Cytomegalovirus Infection and Alzheimer's Disease: A Meta-Analysis.

BACKGROUND: Evidence on the association of cytomegalovirus (CMV) infection with Alzheimer's disease (AD) is scarce and the results are inconsistent. OBJECTIVE: To investigate the association of CMV infection with the risk of AD. METHODS: Observational studies on the relationship between CMV infection and AD were identified from PubMed, Embase, Web of Science, and the Cochrane Library until September 30, 2022. The quality of included studies was assessed using the Newcastle-Ottawa Scale. Random-effect meta-analysis was performed using a generic inverse-variance method, followed by sensitivity analyses and subgroup analyses based on study designs, regions, adjustments, and population types. RESULTS: Our search yielded 870 articles, of which 200 were duplicates and 663 did not meet the inclusion criteria, and finally yielded seven studies with 6,772 participants. No strong evidence was observed in the summary analysis for the association of CMV infection and risk of AD (odds ratio [OR] = 1.33; 95% confidence interval [CI]: 0.88, 2.03, I2 =69.9%). However, subgroup analysis showed that an increased risk of AD was detected in East Asians (OR = 2.39; 95% CI: 1.63, 3.50, I2 = 0.00%), cohort studies (OR = 1.99; 95% CI: 1.35, 2.94, I2 = 28.20%), and studies with confounder adjustment (OR = 2.05; 95% CI: 1.52, 2.77, I2 = 0.00%). CONCLUSIONS: This meta-analysis provides evidence to support the heterogeneity of the associations between CMV infection and AD. Future studies with larger sample sizes and multi-ethnic populations are necessary.

Joint impact of common risk factors on incident dementia: A cohort study of the Swedish Twin Registry.

BACKGROUND: As common risk factors of dementia, nine factors (low education, hearing loss, obesity, hypertension, smoking, depression, physical inactivity, diabetes and social isolation) were proposed. However, the joint impact of these factors on incident dementia is still uncertain; hence, we aimed to examine this impact. METHODS: We conducted a cohort study of 9017 cognitively intact individuals aged ≥ 65 years in the Swedish Twin Registry. The main exposure was the total number of reported risk factors (ranging from 0 to 9). Data on dementia diagnoses were based on clinical workup and national health registers. After estimating the adjusted hazard ratios of incident dementia, the population attributable fraction (PAF) was calculated. We then conducted additional analyses, including APOE ε4 status in a genotyped subsample (n = 2810) to check the relative impact of the main exposure and discordant twin pair (n = 1158) analysis to consider confounding by familial effects (shared genetic or familial environmental factors). RESULTS: The number of dementia cases was 1950 (21.6%). A dose-response relationship between the number of risk factors and incident dementia was observed; hazard ratio (95% confidence interval) per one-unit increment in number of risk factors was 1.07 (1.03 to 1.11). The PAF for the combination of the nine risk factors was 10.4%. The PAF of all nine risk factors was smaller than that of APOE ε4 genotype (20.8%) in the subsample. Discordant pair analysis suggested that the observed association was not likely explained by familial effects. CONCLUSION: The nine risk factors may have considerable impact as modifiable factors on incident dementia.

Is the matched extreme case-control design more powerful than the nested case-control design?

For time-to-event data, the study sample is commonly selected using the nested case-control design in which controls are selected at the event time of each case. An alternative sampling strategy is to sample all controls at the same (pre-specified) time, which can either be at the last event time or further out in time. Such controls are the long-term survivors and may therefore constitute a more 'extreme' comparison group and be more informative than controls from the nested case-control design. We investigate this potential information gain by comparing the power of various 'extreme' case-control designs with that of the nested case-control design using simulation studies. We derive an expression for the theoretical average information in a nested and extreme case-control pair for the situation of a single binary exposure. Comparisons reveal that the efficiency of the extreme case-control design increases when the controls are sampled further out in time. In an application to a study of dementia, we identified Apolipoprotein E as a risk factor using a 1:1 extreme case-control design, which provided a hazard ratio estimate with a smaller standard error than that of a 2:1 nested case-control design.

