Effect of azithromycin maintenance treatment on infectious exacerbations among patients with non-cystic fibrosis bronchiectasis: the BAT randomized controlled trial

IMPORTANCE

Macrolide antibiotics have been shown beneficial in cystic fibrosis (CF) and diffuse panbronchiolitis, and earlier findings also suggest a benefit in non-CF bronchiectasis.

OBJECTIVE

To determine the efficacy of macrolide maintenance treatment for adults with non-CF bronchiectasis.

DESIGN, SETTING, AND PARTICIPANTS

The BAT (Bronchiectasis and Long-term Azithromycin Treatment) study, a randomized, double-blind, placebo-controlled trial conducted between April 2008 and September 2010 in 14 hospitals in The Netherlands among 83 outpatients with non-CF bronchiectasis and 3 or more lower respiratory tract infections in the preceding year.

INTERVENTIONS

Azithromycin (250 mg daily) or placebo for 12 months.

MAIN OUTCOME MEASURES

Number of infectious exacerbations during 12 months of treatment. Secondary end points included lung function, sputum bacteriology, inflammatory markers, adverse effects, symptom scores, and quality of life.

RESULTS

Forty-three participants (52%) received azithromycin and 40 (48%) received placebo and were included in the modified intention-to-treat analysis. At end of study, the median number of exacerbations in the azithromycin group was 0 (interquartile range [IQR], 0-1), compared with 2 (IQR, 1-3) in the placebo group (P < .001). Thirty-two (80%) placebo-treated vs 20 (46%) azithromycin-treated individuals had at least 1 exacerbation (hazard ratio, 0.29 [95% CI, 0.16-0.51]). In a mixed-model analysis, change in forced expiratory volume in the first second of expiration (percent of predicted) over time differed between groups (F1,78.8 = 4.085, P = .047), with an increase of 1.03% per 3 months in the azithromycin group and a decrease of 0.10% per 3 months in the placebo group. Gastrointestinal adverse effects occurred in 40% of patients in the azithromycin group and in 5% in the placebo group (relative risk, 7.44 [95% CI, 0.97-56.88] for abdominal pain and 8.36 [95% CI, 1.10-63.15] for diarrhea) but without need for discontinuation of study treatment. A macrolide resistance rate of 88% was noted in azithromycin-treated individuals, compared with 26% in the placebo group.

CONCLUSIONS AND RELEVANCE

Among adults with non-CF bronchiectasis, the daily use of azithromycin for 12 months compared with placebo resulted in a lower rate of infectious exacerbations. This could result in better quality of life and might influence survival, although effects on antibiotic resistance need to be considered.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00415350.

Diagnosis of conjunctivitis in primary care: comparison of two different culture procedures

BACKGROUND

In general practice, infectious conjunctivitis is a common and mostly (64%) self-limiting disorder. In case of an aberrant course or severe symptoms, a general practitioner may take a culture. Direct inoculation is considered the reference standard, but usually a swab is sent to a laboratory.

OBJECTIVES

To compare the diagnostic performance of the swab, transported by surface mail with direct inoculation.

METHODS

19 general practitioners took two samples of the conjunctiva from 88 patients with symptoms suggestive of infectious conjunctivitis by rolling a cotton swab across the conjunctiva of the lower fornix. One swab was used to inoculate three agar plates directly, while the other was sent in a Stuart medium to the laboratory and inoculated at the time of arrival. The numbers of positive cultures of both methods were compared.

RESULTS

A pathogen was found in 31 of 88 samples (35% (95% CI 26 to 46)). Surprisingly, the number of positive cultures was higher for the Stuart medium (27/88) than for direct inoculation (23/88). The difference was 4.5% (90% CI 0 to 12, p = 0.388; one-sided McNemar test for paired proportions). In five of the 19 samples that were positive in both tests, the cultured pathogens were different.

CONCLUSIONS

The Stuart medium detected more bacteria than direct inoculation. The lower 90% CI, testing non-inferiority at p = 0.05, indicates that it is unlikely that the Stuart medium misses any positive cultures compared with direct inoculation.

A multi-center blinded study on the efficiency of phenotypic screening methods to detect glycopeptide intermediately susceptible Staphylococcus aureus (GISA) and heterogeneous GISA (h-GISA)

BACKGROUND

To determine the true incidence of hGISA/GISA and its consequent clinical impact, methods must be defined that will reliably and reproducibly discriminate these resistant phenotypes from vancomycin susceptible S. aureus (VSSA).

