Emergence of a VIM-1 MBL and CTX-M-15 ESbL-producing Klebsiella pneumoniae clone from acute and rehabilitation hospitals in Italy.

We report the emergence of VIM-1 MBL and CTX-M-15-producing K. pneumoniae isolates collected from patients at two acute care hospitals (I.R.C.C.S. "S. Matteo" and "Casa Sollievo della Sofferenza" Hospital) and a long-term rehabilitation facility in Northern Italy (I.R.C.C.S. "S. Maugeri"). Between February 2007 and October 2008, 30 K. pneumoniae strains showing decreased susceptibility to carbapenems were collected. PCR and sequencing experiments revealed the presence of blaVIM-1 gene in 14/30 isolates. All the above isolates carried the blaSHV-5 determinant as well; interestingly, 8/14 VIM positive isolates were also CTX-M-1- like producers. VIM-1 positive strains were present in all hospitals. PFGE genomic profiles of the 14/30 isolates showed that 2 different clones, A and B, were responsible for outbreaks. The coexistence in the same bacterial cell of compatible plasmids carrying epidemiologically important emerging resistance genes, such as MBLs and CTX-Ms, is worrisome since it could predict the generation and spread of pan-resistant bacteria and the consequent treatment option limitations that can lead to significant morbidity and mortality. Control measures should be applied to detect MBL-producing strains and to contrast the vertical and plasmidic diffusion of carbapenem-resistant K. pneumoniae in acute care and rehabilitation facilities.

Infection and coinfection of human rhinovirus C in stem cell transplant recipients.

In 54 adult stem cell transplant recipients, the presence and persistence of human rhinoviruses (including the novel lineage C) were evaluated by molecular detection and phylogenetic analysis, independently from respiratory symptoms. In the same group of patients, the presence of other coinfecting respiratory pathogens, including the novel enterovirus 109, was also evaluated.

The role of infections and coinfections with newly identified and emerging respiratory viruses in children.

Acute respiratory infections are a major cause of morbidity in children both in developed and developing countries. A wide range of respiratory viruses, including respiratory syncytial virus (RSV), influenza A and B viruses, parainfluenza viruses (PIVs), adenovirus, rhinovirus (HRV), have repeatedly been detected in acute lower respiratory tract infections (LRTI) in children in the past decades. However, in the last ten years thanks to progress in molecular technologies, newly discovered viruses have been identified including human Metapneumovirus (hMPV), coronaviruses NL63 (HcoV-NL63) and HKU1 (HcoV-HKU1), human Bocavirus (HBoV), new enterovirus (HEV), parechovirus (HpeV) and rhinovirus (HRV) strains, polyomaviruses WU (WUPyV) and KI (KIPyV) and the pandemic H1N1v influenza A virus. These discoveries have heavily modified previous knowledge on respiratory infections mainly highlighting that pediatric population is exposed to a variety of viruses with similar seasonal patterns. In this context establishing a causal link between a newly identified virus and the disease as well as an association between mixed infections and an increase in disease severity can be challenging. This review will present an overview of newly recognized as well as the main emerging respiratory viruses and seek to focus on the their contribution to infection and co-infection in LRTIs in childhood.

Epidemiological, molecular and clinical features of enterovirus 109 infection in children and in adult stem cell transplant recipients.

BACKGROUND: A novel human enterovirus (HEV) type within the species HEV-C, named EV109, was discovered from cases of respiratory illness in Nicaragua in September 2010. The aim of this study, was to retrospectively examine the presence and the role of EV109 in respiratory samples from two patients populations; infants below the age of 2 years, hospitalized for acute respiratory diseases (ARDs) and adult hematopoietic stem cell transplantation recipients. RESULTS: A total of 1149 nasopharingeal aspirates were collected and tested for the presence of EV109 by reverse transcription-PCR (RT-PCR). In positive samples, the presence of the most common respiratory viruses was also assayed and clinical symptoms were evaluated. Samples from 2 of the 974 infants tested positive for EV109 RNA (0.2%) and belonged to patients with lower ARDs; co-infection with other viral pathogens under study was observed in both cases. In transplant recipients, one out of the 175 samples analyzed, from a patients with upper respiratory simptoms tested positive for HEV 109 in the absence of co-infecting viruses. Sequence analysis of amplified EV109 genomic regions, showed only a few nucleotide differences when compared with the Nicaraguan strains. CONCLUSIONS: Overall these results indicate that HEV109 variants have circulated and differentiated in different lineages worldwide. Although more cases and larger studies are needed, HEV109 infection may be associated to ARDs both in infants and in hematopoietic stem cell transplantation recipients. If these preliminary observations will be confirmed, improved molecular methods with a wider panel of potential pathogens will be useful for monitoring these categories of patients.

