Biomedical subjects
Publications and source records attributed to J Verhaegen.
The majority of human Rhodococcus equi infections occur in immunocompromised hosts, especially those with AIDS, and infection in immunocompetent patients is rare. Reported here is a case of R. equi infection in a seemingly healthy patient with a very complicated course. Despite neurosurgery and prolonged antibiotic therapy the patient deceased.
Four separate categories of chronic Pseudomonas aeruginosa (Pa) infection in children with cystic fibrosis (CF) have been previously defined, based on airway cultures taken over the previous year. The aim of the present study was to evaluate this definition in the current authors' paediatric and adult CF clinic using clinical, immunological and lung function parameters. During follow-up, out of 193 patients, 55 (34%) CF patients had never been infected with Pa, 27 (17%) were free of Pa, 29 (18%) were intermittently infected and 51 (31%) were chronically infected. Disease severity markers, such as lung function, were significantly worse in the chronic group, especially in the paediatric population. Differences in adult patients were smaller and no longer significant. Pa antibodies differed strongly between the groups, and were very high (mean+/-sd 55.4+/-5.5) and highly statistically significant from all other groups in the chronic group. They were low and different from all other groups in the never group (1.8+/-0.6). Pa antibodies did not differ between the free of Pa and the intermittent group. In conclusion, the current authors confirmed an agreement between Pseudomonas aeruginosa status according to the new definition and clinical status, as well as with the level of Pseudomonas aeruginosa antibodies.
Described here are three cases of acute native valve endocarditis due to the coagulase-negative pathogen Staphylococcus lugdunensis with serious complications. Two of the three patients died despite optimal antibiotic therapy and cardiovascular surgery. These cases demonstrate the aggressive nature of S. lugdunensis and emphasize the importance of identifying coagulase-negative staphylococci to the species level and not considering the isolation of S. lugdunensis from normally sterile body fluids as contamination. On the contrary, when this organism is found in patients with endocarditis, early surgery should be considered. The possibility that this organism could be misidentified as S. aureus because of "autocoagulation" and that commercial identification systems may misidentify it as S. haemolyticus, S. hominis or S. warneri should also be remembered.
This study analyses consumption patterns of fluoroquinolones in treating respiratory tract infections in ambulatory care in Belgium and describes susceptibility of Streptococcus pneumoniae isolates to fluoroquinolones. Consumption data were obtained from IMS Health. Pneumococcal resistance was investigated in 600 blood isolates collected from 1998 to 2003. Although consumption of fluoroquinolones has increased rapidly over the last decade, this trend does not seem to persist more recently. Fluoroquinolones were mainly used to treat urinary and lower respiratory tract infections, but rarely in the management of upper respiratory tract infections. The use of new fluoroquinolones (levofloxacin, moxifloxacin) and the ongoing use of older fluoroquinolones have not led to increased pneumococcal resistance, which remained below 1% for levofloxacin and was 0% for moxifloxacin.
We report a case of cryptococcal meningitis in an immunocompetent female patient with exposure to a pet magpie (Pica pica). Genetically indistinguishable isolates were cultured from the cerebrospinal fluid of the patient and excreta of the bird. Our data strongly suggest zoonotic transmission of Cryptococcus neoformans var. grubii from a magpie to this patient.
Of 233 erythromycin-resistant pneumococcal isolates collected in Belgium in 1999-2000, 89.7% carried the erm(B) gene, 6% the mef(A) gene, and 3.5%erm(B) plus mef(A). Two isolates contained neither erm(B) nor mef(A); one contained an erm(A) subclass erm(TR) gene, while the other contained an A2058G mutation in domain V of the 23S rRNA gene. Of 209 erm(B)-positive isolates, 191 had clindamycin MICs > 16 mg/L and 18 had MICs < or = 16 mg/L. Mef(A)-positive isolates all displayed the M resistance phenotype. Telithromycin remained active against erythromycin-resistant isolates, with the highest telithromycin MIC50 being found in mef(A)-positive isolates. No difference in the prevalence of different resistance mechanisms was observed compared to isolates collected in 1995-1997.
