High rates of community-acquired, Panton-Valentine leukocidin (PVL)- positive methicillin-resistant S. aureus (MRSA) infections in adult outpatients in Greece.

Staphylococcus aureus was isolated in 88 (30.8%) of 286 adult patients suffering from various skin and soft-tissue infections examined in the outpatient department of a 650 bed tertiary-care hospital of Athens, Greece between January 2006 and December 2007. Twenty-seven (30.7%) of the S. aureus infections were caused by methicillin-resistant S. aureus (MRSA). All MRSA isolates were also resistant to tetracycline, fucidic acid and kanamycin, but were sensitive to gentamicin and tobramycin, as well as to to cotrimoxazole, chloramphenicol, quinolones, clindamycin and erythromycin. All isolates belonged to staphylococcal cassette chromosome mec elements (SCCmec) type IV, and were found to carry the lukF-PV and lukS genes coding for Panton-Valentine leukocidin (PVL). Pulsed-field gel electrophoresis (PFGE) and spa-typing revealed high genetic similarity among all MRSA isolates and with the PFGE pattern of the well-described ST80 clone that seems to be spreading through Europe. The high prevalence of MRSA among S. aureus infections in the community signify that empiric therapy in Greece, when clinically indicated, should exclude beta-lactam antibiotics. Moreover, the establishment of an active screening for PVL-positive community-acquired (CA)-MRSA carriage and the adoption of a search and destroy strategy for CA-MRSA in all patients admitted with purulent skin and soft-tissue is of high priority in Greece as well as in all European countries which face high rates of CA-MRSA infection.

European surveillance study on antimicrobial susceptibility of Gram-positive anaerobic cocci.

Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of microorganisms frequently isolated from local and systemic infections. In this study, the antimicrobial susceptibilities of clinical strains isolated in 10 European countries were investigated. After identification of 299 GPAC to species level, the minimum inhibitory concentrations of penicillin, imipenem, clindamycin, metronidazole, vancomycin and linezolid were determined by the agar dilution method according to the Clinical and Laboratory Standards Institute. The majority of isolates were identified as Finegoldia magna and Parvimonas micra (formerly Peptostreptococcus micros), isolated from skin and soft tissue infections. All isolates were susceptible to imipenem, metronidazole, vancomycin and linezolid. Twenty-one isolates (7%) were resistant to penicillin (n=13) and/or to clindamycin (n=12). Four isolates were resistant to both agents. The majority of resistant isolates were identified as F. magna and originated from blood, abscesses and soft tissue infections.

Isolation of Clostridium difficile from patients and the environment of hospital wards.

Rectal swabs from 122 patients and 497 environmental swabs from several wards were examined for the presence of Clostridium difficile in order to assess the role of the environment in the spread of this organism. Clostridium difficile was isolated from 6/27 (22.2%) oncology patients and from 8/163 (4.9%) environmental specimens obtained from the oncology unit. Items found positive for C difficile were those subjected to faecal contamination such as commode chairs, bed pans, dust pans, discard bins, the sluice and a disposable bed pan machine. Fourteen of 51 (27.4%) asymptomatic neonates yielded mostly toxigenic C difficile in their stools during their first week of life. Five of 156 (3.2%) specimens taken from inanimate objects in the environment of the neonatal units were positive for C difficile. The organism was also isolated from the hands of a nurse. Similar antibiogram patterns were demonstrated in the strains obtained from the patients and their environment indicating the possible occurrence of cross infection. These results indicate that environmental contamination is important in the spread of C difficile in hospitalised patients and the implementation of isolation procedures may limit that spread.

Inhibition of Clostridium difficile by faecal streptococci.

The inhibitory activity of seven strains of faecal streptococci against 34 strains of Clostridium difficile was examined in vitro after growth of the streptococci for 24 and 48 h. All strains of C. difficile were inhibited at 48 h but at 24 h the inhibition was variable. Streptococcus faecium, a group D streptococcus and an ungroupable streptococcus exhibited the most striking inhibitory activity. Lowering of pH of the medium occurred at the site of inhibition, but the pH change alone did not explain the inhibition of C. difficile. This antagonism may be related in vivo to the resistance to intestinal colonisation by C. difficile exhibited by the normal bowel flora, and in vitro to failures to isolate C. difficile from faecal specimens.

Rapid diagnosis of anaerobic infections by gas-liquid chromatography.

It was postulated that the short chain fatty acids (SCFA) produced by anaerobic bacteria might serve as microbial markers in purulent material. Eighteen pus specimens from various sources were analysed by gas-liquid chromatography (GLC), and the SCFA detected were compared with the microorganisms isolated by conventional methods. It was found that the detection of propionic, isobutyric, butyric, or isovaleric acids by direct GLC of pus specimens is strong evidence for anaerobic infection but not specific for Bacteroides fragilis. It was also shown that the presence of succinic acid in pus specimens does not necessarily indicate infection by anaerobes. It can be concluded that direct GLC of purulent material provides a rapid and reliable presumptive method for the differentiation between anaerobic and aerobic infections.