[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.

Microbiological and pharmacokinetic evaluation of cefonicid, a long-acting cephalosporin.

The in vitro antimicrobial activity of cefonicid has been tested against 27 recent clinical isolates of 7 different species (S. aureus, E. coli, K. pneumoniae, P. mirabilis, S. marcescens, E. cloacae and P. aeruginosa) using the MS-2 Research System, contrast phase microscopy and the colony forming unit assay. With the exception of P. aeruginosa, S. marcescens and E. cloacae, cefonicid showed excellent activity against the different bacterial species tested (i.e. S. aureus, E. coli, K. pneumoniae and P. mirabilis). Tissue penetration of cefonicid after a single i.m. or i.v. dose (1 or 2 g, respectively) was also studied using the suction blister method. In 14 adult subjects with normal renal and liver functions, cefonicid plasma half-life was 5.1 and 5.4 h following i.v. and i.m. administration. Drug concentrations achieved at peak in plasma and suction blister fluid were higher than the minimum inhibitory concentrations for most sensitive pathogens and remained above these values for 24 h. These data support the use of a single daily dose regimen of cefonicid, both i.v. and i.m., for the treatment of most common infections caused by sensitive pathogens in blood and tissues.

[Frequency of isolation and drug resistance of bacterial strains from urine samples tested in the Bacteriology and Virology Laboratory of the U.S.L. 10/D in Florence]. / Frequenza di isolamento e chemioresistenza di stipiti batterici provenienti da campioni di urina esaminati presso il laboratorio di batteriologia e virologia dell'U.S.L. 10/D di Firenze.

Two thousand five hundred and sixty-eight positive monomicrobic urine samples (from general practice and hospital wards) were examined and isolated strains were tested against various antimicrobial drugs. Our findings showed that urinary-tract infections caused by Escherichia coli were the most common in females, whereas those by Pseudomonas aeruginosa, Proteus rettgeri, Enterobacter species, other difficult Gram-negative rods and Streptococcus faecalis were in total the most common in males. If we compare the strains isolated from general practice with those from the hospital, no significant differences were observed. E. coli strains were the most susceptible to the tested drugs; cefotaxime, amikacin, cefuroxime and ceftazidime were the most effective drugs against Enterobacter species, Ps. aeruginosa, P. rettgeri and Proteus mirabilis. P. mirabilis and Str. faecalis strains isolated in the hospital were more chemo-resistant than those isolated in general practice. Ampicillin and trimethoprim/sulphamethoxazole were less active against E. coli strains isolated from children's departments in comparison with the others.