Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MORAXELLA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2006

Visible laser and UV-A radiation impact on a PNP degrading Moraxella strain and its rpoS mutant.

The role of stationary phase sigma factor gene (rpoS) in the stress response of Moraxella strain when exposed to radiation was determined by comparing the stress responses of the wild-type (WT) and its rpoS knockout (KO) mutant. The rpoS was turned on by starving the WT cultures for 24 h in minimal salt medium. Under non-starved condition, both WT and KO planktonic Moraxella cells showed an increase in mortality with the increase in duration of irradiation. In the planktonic non-starved Moraxella, for the power intensity tested, UV radiation caused a substantially higher mortality rate than did by the visible laser light (the mortality rate observed for 15-min laser radiation was 53.4 +/- 10.5 and 48.7 +/- 8.9 for WT and KO, respectively, and 97.6 +/- 0 and 98.5 +/- 0 for 25 s of UV irradiation in WT and KO, respectively). However, the mortality rate decreased significantly in the starved WT when exposed to these two radiations. In comparison, rpoS protected the WT against the visible laser light more effectively than it did for the UV radiation. The WT and KO strains of Moraxella formed distinctly different types of biofilms on stainless steel coupons. The KO strain formed a denser biofilm than did the WT. Visible laser light removed biofilms from the surfaces more effectively than did the UV. This was true when comparing the mortality of bacteria in the biofilms as well. The inability of UV radiation to penetrate biofilms due to greater rates of surface absorption is considered to be the major reason for the weaker removal of biofilms in comparison to that of the visible laser light. This result suggests that high power visible laser light might be an effective tool for the removal of biofilms.

Animals↗
PubMed1986

Incidence of Moraxella conjunctival infection.

Thirty-three cases of Moraxella conjunctival infection, many incorrectly diagnosed as Chlamydia, epidemic keratoconjunctivitis, and herpes simplex infections, were confirmed by bacterial cultures and Giemsa staining during a one-year period. Although Moraxella conjunctivitis is associated with adolescent girls, 13 of our 27 female patients with Moraxella infection (48%) were 20 years or older. Although corneal involvement, preauricular adenopathy, and ocular nodules are not classically associated with Moraxella conjunctivitis, these symptoms were present in 15 cases (45%).

Adolescent↗
PubMed2005

Effect of carbon starvation on p-nitrophenol degradation by a Moraxella strain in buffer and river water.

This study examines the effect of carbon starvation on the ability of a Moraxella sp. strain to degrade p-nitrophenol (PNP). Carbon starvation for 24 h decreased the induction time for p-nitrophenol degradation by the bacterium in a minimal salt medium from 6 to 1 h but it did not completely eliminate the induction time. Moraxella cells with 2-day carbon starvation had an induction time of 3 h and the induction time of the 3-day starved cells was 6 h. A 100% increase in density of the non-starved cells did not affect the induction time for p-nitrophenol degradation by the bacterium, indicating that the initial increase in cell density of the carbon-starved culture did not cause the faster onset of p-nitrophenol degradation. However, the initial uptake of p-nitrophenol of the 1-day carbon-starved Moraxella cells was 3-fold higher than the non-starved cells. A green fluorescent protein gene (gfp)-labelled Moraxella (M6 strain) was constructed to examine the survival of and p-nitrophenol degradation by the bacterium in non-sterile river water samples. Similar p-nitrophenol degradation behaviour was observed in the river water samples inoculated with the M6 cells. The time needed for complete degradation of p-nitrophenol by the non-starved M6 was 19-27 and 33 h in samples spiked with 80, 200 and 360 microM p-nitrophenol, respectively. However, the 1-day carbon-starved inocula required about 16 h to degrade the p-nitrophenol completely regardless of its concentration in the water samples. Survival of the carbon-starved and non-starved M6 was not significantly different from each other in the river water regardless of the p-nitrophenol concentration. In the absence of p-nitrophenol, the inoculum density decreased continuously. At 200 and 360 microM p-nitrophenol, the cell densities of M6 increased in the first two days of incubation and declined steadily afterward.

Buffers↗
PubMed1980

A survey of Moraxella corneal ulcers in a derelict population.

