Molecular Surveillance and Population Structure Analysis of Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus in High-Risk Wards

In this study we report the results of analysis of 253 isolates of Staphylococcus aureus (132 methicillin [meticillin]-resistant S. aureus [MRSA] isolates and 121 methicillin-susceptible S. aureus [MSSA] isolates) from 209 patients admitted to 18 high-risk wards of six hospitals located in Florence, Italy, over an 8-month period during which a program of epidemiological surveillance of hospital-acquired infections was conducted. The majority (69%) of the 87 reported S. aureus infections were caused by MRSA. No outbreak events have been reported. All the isolates were typed by amplified fragment length polymorphism (AFLP), and AFLP profiles were analyzed in order to define similarity groups. The discriminatory power of AFLP is very high with MSSA (Simpson index of diversity [D], 95.9%), whereas its resolution capability with MRSA (D, 44.7%) is hampered by the well-known high clonality of these populations (the main MRSA group accounted for 74% of the MRSA isolates). Combining AFLP, improved by visual inspection of polymorphisms, with multiplex PCR greatly increases MRSA resolution (D, 85.5%), resolving the MRSA population to a level that is one of the highest reported in the literature. Widespread and sporadic clones of MSSA and MRSA were identified, and their diffusion in the different hospitals and wards over the surveillance period was studied. The understanding of MSSA and MRSA population structures should be the starting point for the design of a more rational surveillance program for S. aureus species, maximizing benefits and reducing the cost of infection control strategies.Surveillance of hospital-acquired infections (HAIs), as a critical part of any infection control program, is an indispensable instrument for identification of the dimensions of the problem, for early recognition of changes in infection patterns, and for monitoring of infection trends and rates. Furthermore, surveillance programs allow one to evaluate the effectiveness of interventions, reinforcing good practices and influencing key hospital staff and decision makers (3, 16).Molecular typing techniques greatly improve the quality of epidemiological information obtained by surveillance programs, allowing more-accurate differentiation of strains. Molecular typing techniques are very useful for recognizing sporadic, unrelated strains and endemic, persistent strains (1, 30) and for determining if a single strain or different unrelated strains are the cause of observed increases in the frequency of HAIs by a microbial species.Staphylococcus aureus is one of the main etiologic agents of HAIs, particularly in high-risk wards such as intensive care units (ICUs), and methicillin (meticillin)-resistant S. aureus (MRSA) strains are more frequently involved than methicillin-susceptible S. aureus (MSSA) strains (12, 35). This situation turns out to be particularly serious due to the diffusion of highly pathogenic and multidrug-resistant strains (6).The low degree of genetic variability reported for MRSA populations (30) is a major limitation to strain identification, especially when a short time period and a limited area, such as a single hospital, are monitored. Different molecular typing techniques have been used to point out minor but epidemiologically significant genetic differences between MRSA strains (7, 23, 32, 33, 34). No single technique is clearly superior to others in the resolution of MRSA populations, and a combination of two or more methods has been suggested to be the most efficacious approach (23, 34).Unlike MRSA strains, which have been the subject of several studies of virulence, pathogenesis, development of new antibiotic resistances, strain diffusion worldwide and in hospital settings, and genome analysis (5, 11, 14, 21, 28), MSSA strains, because of their susceptibility to first-line antibiotics, have only occasionally been the subject of molecular epidemiological studies in hospital settings (7, 38). Recent studies performed by multilocus sequence typing have shown a strong genetic relationship between MRSA and MSSA strains, suggesting that MRSA clones arise on multiple occasions from successful hospital MSSA clones by horizontal acquisition of the methicillin resistance (mec) gene (8).In this work, we report the results obtained from an extended molecular surveillance program for S. aureus carried out for 18 high-risk wards of six hospitals in Florence, Italy, over an 8-month period. Our aim was to study the population structure and the diffusion of the MRSA and MSSA strains that colonize and infect patients admitted to the wards under observation. With this aim, amplified fragment length polymorphism (AFLP) analysis was utilized to type MRSA and MSSA isolates, whereas multiplex PCR was used to subtype MRSA isolates falling into the same AFLP group. The Simpson index was employed to evaluate the discriminatory powers of the two molecular techniques and to analyze the structures of both the MRSA and the MSSA populations.     

Totally endoscopic subxiphoid pericardioscopy: early steps with a new surgical tool

Background  Pericardial pathology still has challenging diagnostic and treating issues. To reduce surgical trauma and pain for the patient, the authors developed a totally endoscopic echo-guided approach for both diagnostic and operative pericardioscopy. Methods  Three steps moved from animal model (8 pigs) through concomitant open-chest interventions (7 patients) to closed-chest interventions for 10 patients with a diagnosis of severe pericardial effusion. Results  A lesion of the right ventricle in one patient (10%) due to imperfect preoperative pericardial visualization needed sternotomy for repair. All the patients, except the aforementioned one, underwent surgery with local anesthesia or mild sedation. No method-related mortality was reported. Conclusion  The closed-chest nonintrapleural approach to the pericardium may represent an evolution, with a positive impact on the treatment of this pathology. Therapeutic maneuvers with rigid instruments in nonintubated patients are possible. Accurate patient selection and technical refinement should increase the safety and effectiveness of the method.     

