three patients were monitored for at least 5 months (early period) and 7 patients were monitored for 1 to 5 years after transplantation (late period).

RESULTS

In the early period, despite prophylaxis all 3 patients developed symptomatic CMV infections: 1 fever/diarrhea, 1 enteritis and rejection, as well as 1 fever and pneumonia. Only 1 patient developed EBV and HHV-6 infections. The average time of onset of CMV infection was 3 months after transplantation and only 24 days for HHV6 infection. In the late period, of the 7 SB/MVT recipients only 1 developed an EBV infection at 2 years after transplantation. No CMV or HHV-6 infections were identified in any patient.

CONCLUSIONS

CMV infection is a major cause of organ disease and rejection in the early period after transplantation. EBV infection in adult recipients must be considered also in the late period, particularly in association with severe immunosuppression. Because HHV-6 infection occurs earlier than CMV/EBV, it may serve as an indicator for more intense virological surveillance.

Blood culture systems: rapid detection--how and why?

Bloodstream infections are associated with high morbidity and mortality. Blood culture is considered to be the most important tool in their diagnosis. In this study we compared standard blood culture with two different molecular techniques (Prove-it Sepsis and LightCycler SeptiFast M) to detect bacterial species and fungi in the blood of septic patients. Both methods showed significant agreement with the results obtained by blood culture. The results of these studies suggest that both the LightCycler SeptiFast and Prove-it Sepsis tests can be used for the rapid and specific diagnosis of bacteraemia and bloodstream infections. It is important, however, to emphasize that molecular methods cannot replace blood cultures, as the latter allow the evaluation of the antimicrobial susceptibility of isolated microbes.

Usutu virus infection in a patient who underwent orthotropic liver transplantation, Italy, August-September 2009

We report a case of Usutu virus (USUV)-related illness in a patient that underwent an orthotropic liver transplant (OLT). Post transplant, the patient developed clinical signs of a possible neuroinvasive disease with a significant loss of cerebral functions. USUV was isolated in Vero E6 cells from a plasma sample obtained immediately before the surgery, and USUV RNA was demonstrated by RT-PCR and sequencing. This report enlarges the panel of emerging mosquito-borne flavivirus-related disease in humans.

Usutu virus infection in a patient who underwent orthotropic liver transplantation, Italy, August-September 2009

We report a case of Usutu virus (USUV)-related illness in a patient that underwent an orthotropic liver transplant (OLT). Post transplant, the patient developed clinical signs of a possible neuroinvasive disease with a significant loss of cerebral functions. USUV was isolated in Vero E6 cells from a plasma sample obtained immediately before the surgery, and USUV RNA was demonstrated by RT-PCR and sequencing. This report enlarges the panel of emerging mosquito-borne flavivirus-related disease in humans.

Chikungunya: an emerging and spreading arthropod-borne viral disease

The virus causing Chikungunya disease was identified over 50 years ago; however, because the disease appeared only in developing countries, little research on it has been done. Research interest in the disease increased after an important epidemiological outbreak occurred in 2005 on the French metropolitan island of La Reunion located in the south-eastern part of the Indian Ocean. In 2007, a smaller outbreak of Chikungunya developed in the north-eastern part of Italy made possible by immigration of a viremic patient from the Indian Ocean area and the enormous population of Aedes albopictus in Italy. Currently, Chikungunya is spreading in Southeast Asian aspects, clinical pictures, diagnosis and treatment of the disease caused by Chikungunya virus.

Histological findings in foetuses congenitally infected by cytomegalovirus

BACKGROUND

Congenital cytomegalovirus (CMV) infection is a major cause of central nervous system damage leading to sensorineural hearing loss, mental retardation and cerebral palsy.

OBJECTIVES

Identify the type of organ involvement and understand the histopathogenesis of damage in foetuses of women with a CMV-highly positive amniotic fluid.

STUDY DESIGN

34 foetuses with congenital CMV infection documented by prenatal diagnosis were studied. Three foetuses died in utero. The remaining pregnancies were electively terminated at 20-21 weeks gestation.

RESULTS

Foetal organs positive for CMV antigens were: placenta (100%), pancreas (100%), lung (87%), kidney (87%), liver (71%), brain (55%) and heart (44%). Inflammatory infiltrate was almost always present in CMV-infected foetal organs and the severity of the inflammatory response was correlated with the organ damage. Brain damage with necrosis was observed in 33% (9/27) and a mild telencephalic leukoencephalopathy in 22% (6/27) of foetuses studied.

CONCLUSIONS

Focal necrosis was observed very frequently in organs such as pancreases, livers, hearts and kidneys. However the damage in these organs is likely to be resolved by parenchymal regeneration. Brain damage, which seems to be the results of a combined effect of viral infection, inflammatory infiltration and hypoxia due to severe placentitis, is less likely to be resolved because of the low regeneration ability of this organ.

