Nosocomial tuberculosis prevention measures among two groups of US hospitals, 1992 to 1996

Incidence of tuberculosis infection among healthcare workers: risk factors and 20-year evolution

OBJECTIVE

To determine the incidence of latent tuberculosis infection (LTBI), and risk factors for tuberculosis skin test (TST) conversion among Healthcare workers (HCWs) during a 20-year follow-up period.

DESIGN

Prospective cohort analysis. Surveillance was conducted from January 1, 1988, to December 31, 2007.

SETTING

600-bed tertiary referral hospital in Barcelona, Spain.

PARTICIPANTS

HCWs in risk for occupational tuberculosis (TB) exposure, with negative baseline TST, direct contact with patients and/or biological samples and at least one follow-up visit with TST.

METHODS

TST is performed in HCWs with no previous history of TB or no previous positive TST. When TST is negative this test is performed once a year in high-risk workers, or at least every 2 years according to the hospital's guidelines. In all cases an interview questionnaire to gather information on possible risk factors was performed.

RESULTS

The study included 614 HCWs, 27% worked in areas of risk for TB exposure. Annual incidence rate had decreased from 46.8 per 100 person-years in 1990 to 1.08 per 100 person-years in 2007. Cumulative incidence was higher in HCWs who work in high-risk areas (p = 0.004) and in time periods from 1990 to 1995, and from 1996 to 2001 (p < 0.0001). Cox regression model showed a hazard ratio of 1.55 (CI 95%; 1.05-2.27) in high-risk workers, adjusted by gender, age and professional status.

CONCLUSIONS

Incidence of LTBI among HCWs is high, although it decreased throughout the follow-up period. It is crucial to maintain surveillance programs in HCWs.

Active tuberculosis among health care workers in Portugal

OBJECTIVE

To determine the incidence of active tuberculosis (TB) in a cohort of health care workers (HCWs).

METHODS

Descriptive study of active TB cases identified in an occupational health screening of 6,112 HCWs between 2005 and 2010. Cases of active TB were defined as those in which Mycobacterium tuberculosis was identified by direct microscopy or culture; those in which there were symptoms or clinical signs of TB and necrotizing granuloma, as detected by histology; and those in which the radiological findings were consistent with active TB.

RESULTS

Among the 6,112 HCWs evaluated, we identified 62 cases of active TB: pulmonary TB (n = 43); pleural TB (n = 15); lymph node TB (n = 2); pericardial TB (n = 1); and cutaneous TB (n = 1). Seven HCWs were asymptomatic at the time of diagnosis. Of the 62 cases of active TB, 48 developed within the first 10 years of occupational exposure in the workplace, 36 of those occurring within the first 5 years. Physicians and nurses accounted for the highest numbers of cases (22 and 21, respectively).

CONCLUSIONS

In HCWs employed in Portugal, the TB burden is high. Physicians and nurses are the HCWs who are at the highest risk of developing active TB. We found the risk of developing this disease to be highest in the first years of exposure, as has been reported in previous studies. In high-incidence countries, TB screening of HCWs is important for controlling the transmission of this disease.

Electronic sensors for assessing interactions between healthcare workers and patients under airborne precautions

Background

Direct observation has been widely used to assess interactions between healthcare workers (HCWs) and patients but is time-consuming and feasible only over short periods. We used a Radio Frequency Identification Device (RFID) system to automatically measure HCW-patient interactions.

Methods

We equipped 50 patient rooms with fixed sensors and 111 HCW volunteers with mobile sensors in two clinical wards of two hospitals. For 3 months, we recorded all interactions between HCWs and 54 patients under airborne precautions for suspected (n = 40) or confirmed (n = 14) tuberculosis. Number and duration of HCW entries into patient rooms were collected daily. Concomitantly, we directly observed room entries and interviewed HCWs to evaluate their self-perception of the number and duration of contacts with tuberculosis patients.

Results

After signal reconstruction, 5490 interactions were recorded between 82 HCWs and 54 tuberculosis patients during 404 days of airborne isolation. Median (interquartile range) interaction duration was 2.1 (0.8–4.4) min overall, 2.3 (0.8–5.0) in the mornings, 1.8 (0.8–3.7) in the afternoons, and 2.0 (0.7–4.3) at night (P<10⁻⁴). Number of interactions/day/HCW was 3.0 (1.0–6.0) and total daily duration was 7.6 (2.4–22.5) min. Durations estimated from 28 direct observations and 26 interviews were not significantly different from those recorded by the network.

