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1.
J Manag Care Spec Pharm ; 30(5): 456-464, 2024 May.
Article in English | MEDLINE | ID: mdl-38701031

ABSTRACT

BACKGROUND: The Defense Health Agency comprises more than 700 military medical, dental, and veterinary facilities and provides care to more than 9.6 million beneficiaries. As medication experts, pharmacists identify opportunities to optimize medication therapy, reduce cost, and increase readiness to support the Defense Health Agency's mission. The Tripler Pilot Project and the Army Polypharmacy Program were used to establish a staffing model of 1 clinical pharmacist for every 6,500 enrolled beneficiaries. No large-scale cost-benefit study within the military health care system has been done, which documents the number of clinical interventions and uses established cost-avoidance (CA) data, to determine the cost-benefit and return on investment (ROI) for clinical pharmacists working in the medical treatment facilities. OBJECTIVE: To validate the patient-centered medical home staffing model across the military health care system using the Tripler Pilot Project results to provide a cost-benefit analysis with an ROI. The secondary goal is to describe the interventions, staffing levels, and US Department of Defense-specific requirements impacting the provision of clinical pharmacy. METHODS: A retrospective analysis of 3 years of encounters by clinical pharmacists in which an intervention was documented in the Tri-Service Workflow (TSWF) form as part of the electronic health record was completed. The analysis used 6 steps to assign CA intervention types and to prevent duplication and overestimation of the ROI. The absolute number of clinical pharmacists was determined using workload criteria defined as at least 20 encounters per month for at least 3 months of each calendar year. The number of clinical pharmacist full-time employees (FTEs) was determined by dividing the number of total active months by 12 months. Attrition was calculated comparing the presence of a unique provider identification between calendar years. The ROI range was calculated by dividing the CA by the total cost of clinical pharmacists using the variables' raw and extrapolated CA based on percentage of documentation template usage and the active clinical pharmacist calculation (absolute and FTE-based). RESULTS: Between January 1, 2017, and December 31, 2019, a total of 1,069,846 encounters by clinical pharmacists were documented in the electronic health record. The TSWF Alternative Input Method form was used by pharmacists to document 616,942 encounters. Forty-three percent of TSWF documented encounters had at least 1 CA intervention. The absolute number of clinical pharmacists associated with a documented encounter in any medical treatment facility ranged from 404 in 2017 to 374 in 2018 and the clinical pharmacist FTEs ranged from 324 in 2017 to 314 in 2019. Annual attrition rates for clinical pharmacists ranged from 15% to 20% (58 to 81 clinical pharmacists) annually. The total CA range was $329,166,543-$534,014,494. The ROI range was between $2 and $4 per dollar spent. CONCLUSIONS: This analysis demonstrated that ambulatory care clinical pharmacists in the Military Health System bring value through a positive ROI. Our study also identified a potential shortage of clinical pharmacists within the Air Force and Navy branches impacting medication management. This can have a negative impact on the readiness of service members, one of the leading priorities of the US Department of Defense.


Subject(s)
Cost-Benefit Analysis , Pharmacists , Humans , Pharmacists/economics , Pilot Projects , Retrospective Studies , Pharmacy Service, Hospital/economics , Pharmacy Service, Hospital/organization & administration , Male , United States , Professional Role , Female , Patient-Centered Care/economics , Middle Aged , Adult , Military Health Services/economics , Military Health/economics
2.
Mil Med ; 189(7-8): e1577-e1587, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38394445

ABSTRACT

INTRODUCTION: Medications play a critical role supporting the health of military service members. Little is known about the broad use of medications prescribed to this population. Active duty service members (ADSMs), while often younger and having fewer diagnosed comorbid conditions, face unique health challenges that benefit from pharmacotherapy. Understanding prescribing patterns is instrumental to illuminate potential areas for research and to guide education so that military health care professionals can maintain competency, improve outcomes, and support medical readiness. This study aimed to characterize commonly dispensed medications among ADSMs and to compare these prescriptions with those of the general population. MATERIALS AND METHODS: A retrospective, cross-sectional analysis using data extracted contained in the Military Health System Information Platform focused on ADSMs who consulted with a clinical pharmacist during the 2019 fiscal year. Descriptive statistics were used to summarize patient and prescription data. The 100 most frequently prescribed medications and 20 most frequently prescribed therapeutic classes were identified. Analyses were performed using Statistical Analysis System (SAS) software, and a non-metric multidimensional scaling plot was generated in R to illustrate the relationships between the 20 most frequently used therapeutic classes and the branches of service. RESULTS: The study analyzed 719,788 prescriptions for 30,012 service members, revealing a high prescription rate for pain, inflammation, and psychiatric condition treatments. Antidepressants and nonsteroidal anti-inflammatory drugs were among the most commonly prescribed across all military branches. Some medication uses varied, which may indicate distinct needs within different service branches. CONCLUSIONS: Understanding medication patterns among ADSMs may be able to help health care professionals proactively address pharmacological challenges and optimize pharmaceutical use in this unique population. This knowledge can also aid in the development of training modules focused on medication side effects, interactions, counseling, and implications on military deployment for the most commonly used medications. Future examination into prescribing cascades and medication use related to proton-pump inhibitors, docusate, benzonatate, and muscle relaxants may identify opportunities to provide better care or lower cost.