Infection with diplobacilli of the Moraxella group was the most common cause of bacterial corneal ulcer in a population of derelict alcoholics living in the Bowery district in New York City from 1965 through 1968. No distinction could be made between Moraxella subspecies on the basis of severity of ulcer or antibiotic sensitivities. Of 100 Bowery inhabitants examined, 35 harbored Moraxella in their noses. After 1968 and coinciding with an improvement in nutrition and sanitation, but with no apparent change in the incidence of alcoholism in this population, we noted a marked decline in the incidence of corneal ulcers caused by Moraxella species.

Adult↗
PubMed1975

The metabolism of benzoate by Moraxella species through anaerobic nitrate respiration. Evidence for a reductive pathway.

Moraxella sp. isolated from soil grows anaerobically on benzoate by nitrate respiration; nitrate or nitrite are obligatory electron acceptors, being reduced to molecular N2 during the catabolism of the substrate. This bacterium also grows aerobically on benzoate. 2. Aerobically, benzoate is metabolized by ortho cleavage of catechol followed by the beta-oxoadipate pathway. 3. Cells of Moraxella grown anaerobically on benzoate are devoid of ortho and meta cleavage enzymes; cyclohexanecarboxylate and 2-hydroxycyclohexanecarboxylate were detected in the anaerobic culture fluid. 4. [ring-U-14C]Benzoate, incubated anaerobically with cells in nitrate-phosphate buffer, gave rise to labelled 2-hydroxycyclohexanecarboxylate and adipate. When [carboxy-14C]benzoate was used, 2-hydroxycyclohexanecarboxylate was radioactive but the adipate was not labelled. A decarboxylation reaction intervenes at some stage between these two metabolites. 5. The anaerobic metabolism of benzoate by Moraxella sp. through nitrate respiration takes place by the reductive pathway (Dutton & Evans, 1969). Hydrogenation of the aromatic ring probably occurs via cyclohexa-2,5-dienecarboxylate and cyclohex-1-enecarboxylate to give cyclohexanecarboxylate. The biochemistry of this reductive process remains unclear. 6. CoA thiol esterification of cyclohexanecarboxylate followed by beta-oxidation via the unsaturated and hydroxy esters, would afford 2-oxocyclohexanecarboxylate. Subsequent events in the Moraxella culture differ from those occurring with Rhodopseudomonas palustris; decarboxylation precedes hydrolytic cleavage of the alicyclic ring to produce adipate in the former, whereas in the latter the keto ester undergoes direct hydrolytic fission to pimelate.

Anaerobiosis↗
PubMed1999

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

PURPOSE: To analyze the clinical presentation, predisposing risk factors, in vitro antimicrobial susceptibility, and especially the outcome of therapy of Moraxella keratitis. METHODS: Retrospective review of 18 culture-proven cases of Morarella keratitis. RESULTS: 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. CONCLUSIONS: 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.

Adolescent↗
PubMed2003

The Moraxella catarrhalis immunoglobulin D-binding protein MID has conserved sequences and is regulated by a mechanism corresponding to phase variation.

The prevalence of the Moraxella catarrhalis immunoglobulin D (IgD)-binding outer membrane protein MID and its gene was determined in 91 clinical isolates and in 7 culture collection strains. Eighty-four percent of the clinical Moraxella strains expressed MID-dependent IgD binding. The mid gene was detected in all strains as revealed by homology of the signal peptide sequence and a conserved area in the 3' end of the gene. When MID proteins from five different strains were compared, an identity of 65.3 to 85.0% and a similarity of 71.2 to 89.1% were detected. Gene analyses showed several amino acid repeat motifs in the open reading frames, and MID could be called a putative autotransport protein. Interestingly, homopolymeric [polyguanine [poly(G)]] tracts were detected at the 5' ends within the open reading frames. By flow cytometry, using human IgD and fluorescein isothiocyanate-conjugated anti-IgD polyclonal antibodies, most strains showed two peaks: one high- and one low-intensity peak. All isolates expressing high levels of MID had 1, 2, or 3 triplets of G's in their poly(G) tracts, while strains not expressing MID had 4, 7, 8, or 10 G's in their poly(G) tracts or point mutations causing a putative preterminated translation. Northern blot analysis revealed that the mid gene was regulated at the transcriptional level. Experiments with nonclumping variants of M. catarrhalis proved that bacteria lost their MID expression by removing a G in their poly(G) tracts. Moraxella strains isolated from the nasopharynx or from blood and sputum specimens expressed MID at approximately the same frequency. In addition, no variation was observed between strains of different geographical origins (Australia, Europe, Japan, or the United States). MID and the mid gene were found solely in M. catarrhalis, whereas related Neisseria and Moraxella species did not express MID. Taken together, MID appears to be a conserved protein that can be found in essentially all M. catarrhalis strains. Furthermore, MID is governed by poly(G) tracts when bacteria undergo phase variation.

