Air dispersal of multi-drug-resistant organisms including meticillin-resistant Staphylococcus aureus, carbapenem-resistant Acinetobacter baumannii and carbapenemase-producing Enterobacterales in general wards: surveillance culture of air grilles

BACKGROUND

The environmental surveillance of air grilles in clinical areas has not been systematically analysed.

METHODS

Samples were collected from frequently touched items (N = 529), air supply (N = 295) and exhaust (N = 184) grilles in six medical and 11 surgical wards for the cultures of multi-drug-resistant organisms (MDROs): meticillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenemase-producing Enterobacterales (CPE), and isolates were selected for whole-genome sequencing (WGS). The contamination rates were correlated with the colonization pressures of the respective MDROs.

RESULTS

From 3rd October to 21st November 2023, 9.8% (99/1008) of the samples tested positive, with MRSA (24.2%, 24/99), CRAB (59.6%, 59/99) and CPE (2.0%, 2/99), being the only detected MDROs. The contamination rate in air exhaust grilles (26.6%, 49/184) was significantly higher than in air supply grilles (5.8%, 17/295; P<0.001). The contamination rate of air exhaust grilles with any MDRO in acute medical wards (73.7%, 14/19) was significantly higher than in surgical wards (12.5%, 4/32; P<0.001). However, there was no difference in the contamination rate of air exhaust grilles between those located inside and outside the cohort cubicles for MDROs (27.1%, 13/48 vs 28.8%, 30/104; P=0.823). Nevertheless, the weekly CRAB colonization pressure showed a significant correlation with the overall environmental contamination rate (r = 0.878; 95% confidence interval (CI): 0.136-0.986; P=0.004), as well as with the contamination rate in air supply grilles (r = 0.960; 95% CI: 0.375-0.999; P<0.001) and air exhaust grilles (r = 0.850; 95% CI: 0.401-0.980; P=0.008). WGS demonstrated clonal relatedness of isolates collected from patients and air exhaust grilles.

CONCLUSIONS

Air grilles may serve as MDRO reservoirs. Cohort nursing in open cubicles may not completely prevent MDRO transmission through air dispersal, prompting the consideration of future hospital design.

Sex-Dependent Efficacy of Dietary Fiber in Pediatric Functional Abdominal Pain

BACKGROUND & AIMS

Functional abdominal pain disorders (FAPDs) are more prevalent in female patients. Dietary fiber may alleviate FAPD symptoms; however, whether this effect is sex dependent remains unclear. We investigated the sex dependency of dietary fiber benefit on abdominal pain in children with FAPDs and explored the potential involvement of the gut microbiome.

METHODS

In 2 cross-sectional cohorts of children with FAPDs (n = 209) and healthy control individuals (n = 105), we correlated dietary fiber intake with abdominal pain symptoms after stratifying by sex. We also performed sex-stratified and sex-interaction analyses on data from a double-blind trial in children with irritable bowel syndrome randomized to psyllium fiber (n = 39) or placebo (n = 49) for 6 weeks. Shotgun metagenomics was used to investigate gut microbiome community changes potentially linking dietary fiber intake with abdominal pain.

RESULTS

In the cross-sectional cohorts, fiber intake inversely correlated with pain symptoms in boys (pain episodes: r = -0.24, P = .005; pain days: r = -0.24, P = 0.004) but not in girls. Similarly, in the randomized trial, psyllium fiber reduced the number of pain episodes in boys (P = .012) but not in girls. Generalized linear regression models confirmed that boys treated with psyllium fiber had greater reduction in pain episodes than girls (P = .007 for fiber × sex × time interaction). Age, sexual development, irritable bowel syndrome subtype, stool form, and microbiome composition were not significant determinants in the dietary fiber effects on pain reduction.

CONCLUSIONS

Dietary fiber preferentially reduces abdominal pain frequency in boys, highlighting the importance of considering sex in future dietary intervention studies for FAPDs. (ClincialTrials.gov, Number NCT00526903).

The pan-microbiome profiling system Taxa4Meta identifies clinical dysbiotic features and classifies diarrheal disease

Targeted metagenomic sequencing is an emerging strategy to survey disease-specific microbiome biomarkers for clinical diagnosis and prognosis. However, this approach often yields inconsistent or conflicting results owing to inadequate study power and sequencing bias. We introduce Taxa4Meta, a bioinformatics pipeline explicitly designed to compensate for technical and demographic bias. We designed and validated Taxa4Meta for accurate taxonomic profiling of 16S rRNA amplicon data acquired from different sequencing strategies. Taxa4Meta offers significant potential in identifying clinical dysbiotic features that can reliably predict human disease, validated comprehensively via reanalysis of individual patient 16S data sets. We leveraged the power of Taxa4Meta's pan-microbiome profiling to generate 16S-based classifiers that exhibited excellent utility for stratification of diarrheal patients with Clostridioides difficile infection, irritable bowel syndrome, or inflammatory bowel diseases, which represent common misdiagnoses and pose significant challenges for clinical management. We believe that Taxa4Meta represents a new "best practices" approach to individual microbiome surveys that can be used to define gut dysbiosis at a population-scale level.

