A Western blot (immunoblot) method for detecting antibodies against outer membrane protein (OMP) epitopes of Moraxella ( Branhamella ) catarrhalis was evaluated. Paired serum samples from patients suspected of M. catarrhalis ( n 5 38) and non- M. catarrhalis ( n 5 25) bronchopulmonary infection were examined for the presence of antibodies of the immunoglobulin M (IgM), IgG, and IgA classes to OMPs from M. catarrhalis by a gel electrophoresis-immunoperoxidase technique (Western blotting); sera from 40 healthy adult blood donors were also included. A significantly ( P 5 0.004) more frequent occurrence of IgM-class antibodies and/or an increase in the number of IgG-class antibodies against different M. catarrhalis OMPs from acute- to conva- lescent-phase serum samples was found for patients with M. catarrhalis (79%) than for patients without M. catarrhalis (40%). IgM-class antibodies against OMPs of M. catarrhalis were found in acute- and/or convales- cent-phase serum samples from 58% of patients with M. catarrhalis and 32% of patients without M. catarrhalis . Fifty percent of patients with M. catarrhalis and 16% of patients without M. catarrhalis had, from acute- to convalescent-phase serum samples, an increased number of IgG-class antibodies directed against different OMPs. A total of 34% of patients with M. catarrhalis and 4% of patients without M. catarrhalis had, from acute- to convalescent-phase serum samples, an increased number of IgA-class antibodies directed against different OMPs. The present study indicates that M. catarrhalis is one of the bacteria involved in acute exacerbations of chronic bronchitis.
The role of Moraxella (Branhamella) catarrhalis as a respiratory tract pathogen is increasingly recognized. We looked at the human immune response against individual outer membrane proteins of M. catarrhalis and against the 81-kDa CopB protein, which has previously been shown to be a target for protective antibodies. Paired serum samples from six elderly patients with pneumonia were tested by Western blot (immunoblot) analysis by using outer membrane vesicles of M. catarrhalis 035E as antigen. All of the six convalescent-phase serum samples reacted with a protein which migrated at the position of the CopB protein and with a high-molecular-weight protein of M. catarrhalis; three serum samples also reacted with a 34-kDa outer membrane protein. Paired serum samples from 18 patients, 10 of which had M. catarrhalis infection on the basis of previous serology results, were tested by enzyme immunoassay (EIA) with the CopB protein and whole cells of M. catarrhalis 035E as antigens. Nine patients showed a significant rise in EIA titer between acute- and convalescent-phase sera when whole bacterial cells were used as antigens. Six (67%) patient samples that were positive by the EIA with the whole-cell antigen were also positive by the EIA with the CopB antigen, and six of nine patient samples negative by the EIA with the whole-cell antigen were also negative by the EIA with the CopB antigen. These results suggest that both the CopB and a high-molecular-weight protein are major targets of the immune response against M. catarrhalis, and further studies with greater amounts of patient materials are needed to elucidate the usefulness of CopB as an antigen in etiologic studies.
ABSTRACT Moraxella catarrhalis is a human respiratory pathogen that causes acute otitis media in children and is associated with exacerbations in patients suffering from chronic obstructive pulmonary disease (COPD). The first step in M. catarrhalis colonization is adherence to the mucosa, epithelial cells, and extracellular matrix (ECM). The objective of this study was to eval- uate the role of M. catarrhalis interactions with collagens from various angles. Clinical isolates (n ⴝ 43) were tested for collagen binding, followed by a detailed analysis of protein-protein interactions using recombinantly expressed proteins. M. catarrhalis- dependent interactions with collagen produced by human lung fibroblasts and tracheal tissues were studied by utilizing confocal immunohistochemistry and high-resolution scanning electron microscopy. A mouse smoke-induced chronic obstructive pulmo- nary disease (COPD) model was used to estimate the adherence of M. catarrhalis in vivo. We found that all M. catarrhalis clini- cal isolates tested adhered to fibrillar collagen types I, II, and III and network-forming collagens IV and VI. The trimeric auto- transporter adhesins ubiquitous surface protein A2 (UspA2) and UspA2H were identified as major collagen-binding receptors. M. catarrhalis wild type adhered to human tracheal tissue and collagen-producing lung fibroblasts, whereas UspA2 and UspA2H deletion mutants did not. Moreover, in the COPD mouse model, bacteria devoid of UspA2 and UspA2H had a reduced level of adherence to the respiratory tract compared to the adherence of wild-type bacteria. Our data therefore suggest that the M. ca- tarrhalis UspA2 and UspA2H-dependent interaction with collagens is highly critical for adherence in the host and, furthermore, may play an important role in the establishment of disease.