5' Flanking Region↗
PubMed2006

Moraxella keratitis: predisposing factors and clinical review of 95 cases.

AIM: To analyse the clinical presentation, identify predisposing risk factors and evaluate the outcome of treatment of Moraxella keratitis. METHODS: A retrospective analysis was carried out of culture-proved cases of Moraxella keratitis from hospital records during a 10-year period (from December 1995 to November 2005) at the Corneal Unit of the Royal Victorian Eye and Ear Hospital, Melbourne, Australia. RESULTS: 95 episodes of Moraxella keratitis were identified in 92 patients. 3 (3.2%) patients had recurrent keratitis. The mean age of the patients was 70 (range 17-93) years. Multiple predisposing factors were identified in 23 (24%) eyes, including corneal graft (n = 15), previous herpes keratitis (n = 15) and eye lid diseases (n = 15). Adjunctive procedures were carried out in 42 eyes. These included botulinum toxin injection (n = 17), tarsorraphy (n = 12), penetrating keratoplasty (n = 8), enucleation (n = 3), tissue adhesive and bandage contact lens (n = 4), and conjunctival flap (n = 5). Polymicrobial infection was present in 17 eyes. Final visual acuity was counting finger or less in 25 (26%) eyes. CONCLUSIONS: Local ocular predisposing factors play a major role in Moraxella keratitis. This infection has a poor visual outcome attributable to both the nature of the infection and the predisposing factors.

Adolescent↗
PubMed1972

Identification and characterization of Moraxella phenylpyruvica.

Eight strains of Moraxella phenylpyruvica have been isolated from clinical material in the United Kingdom, the first to be reported from this country. They were characterized, together with three strains of M. phenylpyruvica of the National Collection of Type Cultures (NCTC), and compared with NCTC strains of eight other Moraxella species. The strains of M. phenylpyruvica formed a homogeneous group which is readily distinguishable from other Moraxella species. Deamination of phenylalanine is not restricted to M. phenylpyruvica which, however, is urease positive and is stimulated by bile, in contrast to other Moraxella spp.

Adult↗
PubMed2005

The IgD-binding domain of the Moraxella IgD-binding protein MID (MID962-1200) activates human B cells in the presence of T cell cytokines.

Moraxella catarrhalis immunoglobulin D (IgD)-binding protein (MID) is an outer membrane protein with specific affinity for soluble and cell-bound human IgD. Here, we demonstrate that mutated M. catarrhalis strains devoid of MID show a 75% decreased activation of human B cells as compared with wild-type bacteria. In contrast to MID-expressing Moraxella, the MID-deficient Moraxella mutants did not bind to human CD19+ IgD+ B cells. The smallest MID fragment with preserved IgD-binding capacity comprises 238 amino acids (MID(962-1200)). To prove the specificity of MID(962-1200) for IgD, a Chinese hamster ovary (CHO) cell line expressing membrane-anchored human IgD was manufactured. MID(962-1200) bound strongly to the recombinant IgD on CHO cells. Moreover, MID(962-1200) stimulated peripheral blood lymphocyte (PBL) proliferation 5- and 15-fold at 0.1 and 1.0 microg/ml, respectively. This activation could be blocked completely by antibodies directed against the CD40 ligand (CD154). MID(962-1200) also activated purified B cells in the presence of interleukin (IL)-2 or IL-4. An increased IL-6 production was seen after stimulation with MID(962-1200), as revealed by a human cytokine protein array. MID(962-1200) fused to green fluorescent protein (GFP) bound to human B cells and activated PBL to the same degree as MID(962-1200). Taken together, MID is the only IgD-binding protein in Moraxella. Furthermore, the novel T cell-independent antigen MID(962-1200) may, together with MID(962-1200)-GFP, be considered as promising reagents in the study of IgD-dependent B cell activation.