Donor-recipient specificity and age-dependency in fecal microbiota therapy and probiotic resolution of gastrointestinal symptoms

Fecal microbiota transplantation (FMT) has proven to be an effective treatment for recurrent Clostridioides difficile infection (rCDI) in both adult and pediatric patients. However, as microbiome development is a critical factor in children, it remains unclear whether adult fecal donors can provide age-appropriate functional restoration in pediatric patients. To address this issue, we conducted an integrated systems approach and found that concordant donor strain engraftment, along with metabolite restoration, are associated with FMT outcomes in both adult and pediatric rCDI patients. Although functional restoration after FMT is not strain-specific, specialized metabolic functions are retained in pediatric patients when adult fecal donors are used. Furthermore, we demonstrated broad utility of high-resolution variant-calling by linking probiotic-strain engraftment with improved gastrointestinal symptoms in adults with irritable bowel syndrome and in children with autism spectrum disorder. Our findings emphasize the importance of strain-level identification when assessing the efficacy of probiotics and microbiota-based therapeutics.

Exploration of associations among dietary tryptophan, microbiome composition and function, and symptom severity in irritable bowel syndrome

BACKGROUND

Imbalance of the tryptophan (TRP) pathway may influence symptoms among patients with irritable bowel syndrome (IBS). This study explored relationships among different components that contribute to TRP metabolism (dietary intake, stool metabolite levels, predicted microbiome metabolic capability) in females with IBS and healthy controls (HCs). Within the IBS group, we also investigated relationships between TRP metabolic determinants, Bifidobacterium abundance, and symptoms of IBS.

METHODS

Participants with IBS (Rome III) and HCs completed a 28-day diary of gastrointestinal symptoms and a 3-day food record for TRP intake. They provided a stool sample for shotgun metagenomics, 16 S rRNA analyses, and quantitative measurement of TRP by mass spectrometry.

RESULTS

Our cohort included 115 females, 69 with IBS and 46 HCs, with a mean age of 28.5 years (SD 7.4). TRP intake (p = 0.71) and stool TRP level (p = 0.27) did not differ between IBS and HC. Bifidobacterium abundance was lower in the IBS group than in HCs (p = 0.004). Predicted TRP metabolism gene content was higher in IBS than HCs (FDR-corrected q = 0.006), whereas predicted biosynthesis gene content was lower (q = 0.045). Within the IBS group, there was no association between symptom severity and TRP intake or stool TRP, but there was a significant interaction between Bifidobacterium abundance and TRP intake (q = 0.029) in predicting stool character.

CONCLUSIONS

Dietary TRP intake, microbiome composition, and differences in TRP metabolism constitute a complex interplay of factors that could modulate IBS symptom severity.

The role of gut microbial β-glucuronidase in drug disposition and development

Gut microbial β-glucuronidase (gmGUS) is involved in the disposition of many endogenous and exogenous compounds. Preclinical studies have shown that inhibiting gmGUS activity affects drug disposition, resulting in reduced toxicity in the gastrointestinal tract (GIT) and enhanced systemic efficacy. Additionally, manipulating gmGUS activity is expected to be effective in preventing/treating local or systemic diseases. Although results from animal studies are promising, challenges remain in developing drugs by targeting gmGUS. Here, we review the role of gmGUS in host health under physiological and pathological conditions, the impact of gmGUS on the disposition of phenolic compounds, models used to study gmGUS activity, and the perspectives and challenges in developing drugs by targeting gmGUS.

Gut feelings: the microbiota-gut-brain axis on steroids

The intricate connection between central and enteric nervous systems is well established with emerging evidence linking gut microbiota function as a significant new contributor to gut-brain axis signaling. Several microbial signals contribute to altered gut-brain communications, with steroids representing an important biological class that impacts central and enteric nervous system function. Neuroactive steroids contribute pathologically to neurological disorders, including dementia and depression, by modulating the activity of neuroreceptors. However, limited information is available on the influence of neuroactive steroids on the enteric nervous system and gastrointestinal function. In this review, we outline how steroids can modulate enteric nervous system function by focusing on their influence on different receptors that are present in the intestine in health and disease. We also highlight the potential role of the gut microbiota in modulating neuroactive steroid signaling along the gut-brain axis.

Yeast β-glucan reduces obesity-associated Bilophila abundance and modulates bile acid metabolism in healthy and high-fat diet mouse models

