Antibiotic treatment of Haemophilus influenzae and Haemophilus parainfluenzae infections in patients with cystic fibrosis

Oral antimicrobial use in outpatient cystic fibrosis pulmonary exacerbation management: a single-center experience

INTRODUCTION

Cystic fibrosis (CF) pulmonary disease is characterized by intermittent episodes of acute lung symptoms known as 'pulmonary exacerbations'. While exacerbations are classically treated with parenteral antimicrobials, oral antibiotics are often used in 'mild' cases.

OBJECTIVES

We determined how often management progressed to intravenous (IV) therapy. We also examined multiple courses of oral antimicrobials within one exacerbation, and identified patient factors associated with unsuccessful treatment.

METHODS

We performed a retrospective chart audit of oral antibiotic use in CF patients, from March 2009 through March 2010, for 'mild' CF exacerbations.

RESULTS

Administration of a single vs multiple courses of oral antibiotics for treatment of 'mild' CF exacerbation avoided progression to IV therapy 79.8% and 50.0% of the time, respectively. Overall, oral antibiotics circumvented the need for IV therapy 73.8% of the time. Using multi-variant analysis, we found multiple patient characteristics to be independent risk factors for oral antibiotic failure including a history of pseudomonas infection [odds ratio (OR) 2.13, confidence interval (CI) 1.29-3.54], CF-related diabetes (OR 1.85, CI 1.00-3.41), allergic Bronchopulmonary aspergillosis (OR 3.81, CI 1.38-10.56), low socioeconomic status (OR 1.67, CI 1.04-2.67), and calculated baseline forced expiratory volume in 1 s (FEV1) < 75% of predicted prior to an acute exacerbation (OR 1.93, CI 1.20-3.08). Decline in FEV1 > 10%, weight for age, body mass index, distance from the CF center and gender were not significant.

CONCLUSION

Our observations suggest that one course of oral antimicrobials is frequently effective in outpatient CF pulmonary exacerbations but exacerbations requiring more than one course of oral antibiotics are likely to require IV therapy.

Clinical significance of microbial infection and adaptation in cystic fibrosis

A select group of microorganisms inhabit the airways of individuals with cystic fibrosis. Once established within the pulmonary environment in these patients, many of these microbes adapt by altering aspects of their structure and physiology. Some of these microbes and adaptations are associated with more rapid deterioration in lung function and overall clinical status, whereas others appear to have little effect. Here we review current evidence supporting or refuting a role for the different microbes and their adaptations in contributing to poor clinical outcomes in cystic fibrosis.

Randomised trial of pivampicillin plus pivmecillinam vs. pivampicillin in children and young adults with chronic obstructive pulmonary disease and infection with Haemophilus influenzae

A prospective, randomised, single-blind comparative trial was carried out to determine whether double beta-lactam treatment with pivampicillin plus pivmecillinam is more effective than pivampicillin alone in the treatment of recurrent and chronic lung infections with Haemophilus influenzae in patients with chronic obstructive pulmonary disease (COPD) or cystic fibrosis (CF). Fifty-six children and young adults with COPD or CF were randomised to the clinical study. The patients were allocated at random to receive perorally either pivmecillinam, 40 mg/kg/day, combined with pivampicillin, 50 mg/kg/day, or pivampicillin 50 mg/kg/day alone for 14 days. A cross-over pharmacokinetic study using the same drugs was carried out in 10 CF patients to determine the antibiotic concentrations in serum and sputum after a single dose of each drug. The clinical study showed no significant differences in clinical scoring, lung function tests or adverse events after treatment with pivampicillin plus pivmecillinam or pivampicillin alone. Follow-up microbiological evaluation 2 and 6 weeks after the end of treatment showed that the offending pathogen was eradicated in 68% of the patients treated with pivampicillin plus pivmecillinam and in 67% of the patients treated with pivampicillin alone. Reinfection with another biotype was more common in the combination group (50% vs. 21%) than in the pivampicillin group. In the pharmacokinetic study the median peak serum concentration occurred two hours after intake of tablets. The efficacy of double beta lactam treatment in lung infections with H. influenzae appears to be equivalent to that of ampicillin on clinical lung symptoms, lung function tests, adverse effects and bacteriology.

