Cécile Meex

Direct identification of bacteria from BacT/ALERT anaerobic positive blood cultures by MALDI-TOF MS: MALDI Sepsityper kit versus an in-house saponin method for bacterial extraction

In cases of bacteraemia, a rapid species identification of the causal agent directly from positive blood culture broths could assist clinicians in the timely targeting of empirical antimicrobial therapy. For this purpose, we evaluated the direct identification of micro-organisms from BacT/ALERT (bioMérieux) anaerobic positive blood cultures without charcoal using the Microflex matrix-assisted laser desorption/ionization (MALDI) time of flight MS (Bruker), after bacterial extraction by using two different methods: the MALDI Sepsityper kit (Bruker) and an in-house saponin lysis method. Brukers recommended criteria for identification were expanded in this study, with acceptance of the species identification when the first three results with the best matches with the MALDI Biotyper database were identical, whatever the scores were. In total, 107 monobacterial cultures and six polymicrobial cultures from 77 different patients were included in this study. Among monomicrobial cultures, we identified up to the species level 67 and 66 % of bacteria with the MALDI Sepsityper kit and the saponin method, respectively. There was no significant difference between the two extraction methods. The direct species identification was particularly inconclusive for Gram-positive bacteria, as only 58 and 52 % of them were identified to the species level with the MALDI Sepsityper kit and the saponin method, respectively. Results for Gram-negative bacilli were better, with 82.5 and 90 % of correct identification to the species level with the MALDI Sepsityper kit and the saponin method, respectively. No misidentifications were given by the direct procedures when compared with identifications provided by the conventional method. Concerning the six polymicrobial blood cultures, whatever the extraction method used, a correct direct identification was only provided for one of the isolated bacteria on solid medium in all cases. The analysis of the time-to-result demonstrated a reduction in the turnaround time for identification ranging from 1 h 06 min to 24 h 44 min, when performing the blood culture direct identification in comparison with the conventional method, whatever the extraction method.

Proportion of extended-spectrum ß-lactamase-producing Enterobacteriaceae in community setting in Ngaoundere, Cameroon

AbstractBackgroundThere is no information regarding the resistance mechanisms of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae in community setting in Cameroon. The current study aimed to determine the proportion of ESBLs in Enterobacteriaceae isolated in the community and to analyse some risk factors associated with ESBL carriage.MethodsFaecal samples were collected from 208 different outpatients and 150 healthy student volunteers between 3 January and 3 April 2009. Enterobacterial isolates resistant to third-generation cephalosporins were screened for ESBL production by the double-disk synergy test. Presumptive ESBL-producing isolates with positive synergy test were identified by Mass Spectrometry using the BioTyper MALDI-TOF. For such ESBL positive isolates, antibiotic susceptibility was determined by the Vitek 2 system. PCR and sequencing were performed for the detection of different types of ESBL genes in presumptive ESBL-producing isolates. Statistical methods were used for the univariate calculation of risk factors.ResultsDuring the study period, a total of 358 faecal samples were analysed; 58 of such samples (16%) showed an ESBL phenotype and were confirmed by PCR. The proportion of ESBL producers in faecal carriage was statistically different between outpatients and student volunteers (23.1% vs. 6.7%: p < 0.000). According to a univariate analysis, previous use of antibiotics (ciprofloxacin) appeared to be a risk factor for ESBL carriage (p < 0.05). Escherichia coli was the species most frequently isolated among the ESBL producers in outpatients (66.7%) and student volunteers (90%). Isolates showed additional resistance to gentamicin, ciprofloxacin and trimethoprim/sulfamethoxazole but none of them was resistant to temocillin, amikacin or meropenem. Most of the strains (97%) produced a CTX-M group 1 enzymes [CTX-M-15 (98%) or CTX-M-1 (2%)] and the remaining strains produced SHV-12 enzyme (3%).ConclusionsThe use of drugs such as amoxicillin, ciprofloxacin and trimethoprim/sulfamethoxazole does not seem appropriate for empirical treatment because of emerging resistance. The implementation in Cameroon or in other African countries of methods of screening ESBL-producing organisms in routine laboratories is of great importance in order for us to offer patients appropriate treatment and for infection control efforts to succeed.

