Moraxella Species Research Articles

Treatment outcome of Moraxella keratitis: our experience with 18 cases--a retrospective review.

To analyze the clinical presentation, predisposing risk factors, in vitro antimicrobial susceptibility, and especially the outcome of therapy of Moraxella keratitis. Retrospective review of 18 culture-proven cases of Morarella keratitis. Morarella keratitis was associated with Hansen's disease, uncontrolled diabetes mellitus, herpes zoster ophthalmicus, and chickenpox of the recent past and severe protein energy malnutrition. Other associated ocular conditions included lagophthalmos, blepharitis, steroid therapy, corneal degeneration, and scleritis. In four patients, no systemic or ocular predisposing factors could be identified. Three patients presented with an indolent peripheral, anterior stromal infiltrate while the remaining patients showed a central or paracentral ulceration with or without hypopyon. Moraxella species was the only pathogen isolated in 11 cases, whereas mixed infection was seen in seven cases. All isolates were sensitive to ciprofloxacin. Eight of 18 strains of Moraxella were resistant to cefazolin. All 14 eyes for which the follow-up data were available responded to medical treatment alone. Although considered to be associated with poor outcome, our experience suggests that a favorable outcome can be expected in Moraxella keratitis. Cefazolin resistance (as seen in our series) may pose a problem and, hence, monitoring of antimicrobial susceptibility would be beneficial. In view of cefazolin resistance, ciprofloxacin monotherapy appears to be an effective method in the medical management of these cases.

Bacterial lactoferrin receptors.

Lactoferrin is thought to play a pivotal role in prevention of infection in the host and its ability to sequester iron from potential pathogens has been considered an important component of its antimicrobial function. A number of bacterial species in the Neisseriaceae have developed a mechanism for acquiring iron directly from this host glycoprotein which involves surface receptors capable of specifically binding lactoferrin. Initial attempts at identifying the receptor proteins in Neisseria and Moraxella species using affinity isolation with immobilized lactoferrin under high stringency conditions presumptively identified a single 100 kDa receptor protein, LbpA (formerly Lbp1). Under modified affinity isolation conditions a second 84 kDa lactoferrin binding protein was isolated and had been presumptively identified as LbpB. This protein was not isolated from a CopB-ve isogenic mutant of Moraxella catarrhalis, indicating that it was in fact CopB. However, another lactoferrin binding protein isolated under high stringency conditions, that comigrated with LbpA in most, but not all, M. catarrhalis strains, was identified by convalescent antisera. Its biochemical properties suggested that it indeed was LbpB. The identity of these proteins was confirmed by preparing isogenic mutants with the lbpA and lbpB genes. Growth studies with isogenic mutants deficient in LbpB, LbpA, CopB or FbpA were performed to evaluate their role in iron acquisition from lactoferrin. LbpA and FbpA were essential for this process, supporting prior models of the iron acquisition pathway. LbpB was not essential which is remniscent of studies with the bacterial transferrin receptors. The isogenic CopB-ve isogenic mutants were deficient in iron acquisition from both transferrin and lactoferrin, suggesting that it is a key component in both pathways. A model providing an alternate explanation of the data is presented. The role and surface accessibility of the lactoferrin receptor proteins suggests that they might be useful vaccine antigens and the preferentially reactivity of convalescent antisera with LbpB suggests that it may be the prime candidate.

Phylogeny of the family Moraxellaceae by 16S rDNA sequence analysis, with special emphasis on differentiation of Moraxella species.