Local delivery of temozolomide via a biologically inert carrier (Temodex) prolongs survival in glioma patients, irrespectively of the methylation status of MGMT.

Glioma is the most common brain malignancy. Standard first-line therapy for glioma includes surgery, radiotherapy and systemic administration of temozolomide. However, temozolomide does not reach the brain in sufficient doses when administered orally and has poor efficiency in more than half of the patients. Strategies to improve the treatment of glial malignancies are therefore needed. We have recently developed a system (Temodex) for local administration of temozolomide by encapsulating the drug in a biologically inert matrix. Here, we assessed the effect of Temodex in combination with standard therapy in a small-scale clinical study. Since the efficacy of temozolomide therapy is known to depend on the methylation status of the O6-methylguanine-DNA methyltransferase gene (MGMT) promoter, we also analyzed whether the effect of Temodex was influenced by the methylation status of MGMT. Our data show that the combination of standard therapy and Temodex was more efficient than standard therapy alone, promoting the overall patient survival by up to 33 weeks. Moreover, the efficacy of Temodex was not dependent on the methylation status of MGMT. Local Temodex administration in combination with standard therapy thereby emerges as a novel therapeutic option, with applicability that is independent on the methylation status of the MGMT promoter.

Genetic susceptibility to cardiovascular disease and risk of dementia.

Several studies have shown cardiovascular disease (CVD) to be associated with dementia, but it is not clear whether CVD per se increases the risk of dementia or whether the association is due to shared risk factors. We tested how a genetic risk score (GRS) for coronary artery disease (CAD) affects dementia risk after CVD in 13 231 Swedish twins. We also utilized summarized genome-wide association data to study genetic overlap between CAD and Alzheimer´s disease (AD), and additionally between shared risk factors and each disease. There was no direct effect of a CAD GRS on dementia (hazard ratio 0.99, 95% confidence interval (CI): 0.98-1.01). However, the GRS for CAD modified the association between CVD and dementia within 3 years of CVD diagnosis, ranging from a hazard ratio of 1.59 (95% CI: 1.05-2.41) in the first GRS quartile to 1.91 (95% CI: 1.28-2.86) in the fourth GRS quartile. Using summary statistics, we found no genetic overlap between CAD and AD. We did, however, find that both AD and CAD share a significant genetic overlap with lipids, but that the overlap arose from clearly distinct gene clusters. In conclusion, genetic susceptibility to CAD was found to modify the association between CVD and dementia, most likely through associations with shared risk factors.

Metabolic and Hormonal Response to a Feed-challenge Test in Lean and Overweight Dogs.

BACKGROUND: Obese dogs risk poor life quality, creating a need for increased knowledge of metabolism in overweight dogs. OBJECTIVES: Investigate postprandial metabolic and hormonal responses to a high-fat mixed-meal in dogs and responses of lean versus overweight dogs. ANIMALS: Twenty-eight healthy intact male Labrador Retrievers were included. METHODS: Prospective observational study. Twelve dogs were grouped as lean (body condition score (BCS 4-5), 10 as slightly overweight (BCS 6), and 6 as overweight (BCS 6.5-8) on a 9-point scale. After an overnight fast, urine and blood samples were collected. Dogs were then fed a high-fat mixed-meal, and blood was collected hourly for 4 hours and urine after 3 hours. RESULTS: Postprandial concentrations of insulin and glucagon were increased at 1 hour (both P < 0.0001), triglycerides at 2 hours (P < 0.0001), and glucose at 3 hours (P = 0.004); and all remained increased throughout the feed-challenge in all dogs. Postprandial urine cortisol/creatinine ratio was higher than fasting values (P = 0.001). Comparing between groups, there was an overall higher triglyceride response in overweight compared to lean (P = 0.001) and slightly overweight (P = 0.015) dogs. Overweight dogs also had higher fasting cortisol/creatinine ratio compared to lean dogs (P = 0.024). CONCLUSIONS AND CLINICAL IMPORTANCE: Postprandial responses of dogs to a high-fat mixed-meal were similar to those previously reported in people. The higher postprandial triglyceride response and fasting cortisol/creatinine ratio in the overweight dogs could be early signs of metabolic imbalance. Thus, although overweight dogs often appear healthy, metabolic alterations might be present.