Influence of lingual bracket position on microbial and periodontal parameters in vivo.

OBJECTIVE: Lingual orthodontics is becoming more popular in dental practice. The purpose of the present investigation was to compare plaque formation on teeth bonded with the same bracket onto buccal or lingual surface, with non-bonded control teeth, via an in vivo growth experiment over a 30-day period. MATERIAL AND METHODS: A randomized controlled trial with split-mouth design was set up enrolling 20 dental students. Within each subject sites with buccal and lingual brackets and control sites were followed. Clinical periodontal parameters (periodontal pocket depth: PPD; bleeding on probing: BOP) were recorded at baseline and on days 1, 7 and 30. Microbiological samples were taken from the brackets and the teeth on days 1, 7 and 30 to detect colony-forming units (CFU). Total CFU, streptococci CFU and anaerobe CFU were measured. RESULTS: No significant differences (P>0.05) were found between buccal and lingual brackets in terms of clinical periodontal parameters and microbiological values. CONCLUSION: Bracket position does not have significant impact on bacterial load and on periodontal parameters.

Influence of lingual bracket position on microbial and periodontal parameters in vivo

OBJECTIVE: Lingual orthodontics is becoming more popular in dental practice. The purpose of the present investigation was to compare plaque formation on teeth bonded with the same bracket onto buccal or lingual surface, with non-bonded control teeth, via an in vivo growth experiment over a 30-day period. MATERIAL AND METHODS: A randomized controlled trial with split-mouth design was set up enrolling 20 dental students. Within each subject sites with buccal and lingual brackets and control sites were followed. Clinical periodontal parameters (periodontal pocket depth: PPD; bleeding on probing: BOP) were recorded at baseline and on days 1, 7 and 30. Microbiological samples were taken from the brackets and the teeth on days 1, 7 and 30 to detect colony-forming units (CFU). Total CFU, streptococci CFU and anaerobe CFU were measured. RESULTS: No significant differences (P>0.05) were found between buccal and lingual brackets in terms of clinical periodontal parameters and microbiological values. Conclusion: Bracket position does not have significant impact on bacterial load and on periodontal parameters.

Differences in biofilm formation and aggregative adherence between beta-lactam susceptible and beta-lactamases producing P. mirabilis clinical isolates.

Biofilm formation of multidrug resistant (MDR) extended-spectrum beta-lactamase (ESbetaL) producing Proteus mirabilis isolates from a long-term care and rehabilitation facility (LTCRF) in Northern Italy was evaluated. A total of 10 strains, 4/10 producing the acquired AmpC beta-lactamase CMY-16, 3/10 producing the ESbetaL TEM-92 and the remaining negative for the presence of beta-lactamase genes, were studied using standard adherence assays on titer plates. Tests were performed in three different media, including Luria Bertani (LB), LB diluted and urine. Three representative strains were also tested for biofilm production in microtiter in presence of beta-lactam sub-MIC concentrations. The same isolates were screened for aggregative adherence onto monkey kidney cells (LLC-MK2). All strains studied were capable of biofilm formation, though at different levels. The beta-lactamase positive strains were statistically better significant in biofilm formation than negative ones regardless of growth medium. Cellular adherence assays showed a preferential ability of all isolates, regardless of beta-lactamase production, to adhere to inert surfaces rather than to cells. Although the results did not fully support a direct correlation between beta-lactamase production and biofilm formation, both mechanisms can greatly contribute to bacterial persistence in the urinary tract.

Molecular epidemiology of KI and WU polyomaviruses in infants with acute respiratory disease and in adult hematopoietic stem cell transplant recipients.