Emerging evidence links dietary fiber with altered gut microbiota composition and bile acid signaling in maintaining metabolic health. Yeast β-glucan (Y-BG) is a dietary supplement known for its immunomodulatory effect, yet its impact on the gut microbiota and bile acid composition remains unclear. This study investigated whether dietary forms of Y-BG modulate these gut-derived signals. We performed 4-wk dietary supplementation in healthy mice to evaluate the effects of different fiber composition (soluble vs. particulate Y-BG) and dose (0.1% vs. 2%). We found that 2% particulate Y-BG induced robust gut microbiota community shifts with elevated liver Cyp7a1 mRNA abundance and bile acid synthesis. These diet-induced responses were notably different when compared with the prebiotic inulin, and included a marked reduction in fecal Bilophila abundance which we demonstrated as translatable to obesity in population-scale American Gut and TwinsUK clinical cohorts. This prompted us to test whether 2% Y-BG maintained metabolic health in mice fed 60% HFD over 13 wk. Y-BG consistently altered the gut microbiota composition and reduced Bilophila abundance, with trends observed in improvement of metabolic phenotype. Notably, Y-BG improved insulin sensitization and this was associated with enhanced ileal Glpr1r mRNA accumulation and reduced Bilophila abundance. Collectively, our results demonstrate that Y-BG modulates gut microbiota community composition and bile acid signaling, but the dietary regime needs to be optimized to facilitate clinical improvement in metabolic phenotype in an aggressive high-fat diet animal model.NEW & NOTEWORTHY The study shows that dietary Y-BG supplementation modulated gut microbiota, bile acid metabolism and associated signaling pathways. Y-BG significantly reduced Bilophila abundance which is associated with obesity in human cohorts. Correlation analysis confirmed functional interactions between bile acid composition, gut microbiota, and metabolic phenotype, although clinical benefit did not reach significance in an aggressive obesity model. Gut microbiota and bile acids correlated with metabolic parameters, indicating future potential of dietary Y-BG modulation of metabolic pathways.

Sex-Bias in Irritable Bowel Syndrome: Linking Steroids to the Gut-Brain Axis

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder that is more common in females. Despite its high global incidence, the disease mechanism is still unclear and therapeutic options remain limited. The sexual dimorphism in IBS incidence suggests that sex steroids play a role in disease onset and symptoms severity. This review considers sex steroids and their involvement in IBS symptoms and the underlying disease mechanisms. Estrogens and androgens play important regulatory roles in IBS symptomology, including visceral sensitivity, gut motility and psychological conditions, possibly through modulating the gut-brain axis. Steroids are regulators of hypothalamic-pituitary-adrenal activity and autonomic nervous system function. They also modulate gut microbiota and enteric nervous systems, impacting serotonin and mast cell signaling. Sex steroids also facilitate bidirectional cross-talk between the microbiota and host following bacterial transformation and recycling of steroids by the intestine. The sex-specific interplay between sex steroids and the host provides neuroendocrinology insight into the pathophysiology, epigenetics and treatment of IBS patients.

Methimazole-induced antineutrophil cytoplasmic antibody-associated diffuse alveolar haemorrhage in a Chinese woman with Graves' disease

We report on a case of diffuse alveolar haemorrhage in a Chinese woman due to methimazole-induced antineutrophil cytoplasmic antibodies. A literature search for anti-thyroid drugs associated with antineutrophil cytoplasmic antibody-induced diffuse alveolar haemorrhages is reviewed. Diffuse alveolar haemorrhage is a rare complication of thiourea agents and the treatment often requires corticosteroids or other immunosuppressants, together with withdrawal of the causative agent.

Effect of antibiotics on sputum inflammatory contents in acute exacerbations of bronchiectasis

We studied the changes in sputum neutrophil chemotactic activity (NCA) and elastolytic activity (EA) in acute exacerbations of bronchiectasis before and after treatment with oral antibiotics. Twelve patients who chronically produced sputum were assessed in the stable state, and when they subsequently developed symptoms of acute exacerbations, prior to initiation of antibiotics, during 2 weeks of antibiotics, and at 2 and 6 weeks after stopping antibiotics. NCA was measured using modified Boyden's technique with multiwell chemotaxis chamber, and EA with N-succinyl-trialanine-p-nitroanilide as elastase substrate. All 12 patients had NCA (49.3 +/- 8.69% FMLP response) and EA (50.5 +/- 17.1 mU per 100 microliters) in their sputum in the stable state. At acute exacerbation, there was significant increase in NCA (P < 0.001) and EA (P < 0.05). All responded clinically after 1 week of antibiotics, and this was associated with a decrease in NCA and EA back to the levels in stable state. A further week of antibiotics did not result in further decline of NCA or EA. Three patients had another acute exacerbation clinically between 2-6 weeks after stopping antibiotics and their NCA and EA rose again. In the other nine patients, both NCA and EA at 2 and 6 weeks post-treatment were similar to pre-exacerbation levels. Our findings suggest that short course antibiotics effectively control the upsurge in inflammatory activity in acute exacerbations, but has little effect on chronic airway inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Trends in asthma therapy in Hong Kong, 1987-1992

To audit the clinical practice in drug treatment of bronchial asthma in Hong Kong, two questionnaire surveys were conducted in 1987 and 1992. The questionnaire was adapted from the 1984 European Audit. The response rate was 40% (248 of 615 mailings) in 1987 and 32% (207 of 652 mailings) in 1992. A total of 86% and 87% of responders were general practitioners (GP), respectively, and the others were chest physicians (CP). For treatment of acute severe asthma in adults, parenteral aminophylline was the first drug used by GP in 1987, whereas inhaled beta-agonist was used in 1992. Parenteral steroid was more often used by both GP and CP in 1992. In children, inhaled beta-agonist was always the first choice and parenteral steroid ranked higher in 1992, overtaking parenteral aminophylline. For maintenance therapy of chronic asthma in adults, inhaled beta-agonist ranked first in both surveys. Inhaled steroid has become much more popular with GP, ranking second in 1992, overtaking oral bronchodilators. With CP, inhaled steroid was already ranking second in 1987, and it was used as the first drug, as frequently as inhaled beta-agonist, in 1992. In children, in 1987, inhaled beta-agonist was the first drug of choice, and prophylactic drugs ranked lower than oral bronchodilators with both GP and CP. In 1992, cromoglycate and inhaled steroids were much more often used, so much so that among CP, inhaled steroid ranked first, just ahead of inhaled beta-agonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Multivariate analysis of factors affecting pulmonary function in bronchiectasis

