Incidence and molecular epidemiology of Pseudomonas aeruginosa bacteremias in patients with acute leukemia: analysis by pulsed-field gel electrophoresis.

The incidence and molecular epidemiology of P. aeruginosa bacteremias, were monitored in patients with acute leukemia to define mechanisms of possible nosocomial transmission. From September 1997 to March 2001 febrile episodes were examined and blood isolates of P. aeruginosa were studied employing Pulsed-Field gel Electrophoresis (PFGE). Evaluation of DNA correlation was performed according to Tenover criteria. A total of 309 febrile episodes occurred in 187 patients. Of 139 organisms isolated in 116 bacteremias, 48% were gram negative bacilli (GNB); P. aeruginosa bacteremias were recorded in 34 (51%) of GNB sepsis. Evaluation of DNA correlation showed 2 related in 1997, 7 related in 1998, 10 related in 1999, 6 related in 2000-2001 (mainly closely and possibly related); therefore isolates closely related among themselves were also possibly related with other strains. About 60% of patients with related strains were hospitalized in the same room or in different rooms but became infected in the same period. Our data suggest a horizontal spread among the patients even if other sources were possible. The study assessed the usefulness of PFGE in bacteriological epidemiology.

Antibiotic prophylaxis in clean neurosurgery.

Two regimens of antibiotic prophylaxis are in use at our institution. These protocols consist in perioperative administration of a single dose of amoxicillin-clavulanic acid of 2.2 g at induction and 8 h later and irrigation of the surgical wound with rifamycin before closure. In cases of dirty surgery, placement of external shunts or foreign bodies, we administer vancomycin 1.5 g/die and ceftazidime 6 g/die for 72 h. A retrospective study of all the clean operations we performed in the last 2 years yielded a total of 793 consecutive procedures with three postoperative wound infections. These results are in agreement with the majority of series reported in literature, although different prophylactic protocols are applied and in some cases no prophylactic antibiotics are administered at all. The use of these agents in clean neurosurgery remains, as a matter of fact, controversial. In order to further investigate this issue we took three or more intraoperative samples for culture in 40 clean cases. Only in 2% of these samples were cultures positive. Although lacking statistical significance, these results are interesting indications of the appropriateness of antimicrobial prophylaxis in clean neurosurgery and invite further investigation in that direction.

[Frequency and antibiotic susceptibility of urinary pathogens isolated in the microbiology and virology laboratory of the Careggi General Hospital in the period July-December 1996]. / Frequenza e sensibilità agli antibiotici di patogeni urinari isolati nel laboratorio di microbiologia e virologia dell'Azienda Ospedaliera di Careggi nel periodo luglio-dicembre 1996.

BACKGROUND: The aim of the study was to evaluate the isolation frequency and antibiotic susceptibility of pathogens isolated form urinocoltures. METHODS: 2192 bacterial strains obtained from urine cultures with bacterial count > 100,000 UFC/ml were examined in our Laboratory from July through December 1996. Inpatients as well as outpatients were considered. Five different ward typologies were taken into account (Surgery, Medicine, Obstetrics, Spinal Unit and High Risk Wards). Isolation frequencies were evaluated for each ward, but in order to get an adequate statistical sample they were divided into in two categories, e.g. strains isolated from inpatients and from outpatients. Antibiotic susceptibility was also evaluated dividing the data into the same two categories. For strains isolated with lower frequencies that was not possible, and data from inpatients were grouped with data from outpatients. RESULTS: The results obtained show that bacterial species most frequently isolated among inpatients are Escherichia coli (45.7%), Enterococcus faecalis (16.8%), Proteus mirabilis (9.1%), Pseudomonas aeruginosa (6.9%) and Klebsiella pneumoniae (6.4%). Those most frequently isolated among outpatients are Escherichia coli (58.1%), Enterococcus faecalis (12.3%), Proteus mirabilis (9.1%), Klebsiella pneumoniae (4.4%) and Coagulase negative staphylococci (4.0%). As far as antibiotic susceptibility is concerned, whenever a statistically significant difference in sensitivity could be observed between strains isolated from inpatients and strains isolated from outpatients, sensitivity was always higher for outpatients strains. CONCLUSIONS: Isolation frequency and antibiotic susceptibility are different depending on the place of origin of the patients (inpatients/outpatients). This implies a different approach to the empiric therapy in urinary tract infections.