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ABSTRACT Otitis media (OM) is among the leading diseases of childhood and is caused by opportunists that reside within the nasopharynx, such as Haemophilus influenzae and Moraxella catarrhalis. As with most airway infections, it is now clear that OM infections involve multiple organisms. This study addresses the hypothesis that polymicrobial infection alters the course, severity, and/or treatability of OM disease. The results clearly show that coinfection with H. influenzae and M. catarrhalis pro- motes the increased resistance of biofilms to antibiotics and host clearance. Using H. influenzae mutants with known biofilm defects, these phenotypes were shown to relate to biofilm maturation and autoinducer-2 (AI-2) quorum signaling. In support of the latter mechanism, chemically synthesized AI-2 (dihydroxypentanedione [DPD]) promoted increased M. catarrhalis biofilm formation and resistance to antibiotics. In the chinchilla infection model of OM, polymicrobial infection promoted M. catarrha- lis persistence beyond the levels seen in animals infected with M. catarrhalis alone. Notably, no such enhancement of M. ca- tarrhalis persistence was observed in animals infected with M. catarrhalis and a quorum signaling-deficient H. influenzae luxS mutant strain. We thus conclude that H. influenzae promotes M. catarrhalis persistence within polymicrobial biofilms via inter- species quorum signaling. AI-2 may therefore represent an ideal target for disruption of chronic polymicrobial infections. More- over, these results strongly imply that successful vaccination against the unencapsulated H. influenzae strains that cause airway infections may also significantly impact chronic M. catarrhalis disease by removing a reservoir of the AI-2 signal that promotes M. catarrhalis persistence within biofilm.
Secondly according to many reports, Moraxella catarrhalis incidence is more in individuals aged above 60 years old (Boyle et al., 1991; and Chin et al., 1993). Study of respiratory isolates from a hospital in Texas found that 81% of patients with M. catarrhalis were over 55 years (Chang et al., 2001). The short-term mortality in some patient categories is as high as 45% and most patients are elderly (older than 65 years) (Verduine et al., 2002). The age of patient having M. catarrhalis in this study was 58 and 67; this was coinciding with above mentioned reports. Studies have shown that beta-lactamase producing M. catarrhalis have increasingly been isolated as clinically significant isolates. Prior to 1977 only 4% of M. catarrhalis were resistant to penicillin but in 1985 others studies showed that 86.7% of a sample of 53 strains elaborated beta-lactamase and this trend seems to be increasing (Verduin et al., 2002).
We appreciate that the validity of many of the MIC interpretive criteria for M. catarrhalis is preliminary and unconfirmed. For the determination of breakpoints for an antimicrobial against a pathogen or group of pathogens, ideally reliable data are required from studies of the in vitro activity, the pharmacodynamics of the antimicrobial, and the in vivo efficacy rates from prospective clin- ical outcome studies (33). Unfortunately, reliable clinical out- come data on effective antimicrobial agents are scarce and are insufficient to draw conclusions about eradication rates. Further- more, target pharmacokinetic/pharmacodynamic values for mac- rolides, tetracyclines, rifampin, aminoglycosides, or folate antag- onists have not been uniformly accepted, As a consequence, we have selected MIC interpretive criteria mostly from Haemophilus influenzae, given the similarity of its clinical conditions to those of Haemophilus spp. in which M. catarrhalis is found. However, we believe the use of Haemophilus-derived breakpoints for the mac- rolides is inappropriate because the intrinsic activity of macrolides is substantially greater against Moraxella. Instead, we elected to use the CO WT values found in this study for this class of agents.