Impaired pulmonary function is of prognostic importance in bronchiectasis. To assess the factors affecting pulmonary function in bronchiectasis, we studied the clinical features, atopic status, bronchial responsiveness, systemic inflammatory indices, and sputum characteristics including volume, purulence, leucocyte count, neutrophil chemotactic activity, elastolytic activity (EA) and bacteriology in 82 Chinese patients. The majority of patients had impaired spirometry with airflow obstruction but normal carbon monoxide diffusing capacity. Multivariate analysis showed that factors significantly associated with worse lung function were: bronchial hyperresponsiveness, concomitant asthma, higher serum globulin, higher peripheral leucocyte count, lower serum albumin, greater sputum volume, diffuse disease and older age. When subjects with clinical asthma were excluded, similar factors were identified, and in addition, longer duration of disease, presence of eosinophils in sputum and higher sputum EA were significantly related to worse spirometry. Most of the identified factors reflect a state of inflammation. Thus the findings suggest that persistent inflammation plays an important role in the deterioration of lung function in bronchiectasis.

An audit of antiasthmatic drug inhalation technique and understanding

Inhaled rather than oral antiasthmatic therapy is accepted as more advantageous but depends on patient technique and understanding. In 74 asthmatic outpatients, technique using metered-dose inhaler (MDI) was poor; in 56 patients inhaling beta-agonist, the mean peak expiratory flow rate (PEFR) increase was only 15 L/min (6%) greater than in 18 controls, p < 0.05, 95% confidence intervals 2-27 L/min or 2-11%. Tilting the head back and actuation "stopping" inspiration produced the least favorable PEFR responses; taken together, regression analysis yielded a statistically significant negative correlation with absolute or percentage PEFR change (R2 = 0.15; p < 0.02). Patients were unclear about which drugs to inhale as required or regularly. Among 19 patients reassessed inhaling beta-agonist, only 8 had baseline PEFR values within 10% of each other during both assessments. In the latter, the mean postinhalation PEFR increase was 36 L/min (or 13%) greater than the corresponding increase (or % change) at first assessment, p = 0.05 (0.08), 95% confidence intervals 0-73 L/min (-2 to 29%). Thus, MDI users should avoid tilting the head back, actuation stopping inhalation, and be more aware of prophylactic (steroid) versus symptomatic (beta-agonist) treatment.

High prevalence of asthma in patients with bronchiectasis in Hong Kong

Eighty five Chinese patients with diffuse or localized bronchiectasis (non-cystic fibrosis) were studied regarding the prevalence of asthma. Twenty three of the 85 had concomitant asthma, diagnosed by history and reversibility on lung function testing either spontaneously or after bronchodilator. None fulfilled the diagnostic criteria of allergic bronchopulmonary aspergillosis (ABPA). Asthma preceded the onset of bronchiectasis in 13 patients and developed after long duration of bronchiectasis in seven, while the temporal onset could not be differentiated in three patients. Patients with both asthma and bronchiectasis had inferior spirometric values, higher prevalence of bronchial hyperresponsiveness to methacholine, higher prevalence of skin atopy, elevated serum immunoglobulin E (IgE), and more sputum eosinophilia, compared with their non-asthmatic counterparts. Possible mechanisms by which asthma and bronchiectasis predispose to each other include asthmatic obstruction contributing to development of bronchiectasis, and sensitization of airways with increased lability due to microbial colonization of the ectatic bronchial tree.

High prevalence of asthma in patients with bronchiectasis in Hong Kong

Eighty five Chinese patients with diffuse or localized bronchiectasis (non-cystic fibrosis) were studied regarding the prevalence of asthma. Twenty three of the 85 had concomitant asthma, diagnosed by history and reversibility on lung function testing either spontaneously or after bronchodilator. None fulfilled the diagnostic criteria of allergic bronchopulmonary aspergillosis (ABPA). Asthma preceded the onset of bronchiectasis in 13 patients and developed after long duration of bronchiectasis in seven, while the temporal onset could not be differentiated in three patients. Patients with both asthma and bronchiectasis had inferior spirometric values, higher prevalence of bronchial hyperresponsiveness to methacholine, higher prevalence of skin atopy, elevated serum immunoglobulin E (IgE), and more sputum eosinophilia, compared with their non-asthmatic counterparts. Possible mechanisms by which asthma and bronchiectasis predispose to each other include asthmatic obstruction contributing to development of bronchiectasis, and sensitization of airways with increased lability due to microbial colonization of the ectatic bronchial tree.

