A comparison of serum bactericidal activity and phenotypic characteristics of bacteremic, pneumonia-causing strains, and colonizing strains of Branhamella catarrhalis

Article Abstract:

The bacterial organism Branhamella catarrhalis has been isolated in healthy individuals, but it is also considered a pathogen, resulting in lower respiratory tract infections in adults. The mechanism of immunological defense against B. catarrhalis is not well understood. Various responses have been implicated in association with different types of B. catarrhalis infections. The study of characteristics of the site on this organism that is subject to action by immunological factors in the blood serum may provide insight into these mechanisms. Seven colonizing strains of B. catarrhalis were compared with four blood isolates and 12 pneumonia isolates from patients with B. catarrhalis infection. The ability of these isolates to grow in serum taken from a patient with B. catarrhalis bacteremia (bacteria in the blood) and in normal human serum was evaluated. Also, phenotypic (physical) characteristics of the bacteria were observed, such as production of susceptibility to colistin (a substance lethal to bacteria) and sensitivity to trypsin (an enzyme that attacks protein). In the strains that were isolated that caused disease, 7 out of 16 were resistant to serum (43 percent), compared with only one out of seven colonizing strains serum resistant (13 percent). No differences in serum resistance were found between bacteremic strains and strains that caused pneumonia. In the B. catarrhalis strains that caused disease, trypsin zones of inhibition were higher, but no differences in colistin sensitivity or ability to hemagglutinate red blood cells were found that were associated with source of isolation. (Consumer Summary produced by Reliance Medical Information, Inc.)

Physiological aspects, Serum, Blood serum

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A descriptive study of 42 cases of Branhamella catarrhalis pneumonia

Article Abstract:

Branhamella catarrhalis is a bacterial pathogen that can cause sinus and middle ear infections in children, and is also involved in chronic lower respiratory tract infections in adults. However, the role of B. catarrhalis in adult pneumonia has not been clearly defined. To establish a more complete profile of the manifestations of this pathogen in pneumonia, 42 cases of B. catarrhalis pneumonia in adults were examined. The bacteria were isolated from sputum samples of the subjects and pneumonia was confirmed by X-rays. Fifty-five percent of the subjects were over 65 years old and most (69 percent) were malnourished. Almost all of the subjects (98 percent) had underlying respiratory disease. In general, the pneumonia symptoms in these patients were not severe and included chills, malaise, chest pain, and fever. Fever was noted in only 57 percent of the subjects. Although symptoms were not severe, the prognosis was not good. Nine patients died during hospitalization and B. catarrhalis infection was considered to be the major factor in the death of three patients. Three months after discharge, 10 more subjects died of an underlying disease. It is suggested that B. catarrhalis pneumonia has been underreported because the bacteria have been difficult to isolate. B. catarrhalis infection is probably more common than previously thought and the number of cases is increasing. Significant findings included a high mortality and rate of malnutrition associated with this infection, and elderly patients are especially vulnerable. (Consumer Summary produced by Reliance Medical Information, Inc.)

Case studies, Infection, Pneumonia, Bacterial pneumonia

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Antibiotic susceptibilities and drug resistance in Moraxella (Branhamella) catarrhalis

Article Abstract:

The emergence of bacteria resistant to penicillin or ampicillin has made treatment of bacterial infections of the respiratory tract more difficult. This is true of the pathogen Moraxella (Branhamella) catarrhalis, a bacterial organism responsible for lower respiratory tract infections among adults. This resistance is associated with the production of BRO beta-lactamase by certain isolates of B. catarrhalis. Beta-lactamase is an enzyme that is produced by some pathogens and is associated with antibiotic resistance. The designation BRO refers to two closely related enzymes found in the subgenus Branhamella and Moraxella that are associated with beta-lactamase production. These BRO enzymes are relatively weak, but can inactivate penicillin, ampicillin, methicillin, and cefaclor, drugs used to fight infection. B. catarrhalis strains have also been isolated that are resistant to other therapeutic drugs, including vancomycin, trimethoprim, and clindamycin. Reports from Sweden have also isolated B. catarrhalis strains that are resistant to tetracycline, but this has not been substantiated by research in the United States. Resistance to erythromycin has also been reported, but data are still inconclusive. The BRO beta-lactamase produced by B. catarrhalis is phenotypically different from beta-lactamases produced by other pathogens. It is believed that the mechanism of this enzyme also differs from other beta-lactamases, but the mechanism of gene transfer is similar. (Consumer Summary produced by Reliance Medical Information, Inc.)

Analysis, Evaluation, Antibiotics, Drug resistance in microorganisms, Microbial drug resistance, Beta lactamases

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