Multiresistant Acinetobacter baumannii isolates in intensive care units in Greece

One hundred and twenty-one clinical isolates of Acinetobacter baumannii recovered from the intensive care units (ICUs) of nine tertiary-care hospitals in Athens, Greece were studied in order to determine whether the increasing appearance of resistant acinetobacters is due to the spread of epidemic strains. The majority of the isolates exhibited resistance to ampicillin-sulbactam, and the most common antibiotic resistance profiles comprised resistance to nine and eight of the 11 potentially active antibiotics tested, respectively. Pulsed-field gel electrophoresis showed that 68% of the isolates, recovered from all ICUs, belonged to two clonal groups, indicating inter-hospital dissemination of multiresistant A. baumannii in our region.

Predominance of two M-types among erythromycin-resistant group A Streptococci from Greek children

In order to investigate the potential relationship between erythromycin resistance and specific M-serotypes among clinical isolates of Streptococcus pyogenes from children in Greece, we randomly selected a total of 49 erythromycin-resistant (EryR) and 21 erythromycin-susceptible (EryS) isolates from the 1158 S. pyogenes isolates from the two main children's hospitals of Athens during the period October 1997 to October 1998. The isolates were further characterized by M-serotyping, examined for their susceptibility to penicillin, vancomycin and clindamycin, and categorized into resistance phenotypes. A total of 248 (21%) S. pyogenes isolates in the two main children's hospitals of Athens during the study period were resistant to erythromycin. All 49 EryR and 21 EryS isolates were susceptible to penicillin and vancomycin. With respect to erythromycin and clindamycin resistance, phenotypes M and IR MLSB dominated, with 30 and 17 isolates, respectively, two isolates belonged to the CR MLSB phenotype. Among the erythromycin resistant isolates, two M serotypes were dominant: M22 (30%) and M84 (41%). More specifically, M22 and M84 were most prevalent in resistance phenotypes IR MLSB (65%) and M (63%), respectively. In the susceptible group, no isolate belonged to these two M-serotypes, nor was a predominant serotype found. In contrast to susceptible isolates, two distinct M-serotypes were highly represented among EryR S. pyogenes isolates and predominantly associated with two distinct phenotypes.

Extended-spectrum beta-lactamase types in Klebsiella pneumoniae and Escherichia coli in two Greek hospitals

Seventy-nine Klebsiella pneumoniae and 124 Escherichia coli clinical strains, isolated consecutively during August-October 2001 in two Greek hospitals, were examined for production of extended-spectrum beta-lactamases (ESBLs). Seventy-one (35%) isolates (46 K. pneumoniae and 25 E. coli) were ESBL-positive by phenotypic methods. Isoelectric focusing of beta-lactamases and PCR assays for bla genes showed that SHV-5-type ESBLs were the most frequent (45 isolates, 22%) followed by CTX-M (24 isolates, 12%) and IBC (three isolates, 1.5%). The latter two ESBL types may have been established recently in this setting.

Spread of integron-associated VIM-type metallo-beta-lactamase genes among imipenem-nonsusceptible Pseudomonas aeruginosa strains in Greek hospitals

Fifty-eight imipenem-nonsusceptible (MIC >or= 8 microg/ml) Pseudomonas aeruginosa strains isolated during May 2001 in 15 Greek hospitals were studied. Thirty-six isolates derived from nine hospitals carried VIM-type metallo-beta-lactamase genes, as found by PCR. In 34 isolates, bla(VIM) was associated with class 1 integrons of various sizes. DNA sequencing indicated the presence of bla(VIM-2) gene cassettes in a variety of integron structures. Random amplified polymorphic DNA typing suggested diversity of the bla(VIM)-positive strains. Synergy between 2-mercaptoacetic acid and imipenem indicated carbapenemase activity in 26 bla(VIM)-positive strains.

Resistance to beta-lactams among blood isolates of Salmonella spp. in European hospitals: results from the SENTRY Antimicrobial Surveillance Program 1997-98

The susceptibility to beta-lactams and the beta-lactamase content of 110 Salmonella spp. blood isolates collected during 1997-98 in 19 European centers participating in the SENTRY Surveillance Program were studied. Thirty-one isolates (28%) were resistant to penicillins, due to production of TEM-1 (27 isolates), OXA-1 (three isolates) or TEM-1 + OXA-1 (one isolate). All OXA-1 producers and 10 TEM-1-producing isolates were also resistant to penicillin-clavulanic acid combinations. In the latter isolates, this phenotype was associated with increased production of TEM-1. Sixteen TEM-1-producing Salmonella Enteritidis isolates and one OXA-1-producing S. Typhimurium isolate were able to transfer beta-lactam resistance by conjugation.

