Respiratory tract carrier rates of Moraxella (Branhamella) catarrhalis in adults and children and interpretation of the isolation of M. catarrhalis from sputum

Synthesis and characterization of lipooligosaccharide-based conjugates as vaccine candidates for Moraxella (Branhamella) catarrhalis

Moraxella (Branhamella) catarrhalis is an important cause of otitis media and sinusitis in children and of lower respiratory tract infections in adults. Lipooligosaccharide (LOS) is a major surface antigen of the bacterium and elicits bactericidal antibodies. Treatment of the LOS from strain ATCC 25238 with anhydrous hydrazine reduced its toxicity 20,000-fold, as assayed in the Limulus amebocyte lysate (LAL) test. The detoxified LOS (dLOS) was coupled to tetanus toxoid (TT) or high-molecular-weight proteins (HMP) from nontypeable Haemophilus influenzae through a linker of adipic acid dihydrazide to form dLOS-TT or dLOS-HMP. The molar ratios of dLOS to TT and HMP conjugates were 19:1 and 31:1, respectively. The antigenicity of the two conjugates was similar to that of the LOS, as determined by double immunodiffusion. Subcutaneous or intramuscular injection of both conjugates elicited a 50- to 100-fold rise in the geometric mean of immunoglobulin G (IgG) to the homologous LOS in mice after three injections and a 350- to 700-fold rise of anti-LOS IgG in rabbits after two injections. The immunogenicity of the conjugate was enhanced by formulation with monophosphoryl lipid A plus trehalose dimycolate. In rabbits, conjugate-induced antisera had complement-mediated bactericidal activity against the homologous strain and heterologous strains of M. catarrhalis. These results indicate that a detoxified LOS-protein conjugate is a candidate for immunization against M. catarrhalis diseases.

Moraxella catarrhalis: clinical significance, antimicrobial susceptibility and BRO beta-lactamases

Moraxella catarrhalis is an important pathogen of humans. It is a common cause of respiratory infections, particularly otitis media in children and lower respiratory tract infections in the elderly. Colonisation of the upper respiratory tract appears to be associated with infection in many cases, although this association is not well understood. Nosocomial transmission is being increasingly documented and the emergence of this organism as a cause of bacteremia is of concern. The widespread production of a beta-lactamase enzyme renders Moraxella catarrhalis resistant to the penicillins. Cephalosporins and beta-lactamase inhibitor combinations are effective for treatment of beta-lactamase producers, and the organism remains nearly universally susceptible to the macrolides, fluoroquinolones, tetracyclines and the combination of trimethoprim and sulfamethoxazole. Two major beta-lactamase forms, BRO-1 and BRO-2, have been described on the basis of their isoelectric focusing patterns. The BRO-1 enzyme is found in the majority of beta-lactamase-producing isolates and confers a higher level of resistance to strains than BRO-2. The BRO enzymes are membrane associated and their production appears to be mediated by chromosomal determinants which are transmissible by an unknown mechanism. The origin of these novel proteins is unknown.

Mapping of a protective epitope of the CopB outer membrane protein of Moraxella catarrhalis

A monoclonal antibody (MAb) (MAb 10F3) directed against the CopB outer membrane protein of Moraxella catarrhalis previously was found to enhance pulmonary clearance of M. catarrhalis in an animal model (M. Helminen, I. Maciver, J. L. Latimer, L. D. Cope, G. H. McCracken, Jr., and E. J. Hansen, Infect. Immun. 61:2003-2010, 1993). In the present study, this same MAb was shown to exert complement-dependent bactericidal activity against this pathogen in vitro. Nucleotide sequence analysis of the copB gene from two MAb 10F3-reactive and two MAb 10F3-unreactive strains of M. catarrhalis revealed that the deduced amino acid sequences of these four CopB proteins were at least 90% identical. Comparison of the amino acid sequences of these proteins allowed localization of possible MAb 10F3 binding sites to five relatively small regions of the CopB protein from M. catarrhalis O35E. When five synthetic peptides representing these regions were tested for their ability to bind MAb 10F3 in a direct enzyme-linked immunosorbent assay system, an oligopeptide containing 26 amino acids was shown to bind this MAb. The actual binding region for MAb 10F3 was localized further through the use of overlapping decapeptides that spanned this 26-mer. A fusion protein containing the same 26-mer readily bound MAb 10F3 and was used to immunize mice. The resultant antiserum contained antibodies that reacted with the CopB protein of the homologous M. catarrhalis strain in Western blot analysis and bound to the surface of both homologous and heterologous strains of M. catarrhalis.