Malignant progression in pleomorphic xanthoastrocytoma: personal experience and review of the literature

Pleomorphic xanthoastrocytoma (PXA) is a rare primary low-grade astrocytic tumor, recently classified as a neuroglial tumor. It generally occurs in children and young adults and shows benign behaviour (WHO II), although an anaplastic variant and malignant potential have been described. Pleomorphic xanthoastrocytomas with malignant transformation have been reported in three out of eight patients operated on for this type of tumor in our department in the last 15 years. The three patients were two adult women and a child, the primary tumors were located in the cortex of the right temporal lobe, and treatment consisted of complete surgical resection. Histological examination revealed simple PXA in two patients and a PXA with anaplastic foci in the other. Mean recurrence time was 5.7 years, with the original xanthoastrocytoma evolving to glioblastoma in two cases and anaplastic astrocytoma in the third. All three patients underwent a second operation, followed by adjuvant therapies. Two died from tumor progression and one from brain edema after intracerebral haemorrhage. A review of the available PXA literature dating back to 1979 revealed 16 cases of primary anaplastic astrocytoma and 21 cases of PXA with malignant transformation. Our experience adds three more cases of malignant transformations, outlining once again the potential malignancy of pleomorphic xanthoastrocytomas and the fact that prognosis in these cases is the same as for primary anaplastic astrocytoma and glioblastoma. Analysis of glioneuronal markers, Ki67 and p53 in all pleomorphic xanthoastrocytomas did not prove to be a discriminating factor to identify a subgroup of xanthoastrocytomas prone to malignancy. Accordingly, these tumors demand close long-term clinical and radiological follow-up.     

Predictors of quality of life among patients with multiple sclerosis: an Italian cross-sectional study

The Functional Assessment of Multiple Sclerosis (FAMS) quality of life (QoL) instrument is a disease-specific, self-report questionnaire that was developed originally for US English-speaking patients. Here, the psychometric properties of the FAMS QoL questionnaire for Italian-speaking patients with multiple sclerosis (MS) are evaluated and compared with the results from the original FAMS validation survey (n=377). Eighteen Italian centers and 344 patients with MS participated in the study. The overall reliability (as expressed by Cronbach's alpha value) of the FAMS score, and its subscale scores, was always over the threshold of 0.8. Patients with benign MS showed a better overall QoL compared with patients with relapsing-remitting MS (RRMS; p=0.017), whereas patients with RRMS had a better QoL than patients with primary progressive MS (PPMS). No difference in QoL was found between patients with PPMS and those with secondary progressive MS. The Italian FAMS questionnaire is a valid measure to assess the QoL concerns of patients with MS. FAMS is also easy to administer and is well accepted by patients.     

Specific tumor suppressor function for E2F2 in Myc-induced T cell lymphomagenesis

Deregulation of the Myc pathway and deregulation of the Rb pathway are two of the most common abnormalities in human malignancies. Recent in vitro experiments suggest a complex cross-regulatory relationship between Myc and Rb that is mediated through the control of E2F. To evaluate the functional connection between Myc and E2Fs in vivo, we used a bitransgenic mouse model of Myc-induced T cell lymphomagenesis and analyzed tumor progression in mice deficient for E2f1, E2f2, or E2f3. Whereas the targeted inactivation of E2f1 or E2f3 had no significant effect on tumor progression, loss of E2f2 accelerated lymphomagenesis. Interestingly, loss of a single copy of E2f2 also accelerated tumorigenesis, albeit to a lesser extent, suggesting a haploinsufficient function for this locus. The combined ablation of E2f1 or E2f3, along with E2f2, did not further accelerate tumorigenesis. Myc-overexpressing T cells were more resistant to apoptosis in the absence of E2f2, and the reintroduction of E2F2 into these tumor cells resulted in an increase of apoptosis and inhibition of tumorigenesis. These results identify the E2f2 locus as a tumor suppressor through its ability to modulate apoptosis.     

Anomalous intrathoracic left vagus and recurrent laryngeal nerve course

An anomalous course of the vagus nerve is an extremely rare congenital anomaly. We report the case of a 59-year-old man who had left lung cancer. We performed a left upper lobectomy and mediastinal lymphadenectomy, paying attention to the pathway of the left vagus nerve, which had an anomalous course passing anteriorly to the left pulmonary trunk between the apical and anterior branches. The left recurrent laryngeal nerve hooked around the lower border of the apical branch of the left pulmonary artery.     