Analysis of factors associated with bronchial hyperreactivity to methacholine in bronchiectasis

Nonspecific bronchial hyperreactivity (BHR) has been reported to occur in patients with bronchiectasis. To evaluate this further, we studied 77 patients with stable bronchiectasis (noncystic fibrosis) with special reference to the prevalence of BHR to methacholine (MCh), and its relation to lung function, sputum characteristics, concommitant asthma, and atopy. The concentration of MCh required to produce a fall of 20% in forced expiratory volume in 1 s (FEV1), PC20, was determined by Wright's nebulization tidal breathing method. BHR defined by a PC20 greater than or equal to 8 mg/ml was found in 21 of 47 (45%) subjects who underwent bronchial challenge. Presence of BHR was positively associated with low baseline spirometric values, diagnosis of asthma, long duration of disease, and elevated total IgE on univariant analysis, and was significantly related to FEV1/forced vital capacity (FVC) ratio and asthma on multiple regression analysis. Ten of the 21 hyperreactive subjects did not have clinical asthma, whereas all 11 of 22 subjects with clinical asthma who underwent bronchial challenge were hyperreactive. Among those with BHR, there was a positive correlation between PC20 and baseline FEV1. When patients were further classified into asthmatic and nonasthmatic subjects, a positive correlation between PC20 and FEV1 was seen only in those without asthma. Frequency of infective episodes and inflammatory score of sputum assessed by average daily volume, purulence, and leukocyte count did not differ significantly in the groups with and without BHR. These results suggest that BHR in patients with bronchiectasis is associated with coexistent asthma and worse spriometric values, and not with the severity of bronchial sepsis.

Rising asthma mortality in young males in Hong Kong, 1976-85

The trend in asthma mortality in Hong Kong was estimated from published statistics for the years 1976-85. To avoid coding errors in death certifications, only asthma deaths in the age group 5-34 years were analysed. Mortality rose annually by an average of 10.5% in male (P less than 0.02), but not female asthmatics. Such an increase was not due to a change in coding as a result of the revision of the International Classification of Diseases in 1979, or an exchange of diagnostic labelling from other respiratory diseases. The exact causes for the increase in asthma mortality have yet to be determined.

Ofloxacin versus co-trimoxazole for prevention of infection in neutropenic patients following cytotoxic chemotherapy

The efficacy of ofloxacin in preventing infection in neutropenic patients following cytotoxic chemotherapy was evaluated and was compared with that of co-trimoxazole. A total of 102 patients with hematological malignancies were randomly selected to receive either co-trimoxazole or ofloxacin. All patients were monitored for compliance, occurrence of infection, and drug-related side effects. A surveillance culture of a rectal swab was performed regularly. A total of 25 of the 52 patients (48%) who received co-trimoxazole and 11 of the 50 patients (22%) who received ofloxacin developed fever during the study period (P less than 0.025). Gram-negative bacteremia occurred in nine patients in the co-trimoxazole group (17%) but in only one patient (2%) in the ofloxacin group (P less than 0.05). No patient in either group had documented gram-positive bacterial or Pneumocystis carinii infection. Poor performance status was the only identifiable factor associated with an increased incidence of bacteremia. The surveillance study showed that significantly fewer bacterial strains were resistant to ofloxacin than to co-trimoxazole and that acquisition of resistance to co-trimoxazole was more commonly observed than was acquisition of resistance to ofloxacin. Significantly more patients had skin rashes following co-trimoxazole than ofloxacin treatment (P less than 0.05). Ofloxacin was superior to co-trimoxazole in preventing infection in this population of neutropenic patients.

The value of routine bronchial aspirate culture at fibreoptic bronchoscopy for the diagnosis of tuberculosis

We review the results of bronchial aspirate culture for mycobacteria sent routinely in a series of 1734 fibreoptic bronchoscopic procedures. The incidence of tuberculosis in the series was 8.3% (144 cases). Of these cases, a positive bronchial aspirate culture was obtained in 119 (82.6%) cases, and it was the exclusive means of diagnosis in 64 (44.4%). In 66% of these cases tuberculosis was not suspected at the time of bronchoscopy. Our results suggest that in an area with a high prevalence of tuberculosis, routine bronchial aspirate culture is a useful adjunct to diagnosis.

High incidence of pulmonary tuberculosis in the non-HIV infected immunocompromised patients in Hong Kong

In areas where tuberculosis is endemic, clinicians managing immunocompromised patients (ICP) are confronted with the possibility of Mycobacterium tuberculosis as a pathogen. To determine the incidence and clinical pattern of, the diagnostic approach to, and potential therapeutic implications of pulmonary tuberculosis in this patient population, we reviewed 62 non-HIV infected ICP in Hong Kong who had bronchoscopy because of pulmonary infiltrates. Pulmonary tuberculosis was the second most common cause after bacterial infections. Clinical and radiographic presentations of 12 patients with tuberculosis were nonspecific. Flexible bronchoscopy for tuberculosis carried a diagnostic sensitivity of 91.7 percent. We conclude that for the non-HIV infected ICP from areas where tuberculosis is endemic: M tuberculosis should be suspected as the pathogen; radiographic findings are diagnostically not helpful; FB is a sensitive diagnostic test for tuberculosis and in smear-negative cases where tuberculosis is suspected, initiation of empiric anti-tuberculosis therapy should be considered while awaiting culture results.

