Cartesio Favalli

Modulation of natural killer activity by thymosin alpha 1 and interferon

SummaryA single injection of αβ-interferon (αβ-IFN) (30 000 units/mouse), a major biological modifier of natural killer (NK) cytolytic activity, strongly stimulated NK activity in normal mice, as expected, while the same treatment did not statistically alter the NK response in cyclophosphamide (CY)-suppressed animals.We investigated the possibility of thymosin α1 cooperating with αβ-IFN in boosting NK activity in CY-suppressed animals.The results show that treatment with thymosin α1 (200 μg/kg) for 4 days, followed by a single injection of αβ-IFN 24 h before testing, strongly restored NK activity in CY-suppressed mice. Thymosin α1 was, moreover, able to accelerate the recovery rate of NK activity in bone marrow reconstituted murine chimeras.Taken together the data support the concept that the synergic effect between thymosin α1 and αβ-IFN could be the result of effects on differentiation of the NK lineage at different levels.

Acinetobacter baumannii in intensive care unit: A novel system to study clonal relationship among the isolates

BackgroundThe nosocomial infections surveillance system must be strongly effective especially in highly critic areas, such as Intensive Care Units (ICU). These areas are frequently an epidemiological epicentre for transmission of multi-resistant pathogens, like Acinetobacter baumannii. As an epidemic outbreak occurs it is very important to confirm or exclude the genetic relationship among the isolates in a short time. There are several molecular typing systems used with this aim. The Repetitive sequence-based PCR (REP-PCR) has been recognized as an effective method and it was recently adapted to an automated format known as the DiversiLab system.MethodsIn the present study we have evaluated the combination of a newly introduced software package for the control of hospital infection (VIGI@ct) with the DiversiLab system. In order to evaluate the reliability of the DiversiLab its results were also compared with those obtained using f-AFLP.ResultsThe combination of VIGI@ct and DiversiLab enabled an earlier identification of an A. baumannii epidemic cluster, through the confirmation of the genetic relationship among the isolates. This cluster regards 56 multi-drug-resistant A. baumannii isolates from several specimens collected from 13 different patients admitted to the ICU in a ten month period. The A. baumannii isolates were clonally related being their similarity included between 97 and 100%. The results of the DiversiLab were confirmed by f-AFLP analysis.ConclusionThe early identification of the outbreak has led to the prompt application of operative procedures and precautions to avoid the spread of pathogen. To date, 6 months after the last A. baumannii isolate, no other related case has been identified.

Antiviral activity of a synthetic analog of prostaglandin A in mice infected with influenza A virus

SummaryWe have previously shown that prostaglandins of the A series potently inhibit virus replication in several virus-host systems in vitro. In the present report we have studied the effect of a long-acting synthetic analog of PGA, 16,16-dimethyl-PGA2 (Di-M-PGA2), on virus infection in vivo, using as a model Balb/c mice infected with influenza A (PR8) virus. Depending upon the dose of viral inoculum, PR8 virus caused the death of 50 to 100% of the animals in a period of 8–20 days. Di-M-PGA2-treatment significantly increased mouse survival by an average of 40%, independently of the dose of inoculum and the age of the animals. The fact that Di-M-PGA2-treatment decreased virus titers in the lungs and did not alter the host immune response, suggested that PGAs therapeutic action was due to suppression of virus replication. Finally, two anti-inflammatory compounds, which inhibit prostaglandin synthesis, aspirin and indomethacin, were shown not to significantly alter mouse survival in this system.