Generalized Wegener's granulomatosis in an immunocompetent adult after cytomegalovirus mononucleosis and bacterial urinary tract infection

Human cytomegalovirus (HCMV) is frequently detected in autoimmune diseases, but its role in such disorders is poorly understood. Herein we describe the case of a young woman who developed generalized Wegener's granulomatosis (WG) after HCMV mononucleosis and urinary tract infection. During mononucleosis, the patient had extraordinarily high plasma levels of proinflammatory cytokines such as interleukin-5 and lymphotoxin alpha, autoantibodies, and a higher blood level of viral DNA than were found in other immunocompetent patients infected with HCMV or healthy controls. Active HCMV replication was detected after the onset of vasculitis, and HCMV genomes or antigens were found in blood, urine, and inflammatory lesions on the kidney. Thus, HCMV may have triggered or exacerbated inflammation and autoimmunity in this case of WG.

Diagnosis of bloodstream infections in immunocompromised patients by real-time PCR

OBJECTIVES

The diagnosis of bloodstream infections (BSIs) in immunocompromised patients, such as patients with cancer, is challenging. Although blood culture (BC) is considered the standard diagnostic tool for BSIs, it takes several days to yield results and has low sensitivity in these patients. Here, we tested a novel method for diagnosing BSIs in a large cohort of immunodepressed patients.

METHODS

Real-time PCR (LightCycler SeptiFast Test M(GRADE), Roche Diagnostics) was compared with BC for its ability to detect bacteria and fungi in blood samples from 100 immunocompromised patients (98 with cancer) in whom sepsis was suspected.

RESULTS

In concordant samples (79.2% of total cases), real-time PCR identified the presence or absence of microbes significantly faster than BC (p=3.7x10(-49), t-test). Furthermore, in 6 cases, SeptiFast distinguished contamination of BCs by coagulase-negative staphylococci. SeptiFast, however, failed to detect 5 cases of clinically relevant BSI that tested positive by BC.

CONCLUSIONS

SeptiFast rapidly diagnosed BSIs in our cohort of immunosuppressed patients. The results of this study suggest that SeptiFast can be used in conjunction with, but cannot replace, BC to better identify the etiology of fever in immunocompromised patients.

Human cytomegalovirus paralyzes macrophage motility through down-regulation of chemokine receptors, reorganization of the cytoskeleton, and release of macrophage migration inhibitory factor

Macrophages contribute to host defense and to the maintenance of immune homeostasis. Conversely, they are important targets of human cytomegalovirus (HCMV), a herpesvirus that has evolved many strategies to modulate the host immune response. Because an efficient macrophage trafficking is required for triggering an adequate immune response, we investigated the effects exerted by HCMV infection on macrophage migratory properties. By using endotheliotropic strains of HCMV, we obtained high rates of productively infected human monocyte-derived macrophages (MDM). Twenty-four hours after infection, MDM showed reduced polar morphology and became unable to migrate in response to inflammatory and lymphoid chemokines, bacterial products and growth factors, despite being viable and metabolically active. Although chemotactic receptors were only partially affected, HCMV induced a dramatic reorganization of the cytoskeleton characterized by rupture of the microtubular network, stiffness of the actin fibers, and collapse of the podosomes. Furthermore, supernatants harvested from infected MDM contained high amounts of macrophage migration inhibitory factor (MIF) and were capable to block the migration of neighboring uninfected MDM. Because immunodepletion of MIF from the conditioned medium completely restored MDM chemotaxis, we could show for the first time a functional role of MIF as an inhibitor of macrophage migration in the context of HCMV infection. Our findings reveal that HCMV uses different mechanisms to interfere with movement and positioning of macrophages, possibly leading to an impairment of antiviral responses and to an enhancement of the local inflammation.

HHV-6A in syncytial giant-cell hepatitis

Syncytial giant-cell hepatitis is a rare but severe form of hepatitis that is associated with autoimmune diseases, drug reactions, and viral infections. We used serologic, molecular, and immunohistochemical methods to search for an infectious cause in a case of syncytial giant-cell hepatitis that developed in a liver-transplant recipient who had latent infection with variant B of human herpesvirus 6 (HHV-6B) and who had received the organ from a donor with variant A latent infection (HHV-6A). At the onset of the disease, the detection of HHV-6A (but not HHV-6B) DNA in plasma, in affected liver tissue, and in single micromanipulated syncytial giant cells with the use of two different polymerase-chain-reaction (PCR) assays indicated the presence of active HHV-6A infection in the patient. Expression of the HHV-6A-specific early protein, p41/38, but not of the HHV-6B-specific late protein, p101, was demonstrated only in liver syncytial giant cells in the absence of other infectious pathogens. The same markers of HHV-6A active infection were documented in serial follow-up samples from the patient and disappeared only at the resolution of syncytial giant-cell hepatitis. Neither HHV-6B DNA nor late protein was identified in the same follow-up samples from the patient. Thus, HHV-6A may be a cause of syncytial giant-cell hepatitis.