Conclusions

The RFID was well accepted by HCWs. This original technique holds promise for accurately and continuously measuring interactions between HCWs and patients, as a less resource-consuming substitute for direct observation. The results could be used to model the transmission of significant pathogens. HCW perceptions of interactions with patients accurately reflected reality.

Health care-associated infection outbreak investigations by the Centers for Disease Control and Prevention, 1946-2005

Since 1946, Centers for Disease Control and Prevention (CDC) personnel have investigated outbreaks of infections and adverse events associated with delivery of health care. CDC Epidemic Intelligence Service officers have led onsite investigations of these outbreaks by systematically applying epidemiology, statistics, and laboratory science. During 1946-2005, CDC Epidemic Intelligence Service officers conducted 531 outbreak investigations in facilities across the United States and abroad. Initially, the majority of outbreaks involved gastrointestinal tract infections; however, in later years, bloodstream, respiratory tract, and surgical wound infections predominated. Among pathogens implicated in CDC outbreak investigations, Staphylococcus aureus, Enterococcus species, Enterobacteriaceae, nonfermentative Gram-negative bacteria, or yeasts predominated, but unusual organisms (e.g., the atypical mycobacteria) were often included. Outbreak types varied and often were linked to transfer of colonized patients or health care personnel between facilities (multihospital outbreaks), national distribution of contaminated products, use of invasive medical devices, or variances in practices and procedures in health care environments (e.g., intensive care units, water reservoirs, or hemodialysis units). Through partnerships with health care facilities and local and state health departments, outbreaks were terminated and lives saved. Data from investigations invariably contributed to CDC-generated guidelines for prevention and control of health care-associated infections.

[A study of tuberculosis infection in workers at a university general hospital: associated factors and evolution in 20 years]

OBJECTIVE

To estimate the prevalence of tuberculous infection (TI) in the health-care workers of a hospital over the course of a 20-year period and analyze the associated risk factors.

SUBJECTS AND METHODS

A cross-sectional, descriptive study of the workers of a general hospital from 1988 until 2007, using a tuberculin test (TT) and questionnaire.

RESULTS

2,179 workers were studied (mean age 32.4 years (SD 8.4). 24.5% worked in areas at risk for tuberculosis (TB). 8.1% (174) were vaccinated with BCG. The prevalence of positive baseline TT was 25.7% (95% confidence interval: 23.8-27.4%). There was a greater percentage of positive TT in the 1988-1992 period (44.2%) and a smaller percentage (15.8%) in the 2003-2007 period (P<.0001). The prevalence of TI was 1.53 times greater in males and 1.89 in those vaccinated with BCG. When compared with resident physicians, the prevalence of TI was greater in the rest of the professional categories, while increasing 1.03 times per year that age increases and 1.05 times per year of professional activity.

CONCLUSIONS

The data provide relevant information about the evolution of TI in hospital professionals over the course of a 20-year period. The prevalence decreased during the study period, probably due to a decrease in the incidence of TB in the reference community and to improved prevention measures and nosocomial control.

Results of five-year systematic screening for latent tuberculosis infection in healthcare workers in Portugal

Introduction

The risk of tuberculosis (TB) in healthcare workers (HCWs) is related to its incidence in the general population, and increased by the specific risk as a professional group. The prevalence of latent tuberculosis infection (LTBI) in HCWs in Portugal using the tuberculin skin test (TST) and the interferon-γ release assays (IGRA) was analyzed over a five-year period.

Methods

A screening programme for LTBI in HCWs was conducted, with clinical evaluations, TST, IGRA, and chest radiography. Putative risk factors for LTBI were assessed by a standardised questionnaire.

Results

Between September 2005 and June 2009, 5,414 HCWs were screened. The prevalence of LTBI was 55.2% and 25.9% using a TST ≥ 10 mm or an IGRA test result (QuantiFERON-TB Gold In-Tube) INF-γ ≥0.35 IU/mL as a criterion for LTBI, respectively. In 53 HCWs active TB was diagnosed. The number of HCWs with newly detected active TB decreased from 19 in the first year to 6 in 2008. Risk assessment was poorly related to TST diameter. However, physicians (1.7%) and nurses (1.0%) had the highest rates of active TB.