Moraxella catarrhalis is a significant cause of diseases of the upper airways, ear and lungs   -. Collectively, these diseases rank as significant causes of morbidity and mortality that are associated with treat- ment failure . Biofilm formation is linked to varying extents with each of these diseases    . To survive in diverse host environments M. catarrhalis must be able to grow both aerobically and anaerobically. Studies with Neisseria gonorrhoeae and Pseudomonas spp., in model biofilms systems, have shown that bio- films in aerobic environments have areas where the oxygen threshold is sufficiently low that the organism tran- sitions to anaerobic respiration, enabled by the elevated levels of nitrate from oxidation of nitric oxide produced during the inflammatory process  -. Although it is known that pathogens growing anaerobically typ- ically exhibit alterations in antimicrobial susceptibility (less susceptible), clinical laboratory testing of most bac- teria, including M. catarrhalis, is performed aerobically  . With the newly developed medium, the anae- robic MBC measured was similar to that determined either aerobically or in the presence of increased CO 2 levels,
efficiency when the same DNA was mixed with DNA from NPSs devoid of M. catarrhalis. The specificity of the reaction was further confirmed by the lack of amplification of DNAs from other Moraxella species, nontypeable Haemophilus influenzae, H. influenzae type b, Streptococcus pneumoniae, Streptococcus oralis, Streptococcus pyo- genes, Bordetella pertussis, Corynebacterium diphtheriae, and various Neisseria species. The assay applied to NPSs from 184 patients with respiratory tract infections performed with a sensitivity of 100% and a specificity of up to 98% compared to the culture results. The numbers of M. catarrhalis organisms detected by real-time PCR correlated with the numbers detected by semiquantitative culture. This real-time PCR assay targeting the copB outer membrane protein gene provided a sensitive and reliable means for the rapid detection and quantifica- tion of M. catarrhalis in NPSs; may serve as a tool to study changes in the amounts of M. catarrhalis during lower respiratory tract infections or following vaccination against S. pneumoniae, H. influenzae, or N. menin- gitidis; and may be applied to other clinical samples.
Nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis in 226 children in different settings (in a cre`che [day care center], in an orphanage, and at home) during two seasons (winter and spring) was studied. The rates of carriage of S. pneumoniae and H. influenzae were markedly higher in the cre`che and in the orphanage than in the home setting (e.g., 56.5, 63.3, and 25.9%, respectively, for S. pneumoniae in winter). Approximately 80% of the S. pneumoniae isolates identified in the cre`che and in the orphanage belonged to the serotypes represented in the seven-valent pneumococcal vaccine, and 4.4% of the children were colonized by H. influenzae type b. Almost all H. influenzae isolates were fully susceptible to the antimicrobial agents tested, and only five (3.6%) produced ␤ -lactamase; in contrast, 100% of the M. catarrhalis isolates were ␤ -lactamase positive. Among S. pneumoniae isolates, 36.2% were nonsuscep- tible to penicillin (PNSP) and 11.8% were fully resistant to penicillin (PRP). All PNSP isolates were obtained from children at the cre`che and at the orphanage but not among children brought up at home, and all PRP isolates showed a multiresistant phenotype. Colonization by PRP isolates correlated well with prior treatment with ␤ -lactams. For the majority of children colonized at both sampling times, strain replacement of S. pneumoniae and H. influenzae was observed; long-term colonization by a single strain was rare.
ABSTRACT Otitis media (OM) is often polymicrobial, with nontypeable Haemophilus inﬂuenzae (NTHI) and Moraxella catarrhalis (Mcat) frequently cocultured from clinical specimens. Bacterial bioﬁlms in the middle ear contribute to the chronicity and re- currence of OM; therefore, strategies to disrupt bioﬁlms are needed. We have fo- cused our vaccine development efforts on the majority subunit of NTHI type IV pili, PilA. Antibodies against a recombinant, soluble form of PilA (rsPilA) both disrupt and prevent the formation of NTHI bioﬁlms in vitro. Moreover, immunization with rsPilA prevents and resolves NTHI-induced experimental OM. Here, we show that antibod- ies against rsPilA also prevent and disrupt polymicrobial bioﬁlms. Dual-species bio- ﬁlms formed by NTHI and Mcat at temperatures that mimic the human nasopharynx (34°C) or middle ear (37°C) were exposed to antiserum against either rsPilA or the OMP P5 adhesin of NTHI. NTHI ⫹ Mcat bioﬁlm formation was signiﬁcantly inhibited by antiserum directed against both adhesin proteins at either temperature. However, only anti-rsPilA disrupted NTHI ⫹ Mcat preestablished bioﬁlms at either temperature and actively dispersed both NTHI and Mcat via interspecies quorum signaling. Newly released NTHI and Mcat were signiﬁcantly more susceptible to killing by antibiotics. Taken together, these results revealed new opportunities for treatment of bioﬁlm- associated diseases via a strategy that combines vaccine-induced antibody-mediated bioﬁlm dispersal with traditional antibiotics, at a signiﬁcantly reduced dosage to ex- ploit the newly released, antibiotic-sensitive phenotype. Combined, our data strongly support the utility of rsPilA both as a preventative and as a therapeutic vaccine anti- gen for polymicrobial OM due to NTHI and Mcat.