Human immunoglobulin isotype and IgG subclass response to different antigens of Moraxella catarrhalis

Enzyme immunoassays were tested for the determination of antibodies of different isotypes and IgG subclasses to Moraxella catarrhalis in human sera. An assay based on an outer membrane protein preparation (OMP) as antigen was compared to assays using whole bacterial cells and a purified lipopolysaccharide preparation. There was a good correlation between the results obtained with the OMP preparation and the whole-cell antigen. In paired sera, optimal sensitivity was obtained by using the OMP preparation as coating antigen and testing for a rise in IgG3 antibodies. However, patients with high levels of antibodies in acute serum had no or only an insignificant antibody response during infection.

Serum antibody response to outer membrane proteins of Moraxella (Branhamella) catarrhalis in patients with bronchopulmonary infection

A Western blot (immunoblot) method for detecting antibodies against outer membrane protein (OMP) epitopes of Moraxella (Branhamella) catarrhalis was evaluated. Paired serum samples from patients suspected of M. catarrhalis (n = 38) and non-M. catarrhalis (n = 25) bronchopulmonary infection were examined for the presence of antibodies of the immunoglobulin M (IgM), IgG, and IgA classes to OMPs from M. catarrhalis by a gel electrophoresis-immunoperoxidase technique (Western blotting); sera from 40 healthy adult blood donors were also included. A significantly (P = 0.004) more frequent occurrence of IgM-class antibodies and/or an increase in the number of IgG-class antibodies against different M. catarrhalis OMPs from acute- to convalescent-phase serum samples was found for patients with M. catarrhalis (79%) than for patients without M. catarrhalis (40%). IgM-class antibodies against OMPs of M. catarrhalis were found in acute- and/or convalescent-phase serum samples form 58% of patients with M. catarrhalis and 32% of patients without M. catarrhalis. Fifty percent of patients with M. catarrhalis and 16% of patients without M. catarrhalis had, from acute- to convalescent-phase serum samples, an increased number of IgG-class antibodies directed against different OMPs. A total of 34% of patients with M. catarrhalis and 4% of patients without M. catarrhalis had, from acute- to convalescent-phase serum samples, an increased number of IgA-class antibodies directed against different OMPs. The present study indicates that M. catarrhalis is one of the bacteria involved in acute exacerbations of chronic bronchitis.

Branhamella catarrhalis: epidemiology, surface antigenic structure, and immune response

Over the past decade, Branhamella catarrhalis has emerged as an important human pathogen. The bacterium is a common cause of otitis media in children and of lower respiratory tract infections in adults with chronic obstructive pulmonary disease. B. catarrhalis is exclusively a human pathogen. It colonizes the respiratory tract of a small proportion of adults and a larger proportion of children. Studies involving restriction enzyme analysis of genomic DNA show that colonization is a dynamic process, with the human host eliminating and acquiring new strains frequently. The surface of B. catarrhalis contains outer membrane proteins, lipooligosaccharide, and pili. The genes which encode several outer membrane proteins have been cloned, and some of these proteins are being studied as potential vaccine antigens. Analysis of the immune response has been limited by the lack of an adequate animal model of B. catarrhalis infection. New information regarding outer membrane structure should guide studies of the human immune response to B. catarrhalis. Immunoassays which specifically detect antibodies to determinants exposed on the bacterial surface will elucidate the most relevant immune response. The recognition of B. catarrhalis as an important human pathogen has stimulated research on the epidemiology and surface structures of the bacterium. Future studies to understand the mechanisms of infection and to elucidate the human immune response to infection hold promise of developing new methods to treat and prevent infections caused by B. catarrhalis.

