Serratia marcescens in a neonatal intensive care unit: two long-term multiclone outbreaks in a 10-year observational study.

We investigated two consecutive Serratia marcescens (S. marcescens) outbreaks which occurred in a neonatal intensive care unit (NICU) of a tertiary level hospital in North Italy in a period of 10 years (January 2003-December 2012). Risk factors associated with S. marcescens acquisition were evaluated by a retrospective case-control study. A total of 21,011 clinical samples was examined: S. marcescens occurred in 127 neonates: 43 developed infection and 3 died. Seven clusters were recorded due to 12 unrelated clones which persisted for years in the ward, although no environmental source was found. The main epidemic clone A sustaining the first cluster in 2003 reappeared in 2010 as an extended spectrum ?-lactamase (ESBL)-producing strain and supporting the second epidemic. Birth weight, gestational age, use of invasive devices and length of stay in the ward were significantly related to S. marcescens acquisition. The opening of a new ward for non-intensive care-requiring neonates, strict adherence to alcoholic hand disinfection, the timely identification and isolation of infected and colonized neonates assisted in containing the epidemics. Genotyping was effective in tracing the evolution and dynamics of the clones demonstrating their long-term persistence in the ward.

The encapsulated strain TIGR4 of Streptococcus pneumoniae is phagocytosed but is resistant to intracellular killing by mouse microglia.

The polysaccharide capsule is a major virulence factor of Streptococcus pneumoniae as it confers resistance to phagocytosis. The encapsulated serotype 4 TIGR4 strain was shown to be efficiently phagocytosed by the mouse microglial cell line BV2, whereas the type 3 HB565 strain resisted phagocytosis. Comparing survival after uptake of TIGR4 or its unencapsulated derivative FP23 in gentamicin protection and phagolysosome maturation assays, it was shown that TIGR4 was protected from intracellular killing. Pneumococcal capsular genes were up-regulated in intracellular TIGR4 bacteria recovered from microglial cells. Actual presence of bacteria inside BV2 cells was confirmed by transmission electron microscopy (TEM) for both TIGR4 and FP23 strains, but typical phagosomes/phagolysosomes were detected only in cells infected with the unencapsulated strain. In a mouse model of meningitis based on intracranic inoculation of pneumococci, TIGR4 caused lethal meningitis with an LD(50) of 2 × 10² CFU, whereas the LD(50) for the unencapsulated FP23 was greater than 107 CFU. Phagocytosis of TIGR4 by microglia was also demonstrated by TEM and immunohistochemistry on brain samples from infected mice. The results indicate that encapsulation does not protect the TIGR4 strain from phagocytosis by microglia, while it affords resistance to intracellular killing.

Commercial DNA probes for mycobacteria incorrectly identify a number of less frequently encountered species.

Although commercially available DNA probes for identification of mycobacteria have been investigated with large numbers of strains, nothing is known about the ability of these probes to identify less frequently encountered species. We analyzed, with INNO LiPA MYCOBACTERIA (Innogenetics) and with GenoType Mycobacterium (Hein), 317 strains, belonging to 136 species, 61 of which had never been assayed before. INNO LiPA misidentified 20 taxa, the majority of which cross-reacted with the probes specific for Mycobacterium fortuitum and the Mycobacterium avium-Mycobacterium intracellulare-Mycobacterium scrofulaceum group. GenoType misidentified 28 taxa, most of which cross-reacted with M. intracellulare and M. fortuitum probes; furthermore, eight species were not recognized as members of the genus Mycobacterium. Among 54 strains investigated with AccuProbe (Gen-Probe), cross-reactions were detected for nine species, with the probes aiming at the M. avium complex being most involved in cross-reactions.

Effect of eucalyptus essential oil on respiratory bacteria and viruses.

The activity of Eucalyptus globulus essential oil was determined for 120 isolates of Streptococcus pyogenes, 20 isolates of S. pneumoniae, 40 isolates of S. agalactiae, 20 isolates of Staphylococcus aureus, 40 isolates of Haemophilus influenzae, 30 isolates of H. parainfluenzae, 10 isolates of Klebsiella pneumoniae, 10 isolates of Stenotrophomonas maltophilia and two viruses, a strain of adenovirus and a strain of mumps virus, all obtained from clinical specimens of patients with respiratory tract infections. The cytotoxicity was evaluated on VERO cells by the MTT test. The antibacterial activity was evaluated by the Kirby Bauer paper method, minimum inhibitory concentration, and minimum bactericidal concentration. H. influenzae, parainfluenzae, and S. maltophilia were the most susceptible, followed by S. pneumoniae. The antiviral activity, assessed by means of virus yield experiments titered by the end-point dilution method for adenovirus, and by plaque reduction assay for mumps virus, disclosed only a mild activity on mumps virus.

Unusual concurrent detection by polymerase chain reaction of Bartonella henselae and parvovirus b19 in an immunocompetent child with erythema nodosum and hepatic granulomatous disease.

We report an unusual case of documented Bartonella henselae genotype I from hepatic tissue in an Italian immunocompetent girl presenting with erythema nodosum and hepatic granulomata. Polymerase chain reaction (PCR) was performed on biopsied liver sample to confirm the etiologic role of B. henselae and to identify the genetic variant of this organism. A PCR on the same liver biopsy for parvovirus B19 was also positive, but the clinical meaning of this was not clear.

A rare case of localized mucosal leishmaniasis due to Leishmania infantum in an immunocompetent Italian host.

The case of authoctonous isolated laryngeal leishmaniasis due to L. infantum in an italian immunocompetent host is reported. It is highlighed the need to consider mucosal leishmaniasis in the differential diagnosis of laryngeal tumors. Rapid nested-PCR technique and enzyme restriction analysis were useful for diagnosis and species identification directly from bioptic samples.

Interaction between saquinavir and antimycotic drugs on C. albicans and C. neoformans strains.

Candidiasis and cryptococcosis are the most common fungal diseases among patients suffering from HIV infection. In the present work we assess whether the combined therapies, proteinase inhibitors and antimycotic drugs, could modify the therapeutic effect of antimycotics. An in vitro study to evaluate the antifungal effect of saquinavir and antimycotic drugs combination on yeast growth was performed. Strains of C. albicans and C. neoformans from HIV-seropositive patients were used. Susceptibility tests of yeasts to amphotericin B, 5-fluorocytosine, miconazole and fluconazole, singly and in combination with saquinavir, were performed in two different media. In the combinations the antimycotic agents and saquinavir were tested at sub-inhibitory concentrations: 0.1-10 microg ml(-1) and 12.50 microg ml(-1), respectively. The fractionary inhibitory concentration (FIC) index was also calculated. The results show that the interaction between saquinavir and all the antimycotic drugs never resulted in antagonism. Fluconazole acts in more synergistic way, no matter which medium is used. The combined therapy miconazole/saquinavir results in synergism, especially in Sabouraud. The total absence of antagonism and the presence of synergism suggest that a combined therapy could be proposed in the treatment of HIV-seropositive patients to reduce side effects, thanks to the use of lower doses of antimycotic drugs.