Molecular epidemiology of meticillin-resistant Staphylococcus aureus in Italian cystic fibrosis patients: a national overview.

BACKGROUND: The genetic background, transmissibility and virulence of MRSA have been poorly investigated in the cystic fibrosis (CF) population. The aim of this multicentre study was to analyse MRSA strains isolated from CF patients attending nine Italian CF care centres during a two-year period (2004-2005). All CF patients infected by MRSA were included. METHOD: Antibiotic susceptibility testing, SCCmec typing, Panton-Valentine Leukocidin (PVL) production, and Multi Locus Sequence Typing (MLST) analysis were carried out on collected isolates (one strain per patient). RESULTS: One hundred and seventy-eight strains isolated from 2360 patients attending the participating centres were analysed. We detected 56 (31.4%) SCCmec IV PVL-negative strains, with a resistance rate of 80.3% to clindamycin and of 14.5% to trimethoprim/sulphamethoxazole. MLST analysis showed that many isolates belonged to known epidemic lineages. The largest clone grouping of 29 isolates from 6 centres had the genetic background (ST8-MRSA-IV) of the American lineages USA300 and USA500, thus demonstrating the diffusion of these strains in a population considered at risk for hospital associated infections. CONCLUSIONS: Known MRSA epidemic clones such as USA600, USA800, USA1100, and UK EMRSA-3 were described for the first time in Italy. The diffusion of MRSA strains with high pathogenic potential in the CF population suggests that analysis of the MRSA strains involved in pulmonary infections of these patients is needed.

Transmission of Burkholderia cepacia complex: evidence for new epidemic clones infecting cystic fibrosis patients in Italy.

To analyze national prevalence, genomovar distribution, and epidemiology of the Burkholderia cepacia complex in Italy, 225 putative B. cepacia complex isolates were obtained from 225 cystic fibrosis (CF) patients attending 18 CF centers. The genomovar status of these isolates was determined by a polyphasic approach, which included whole-cell protein electrophoresis and recA restriction fragment length polymorphism (RFLP) analysis. Two approaches were used to genotype B. cepacia complex isolates: BOX-PCR fingerprinting and pulsed-field gel electrophoresis (PFGE) of genomic macrorestriction fragments. A total of 208 (92%) of 225 isolates belonged to the B. cepacia complex, with Burkholderia cenocepacia as the most prevalent species (61.1%). Clones delineated by PFGE were predominantly linked to a single center; in contrast, BOX-PCR clones were composed of isolates collected either from the same center or from different CF centers and comprised multiple PFGE clusters. Three BOX-PCR clones appeared of special interest. One clone was composed of 17 B. cenocepacia isolates belonging to recA RFLP type H. These isolates were collected from six centers and represented three PFGE clusters. The presence of insertion sequence IS 1363 in all isolates and the comparison with PHDC reference isolates identified this clone as PHDC, an epidemic clone prominent in North American CF patients. The second clone included 22 isolates from eight centers and belonged to recA RFLP type AT. The genomovar status of strains with the latter RFLP type is not known. Most of these isolates belonged to four different PFGE clusters. Finally, a third clone comprised nine B. pyrrocinia isolates belonging to recA RFLP type Se 13. They represented three PFGE clusters and were collected in three CF centers.

Comparison of the MB/BacT and BACTEC 460 TB systems for recovery of mycobacteria from various clinical specimens.

A total of 1,830 specimens (75.7% respiratory and 24.3% nonrespiratory) were cultured in parallel with the MB/BacT and BACTEC 460 TB systems and on Lowenstein-Jensen (LJ) medium. Mycobacteria were identified from 173 (6.5%) specimens. The most common species recovered were Mycobacterium tuberculosis complex (65. 9%), Mycobacterium avium complex (22.5%), and Mycobacterium chelonae (9.2%). The recovery rates by individual systems were 96.5, 99.4, and 95.9% for MB/BacT, BACTEC 460 TB, and LJ medium, respectively, for all mycobacteria; the recovery rates were 99.1, 100, and 98.2%, respectively, for M. tuberculosis complex alone. The difference among the recovery rates for all mycobacteria and those for individual species was not significant. The BACTEC 460 TB system detected M. tuberculosis isolates more rapidly than the MB/BacT system (8 versus 11.8 days for smear-positive specimens [P < 0.01] and 18 versus 21 days for smear-negative specimens [P < 0.05]), whereas the MB/BacT system more rapidly detected the nontuberculous mycobacteria (17.1 versus 12.7 days [P < 0.01]). These results indicate that the nonradiometric MB/BacT system is a rapid, sensitive, and efficient method for the recovery of M. tuberculosis and nontuberculous mycobacteria from both pulmonary and extrapulmonary clinical specimens.