Fatal Alveolar Echinococcosis of the Lumbar Spine

ABSTRACT For the last 10 years, the southern part of Belgium has been recognized as a low-risk area of endemicity for alveolar echinococcosis. This infection, caused by Echinococcus multilocularis, usually induces a severe liver condition and can sometimes spread to other organs. However, alveolar echinococcosis involving bones has been described only very rarely. Here, a fatal case of spondylodiscitis due to E. multilocularis contracted in southern Belgium is reported.

Acute cholecystitis with Listeria monocytogenes

Abstract Listeriosis, an opportunistic food-borne disease caused by Listeria monocytogenes, is infrequent and occurs preferentially in patients at the extremes of age, during pregnancy or in immunocompromised hosts. Most common manifestations are maternofoetal and neonatal infections, severe invasive presentations such as bacteraemia with or without central nervous system symptoms occuring preferentially in immunosuppressed patients and self-limited gastro-enteritis affecting healthy individuals. Exceptionally, focal infections such as cholecystitis are described. We report here a case of acute cholecystitis caused by Listeria monocytogenes in an 82-year-old woman. Thanks to a successful treatment: cholecystectomy and antimicrobial therapy (amoxicillin plus clavulanic acid), the patient soon recovered. This case-report provides an opportunity to review the current literature concerning the association of Listeria monocytogenes and cholecystitis.

DNA fingerprinting using Diversilab system for genotyping characterization of Microsporum audouinii and Trichophyton violaceum

Poster sessions: All poster boards are situated on the exhibition floor of the congress centre. The poster exhibition is open to all participants during the entire congress. The numbers on the poster boards correspond with the abstract numbers in this abstract supplement. All authors of odd poster numbers must be present at their poster on Saturday 12 October, from 11:00 to 12:00 hours. All authors of even poster numbers must be present at their poster on Sunday 13 October, from 11:00 to 12:00 hours. All posters are indicated by the prefix: P.

P1869 Evaluation of a new commercial real-time PCR for the de-tection of Aspergillus spp. in serum and respiratory samples

1. Ascioglu S. et coll. 2002.Defining opportunistic invasive fungal infections in immunocompromised patients with cancer and hematopoietic stem cell transplants: an international consensus. Clin. lnfect. dis.34:7-14. 2. Yamakami Y. A. Hashimoto, I. Tokymatsu and M. Nasu. 1996. PCR detection for Aspergillus species in serum of patients with nvasive aspergillosis. J. Clin. Microbiol. 36:3619-3623. Objectives. Diagnosis of invasive aspergillosis is still disappointing and often delayed because of the lack of sensitivity of diagnostic tools. DNA detection based-methods have been developed, but differ widely and comparisons are difficult to assess. The objective of the study is to compare a new commercial real-time PCR kit, affigene® Aspergillus tracer assay, with an in house nested PCR targeting 18S rRNA Aspergillus sp. gene. Methods. Twelve patients at risk for invasive aspergillosis were included in the study. They were classified to have possible (5 cases), probable (1 case) or proven (6 cases) invasive aspergillosis following E.O.R.T.C. criteria. Fifteen serum and respiratory paired samples were collected. The DNA extraction was performed by using the QIAmp DNA mini kit® (Qiagen, Germany). All samples were tested by both PCR assays and respiratory samples were cultured. Results. Respiratory samples. A. fumigatus, A. niger and A. flavus were isolated from 10/15 samples; both PCR methods were positive for these samples except one that was positive for affigene® and equivocal for the nested PCR. The real-time PCR assay reported cycle thresholds ranging from 25 to 38. Three of the five culture-negative samples were negative by both PCR methods; one of three was negative in affigene® assay and equivocal by nested PCR; the last sample was positive in affigene® assay and negative by nested PCR. Serum. Thirteen of fifteen blood samples were negative by both PCR methods. One sample was equivocal by nested PCR and was inhibited in affigene® assay despite a culture-positive paired respiratory sample. The last case was inhibited by the real-time PCR assay and negative by nested PCR. Nor the nested PCR, nor affigene® assay could detect any Aspergillus DNA in serum. In total, there was 87% of agreement between the two PCR assays. Conclusion. Both methods are in good agreement and can detect at least three different species of Aspergillus. However, the sensitivity of both assays does not permit the detection of Aspergillus DNA in serum. affigene® assay can easy replace the “in house” assay: it allows a fast and standardized detection of Aspergillus sp. DNA in respiratory samples without inconvenient due to the handling of PCR products.