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Moraxella catarrhalis is a gram-negative bacterium that infects hu- mans exclusively (de Vries et al., 2009). Up to 80% of children under 2 years old carry M. catarrhalis: this rate drops to 10% for older children and to 5% for healthy adults, and increases again in the elderly (Aebi, 2011). Although for many years it was considered to be only a com- mensal, M. catarrhalis is now classed as a pathogen. After Streptococcus pneumonia and Heamophilus influenza, it is the third most common pa- thogen causing acute otitis media in children (Verduin et al., 2002). In adults with chronic obstructive pulmonary disease, M. catarrhalis in- duces not only upper but also lower respiratory tract infections, causing infections as severe as septicaemia, meningitis or endocarditis in
M. catarrhalis is an important pathogen in respiratory tract infections in children, but bacteremia is rare . Several recent reports revealed that previously healthy im- munocompetent patients developed Moraxella bacteremia at a constant rate [24–27]. In the current study, however, only one previously healthy child developed bacteremia due to M. catarrhalis and the remaining seven patients had underlying disease. A previous report described 11 cases of bacteremia due to M. catarrhalis and noted that it should be considered in febrile children with underlying immunodeficiency and upper respiratory tract infection . Ioannidis et al. noted that nearly 30 % of patients with M. catarrhalis bacteremia had underlying respiratory fac- tors including tracheostomy or dependence on mechanical ventilation, and acute respiratory infections such as viral pneumonia . The authors also described an association with chronic neurological debilities as one of the predis- posing factors . Similarly, we found that a quarter of the patients had underlying respiratory diseases, and three out of eight patients had chronic neurological problems. More specifically, our study highlights the association of medical devices, particularly trans-nasal devices, as inde- pendent factors associated with bacteremia due to M. cat- arrhalis compared with S. pneumoniae or H. influenzae. Most isolates of M. catarrhalis produce beta-lactamases in contrast to S. pneumoniae which acquire modest ampi- cillin resistance through modification of the penicillin binding proteins. Our findings suggests that modification of empiric coverage to cover penicillinase producing M. catarrhalis is a consideration for patients with underlying disorders with trans-nasal devices who develop respiratory tract infections.
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Moraxella catarrhalis, a gram-negative diplococcus, is consid- ered a significant cause of acute otitis media in children and lower respiratory infections in adults with chronic obstructive pulmonary disease (COPD) (12, 21, 29). A number of putative virulence factors have been described for M. catarrhalis (8, 11, 12, 17, 20), including a surface-exposed lipooligosaccharide (LOS) (6, 18, 23, 32). Structural and serological studies with M. catarrhalis have described only three different LOS serotypes (termed A, B, and C), which vary in length and content of the oligosaccharide branches (3–5, 13, 15, 28). One serological study by Vaneechoutte et al. grouped clinical isolates into serotypes A (60%), B (30%), and C (5%), with 5% of the strains unidentified (28). That has been the only study to in- vestigate the prevalence of specific M. catarrhalis LOS sero- types in the population. The difficulties with serological deter- minations of M. catarrhalis LOS expression are the limited quantities of antibodies, the absolute requirement for purified sample, and the potential for cross-reactivity between sero- types A and C (13, 24, 25).