CTX-m-3 beta-lactamase-producing Escherichia coli from Greece

An Escherichia coli clinical strain resistant to all beta-lactams except carbapenems was isolated in a Greek hospital. Analysis of beta-lactamase content by isoelectric focusing, PCR assays specific for various bla genes, and DNA sequencing showed that the strain produced TEM-1, a Citrobacter freundii AmpC-related cephalosporinase, and CTX-M-3. The blaCTX.M-3 gene was carried by a 120-kb plasmid that was readily transferable to a susceptible E. coli host.

Evaluation of an anti-PBP 2a slide latex agglutination test in coagulase-negative staphylococci isolated in Greek hospitals

Oxacillin resistance was examined in 258 coagulase-negative staphylococci from Greek hospitals. mecA DNA was detected in 168 isolates, which were also resistant to oxacillin by agar dilution and disk diffusion, according to the current NCCLS breakpoints. Both methods exhibited a relatively low specificity misclassifying 21 and 19 of the 90 mecA-negative isolates respectively as oxacillin resistant. In contrast, an anti-PBP 2a latex agglutination test, applied after induction by oxacillin, correctly classified 163 mecA-positive (sensitivity 97%) and 88 mecA-negative isolates (specificity 97.7%).

Identification of Malassezia species from patient skin scales by PCR-RFLP

OBJECTIVE

This study was aimed at the development of a DNA-based procedure directly applicable to pathological skin scales and at the assessment of its value in rapid laboratory confirmation and identification of each of the seven Malassezia species. These lipophilic basidiomycetous yeasts in predisposed individuals are involved in pityriasis versicolor, seborrheic dermatitis, blepharitis, folliculitis, atopic dermatitis and fungemia. Standard identification procedures to species level are available, but so far no system for direct detection and characterization of Malassezia species in clinical specimens is available.

METHODS

Malassezia DNA was extracted from pathological skin scales by a modified hexadecyltrimethylammonium bromide (CTAB) method and amplified by single and nested polymerase chain reaction (PCR), assays using the general fungal ITS 1/4 and 3/4 primers for amplification of sequences from the Malassezia major ribosomal DNA complex. Restriction fragment length polymorphism (RFLP) analysis of PCR products was used in subsequent species identification. DNA extracted from culture-positive skin scales was also tested by PCR and the RFLP patterns obtained were analyzed.

RESULTS

A total of 36 isolates were tested. Distinct pure culture and skin-scale ITS 3/4 HinfI and AluI restriction patterns differentially identified M. furfur, M. globosa, M. restricta, M. sympodialis, M. pachydermatis, M. obtusa and M. slooffiae. Malassezia DNA was extracted from pathological skin scales and RFLP identified solitary and multiple Malassezia species in the same specimen. Molecular identification was confirmed by cultures and biochemical tests. Concurrent detection and identification of Candida and Yarrowia species was also feasible from skin scales.

CONCLUSION

The proposed method, described for the first time, could provide a sensitive and rapid detection and identification system for Malassezia species, which may be applied to epidemiological surveys and routine practice.

Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a neonatal intensive care unit in the high-prevalence area of Athens, Greece

Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (EPKP) strains are frequently implicated in outbreaks in neonatal intensive care units (NICUs). During the period from 1997 to 1998, 21 infections and 23 colonizations with EPKP were recorded in the NICU of a children's hospital in Athens, Greece. Seventeen of the infected and 12 of the colonized neonates had been referred from other hospitals. The remaining infections and colonizations occurred during the current hospitalization. Pulsed-field gel electrophoresis typing showed that the latter cases were due to an outbreak strain that persisted in the unit, while the repeated introduction of EPKP carriers was mostly due to clonal outbreaks in two maternity hospitals.

First report of Cryptococcus neoformans var. gattii serotype B from Greece

A plethora of cases of Cryptococcus neoformans infections have been recorded worldwide in immunocompromised individuals. The number of such cases showed a steady rise before 1981 and increased dramatically thereafter due to the AIDS epidemic. A similar pattern has been seen in Greece but, so far, infections appear to have been caused by C. neoformans var. neoformans. This paper describes for the first time two culture-proven C. n. var. gattii serotype B infections in Greece, one in an AIDS patient and one in a patient with systemic lupus erythematosus.

