Phenotypic and molecular characterisation of multiresistant monophasic Salmonella Typhimurium (1,4,[5],12:i:-) in Greece, 2006 to 2011.

Recently, multiresistant Salmonella enterica serovar1,4,[5],12:i:-, a monophasic variant of S. Typhimurium(1,4,[5],12:i:1,2) emerged, and is now among the most common serovars isolated from humans in many countries.In Greece, monophasic Typhimurium which was recorded for the first time in human isolates in 2007(0.3% of total isolates), increased sharply thereafter,and since 2009 is the third most frequent serovar. In the present study, 119 S. enterica 1,4,[5],12:i:- strains of human, animal and food origin, isolated during the period between 2006 and 2011, were examined.Strains verified as monophasic Typhimurium variants by polymerase chain reaction (PCR) (97 strains), were further characterised by phenotypic (antibiotic resistance and phage typing) and molecular (pulsed-field gel electrophoresis ­ PFGE) methods. The results indicate that multiple clones of multiresistant monophasic Typhimurium are circulating in Greece. The most frequently encountered clone in humans and pigs was that of phage type DT120, R-type ASSuTSpTm and PFGEprofile STYMXB.0010, while in poultry other clones were detected. The data indicate that pigs may be a reservoir of this clone in Greece.

KPC-2-producing Klebsiella pneumoniae infections in Greek hospitals are mainly due to a hyperepidemic clone.

To verify the presence of Klebsiella pneumoniae carbapenemase-producing (KPC-producing) Klebsiella pneumoniae in Greece, we asked 40 Greek hospitals participating in the Greek System for the Surveillance of Antimicrobial Resistance (GSSAR) to apply a combination of the modified Hodge test plus EDTA synergy test on all K. pneumoniae clinical isolates obtained from February 2008 which displayed reduced susceptibility to carbapenems (MIC of imipenem > or = 1 mg/L). The presence of the blaKPC gene was confirmed by PCR and sequencing. This procedure revealed the presence of KPC-2 in isolates from 173 patients in 18 hospitals during a period of 11 months. Of these, 166 isolates belonged to a single pulsotype a fact consistent with possible epidemic spread, whereas the remaining seven isolates were further classified into four different pulsotypes. BlaKPC-2 gene was found to be transferable by conjugation in the four pulsotypes other than the prevailing one. The emergence of a new carbapenemase gene in Greece, where high resistance rates to carbapenems in K. pneumoniae due to the spread of the VIM type metalloenzyme have been observed, emphasises the urgent need for the implementation of public health measures in the field of infection control and antibiotic consumption. It also underlines the need to supplement surveillance systems based on susceptibility data with the surveillance of resistance mechanisms.

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.

Epidemiology of metalloenzyme-producing Pseudomonas aeruginosa in a tertiary hospital in Greece.

A total of 132 infections of Pseudomonas aeruginosa (including 112 imipenem resistant, 32 of them producing VIM-2 beta-lactamase) were identified during a one-year period (June 2002-June 2003). PFGE molecular typing revealed that P. aeruginosa clinical isolates sensitive to imipenem, P. aeruginosa isolates resistant to imipenem but VIM-negative, and P. aeruginosa-resistant and VIM-positive isolates could be allocated to three different clusters with approximately 70% similarity. A case control study of patients infected with an MBL-producing imipenem-resistant P. aeruginosa isolate and controls (patients hospitalized in the same time period with no infection), revealed that only the number of catheters present at the time of the infection was strongly associated with the development of infection due to VIM-producing P. aeruginosa (OR 4.83, 95% CI: 1.94-12.0). In conclusion, the results of the molecular typing combined with the results of the case control study indicate that in the specific hospital setting, infection control, addressed specifically to critically ill patients, is an important part of any strategy to reduce imipenem-resistant infections.

Trends in antimicrobial resistance of Acinetobacter baumannii clinical isolates from hospitalised patients in Greece and treatment implications.

This study analysed the proportions of Acinetobacter baumannii isolates resistant to various antibiotics that were recovered from patients hospitalised in Greek hospitals between 1996 and 2006. The microbiological data were derived from the ongoing WHONET Greek System for the Surveillance of Antibiotic Resistance. There were increases in the proportions of A. baumannii isolates resistant to imipenem from patients hospitalised in intensive care units, medical wards and surgical wards during the study period from 0% to 91%, 8% to 71%, and 5% to 71%, respectively.

Emergence of Proteus mirabilis carrying the bla metallo-beta-lactamase gene.

Seven genetically related Proteus mirabilis clinical isolates from a hospital in Thessaloniki, Greece, exhibited decreased susceptibility to imipenem and carried a bla(VIM-1) metallo-beta-lactamase gene. PCR mapping revealed that bla(VIM-1) was part of a class 1 integron that was probably located in the chromosome and also included the aacA7, dhfr and aadA genes. This is the first description of the bla(VIM-1) metallo-beta-lactamase gene in P. mirabilis.

Community acquired MRSA infections in a paediatric population in Greece.

We investigated the characteristics of 20 community acquired methicillin resistant Staphylococcus aureus (MRSA) strains isolated in a paediatric hospital in Athens. Eighteen of these, all isolated from skin and soft tissue infections, carried the Panton-Valentine leukocidin (PVL) determinants. They all were found resistant to fusidic acid, tetracycline and kanamycin, and displayed a PFGE pattern identical to that of the well-described ST80 CA-MRSA clone circulating in various European countries.