Ticarcillin/clavulanic acid: determination of minimal inhibitory concentrations against bacterial strains isolated from patients in intensive care units. Comparison with other agents.

A total of 303 bacterial strains isolated from bronchoaspirates of Intensive Care Unit (ICU) patients, collected through June and December 1993, were tested for susceptibility to ticarcillin/clavulanic acid, imipenem, amikacin, ceftazidime, ciprofloxacin and piperacillin. The minimal inhibitory concentration (MIC) for each antibiotic was determined according to the NCCLS, by means of serial dilution on microplates. The isolates, 80.8% of which were beta-lactamase producing strains, belonged to Pseudomonas aeruginosa (79 strains), Pseudomonas fluorescens (8 strains), Xanthomonas maltophila (25 strains), Escherichia coli (16 strains), Klebsiella-Enterobacter-Serratia (KES) (62 strains), Proteus spp. (15 strains), Acinetobacter spp. (22 strains), Moraxella spp. (15 strains), Bacteroides catarrhalis (8 strains), Haemophilus spp. (11 strains), Staphylococcus aureus (32 strains), Enterococcus faecalis (10 strains). The highest rate of susceptibility to ticarcillin/clavulanic acid (100%) was detected among E. faecalis (MIC 2-16 micrograms/ml), B. catarrhalis (MIC 1-4 micrograms/ml) and Haemophilus spp. (MIC 1-4 micrograms/ml). Among the non-fermenting microorganisms ticarcillin/-clavulanic acid showed good activity toward P. aeruginosa and P. fluorescens (86% and 75% respectively). It was also very active against X. maltophilia with a susceptibility of 96%. Susceptibility to the other antibiotics tested was within the range of 16% and 28%.

Singular case of tardive anastomotic disjunction in a Dacron R vascular graft.

We investigated a case of anastomotic disjunction of the termino-lateral insertion of a bifurcate aortic graft in the right external iliac artery. The graft in woven Dacron R n. 19, was implanted in 1977 and the left femoral insertion became infected shortly after surgery. The infection was treated according to standard procedures with removal of the infected branch, reconstruction with the transobturatory by-pass and antibiotics. For antibiotic treatment of local and general sepsis the approach was completely new as regards dose regimen and duration. In 1993 a pseudoaneurysm developed through weakening of the right iliac anastomosis. In view of the anamnesis we were surprised to find that the origin was of a mechanical nature.

[Importance of Staphylococcus epidermidis in the bacterial colonization of abdominal drains in surgical patients]. / Rilevanza dello Staphylococcus epidermidis nella colonizzazione batterica dei drenaggi addominali in pazienti chirurgici.

Bacterial adherence to biomaterials as an element of clinical relevance is a well-known factor in the pathogenesis of sepsis. Drainages, intravascular catheters, surgical prostheses and other devices are susceptible to bacterial colonization with clinical consequences. In the last few years attention has been paid to coagulase-negative Staphylococcus (S. epidermidis), mainly to some strains able to produce a highly adhesive polysaccharide substance, called glycocalix or slime. This promotes adherence either interbacterial either between bacteria and biologic tissues or synthetic materials acting as a pathogenetic factor in sepsis being able to increase bacterial resistance to phagocytes and antibiotics. Bacterial contamination of 40 abdominal drainage tubes in patients operated in elective and in emergency surgery for various pathology has been evaluated. Sonication of the tip of the drainage was utilized in order to promote the detachment of adherent colonies and its effectiveness was compared to that of microcentrifugation. Culture of 25 drainages (62.5%) showed no bacterial contamination; 7 drainages (17.5%) have proved to be colonized by S. epidermidis, in 4 cases the isolated strains were also methicillin-resistant, 2 of which slime-producing. Out of the 7 drainages colonized by S. epidermidis, 4 were removed from patients operated in emergency: none of the isolated strains was slime-producing. Six drainages (15%) were colonized by Gram+ bacteria (S. fecalis, P-sensible cocci, rods), 1 (2.5%) by E. coli and 1 (2.5%) by P. aeruginosa, S. epidermidis appears to be the chief contaminant of abdominal drainages, especially in emergency surgery; slime production has always been observed in methicillin-resistant strains: this confirms the hypothesis that slime production is typical of specialized, virulent strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Ciprofloxacin for infection prophylaxis in granulocytopenic patients with acute leukemia.

Forty consecutive neutropenic patients with acute leukemia receiving oral ciprofloxacin (500 mg twice daily) and ketoconazole (200 mg daily) for selective intestinal decontamination were compared retrospectively with 33 comparable patients treated with polymyxin E (1,500,000 U x 3/day) and nystatin (1,000,000 U x 3/day). The incidence of febrile episodes was slightly lower in ciprofloxacin treated patients (87.5% vs 100%). No gram-negative sepsis was observed in this group compared with seven cases in patients receiving polymyxin E (p less than 0.01). Furthermore, eight patients in ciprofloxacin group (20%) had gram-positive sepsis, compared with five (15.5%) in the polymyxin E group. The incidence of documented fungal infections was similar in the two groups. Ciprofloxacin appears to be an effective agent for the prevention of gram-negative infections in granulocytopenic patients with acute leukemia, but may contribute to a shift in the type of infections in these patients towards those caused by gram-positive microorganisms, intrinsically fairly sensitive or with acquired drug resistance.

[Evaluation of a screening method for the rapid detection of bacteriuria]. / Valutazione di un apparato per lo screening rapido delle batteriurie.

A screening method for the rapid detection of bacteriuria through a combination of filtration and staining has been evaluated. 307 urine samples have been tested with both the regular colony enumeration on culture media and the rapid method. Taking 10(5) CFU/ml as a cut-off, the agreement was reached for 279 (90.9%) samples, 65 (21.2%) of which positive and 214 (69.7%) negative. Only 4 (1.3%) false negative and 24 (7.8%) false positive were obtained; false positive (whose real significance is further discussed) anyhow can be corrected after cultural confirmation. If the cut-off is lowered to 10(4) CFU/ml the frequency of agreements is slightly less (88.6%). From the operational side, the method is unsensitive to the antimicrobial content of the urines, and appears easy to apply and quite rapid: a sample needs not longer than 2 minutes to be processed.

[Unusual pathology caused by Salmonella in the Greater Hospital of Milan in the 3-year period of 1977-1979]. / Patologia inusuale da salmonelle nell'Ospedale Maggiore di Milanoi nel triennio 1977-79.

At the Central Laboratory of the Medical School, University of Milano, Italy, 44 Salmonella strains were isolated from morbid materials other than stools during the three-years period 1977-79 (blood 26, urine 6, pus 3, pleural fluid 4, bile 3, upper respiratory mucus 2). In the present paper, nine cases of Salmonella infections, selected for their unusual localization a/o their peculiar clinical onset, are reviewed. From most of the clinical histories it appears that, in quite a few occasions, the episode due to Salmonella has been favoured or conditioned by a preexisting disease, therefore suggesting a nosocomial-type event. It also appears that the help from the microbiologist was often requested less than promptly, and minimal requirements for its efficacy were seldom achieved.

[Isolation and serotyping of Streptococcus pneumoniae]. / Isolamento e sierotipizzazione di Str. pneumoniae.

87 strains of Str. pneumoniae were typed by serology and a chemoantibiotic resistance assay was made. Among them, the most frequent serological types are 4, 6, 7, 19, 33. None of these has shown a marked chemoantibiotic resistance and no prevalent resistance has been related to a particular specimen.