METHODS

This study assessed and compared the ability of eight Dutch laboratories under blinded conditions to discriminate VSSA from hGISA/GISA phenotypes and the intra- and inter-laboratory reproducibility of agar screening plates and the Etest method. A total of 25 blinded and unique strains (10 VSSA, 9 hGISA and 6 GISA) were categorized by the PAP-AUC method and PFGE typed to eliminate clonal duplication. All strains were deliberately added in quadruplets to evaluate intra-laboratory variability and reproducibility of the methods. Strains were tested using three agar screening methods, Brain Heart Infusion agar (BHI) + 6 microg/ml vancomycin, Mueller Hinton agar (MH) + 5 microg/ml vancomycin and MH + 5 microg/ml teicoplanin) and the Etest macromethod using a 2 McFarland inoculum.

RESULTS AND DISCUSSION

The ability to detect the hGISA/GISA phenotypes varied significantly between methods and phenotypes. BHI vancomycin and MH vancomycin agar screens lacked the ability to detect hGISA. The MH teicoplanin agar screen was more sensitive but still inferior to Etest that had a sensitivity of 98.5% and 99.5%, for hGISA and GISA, respectively. Intra- and inter-laboratory reproducibility varied between methods with poorest performance seen with BHI vancomycin.

CONCLUSION

This is the first multi-center blinded study to be undertaken evaluating various methods to detect GISA and hGISA. These data showed that the ability of clinical laboratories to detect GISA and hGISA varied considerably, and that screening plates with vancomycin have a poor performance in detecting hGISA.

The treatment of acute infectious conjunctivitis with fusidic acid: a randomised controlled trial

BACKGROUND

Acute infectious conjunctivitis is a common disorder in primary care. Despite a lack of evidence regarding the effectiveness of topical antibiotics for the treatment of acute infectious conjunctivitis, most patients presenting in primary care with the condition receive topical antibiotics. In The Netherlands, fusidic acid is most frequently prescribed.

AIM

To assess the effectiveness of fusidic acid gel compared to placebo for acute infectious conjunctivitis.

DESIGN

Double-blind randomised placebo-controlled trial.

SETTING

Twenty-five Dutch primary care centres.

METHOD

Adults presenting with a red eye and either (muco)purulent discharge or glued eyelid(s) were allocated to either one drop of fusidic acid gel 1% or placebo, four times daily during one week. The main outcome measure was the difference in recovery rates at 7 days. Secondary outcome measures were difference in bacterial eradication rates, a survival time analysis of the duration of symptoms, and the difference in recovery rates in culture-positive and culture-negative patients.

RESULTS

One hundred and eighty-one patients were randomised and 163 patients were analysed. Forty-five of the 73 patients in the treatment and 53 of the 90 patients in the placebo group recovered (adjusted risk difference = 5.3% [95% confidence interval {CI} = -11 to 18]). There was no difference between the median duration of symptoms in the two groups. At baseline, the prevalence of a positive bacterial culture was 32% (58/181). The bacterial eradication rate was 76% in the treatment and 41% in the placebo group (risk difference = 35% [95% CI = 9.3 to 60.4]). In culture positive patients, the treatment effect tended to be strong (adjusted risk difference = 23% [95% CI = -6 to 42]).

CONCLUSION

At 7 days, cure rates in the fusidic acid gel and placebo group were similar, but the confidence interval was too wide to clearly demonstrate their equivalence. These findings do not support the current prescription practices of fusidic acid by GPs.

Predicting bacterial cause in infectious conjunctivitis: cohort study on informativeness of combinations of signs and symptoms

OBJECTIVE

To find an efficient set of diagnostic indicators that are optimally informative in the diagnosis of a bacterial origin of acute infectious conjunctivitis.

DESIGN

Cohort study involving consecutive patients. Results of index tests and reference standard were collected independently from each other.

SETTING

25 Dutch health centres.

PARTICIPANTS

184 adults presenting with a red eye and either (muco)purulent discharge or glued eyelid(s), not wearing contact lenses.

MAIN OUTCOME MEASURES

Probability of a positive bacterial culture, given different combinations of index test results; area under receiver operating characteristics curve.