Effect of tablets containing probiotic bacteria (Lactobacillus reuteri) on early caries lesions in adolescents: a pilot study.

The objective of the study was to investigate the effect of tablets containing probiotic lactobacilli on early caries lesions in adolescents with quantitative light-induced fluorescence (QLF). 36 healthy adolescents of both sexes (12-17 years of age) were enrolled and randomly allocated to a placebo-controlled trial with two parallel groups. The test group received two tablets daily containing two strains of Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) for a period of three months, while the control group got identical placebo tablets without live bacteria. The primary outcome was QLF-readings (change in fluorescence, ΔF and lesion area, mm2) at baseline and after 3 months, conducted at two buccal sites of each individual, pre-selected with clearly visible clinical signs of enamel demineralisation (white spots). Significantly more premolars were allocated to the placebo group, while the test group had more incisors (P<0.05). There were no statistically significant differences in fluorescence values between the groups, neither at baseline, nor at the follow-up. There was however a significant decrease in fluorescence over time in the test group, but not in the placebo group (P<0.05). No alterations of the lesion area (ΔA) were found in any group. The inter-examiner intra-class correlation coefficient-value for QLF-readings was excellent. No side- or adverse effects were reported during the intervention period. This pilot study found a significant decrease over time in the test group. However, no statistically significant differences in fluorescence values between the groups were found. Hence, the null hypothesis could not be rejected.

Increased concentrations of C-reactive protein but not high-mobility group box 1 in dogs with naturally occurring sepsis.

Sepsis is difficult to diagnose and remains a common mortality cause worldwide in both humans and animals. The uterine infection pyometra causes sepsis in more than half of affected dogs and therefore allows the natural physiological development of sepsis to be studied. To find a sepsis-specific biochemical marker that could be combined with conventional clinical criteria for a more robust and quick diagnosis of sepsis, we measured systemic concentrations of high-mobility group box 1 (HMGB1) in 23 healthy control dogs and in 27 dogs with pyometra, 74% of which had sepsis. We also measured concentrations of the major acute phase protein C-reactive protein (CRP) and an indicator for endotoxaemia, prostaglandin F2α metabolite (PGM) to assess the relative contribution of HMGB1 to the detection of systemic inflammation and endotoxaemia. We found that HMGB1 concentrations, in line with concentrations of CRP and PGM, were significantly increased in dogs with pyometra, and that concentrations of CRP, but not HMGB1, were significantly higher in dogs with sepsis compared to dogs without sepsis. Although serum HMGB1 did not differ between dogs with or without sepsis and was not correlated with either CRP or PGM concentrations, HMGB1 was correlated with the total white blood cell counts, suggesting an independent regulation and involvement in inflammation.

Cytokines as immunological markers for systemic inflammation in dogs with pyometra.