N-Ratio: a Novel Independent Prognostic Factor for Patients with Stage-III Cutaneous Melanoma

Background In this study, we tested the hypothesis that the ratio between metastatic and excised lymph nodes (“N-ratio”) might have an independent prognostic value in patients with TNM stage-III cutaneous melanoma. Methods The clinical records of 213 melanoma patients who had undergone radical lymph node dissection (RLND) and were found to harbor pathology-proven metastatic disease were used for analysis. The following clinico-pathological variables were considered for the prognostic study: patient’s age and sex, primary tumor site, tumor thickness, Clark’s level, ulceration, absolute number of positive lymph nodes, total number of excised lymph nodes, TNM stage (IIIA, IIIB, IIIC), and N-ratio (N-ratio A, ≤10%; N-ratio B, 10–25%; N-ratio C, >25%). Results Patients were categorized into three N-ratio classes according to the percentage of metastatic lymph nodes (N-ratio A, n = 94; N-ratio B, n = 95; N-ratio C, n = 24). The mean follow-up was 40 months. At univariate survival analysis, tumor thickness (P < 0.0001), ulceration (P = 0.046), Clark’s level (P = 0.0002), number of positive lymph nodes (P < 0.0001), TNM stage (P < 0.0001), and N-ratio (P < 0.0001) were significantly associated with overall survival (OS). Interestingly, the Cox proportional hazard model showed that, along with tumor thickness (HR 1.069, P = 0.008) and TNM stage (HR 1.696, P = 0.015), N-ratio (HR 1.578, P = 0.012) also independently predicted OS. Conclusions N-ratio is a novel easy-to-obtain independent prognostic factor for melanoma patients with lymph node metastases and might provide clinicians with additional information suitable for patient stratification while choosing adjuvant treatment. Validation of these results in larger prospective series is warranted to implement N-ratio in the routine clinical setting.     

6-Hydroxydopamine lesion in the ventral tegmental area fails to reduce extracellular dopamine in the cerebral cortex

Dopamine and noradrenaline are both involved in modulation of superior cognitive functions that are mainly dependent on frontal cortex activity. Experimental evidence points to parallel variations in extracellular concentrations of catecholamines in the cerebral cortex, which leads us to hypothesize their corelease from noradrenergic neurons. This study aimed to verify this hypothesis, by means of cerebral microdialysis following destruction of dopaminergic innervation in rats. The unilateral injury of dopaminergic neurons, by 6-hydroxydopamine injection in the ventral tegmental area, dramatically reduced the immunoreactivity for dopamine transporter in the cerebral hemisphere ipsilateral to the lesion. Tissue dopamine content in the ipsilateral nucleus accumbens and medial prefrontal and parietal cortex was also profoundly decreased, whereas noradrenaline was only slightly affected. Despite the lower tissue content in the denervated side, the extracellular dopamine level was not changed in the cortex, although it was markedly decreased in the nucleus accumbens ipsilateral to the lesion. The effect of drugs selective for D(2)-dopaminergic (haloperidol) or alpha(2)-noradrenergic (RS 79948) receptors was verified. Haloperidol failed to modify extracellular dopamine in either cortex but increased it in the nucleus accumbens, such an increase being greatly reduced in the denervated side. On the other hand, RS 79948 increased extracellular dopamine and DOPAC in all areas tested, the increases being of the same degree in both intact and lesioned sides. The results strongly support the hypothesis that the majority of extracellular dopamine in the cortex, unlike that in the nucleus accumbens, originates from noradrenergic terminals.     

Is there a "neural efficiency" in athletes? A high-resolution EEG study

“Neural efficiency” hypothesis posits that cortical activity is spatially focused in experts. Here we tested the hypothesis that compared to non-athletes, elite athletes are characterized by a reduced cortical activation during visuo-motor tasks related to the field of expertise, as a function of movement side. EEG data (56 channels; EB-Neuro) were continuously recorded in the following right-handed subjects: 11 non-athletes, 11 elite fencing athletes, and 11 elite karate athletes. During the EEG recordings, they observed pictures with fencing and karate attacks, and had to quickly click a right (left) keyboard button for the attacks at right (left) monitor side. The EEG data were averaged with respect to the movement onset, and were spatially enhanced by surface Laplacian estimation. The potentials related to the preparation (readiness potential) and initiation (motor potential) of the movements were measured. For the right movement, the potentials overlying supplementary motor and contralateral sensorimotor areas were higher in amplitude in the non-athletes than in the elite karate and fencing athletes. Furthermore, the amplitude of the motor potential over ipsilateral sensorimotor area was higher in the elite karate than fencing athletes, and its distribution over bilateral sensorimotor areas was less asymmetrical in the karate than in the other two groups. For the left movement, these potentials showed no difference between the groups. The present results suggest that “neural efficiency” hypothesis does not fully account for the organization of motor systems in elite athletes. “Neural efficiency” would depend on several factors including side of the movement, hemisphere, and kind of athletes.