Prospective use of RFLP analysis on amplified Cryptococcus neoformans URA5 gene sequences for rapid identification of varieties and serotypes in clinical samples

Clinical isolates of Cryptococcus neoformans, whole blood, cerebrospinal fluid, bronchoalveolar lavage fluid from patients with positive cryptococcal antigen latex-agglutination test, and spiked clinical material from healthy individuals, were tested by polymerase chain reaction (PCR) with primers amplifying C. neoformans URA5 gene sequences. To test compatibility of different DNA extraction protocols with the PCR-restriction fragment length polymorphism (RFLP) assay, a commercial DNA extraction kit (XTRAX; Gull Laboratories, UT, USA) was used alongside with the hexadecyltrimethylammonium bromide (CTAB) method on spiked biological fluids. Both methods extracted DNA from spiked clinical samples containing C. neoformans (8 +/- 2 cells ml(-1)) and generated amplification products suitable for restriction enzyme analysis. Alu I digestion differentiated the two varieties of C. neoformans. Three distinct RFLP patterns were obtained upon restriction with MspI corresponding to serotypes A, AD and B, C and D. URA5 PCR followed by RFLP analysis, coupled with a sensitive in-house or commercially available DNA extraction method from clinical samples, could be successfully incorporated into rapid routine diagnostic strategies. It could also provide an expeditious tool for epidemiology-based population genetics studies.

Oral pseudomembranous candidiasis, herpes simplex virus-1 infection, and oral mucositis in head and neck cancer patients receiving radiotherapy and granulocyte-macrophage colony-stimulating factor (GM-CSF) mouthwash

Oral pseudomembranous candidiasis (OPC) was evaluated in 61 patients receiving head and neck radiotherapy (RT). Herpes simplex virus-1 (HSV-1) reactivation was also investigated in 14 patients. According to the agreed protocol, granulocyte-macrophage colony-stimulating factor (GM-CSF) mouthwash was administered in 46 patients with radiation-induced ulcers. Candidiasis was diagnosed in 31 patients. Candida albicans was the most frequent isolate. Multiple Candida species were isolated from the lesions of four patients. Concurrent candidiasis and radiation-induced ulcers were observed in 17 patients. Viral culture and the polymerase chain reaction disclosed the presence of HSV-1 in five patients. Twenty of the 46 patients, with initial mucositis grade II and grade III, completed RT with mucositis grade I, indicating a beneficial effect of GMCSF mouthwash, although further controlled studies are necessary to verify that. In conclusion, OPC was an important infection in patients undergoing radiotherapy. The role of HSV-1 in oral mucositis during head and neck radiotherapy needs additional study.

Subtyping and antifungal susceptibilities of Candida spp. in the intensive care unit of a Greek general hospital

This study identified the Candida spp., susceptibility to antifungal agents and the prevailing Candida albicans subtypes responsible for infections or colonization of 42 patients in the ICU over a 6-month period. Most isolates were C. albicans (66.1%) and Candida tropicalis (28.3%) all of which were susceptible in vitro to antifungal agents. Subtypes of the C. albicans isolates were identified by pulsed field gel electrophoresis Sfi I chromosomal digests. Two major C. albicans subtypes were identified, whereas subtype heterogeneity was found among strains of Candida glabrata and C. tropicalis. Sfi I PFGE restriction patterns were able to discriminate between sub-populations of C. albicans isolates, clustering them into distinct, epidemiologically congruous groups.

Serum is the preferred clinical specimen for diagnosis of human brucellosis by PCR

Human brucellosis poses a significant public health problem in many developing countries and requires fast and accurate diagnosis. A PCR assay amplifying part of the 31-kDa Brucella abortus antigenic protein gene sequence was developed and applied to whole-blood and serum samples from 31 brucellosis patients and 45 healthy individuals. All patients except one had detectable Brucella DNA in either whole blood or serum (combined sensitivity, 97%), but the assay sensitivity was higher with serum samples (94%) than with whole-blood samples (61%). The assay specificity was excellent (100%). A confirmatory PCR assay targeting another Brucella gene region (omp-2) was also developed but lacked sensitivity. Serum is the optimal specimen for the diagnosis of brucellosis by PCR, a choice that leads to assay simplification and shortens turnaround time.

