E. Van Wijngaerden

Prevalence and characteristics of multinucleoside-resistant human immunodeficiency virus type 1 among European patients receiving combinations of nucleoside analogues.

ABSTRACT The prevalence and the genotypic and phenotypic characteristics of multinucleoside-resistant (MNR) human immunodeficiency virus type 1 (HIV-1) variants in Europe were investigated in a multicenter study that involved centers in nine European countries. Study samples (n = 363) collected between 1991 and 1997 from patients exposed to two or more nucleoside analogue reverse transcriptase inhibitors (NRTIs) and 274 control samples from patients exposed to no or one NRTI were screened for two marker mutations of multinucleoside resistance (the Q151M mutation and a mutation with a 2-amino-acid insertion at codon 69, T69S-XX). Q151M was identified in six of the study samples (1.6%), and T69S-XX was identified in two of the study samples (0.5%; both of them T69S-SS), but both patterns were absent among control samples. Non-NRTI (NNRTI)-related changes were observed in viral strains from two patients, which displayed the Q151M resistance pattern, although the patients were NNRTI naive. The patients whose isolates displayed multinucleoside resistance had received treatment with zidovudine and either didanosine, zalcitabine, or stavudine. Both resistance patterns conferred broad cross-resistance to NRTIs in vitro and a poor response to treatment in vivo. MNR HIV-1 is found only among multinucleoside-experienced patients. Its prevalence is low in Europe, but it should be closely monitored since it seriously limits treatment options.

Phenotypic assays and sequencing are less sensitive than point mutation assays for detection of resistance in mixed HIV-1 genotypic populations.

The sensitivity and discriminatory power of the 151 and 215 amplification refractory mutation system (ARMS) were evaluated, and their performance for the detection of drug resistance in mixed genotypic populations of the reverse transcription (RT) gene of HIV-1 were compared with T7 sequencing, cycle sequencing, the line probe assay (LiPA) HIV-1 RT test, and the recombinant virus assay (RVA). ARMS and the LiPA HIV-1 RT test were shown to be able to detect minor variants that in particular cases comprised only 1%. T7 sequencing on an ALF semiautomated sequencer could correctly score mixtures only when variants were present at 50%. Cycle sequencing on an ABI PRISM 310 improved the sensitivity for mixtures to about 25%. Using RVA, it was shown that at least 50% of the virus population needed to carry the resistance mutation at codon 184 to afford phenotypic resistance against lamivudine. The two point mutation assays therefore proved to be more sensitive methods than sequencing and RVA to reliably determine a gradual shift in HIV-1 drug resistance mutations in follow-up of patients infected with HIV-1. In 4 of 5 treated patients who were followed by ARMS, a gradual shift in resistant genotypic populations was observed during a period of 6 to 19 months. For 1 patient, a shift from wild to mutant type at position 151 occurred within 2 months, without mixed genotypic intermediate types being detected.

Families affected by HIV: Parents’ and children's characteristics and disclosure to the children

The reduced risk of mother-to-child transmission due to improved HIV treatment has resulted in an increasing number of healthy children born to mothers living with HIV. The studys objective was to identify the number of parents or caregivers in a sample of persons living with HIV in Flanders, the number of HIV-affected children as well as specific family-related characteristics. Using a structured survey quantitative data were assessed on a total of 628 patients at three Flemish Aids reference centres. Qualitative data were collected in a small sub-sample of African caregivers living in Flanders. Twenty-seven per cent of the overall sample had children younger than 18 years, totalling 165 HIV-affected families with 279 children. Parents from developing countries had significantly more children than European parents. One hundred and eighty-two (68%) of all children were HIV-negative, while the HIV status of 75 (28%) was unknown. Disclosure rate was low: 26 (10%) children were aware of the parental HIV disease. The study shows that HIV-affected families have to deal with complex psychosocial issues such as migration, family illness, family secrecy around HIV and disclosure. Service implications are discussed.