Pattern of anti-asthmatic drug utilization in Hong Kong compared to other parts of the world

Inhaled drugs are now considered first line agents for the treatment of asthma, whereas oral beta-agonists, theophylline and its derivatives have been relegated to a secondary role. To determine whether current prescribing in Hong Kong conforms to these recommendations, we have evaluated anti-asthmatic drug utilization in the territory as reflected by 1984-86 drug sales (courtesy Medical and Health Department, Hong Kong). Sales/prescription statistics were also obtained from corresponding agencies of other governments and from published literature. If appropriate, data for comparison was expressed as defined daily doses (DDDs) per 1000 inhabitants per day. In contrast to the pattern of utilization in several developed nations, in Hong Kong (a) oral anti-asthmatic agents (particularly beta agonists) were more commonly utilized than inhaled drugs, and (b) inhaled therapy mainly consisted of non-selective beta-agonists, steroids being very rare. Further education is required to improve anti-asthmatic drug utilization patterns in the community.

Ofloxacin compared with amoxycillin in treating infective exacerbations in bronchiectasis

Forty-one hospitalized adult patients of bronchiectasis (non-cystic fibrotic) with infective exacerbations were entered into a randomized, double-blind, placebo-controlled study comparing ofloxacin (200 mg tid) and amoxycillin (1 g tid) both orally for ten days. In the ofloxacin group (20 patients), improvement in sputum purulence was excellent in 14, and fair in five patients with one failure. In the amoxycillin group (21 patients), improvement in sputum purulence was excellent in eight, fair in five and poor in eight patients. Mean drug levels on day 5 were 4.1 mg l-1 for serum (2 h post-dosage) and 4.0 mg l-1 for sputum for ofloxacin, and 18.4 mg l-1 for serum and 0.3 mg l-1 for sputum for amoxycillin. Ofloxacin thus yielded higher sputum concentration and appeared to be more effective and also better tolerated than amoxycillin in infective episodes of bronchiectasis.

Lung injury in dimethyl sulfate poisoning

Two manual laborers were exposed to dimethyl sulfate during work and sustained mucosal injury to the eyes and respiratory tract. In one of them, noncardiogenic pulmonary edema occurred and improved with high-dose methylprednisolone. On follow-up for 10 months, this patient developed persistent productive cough with no evidence of bronchiectasis or bronchial hyperreactivity.

Unusual rib destruction in pleuropulmonary tuberculosis

Two cases of pleuropulmonary tuberculosis had local rib destruction simulating malignancy. There was no superficial abscess formation which was the usual clinical feature of rib tuberculosis. Computerized tomography was valuable in demonstrating and assessing the extent of skeletal involvement.

Imipenem/cilastatin as initial therapy for febrile neutropenic patients

Imipenem 2 g daily was administered intravenously to 40 evaluable patients with neutropenia and fever. Twenty-three patients had acute leukaemia and 17 malignant lymphoma. The overall response rate was 70.0%. Of the 14 patients with documented infection, 9 (64.3%) responded. Poorer responses were observed in patients with pneumonia (40%) or pseudomonal infection (50%). The response rate was significantly higher among patients with increasing neutrophil counts during therapy (P less than 0.02). Fungal infection was a common cause of treatment failure. Gastrointestinal side effects and skin rashes were occasionally seen. No patient developed central nervous system toxicity. Imipenem is a practical alternative to antibiotic combinations for management of neutropenic infection. However, careful monitoring is essential in the subgroups of patients with pneumonia or pseudomonal infections, who may require modifications of therapy.

Melioidosis: a serological survey in a tuberculosis sanatorium in Hong Kong

A serological survey of 275 Chinese patients with underlying pulmonary diseases in a tuberculosis sanatorium in Hong Kong showed that 39 (14%) had haemagglutinating antibody (HA) against Pseudomonas pseudomallei in a titre of 1: 80 or above. Only 9 of these 39 patients had travelled to endemic areas, suggesting that at least 30 patients (11%) had been exposed to Ps. pseudomallei locally. Females are affected as often as males, and the seropositive rate is the same whether patients are immunosuppressed or not. Because subclinical melioidosis is prevalent and HA may persist for a long time, even at a high titre, after infection, determination of HA alone cannot differentiate between active melioidosis and its masquerade--active tuberculosis.

Pulmonary function in thalassemia major

Pulmonary function tests were evaluated in 28 Chinese patients with beta-thalassemia major receiving regular transfusions and desferoxamine, and in 34 height-matched normal Chinese children. Comparison of lung function using analysis of covariance with reference to standing height showed that patients with thalassemia had a proportional decrease in forced vital capacity and forced expiratory flow volume in 1 second, whereas their expiratory flow rates, residual volume, and total lung capacity were comparable to those in normal children. The single-breath carbon monoxide diffusion capacity was normal. Our findings suggest that children with thalassemia major have mild restrictive lung disease. The previous controversy regarding the presence of restrictive or obstructive lung disease in patients with thalassemia may be related to the use of inappropriate control values.