According to studies based on bacterial cultures of middle ear fluids, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis have been the most common pathogens in acute otitis media. However, bacterial culture can be affected by reduced viability or suboptimal growth of bacteria. PCR detects bacterial DNA from samples with greater sensitivity than cul- ture. In the present study, we analyzed the middle ear pathogens with both conventional culture and semiquantitative real-time PCR in 90 middle ear fluid samples obtained from children aged 5 to 42 months during acute otitis media episodes. Samples were tested for the presence of S. pneumoniae, H. influenzae, M. catarrhalis, Alloiococcus otitidis, Staphylococcus aureus, and Pseu- domonas aeruginosa. One or more bacterial pathogens were detected in 42 (47%) samples with culture and in 69 (77%) samples with PCR. According to PCR analysis, M. catarrhalis results were positive in 42 (47%) samples, H. influenzae in 30 (33%), S. pneumoniae in 27 (30%), A. otitidis in 6 (6.7%), S. aureus in 5 (5.6%), and P. aeruginosa in 1 (1.1%). Multibacterial etiology was seen in 34 (38%) samples, and M. catarrhalis was detected in most (85%) of those cases. Fifteen signals for M. catarrhalis were strong, suggesting a highly probable etiological role of the pathogen. In conclusion, even though M. catarrhalis is often a part of mixed flora in acute otitis media, a considerable proportion of cases may be primarily attributable to this pathogen.
Cells from a 100-l aliquot of sample were lysed in 200 l of 50 mM phosphate buffer, pH 6.7, containing 1 mg/ml lysozyme, 0.075 mg/ml mutanolysin, and 2 mg/ml proteinase K and incu- bated at 56°C for 45 min. An additional 2 mg/ml proteinase K and 1% SDS were added, and then cells were incubated at 56°C for 10 min. DNA was extracted and purified into 100 l elution buffer using the QIAmp DNA minikit (Qiagen). DNA for standard curves was extracted from S. pneumoniae ATCC 6305, H. influen- zae F412 (kindly provided by Cynthia Whitchurch, University of Technology, Sydney, Australia), S. aureus ATCC 29213, and M. catarrhalis ATCC 8176. We developed two quantitative duplex PCR assays, one to detect S. pneumoniae and S. aureus and another to detect H. influenzae and M. catarrhalis. S. pneumoniae was de- tected using previously published primers and probes (30). Prim- ers for S. aureus detection were modified for use with a previously published probe (6) for enhanced sensitivity. Sequence alignment of M. catarrhalis copB from 14 available GenBank entries revealed that published probes (9, 30) hybridize to a variable region of the gene, so a new primer/probe set was designed to target a conserved region of this gene. This qPCR was coupled with an assay for H. influenzae that was developed to detect both typeable and non- typeable H. influenzae but not the closely related Haemophilus haemolyticus (38). Two microliters of DNA was used in each of two duplex qPCRs performed with Brilliant III Ultra-Fast QPCR master mix (Agilent Technologies) on a Stratagene Mx3005 real- time PCR instrument with an initial activation of 95°C for 3 min
The evaluation of the discriminatory power of SpeI with respect to that of NotI was performed on 35 nonrepeated isolates from different episodes of 31 patients with COPD that presented a complete diges- tion for NotI. As shown in Fig. 3, the discriminatory power of NotI (19 genotypes) is slightly superior to that of SpeI (14 genotypes). A previous study published by Vu-Thien et al. (13) on 11 M. catarrhalis isolates suggested that although NotI had the most discriminatory power, SpeI patterns were also reliable. Our study, performed on 35 independent isolates, proves that the difference between both restric- tion enzymes is minimal (Fig. 3) and, probably, the importance of a correct restriction of all the samples outweighs the small difference in discriminatory power.
Forty-eight individual M. catarrhalis colonies were sequenced from the 35 samples (23 samples had a single colony, 11 samples had two colonies, and one sample had three colonies sequenced). The diversity between samples was very large with 25 different M. catarrhalis MLST types (12 of which have not been described previously) identified from the 35 samples (all 48 genome sequences have been deposited in NCBI GenBank as BioProject PRJNA488991). Of the 12 samples in which multiple colonies were available for sequencing, only one contained two different strains as defined by MLST type. A phylogenetic analysis com- paring the 48 strains sequenced in this work with the 52 M. catarrhalis genomes currently available from GenBank is shown in Figure 1; the cladogram, which is based upon accessory genome content, shows that all of the strains identified in this work fell into clades alongside previously sequenced genomes. Changes in M. catarrhalis strain were observed between stable visits, from stable to exacerbation and vice-a-versa, and between exacerbation visits. Persis- tence of an M. catarrhalis strain was also observed from stable to exacerbation and between exacerbation visits. Between subjects, only three of the 25 MLST groups were shared (ST-41, ST-46, and ST-70), whereas 22 were unique within subjects. For the five subjects with more than one sample and at least one stable sample taken, the changes in the MLST of M. catarrhalis strains identified over time are shown in Figure 2.