Adhesins, Bacterial↗
PubMed1979

Identification of colonies of Moraxella bovis by plate epi-immunofluorescence.

A modification of the plate epi-immunofluorescence test was found to be a reliable method for the positive identification of colonies of Moraxella bovis when fluorescein isothiocyanate-conjugated globulin prepared against pili from selected strains of M bovis was used. A cross-reaction with other members of the genus Moraxella or other moraxella-like organisms was not observed, except with an equine Moraxella sp, which produced a weak reaction.

Culture Media↗
PubMed1993

Significance, isolation, identification and sensitivity of Branhaemella (moraxella) catarrhalis.

In a study lasting over two years the frequency and sensitivity of moraxella catarrhalis causing respiratory tract infections were studied. Sputum samples from patients with lower respiratory tract infections were screened for moraxella catarrhalis. The organisms isolated identified and their sensitivity determined by simple methods which are practicable. The study shows that 22.4% of the infections were due to moraxella catarrhalis and 98% of the isolates were sensitive to amoxicillin-culvanalic acid (augmentin). The paper signifies the importance of reporting moraxella catarrhalis and its treatment.

Bronchoalveolar Lavage Fluid↗
PubMed1997

Cloning and expression of a gene encoding Moraxella sp. CK-1 autolysin.

A gene of Moraxella sp. CK-1 encoding cell wall lytic activity has been cloned and expressed in E. coli. A genomic library of Moraxella sp. CK-1 was constructed in the multifunctional phagemid vector pT7T3 19u, with partial Sau3A digests of Moraxella sp. CK-1 genomic DNA inserted at the BamHI restriction site. Screening of about 5,000 transformants for cell lysis activity in LB agar plates containing Micrococcus Iuteus cells gave one positive clone harboring the 3.7 kb insert (pMXA282). Restriction mapping and deletion analysis of the recombinant plasmid carrying a 3.7 kb insert suggested that the autolysin gene was located within a 1.1 kb BamHI-PstI fragment. Analysis of extracts of E. coli clone harboring recombinant plasmids on renaturing SDS-polyacrylamide gels containing heat-killed Micrococcus luteus cells showed a clear zone around a polypeptide of about 32 kDa. Lytic activity against Micrococcus luteus cell walls by the cloned autolysin was maximum at pH 9.0. Even in conditions of over pH 10.0, this cloned autolysin showed a vigrous lytic activity. Southern blot analysis suggested the existence of other homologous regions in Moraxella sp. CK-1 genome.

Bacteriolysis↗
PubMed1985

Subspecies differentiation of Moraxella bovis by restriction endonuclease DNA analysis (BRENDA).

A total of 94 strains of Moraxella bovis have been examined by bacterial restriction endonuclease DNA analysis (BRENDA). These strains comprised isolates from the U.S.A., the U.K., in Australia, and from a number of widely separated areas within New Zealand. The strains were classified into a total of 26 different types on the basis of their BRENDA patterns. Fourteen types were present among 34 strains from the U.S.A., eight types from 17 strains in the U.K. three types from five strains in Australia but only one type resulted from all 38 New Zealand strains. Moraxella liquifaciens, M. nonliquifaciens and an atypical Moraxella sp. isolated from cattle eyes in Australia were tested and produced BRENDA patterns clearly different from those of the Moraxella bovis strains. BRENDA, when used with the restriction endonuclease EcoR1, did not provide a means of distinguishing between avirulent, nonhaemolytic M.bovis, and the virulent haemolytic strains.

Journal Article↗
PubMed1996

Colonization and infection with Moraxella catarrhalis in childhood.

In a prospective clinical study, rates of isolation of Moraxella catarrhalis in nasopharyngeal aspirates from 122 children with respiratory tract infection and 72 healthy controls were compared. In the patient group, Moraxella catarrhalis and Streptococcus pneumoniae were the most frequently isolated pathogens (38% and 42%, respectively). Monocultures of each pathogen were equally distributed in patients and controls (41% and 42%), whereas mixed infections were found more frequently in the patient group (42% vs 14%; normal flora, 17% vs 44%). Moraxella catarrhalis appears to be a relevant respiratory pathogen. The isolation of two or more pathogens in nasopharyngeal aspirates seems to be as indicative of relevant infection as is monoculture.