Chronic sinopulmonary disease in Chinese patients with obstructive azoospermia

The prevalence of chronic infections of the nasal sinuses and the lung (chronic sinopulmonary disease) was investigated in 33 Chinese patients with obstructive azoospermia who were compared with 32 patients with azoospermia due to failure of the germinal epithelium. Ten out of the group of 33 patients with obstructive azoospermia had congenital absence of the vas and/or epididymis and were excluded from that group. The patients with obstructive azoospermia had normal testis size, normal levels of serum FSH and LH, lower seminal fluid fructose, and a higher incidence of serum sperm agglutinating and immobilizing antibodies when compared with the group with damage to the germinal epithelium. The number of patients with symptoms of chronic sinopulmonary infections were similar in all groups. One patient with obstructive azoospermia had bronchiectasis. All other patients had normal chest x-ray studies. About 40% of the patients in all three groups had abnormal sinus X-rays. However, the nonsmoking patients with obstructive azoospermia had a statistically significant (P less than 0.05) lower mid-expiratory flow rate than the nonsmoking patients with nonobstructive azoospermia. Only three additional patients with obstructive azoospermia had both abnormal sinus x-ray and a reduced mid-expiratory flow rate, suggestive of Young's syndrome. It was concluded that Young's syndrome (sinopulmonary infections associated with acquired obstructive azoospermia) is much less common in Chinese men (four out of 23, 17%) and their sinopulmonary problems are less severe than in Caucasians.

Enzyme-linked immunosorbent assay (ELISA) of antibodies to purified protein derivative (PPD) in the diagnosis of active tuberculosis: evaluation of its potential and limitation in a high prevalence area

Sera from patients with active tuberculosis were assayed for IgG antibodies to purified protein derivative (PPD) by an enzyme-linked immunosorbent assay (ELISA) technique. Eighty seven of the 112 patients (78%) with sputum culture-positive, and 57 of 78 patients (73%) with sputum culture-negative, pulmonary tuberculosis had positive serology. Seventeen of 19 patients (89%) with renal tuberculosis (demonstrable lesion on intravenous pyelography) had antibody to PPD, whereas only 3 of 9 patients (33%) with urinary tuberculosis (positive urine culture only, without abnormality on intravenous pyelography) and 8 of 21 patients (38%) with tuberculous cervical lymphadenitis had positive serology. Seropositivity rate in paediatric patients was also low, only 2 out of 8 patients gave positive serology. Thus, the diagnostic value of this test is limited as a positive result is obtained only when the disease is relatively long-standing or extensive.

5-fluorouracil, adriamycin, and mitomycin-C (FAM) chemotherapy in advanced adenocarcinoma of the lung: comparison of two dosage schedules

Fifty patients with inoperable adenocarcinoma of the lung were randomized in a prospective study to receive either standard doses or high doses of 5-fluorouracil, adriamycin, and mitomycin-C (FAM versus Hi-FAM). The response/stabilization rate was 32% for FAM and 34% for Hi-FAM (P greater than 0.05), and the median survival was 27 weeks for FAM group and 24 weeks for Hi-FAM group (P greater than 0.05). Myelotoxicity was mild in FAM, but moderate to severe in Hi-FAM. It is concluded that Hi-FAM did not yield a higher response rate or median survival compared with FAM, but caused significantly more severe myelotoxicity.

Attenuation of exercise-induced asthma by acupuncture

A prospective randomised single-blind study of the effects of real and sham acupuncture on exercise-induced asthma was conducted in nineteen children. Forced expiratory flow in 1st second (FEV1), forced vital capacity (FVC), and peak expiratory flow rate (PEFR) were measured throughout acupuncture and after treadmill exercise. Neither real nor sham acupuncture affected the basal bronchomotor tone but both, when applied 20 min before exercise, attenuated exercise induced asthma: mean maximum percentage falls in FEV1, FVC, and PEFR were 44.4%, 33.3%, and 49.5% without acupuncture; 23.8%, 15.8%, and 25.9% after real acupuncture; and 32.6%, 26.1%, and 34.3% after sham acupuncture. Real acupuncture provided better protection against exercise-induced asthma than did sham acupuncture (p less than 0.05).

Twice daily administration of beclomethasone dipropionate dry-powder in the management of chronic asthma

In a double-blind cross-over study beclomethasone dipropionate inhaled as a dry-powder in a dose of 400 micrograms twice daily was compared with a conventional aerosol in a dose of 100 micrograms four times daily in 16 outpatients with chronic asthma. Each of the 2 treatments lasted for 4 weeks. There was no significant difference with respect to daily peak expiratory flow rates, symptom scores, bronchodilator usages and other lung function measurements between the 2 treatments. Tetracosactrin tests were within normal limits and no clinical oral candidiasis was observed throughout the study. In conclusion, beclomethasone dipropionate dry-power given twice daily was effective for the control of asthma and could be recommended for patients with poor drug compliance.

No association between HLA antigens and adenocarcinoma of the lung in non-smoking Chinese women in Hong Kong

A high incidence rate of lung cancer with preponderance of adenocarcinoma in non-smokers has been reported in women of southern Chinese ethnic origin. Thirty-three southern Chinese female patients with primary adenocarcinoma of the lung, all lifelong non-smokers, were typed for HLA-A and B antigens to study the possibility of genetically determined susceptibility factors. The antigen frequencies were compared with those of 110 healthy controls. No significant difference in antigen frequencies was found in the patients compared with controls. Studies on other possible factors determining susceptibility to lung cancer in Chinese women are necessary.

