Evaluation of rapid KPC carbapenemase detection method based on MALDI-TOF VITEK MS spectra analysis.

Clinical microbiology laboratories in hospital settings need to be able to identify patients who carry carbapenemase-producing bacterial strains quickly in order to contain their spread and initiate proper pharmacological therapy. The aim of this study was to confirm the correlation between KPC production and a characteristic mass spectrometry (MS) peak (11 109 Da±8) to validate the use of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS as a rapid screening tool. With this aim, 176 selected clinical samples that were KPC-producing and 260 control samples that were carbapenem-susceptible or carbapenem-resistant through other resistance mechanisms, or were producing hydrolytic enzymes other than KPC, were analysed. The presence of the 11 109 Da peak in the spectra of 99.4 % (175/176) of the KPC-producing strains compared to the controls, which all lacked the peak, confirmed a strong correlation between KPC production and the presence of the 11 109 Da peak in the MALDI-TOF MS spectrum. The high sensitivity (98.7 %) and specificity (100 %) of the peak searching in the MALDI-TOF MS spectra mean that 11 109 Da peak searching is a suitable screening tool in KPC-endemic regions.

Coccidioidomycosis: first imported case in Italy.

We report a case of pulmonary coccidioidomycosis imported from the United States to Italy. This disease should enter in the differential diagnosis of any febrile patient (especially if presenting with pulmonary symptoms, with or without hypereosinophilia) coming from Coccidioides immitis endemic areas.

Unusual presentation of phosphoglycerate mutase deficiency due to two different mutations in PGAM-M gene.

Phosphoglycerate mutase (PGAM) deficiency causes a rare metabolic myopathy characterized by exercise-related myalgia and myoglobinuria. This disorder was described in 13 patients and five different mutations in the PGAM-M gene were identified. We report on a new patient with an unusual clinical presentation. As a youth, he participated in different sports without complaining of muscular symptoms, but at 44 years of age, after a brief, intense effort, he experienced lightheadedness without fainting. Serum CK was elevated and the ischemic exercise test showed a pathological lactate response. Muscle biopsy showed only mild abnormalities, but biochemical study revealed a defect of PGAM and genetic analysis showed two different mutations in the PGAM-M gene. Our case expands the clinical spectrum of PGAM deficiency and suggests that the frequency of this metabolic myopathy may be underestimated.

Novel mitochondrial tRNA Leu(CUN) transition and D4Z4 partial deletion in a patient with a facioscapulohumeral phenotype.

Point mutations in mtDNA-encoded tRNA genes frequently cause isolated myopathies but rarely cause the facioscapulohumeral phenotype. We report on a patient affected with chronic progressive weakness of facioscapulohumeral/peroneal muscles whose muscle biopsy showed a mitochondrial myopathy. mtDNA direct sequencing and RFLP analysis revealed a heteroplasmic transition T12313C which disrupts a conserved site in the T Psi C stem of the tRNA(Leu(CUN)) gene and fulfills the accepted criteria of pathogenicity. A partial deletion of the nuclear DNA D4Z4 region with residual repeat sizes of 25 kb was also found in the patient and in her mother. This is the first reported case of mitochondrial myopathy/facioscapulohumeral muscular dystrophy (FSHD) "double trouble".

Central-peripheral sensory axonopathy in a juvenile case of Alpers-Huttenlocher disease.

Peripheral ataxia is reported in a juvenile case of Alpers-Huttenlocher disease (AHD). Neurophysiological and neuropathological investigations revealed a central-peripheral axonopathy, affecting the deep sensation carried by the peripheral nerve fibres and the posterior tracts of the cord, due to neuronal loss of the sensory ganglia. Involvement of the sensory pathways is regarded as a major feature of juvenile AHD.

Features of cell death in brain and liver, the target tissues of progressive neuronal degeneration of childhood with liver disease (Alpers-Huttenlocher disease).

Alpers-Huttenlocher disease (AHD) is a rare encephalopathy of infancy and childhood characterized by myoclonic seizures and progressive neurological deterioration, usually associated with signs and symptoms of liver dysfunction. There is no biological marker of the disease, and ultimate diagnosis still relies on pathological examination. Features of clinical progression and pathological findings suggest AHD to be secondary to a genetically determined disorder of mitochondrial function. We report on four AHD patients and focus on their pathological features in brain, liver and muscle. Liver and muscle biopsy specimens were examined using histochemical markers of the oxidative pathways, probes to immunodetect molecules of the apoptotic cascades and electron microscopy. In liver (but not in muscle) biopsy samples, activated caspases were detected by immunohistochemistry: foci of caspase-9-positive cells were seen in a child affected with chronic, progressive fibrosis. In an 18-year-old boy, who suffered from valproic acid-associated acute hepatitis, caspase-3 cells were clustered among the necrotic foci and the foamy cells. In both patients electron microscopy revealed apoptotic nuclei. Normal muscle biopsy specimens were observed in two children, 2 and 8 years-old respectively; in the 18-year-old patient cytochrome oxidase-negative fibers as well as ultrastructural findings of mitochondrial abnormalities were observed. In no patient was there biochemical evidence of impaired oxidative metabolism. Neuropathological examination of the brains of two patients (13 months and 19 years old, respectively) showed focal distribution of the lesions affecting the telencephalic cortex and, to a lesser extent, subcortical gray nuclei. Along with the necrotizing lesions, characterized by neuronal loss, neuropil microcysts and newly formed vessels, we also observed acutely shrunken neurons and features of apoptotic cell death in the cerebral cortex only. Severe neuronal loss without necrotizing features was observed in the cerebellar cortex. The presence of both anoxic and apoptotic nuclei in brain and liver, the target tissues of the disease, is consistent with the hypothesis that abnormal activation of mitochondrion-related cell death pathways might be involved in the pathogenesis of AHD.