Acute Disease↗
PubMed1992

Moraxella catarrhalis bacteremic pneumonia in adults: two cases and review of the literature.

Moraxella (formerly Branhamella) catarrhalis is a gram-negative coccus now recognized as one of the common pathogens in respiratory infections. Documented cases of bacteremic pneumonia due to this organism, however, have been a rarity. Two cases of Moraxella catarrhalis bacteremic pneumonia in immunosuppressed adult patients are reported. The clinical characteristics of these patients together with those of the seven adult and the six pediatric patients reported to date in the literature, are analyzed. All patients had an underlying condition and most were male. The mean age was 64.9 years. No adult patient had skin lesion, although purpuric rash was frequent in children. The overall morality rate was only 13.3%, in spite of the underlying diseases. In three patients the pneumonia was nosocomial. The seasonal recovery of Moraxella catarrhalis in respiratory infections is significantly increased during the late fall through early spring period. Because most strains are beta-lactamase positive, empiric use of penicillin, ampicillin or amoxicillin for this organism can no longer be recommended.

Adult↗
PubMed2002

Evaluation of the BactiCard Neisseria for identification of pathogenic Neisseria species and Moraxella catarrhalis.

The BactiCard Neisseria (Remel, USA) is a chromogenic enzyme substrate system for identifying Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria lactamica, and Moraxella catarrhalis. The identification system consists of a card with four test circles impregnated with chromogenic substrates for indoxyl butyrate esterase (IB), prolyl aminopeptidase (PRO), gamma-glutamyl aminopeptidase (GLUT), and ss-galactosidase (BGAL). These substrates permit the identification of Moraxella catarrhalis, Neisseria gonorrhoeae, Neisseria meningitidis, and Neisseria lactamica, respectively. After hydration of the circles with buffer, colonies from growth on selective media or a subculture are applied to the four circles. IB and BGAL reactions are read for a blue-green color after 2 and 15 min, respectively. PRO and GLUT reactions are read at 15 min for a red color after addition of a developer reagent. Identifications obtained with the BactiCard Neisseria were compared with those obtained using conventional procedures for 558 isolates in a blinded fashion. The BactiCard Neisseria identified 100% of 254 Neisseria gonorrhoeae, 100% of 125 Neisseria meningitidis, 53 (98.2%) of 54 Neisseria lactamica, and 123 (98.4%) of 125 Moraxella catarrhalis isolates. The BactiCard Neisseria is an accurate and rapid system for identification of these microorganisms in the clinical laboratory.

Bacterial Typing Techniques↗
PubMed2000

Genetic diversity among strains of Moraxella catarrhalis cultured from the nasopharynx of young and healthy Brazilian, Angolan and Dutch children.

The present study describes the carriage patterns and genetic variability of Moraxella catarrhalis strains isolated from children living in different countries. Moraxella catarrhalis is genetically heterogeneous, but little is known about its geographic distribution and phenotypic and genetic diversity in warm-climate countries. A collection of 99 isolates from 30 Brazilian, 19 Angolan and 50 Dutch healthy children, all less than 5 years of age, was investigated for phenotypic and genotypic relatedness. The isolates from the three countries were similar where biochemical reactivity was concerned: 89 strains were beta-lactamase-producing and 87 were complement-resistant as determined by phenotype. There was no geographical difference in the prevalence of beta-lactamase-producing isolates, but the carriage rate of complement-resistant strains was significantly higher in Dutch than in Angolan children (P=0.004). Complement resistance of 66 randomly selected strains was genetically confirmed in a Southern hybridization assay by a novel DNA probe that is specific for complement-resistant strains and that demonstrated a sensitivity of 97% and a specificity of 100%. PCR amplification based on the probe sequence had a sensitivity of 98% and a specificity of 57% when compared to the outcome of a conventional culture spot test. PCR restriction fragment length polymorphism analysis of the MU 46 locus and pulsed-field gel electrophoresis of SpeI DNA macrorestriction fragments revealed genetic heterogeneity of strains from within and between the three countries, and no geographical clustering could be established. In conclusion, similar phenotypic characteristics but genotypic heterogeneity was found among Moraxella catarrhalis strains colonizing children in three different continents.

Angola↗