RESULTS

Logistic regression analysis showed optimal diagnostic discrimination for the combination of early morning glued eye(s), itch, and a history of conjunctivitis. The first of these indicators increased the likelihood of a bacterial cause, whereas the other two decreased it. The area under the receiver operating characteristics curve for this combination of symptoms was 0.74 (95% confidence interval 0.63 to 0.80). The overall prevalence of bacterial involvement of 32% could be lowered to 4% or raised to 77%, depending on the pattern of index test results.

CONCLUSION

A bacterial origin of complaints indicative of acute infectious conjunctivitis can be made much more likely or unlikely by the answers to three simple questions posed during clinical history taking (possibly by telephone). These results may have consequences for more targeted prescription of ocular antibiotics.

Performance of phenotypic and genotypic methods to determine the clinical relevance of serial blood isolates of staphylococcus epidermidis in patients with septicemia

Five typing methods, including biotyping (API ID32; BioMérieux, Marcy l'Etoile, France), quantitative antibiogram typing based on actual zone sizes, plasmid typing, randomly amplified polymorphic DNA (RAPD) analysis (with primer M13 and primer set ERIC-2-1026), and pulsed-field gel electrophoresis (PFGE), were compared with a previously performed method of DNA fingerprinting by AFLP (amplified fragment length polymorphism analysis) for their performance in the typing of blood isolates of Staphylococcus epidermidis. Sixteen epidemiologically unrelated strains and 11 sets of four blood culture isolates from 11 patients with septicemia were used. The stabilities and reproducibilities of the patterns, the discriminatory capacities of the methods, and the ability to apply the methods to blood culture isolates were used as performance criteria. All strains tested were typeable by each method, and the patterns were stable and reproducible. The numbers of different types within the collection of 16 epidemiologically different isolates were 5 by biotyping, 14 by antibiogram typing, 4 by plasmid typing, 9 by the RAPD assay (combination of results with primer M13 and primer set ERIC-2-1026), and 16 by PFGE. Within the 11 sets of four blood culture isolates the types found by quantitative antibiogram typing, plasmid typing, and PFGE were unique for each set, whereas by biotyping and RAPD analysis some types were observed in more than one set. The results of biotyping did not correspond with the results of the other methods or the results of AFLP. For 6 of the 11 sets, the results of all methods except those of biotyping corresponded completely. Quantitative antibiogram typing, PFGE, and AFLP proved to be the most accurate of the six typing methods tested.

Biofilm production by Staphylococcus epidermidis isolates associated with catheter related bacteremia

The mean biofilm production of 22 Staphylococcus epidermidis isolates associated with catheter related bacteremia was significantly higher than that of 32 nose isolates from healthy individuals. This difference was due to seven catheter related isolates. These findings do not show a clear association between biofilm production and virulence.

Changing susceptibilities of coagulase-negative staphylococci to teicoplanin in a teaching hospital

The susceptibility of two collections of coagulase-negative staphylococci (CNS) isolated from clinical specimens for teicoplanin and vancomycin were compared. They comprised 91 and 101 isolates, collected in 1985 and 1994 respectively, from different departments of a teaching hospital. MICs of vancomycin and teicoplanin were determined by a modified Etest method. Additionally, a disc diffusion test was performed for teicoplanin. All isolates were susceptible to vancomycin (MIC < or = 4 mg/L). Two of the 91 isolates collected in 1985 were intermediate to teicoplanin (MIC between 8 and 32 mg/L), whereas in 1994 the number of intermediate isolates was 20 out of 101 (P < 0.01). The correlation between MICs, as determined by the modified Etest assay, and disc diffusion zones was poor (r = -0.35). Results show that resistance to teicoplanin in CNS has increased in the study hospital over a period of 9 years. This increase is likely to be correlated with the introduction of teicoplanin. Furthermore, a disc diffusion method does not appear to be the first method of choice for detection of strains of CNS with diminished susceptibility to teicoplanin.

AFLP typing of Staphylococcus epidermidis in multiple sequential blood cultures

AFLP is a novel high-resolution PCR-based DNA fingerprinting method generating complex banding patterns that can be used for comparative analysis. In the present study, the applicability of AFLP in fingerprinting Staphylococcus epidermidis isolates was investigated. The criteria considered were stability of patterns, reproducibility, discriminatory capacity and consistency with epidemiological context. Repeated testing of strains and investigation of subcultures showed that AFLP patterns were reproducible and stable with an intrastrain similarity of S > or = 94% as determined by analysis of digitized patterns. Fifteen unrelated strains were heterogeneous, with a level ranging from 78-93%. The applicability of AFLP in epidemiological studies of S. epidermidis was tested on 11 sets of four blood isolates each, from 11 patients with suspected septicaemia. Nine sets had indistinguishable or highly similar AFLP patterns for each isolate per set, while two sets had heterogeneous patterns. These results show that AFLP has high discriminatory power for strain identification in S. epidermidis.