Conclusions

LTBI and TB burden among HCWs in Portugal is high. The screening of these professionals to identify HCWs with LTBI is essential in order to offer preventive chemotherapy to those with a high risk of future progression to disease. Systematic screening had a positive impact on the rate of active TB in HCWs either by early case detection or by increasing the awareness of HCWs and therefore the precautions taken by them.

Tuberculosis among health care workers in a Brazilian tertiary hospital emergency unit

The Brazilian emergency system is being reorganized as a hierarchy in the region of Ribeirão Preto, state of São Paulo. We found increased occupational risk for tuberculosis in this region tertiary reference center--a nurse technician (Incidence rate [IR] 526.3/100,000 inhabitants) had a risk of tuberculosis 12.6 (95% confidence interval [CI], 2.57-37.23) greater than the city population (41.8/100,000 inhabitants). The system reorganization will have to make the centers adequate to deal with this problem.

Control and prevention of healthcare-associated tuberculosis: the role of respiratory isolation and personal respiratory protection

Although the prevalence of tuberculosis continues to decline in most developed countries, the risk of healthcare-associated tuberculosis, remains for patients or healthcare staff. Outbreaks of healthcare-associated tuberculosis are usually associated with delays in diagnosis and treatment, or the care of patients in sub-optimal facilities. The control and prevention of tuberculosis in hospitals is best achieved by three approaches, namely administrative (early investigation diagnosis, etc.), engineering (physical facilities e.g. ventilated isolation rooms) and personal respiratory protection (face sealing masks which are filtered). Recent guidelines on the prevention of tuberculosis in healthcare facilities from Europe and the USA have many common themes. In the UK, however, negative pressure isolation rooms are recommended only for patients with suspected multi-drug resistant TB and personal respiratory protection, i.e. filtered masks, are not considered necessary unless multi-drug resistant TB is suspected, or where aerosol-generating procedures are likely. In the US, the standard of care for patients with infectious tuberculosis is a negative pressure ventilated room and the use of personal respiratory protection for all healthcare workers entering the room of a patient with suspected or confirmed tuberculosis. The absence of clinical trials in this area precludes dogmatic recommendations. Nonetheless, observational studies and mathematical modelling suggest that all measures are required for effective prevention. Even when policies and facilities are optimal, there is a need to regularly review and audit these as sometimes compliance is less than optimal. The differences in recommendations may reflect the variations in epidemiology and the greater use of BCG vaccination in the UK compared with the United States. There is a strong argument for advising ventilated facilities and personal respiratory protection for the care of all patients with tuberculosis, as multi-drug tuberculosis may not always be apparent on admission, and these measures minimise transmission of all cases of TB to other patients and healthcare staff.

Comparison of the serological responses to Moraxella catarrhalis immunoglobulin D-binding outer membrane protein and the ubiquitous surface proteins A1 and A2

Moraxella catarrhalis immunoglobulin D-binding protein (MID) is a complex antigen with unique immunoglobulin D (IgD)-binding, adhesion, and hemagglutination properties. Previous studies have shown that antibodies raised against MID764-913 in rabbits inhibited M. catarrhalis adhesion to human alveolar epithelial cells, and immunization with MID764-913 resulted in an increased pulmonary clearance in a murine model. Strong immune responses against MID have also consistently been shown in humans. Here, the MID-specified IgG responses were compared to those of ubiquitous surface proteins A1 and A2 (UspA1/A2) using a series of recombinant fragments that spanned all three proteins. Sera were obtained from young children, aged 6 months to 1 year (n=8) and 2 to 3 years (n=15), and healthy adults (n=16). Acute- and convalescent-phase sera from chronic obstructive pulmonary disease (COPD) patients with M. catarrhalis infective exacerbations (n=23) were also analyzed. Young children, who are at risk of M. catarrhalis infection, had low levels of anti-MID and anti-UspA1/A2 antibodies. Healthy adults and the majority of COPD patients (16/23) had high levels of antibodies directed against, among others, the adhesive domain of MID and the fibronectin- and C3-binding domains of UspA1/A2. Among eight COPD patients in whom a rise in antibody levels could be detected, these functional domains were also the main regions targeted by the antibodies. In addition, human IgG directed against MID was bactericidal and anti-MID antibodies were additive to antibodies targeting UspA1/A2. Hence, the functional domains in these three antigens may have significant potential in a future vaccine against M. catarrhalis.