Nasopharyngeal carriage is a major factor in the transmission of pneumococcal disease. The aim of this study was to determine the prevalence of asymptomatic nasopharyngeal carriage of Streptococcus pneumoniae and the distribution of serogroups and serotypes in children aged 3-36 months attending day care centres in Belgium. A single nasopharyngeal swab was cultured from 467 children attending 30 different day care centres between December 2000 and March 2001. S. pneumoniae isolates were serotyped and their antibiotic susceptibilities assessed by disk diffusion. The overall nasopharyngeal carriage rate for S. pneumoniae was 21% in the 467 children. None of the commonly accepted risk factors studied was associated significantly with carriage. Capsular serotypes isolated were 19F (27.3%), 6B (20.2%), 23F (19.2%), 19A (10.1%), 6A (7.1%), 14 (5.1%) and others (11.0%). Theoretical coverage by the seven-valent (serotypes 4, 6B, 9V, 14, 18C, 19F and 23F) pneumococcal conjugate vaccine was 73.7%. Fourteen (14.1%) of 99 strains were non-susceptible to penicillin, 48 (48.5%) to tetracycline and 61 (61.6%) to erythromycin. Theoretical coverage by the seven-valent pneumococcal conjugate vaccine was 93% for the penicillin-resistant serotypes, 69% for the tetracycline-resistant serotypes and 75% for the erythromycin-resistant serotypes. Use of the seven-valent pneumococcal conjugate vaccine could potentially reduce nasopharyngeal carriage of the antibiotic-resistant strains.
The objective of this prospective study was to evaluate the clinical and laboratory parameters distinguishing viral from nonviral lower respiratory tract infection in elderly patients and to determine the yield of virological diagnostics in elderly patients with lower respiratory tract infection. The study was conducted in a 184-bed geriatric department in a university hospital during 4 winter months. All consecutive elderly persons admitted with a lower respiratory tract infection were included in the study. Clinical and laboratory parameters, a nasopharyngeal swab, and serological results for respiratory viruses were obtained for all participants. Available blood and sputum cultures were analysed. A total of 165 elderly persons (mean age, 82+/-6.8 years) were hospitalised with a lower respiratory tract infection. Familial flu-like illness (OR, 4.25; 95%CI, 1.4-13), better functionality (OR, 4; 95%CI, 1.3-14.15), and leucocyte count <10(10)/l (OR, 3; 95%CI, 1.3-7.1) were predictive for viral lower respiratory tract infection. Sixty (36.5%) definite diagnoses (positive blood culture, viral culture, or serological test) and seven (4.2%) probable diagnoses (positive sputum culture) were obtained. An early diagnosis (within 72 h) was possible in 38 (23%) and a late diagnosis in 29 (17.6%) participants. A nasopharyngeal swab contributed in 60.5% of the cases to an early diagnosis. Viral culture identified half (22/43) of the lower respiratory tract infections caused by influenza but only one of six lower respiratory tract infections caused by respiratory syncytial virus. In conclusion, a history of flu-like illness in family members and a total leucocyte count within normal limits makes a viral cause more likely in elderly people hospitalised with a lower respiratory tract infection during winter. Viral culture and rapid antigen detection are insensitive in elderly patients hospitalised with a lower respiratory tract infection.
The purpose of the study presented here was to confirm the high yield of group B streptococci (GBS) on Granada medium for the detection of pregnant GBS carriers and to compare the results with those obtained using standard Columbia blood agar at two participating centers in Belgium. Culture results of the vaginorectal swabs obtained at the two centers were also compared. A total of 1,142 samples (838 in Leuven and 304 in Bonheiden) obtained from consecutive pregnant women were cultured onto both media. Of all GBS carriers 84.7% were detected on Columbia blood agar and 93.4% on Granada agar ( P<0.01, McNemar test). The addition of Granada agar was responsible for a 15% higher rate of detection of GBS carriers. As a result of this study, both participating hospitals will use a combination of Granada agar with Columbia blood agar for optimal GBS screening in the future.