Pyometra is a disease in dogs caused by bacterial infection of the uterus and resulting in SIRS (systemic inflammatory response syndrome) in nearly 6 of 10 cases. Clinical diagnostic criteria for SIRS are relatively unspecific, and biomarkers for the diagnosis of pyometra and SIRS in dogs are needed. Serum samples from 32 dogs were used in this study and grouped into dogs with pyometra and SIRS, dogs with pyometra without SIRS and healthy controls. The serum concentrations of IFN-γ, IL-4, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18 and TNF-α were measured using multiplex analyses. The serum concentrations of CRP (C-reactive protein) were determined using sandwich ELISA. IL-7, IL-8, IL-15, IL-18 and TNF-α were detected in >94% of samples. IL-10 was detected in 28% of samples, and IL-4, IL-6 and IFN-γ were undetectable. Higher serum concentrations of IL-7 (p < 0.05) were detected in SIRS-positive dogs with pyometra (n = 13) as compared with healthy controls (n = 11). The concentrations of IL-8 were higher in SIRS-positive dogs with pyometra compared to the SIRS-negative group (n = 8; p < 0.05). Positive correlations of IL-15 with IL-18 (p < 0.0001) and with the concentrations of IL-7 (p < 0.0001 for both) were found, although there was no significant difference between groups. Furthermore, IL-15 correlated with concentrations of CRP (p < 0.05), which were higher in dogs with pyometra compared to controls (p < 0.0001). Our data suggest a role of several cytokines in the development of a systemic disease in dogs with pyometra and a possible diagnostic value for serum CRP, IL-7, IL-15 and IL-18 in canine SIRS caused by pyometra.

A new multifunctional platform based on high aspect ratio interdigitated NEMS structures.

A multifunctional NEMS platform based on a mass-producible, surface relief grating has been developed and fabricated directly in polymer materials. The pattern consists of high aspect ratio interdigitated nanometer-sized pairs of walls and can be produced in a low-complexity one-step patterning process with nanoimprint lithography. In this paper, we demonstrate the usefulness of the platform primarily by showing an application as a high-sensitivity mass sensor in air. The sensors, which are based on the high frequency resonant response of around 200 MHz, show a mass responsivity of the order of 0.1 Hz/zg per wall at room temperature and in ambient air. Their ability to selectively adsorb airborne target molecules, such as thiols, is also demonstrated. We also show that the same device can function as a varactor for electronic circuits based on its large tunable capacitive range.

Patterns of mutations in target genes in septicemia isolates of Escherichia coli and Klebsiella pneumoniae with resistance or reduced susceptibility to ciprofloxacin.

Thirty-two Escherichia coli and 21 Klebsiella pneumoniae septicemia isolates with varying degrees of resistance to ciprofloxacin were analyzed for the presence of point mutations within the quinolone-resistance target genes. The number of mutations observed in the resistant isolates agreed with the level of ciprofloxacin resistance in both species. Such isolates were also resistant to nalidixic acid. Isolates with borderline susceptibility to ciprofloxacin, on the other hand, behaved differently in the two species. In E. coli all the isolates harbored at least one mutation and these isolates were also resistant to nalidixic acid, while no mutations were detected in the K. pneumoniae isolates, and susceptibility to nalidixic acid was unpredictable. Therefore, nalidixic acid cannot be used as a class representative. Time-kill curve studies on an isolate with borderline susceptibility from each species showed higher degrees of resistance to ciprofloxacin in comparison to that of the wild-type E. coli. A previously unreported parC mutation, S57-->T, was detected in a resistant E. coli isolate and might expand the QRDR of this gene. Normalized resistance interpretations of histograms confirmed the setting of microbiological zone breakpoints for ciprofloxacin testing.

Wastewater sludge as a resource: sludge disposal strategies and corresponding treatment technologies aimed at sustainable handling of wastewater sludge.

The paper discusses different strategies for the disposal of wastewater sludge, particularly the "use on land" strategy and the "productification" strategy. In the "use on land" strategy the new regulations in Europe call for stabilization as well as disinfection of sludge to be used on land. The paper discusses the design and operation experiences with stabilization/disinfection methods in Norway where such treatment has been compulsory since 1995. In the "productification" strategy it is differentiated between the production of "bio-soils" and production of specific products (energy, nutrients, coagulants etc) and the "marketability" of these products is evaluated. An example of a sludge treatment concept aimed at recycling--the KREPRO process--is presented.

Relationship between depressive symptomatology and the subcortical brain syndrome in dementia.