N-acetyl-D-glucosamine medium improves recovery of Haemophilus influenzae from sputa of patients with cystic fibrosis

A modified selective medium supplemented with N-acetyl-D-glucosamine (NAG), hemin, and NAD plus two cefsulodin disks, for primary isolation of nonencapsulated Haemophilus influenzae from sputum of patients with cystic fibrosis, is described. Isolation of H. influenzae from this medium, designated NAG medium, was compared with recovery by standard media and immunochemical detection of H. influenzae with monoclonal antibody 8BD9. The H. influenzae recovery rate increased from 31% with standard media to 42% with NAG medium. H. influenzae was detected by immunoperoxidase staining in 54% of the sputum specimens. The results of this study demonstrate that NAG medium improves H. influenzae recovery, although immunoperoxidase staining is superior for detection of H. influenzae from sputum of cystic fibrosis patients.

Haemophilus influenzae is frequently detected with monoclonal antibody 8BD9 in sputum samples from patients with cystic fibrosis

To determine the frequency of Haemophilus influenzae in sputum from patients with cystic fibrosis (CF), 477 sputum samples obtained from 86 CF patients were analyzed by standard culture and by the in situ immunoperoxidase staining technique with monoclonal antibody 8BD9. H. influenzae was isolated from 109 sputum samples (23%) from 45 patients (52%) and detected by immunoperoxidase staining in 175 sputum samples (37%) obtained from 63 patients (73%). The results of this study demonstrate the frequent presence of H. influenzae in sputum samples from CF patients.

Microbiology of airway disease in patients with cystic fibrosis

Individuals with cystic fibrosis have abbreviated life spans primarily due to chronic airway infection. A limited number of types of organisms are responsible for these infections, with Staphylococcus aureus and Pseudomonas aeruginosa being of primary importance. In the pre-antibiotic era, greater than 90% of deaths due to infection were caused by S. aureus and death usually occurred in the first 2 years of life. With the advent of effective antistaphylococcal therapy, life spans increased and P. aeruginosa became the pathogen of primary importance. P. aeruginosa isolates recovered from patients with cystic fibrosis have a unique phenotypic characteristic referred to as "mucoid." The mucoid phenotype is due to the production of a mucoid exopolysaccharide. A mucoid exopolysaccharide is believed to play a central role in the establishment of chronic pseudomonal lung infection in these patients. A third organism, Pseudomonas cepacia, has recently been detected in the airways of older patients with cystic fibrosis and is associated with increased mortality. The virulence of P. cepacia is not understood, but the organism is extremely refractory to antimicrobial therapy. Other bacteria, including Haemophilus influenzae and members of the family Enterobacteriaceae, appear to play a secondary role in airway infection. Aspergillus fumigatus is the most important fungal agent causing allergic bronchopulmonary disease. The role of viruses has only recently been examined. At least in some patients with cystic fibrosis, respiratory syncytial virus may be important in predisposing to subsequent bacterial infections.

Haemophilus infection in cystic fibrosis

Twenty seven patients with cystic fibrosis under the age of 12 years and 27 matched patients with asthma were followed up in a prospective study for one year. The isolation rate of non-capsulated strains of Haemophilus influenzae from cough swabs and sputum specimens taken at routine clinic visits every two months was significantly greater in cystic fibrosis than in asthma. Haemophilus para-influenzae was equally common in both groups. During exacerbations the isolation rate of H influenzae in cystic fibrosis was significantly greater than at other times, whereas in asthma there was no significant difference. The distribution of biotypes of H influenzae and H parainfluenzae was similar in the two groups. In cystic fibrosis, biotype I was associated with exacerbations. Biotype V was more common than in previous studies, but was not associated with exacerbations.