Thirty-three strains previously classified into 11 species in the bacterial family Moraxellaceae were subjected to phylogenetic analysis based on 16S rRNA sequences. The family Moraxellaceae formed a distinct clade consisting of four phylogenetic groups as judged from branch lengths, bootstrap values and signature nucleotides. Group I contained the classical moraxellae and strains of the coccal moraxellae, previously known as Branhamella, with 16S rRNA similarity of > or = 95%. A further division of group I into five tentative clusters is discussed. Group II consisted of two strains representing Moraxella atlantae and Moraxella osloensis. These strains were only distantly related to each other (93.4%) and also to the other members of the Moraxellaceae (< or = 93%). Therefore, reasons for reclassification of these species into separate and new genera are discussed. Group III harboured strains of the genus Psychrobacter and strain 752/52 of [Moraxella] phenylpyruvica. This strain of [M.] phenylpyruvica formed an early branch from the group III line of descent. Interestingly, a distant relationship was found between Psychrobacter phenylpyruvicus strain ATCC 23333T (formerly classified as [M.] phenylpyruvica) and [M.] phenylpyruvica strain 752/52, exhibiting less than 96% nucleotide similarity between their 16S rRNA sequences. The establishment of a new genus for [M.] phenylpyruvica strain 752/52 is therefore suggested. Group IV contained only two strains of the genus Acinetobacter. Strategies for the development of diagnostic probes and distinctive sequences for 16S rRNA-based species-specific assays within group I are suggested. Although these findings add to the classificatory placements within the Moraxellaceae, analysis of a more comprehensive selection of strains is still needed to obtain a complete classification system within this family.

Experience with a broth culture technique for diagnosis of bacterial keratitis.

To determine if a broth culture technique is a practical means for bacteriological investigation of keratitis. Twenty-seven eyes of 27 patients with a clinical diagnosis of bacterial keratitis were included in a prospective and non-comparative study at a Danish referral hospital. A corneal scrape was inoculated directly into broth medium which was transferred to the diagnostic laboratory for incubation and subculture. Culture was negative in 4 patients, and 19 of the remaining 23 patients had a pure growth of either Pseudomonas aeruginosa (n = 8), Staphylococcus aureus (n = 2), Streptococcus pneumoniae (n = 2), Haemophilus influenzae biotype III (n = 1), Moraxella species (n = 1), Corynebacterium species (n = 1), or coagulase-negative staphylococci (n = 4). In 4 patients there was a mixed gram-positive growth. There was no association between microbiological findings and previous topical antibiotic therapy. Contamination and lack of quantitative assessment of growth proved not to be a problem. By broth culture technique we identified a definite pathogen (P. aeruginosa, S. aureus or S. pneumoniae) in 44% of patients (95% binomial confidence limits: 25-65%). The technique may replace the standard technique of direct plate culture under circumstances where it is difficult to keep a supply of fresh media or transport inoculated plates.

Moraxella boevrei sp. nov., a new Moraxella species found in goats.

Six Moraxella-like strains that formed a phenotypically homogeneous group were isolated from the nasal flora of healthy goats. Total genomic DNA-DNA hybridization, rRNA gene restriction pattern, DNA base composition, and genetic transformation studies were performed to determine the relationships of these bacteria to species belonging to the genus Moraxella and other fastidious gram-negative species. The new group of isolates was very homogeneous, as shown by rRNA gene restriction fragment length patterns (ribotyping), and these organisms displayed high relative binding ratios (RBRs) to each other in DNA-DNA hybridization experiments (RBRs, > or = 58%) but distinctly lower levels of DNA homology with all other species investigated. However, the RBRs obtained with species of the genus Moraxella were higher than the RBRs obtained with all other gram-negative strains examined. Although the new strains had most of the Moraxella bovis phenotypic characteristics except nitrate reduction, quantitative and qualitative genetic transformation data led to the conclusion that they belong to a distinct new cluster in the genus Moraxella. The results of this study, combined with the general morphological and phenotypic profiles of the new strains, are consistent with the creation of a new Moraxella species, for which the name Moraxella boevrei is proposed. Strain 88365 (= ATCG 700022 = CCUG 35435 = NCTC 12925 = CIP 104716) is the type strain of M. boevrei.