Described here is the case of an 87-year-old man who developed fever, chills and discomfort caused by Streptobacillus moniliformis. This pathogen is one of the causes of rat-bite fever, an uncommon bacterial illness transmitted through a bite or scratch from a rodent or the ingestion of food or water contaminated with rat faeces. Cases of rat-bite fever are rarely reported in Spain. The patient reported no history of rat bite or rodent contact, and the only known risk factor was contact with a dog and a cat that were kept as pets. Streptobacillus moniliformis was isolated in two sets of blood cultures. This case represents what is believed to be the first report of bacteremia due to Streptobacillus moniliformis in Spain.
BACKGROUND: The aim of this project was to study the influence of pneumococci on nasopharyngeal epithelial integrity as a function of time and pneumococcal density. MATERIALS AND METHODS: Cell layers of an in vitro model of human nasopharyngeal epithelium were inoculated with different pneumococcal strains. The transepithelial electrical resistance (TEER), a measure of the integrity of the cell layers, and the pneumococcal concentration in the apical fluid on the epithelial cells were measured at different times after inoculation. RESULTS: Pneumococci caused a decrease in the TEER when a density of 1 x 107 CFU mL-1 was reached. The growth rate of pneumococci in our in vitro model differed between the strains tested and, for the same strain, between in vitro culture on the epithelial cells and broth culture. Differences in timing of the onset of decrease in the TEER between strains were the result of differences in growth rate on the epithelial cells. Antibiotic-induced lysis of pneumococci caused an immediate decrease in the TEER of the cell layers. CONCLUSION: Pneumococci cause a decrease in the TEER at a density of 1 x 107 CFU mL-1. Our hypothesis is that this decrease in the TEER is the result of quorum-induced lysis of the pneumococci.
Rothia dentocariosa is a rare cause of endocarditis. It occurs most frequently in patients with prior heart conditions. Although the clinical course is typically subacute, it has a high rate of complications. In particular, the reported incidence of mycotic aneurysms is as high as 25%. Penicillin is the treatment of choice, but additional complications may necessitate prompt surgical intervention. As far as we know, this paper reports the first case of repeated subarachnoid hemorrhages due to R. dentocariosa endocarditis.
The incidence of penicillin- and erythromycin-resistant strains of Streptococcus pneumoniae has increased considerably in Belgium. The medical charts of all patients with pneumococcal bacteraemia who were admitted to hospital over a period of 3 years (n = 136) were reviewed to identify treatment failure of outpatient antibiotic therapy. Twelve patients had received antibiotics for at least 48 h prior to admission. Four treatment failures received clarithromycin as pre-hospitalization therapy, and S. pneumoniae from all four patients were highly resistant to macrolides. Five patients failed on co-amoxiclav, whereas their S. pneumoniae were susceptible to penicillin and amoxicillin. This observation suggests that macrolide resistance is clinically relevant and leads to treatment failure, whereas suboptimal dosing may explain breakthrough pneumococcal bacteraemia in beta-lactam-treated patients.
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Interpretive reading analyses the complete resistance profiles of bacteria to multiple antibiotics and infers the resistance mechanisms present; it aids therapeutic choice and enhances surveillance data. We evaluated the Advanced Expert System (AES), which interprets MICs generated by the VITEK 2. Ten European laboratories tested 42 reference strains and 76-106 of their own strains, representing important resistance genotypes. Interpretive reading by the VITEK 2 AES achieved full agreement with genotype data for 88-89% of strains, with the correct mechanism identified as one of two possibilities for a further 5-6%. Mechanisms inferred with 90% agreement with reference data included methicillin resistance in staphylococci, glycopeptide resistance in enterococci, quinolone resistance in staphylococci and Enterobacteriaceae, AAC(6')-APH(2")-mediated aminoglycoside resistance in Gram-positive cocci, erm-mediated macrolide resistance in pneumococci, extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae and Pseudomonas aeruginosa, and acquired penicillinases in Enterobacteriaceae. VanA, VanB and VanC phenotypes of enterococci were distinguished reliably, and ESBL production was accurately inferred in AmpC-inducible species as well as Escherichia coli and Klebsiella spp. Mechanisms identified, but only as possibilities among several, included IRT-type beta-lactamases and individual aminoglycoside-modifying enzymes in Enterobacteriaceae. Most disagreements with reference data concerned pneumococci found to have high-level penicillin resistance by the VITEK 2 AES but previously determined, phenotypically, to have intermediate resistance. When ESBL production was inferred in E. coli and klebsiellae, the VITEK 2 AES edited susceptible results for cephalosporins (except cefoxitin) to resistant; when an acquired penicillinase was inferred in Enterobacteriaceae, piperacillin results were edited to resistant; and when staphylococci were found methicillin resistant, resistance was reported for all beta-lactams. Further editing may be desirable (e.g. of cephalosporin results for salmonellas inferred to have ESBLs).