Emergence of KPC-producing Klebsiella pneumoniae in Italy

BackgroundThe emergence of KPC-producing K. pneumoniae has now become a global concern. KPC beta-lactamases are plasmid-borne and, like extended spectrum beta lactamases (ESBLs), can accumulate and transfer resistance determinants to other classes of antibiotics. Therefore, infection control guidelines on early identification and control of the spread of organisms carrying these resistant determinants are needed.FindingsKlebsiella pneumoniae carbapenemase (KPC) was detected in two isolates of carbapenem-resistant K. pneumoniae obtained from patients at an Italian teaching hospital. The first strain was isolated from a culture drawn from a central venous device (CVC) in a patient with Crohns disease who was admitted to a gastroenterology ward. The second was isolated from a urine sample collected from an indwelling urinary catheter in an intensive care unit (ICU) patient with a subdural haematoma. The patients had not travelled abroad. Both isolates were resistant to all β-lactams and were susceptible to imipenem and meropenem but resistant to ertapenem. Isolates also showed resistance to other classes of non-β-lactam antibiotics, such as quinolones, aminoglycosides (with the exception for amikacin), trimethoprim-sulfamethoxazole (TMP-SMX) and nitrofurantoin. They were determined to contain the plasmid encoding the carbapenemase gene bla-KPC and were also positive in the Hodge test.ConclusionsThis is the second report of KPC-producing isolates in Italy, but the first concerning KPC type 2 gene, and it may have important implications for controlling the transmission of microorganisms resistant to antibiotics.

A synthetic analog of prostaglandin E2 is able to induce in vivo theta antigen on spleen cells of adult thymectomized mice

Abstract The effect of prostaglandins on the in vivo induction of theta antigen in splenic spontaneous rosette-forming cells derived from adult thymectomized mice was studied. A long-acting synthetic analog of prostaglandin E 2 , di-M-PGE 2 , mimicked the effects of thymic hormone and was active when mice were treated with as little as 0.1 μg ip. In addition, indomethacin, a potent inhibitor of prostaglandin biosynthesis, was able to reverse the inductive effects of exogenous thymic hormone and inhibit the expression of theta antigen in normal mice, presumably by interfering with the effect of endogenous thymic factors. Finally, indomethacin also partially suppressed the stimulatory effects of exogenously administered di-M-PGE 2 , suggesting that this agent is effective, at least in part, because it stimulates endogenous prostaglandin biosynthesis. Possible mechanisms of action for the effects of prostaglandins are presented.

Modulation of endogenous prostaglandins by thymosin-α1 in lymphocytes

Abstract The effects of thymosin- α 1 on the stimulation of specific release of prostaglandin E 2 (PGE 2 ) from splenic lymphocytes and thymocytes were studied. Experiments were also performed to study in parallel the absolute levels of thymosin- α 1 in the blood and the induction of serum FTS activity and of azathioprine sensitivity of spleen cells from adult thymectomized (ATx) mice. A significant difference in the release of PGE 2 between normal splenocytes and splenocytes from ATx mice was observed. Thymosin- α 1 at certain concentrations was able to stimulate PGE 2 release from lymphocytes of ATx mice while inhibiting release in lymphocytes of normal mice. Also, thymocytes were stimulated to release PGE 2 after incubation with α 1 in a manner similar to that seen in spleen cells of ATx mice. Approximately the same concentration of α 1 was found to also correct the low azathioprine sensitivity of splenocytes from ATx mice. Determinations of FTS-like activity in the blood and the pharmacokinetics of α 1 after administration of this synthetic molecule show a clear dissociation. A maximum peak of α 1 activity was obtained after 1 hr, while maximal FTS-like activity was observed after 24 hr. The inhibition of the induction by α 1 of FTS-like activity and of Thy 1.2 antigen by indomethacin suggests that the action of α 1 requires prostaglandin biosynthesis.

Induction of serum thymic-like activity in adult thymectomized mice by a synthetic analog of PGE2.

Abstract The administration of di-M-PGE 2 , a synthetic analog of PGE 2 , restores a serum thymic-like activity in adult thymectomized mice. This effect is completely abolished by indomethacin administration. Furthermore, indomethacin administration also abrogates the restoring action of thymosin Fraction 5 on serum thymic-like activity, and lowers the natural serum thymic-like activity present in normal mice. It is suggested that prostaglandins mediate some effects induced by thymic hormones.