Sparfloxacin worldwide in vitro literature: Isolate data available through 1994

Sparfloxacin is a piperazinyl, cyclopropyl-fluoroquinolone with broad-spectrum antibacterial activity. Compared to other quinolones, sparfloxacin displays improved activity against a variety of pathogens including Staphylococcus, Streptococcus, Enterococcus, Chlamydia, Mycoplasma, Ureaplasma, and Mycobacteria species. Other susceptible organism groups include Haemophilus, Legionella, Moraxella, Neisseria, Aeromonas, Acinetobacter, Bordetella, Brucella, Campylobacter, Gardnerella, and Helicobacter species. Most Enterobacteriaceae are also susceptible, whereas most isolates of Pseudomonas aeruginosa are not. Sparfloxacin is bactericidal. Activity is generally stable to variations of inoculum, pH, and cation concentration, and it is unchanged in the presence of 5% sodium cholate or 70% human serum. Susceptibility to the drug is diminished in urine. Cross-resistance, although incomplete, has been documented with other quinolones, but not with other antimicrobic classes.

Isolation and characterization of a new biovar of Moraxella bovis from healthy caprine nasal swabs

Twenty-four strains of presumptive Moraxella and Branhamella spp. isolated from healthy small ruminant nasal swabs and nine collection strains of the two above genera were compared by means of physiological, enzyme hydrolysing procedures and experimental infectivity tests. Four physiological groups were established. One new biovar of Moraxella, intermediate between Moraxella bovis and Moraxella lacunata was identified from goat nasal isolates. Corneal swabbing and instillation in mice of such Moraxella strain gave a mild transitory photophobia as did the collection strain CIP 7039 Moraxella bovis used in this study. Taxonomic studies are warranted to determine whether it is a new Moraxella species or a Moraxella bovis subspecies.

Detoxification of the Plant Toxin Fluoroacetate by a Genetically Modified Rumen Bacterium

We isolated the fluoroacetate dehalogenase gene (H1), from Moraxella species strain B, and placed it under the transcriptional control of a 154 bp fragment of the erm gene promoter. The promoter/gene construct was attached to the Butyrivibrio fibrisolvens shuttle vector pBHerm, and the resulting dehalogenase expression plasmid (pBHf) was transferred to B. fibrisolvens OB156 by electroporation. The erm gene promoter directed expression of dehalogenase activity in both E. coli and B. fibrisolvens OB156. Cell-free lysates of the genetically modified OB156 defluorinated 10.6 nmol fluoroacetate/min/mg protein. Growing cultures of OB156 were able to detoxify fluoroacetate in the culture medium, at the rate of 9.9 nmol/min/mg. Plasmid pBHf was retained by 100% of OB156 cells after 500 generations of non-selective culture. The restriction pattern of pBHf remained unchanged after extensive non-selective growth and host bacteria continued to produce active dehalogenase. The construction of rumen bacteria that are able to detoxify an important natural poison supports the feasibility of using genetically modified rumen bacteria to aid animal production.

PINK SALMON (ONCORHYNCHUS GORBUSCHA) QUALITY DURING ICE AND CHILLED SEAWATER STORAGE

ABSTRACTPink salmon were stored up to ten days in ice, chilled seawater (CSW), transferred from ice to CSW and from CSW to ice, and evaluated by chemical, physical, microbiological, and sensory methods. The sensory quality of CSW‐held fish declined at a faster rate than for iced fish. CSW‐held fish had higher weight gain, higher salt and hypoxanthine levels and had softer texture than iced fish. Microbial counts were highest for iced fish and a two‐log increase occurred during storage. Moraxella species were predominant in the microbial flora of iced fish whereas Pseudomonas species were predominant in the microbial flora of CSW‐held fish. Ice was superior to CSW for maintaining salmon quality.

Complement deficiency predisposes for meningitis due to nongroupable meningococci and Neisseria-related bacteria.