The characteristics of bacteraemia with Streptococcus pneumoniae in children (0-4 years) and the elderly (> or =60 years) were compared over a 7 year period (1994-2000). Of a total of 7927 isolates of invasive S. pneumoniae studied in the national reference laboratory, 74% (n = 5837) were blood isolates. Of these 5837 S. pneumoniae bacteraemias, 843 (14%) occurred in children and 3144 (54%) in the elderly. The prevalence of penicillin resistance (MIC > or = 0.1 mg/L) in bacteraemic isolates rose from 8.2% to 18.9% (P = 0.03) in children and from 5.1% to 16.35% (P = 0.001) in the elderly over the study period. The prevalence of erythromycin resistance (MIC > or= 1 mg/L) in bacteraemic isolates was significantly higher in children than in the elderly (44.7% versus 25.7%, P = 0.001) and rose significantly over the 7 year period in the elderly (18.6-33.65%, P = 0.001). There were more serogroups and serotypes (SGTs) among the bacteraemic isolates obtained from the elderly compared with children (36 versus 26, P = 0.03). SGTs 6, 14, 18 and 19 cause significantly more bacteraemia in children than in the elderly. The opposite is true for SGTs 3, 7, 8, 9, 11, 12, 15, 20, 22 and 35. The new 7, 9 and 11 valent conjugate vaccine formulations cover significantly more bacteraemic SGTs in children than in the elderly (82%, 89.5% and 92% versus 55.5%, 65% and 77.5%, respectively; P = 0.001). The 23 valent polysaccharide vaccine provides a theoretical coverage of 95% in the elderly population. Our data indicate consideration of a vaccination strategy in the elderly population that combines the efficacy of conjugate vaccines with the broad coverage of the 23 valent polysaccharide vaccine.
The diagnosis of invasive aspergillosis (IA) in patients with hematologic disorders is not straightforward; lack of sensitive and specific noninvasive diagnostic tests remains a major obstacle for establishing a precise diagnosis. In a series of 362 consecutive high-risk treatment episodes that were stratified according to the probability of IA based on recently accepted case definition sets, the potential for diagnosis of serial screening for circulating galactomannan (GM), a major aspergillar cell wall constituent was validated. After incorporating postmortem findings to allow a more accurate final analysis, this approach proved to have a sensitivity of 89.7% and a specificity of 98.1%. The positive and negative predictive values equaled 87.5% and 98.4%, respectively. False-positive reactions occurred at a rate of 14%, although this figure might be overestimated due to diagnostic uncertainty. More or less stringent criteria of estimation could highly influence sensitivity, which ranged from 100% to 42%; the impact on other test statistics was far less dramatic. All proven cases of IA, including 23 cases confirmed after autopsy only, had been detected before death, although serial sampling appeared to be necessary to maximize detection. The excellent sensitivity and negative predictive value makes this approach suitable for clinical decision making. Unfortunately, given the species-specificity of the assay, some emerging non-Aspergillus mycoses were not detected. In conclusion, serial screening for GM, complemented by appropriate imaging techniques, is a sensitive and noninvasive tool for the early diagnosis of IA in high-risk adult hematology patients.
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