A Multi-Target Real-Time PCR Assay for Rapid Identification of Meningitis-Associated Microorganisms

A central nervous system (CNS) infection, such as meningitis, is a serious and life-threatening condition. Bacterial meningitis can be severe and may result in brain damage, disability or even death. Rapid diagnosis of CNS infections and identification of the pathogenic microorganisms are needed to improve the patient outcome. Bacterial culture of a patient’s cerebrospinal fluid (CSF) is currently considered the “gold standard” for diagnosing bacterial meningitis. From the CSF cultures researchers can assess the in vitro susceptibility of the causative microorganism to determine the best antibiotic treatment. However, many of the culture assays, such as microscopy and the latex agglutination test are not sensitive. To enhance pathogen detection in CSF samples we developed a multi-target real-time PCR assay that can rapidly identify six different microorganisms: Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Streptococcus agalactiae, Listeria monocytogenes and Cryptococcus neoformans. In this study we applied this PCR analysis to 296 CSF samples from patients who were suspected of having meningitis. Of the 296 samples that were examined, 59 samples were positive according to the CSF culture and/or molecular assays. Forty-six CSF samples were positive for both the CSF culture and our real-time PCR assay, while 13 samples were positive for the real-time PCR but negative for the traditional assays. This discrepancy may have been caused by the fact that these samples were collected from 23 patients who were treated with antimicrobials before CSF sampling.

Comparison of the eSwab collection and transportation system to an amies gel transystem for Gram stain of clinical specimens

BackgroundThe first step in routine microbiology laboratory procedures is the collection and safe transportation of swab samples. This can be accomplished using ESwab Collection and Transport System (Copan Italia, Brescia -Italy). The aim of the present study was to compare the results of microscopic examination of gram stain smears prepared directly from clinical specimens, collected and transported in the ESwab, with those obtained using Amies Agar gel Transystem without charcoal (Copan).FindingsSpecimens were collected from 80 patients (32 vaginal swabs, 27 cervical swabs, 11 urethral swabs and 10 wound swabs). Two swabs were in random order collected from each patient, one using the conventional Amies gel Transystem, the other using ESwab. One slide was prepared for each specimen using the conventional swab and two sets of slides were prepared from the specimens collected with the ESwab: one using 100 μl and one using 50 μl of the Amies medium. All slides were gram stained using an automated Gram stainer. Microscopic examination of 240 slides (80 with conventional and 160 with ESwab) showed that the quality of smear preparation from the ESwab system, allowed for easier identification of human cells and identification of greater number of microorganisms. Microscopic examination of additional slides prepared from ESwab at 24 or 72 hours after initial collection were equivalent to those prepared when received in the laboratory within 2 hours of collection.ConclusionMicroscopic examination performed using ESwab, especially when preparing the slides with 100 μl, shows superior results to those obtained using the Amies gel Transystem.

Effect of in vivo administration of prostaglandins and interferon on natural killer activity and on B-16 melanoma growth in mice

We investigated the effect on in vivo administration of 16,16-dimethyl-prostaglandin E2 (di-M-PGE2) alone and in combined treatment with alpha-beta interferon (IFN) on NK activity in normal, cyclophosphamide (CY)-treated, tumor bearing or irradiated and bone marrow reconstituted mice and on B-16 melanoma growth. Normal mice inoculated with IFN (30,000 U/mouse, 24 hr before testing) showed a significant increase in NK activity, while those treated with di-M-PGE2 (10 micrograms/mouse daily X 4 days) showed a suppressed NK response. No difference was observed between mice treated with di-M-PGE2 alone and those treated with di-M-PGE2 associated with IFN. In immunosuppressed animals single treatments were slightly (di-M-PGE2) or not (IFN) effective, while the combined administration of di-M-PGE2 and IFN caused a marked increase in NK activity. Moreover, di-M-PGE2 was able to accelerate the recovery rate of NK activity in bone marrow-reconstituted murine chimeras, suggesting that the synergistic effect of prostaglandins and IFN could derive from the action of di-M-PGE2 on progenitor pre-NK cells and of IFN on effector cells. Finally, we observed a good correlation between the enhancement of the NK activity and the tumor growth inhibition.