Moraxella nonliquefaciens and M. osloensis Are Important Moraxella Species That Cause Ocular Infections

Abstract

Moraxella is an ocular bacterial pathogen isolated in cases of keratitis, conjunctivitis, and endophthalmitis. Gram-negative brick-shaped diplobacilli from ocular specimens, and slow growth in culture, are early indications of Moraxella ocular infection; however, identifying Moraxella to species can be complex and inconsistent. In this study, bacteria consistent with Moraxella were identified to species using: (1) DNA sequencing coupled with vancomycin susceptibility, (2) MALDI-TOF mass spectrometry, and (3) the Biolog ID system. Study samples consisted of nine ATCC Moraxella controls, 82 isolates from keratitis, 21 isolates from conjunctivitis, and 4 isolates from endophthalmitis. The ATCC controls were correctly identified. For keratitis, 66 (80.5%) were identified as M. nonliquefaciens, 7 (9.0%) as M. lacunata, 5 (6%) as M. osloensis, 2 (2.5%) as Acinetobacter lwoffii, 1 (1.0%) as M. bovis/nonliquefaciens, and 1 (1.0%) as M. osloensis/nonliquefaciens. For conjunctivitis, 9 (43.0%) were identified as M. osloensis, 6 (29.0%) as M. nonliquefaciens, 3 (14.3%) as Roseomonas, 2 (9.5%) as Acinetobacter (parvus, junii), and 1 (4.5%) as M. catarrhalis/nonliquefaciens. From endophthalmitis, 3 of 4 of the isolates were M. nonliquefaciens. Overall, M. nonliquefaciens and M. osloensis were identified in 70% (75 of 107) and 13% (14 of 107) of cases, respectively, totaling 83% (89 of 107). M. nonliquefaciens and M. osloensis are important bacterial pathogens of the eye as determined by DNA sequencing, MALDI-TOF MS, and Biolog. Although Moraxella catarrhalis is a clinical pathogen, other species of Moraxella appear to have a prominent role in eye infections.

Endophytic Bacteria Potentially Promote Plant Growth by Synthesizing Different Metabolites and their Phenotypic/Physiological Profiles in the Biolog GEN III MicroPlateTM Test

“…The tetrazolium dye, reduced to a purple formazan, functions independently of the specific structure of the electron transport chain and is able to detect the ability to metabolize any substrate [11]. The test has been used to identify, among others, bacterial pathogens from clinical samples [11,12] and bacteria from environmental samples [13].…”

Low prevalence of Moraxella catarrhalis in the patients who suffered from conjunctivitis in the southwest of Iran

“…Another point to consider about the bacterium M. catarrhalis is that its prevalence has rarely been evaluated by precise and sensitive molecular methods including PCR, real-time PCR, and loop-mediated isothermal amplification in ocular infections; while most studies of the presence of this bacterium in the respiratory specimens were done with molecular assessment in parallel with the conventional culture method [ 3 , 23 ]. This may indicate that the actual prevalence of this bacterium in ocular infections is lower than the original rate, as the use of molecular methods is much more specific and sensitive than the conventional culture method.…”

“…This may indicate that the actual prevalence of this bacterium in ocular infections is lower than the original rate, as the use of molecular methods is much more specific and sensitive than the conventional culture method. Some previous studies that used conventional culture method, matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), VITEK 2 system, and DNA sequencing have been reported several Moraxella species including M. nonliquefaciens , M. lacunata , M. osloensis , M. atlantae , and M. catarrhalis as a cause of ocular infections [ 3 , 24 , 25 ].…”

“…Moraxella catarrhalis is a Gram-negative, diplococcus bacterium that accounts for many pathologies of humans including otitis media, sinusitis, pneumonia, and conjunctivitis [1][2][3]. The inflammation of the membrane of eyelids is called conjunctivitis [4].…”

“…Conjunctivitis caused by M. catarrhalis is generally non-exudative, persistent, and with no sign of redness [ 9 ]. Currently, medical system laboratories do not have an identical sensitive method for differentiating Moraxella species to genus and species levels in eye infections [ 3 ]. Although the prevalence of Moraxella species in ocular infections has been rarely reported (0.8–19.1%) [ 3 , 10 ], since there was no epidemiological information in this field in the geographical region of southwestern Iran, this study aimed to investigate the phenotypic and molecular presence of M. catarrhalis in conjunctivitis samples collected from patients admitted to one of the main referral ocular infections centers of southwestern Iran.…”