Identification of multiresistant Staphylococcus epidermidis in neonates of a secondary care hospital using pulsed field gel electrophoresis and quantitative antibiogram typing

AIMS

To determine the diversity of types of Staphylococcus epidermidis in a neonatal care unit of a secondary care hospital in the Netherlands.

METHODS

In a prospective study, specimens from nose, ear, axilla, umbilicus, and groin were taken from patients twice a week during a period of up to two weeks. All isolates were typed by both pulsed field gel electrophoresis (PFGE) and antibiogram analysis.

RESULTS

Fifty three S epidermidis isolates from 15 of 24 patients were obtained in one to four surveys. Fourteen isolates from six patients had a common PFGE pattern and were of one multiresistant antibiogram type. The remaining 39 isolates were allocated to 24 sporadic PFGE types and were more susceptible to antibiotics. Colonisation with the multiresistant strain correlated with a long period of stay and with the use of specific antibiotics. The multiresistant isolates were related closely to isolates of S epidermidis found in a recent study in a teaching hospital in the vicinity of the secondary care hospital.

CONCLUSION

Repeated sampling and the use of two typing methods allowed the identification of two closely related multiresistant S epidermidis strains in two hospitals in the same area.

Multiresistant Staphylococcus epidermidis in a neonatal care unit

OBJECTIVE: To study the presence and diversity of types of Staphylococcus epidermidis in the neonatal intensive care unit of a university hospital. METHODS: During a period of 6 weeks, samples were taken from nose, external auditory canal, axilla, groin and umbilicus from consecutively admitted patients. Patients were sampled two times a week for up to 2 weeks. Isolates of S. epidermidis were characterized by antibiogram, plasmid pattern and biotype. RESULTS: Fifteen patients were included. Each patient was sampled in one to four successive surveys, depending on the admission period. A total of 128 isolates of S. epidermidis were obtained and allocated to seven antibiogram types, 36 plasmid types and 14 biotypes. One plasmid type found in 58 isolates (six patients) corresponded with one multiresistant antibiogram type. The number of isolates with these characteristics increased per neonate from the first survey to the fourth. Nineteen isolates from four patients were allocated to a second plasmid type and were of a common antibiogram type. The remaining 34 plasmid types were sporadic. No clear correspondence of biotypes with antibiogram or plasmid types was found. CONCLUSIONS: The present study revealed the increase in colonization of a multiresistant type of S. epidermidis in the compromised patients during admission to the ward. Further studies have to assess whether this type remains persistent in the ward.

Susceptibility of Streptococcus pyogenes to azithromycin, clarithromycin, erythromycin and roxithromycin in vitro

The susceptibility of 180 clinical isolates of Streptococcus pyrogenes from six regions of The Netherlands to the macrolide antibiotics azithromycin, clarithromycin, erythromycin and roxithromycin was analysed. The results of a microbroth MIC method, the E-test method and a disk diffusion assay were compared, and the MBC determined. In addition, the susceptibility to erythromycin of 436 clinical isolates of S. pyogenes from the Leiden region was determined. The microbroth MIC90s of azithromycin, clarithromycin, erythromycin and roxithromycin for group A streptococci were < or = 0.5 mg/L. Erythromycin had the lowest MIC90 (0.09 mg/L). The MIC data obtained with the E-test method suggested that clarithromycin and erythromycin had slightly higher anti-streptococcal activity than azithromycin and roxithromycin in vitro. MICs obtained with the E-test were lower than those found with the microbroth method. Only minor discrepancies were observed among the three methods. The MBC50 for both clarithromycin and erythromycin was 0.75 mg/L and 5.0 mg/L for azithromycin and roxithromycin. None of the 180 strains and two of the collection of 436 strains (0.5%) were resistant to erythromycin and the other macrolides tested; MICs ranged from 1 to 16 mg/L. The erythromycin-resistant strains showed an inducible type of macrolide-lincosamide-streptogramin B (MLS) resistance.