Polyomaviruses KI (KIPyV) and WU (WUPyV) were described recently in children with acute respiratory disease. The pathogenic potential of these human viruses has not been determined completely, but a correlation between immunosuppression and virus reactivation has been suggested. In the present study, the association between KI/WUPyV infection and immunosuppression was investigated using sequential nasopharyngeal aspirates from asymptomatic adult hematopoietic stem cell transplant recipients. In parallel, an investigation on the WU/KIPyV prevalence in children with acute respiratory disease was also carried out. Two of the 126 samples obtained from the 31 hematopoietic transplant recipients were positive for KIPyV (1 sample, 0.79%) and WUPyV (1 sample, 0.79%). Both samples were obtained 15 days after allogeneic transplantation and virus persistence was not observed in subsequent samples. In symptomatic children, 7 of the 486 nasopharyngeal aspirates were positive for WUPyV (1.4%) and 1 for KIPyV (0.2%). Single polyomavirus infection was detected in four patients, whereas the remaining patients were co-infected with respiratory syncityal virus (three patients) or adenovirus (one patient). The results suggest that WU/KIPyVs have a limited circulation in Italy and a low pathogenic potential in young children. Brief and asymptomatic infection can occur in hematopoietic transplant recipients.

Two-year prospective study of single infections and co-infections by respiratory syncytial virus and viruses identified recently in infants with acute respiratory disease.

A prospective 2-year analysis including 322 infant patients with acute respiratory disease (ARD) hospitalized in a pediatric department in northern Italy was carried out to evaluate the role as respiratory pathogens or co-pathogens of recently identified viruses. The presence of respiratory syncitial virus (RSV), human Metapneumoviruses (hMPVs), human Bocaviruses (hBoVs), and human Coronaviruses (hCoVs) was assayed by molecular detection and clinical symptoms evaluated. Nasopharyngeal aspirates from 150 of the 322 infants (46.6%) tested positive for at least one pathogen. Ninety samples (28.0%) tested positive for RSV RNA (61.5% genotype A and 38.5% genotype B), 46 (14.3%) for hMPV RNA (71.7% subtype A and 28.3% subtype B), 28 (8.7%) for hCoV RNA (39.3% hCoV-OC43, 35.7% hCoV-NL63, 21.4% hCoV-HKU1, and 3.6% hCoV-229E), and 7 (2.2%) for hBoV DNA (of the 6 typed, 50% subtype 1 and 50% subtype 2); 21/150 samples revealed the presence of 2 or more viruses. Co-infection rates were higher for hMPVs, hCoVs, and hBoV (38.3%, 46.4%, and 57.1%,) and lower for RSV (23.3%). RSV was associated with the presence of complications (P < 0.001) and hypoxia (P < 0.015). When the presence of RSV alone and the RSV-hMPV co-infections were considered, RSV mono-infected patients resulted to have longer hospitalization and higher hypoxia (P < 0.001). The data highlight that (i) RSV has a central role as a respiratory pathogen of infants, (ii) the wide circulation of recently identified viruses does not reduce the clinical and epidemiological importance of RSV, and that (iii) recently identified agents (hMPVs, hBoVs, and hCoVs) act as primary pathogens or co-pathogens.

Long-term study on symptomless human metapneumovirus infection in hematopoietic stem cell transplant recipients.

From October 2004 through October 2006 a study was performed to evaluate the prevalence of human Metapneumovirus (hMPV) infection in adult hematopoietic stem cell transplant (HSCT) recipients. Sequential nasopharyngeal aspirates (NPA) were collected independently from respiratory symptoms and evaluated for hMPV-RNA by polymerase chain reaction (PCR) and sequence analysis. Results indicate epidemiological and molecular differences between the 2004-2005 and 2005-2006 periods and that hMPV seems not to symptomatically affect HSCT patients or cause late respiratory sequelae. In addition, data collected suggest a hospital origin of hMPV infection in most HSCT patients during the 2004-2005 period.

Persistent symptomless human metapneumovirus infection in hematopoietic stem cell transplant recipients.

Sequential nasopharyngeal aspirates from patients without respiratory symptoms undergoing hematopoietic stem cell transplantation (HSCT) were tested for genomic RNA of human metapneumovirus (hMPV). Persistent hMPV infection was documented in most of them and confirmed by virus isolation. hMPV infection etiology was also evaluated during the same period in samples from pediatric patients with acute respiratory diseases (ARDs). Sequence analysis of hMPV in HSCT recipients documented infection by hMPV genotype A and strong interhost similarity; this pattern differs from that observed in pediatric patients with ARDs. The data indicate that HSCT recipients may frequently develop symptomless hMPV infection.