OBJECTIVES: the aim of the present study was to elucidate a possible relationship between depressive symptomatology and regional brain symptomatology in demented patients. METHODS: 170 consecutive inpatients were studied. They suffered from Alzheimer's disease (103 patients), vascular dementia (48 patients), or frontotemporal dementia (19 patients). The patients underwent a neuropsychiatric investigation, which included assessments of (1) depression, and (2) regional brain symptomatology. Depressive symptomatology was assessed as presence of (a) depressed mood, and (b) anxiety. In the further statistical analysis, the presence of depressed mood and/or anxiety was also evaluated. The principle of the regional symptom analysis was the successive aggregation of observable symptom variables, leading to the final determination of four possible regional brain syndromes (frontal, subcortical, parietal and global), by way of the Stepwise comparative status analysis (STEP). The possible correlations between regional brain symptomatology and depressive symptomatology were analysed by means of (a) chi(2) statistics, and (b) a logistic regression analysis in which confounding factors were included (age, degree of dementia, duration). RESULTS: the subcortical syndrome correlated with depressed mood (chi(2), p = 0.002; logistic regression, p = 0.002). A negative correlation was noted between the parietal syndrome and depressed mood (p = 0.010 and p = 0.013, respectively). No other significant correlations between presence of regional brain syndrome and presence of depressive symptomatology could be seen. CONCLUSIONS: demented patients with a clinically established subcortical dysfunction appear to be more susceptible to depressive symptomatology. The results of this study also suggest that posterior brain dysfunction in dementia is not correlated with depressive symptomatology.

Treatment of Alzheimer's disease with clioquinol.

As heavy metal ions may be implicated in the formation of senile plaques in Alzheimer-afflicted brains, treatment with clioquinol was tested in 20 patients with Alzheimer's disease. Clioquinol is a chelator that crosses the blood-brain barrier and has greater affinity for zinc and copper ions than for calcium and magnesium ions. Treatment was given for 21 days at doses of 20 mg/day to 10 patients and 80 mg/day to another 10 patients. The study was blind to the dosages but included no controls. Cerebrospinal fluid (CSF) investigations revealed a significant increase at day 7 and a decrease at day 21 in Tau protein and growth-associated protein (GAP43). These proteins are increased in Alzheimer's disease and considered as rather stable markers. The initial increase may indicate a temporary cytotoxicity to the brain and/or an increased release into the CSF from stores in the tissue, possibly from senile plaques where the proteins are accumulated. The levels of CSF-Tau protein correlated positively and significantly with the serum levels of copper and also with the serum copper/zinc ratio. Clinical ratings showed slight improvement after 3 weeks treatment with clioquinol in this open study.

Tacrine and rate of progression in Alzheimer's disease--relation to ApoE allele genotype.

Today, cognitive impairment can be successfully treated with acetylcholine esterase inhibitors (AChE-I) in many, but not all, patients with Alzheimer's disease (AD). To investigate the relation between tacrine treatment, inheritance of ApoE epsilon4 alleles, and rate of progression, the differences in MMSE and CIBIC scores (efficacy parameters) after 6 and 12 months of tacrine (an AChE-I) treatment were investigated in 145 AD patients. Of these, 84 were ApoE epsilon4-positive (ApoE4) and 61 were ApoE epsilon4-negative (ApoE2-3). No differences were found after 6 months of treatment, but after 12 months the CIBIC scores revealed that the ApoE4 patients had declined more than the ApoE2-3 patients (p < 0.05). No differences were found for the last 6 months of treatment. The results primarily suggest a faster rate of decline in the ApoE4 AD compared to the ApoE2-3, but may also reflect that ApoE epsilon4 genotype inheritance is a negative predictor of treatment effect of tacrine in AD patients.

Fluconazole and voriconazole multidisk testing of Candida species for disk test calibration and MIC estimation.

