Cluster of cases of Salmonella enterica serotype Rissen infection in a general hospital, Italy, 2007.

In 2007, three strains of Salmonella enterica serotype Rissen (S. Rissen) were isolated in the laboratory of diagnostic microbiology of the General Hospital of Prato, Tuscany, Italy, over a 1 month and half interval of time. The first isolate was recovered on January 26 from an outpatient with enteritis. Then, two strains were isolated on February 16 and March 11 respectively, from central venous catheters of patients who were being hospitalized in two departments of the Hospital. An epidemiologically linked cluster of cases of salmonellosis was suspected. The three strains were submitted to single enzyme-amplified fragment length polymorphism (SE-AFLP) and XbaI macrorestriction and pulsed-field gel electrophoresis (PFGE) that yielded undistinguishable profiles. Epidemiological investigations failed to identify a common source of infection within the Hospital. Moreover, the third patient had been exclusively total parenteral nutrition fed since his admission with a stomach cancer diagnosis. The first patient had a community-acquired infection, but the source of her illness was uncertain. Twenty-five further isolates identified in the years 2004-2007 in the same geographical area showed distinctly different PFGE and SE-AFLP patterns. The three patients seemed to represent a cluster of epidemiologically unrelated cases caused by a previously never recognized S. Rissen strain. Rapid subtyping of isolates is essential in the early investigation of potential outbreaks, but synthesis of conventional and molecular epidemiological investigation and availability of surveillance data is often critical to prevent the initiation of time-consuming, expensive and ineffective further investigations and control interventions.

Multicenter randomized trial comparing meropenem (1.5 g daily) and imipenem/cilastatin (2 g daily) in the hospital treatment of community-acquired pneumonia.

An open, multicenter study with 144 patients, aged between 18 and 94 years, was performed to compare the efficacy and safety of meropenem with imipenem/cilastatin in the hospital treatment of community-acquired pneumonia. Patients were randomized to receive either intravenous meropenem (500 mg every 8 h) or intravenous imipenem/cilastatin (1,000 mg every 12 h). The primary end point was considered to be clinical efficacy and the secondary end points were bacteriological response and safety assessment. At the end of therapy, cure or improvement in signs and symptoms as a satisfactory clinical response was observed in 57 of 64 (89.1%) meropenem-treated patients and in 60 of 66 (90.9%) imipenem/cilastatin patients. The mean duration of treatment was 10 days for meropenem and 9.7 days for imipenem/cilastatin. In patients who were followed up for weeks 2-4, the response was satisfactory (100%) for both treatments. A satisfactory bacteriological response, defined as either presumed or confirmed eradication of all pathogens, was found in eight patients who had received meropenem and in 14 patients who had received imipenem/cilastatin. Response was considered satisfactory in 100% of the meropenem group and in 92.9% of the imipenem/cilastatin group and at follow-up, it was 100% for both treatments. Drug-related adverse events were reported in three (4.2%) meropenem-treated patients and in eight (11.0%) imipenem/cilastatin-treated patients. None of these events was classified as serious. The results of this study show that the clinical and bacteriological efficacy and tolerability of meropenem (500 mg every 8 h) are similar to that of imipenem/cilastatin (1,000 mg every 12 h) in the hospital treatment of community-acquired pneumonia.