Comparative assessment of inoculum effects on the antimicrobial activity of amoxycillin-clavulanate and piperacillin-tazobactam with extended-spectrum beta-lactamase-producing and extended-spectrum beta-lactamase-non-producing Escherichia coli isolates.

A significant inoculum-size effect has been observed with piperacillin-tazobactam, and has been associated with beta-lactamase production in extended-spectrum beta-lactamase (ESBL) producers. This association has not been previously studied in the case of amoxycillin-clavulanate. Piperacillin-tazobactam and amoxycillin-clavulanate were compared, using high inocula of susceptible strains either harbouring ESBLs or not. Two non-ESBL-producing and 15 amoxycillin-clavulanate-susceptible and piperacillin-tazobactam-susceptible ESBL-producing Escherichia coli isolates, and their respective transconjugants, were tested in dilution susceptibility tests using standard and 100-fold higher inocula. Three ESBL-producing strains and E. coli ATCC 25922 were selected for time-kill studies using standard and high initial inocula. At high inocula, MICs of piperacillin increased >eight-fold for non-ESBL-producing strains, and MICs of piperacillin-tazobactam (8:1 ratio or with tazobactam fixed at 4 mg/L) increased>eight-fold for all ESBL-producing strains. However, amoxycillin MICs were not affected by a high inoculum with non-ESBL-producing strains, whereas the MICs of amoxycillin-clavulanate (2:1 and 4:1) increased

[Abdomino-pelvic actinomycosis associated with an intrauterine device. Apropos of a case]. / Actinomicosis abdomino-pélvica asociada al dispositivo intrauterino. A propósito de un caso.

PIP: Although over 300 cases of pelvic actinomycosis have been published, it was not until 1973 that the 1st case of pelvic actinomycosis associated with the new generation of IUDs was described. Data is provided in this article on the causative agent, laboratory procedures, surgical excision, and pathological studies in 1 case of abdominal-pelvic actinomycosis, and the findings are compared to other reports in the English and Spanish literature. A multipara of 25 years with fever, metrorrhagia, and painful tumoration began to suffer dysmenorrhea in June 1980 but attributed the symptoms to the Copper 250 Multiload IUD she had used since July 1979. A laparotomy in December 1980 disclosed the infection, and pathological tests confirmed the diagnosis. The exact incidence of the association of actinomycosis and the IUD is not known, but the microorganism, Actinomyces-Israeli, is more common in wearers of IUDs than in other women. The diagnosis of actinomycosis is confirmed through microbiological study and histological identification. Treatment since 1945 has consisted of large doses of penicillin over long periods of time, but the use of other antibiotics including tetracycline and erythromycin has been introduced. The abscess or abscesses should be excised and the IUD removed in cases where a relationship is suspected.^ieng