Fluconazole and voriconazole MICs were determined for 114 clinical Candida isolates, including isolates of Candida albicans, Candida glabrata, Candida krusei, Candida lusitaniae, Candida parapsilosis, and Candida tropicalis. All strains were susceptible to voriconazole, and most strains were also susceptible to fluconazole, with the exception of C. glabrata and C. krusei, the latter being fully fluconazole resistant. Single-strain regression analysis (SRA) was applied to 54 strains, including American Type Culture Collection reference strains. The regression lines obtained were markedly different for the different Candida species. Using an MIC limit of susceptibility to fluconazole of < or =8 microg/ml, according to NCCLS standards, the zone breakpoint for susceptibility for the 25-microg fluconazole disk was calculated to be > or =18 mm for C. albicans and > or =22 mm for C. glabrata and C. krusei. SRA results for voriconazole were used to estimate an optimal disk content according to rational criteria. A 5-microg disk content of voriconazole gave measurable zones for a tentative resistance limit of 4 microg/ml, whereas a 2.5-microg disk gave zones at the same MIC level for only three of the species. A novel SRA modification, multidisk testing, was also applied to the two major species, C. albicans and C. glabrata, and the MIC estimates were compared with the true MICs for the isolates. There was a significant correlation between the two measurements. Our results show that disk diffusion methods might be useful for azole testing of Candida isolates. The method can be calibrated using SRA. Multidisk testing gives direct estimations of the MICs for the isolates.

[Depression and anxiety in the elderly still underdiagnosed. SSRI preparations in conjunction with psychotherapy provide effective treatment]. / Depression och ångest hos äldre fortfarande underdiagnostiserade. SSRI-preparat i förening med psykoterapi effektiv behandling.

Depression and anxiety disorders in the elderly are common and under-diagnosed. As depressed elderly people often present with more somatic than psychiatric symptoms, diagnosis is difficult for the general practitioner. The Geriatric Depression Scale can be used as a screening instrument for diagnosis in the elderly. The etiology of depression and anxiety disorders is multifactorial. Important risk factors are psychological stress, reduced absorption of essential nutrients such as folacin and vitamin B12, and biological changes in the brain associated with aging. Selective serotonin reuptake inhibitors (SSRIs) are the drugs of choice in the treatment of elderly people with depression and anxiety disorders. Currently, the most widely used SSRI is citalopram, which according to controlled trials has an effect not only on depressed mood but also on anxiety. The use of SSRIs combined with support and psychotherapy elicits a positive response in nearly 90% of elderly patients. In Sweden, the use of antidepressants is currently most common in the age group 75-80 years, expressed in DDD (defined daily doses/1,000 inhabitants). This indicates a fairly active treatment of the elderly in Sweden.

Hyperactivity in the hypothalamic-pituitary-adrenal axis in demented patients with delirium.

Occurrence of delirium is known to be related to, among other things, organic brain disorder, somatic disease and old age. It has been hypothesized that delirium is also associated with stress. Disturbances of the hypothalamic-pituitary-adrenal (HPA) system have been found in delirious patients in various studies. The aim of the present study was to determine the activity in the HPA axis in demented patients to ascertain whether the stress regulating system was more disturbed in patients with delirium than in those without delirium. Demented inpatients with no acute medical illness were included in the study. Basal cortisol levels in serum were measured and dexamethasone suppression test (DST) was performed. The most important finding of the study was a strong relationship between delirium and DST pathology irrespective of age and severity of dementia. It is suggested that certain demented individuals have an impaired HPA system and a low delirium threshold and respond to stress with delirium.

Reduction of the synaptic protein rab3a in the thalamus and connecting brain regions in post-mortem schizophrenic brains.