Evaluation of purified UspA from Moraxella catarrhalis as a vaccine in a murine model after active immunization

Moraxella catarrhalis causes otitis media, laryngitis, and respiratory infections in humans. A high-molecular-weight outer membrane protein from this bacterium named ubiquitous surface protein A (UspA) is present on all isolates. A monoclonal antibody (MAb) to UspA that recognizes a conserved epitope of this protein has been shown to promote pulmonary clearance of bacteria in passively immunized mice. In the present study, M. catarrhalis heterologous isolates were screened by dot blot with a panel of four additional MAbs specific for surface-exposed epitopes of UspA from M. catarrhalis isolate 035E. Three of the MAbs were specific for 035E, and the fourth reacted with 17 (74%) of the 23 isolates tested. Thus, UspA contains highly conserved, semiconserved, and variable surface-exposed epitopes. The UspA was purified from the 035E isolate by ion-exchange and size-exclusion chromatography, formulated with the adjuvant QS-21, and used to immunize BALB/c mice. Upon pulmonary challenge with either 035E or the heterologous isolate TTA24, significantly fewer bacteria were recovered from the lungs of immunized mice 6 h postchallenge than from control mice. The immune sera from mice or guinea pigs contained high titers of antibodies to the homologous isolate and heterologous isolates in a whole-bacterial-cell enzyme-linked immunosorbent assay. Sera against UspA, whether prepared in mice or guinea pigs, had complement-dependent bactericidal activity toward homologous and 11 heterologous M. catarrhalis isolates. These results indicate that the conserved epitopes of the UspA are highly immunogenic and elicit broadly reactive and biologically functional antibodies. UspA may offer protection against M. catarrhalis infections and is being further evaluated as a vaccine candidate.

A monoclonal antibody reactive with a common epitope of Moraxella (Branhamella) catarrhalis lipopolysaccharides

A hybrid cell line producing a monoclonal antibody (MAb) against Moraxella (Branhamella) catarrhalis lipopolysaccharide (LPS) was established. The specificity of the MAb 1B12 to purified rough LPSs from six strains of M. catarrhalis was ascertained by enzyme-linked immunosorbent assay (ELISA), competitive-inhibition ELISA, and immunoblotting. MAb 1B12 bound to live bacterial cells and culture supernatants from a total of 34 strains of M. catarrhalis, including 12 strains with different LPS serotypes. No cross-reactions with smooth and rough LPSs from selected enterobacterial and nonenterobacterial strains, with other respiratory pathogens, or with Neisseria species were observed. These data suggest that MAb 1B12 recognizes a common epitope of M. catarrhalis LPS which differs from serotype determinants.

Complement resistance is a virulence factor of Branhamella (Moraxella) catarrhalis

The purpose of this study was to investigate complement resistance in Branhamella (Moraxella) catarrhalis isolated from healthy schoolchildren or sputum-producing adult patients. Two techniques were used: a serum bactericidal assay as the gold standard and an easier 'culture and spot' test. Children (age 4-13; n = 303) and patients (n = 1047) showed high colonization/infection rates with B. catarrhalis (31% and 19%, respectively). Complement resistance or intermediate sensitivity occurred frequently in patient isolates (62% and 27%, respectively) and less often in children (33% and 8.5%, respectively; P << 0.0001). In young children (age 4-5 years), the proportion of complement-resistant strains was around 50%. Complement resistance in B. catarrhalis is associated with illness and may hence be considered a virulence factor.

Assessment of complement-mediated killing of Moraxella (Branhamella) catarrhalis isolates by a simple method

Recently, we showed that complement resistance is an important virulence factor of Moraxella (Branhamella) catarrhalis. Our study used a serum bactericidal assay to determine complement resistance in M. catarrhalis. Although the serum bactericidal assay is considered the "gold standard" for determining complement resistance, it is laborious and time-consuming and therefore not well suited for large-scale studies. Using a large number (n = 324) of M. catarrhalis isolates obtained from the sputa of patients with lower respiratory tract infections (n = 200) and young carriers (n = 124), we assessed the value of a simple "culture-and-spot" test as an alternative to the serum bactericidal assay. For both groups of isolates, the degree of concordance between the two tests used was very significant (P < 0.0001). The agreement between the two assays was estimated to be "excellent beyond chance" (as determined by Cohen's kappa test). The culture-and-spot assay is a valuable alternative to the serum bactericidal assay, not only for screening purposes as shown here but also for studying the mechanism of complement resistance in M. catarrhalis at the molecular level.

Evidence of lectin-mediated adherence of Moraxella catarrhalis

Clinical isolates of Moraxella catarrhalis (n = 86) were evaluated for their haemagglutinating activity with different types of erythrocytes. Of all the isolates tested, 12 did not agglutinate with any of the erythrocytes, whereas 65 reacted with human erythrocytes of type A, B, and 0, and 26 with erythrocytes from rabbit, guinea pig, dog, or rat. None of the isolates agglutinated with sheep and goat erythrocytes. The agglutination titres ranged from 0 to 64. Among these isolates, 13 different agglutination patterns could be distinguished. The agglutinating activity was Ca(2+)-dependent and was inhibited by proteases, by temperatures exceeding 50 degrees C and by the addition of D-glucosamine or D-galactosamine. The adherence capacity of the M. catarrhalis isolates to tracheal epithelium correlated with their agglutination titre and could be inhibited by the same treatments. These data provide strong evidence that adherence of M. catarrhalis is mediated by lectins located on the bacterial surface.