A double-blind randomized study comparing ofloxacin and amoxicillin in treating infective episodes in bronchiectasis

32 hospitalized adult patients with infective episodes of bronchiectasis were enrolled in an ongoing double-blind, placebo-controlled study comparing ofloxacin with amoxicillin. They were randomized to receive either 200 mg ofloxacin or 1 g amoxicillin, both t.i.d. orally for ten days. In the ofloxacin group (15 patients), clinical response was excellent (clinical cure) in 11 and fair (clinical improvement or early reinfection) in three patients with one failure. In the amoxicillin group (17 patients), clinical response was excellent in six, fair in five, and poor (treatment failure) in six patients. Ofloxacin levels at 2 h (day 5) were 2.3 to 8.2 mg/l (mean 3.9 mg/l) for serum and 1.3 to 15 mg/l (mean 4.5 mg/l) for sputum. Sputum: serum ratio was 1.2:1. Amoxicillin levels at 2 h were 10 to 40 mg/l (mean 19.9 mg/l) for serum and 0 to 1.5 mg/l (mean 0.3 mg/l) for sputum, with no amoxicillin detected in sputum in 10 of 17 patients. Sputum: serum ratio was 0.02:1. One patient in the ofloxacin group had nausea. In the amoxicillin group, four patients had nausea and stomach pain, one had vertigo and one had transient peripheral eosinophilia. Ofloxacin thus yielded higher sputum concentration and appeared to be more effective and better tolerated than amoxicillin in infective episodes of bronchiectasis.

Complete absence of serum alpha-1-antitrypsin in conjunction with an apparently normal gene structure

A family in which a Pinull allele for alpha-1-antitrypsin (A-1-AT) segregates has been studied in detail. Two homozygous sisters have no detectable A-1-AT in their serum as measured with the most sensitive methods currently available. Both have airways obstruction, and one has bullous emphysema. Heterozygotes for Pinull and the common normal allele PiM1 have half-normal serum concentrations of A-1-AT. A restriction enzyme analysis of chromosomal DNA of the two homozygotes and one heterozygote demonstrated the presence of an apparently complete structural gene for A-1-AT. Thus, the genetic defect in Pinull is not a complete or partial deletion of the structural gene. A base pair change that cannot be detected by the restriction enzymes used here, of course, cannot be excluded. Another possibility is a mutation outside the structural gene that affects the synthesis of the protein.

AIDS in a Hong Kong Chinese

A young Hong Kong Chinese male patient with fever of unknown origin is presented. The diagnosis of acquired immunodeficiency syndrome was made only 5 months after the onset of his illness. The lack of awareness of the syndrome might account for the delay in the diagnosis. The legal attitude towards homosexuality might have an adverse effect on epidemiological studies of AIDS in Hong Kong.

Thymectomy in myasthenia gravis during pregnancy

A 24 year old woman with myasthenia gravis suffered an antepartum exacerbation which failed to respond to increasing dosages of pyridostigmine. Thymectomy performed in the second trimester was followed by clinical improvement and full term vaginal delivery with no puerperal deterioration.

Endobronchial tuberculosis revisited

Analysis was made of 20 patients with endobronchial tuberculosis proven by fiberoptic bronchoscopy and bronchial biopsy. Unlike prechemotherapy reports, the disease affects the older age group and more men. Only one half of the patients had fever, and the characteristic localized wheeze was found in 15 percent of cases. Chest roentgenogram showed typical collapse-consolidation in most cases; however, it was clear in 20 percent of patients. Sputum/smear was negative for AFB in 85 percent of patients. When the gelatinous granulation tissue was not found during bronchoscopy, a diagnosis of bronchogenic carcinoma was made incorrectly in 30 percent of patients. At a mean period of 27 months postchemotherapy, all 12 patients recalled for study developed bronchostenosis proven by bronchoscopy/bronchography except one. Noninvasive methods such as chest roentgenogram and flow-volume loops were insensitive for detection of stenosis. Steroid therapy probably did not influence outcome of tuberculous endobronchitis.

An unusual cause of central cyanosis in a patient with rheumatic heart disease

Images

Selective 5-HT2 receptor blockade in exercise-induced asthma

Seven young extrinsic asthmatics participated in an open, pilot study to determine the protective effect of a selective 5-hydroxytryptamine (5-HT) blocking agent, ketanserin, on exercise induced asthma. Ketanserin in a dose of 10 mg given intravenously 20 min before exercise altered the basal bronchomotor tone in only 1 of 6 subjects and offered partial protection against exercise-induced bronchoconstriction in 1 of 5 asthmatics with no overall effect in the group. All patients experienced sleepiness after administration of ketanserin and one had bradycardia with hypotension. The ineffectiveness of ketanserin suggests indirectly that serotonin has a limited role in the pathogenesis of exercise-induced asthma.

Respiratory problems in myasthenia gravis

We evaluated our experience involving 27 patients with myasthenia gravis with particular reference to the various respiratory problems encountered. These included restriction of ventilation, respiratory tract infections, aspiration due to bulbar weakness, respiratory failure requiring mechanical ventilation, and post-thymectomy pulmonary complications.

Intrapulmonary thymoma: report of two cases

Images