Although the psychotic symptoms in schizophrenia can be alleviated by treatment with dopaminergic receptor antagonists, the etiology and underlying neurochemical pathology remains obscure. Both neuropathological and magnetic resonance imaging studies have found evidence for neuronal loss and atrophy in the thalamus in schizophrenia, implicating this key structure for gating information to cortical areas in the pathophysiology. Recent studies have also found evidence of synaptic loss in the thalamus in schizophrenia. To further examine possible synaptic disturbances, we studied the synaptic related protein rab3a as a marker for synaptic density, using both quantitative Western blotting and immunohistochemistry. The material consisted of brains from 22 schizophrenic patients (mean age 79.3 years), and 24 control subjects (74.8 years). Reduced rab3a protein levels were found in the left thalamus in schizophrenia (0.47 +/- 0.17 vs. 1.00 +/- 0.18; p < 0.0001), while a less marked decrease was found also in the right thalamus (0.75 +/- 0.13 vs. 1.00 +/- 0.09; p < 0.0001). Immunohistochemistry, performed on two schizophrenic and two control brains, revealed that rab3a immunoreactivity was most reduced in the left anterior and mediodorsal thalamic nuclei. Therefore, we extended the study to brain regions connected these thalamic nuclei. Reduced rab3a protein levels were found schizophrenia also in the frontal cortex, hippocampus, gyrus cinguli, and parietal cortex, while no significant differences were found in the temporal cortex, or in cerebellum. The reduction in rab3a was not found to be secondary to confounding factors such as age-differences, post-mortem delay time, generalized brain atrophy, or antipsychotic medication. Therefore, the reduction of rab3a probably reflects synaptic disturbances, possibly synaptic loss, in the limbic system and neocortical areas, in schizophrenia. This part of the brain is known to be involved in behavioral and emotional control, and thus to be crucial for higher mental functions, suggesting that synaptic disturbances in the limbic system may be of importance in the development of psychotic symptoms in schizophrenia.

Antibiotic medication and bacterial resistance to antibiotics: a survey of children in a Vietnamese community.

OBJECTIVE: To investigate antibiotic use and antibiotic susceptibility of respiratory tract pathogens in children aged 1-5 years in Bavi, Vietnam. METHOD: Nasopharynx and throat specimens were collected from 200 children from randomly selected households in a demographically defined population. Respiratory isolates were tested for antibiotic susceptibility according to the standard disk diffusion method. A questionnaire survey of carers elicited information on type of antibiotic used, duration of treatment, where the antibiotics had been purchased, type of treatment information retained by carers and episodes of illness preceding the study. RESULTS: 82% of the children had at least one symptom of acute respiratory tract infection (ARI) in the 4 weeks prior to the study, and of these 91% were treated with antibiotics. The most commonly used antibiotics were ampicillin (74%), penicillin (12%), amoxicillin (11%), erythromycin (5%), tetracycline (4%) and streptomycin (2%). Ampicillin was used for 3.3 days on average (SD:1.8) and penicillin for 2.6 days (SD:0.7). When deciding which antibiotic to use, 67% of the carers consulted the pharmacy seller, 11% decided themselves and 22% followed the doctor's prescription. The carrier rate of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis was 50%, 39% and 17%, respectively. Isolates from 145 children were susceptibility tested, and 74% were found to carry resistant pathogens. Of the tested isolates, 90% of S. pneumoniae, 68% of H. influenzae and 74% of M. catarrhalis were resistant to at least one antibiotic. The mean number of antibiotics (susceptible strains excluded) to which resistance was found was 2.0 (SD:1.2), 2.5 (SD:1.8) and 2.1 (SD:0.9), respectively. S. pneumoniae and H. influenzae showed high resistance to tetracycline (88% and 32%, respectively), trimethoprim/sulphonamide (32% and 44%), and chloramphenicol (25% and 24%). 23% of S. pneumoniae were erythromycin-resistant and 18% of H. influenzae isolates were resistant to ampicillin. There was a significant difference in ampicillin and penicillin resistance between the group of children previously treated with beta lactam antibiotics and the group of children who did not receive antibiotics. CONCLUSION: As reported by the carers, children in Bavi are treated with antibiotics frequently. Most antibiotics were obtained without consulting a doctor. High levels of antibiotic resistance and high prevalence of multidrug-resistant strains were found among respiratory pathogens. The existence of a large reservoir of resistance genes among children in low-income countries represents a threat to the success of antibiotic therapy throughout the world. Multi-faceted programmes to improve rational use of antibiotics in Vietnam are urgently needed.