Serum antibody response to proteins of Moraxella (Branhamella) catarrhalis in patients with lower respiratory tract infection

We searched for antibodies against Moraxella (Branhamella) catarrhalis proteins in the sera of patients with lower respiratory tract infection. Sera from 48 patients with M. catarrhalis and 39 patients without M. catarrhalis in their lower respiratory tract specimens were studied by a gel electrophoresis-immunoperoxidase technique; sera from 23 healthy adult blood donors were also included. Immunoglobulin G (IgG) antibodies against a 28-kDa protein were found significantly more frequently in patients with M. catarrhalis in lower respiratory tract specimens (71%) than in patients without M. catarrhalis in lower respiratory tract specimens (28%) or healthy adult blood donors (22%). Seroconversion, from the acute to the convalescent stages, occurred in at least eight patients with M. catarrhalis and in one patient without detectable M. catarrhalis. IgG antibodies against other M. catarrhalis proteins were found in most sera, including those obtained from blood donors. By adsorption experiments the 28-kDa protein was demonstrated to be surface exposed. IgM antibodies against an 85-kDa protein were found in serum from one patient from whom M. catarrhalis and Streptococcus pneumoniae were isolated from the lower respiratory tract, while IgA antibodies against M. catarrhalis proteins could not be detected in any serum specimen.

Branhamella catarrhalis in children and adults. A study of prevalence, time of colonisation, and association with upper and lower respiratory tract infections

The colonisation rate of Branhamella catarrhalis in patients from 0 to 45 years of age was examined. Of 561 women admitted to hospital in labour, 6 (1%) carried B. catarrhalis in their throats but none carried the organism in their vaginas. None of 534 newborn babies became colonised at birth or during their 5 days' stay in hospital. Neither were 102 neonates < 1 month of age in hospital colonised. The maximum colonisation rate during childhood was observed in children 1-48 months of age with 143 of 266 (54%) children colonised. Among children 4-15 years of age, four of 57 (7%) children with healthy respiratory tracts were colonised. Significantly more children with upper or lower respiratory tract infections (RTI) were colonised (68%) than were children without such infections (36%), (P < 0.001). After recovery from RTI, the isolation rate in the RTI group fell to that of the non-RTI group. A seasonal variation in prevalence was not observed. Of all the strains of B. catarrhalis isolated, 84% produced beta-lactamase.

Maternal antibodies and acquired serological response to Moraxella catarrhalis in children determined by an enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay (ELISA) for determination of serum immunoglobulin G (IgG) antibodies to Moraxella catarrhalis was developed, with an ultrasonic extract of M. catarrhalis immobilized on polystyrene microtiter plates serving as the antigen. The specificity was determined by adsorption tests. All of the 541 women tested showed a high level of maternal IgG antibodies to M. catarrhalis in umbilical cord blood specimens. One hundred eighty-nine children aged 0 to 15 years were examined. A low level of IgG antibodies to M. catarrhalis in serum was found in children aged up to 1 year; in older children, the levels increased with age. Levels in the same range as maternal IgG antibody levels were reached at the age of 10 years. The level of antibodies in children did not correlate with the state of colonization with M. catarrhalis or with the state of acute lower respiratory tract infection. Pairs of acute-phase and convalescent-phase serum samples did not discriminate between the children with M. catarrhalis in pure culture and those with mixed cultures of M. catarrhalis, Haemophilus influenzae, and Streptococcus pneumoniae. In adult women, high IgG antibody levels and low colonization rates with M. catarrhalis were found, whereas in small children, low IgG antibody levels and high colonization rates were found.