Comparison of amoxycillin/clavulanate with amoxycillin in children and adults with chronic obstructive pulmonary disease and infection with Haemophilus influenzae

71 children and adults (median age 7 years) with chronic obstructive pulmonary disease in which ampicillin-sensitive Haemophilus influenzae were isolated from lower airway secretions were included in a single-blind study comparing amoxycillin/clavulanate and amoxycillin alone. The dosage of amoxycillin was 50 mg/kg/day given together with probenecid and divided in 3 doses. Duration of treatment was 14 days. Clinical and bacteriological examinations were performed at study entry and again immediately after the treatment period. A late bacteriological follow-up 1.5 months after entry was performed. 65 patients were eligible for analysis of clinical outcome, and no difference between the groups was found. Side-effects were mild at a frequency of 3% for either preparation. In terms of eradication of the initially isolated H. influenzae amoxycillin/clavulanate tended to be better than amoxycillin, although the difference was not significant (70% and 57%, respectively). In a subset of 33 patients with polymicrobial flora amoxycillin/clavulanate was significantly more effective than amoxycillin. However, amoxycillin/clavulanate did not significantly reduce the emergency of beta-lactamase producing H. influenzae during treatment, and thus offers no advantage over amoxycillin in patients with amoxycillin-sensitive H. influenzae. The combination should be reserved to patients with either polymicrobial flora or ampicillin-resistant H. influenzae.

Efficacy of oral fluoroquinolones versus conventional intravenous antipseudomonal chemotherapy in treatment of cystic fibrosis

The clinical efficacy of the conventional aminoglycoside plus beta-lactam treatment was compared to that of monotherapy with oral quinolones in 26 adult cystic fibrosis patients in an open prospective clinical trial in which six two-week courses of antipseudomonas treatment were administered with an interval of approximately three months between treatments. In each patient two courses of conventional treatment were followed by two courses of quinolone treatment and then by another two courses of conventional treatment. The observed improvements in pulmonary function were somewhat higher when the patients received conventional treatments, and in the most seriously affected patients conventional treatment was significantly better than quinolone treatment. On the basis of these findings it is suggested that quinolone monotherapy cannot replace conventional antipseudomonal chemotherapy in patients with severe pulmonary involvement.

In situ hybridization for the detection of Haemophilus in sputum of patients with cystic fibrosis

In this study we performed in situ hybridization using biotin-labelled total genomic DNA of Haemophilus influenzae type b as a probe on: (1) smears containing bacteria cultured in vitro: all haemophilus species that can be found in the human respiratory tract appeared to be positive and a large number of other bacterial species appeared to be negative in this in situ hybridization test; (2) sputum smears from 287 patients with bronchitis: the hybridization test was positive on all but 2 of the 44 smears derived from patients whose culture yielded haemophilus and additionally on 12 smears derived from patients, whose culture was negative; and (3) sputum smears from 7 patients suffering from cystic fibrosis (CF): the hybridization test was positive in all these 7 sputum smears, while the culture only yielded haemophilus in 3 cases. The higher sensitivity of the hybridization test compared to culturing could mainly be explained by the failure to detect haemophilus in culture caused by masking due to overgrowth by other bacteria. In conclusion the in situ hybridization test, which can be performed in only 4 h, is a sensitive and specific method for the detection of haemophilus in sputum and is particularly useful in CF patients, where overgrowth by pseudomonas often interferes with diagnosis by culturing.

A comparative study of amoxycillin and pivampicillin in persistent Haemophilus influenzae infection of the lower respiratory tract in children with chronic lung disease

A double-blind cross-over study was undertaken to compare the efficacy of amoxycillin and pivampicillin on Haemophilus influenzae infection of the lower respiratory tract in children. 20 patients with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD) due to other causes were included in the study. All patients had a history of regularly harbouring H. influenzae in sputum and repeated treatment failures with pivampicillin. 18 completed two 14-day courses in random order with equimolar doses of pivampicillin (80 mg/kg/day) and amoxycillin (62 mg/kg/day). Both drugs were well tolerated with no serious side effects, but pivampicillin was associated with more pronounced nausea. In steady state the mean serum concentrations of antibiotics 2 and 4 h after medication were 9.7 and 3.7 micrograms/ml for pivampicillin and 19.1 and 7.9 micrograms/ml for amoxycillin (p less than 0.01). Eradication of H. influenzae and clinical improvement was seen in one-third of the courses with both drugs. Betalactamase producing ampicillin-resistant strains emerged during 58% of the amoxycillin courses, but only in 16% of the pivampicillin courses (p less than 0.001). The high number of treatment failures and the development of resistant strains indicate that betalactamase inhibitors may possibly improve the efficacy of these drugs, especially of amoxycillin, in these patients.