Candidal Vertebral Osteomyelitis: Report of 6 Patients, and a Review

The incidence of deep-seated candidal infection is increasing, but candidal vertebral osteomyelitis is still rare. We describe 6 patients recently treated in our hospital. Conservative treatment failed in all. We reviewed the literature and identified 59 additional cases of candidal vertebral osteomyelitis. Candidemia was documented in 61.5% of them. The interval between the diagnosis of candidemia and the onset of symptoms of vertebral osteomyelitis varied widely, from days to >1 year. In patients without documented candidemia, there was a similar interval between the occurrence of risk factors for candidemia (present in 72% of the patients) and the onset of symptoms of vertebral osteomyelitis. Clinical, laboratory, and radiological findings are not specific for candidal spondylodiskitis. Final diagnosis is determined by means of culture of a biopsy specimen from the infected vertebra or disk. Treatment consisted of prolonged antifungal treatment, and it often included surgery. On the basis of our experience (for all 6 patients, initial conservative treatment with only antifungals failed), we recommend consideration of early surgical debridement in combination with prolonged antifungal therapy.

Saccharomyces fungemia complicating Saccharomyces boulardii treatment in a non-immunocompromised host.

Sir: Saccharomyces boulardii (SB) is used for the prevention and treatment of Clostridium difficile-related diarrhoea and in one study it was given successfully for the prevention of enteral feeding-associated diarrhoea in the ICU [1]. There are conflicting, but mostly positive, results about the efficacy of SB for the prevention of antibiotic-associated diarrhoea. Treatment with SB is generally thought to be safe as it only colonises mucosal surfaces. We report the case of a patient who developed fungemia with Saccharomyces cerevisiae (SC) during treatment with SB for enteral feeding-associated diarrhoea. A 74-year-old male patient was hospitalised with hemiplegia due to a subarachnoidal haematoma and underwent neurosurgery. During his stay in the ICU he received enteral nutrition through a nasogastric tube. Major diarrhoea developed (5±10 liquid stools a day), repeated testing for Clostridium difficile and other enteropathogens was negative. The problem persisted after enteral nutrition was stopped and treatment with SB (Perenterol, Biodiphar, Brussels) was started at two capsules (50 mg each) 6 times a day. After several days of treatment he developed sepsis with Klebsiella oxytoca and SC (2 of 3 aerobe blood culture bottles were positive). Catheter-tip culture of the only (intravenous) catheter the patient had remained sterile. Antibiotic treatment and fluconazole 200 mg i. v.b. i. d. were started. On clinical examination the patient had a severely distended abdomen. A sigmoidoscopy showed severe inflammation of the mucosal surface without pseudomembranes and pathological findings were unrevealing (aspecific inflammation). Subsequent blood cultures remained negative. The patient died 4 weeks later. Autopsy showed diffuse mucosal inflammation of the colon and a perforation of the sigmoid with faecal peritonitis. Biopsies of the colonic mucosa revealed multiple ulcerations, some of them causing perforation. The aetiology of the colitis remained uncertain. Yeast infection could not be demonstrated at necropsy. To the best of our knowledge, this is the second report of SC fungemia in a non-immunocompromised host receiving SB treatment for diarrhoea [2]. We think the fungemia was caused by translocation through the intestinal wall because this patient had macroscopic and microscopic colitis as an obvious portal of entry. We were unable to show with certainty that the strain of the patient was the same as the one administered, because the blood cultures were no longer available for genotypic differentiation. In most cases of SB fungemia in ICU, intravascular catheters were considered the probable portal of entry. Transmission via hands that were contaminated while manipulating Saccharomyces capsules for administration via nasogastric tubes (and subsequent contamination of the catheter) was the likely explanation. Transmural migration of Saccharomyces in critically ill patients, however, remains a concern. This case illustrates that there should be concern about the safety of SB in patients with active colitis although it is uncertain if the patients death was related to the fungemia. Colonic ulceration might predispose to translocation of SB through the intestinal wall even in the non-immunocompromised host. It has to be mentioned that although our patient was, generally speaking, nonimmunocompromised, a critically ill patient can probably be considered to be immunocompromised [3].

Three cases of destructive native valve endocarditis caused by Staphylococcus lugdunensis

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.

