Sabine Lauwers

Occurrence of multiple genomovars of Burkholderia cepacia in cystic fibrosis patients and proposal of Burkholderia multivorans sp. nov.

We performed an integrated genotypic and phenotypic analysis of 128 strains of the genera Burkholderia, Ralstonia, and Pseudomonas in order to study the taxonomic structure of Burkholderia cepacia and its relationships with other Burkholderia species. Our data show that presumed B. cepacia strains isolated from cystic fibrosis patients belong to at least five distinct genomic species, one of which was identified as Burkholderia vietnamiensis. This group of five phenotypically similar species is referred to as the B. cepacia complex. The name Burkholderia multivorans is proposed for one of these genomic species, which was formerly referred to as B. cepacia genomovar II; the remaining B. cepacia groups are referred to as genomovars I, III, and IV, pending additional differential phenotypic tests. The role and pathogenic potential of each of these taxa, particularly in view of the potentially fatal infections in cystic fibrosis patients, need further evaluation. The data presented also demonstrate that Pseudomonas glathei and Pseudomonas pyrrocinia should be reclassified as Burkholderia species.

Third Belgian multicentre survey of antibiotic susceptibility of anaerobic bacteria.

OBJECTIVES To collect recent data on the susceptibility of anaerobes and to compare them with results from previous studies. METHODS Four hundred and forty-three anaerobic clinical isolates from various body sites were prospectively collected from October 2003 to February 2005 in nine Belgian hospitals. MICs were determined for nine anti-anaerobic and three recently developed antibiotics. RESULTS Most gram-negative bacilli except Fusobacterium spp. were resistant to penicillin. Piperacillin/tazobactam, metronidazole, chloramphenicol, meropenem and amoxicillin/clavulanic acid were very active against all groups, but only 86% of Bacteroides fragilis group strains were susceptible to the latter. Cefoxitin, cefotetan and clindamycin were less active. In particular, only 62%, 52% and 48% of B. fragilis group strains were susceptible, respectively. Clindamycin shows a continuing decrease in activity, as 83% were still susceptible in 1987 and 66% in 1993-94. Anti-anaerobic activity of the new antibiotics is interesting, with MIC50 and MIC90 of 1 and >32 mg/L for moxifloxacin, 2 and 4 mg/L for linezolid and 0.5 and 8 mg/L for tigecycline. CONCLUSIONS The susceptibility of anaerobic bacteria remains stable in Belgium, except for clindamycin, which shows a continuous decrease in activity. However, for each of the tested antibiotics, at least a few resistant organisms were detected. Consequently, for severe infections involving anaerobic bacteria, it could be advisable to perform microbiological testing instead of relying on known susceptibility profiles. Periodically monitoring background susceptibility remains necessary to guide empirical therapy.

Isolation of Arcobacter skirrowii from a Patient with Chronic Diarrhea

The genus Arcobacter currently includes four species ([7][1]). Two species, Arcobacter cryaerophilus and Arcobacter butzleri , have been associated with human disease. They were mainly isolated from patients with diarrhea and bacteremia ([2][2], [3][3], [6][4]). Arcobacter nitrofigilis has been

The national prevalence survey of nosocomial infections in Belgium, 1984

A national one-day prevalence survey of nosocomial infections was carried out in March 1984 in 106 Belgian acute-care hospitals involving 8723 patients of whom 6130 had undergone surgery. Three infections were studied: surgical wound infection, bacteraemia and urinary-tract infection. One or more of these three infections was recorded in 9.3% of all patients and in 11.8% of surgical patients. Prevalences increased with increasing duration of hospital stay and with higher ages, but the association of HAI with age was no longer significant after correction for duration of hospital stay. Prevalences varied considerably in different specialties. After adjustment for age and duration of stay, there was no association between perioperative antibiotic prophylaxis and the prevalence of the infections studied, but bias due to selection of higher risk patients in the antibiotic group was probable. Larger hospitals had a higher overall prevalence, but populations differed according to the size of the hospital. Bacteraemia was strongly associated with the presence of an intravenous catheter, and urinary-tract infection with a urinary catheter.

Neonatal infections with Pseudomonas aeruginosa associated with a water-bath used to thaw fresh frozen plasma

In our 15-bed neonatal intensive care unit (NICU), four new-borns were found to be colonized or infected with Pseudomonas aeruginosa within a period of one week. To identify the outbreak source, three independent studies were performed: epidemiological investigation, environmental surveillance and genotypic typing of isolates. Although epidemiological investigation by a case-control study revealed no conclusive results, the transfusion of fresh frozen plasma (FFP) and human albumin (HA) appeared to be the factor with highest risk. Environmental surveillance and random amplification of polymorphic DNA (RAPD) of isolates identified a water-bath used to warm FFP and HA as the likely reservoir for the outbreak. Further spread of the organism did not occur after elimination of this water-bath from the NICU. RAPD identified in addition an isolate from an infant hospitalized in the NICU five months before the outbreak with a pattern matching the one of the outbreak cluster.

Isolation of HIV-1 RNA from plasma: evaluation of eight different extraction methods.