Nontypeable Haemophilus influenzae adheres to intercellular adhesion molecule 1 (ICAM-1) on respiratory epithelial cells and upregulates ICAM-1 expression

Nontypeable Haemophilus influenzae (NTHI) is an important respiratory pathogen. NTHI initiates infection by adhering to the airway epithelium. Here, we report that NTHI interacts with intracellular adhesion molecule 1 (ICAM-1) expressed by respiratory epithelial cells. A fourfold-higher number of NTHI bacteria adhered to Chinese hamster ovary (CHO) cells transfected with human ICAM-1 (CHO-ICAM-1) than to control CHO cells (P < or = 0.005). Blocking cell surface ICAM-1 with specific antibody reduced the adhesion of NTHI to A549 respiratory epithelial cells by 37% (P = 0.001) and to CHO-ICAM-1 cells by 69% (P = 0.005). Preincubating the bacteria with recombinant ICAM-1 reduced adhesion by 69% (P = 0.003). The adherence to CHO-ICAM-1 cells of NTHI strains deficient in the adhesins P5, P2, HMW1/2, and Hap or expressing a truncated lipooligosaccharide was compared to that of parental strains. Only strain 1128f-, which lacks the outer membrane protein (OMP) P5-homologous adhesin (P5 fimbriae), adhered less well than its parental strain. The numbers of NTHI cells adhering to CHO-ICAM-1 cells were reduced by 67% (P = 0.009) following preincubation with anti-P5 antisera. Furthermore, recombinant ICAM bound to an OMP preparation from strain 1128f+, which expresses P5, but not to that from its P5-deficient mutant, confirming a specific interaction between ICAM-1 and P5 fimbriae. Incubation of respiratory epithelial cells with NTHI increased ICAM-1 expression fourfold (P=0.001). Adhesion of NTHI to the respiratory epithelium, therefore, upregulates the expression of its own receptor. Blocking interactions between NTHI P5 fimbriae and ICAM-1 may reduce respiratory colonization by NTHI and limit the frequency and severity of NTHI infection.

Review of epidemiological studies on the occupational risk of tuberculosis in low-incidence areas

This review summarizes the epidemiological evidence for occupationally acquired tuberculosis and considers the implications for the prevention of tuberculosis. The relevant epidemiological studies were identified on the basis of the Medline data bank, starting with the year 1966. The evaluation of occupational groups with an elevated tuberculosis risk is exclusively based on epidemiologic studies of good or acceptable quality, applying clearly defined criteria of methodological quality. In summary, the available epidemiological evidence suggests that the risk of tuberculosis is elevated in the following occupational groups: hospital employees in wards with tuberculosis patients; nurses in hospitals; nurses attending HIV-positive or drug-addicted patients; pathology and laboratory workers; respiratory therapists and physiotherapists; physicians in internal medicine, anaesthesia, surgery and psychiatry; non-medical hospital personnel in housekeeping and transport work; funeral home employees, and prison employees. However, the epidemiological evidence is limited for all these occupations, with the exception of the nurses, because of the lack of methodologically adequate studies that have got the statistical power to differentiate between specific work tasks. There is a need for large population-based studies with precise definition of exposure, which should include molecular epidemiologic methods in the investigation of occupational risk factors of tuberculosis.

Nosocomial pulmonary infections in HIV-positive patients

PURPOSE OF REVIEW

Nosocomial infections (NI) constitute a significant public health problem and contribute to prolonged hospitalization, additional healthcare costs, and excess morbidity and mortality. Immunocompromised patients, including HIV-infected individuals, are at increased risk for NI, and 15-18.3% of them are represented by lower respiratory tract infections. Nosocomial pulmonary infections (NPI) appear to be more common in patients with acquired immunodeficiency syndrome (AIDS), as a result of the degree of immunosuppression, prior use of antibiotics, and exposure to invasive procedures.

RECENT FINDINGS

This article reviews the epidemiologic and clinical evidences and reports on the occurrence of NPI in HIV-infected inpatients.

SUMMARY

Although underestimated, NI occur commonly in HIV-infected patients, and among them nosocomial pneumonia, including tuberculosis and bacterial pneumonia, are associated with significant morbidity and mortality. The improvement of antiretroviral therapeutic options in developed countries has resulted in a decreased hospitalization rate of HIV-infected individuals. Healthcare delivery in the in- and outpatient setting represents a potential for infections, including lower respiratory tract ones, according to the degree of immunosuppression and the intensity of invasive procedures. To minimize the risk of acquisition of healthcare associated low respiratory tract infections, adherence of healthcare workers to common infection practices, specific respiratory precautions, and early identification of persons who have tuberculosis or are at high risk for active tuberculosis, should be strengthened.

