Microbiological diagnostics of bloodstream infections in Europe-an ESGBIES survey.

OBJECTIVES: High-quality diagnosis of bloodstream infections (BSI) is important for successful patient management. As knowledge on current practices of microbiological BSI diagnostics is limited, this project aimed to assess its current state in European microbiological laboratories. METHODS: We performed an online questionnaire-based cross-sectional survey comprising 34 questions on practices of microbiological BSI diagnostics. The ESCMID Study Group for Bloodstream Infections, Endocarditis and Sepsis (ESGBIES) was the primary platform to engage national coordinators who recruited laboratories within their countries. RESULTS: Responses were received from 209 laboratories in 25 European countries. Although 32.5% (68/209) of laboratories only used the classical processing of positive blood cultures (BC), two-thirds applied rapid technologies. Of laboratories that provided data, 42.2% (78/185) were able to start incubating BC in automated BC incubators around-the-clock, and only 13% (25/192) had established a 24-h service to start immediate processing of positive BC. Only 4.7% (9/190) of laboratories validated and transmitted the results of identification and antimicrobial susceptibility testing (AST) of BC pathogens to clinicians 24 h/day. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry from briefly incubated sub-cultures on solid media was the most commonly used approach to rapid pathogen identification from positive BC, and direct disc diffusion was the most common rapid AST method from positive BC. CONCLUSIONS: Laboratories have started to implement novel technologies for rapid identification and AST for positive BC. However, progress is severely compromised by limited operating hours such that current practice of BC diagnostics in Europe complies only partly with the requirements for optimal BSI management.

Nationwide survey of CTX-M-type extended-spectrum beta-lactamases among Klebsiella pneumoniae isolates in Slovenian hospitals.

Among 177 extended-spectrum beta-lactamase-producing Klebsiella pneumoniae isolates collected from 11 Slovenian hospitals in 2005 and 2006, 60 (34%), from eight hospitals, harbored genes for CTX-M enzymes, with bla(CTX-M-15) detected by sequencing. These 60 isolates comprised 11 pulsed-field gel electrophoresis-defined strains, with several clusters of closely related isolates. Plasmids encoding CTX-M-15 enzyme were highly transmissible.

Molecular epidemiology of catheter-related bloodstream infections caused by coagulase-negative staphylococci in haematological patients with neutropenia.

Catheter-related bloodstream infection (CRBSI) caused by coagulase-negative staphylococci (CNS) is common in haematological patients with febrile neutropenia. As the clinical signs of CRBSI are usually scarce and it is difficult to differentiate from blood culture contamination, we tried to confirm CRBSI by molecular typing of CNS isolated from paired blood cultures (one from a peripheral vein and another from the central venous catheter hub). Blood cultures were positive in 59 (36%) out of 163 patients. CNS were isolated in 24 (40%) patients; in 14 from paired blood cultures (28 isolates) and in 10 from a single blood culture. CNS from paired blood cultures were identified as Staphylococcus epidermidis. Antimicrobial susceptibility was determined and bacteria were typed by pulsed-field gel electrophoresis (PFGE) of bacterial genomic DNA. In 13 patients, the antibiotic susceptibility of isolates was identical. The PFGE patterns from paired blood cultures were identical or closely related in 10 patients, thus confirming the presence of CRBSI. In the remaining four patients they were unrelated, and suggested a mixed infection or contamination. Since CNS isolates from three patients had identical PFGE patterns, they were probably nosocomially spread amongst them.

Epidemiological typing of imipenem-resistant Pseudomonas aeruginosa.

The level of genetic heterogeneity of nine isolates of Pseudomonas aeruginosa resistant or intermediately susceptible to imipenem was determined by epidemiological typing using macrorestriction analysis of chromosomal DNA. The strains were isolated between December 2000 and February 2001 from a variety of specimens from nine patients hospitalized in five different departments of the University Medical Center in Ljubljana and in the nursing home. They belonged to seven genotypes or clones (A-G). Six isolates were heterogeneous, with different B-G genotypes. Three isolates had an identical A genotype but it is more likely that this genotype was more prone to develop imipenem resistance than to spread among the patients.

[Stenotrophomonas maltophilia as a cause of hospital infections--typing of clinical isolates using pulsed field gel electrophoresis] ]. / Stenotrophomonas maltophilia kao uzrocnik bolnickih infekcija--tipizacija klinickih izolata metodom elektroforeze u pulzirajucem polju (PFGE).

Stenotrophomonas maltophilia (S. maltophilia) has been recognised now as an important cause of hospital infections. As S. maltophilia is resistant to many antibiotics, attempts have been made to identify the sources of S. maltophilia infection and route of its transmission. From July till October 1998, 22 isolates of S. maltophilia were obtained from 20 patients hospitalised at eight different wards. Strain typing was performed by macrorestriction analysis of chromosomal DNA by use of PFGE (XbaI and SpeI enzymes, in a CHEF DR III drive module). PFGE analysis of 22 S. maltophilia isolates revealed 9 different types designated by letters A to I. The source and route of the spread of infection could not be identified. These results may indicate that we had clusters of S. maltophilia infection in cardiosurgery ward and ICU by types A, B, C and D; in neurosurgical ICU by type E and in urology ICU by type H.

Serotype, antimicrobial susceptibility and clone distribution of Pseudomonas aeruginosa in a university hospital.

To study the epidemiology of Pseudomonas (P.) aeruginosa, serotyping and antibiotic susceptibility testing were performed on 208 clinical isolates. Sixteen of these isolates were additionally examined by pulsed-field gel electrophoresis (PFGE) of chromosomal DNA. All 208 isolates belonged to 13 of the 16 described serotypes. Thirty isolates (14.4%) belonged to serotype O6, 75 (36%) to serotype O11 and 53 (25.6%) to other serotypes, 42 (20.2%) were polyagglutinating and eight (3.8%), autoagglutinating. Twenty-six per cent of isolates were resistant to piperacillin, 9.1% to ceftazidime, 9.6% to imipenem, 45.7% to ciprofloxacin, 39.9% to amikacin, 51% to gentamicin, 48.6% to netilmicin and 45.2% to tobramycin. Antibiotic resistance varied according to serotype and was highest in serotype O11. Sixteen isolates were analysed by PFGE; nine were multiresistant serotype O11 isolates recovered in four hospital units, while seven were susceptible serotype O6 or O11 isolates from a single unit. The multiresistant serotype O11 isolates had two PFGE patterns indicating that they were capable of spreading: one PFGE pattern was shared by the isolates recovered in spring and the other by those recovered in autumn 1997. The seven susceptible O6 and O11 isolates from a single unit had seven different PFGE patterns. Our results have shown that serotype O11 was the most prevalent P. aeruginosa serotype in our hospital and that its antibiotic resistance was high. The discriminatory power of serotyping is inadequate to permit the tracing of different strains. Macrorestriction analysis of chromosomal DNA was found to provide the best means of strain discrimination.