Nongroupable meningococci or bacteria related to the genus Neisseria rarely cause meningitis. Complement deficiency has been identified as a major predisposing factor for meningococcal disease. To assess whether patients with meningitis due to such strains have a complement deficiency, we studied 12 persons. Six patients had meningitis due to nongroupable strains of meningococci, and six patients had meningitis due to Moraxella species or Acinetobacter species. Inherited complement component C7 or C8 deficiency was found in two persons who had had meningitis due to nongroupable meningococci, and one C8-deficient person had had meningitis caused by Moraxella osloensis. Hypocomplementemia resulting from CSF drain-associated shunt nephritis was found in one person with meningitis due to Moraxella nonliquefaciens and in one person with meningitis due to Acinetobacter lwoffi. This rather high frequency of inherited or acquired complement deficiencies among patients with meningitis due to nongroupable meningococci, Moraxella species, and Acinetobacter species justifies the recommendation that such patients must be studied for complement deficiency.

Branhamella (Moraxella) catarrhalis Endophthalmitis

Branhamella (Moraxella) catarrhalis is a gram-negative diplococcus that is morphologically indistinguishable from Neisseria . 1 In 1970, M catarrhalis was transferred to a new genus, Branhamella , and separated from other species of Moraxella. Branhamella catarrhalis principally colonizes the upper respiratory tract. It is a common cause of otitis media and sinusitis and has become an increasingly important pathogen for lower respiratory tract infections in patients with chronic obstructive pul monary disease. Approximately 75% of strains of B catarrhalis produce β-lactamase and are therefore resistant to penicillin and penicillin derivatives. Branhamella catarrhalis may also exhibit resistance to vancomycin or clindamycin. It remains sensitive to most other oral or intravenous antibiotics. The related Moraxella organisms are principally associated with external eye disease, especially corneal ulcers in debilitated patients. Outbreaks of Moraxella conjunctivitis in children have also been reported. To our knowledge, Moraxella species have been reported as the etiologic agent in three cases

Central venous catheter infection caused by Moraxella osloensis in a patient receiving home parenteral nutrition

We report the first case of a central venous catheter infection caused by Moraxella osloensis, which was successfully treated without catheter removal. The isolation, identification, and pathogenesis of this species are discussed. It is recommended that Moraxella isolates be identified to species in order to determine the relative pathogenic and opportunistic roles of the various Moraxella species. Our case also demonstrates that catheter sepsis caused by some Gram-negative organisms may be amenable to systemic antibiotic therapy without the necessity of catheter removal.

Polyphasic Taxonomy Leading to the Proposal of Moraxella canis sp. nov. for Moraxella catarrhalis-Like Strains

The taxonomic position of a group of 16 Moraxella catarrhalis-like strains, isolated mainly from dogs, was examined by using morphological tests, biochemical tests, serology, ribotyping with oligonucleotide probes, polymerase chain reaction typing of the 16S rRNA gene and the 16S-23S rRNA gene spacer region, polyacrylamide gel electrophoresis of total proteins, fatty acid profiles, moles percent G+C, dot spot and in-solution DNA-DNA hybridizations, and DNA-rRNA hybridizations. It was found that these organisms constitute a distinct cluster within the genus Moraxella. Since they differ genotypically as well as phenotypically from previously described Moraxella species, a new species, Moraxella canis, is proposed to accommodate these isolates. The type strain is LMG 11194 (= N7 = CCUG 8415A).