Delays in suspicion and isolation among hospitalized persons with pulmonary tuberculosis at public and private US hospitals during 1996 to 1999

BACKGROUND

While prior studies have shown that public and private hospitals differ in their rates of suspicion and isolation of patients who are at risk for tuberculosis (TB), no study has investigated whether this variation is due to differences in the impact of patient case-mix on hospitals or to variations attributable to specific hospital practice patterns.

OBJECTIVE

To investigate patient-level and hospital-level factors associated with delays in TB suspicion and isolation among inpatients with pulmonary TB disease.

DESIGN

Retrospective cohort study of patients hospitalized with culture-positive pulmonary TB during 1996 to 1999.

SETTING

Patients with culture-proven pulmonary TB treated at three public hospitals (765 patients) and seven not-for-profit private hospitals (172 patients) in Chicago, Los Angeles, and southern Florida that provided care for five or more patients with TB per year during the study period.

MEASUREMENTS

Two-day rates (within 48 h from admission) of acid-fast bacilli (AFB) smear orders and 1-day rates (within 24 h from admission) of TB isolation.

RESULTS

Two-day rates of ordering AFB smears were > 80% at three public and two private hospitals vs 65 to 75% at five private hospitals. One-day rates of TB isolation at the three public hospitals were 64%, 79%, and 86%, respectively, vs 39 to 58% at the seven private hospitals. Delays of > 2 days in ordering AFB smears were associated with patient-level factors: absence of cough (adjusted odds ratio [AOR], 6.02; 95% confidence interval [CI], 3.82 to 9.52), cavitary lung lesion (AOR, 5.17; 95% CI, 1.98 to 13.50), night sweats (AOR, 3.38; 95% CI, 1.90 to 5.99), chills (AOR, 1.70; 95% CI, 1.01 to 2.88), and female gender (AOR, 1.66; 95% CI, 1.06 to 2.60). Delays of > 1 day in ordering pulmonary isolation were associated with patient-level factors: absence of cough (AOR, 3.40; 95% CI, 2.31 to 5.03), cavitary lung lesion (AOR, 2.66; 95% CI, 1.57 to 4.50), night sweats (AOR, 1.98; 95% CI, 1.35 to 2.92), and history of noninjecting drug use (AOR, 1.86; 95% CI, 1.16 to 2.99) and one hospital-level factor: receiving care at a nonpublic hospital. Even after adjustment for patient-level factors, TB patients at private hospitals were half as likely as those at public hospitals to be placed in pulmonary isolation (AOR, 0.47; 95% CI, 0.30 to 0.72), while odds of suspecting TB in these same patients were similar at both hospitals.

CONCLUSION

Private hospitals should order TB isolation for all patients for whom AFB smears are ordered, a policy that has been instituted previously at public hospitals in our study.

Factors influencing health care workers' adherence to work site tuberculosis screening and treatment policies

BACKGROUND

Despite the known risk of tuberculosis (TB) to health care workers (HCWs), research suggests that many are not fully adherent with local TB infection control policies. The objective of this exploratory study was to identify factors influencing HCWs' adherence to policies for routine tuberculin skin tests (TSTs) and treatment of latent TB infection (LTBI).

METHODS

Sixteen focus groups were conducted with clinical and nonclinical staff at 2 hospitals and 2 health departments. Participants were segmented by adherence to TST or LTBI treatment policies. In-depth, qualitative analysis was conducted to identify facilitators and barriers to adherence.

RESULTS

Among all focus groups, common themes included the perception that the TST was mandatory, the belief that conducting TSTs at the work site facilitated adherence, and a general misunderstanding about TB epidemiology and pathogenesis. Adherent groups more commonly mentioned facilitators, such as the perception that periodic tuberculin skin testing was protective and the employee health (EH) provision of support services. Barriers, such as the logistic difficulty in obtaining the TST, the perception that LTBI treatment was harmful, and a distrust of EH, emerged consistently in nonadherent groups.