IMPLEMENTATION OF PRETRAVEL ADVICE : GOOD FOR MALARIA, BAD FOR DIARRHOEA

Abstract Pretravel immunisations and health advice can substantially reduce the incidence of travel-related diseases. The aim of this study was to evaluate the implementation of pretravel advice among a homogenous group of students, who received similar written information on vaccination requirements and health advice. They were referred to the travel clinic (50 %) or a general practitioner (50 %) for vaccination, counselling and prescriptions. Eighty-four out of 110 students (76 %) returned the questionnaire. Insect repellent was used by all and only 10 used the repellent for less than 75 % of the time spent in malaria endemic areas. Malaria chemoprophylaxis was taken by all but one : chloroquine plus proquanil by 12 and mefloquine by 71. Reported compliance with the dosing regimen was optimal in 64 students, 9 missed one dose and 10 stopped too early. Side effects due to antimalarials were reported by 25 (30 %). Diarrhoea during travel occurred in 43 students (51 %). Loperamide was used by 34 students with diarrhoea (79 %), but only 2 out of 27 students with moderate to severe diarrhoea used the recommended self-treatment with a fluoroquinolone antibiotic. In conclusion, the recommendations of malaria prophylaxis were well implemented by most travellers despite a high incidence of self-reported side effects to antimalarials. The incidence of traveller’s diarrhoea was high and the recommendation for early self-treatment of moderate to severe diarrhoea with a fluoroquinolone antibiotic in combination with loperamide was not put into practice.

Baseline HIV Type 1 Genotypic Resistance to a Newly Added Nucleoside Analog Is Predictive of Virologic Failure of the New Therapy

We evaluated the predictive value of baseline HIV-1 genotypic resistance mutations for failure of a nucleoside reverse transcriptase inhibitor (NRTI) containing therapy. The change in therapy of 88 HIV-1-infected patients was analyzed retrospectively, relating the genotypic resistance profile at baseline to the evolution of viral load and CD4+ T cell counts. Genotypic resistance at baseline and at 6 months was evaluated with the LiPA HIV-1 RT, which detects mutations at codons 41, 69, 70, 74, 184, and 215. At 1 to 3 months after change in therapy, patients without preexisting resistance mutations to the new drug (group S) had a significantly better evolution in viral load (reduction of 0.37 log(10)) compared with patients with known preexisting resistance mutation(s) (group R) (increase of 0.08 log(10)). This difference was particularly striking for patients with the baseline M184V mutation and whose treatment was modified by the addition of lamivudine. After 6 months the median difference in viral load evolution between the two groups increased to 0.61 log(10): the viral load of patients of group S was still 0.18 log(10) below baseline while patients of group R had an increase of 0.43 log(10) in viral load above baseline. Changes in CD4+ T cell counts were not significantly different. The evolution in viral load in HIV-1-infected patients with and without baseline resistance mutation(s) toward a newly added NRTI is significantly different at 1-3 months and at 6 months after changing or adding one NRTI.

New insights in the pathogenesis of foreign body infections with coagulase negative staphylococci

Abstract Foreign body infections by coagulase negative Staphylococci are an important and growing problem in our hospitals. Only recently have we started to get some data on the specific virulence factors that permit the otherwise non-pathogenic Coagulase Negative Staphylococci (CNS) to be so successful in causing foreign body infections. Adherence of the Coagulase Negative Staphylococci to the foreign body is a first and crucial step. Several genes and gene-products have been identified that enhance staphylococcal adherence to biomaterials. Adherence is followed by accumulation; in this phase the Coagulase negative Staphylococci organise themselves into a complex multilayer of cells covered with polysaccharide. This we call the biofilm. Finally coagulase negative Staphylococci undergo complex and as yet non-defincd metabolic changes that in combination with biofilm formation allow them to persist on the foreign body and become less susceptible to antibiotics. Few data are available on the factors involved in the accumulation and persistence phase.

Mycobacterium genavense infection in a solid organ recipient: a diagnostic and therapeutic challenge

Renal transplant recipients are highly susceptible to infections caused by uncommon pathogens because of their immunocompromised state. We report a case of disseminated Mycobacterium genavense infection in a patient with a combined renal and cardiac transplant. Diagnosing M. genavense infections remains a challenge because of the absence of specific clinical symptoms in combination with the difficulties of culturing the organism using standard mycobacterial culture procedures. This clinical case demonstrates the importance of molecular techniques as part of the initial work‐up in order to rapidly establish the diagnosis.