Field inversion gel electrophoresis on Pseudomonas cepacia strains isolated from cystic fibrosis patients.

Genome fingerprinting by field inversion gel electrophoresis (FIGE) was utilized to typify 129 isolates of Pseudomonas cepacia (Pc) from 59 patients with cystic fibrosis (CF) and from environmental cultures in the CF ward. The aim of this study was to assess whether a segregation policy avoided colonization of CF patients by nosocomial strains and contamination of the environment by colonized individuals, whether or not an 'epidemic strain' was present in the ward and whether cross-colonization occurred in CF individuals subjected to prolonged close contact. The Pc strains of each patient remained unchanged over time; 78% of the genome finger printings (GFP) were individual, whereas the others gave rise to 9 GFP groups. A spirometer was probably contaminated by a newly colonized patient. Adequate sanitary measures and avoidance of excessive promiscuity are helpful for limiting but are unable to eliminate Pc transmission in the CF ward. Direct or indirect transmission, however seems, more frequent in CF patients in contacts outside the hospital.

Comparison of four in vitro assays for specific IgE detection.

Three immunoenzymatic techniques for specific IgE detection (Pharmacia CAP System, Kallestad Allercoat System, Neo Abellò Hamlet-IgE) and the classical Phadebas RAST were compared using 34 sera from patients with a clinical diagnosis of allergic disease and 19 sera from healthy non-atopic controls. IgE antibodies to 9 aeroallergens and 6 food antigens were assessed and 399 tests were run with each method. All techniques showed a high specificity (92%-100%) and satisfactory efficiency (82%-98%), while the sensitivity for RAST, CAP, Allercoat and Hamlet was 89%, 91%, 83% and 53%, respectively, with the lowest values for food allergens. There was a good overall correlation of the four techniques, except when the Hamlet method was compared with the other methods for food-specific IgE detection (correlation coefficient < 0.3). These data indicate that CAP, Allercoat and RAST are satisfactory techniques for specific IgE determination, either for inhalants or for food allergens; CAP, however, offers the highest sensitivity without loss of specificity.

Controlled study of oxatomide vs disodium chromoglycate for treating adverse reactions to food.

A controlled, cross-over trial was carried out to compare the efficacy and safety of oxatomide vs disodium chromoglycate (DSCG) for treating food allergy and intolerance. Twenty patients (15F, 5M; mean age 36.6 years), with chronic urticaria (twelve patients) or eczema (eight patients) caused by food allergy (ten cases) or food intolerance (ten cases), were treated with oxatomide (60 mg/day in a single evening administration) and with DSCG (2000 mg/day) for six weeks. The two treatments were separated by a 3-week wash-out period. All the patients completed the trial. During the treatment, both drugs succeeded in controlling the symptoms. With oxatomide, the wheals totally disappeared from 75% of the patients (p = 0.00135), the eczematous lesions disappeared from 64% (p = 0.056), and the itching from 70% (p = 0.00012); the figures for DSCG were 33%, 50% (p = 0.038) and 50%, respectively. Both drugs were well tolerated and there was no need to discontinue the treatment of any of the patients.

Double-blind cross-over trial of oral sodium cromoglycate in patients with irritable bowel syndrome due to food intolerance.

Twenty patients with irritable bowel syndrome due to food intolerance were randomized to either oral sodium cromoglycate or placebo in a double-blind cross-over trial. The study consisted of treatment with either sodium cromoglycate or placebo for 8 weeks, followed by the cross-over treatment for 8 further weeks. Patients were allowed to eat the offending foods during the study. Eighteen patients completed the study. Analysis of patients' diary card scores showed a statistically significant difference in favour of sodium cromoglycate. There was a long carry-over effect in the active-placebo order group. Therefore oral sodium cromoglycate seems to be a useful treatment in patients with irritable bowel syndrome and proven food intolerance.

[Prevalence of food allergy in patients with urticaria-angioedema syndrome]. / Prevalenza dell'allergia alimentare in pazienti affetti da sindrome orticaria-angioedema.

We have studied 239 patients, 53 males and 186 females, mean age 31.9, affected by urticaria-angioedema syndrome. Fifty-three patients didn't complete the study. One-hundred-three of the other 186 patients went on elimination diet: 111 patients suffered from chronic urticaria-angioedema syndrome and 21 subjects suffered from acute syndrome. Eighty-one out of the 132 patients obtained good results from dietetic management (p less than 0.001). Double blind challenge test was positive in 42 subjects: 29 patients suffered from Food Allergy and 13 patients from Food Intolerance. Thus, the prevalence of Food Allergy in patients who completed dietetic management was 21.9% (29 patients out of 132). If we evaluate all the 186 patients affected by urticaria-angioedema syndrome, the prevalence of Food Allergy is 15.5%.