CONCLUSIONS

This information may be used to develop more effective interventions for promoting HCW adherence to TB prevention policies. Informed efforts can be implemented in coordination with reevaluations of infection control and EH programs that may be prompted by the publication of the revised TB infection control guidelines issued by the Centers for Disease Control and Prevention in 2005.

Chlamydia pneumoniae activates epithelial cell proliferation via NF-kappaB and the glucocorticoid receptor

Chlamydia pneumoniae is an obligate intracellular eubacterium and a common cause of acute and chronic respiratory tract infections. This study was designed to show the effect of C. pneumoniae on transcription factor activation in epithelial cells. The activation of transcription factors by C. pneumoniae was determined in human epithelial cell lines (HL and Calu3) by electrophoretic DNA mobility shift assay, Western blotting, and luciferase reporter gene assay. The activation of transcription factors was further confirmed by immunostaining of C. pneumoniae-infected HL cells and mock-infected controls. The effect of transcription factors on C. pneumoniae-induced host cell proliferation was assessed by [(3)H]thymidine incorporation and direct cell counting in the presence and absence of antisense oligonucleotides targeting transcription factors or the glucocorticoid receptor (GR) antagonist RU486. The activation of the GR, CCAAT-enhancer binding protein (C/EBP), and NF-kappaB was induced within 1 to 6 h by C. pneumoniae. While the interleukin-6 promoter was not activated by C. pneumoniae, the GR-driven p21((Waf1/Cip1)) promoter was increased 2.5- to 3-fold over controls 24 h after infection. C. pneumoniae dose-dependently increased the DNA synthesis of the host cells 2.5- to 2.9-fold, which was partly inhibited either by RU486 or by NF-kappaB antisense oligonucleotides. Furthermore, we provide evidence that heat-inactivated C. pneumoniae does not cause a significant increase in cell proliferation. Our results demonstrate that C. pneumoniae activates C/EBP-beta, NF-kappaB, and the GR in infected cells. However, only NF-kappaB and the GR were involved in C. pneumoniae-induced proliferation of epithelial cells.

Randomized, double-blind study of prulifloxacin versus ciprofloxacin in patients with acute exacerbations of chronic bronchitis

BACKGROUND

Recently the role of bacteria in acute exacerbations of chronic bronchitis (AECB) as well as antibiotic treatment with selected drugs, especially fluoroquinolones, have been better defined.

OBJECTIVE

To assess the efficacy and safety in patients with AECB of prulifloxacin in comparison with ciprofloxacin.

METHODS

AECB was defined according to the guidelines for the evaluation of new anti-infective drugs for the treatment of respiratory tract infections (1992). 235 patients took part in the trial; 117 (88 males and 29 females, mean age 64.8 years) received 600 mg prulifloxacin once daily and 118 (91 males and 27 females, mean age 64.5 years) 500 mg ciprofloxacin twice a day, for a duration of 10 days. The study design was randomized, multicenter, double-blind, double-dummy. Efficacy evaluations were performed by comparing pretreatment and posttreatment assessments. The clinical response was determined by 4-point rating scores on cough, dyspnea, and expectoration (volume and appearance). The microbiological response was assessed on sputum specimen.

RESULTS

Clinical success was observed in 84.7 and 85% of patients in the prulifloxacin and ciprofloxacin groups, respectively. The 95% confidence interval proved the equivalence of treatments. Both drugs successfully eradicated the most commonly isolated strains, including Haemophilus influenzae, Streptococcus pneumoniae, Klebsiella pneumoniae and Pseudomonas aeruginosa. Both treatments were well tolerated. Adverse drug reactions were always of mild or moderate intensity.

CONCLUSION

The study showed that a 10-day course of prulifloxacin is as effective and safe as ciprofloxacin in the treatment of patients with AECB.

Adaptive immunity to nontypeable Haemophilus influenzae

Nontypeable Haemophilus influenzae (NTHi) colonizes the upper respiratory tract of most healthy people and is also a major cause of infection in chronic obstructive lung disease. The immune response to this bacterium has not been well characterized. We tested the hypothesis that recurrent airway infection with NTHi may be associated with nonclearing adaptive immunity. Study subjects were healthy control subjects and patients with idiopathic bronchiectasis who had severe chronic infection with H. influenzae. We established that all subjects in both groups had detectable antibody to NTHi, suggesting that most normal people have developed an adaptive immune response. To characterize the nature of the immune response, we measured antigen-specific production of T helper cell cytokines and CD40 ligand by flow cytometry and immunoglobulin subclass levels in peripheral blood. We found that normal control subjects made Th1 response to NTHi with distinct CD40 ligand production. In contrast, subjects with bronchiectasis had predominant production of Th2 cytokines, decreased expression of CD40 ligand, and different immunoglobulin G subclass production. Therefore, chronic infection with NTHi in bronchiectasis is associated with a change in adaptive immunity that may be important in the pathogenesis of bronchial infection.