Moraxella lincolnii sp. nov., Isolated from the Human Respiratory Tract, and Reevaluation of the Taxonomic Position of Moraxella osloensis

A polyphasic taxonomic study was performed to determine the relationships of 10 Moraxella-like strains isolated mainly from the human respiratory tract in Sweden. Two of the strains formed a separate subgroup on the basis of both their protein contents and their fatty acid contents. However, the overall protein and fatty acid profiles revealed that all 10 strains were highly related. Representative strains of the two subgroups exhibited high DNA binding values (98%) with each other and had an identical DNA base ratio (44 mol% G+C). DNA-rRNA hybridizations revealed that this taxon can be included in the genus Moraxella, which is only distantly related to phenotypically similar genera, such as the genera Neisseria and Kingella. The results of an extensive phenotypic analysis indicated that the general biochemical profile of the 10 strains conforms with the description of the genus Moraxella given in Bergey's Manual of Systematic Bacteriology. We therefore consider these organisms members of a new Moraxella species, for which the name Moraxella lincolnii is proposed. Furthermore, we also conclude that Moraxella osloensis belongs, genotypically as well as phenotypically, to the genus Moraxella.

Identification of Moraxella-like bacteria isolated from caprine and ovine nasal flora.

Twenty four Moraxella related bacterias were isolated from healthy caprine and ovine nasal swabs and were investigated by classic biochemical tests and by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins in comparison with 9 reference strains. Proteolytic and haemolytic strains were investigated by electron microscopy. The biochemical results clustered field isolates in four groups corresponding to Branhamella and Moraxella species. Proteolytic, haemolytic and fimbriated field isolates showed the same morphological structure and biochemical features as Moraxella bovis. SDS-PAGE results indicated that DICE coefficient between a field isolate and the corresponding reference strain can be as 62.5%; 41.7% and 36% respectively for the groups 1, 3 and 4. The group 2 showed a similarity percentage over 75% with the reference strain Moraxella nonliquefaciens. This results indicated that a non proteolytic but haemolytic bacteria, closely related to Moraxella nonliquefaciens was commonly isolated from small ruminants nasal flora. These animals can also be hosts of a subspecies of Moraxella bovis.

Moraxella species - a review of ocular isolates recovered from 19 patients

Moraxella spp. (other than M. catarrhalis) are recognised ocular pathogens most commonly causing conjunctivitis or keratitis. Penicillin has traditionally been considered the drug of choice for treatment. We reviewed 19 isolates recovered from eye specimens over an 18-month period. Minimal inhibitory concentrations (MIC's) were performed to nine commonly used antibiotics using the E- test (AB Biodisk Sweden) and isolates tested for beta lactamase using nitrocefin impregnated discs (BBL). Therapy, response to treatment and possible predisposing factors were able to be reviewed in 16 patients and the prevalence of Moraxella spp as a cause of keratitis over this period was assessed. Isolates were found to be sensitive to most antimicrobials with the exception of penicillin and ampicillin. MIC's to penicillin generally fell in the resistant category (MIC 90 = 1) and included isolates that tested beta lactamase negative. All 13 beta lactamase positive isolates were identified as M. nonliquefaciens. Fourteen patients had keratitis ranging from mild to severe and most had predisposing corneal or adnexal pathology. Treatment involved hospital admission and intensive topical antibiotic therapy, response was usually slow. Moraxella spp comprised 9% of keratitis isolates over a 14-month period making it the 4th most common isolate. It is recommended that beta lactamase testing be performed routinely on such isolates. The method may not, however, detect beta lactamases produced by some Moraxella spp. In vitro findings would suggest that penicillin may no longer be the optimal choice for treatment. Moraxella spp. (other than M. catarrhalis) are recognised ocular pathogens most commonly causing conjunctivitis or keratitis. Penicillin has traditionally been considered the drug of choice for treatment. We reviewed 19 isolates recovered from eye specimens over an 18-month period. Minimal inhibitory concentrations (MIC's) were performed to nine commonly used antibiotics using the E- test (AB Biodisk Sweden) and isolates tested for beta lactamase using nitrocefin impregnated discs (BBL). Therapy, response to treatment and possible predisposing factors were able to be reviewed in 16 patients and the prevalence of Moraxella spp as a cause of keratitis over this period was assessed. Isolates were found to be sensitive to most antimicrobials with the exception of penicillin and ampicillin. MIC's to penicillin generally fell in the resistant category (MIC 90 = 1) and included isolates that tested beta lactamase negative. All 13 beta lactamase positive isolates were identified as M. nonliquefaciens. Fourteen patients had keratitis ranging from mild to severe and most had predisposing corneal or adnexal pathology. Treatment involved hospital admission and intensive topical antibiotic therapy, response was usually slow. Moraxella spp comprised 9% of keratitis isolates over a 14-month period making it the 4th most common isolate. It is recommended that beta lactamase testing be performed routinely on such isolates. The method may not, however, detect beta lactamases produced by some Moraxella spp. In vitro findings would suggest that penicillin may no longer be the optimal choice for treatment.