The efficacy of eight different methods for the extraction of HIV-1 RNA from plasma was compared. The RNA preparation method that gave the best results by RT-PCR was the one described by Chomczynski and Sacchi (1987, Anal. Biochem. 162, 156-159). This method consists of a guanidine thiocyanate treatment followed by three phenol-chloroform-isoamylalcohol extractions and an ethanol precipitation. The disadvantage of this method is that it is time consuming and less suitable for the extraction of large series of samples. Moreover, due to the large number of procedural steps, there is a greater risk of sample mix-up or contamination. Of the single-step RNA purification methods, good results were obtained with the TRIzol method (Gibco Life Technologies, Paisley, UK) and with the extraction method offered by the NASBA kit (Organon Teknika, Turnhout, Belgium). The above single-step methods are recommended since both are sensitive enough to detect low copy numbers of HIV-RNA in the plasma of asymptomatic patients, and require only 2 h for completion. For most of the methods evaluated the inter-test variability was acceptable (mean variation coefficient between duplicate extraction varied between 17.3 and 47.3%). Inter-laboratory reproducibility was evaluated only for the TRIzol-method and found to be low (mean variation coefficient 63.4).

Recovery of microorganisms in semen and relationship to semen evaluation

Semen samples from 120 consecutive unselected men attending our fertility clinic were studied to determine the bacterial isolation rate of semen and its influence on semen quality. Each sample was cultured aerobically, anaerobically, and for Ureaplasma urealyticum and Mycoplasma hominis. The following were analyzed for each semen specimen: motility, morphologic features, and number of sperm cells and viscosity of the ejaculate. Four of the 120 samples had negative results; 101 cultures yielded one or more aerobic organisms (the majority with less than 20,000 microorganisms/ml); 26 yielded anaerobic organisms; and 40 yielded U. urealyticum. No single aerobic or anaerobic organism could be related to abnormal semen samples. Only the presence of U. urealyticum correlated significantly with abnormal semen samples (P less than 0.005). The most affected parameters were the number of spermatozoa (P less than 0.005) and motility (P less than 0.05). We conclude that routine aerobic and anaerobic bacterial cultures of semen are not useful in the clinical evaluation of male infertility. The usefulness of routine screenings for U. urealyticum must be investigated further.

In vitro susceptibility of Enterococcus faecium isolated from food to growth-promoting and therapeutic antibiotics.

A total of 76 E. faecium strains, isolated at retail level from raw poultry meat, cheese, raw pork, and preparations of cheese and raw pork, were tested for their susceptibility and resistance to growth-promoting antibacterials used in animals and antibiotics used therapeutically in humans. All strains were uniformly susceptible to the growth promoters bambermycin and avilamycin. Resistance against bacitracin, virginiamycin and narasin was high among strains from poultry meat. With tylosin, a macrolide antibiotic used therapeutically and for growth promotion, resistance was mainly detected in strains originating from poultry meat, though also in some strains from pork and from pork and cheese preparations. The therapeutic antibiotic dalfopristin/quinupristin did not show full cross-resistance with the growth-promoting antibiotic virginiamycin. With dalfopristin/quinupristin two different levels of resistance were found. Only one E. faecium strain isolated from poultry was resistant to the glycopeptides avoparcin and vancomycin. Only one poultry meat strain was highly resistant to ampicillin. However, nearly all poultry meat strains showed decreased sensitivity. Only 3 out of 24 poultry strains were susceptible to minocycline, while all strains from other origins were susceptible to this tetracycline antibiotic. High-level streptomycin resistance was seen in strains of all origins, though infrequently. High-level gentamicin resistance was not found.

Epidemiology and Pathogenesis of Ureaplasma Urealyticum in Spontaneous Abortion and Early Preterm Labor

The role of U. urealyticum in spontaneous and recurrent spontaneous abortion was studied in 633 women. Cervical colonization with U. urealyticum was found in 42.6% of 310 normal pregnant women, in 41.6% of 84 patients who underwent induced abortion, in 41.5% of 41 normal fertile patients, in 53.3% of 122 patients with spontaneous abortion and in 64.5% of 76 patients with recurrent spontaneous abortion. The cervical isolation rate was significantly higher in patients with spontaneous abortion (p<0.05) and recurrent spontaneous abortion (p<0.005) than in normal pregnant women. Endometrial colonization was more frequent in patients with recurrent spontaneous abortion (27.6%) than in normal fertile women (9.7%) (p<0.05). Moreover, in 6 patients with intact membranes and uncontrollable preterm labor resulting in fetal loss (all between the 20th and 28th week of gestation) U. urealyticum was isolated in 5 of them from the cervix, in 4 patients from the placenta and in 2 out of 4 from the amniotic fluid. Histological examination of the placenta showed signs of chorioamnionitis in 5 patients. From this study we conclude that although U. urealyticum is a common inhabitant of the lower genital tract, it may play a role in the etiology of spontaneous abortion and uncontrollable preterm labor.

In vitro antimicrobial activity of six medicinal plants traditionally used for the treatment of dysentery and diarrhoea in Democratic Republic of Congo (DRC)

Twenty-four crude extracts derived from six medicinal plants highly valued as antidiarrhoeal agents in Congolese folk medicine were screened for antimicrobial activity against several enteric pathogens. The results of this study indicated that the methanolic and aqueous extracts derived from three of them (Roureopsis obliquifoliolata, Epinetrum villosum and Cissus rubiginosa) possessed prominent antibacterial activity, therefore supporting the ethnomedical uses of these species. In addition, phytochemical analysis of these medicinal plants showed that 1/6 plant sample contained alkaloids, 6/6 triterpenes and/or sterols, 4/6 flavonoids, 3/6 tannins and 5/6 saponins. Anthraquinones were not detected in any of these plants.