Respiratory viruses in exacerbations of chronic obstructive pulmonary disease requiring hospitalisation: a case-control study

BACKGROUND

Acute exacerbations of chronic obstructive pulmonary disease (AE-COPD) are a common cause of hospital admission. Many exacerbations are believed to be due to upper and/or lower respiratory tract viral infections, but the incidence of these infections in patients with COPD is still undetermined.

METHODS

Respiratory syncytial virus (RSV), influenza A and B, parainfluenza 3, and picornaviruses were detected by nested reverse transcription polymerase chain reaction (RT-PCR) in upper (nasal lavage) and lower respiratory tract specimens (induced sputum). In a 2:1 case-control set up, 85 hospitalised patients with AE-COPD and 42 patients with stable COPD admitted for other medical reasons were studied.

RESULTS

Respiratory viruses were found more often in sputum and nasal lavage of patients with AE-COPD (48/85, 56%) than in patients with stable COPD (8/42, 19%, p<0.01). The most common viruses were picornaviruses (21/59, 36%), influenza A (15/59, 25%), and RSV (13/59, 22%). When specimens were analysed separately, this difference was seen in induced sputum (exacerbation 40/85 (47%) v stable 4/42 (10%), p<0.01) but was not significant in nasal lavage (exacerbation 26/85 (31%) v stable 7/42 (17%), p=0.14). In patients with AE-COPD, fever was more frequent in those in whom viruses were detected (12/48, 25%) than in those in whom viruses were not detected (2/37, 5%, p=0.03).

CONCLUSION

Viral respiratory pathogens are found more often in respiratory specimens of hospitalised patients with AE-COPD than in control patients. Induced sputum detects respiratory viruses more frequently than nasal lavage in these patients. These data indicate that nasal lavage probably has no additional diagnostic value to induced sputum in cross-sectional studies on hospitalised patients with AE-COPD and that the role of viral infection in these patients is still underestimated.

Delays in tuberculosis isolation and suspicion among persons hospitalized with HIV-related pneumonia

BACKGROUND

Despite awareness of HIV-related tuberculosis (TB), nosocomial outbreaks of multidrug-resistant TB among HIV-infected individuals occur.

OBJECTIVE

To investigate delays in TB isolation and suspicion among HIV-infected inpatients discharged with TB or Pneumocystis carinii pneumonia (PCP), common HIV-related pneumonias.

DESIGN

Cohort study during 1995 to 1997.

SETTING

For PCP, 1,227 persons who received care at 44 New York City, Chicago, and Los Angeles hospitals. For TB, 89 patients who received care at five Chicago hospitals.

MEASUREMENTS

Two-day rates of TB isolation/suspicion.

RESULTS

For HIV-related PCP, Los Angeles hospitals had the lowest 2-day rates of isolation/suspicion of TB (24.3%/26.6% vs 65.5%/66.4% for New York City and 62.8%/58.3% for Chicago, respectively; p < 0.001 for overall comparison by chi(2) test for each outcome measure). Within cities, hospital isolation/suspicion rates varied from < 35 to > 70% (p < 0.001 for interhospital comparisons in each city). The Chicago hospital with a nosocomial outbreak of multidrug-resistant TB from 1994 to 1995 isolated 60% of HIV-infected individuals who were discharged with a diagnosis of HIV-related TB and 52% discharged with HIV-related PCP, rates that were among the lowest of all Chicago hospitals in both data sets.

CONCLUSION

Low 2-day rates of TB isolation/suspicion among HIV-related PCP patients were frequent. One Chicago hospital with low 2-day rates of TB isolation/suspicion among persons with HIV-related PCP also had low 2-day rates of isolation/suspicion among confirmed TB patients. That hospital experienced a nosocomial multidrug-resistant TB outbreak. Educational efforts on the benefits of early TB suspicion/isolation among HIV-infected pneumonia patients are needed.