Predictive value of a new osmotic test in the screening of heterozygous beta thalassemias.

A new osmotic test (time for 50% haemolysis in standard solution) has been applied in patients affected with heterozygous beta thalassemia in a population consisting of 19 thalassemic patients, 15 sideropenic patients, and 52 controls. The same population was examined for heterozygous beta thalassemia using electronic measurement of the erythrocyte indices. Sensitivity, specificity, predictive value and efficiency of the two tests were calculated. Statistical analysis did not show any significant differences in sensitivity and specificity between the two methods. The authors conclude that the osmotic test is sensitive, reliable and rapid; it seems to be a valid substitute for electronic haematology analysers in countries where they are not available.

[Cytochemical studies of bone marrow plasma cells in monoclonal gammapathies (author's transl)]. / Etude cyto-enzymologique des plasmocytes médullaires des dysglobulinémies monoclonales myélomateuses et non myélomateuses.

Three plasma cell enzymatic reactions--ATPase, acid phosphatase (AP), alpha-naphthyl acetate esterase (alpha-NAE)--were tested in a large number of bone marrow samples from patients with multiple myeloma (MM), benign monoclonal gammapathy (BMG)--idiopathic (iBMG) and secondary (sBMG)--, polyclonal hypergammaglobulinemia (PH), Waldenström's macroglobulinemia (WM) and from normoglobulinemic subjects (NS). The purpose of the present study was to evaluate the significance of these reactions in differential diagnosis of BMG and initial or atypical MM. For each reaction results were expressed as scores and normal limits were statistically established. Our findings in MM, HP and NS are consistent with previous reports (similar enzymatic pattern in NS and PH; depressed ATPase activity, raised AP and alpha-NAE activities in most MM cases). In the BMG class, ATPase activity was normal in about 40% of iBMG, while it was depressed in other cases; most sBMG had diminished ATPase activity. AP patterns were normal for both BMG groups. alpha-NAE activity was normal in 50% of iBMG, while it was raised in the other cases. All the reactions were normal in WM. In a bayesian analysis of cytochemical patterns of NS and MM subjects ATPase showed the highest diagnostic significance, followed by alpha-NAE and AP. ATPase, therefore, seems to be the most useful criterion for the diagnosis of initial MM; low ATPase score BMG patients should therefore be carefully followed-up.

Circadian study of immunoreactive prolactin in patients with cirrhosis of the liver.

The pattern of immunoreactive prolactin secretion over 24 hr in a group of patients suffering from cirrhosis of the liver has been studied and compared to that of healthy controls. The results were analyzed by use of chronograms and by mean cosinor. Although the daily mean average secretion of serum prolactin by the cirrhotics is not different from that of the control subjects utilizing the standard t-test, cosinor analysis of the data fails to demonstrate a circadian rhythm for prolactin secretion in the cirrhotics. These results are discussed in view of the apparent clinical hyperestrogenization and known changes in electrolyte balance which are commonly found in persons with advanced liver disease.

Chronobiological study on serum innumoreactive gastrin RIA levels in patients with liver cirrhosis.

After days of standardized conditions of life and standardized diets, serum gastrin levels were measured in 6 patients with liver cirrhosis on 3 consecutive days and in 14 normal controls on 1 day. Blood samples were drawn every 4 h. In patients as well as in controls, a significant serum gastrin circadian rhythm was noted. The daily mean serum gastrin levels of patients were not significantly different from those of controls. These results suggest a secondary role of the liver in gastrin metabolism.