In order to assess the current level of resistance to widely used antipseudomonal antibiotics in clinical isolates of Pseudomonas aeruginosa, a national survey was undertaken. Fifteen hospitals throughout Italy participated in the study. The University of Catania tested the antibiotic susceptibility of 1005 consecutive clinically significant P. aeruginosa collected from March to June 1995. Lack of susceptibility, according to NCCLS breakpoints, was at the following rates: meropenem, 9.1%; imipenem, 19.3%; ceftazidime, 13.4%; carbenicillin, 27.3%; piperacillin, 12%; ticarcillin/clavulanic acid, 22.8%; amikacin, 10.6%; and ciprofloxacin, 31.9%. About half of the isolates (44.4%) were not susceptible to at least one of the antibiotics tested.

Summary. Xanthomonas maltophilia produces two inducible P-lactamases, L 1 and L2, and resists the antimicrobial activity of P-lactam antibiotics, including carbapenems. L1 is a zinc-metaloenzyme with carbapenemase activity; L2 is an unusual cephalosporinase. Mutant strains with high-and low-level constitutive expression of these enzymes were derived from three reference strains of X. maltophilia. With a single exception, the mutant strains had altered expression of both enzymes, indicating that these P-lactamases share regulatory components. The exception was a mutant strain that had low-level constitutive (basal) expression of L1 enzyme but remained inducible for L2. A parent strain with low-level Blactamase inducibility was more susceptible to penicillins, cephalosporins and carbapenems than were those in which higher levels of enzyme activity were inducible. Mutations that caused high-level constitutive P-lactamase expression increased resistance to penicillins and newer cephalosporins. P-Lactamase basal mutant strains, including the one that remained inducible for L2 enzyme, were more susceptible than inducible strains to these drugs. Organisms with inducible or high-level constitutive P-lactamase expression were equally resistant to meropenem and imipenem but basal mutant strains, including the one that remained inducible for L2 enzyme, were more susceptible to meropenem than imipenem. Minimal inhibitory concentrations of meropenem, penicillins and cephalosporins, but not imipenem, were greater on Mueller Hinton agar than on IsoSensitest or Diagnostic Sensitivity Test agars. This behaviour was independent of P-lactamase inducibility, and may reflect permeability differences between cells grown on different media.

Cognitive impairment, as well as mood and anxiety disorders, occur frequently in patients following stroke. Aim of this study was to evaluate the effects of a combined rehabilitative treatment using conventional relaxation and respiratory techniques, in a specific rehabilitative virtual environment (by using Bts-Nirvana). A 58-year-old woman, affected by hemorrhagic stroke, underwent two different rehabilitation trainings, including either standard relaxation techniques alone in a common clinical setting or the same psychological approach in a semi-immersive virtual environment with an augmented sensorial (audio-video) and motor feedback (sensory motor-interaction). We evaluated the patient's cognitive and psychological profile before and after the two different trainings, by using a specific psychometric battery, aimed to assess cognitive status, attention processes and to estimate the presence of mood alterations, anxiety and coping strategies. Only at the end of the combined approach, we observed a significant improvement in attention and memory functions, with a nearly complete relief of anxiety symptoms and an improvement in coping strategies. Relaxation and respiratory techniques in a semi-immersive virtual reality environment, using Bts-Nirvana, may be a promising tool in improving attention process, coping strategies, and anxiety in individuals with neurological disorders, including stroke.

Eighty-one patients with clinical diagnosis of aerobic vaginitis (AV) were included in the study. The patients were randomized for treatment, 45 with kanamycin (100 mg vaginal ovules for 6 days, consecutively) and 36 with meclocycline (35 mg vaginal ovules for 6 days, consecutively). The patients were examined before starting the study, 1-2 days after treatment and 30 days after the end of the study. At the first follow-up the patients showed different levels of symptom reduction. Reduction in the presence of leukocytes, vaginal mucosa burning and itching were statistically significant in the group treated with kanamycin with respect to the group treated with meclocycline. Moreover, there was also reduced isolation of Enterobacteriaeae (97%) in the group treated with kanamycin versus those treated with meclocycline (76%). At the second follow-up, vaginal homeostasis (normalization of pH and presence of lactobacilli) was more evident in the kanamycin-treated group. In conclusion, our data suggest that the topical use of kanamycin could be considered a specific antibiotic for the therapy of this new pathology.

The mechanisms of resistance to beta-lactam antibiotics in 325 isolates of Pseudomonas aeruginosa were examined. These isolates were selected because of their resistance to meropenem and imipenem (breakpoint, >4 mg/L), carbenicillin (>128 mg/L), ceftazidime (>8 mg/L), piperacillin and ticarcillin/clavulanate (>64 mg/L). The most frequent mechanism of resistance was beta-lactamase-independent, so called 'intrinsic resistance', which was found in 183 isolates and was probably due to impermeability and/or efflux mechanisms. beta-Lactamase-mediated resistance was demonstrated in 111 strains (11.1%). Derepression of Ambler Class C chromosomal beta-lactamase was detected in 64 isolates, most of which were resistant to ceftazidime and piperacillin but susceptible to meropenem, whereas secondary plasmid-encoded beta-lactamases were found in 34 isolates, all of them resistant to carboxypenicillins and ureidopenicillins and susceptible to carbapenems. Twelve strains showed more than one plasmid-encoded beta-lactamase plus derepression of chromosomal Class C enzyme. Resistance to carbapenems was independent of resistance to other beta-lactam antibiotics, indicating a different mechanism of resistance, probably due to the loss of the D2 porin. In total, 32 strains were resistant to carbapenems: 24 only to imipenem and eight to both imipenem and meropenem.

The in vitro activity of rufloxacin (MF 934), a new broad-spectrum fluoroquinolone, was tested against 1,032 gram-positive and gram-negative clinical isolates and compared to that of five other compounds of this class. All quinolones except for ciprofloxacin had limited activity against group A and B streptococci and pneumococci (MIC 90% of 4–64 mg/l) and no activity against enterococci. Most species of the enterobacteriaceae and staphylococci were found to be sensitive to rufloxacin (MIC 90% of 0.5–8 and 2–8 mg/l). Like the other quinolones except for ciprofloxacin, rufloxacin was not active against Pseudomonas aeruginosa.The antibacterial activity of rufloxacin was affected only minimally by an increase in the bacterial inoculum or by alterations in the pH of the medium. In spite of the relatively higher MICs of rufloxacin compared to those of the other quinolones, its favorable pharmacokinetic properties may account for its good clinical efficacy.

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The beta-lactamases produced by Acinetobacter lwoffii ULA-501, Acinetobacter baumannii ULA-187, and A. baumannii AC-14 strains were purified and characterized, and their kinetic interactions with several beta-lactam molecules, including substrates and inhibitors, were studied in detail. The three enzymes appeared to be cephalosporinases with different acylation efficiencies (kcat/Km ratio values), and their hydrolytic activities were inhibited by benzylpenicillin, piperacillin, and cefotaxime, which did not behave as substrates. Carbenicillin was a substrate for the beta-lactamase from A. lwoffii ULA-501, whereas it acted as a transient inactivator of the enzymes produced by the two A. baumannii strains. Clavulanic acid was unable to inactivate the three beta-lactamases, whereas sulbactam behaved as an inactivator only at a high concentration (1 mM) which is difficult to achieve during antibiotic therapy. Analysis of the interaction with 6-beta-iodopenicillanic acid also allowed us to better discriminate the three beta-lactamases analyzed in the present study, which can be included in the group 1 functional class (5).