Antibiotic resistance rates and macrolide resistance phenotypes of viridans group streptococci from the oropharynx of healthy Greek children

A total of 200 isolates of viridans group streptococci isolated from the oropharynx of healthy Greek children were studied. Vancomycin, rifampicin, fluoroquinolones and dalfopristin/quinupristin were active against all tested isolates. High level resistance to gentamicin was not seen. Intermediate and high-level penicillin resistance was present in 28.5 and 14.5% isolates, respectively, with 41.3% of the latter group, being also resistant to cefotaxime. Resistance rates to other antimicrobials were as follows - erythromycin 38.5%, clarithromycin 33.5%, clindamycin 7.5% and tetracycline 23%. Penicillin resistance occurred more frequently in Streptococcus mitis isolates, while macrolide resistance was more frequent in S. oralis. MLSB resistance phenotype M was dominant (74%) among erythromycin resistant isolates, with phenotypes IR and CR being represented by 6 and 20% of isolates, respectively.

Multicenter evaluation of epidemiological typing of methicillin-resistant Staphylococcus aureus strains by repetitive-element PCR analysis. The European Study Group on Epidemiological Markers of the ESCMID

Rapid and efficient epidemiologic typing systems would be useful to monitor transmission of methicillin-resistant Staphylococcus aureus (MRSA) at both local and interregional levels. To evaluate the intralaboratory performance and interlaboratory reproducibility of three recently developed repeat-element PCR (rep-PCR) methods for the typing of MRSA, 50 MRSA strains characterized by pulsed-field gel electrophoresis (PFGE) (SmaI) analysis and epidemiological data were blindly typed by inter-IS256, 16S-23S ribosomal DNA (rDNA), and MP3 PCR in 12 laboratories in eight countries using standard reagents and protocols. Performance of typing was defined by reproducibility (R), discriminatory power (D), and agreement with PFGE analysis. Interlaboratory reproducibility of pattern and type classification was assessed visually and using gel analysis software. Each typing method showed a different performance level in each center. In the center performing best with each method, inter-IS256 PCR typing achieved R = 100% and D = 100%; 16S-23S rDNA PCR, R = 100% and D = 82%; and MP3 PCR, R = 80% and D = 83%. Concordance between rep-PCR type and PFGE type ranged by center: 70 to 90% for inter-IS256 PCR, 44 to 57% for 16S-23S rDNA PCR, and 53 to 54% for MP3 PCR analysis. In conclusion, the performance of inter-IS256 PCR typing was similar to that of PFGE analysis in some but not all centers, whereas other rep-PCR protocols showed lower discrimination and intralaboratory reproducibility. None of these assays, however, was sufficiently reproducible for interlaboratory exchange of data.

Comparison of Mycobacterium avium isolates from Greek AIDS and human immunodeficiency virus-negative patients by pulsed-field gel electrophoresis

OBJECTIVE

To compare the chromosomal types of Mycobacterium avium strains infecting HIV-negative and AIDS patients in Greece.

METHODS

In total, 41 Mycobacterium avium isolates, 23 from AIDS and 18 from HIV-negative patients, were compared by pulsed-field gel electrophoresis of genomic DNA after XbaI digestion. The majority (87%) of AIDS isolates were from disseminated infection, while the majority (61%) of HIV-negative isolates were from children with cervical lymphadenitis.

RESULTS

Pulsed-field gel electrophoresis classified strains whose electrophoretic patterns were at least 85% similar into three clusters, A (four isolates), B (12 isolates), and C (15), while 10 isolates remained outside of these clusters. There was no statistically significant correlation of any PFGE cluster with a specific patient group. Within each patient group, no significant correlation of PFGE type with time, place of residence or, in the case of AIDS patients, hospital attended was observed.

CONCLUSIONS

Genotypic similarities between isolates responsible for disseminated infection in AIDS patients and lymphadenitis in HIV-negative children suggest that related strains, possibly from an environmental source, cause both types of infections.

Prevalent mechanisms of resistance among common enterobacterial isolates in Greek hospitals

The recent data concerning antibiotic resistance of the enterobacteria isolated in Greek hospitals are reviewed. A variety of mechanisms of resistance, clustered in most of the cases, was observed. Epidemics of plasmids were responsible for dissemination of third-generation cephalosporins, aminoglycosides, and trimethoprim resistance among Klebsiella pneumoniae and, to a lesser extent, Escherichia coli isolates. Stable depression of the expression of chromosomal cephalosporinase is the main cause of resistance to third-generation cephalosporins observed at high frequencies in Enterobacter spp. strains.