Nasopharyngeal carriage of Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis was studied in 259 children attending day care centers (DCC) in Amsterdam, The Netherlands, and in 276 control children. The DCC children were sampled a second time after 4 weeks. Carriage rates for DCC children and controls were 58 and 37% for S. pneumoniae, 37 and 11% for H. influenzae, and 80 and 48% for M. catarrhalis, respectively. No increased antibiotic resistance rates were found in strains isolated from DCC children. All H. influenzae isolates were typed by random amplified polymorphic DNA (RAPD) analysis. Evidence for frequent transmission of H. influenzae strains within DCC was found. In the control group only two isolates (4%) displayed identical RAPD types versus 38% of strains from DCC children. Colonization with H. influenzae appeared to be short-lived in these children; more than half of the children harboring H. influenzae in the first sample were negative in the second sample, whereas most children still positive in the second sample had a different genotype than in the first sample. Of the newly acquired strains in the second sample, 40% were identical to a strain that had been found in a child in the same DCC in the first sample. DCC are to be considered epidemiological niches with a high potential for the spread of pathogenic microorganisms.
ABSTRACT Little is known about interactions between nontypeable Haemophilus inﬂuenzae, Moraxella catarrhalis, Streptococcus pneumoniae, and Pseudomonas aerugi- nosa in the lower respiratory tract in chronic obstructive pulmonary disease (COPD) patients. We characterized colonization by these four bacterial species, determined species-speciﬁc interactions, and estimated the effects of host factors on bacterial colonization among COPD patients. We conducted a prospective cohort study in veterans with COPD that involved monthly clinical assessment and sputum cultures with an average duration of follow-up of 4.5 years. Cultures were used for bacterial identiﬁcation. We analyzed bacterial interactions using generalized linear mixed models after controlling for clinical and demographic variables. The outcomes of in- terest were the relationships between bacteria based on clinical status (stable or ex- acerbation). One hundred eighty-one participants completed a total of 8,843 clinic visits, 30.8% of which had at least one of the four bacteria isolated. H. inﬂuenzae was the most common bacterium isolated (14.4%), followed by P. aeruginosa (8.1%). In adjusted models, S. pneumoniae colonization was positively associated with H. in- ﬂuenzae colonization (odds ratio [OR], 2.79; 95% conﬁdence interval [CI], 2.03 to 3.73). We identiﬁed negative associations between P. aeruginosa and H. inﬂuenzae (OR, 0.15; 95% CI, 0.10 to 0.22) and P. aeruginosa and M. catarrhalis (OR, 0.51; 95% CI, 0.35 to 0.75). Associations were similar during stable and exacerbation visits. Re- cent antimicrobial therapy was associated with a lower prevalence of S. pneumoniae, H. inﬂuenzae, and M. catarrhalis, but not P. aeruginosa. Our ﬁndings support the presence of speciﬁc interspecies interactions between common bacteria in the lower respiratory tracts of COPD patients. Further work is necessary to elucidate the mech- anisms of these complex interactions that shift bacterial species.
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Sixty five Bacillus thuringiensis strains were isolated from soils of the western ghats of Maharashtra. From sixty five isolates of B. thuringiensis; ten B. thuringiensis strains were screened for their cry gene profile (cry2, cry3 and cry6) and capacity to express bacteriocin-like agents. B. thuringiensis isolate no.9, showed antagonistic activity towards Corynebacterium diphtheriae, Rothia dentocariosa, Moraxella catarrhalis, Neisseria polysaccharea, Staphylococcus aureus, Streptococcus pyogenes, and other Bacillus sp.; The partially purified bacteriocin (PPB) obtained from isolate no.9 by salt precipitation was studied by SDS-PAGE had an apparent Molecular weight of 43kDa. Effect of temperature and pH on activity of PPB was studied. This novel identified and characterized partially purified bacteriocin can be effective in control of human pathogen such as Coryne. diphtheriae it may play an interesting role in therapeutic science.