this is rare), septic arthritis (which is also a rare occurrence),and acute laryngitis in adults and acute otitis media in children. M. catarrhalis is an opportunistic pulmonary invader, and causes harm especially in patients who have compromised immune systems or any underlying chronic disease. Link with bacteremia Moraxella catarrhalis has also been linked with septic arthritis in conjunction with bacteremia. Although cases of bacteremia caused by M. catarrhalis have been reported before, this was the first instance in which bacteremia caused by M. catarrhalis was also associated with septic arthritis. A microbiological evaluation of the patient (a 41-year-old male) revealed that M. catarrhalis was the cause of the disease rather than Neisseria as was previously believed. This was also the second case of M. catarrhalis causing septic arthritis (although in the first case, no mention of bacteremia was made). Along with its relation to septic arthritis, bacteremia is also caused by M. catarrhalis infection, which can range in severity from a slight fever to lethal sepsis and an associated respiratory tract infection is usually also identified. Bacteremia infections caused by M. catarrhalis have a 21% mortality rate among patients. However, this may have been due to a lack of knowledge about the bacterium because of its recent recognition as a pathogen. Infection of high-grade bacteremia was linked with the development of endocarditis. However, the patients without endocarditis has been related to the background of each patient, especially the existence of other illnesses and any possible immune impairments they may have. Also, although bacteremia caused by M. catarrhalis has been infrequently reported, this may be due to a misdiagnosis or oversight because M. catarrhalis was only recently (1990s) identified as an important pathogen. Many chronic diseases in patients with M. catarrhalis bacteremia can be linked to the patients with immune defects or respiratory debility. Likewise, respiratory debility in patients with bacteremic pneumonia caused by M. catarrhalis infection can be linked with increased rates of pharyngeal colonization, enhancement of bacterial adherence to abnormal epithelium, and increased susceptibility of pulmonary parenchyma to infection. Antibiotic resistance Moraxella catarrhalis can be treated with antibiotics, but it is commonly resistant to penicillin, ampicillin, and amoxicillin. Current research priorities involve trying to find a suitable vaccine for this genotypically diverse organism, as well as determining factors involved with virulence, e.g. complement resistance. Lipooligosaccharide is considered one possible virulence factor. Since the recent recognition of M. catarrhalis as