Septicaemia caused by a penicillin-resistantMoraxella-like organism in a neutropenic patient

Invasive infections with Moraxella and related species are unusual. In this report we describe a case of septicaemia in an immunocompromised patient caused by a Moraxella-like organism. The organism was difficult to identify in the laboratory and was also unusual in that it was resistant to penicillin.

Microorganisms on Commercially Processed Alaskan Finfish

ABSTRACTWhole and processed Alaskan fish were examined for aerobic plate counts, total coliforms, and Escherichia coli. Washing whole salmon and halibut reduced skin microbial counts from 103/cm2 to 102/cm2. Whole and dressed fish had coliform counts less than 13/cm2 and E. coli counts less than 0.3/cm2. Alaska pollock and Pacific cod fillets had microbial counts between 103/g and 106/g, coliform counts less than 70/g, and E. coli counts less than 4/g. Whole fish contained microbial flora predominated by Moraxella species whereas dressed fish and fillets had microbial flora consisting of Arthrobacter/Corynebacterium, Flavobacterium, and Pseudomonas species. Microorganisms on conveyor belts and other contact surfaces may have contributed contaminants to fillets.

Moraxella atlantae bacteraemia in a patient with systemic lupus erythematosis

We describe the first reported case of human infection caused by Moraxella atlantae (formerly known as CDC group M-3) and its successful treatment with intravenous cefuroxime. The isolation and identification of this species, as well as the pathogenesis of the infection, are discussed. It is recommended that isolates of Moraxella species be speciated so that the epidemiological characteristics and pathogenesis of the infections caused by the various species may be understood more completely.

Infections Caused by Moraxella, Moraxella urethralis, Moraxella-Like Groups M-5 and M-6, and Kingella kingae in the United States, 1953-1980

From 1953 to 1980 the Centers for Disease Control received 933 isolates of bacteria belonging to species of the genus Moraxella, Moraxella-like Moraxella urethralis, now renamed Oligella urethralis, unnamed groups M-5 and M-6, and Kingella kingae. Ordinarily sterile sites were the source of 233 isolates. Moraxella nonliquefaciens, the most common isolate (356 strains), was recovered from upper respiratory or ocular sites in 208 (58%) of the cases. Moraxella osloensis was next most common (199 strains) but was the most frequent blood isolate (44 cases). K. kingae appeared especially invasive, with 58 of 78 isolates from blood, bone, or joint. Of the K. kingae strains, 75% were recovered from children under 6 years, compared with 23% of the other strains from that age group (P less than .01). Of the 74 isolates of group M-5, 53 were from wounds caused by dog bites; no other organism in this series was recovered from such wounds. Sixteen of the 28 M. urethralis isolates were from urine. Cases occurred as single infections, with no evidence of clusters. Of patients with infection of ordinarily sterile sites, 9.3% died; only bacteremia, meningitis, and empyema caused fatalities. Most referring laboratories (98%) had not identified the organisms to species, and only 30% had identified them to correct genus. Susceptibility testing by broth dilution revealed low MICs of penicillin (mean, 0.3; 64% less than 1 micrograms/mL). Moraxella, M. urethralis, M-5, M-6, and Kingella are important but frequently misidentified pathogens for humans; penicillin appears to be the treatment of choice.