Structural studies of the O-polysaccharide from the lipopolysaccharide of Moraxella (Branhamella) catarrhalis serotype A (strain ATCC 25238)

The polysaccharide of the Moraxella (Branhamella) catarrhalis serotype A lipopolysaccharide was prepared by mild acid hydrolysis followed by gel permeation chromatography. The structure was established by methylation analysis, mass spectrometry, and NMR spectroscopy. It is concluded that the O-antigenic polysaccharide has the following structure. [formula see text] Methylation analysis of the intact lipopolysaccharide showed that the lipid A portion consisted of 6-substituted glucosamine residues. Methylation followed by methanolysis showed that two Kdo residues were present, one terminal and one 4,5-substituted residue. A terminal Kdo thus substitutes the branch-point Kdo in the 4-position.

Moraxella catarrhalis in upper respiratory tract of healthy Yemeni children/adults and paediatric patients: detection and significance

A highly variable carriage rate of Moraxella catarrhalis has been reported in the literature. In order to assess the reasons for this variability, detection rates of this organism from various sites of the upper respiratory tract of children and adults were studied. Throat swabs, oral swabs and nasal swabs from 131 children, 96 adults and 64 paediatric patients with upper respiratory tract infections were cultured on a selective medium. Detection rates of 31.4% in children less than three years of age, 38.5% in children between 4 and 12 years, 11.7% in adults and 21.9% in patients were found, respectively. The reasons for high variability in the carriage rates were many including the number and site of specimen collection, media used for isolation and identification criteria. All isolates were sensitive to amoxycillin-clavulanic acid and co-trimoxazole. A significantly higher share of M. catarrhalis isolates from patients were beta-lactamase producers (12/14, 85.7%) as compared to normal healthy subjects (41.9%), suggesting a cautious approach in the use of beta-lactam antibiotic in respiratory tract infections.

Children with persistent cough--outcome with treatment and role of Moraxella catarrhalis?

52 children with severe cough persisting for more than 10 days were randomized to treatment with amoxycillin/clavulanic acid or placebo in a prospective double-blinded study. Clinically suspected cases of pertussis were excluded, yet 12 (23%) of the children had laboratory verified pertussis infection. The nasopharyngeal colonization showed a predominance of Moraxella catarrhalis which was isolated in 37 (71%) children. Streptococcus pneumoniae and Haemophilus influenzae were isolated in 11 (20%) and 16 (30%) children, respectively. The antibiotic-treated group had a significantly better recovery in both the pediatrician's estimation (p = 0.02) and the independent parental judgement (p = 0.002). These findings are consistent with the view that Moraxella catarrhalis could be directly involved in the pathogenesis of persistent cough in children.

Significance of isolation of Moraxella catarrhalis in routine cultures from the respiratory tract in adults: antibody response studied in a whole cell EIA

The significance of the isolation of Moraxella catarrhalis from sputum or nasopharynx was studied in patients treated at an infectious disease clinic. A whole-cell enzyme immunoassay was used to detect a specific antibody response to M. catarrhalis during infection. In all, 27 patients with respiratory tract infections and 4 with other infections were studied. Titre rises were recorded in 11/23 patients with lower respiratory tract infections, whereas patients with common cold or infections elsewhere all had negative serology. In patients with acute bronchitis, 7/10 patients responded with a significant titre rise. Patients with a low titre in their acute serum sample were those who responded with a titre increase during infection. The findings indicate that isolation of M. catarrhalis from sputa and nasopharyngeal samples in adults is of value for the etiological diagnosis of acute bronchitis and other lower respiratory tract infections, and is therefore important for the choice of drug for treatment, as many isolates are resistant to beta-lactam antibiotics.

Erythromycin treatment is beneficial for longstanding Moraxella catarrhalis associated cough in children

The benefits of antibiotic treatment and a nasopharyngeal culture in children with longstanding cough were analysed in a prospective randomized open study. Clinically suspected pertussis was excluded. Of 40 children given erythromycin for 7 days, 35 (88%) recovered in one week, compared with 17/47 (36%) untreated (p < 0.0001). Erythromycin eliminated Moraxella catarrhalis from the nasopharynx in 21/31 children (68%), compared with spontaneous disappearance in 7/35 (20%) untreated controls (p < 0.001). Purulent bronchitis or otitis media occurred in 2 children (5%) in the treatment group and in 21 (45%) in the control group (p < 0.01). To evaluate the clinical role of isolated pathogens, the 47 untreated subjects were studied. Seven of 35 children harbouring M. catarrhalis recovered, compared with 8/12 in whom this bacterium was absent (p < 0.01). No correlation was found between the isolation of Haemophilus influenzae or Streptococcus pneumoniae and the clinical outcome. Children with persistent cough > 10 days may benefit from erythromycin treatment. M. catarrhalis in the nasopharynx indicates prolonged symptoms and increased risk of bacterial complications.

