The aim of this study was to determine the susceptibility patterns of 100 group B streptococcal strains isolated in our hospital and to ascertain tolerance to penicillin by determining quantitative killing curves. We found two strains with intermediate susceptibility to penicillin and eight strains to ampicillin. Seventeen isolates were tolerant to penicillin, with bacterial counts decreasing 2 to 3 log during the first 8 h but still above 10(2) CFU/ml after 24 h. The kinetic study shows that penicillin tolerance is not rare among group B streptococci isolated in our hospital.

The rates of resistance to erythromycin and clindamycin among Streptococcus agalactiae strains isolated in our hospital increased from 4.2 and 0.8% in 1993 to 17.4 and 12.1%, respectively, in 2001. Erythromycin resistance was mainly due to the presence of an Erm(B) methylase, while the M phenotype was detected in 3.8% of the strains. Telithromycin was very active against erythromycin-resistant strains, irrespective of their mechanisms of macrolide resistance.

The antimicrobial activities of tigecycline (GAR-936) were compared with those of other agents against 1,087 strains recently isolated in 12 Spanish medical centers. Tigecycline showed activity against a wide spectrum of aerobic and anaerobic bacteria, including strains such as methicillin-resistant Staphylococcus aureus, coagulase-negative staphylococci, penicillin-resistant Streptococcus pneumoniae, Enterococcus faecium, Acinetobacter baumannii, and Stenotrophomonas maltophilia.

The results of this study confirm the activity of tedizolid against linezolid-resistant staphylococci. This new oxazolidinone could have an important role as a potential therapeutic agent against multidrug-resistant staphylococci.

Listeria monocytogenes was isolated from the aqueous chamber of an immunodepressed patient with acute hypertensive uveitis, who developed a dark hypopyon and pigment dispersion. No extraocular septic focus was found. Treatment was successful with intravitreal vancomycin, anterior chamber irrigation with vancomycin, orally administered ciprofloxacin, and topical fortified vancomycin. CASE REPORTA 62-year-old man presented to the emergency department with pain, redness, and decreased vision in the left eye. The patient had a history of laryngeal carcinoma, for which he had undergone laryngectomy and had been treated with radiation therapy and steroids. Examination of the eye on admission revealed acute hypertensive uveitis, and treatment with corticosteroids was begun but did not provide significant improvement. The patient developed a dark hypopyon with pigment dispersion and uveal ectropion. A differential diagnosis was made between endogenous endophthalmitis and a neoplastic process of the ciliary body (either primary ciliary body melanoma or metastatic melanoma from larynx carcinoma). Results from laboratory studies were unremarkable, except for the leukocyte count (14,030/mm 3 with 77% polymorphonuclear neutrophils). The chest X ray was normal. Blood cultures were negative. An ultrasound scan of the eye showed dispersion of echoes, and no evidence of retinal detachment was noted. B-scan ultrasonography revealed inflammatory deposition and pigmentary epithelium detachment. No proliferation was detected in the stromal iris.Anterior chamber paracentesis was performed and submitted for culture and histopathology. Cytological examination showed polymorphonuclear leukocytes and no evidence of neoplastic cells. Because the patient reported a history of penicillin allergy, combined treatment with oral administration of ciprofloxacin (750 mg twice a day), anterior chamber irrigation with vancomycin, and intravitreal vancomycin (1 mg) was started. Topical fortified vancomycin (1 g) and corticotherapy were also applied. The patient's condition improved with treatment. Within 7 days, the hypopyon disappeared and the intraocular pressure decreased. However, visual acuity was limited to appreciation of hand motion, because of a severe corneal edema and a cataract which developed in the patient's left eye.A small amount of fluid obtained by aspiration from the anterior chamber was directly plated onto blood agar and chocolate agar and distributed into aerobic and anaerobic blood culture bottles processed by the BACTEC 9050 system (Becton Dickinson Microbiology Systems, Cockeysville, Md.). Gram staining was performed and no organisms were observed. After a 24-h incubation of plates at 35°C in a 5% CO 2 -enriched atmosphere, catalase-positive, gram-positive coccobacilli grew, producing beta-hemolysis on blood agar. The isolate was identified as Listeria monocytogenes by both the Wider system (Francisco Soria Melguizo, S.A., Madrid, Spain) and the API Listeria system (bioMérieux, Marcy l'Etoile, France). Pure culture of L. mon...