Role of Moraxella (Branhamella) catarrhalis as a respiratory pathogen in children

During a 12-month surveillance period in 1981-1982, Moraxella catarrhalis was detected in cultures from nasopharyngeal aspirates from 76 (17%) of 449 children hospitalized with middle or lower respiratory tract infection. Seroconversion to M. catarrhalis was positive in 4 (5%) of the 76 patients with M. catarrhalis present in nasopharyngeal aspirates and in 4 (1%) of 373 patients with a negative finding. Although children with respiratory tract infections were often colonized by the organism, this was rarely the infective agent of the middle or lower airways. Four of 8 patients with seroconversion to M. catarrhalis exhibited a concomitant RSV infection. The carriage of this species was more closely associated with parainfluenza virus infections. Serological responses to M. catarrhalis were not associated with acute otitis media, and were also rare in children with pneumonia. It is concluded that bronchopulmonary infections caused by M. catarrhalis are rare in children, and that M. catarrhalis aetiology need not be considered in the selection of antibiotics in cases of community-acquired pneumonia or other infections of the middle or lower respiratory tract affecting primarily healthy children.

Use of molecular methods to characterize Moraxella catarrhalis strains in a suspected outbreak of nosocomial infection

Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of whole cell protein, immunoblotting with normal human serum and restriction endonuclease analysis using Taq I enzyme were applied to 38 clinically significant isolates of Moraxella (Branhamella) catarrhalis obtained during a suspected outbreak of nosocomial infection. Each of 18 strains had individual profiles by at least two of the three methods (unique strains). The remaining 20 strains were assigned to five groups (A-E) on the basis of similarity by at least two of the three methods. Isolates within groups A, D and E were homologous by all three methods. Immunoblot groups B and C had two distinct whole cell protein profiles (B1 and B2) but indistinguishable restriction endonuclease profiles (group B/C). This emphasizes the need to use more than one technique in characterizing strains from suspected outbreaks of nosocomial infection. Grouped strains were more likely to originate from the same hospital ward than unique strains and were associated with a significantly longer median time from patient admission to strain isolation (14 versus 3.5 days, p less than 0.005). Furthermore, the beta-lactamase activity was homologous within the groups. The results suggest that nosocomial infection involving several distinct Moraxella catarrhalis strains persisted over a period of months, involving at least 20 patients on three different wards. Such infection is probably common in wards harbouring suitably predisposed patients. The mode of transmission remains to be elucidated, but the above three techniques possess sufficient reproducibility and discriminatory ability to constitute suitable investigative tools.

Current trends in bacterial respiratory pathogens

The relationship of virulence and antimicrobial susceptibility with morbidity due to bacterial respiratory pathogens is complex and evolving. Ultimately, decreasing the incidence of pneumonia due to bacterial pathogens will be dependent on successful preparation and distribution of effective vaccines. Until effective vaccines are widely available, control of a majority of respiratory infections will depend on promotion of rational therapeutic strategies. Though limited to a few specific serotypes and strains, changes in virulence of bacterial respiratory pathogens have been noted. Co-infections due to multiple respiratory pathogens may increase morbidity; however, the epidemiology of co-infections is not clear. Relationships between respiratory viruses and bacteria may exist that increase virulence of both agents, but information regarding these relationships awaits further investigation. Resistance of respiratory pathogens to the more commonly used antimicrobials, such as penicillin, erythromycin, chloramphenicol, and cotrimoxazole, is being documented globally with increasing frequency. The evolution of antimicrobic resistance, especially among strains of Streptococcus pneumoniae, the most common and deadly agent of lower respiratory tract infections, provides impetus to develop and promote effective pneumococcal vaccines and to search for new and effective antimicrobials.

Beta-lactamase production in Branhamella catarrhalis isolated from lower respiratory tract secretions in Danish children: an increasing problem

Findings in specimens from the lower respiratory tract of children were reviewed retrospectively in order to assess the rate of Branhamella catarrhalis and beta-lactamase production. B. catarrhalis was isolated in 139 of 756 samples (18.4%) in 1986 and 211 of 723 samples (29.2%) in 1989. Beta-lactamase production was found in 55.6% of B. catarrhalis strains in 1986 and 80.1% in 1989 (p less than 0.001). Prevalence of beta-lactamase in B. catarrhalis has now reached the same level in Europe as in the USA.