Subject(s)
Military Personnel , Humans , Cross-Sectional Studies , Military Personnel/statistics & numerical data , Military Personnel/psychology , Male , Adult , Retrospective Studies , Female , Middle Aged , Pharmacists/statistics & numerical data , Pharmacists/trends , Practice Patterns, Pharmacists'/statistics & numerical data , Practice Patterns, Pharmacists'/trends , Practice Patterns, Physicians'/statistics & numerical data , Practice Patterns, Physicians'/trends , Practice Patterns, Physicians'/standards , Drug Prescriptions/statistics & numerical data , United States
3.
Infect Immun ; 84(10): 2982-94, 2016 10.
Article in English | MEDLINE | ID: mdl-27481245

ABSTRACT

Neisseria gonorrhoeae successfully overcomes host strategies to limit essential nutrients, termed nutritional immunity, by production of TonB-dependent transporters (TdTs)-outer membrane proteins that facilitate nutrient transport in an energy-dependent manner. Four gonococcal TdTs facilitate utilization of iron or iron chelates from host-derived proteins, including transferrin (TbpA), lactoferrin (LbpA), and hemoglobin (HpuB), in addition to xenosiderophores from other bacteria (FetA). The roles of the remaining four uncharacterized TdTs (TdfF, TdfG, TdfH, and TdfJ) remain elusive. Regulatory data demonstrating that production of gonococcal TdfH and TdfJ are unresponsive to or upregulated under iron-replete conditions led us to evaluate the role of these TdTs in the acquisition of nutrients other than iron. In this study, we found that production of gonococcal TdfH is both Zn and Zur repressed. We also found that TdfH confers resistance to calprotectin, an immune effector protein highly produced in neutrophils that has antimicrobial activity due to its ability to sequester Zn and Mn. We found that TdfH directly binds calprotectin, which enables gonococcal Zn accumulation in a TdfH-dependent manner and enhances bacterial survival after exposure to neutrophil extracellular traps (NETs). These studies highlight Zn sequestration by calprotectin as a key functional arm of NET-mediated killing of gonococci. We demonstrate for the first time that N. gonorrhoeae exploits this host strategy in a novel defense mechanism, in which TdfH production hijacks and directly utilizes the host protein calprotectin as a zinc source and thereby evades nutritional immunity.


Subject(s)
Bacterial Outer Membrane Proteins/physiology , Extracellular Traps/metabolism , Gonorrhea/immunology , Host-Parasite Interactions/physiology , Leukocyte L1 Antigen Complex/metabolism , Neisseria gonorrhoeae/immunology , Neutrophils/metabolism , Bacterial Outer Membrane Proteins/metabolism , Humans , Immunity, Cellular/physiology , Neisseria gonorrhoeae/growth & development , Neisseria gonorrhoeae/metabolism , Neutrophils/parasitology , Zinc Sulfate/metabolism
4.
J Infect Dis ; 212(2): 316-24, 2015 Jul 15.
Article in English | MEDLINE | ID: mdl-25605868

ABSTRACT

Acute gonorrhea is characterized by neutrophilic inflammation that is insufficient to clear Neisseria gonorrhoeae. Activated neutrophils release extracellular traps (NETs), which are composed of chromatin and decorated with antimicrobial proteins. The N. gonorrhoeae NG0969 open reading frame contains a gene (nuc) that encodes a putatively secreted thermonuclease (Nuc) that contributes to biofilm remodeling. Here, we report that Nuc degrades NETs to help N. gonorrhoeae resist killing by neutrophils. Primary human neutrophils released NETs after exposure to N. gonorrhoeae, but NET integrity declined over time with Nuc-containing bacteria. Recombinant Nuc and conditioned medium from Nuc-containing N. gonorrhoeae degraded human neutrophil DNA and NETs. NETs were found to have antimicrobial activity against N. gonorrhoeae, and Nuc expression enhanced N. gonorrhoeae survival in the presence of neutrophils that released NETs. We propose that Nuc enables N. gonorrhoeae to escape trapping and killing by NETs during symptomatic infection, highlighting Nuc as a multifunctional virulence factor for N. gonorrhoeae.


Subject(s)
Bacterial Proteins/physiology , Extracellular Traps/microbiology , Micrococcal Nuclease/physiology , Neisseria gonorrhoeae/enzymology , Neutrophils/immunology , Cells, Cultured , Host-Pathogen Interactions , Humans , Microbial Viability , Neisseria gonorrhoeae/immunology , Neutrophil Activation , Neutrophils/microbiology
5.
Infect Immun ; 83(1): 239-46, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25348637

ABSTRACT

Nontypeable Haemophilus influenzae (NTHI) is a common commensal and opportunistic pathogen of the human airways. For example, NTHI is a leading cause of otitis media and is the most common cause of airway infections associated with chronic obstructive pulmonary disease (COPD). These infections are often chronic/recurrent in nature and involve bacterial persistence within biofilm communities that are highly resistant to host clearance. Our previous work has shown that NTHI within biofilms has increased expression of factors associated with oxidative stress responses. The goal of this study was to define the roles of catalase (encoded by hktE) and a bifunctional peroxiredoxin-glutaredoxin (encoded by pdgX) in resistance of NTHI to oxidants and persistence in vivo. Isogenic NTHI strain 86-028NP mutants lacking hktE and pdgX had increased susceptibility to peroxide. Moreover, these strains had persistence defects in the chinchilla infection model for otitis media, as well as in a murine model for COPD. Additional work showed that pdgX and hktE were important determinants of NTHI survival within neutrophil extracellular traps (NETs), which we have shown to be an integral part of NTHI biofilms in vivo. Based on these data, we conclude that catalase and peroxiredoxin-glutaredoxin are determinants of bacterial persistence during chronic/recurrent NTHI infections that promote bacterial survival within NETs.


Subject(s)
Catalase/metabolism , Drug Tolerance , Glutaredoxins/metabolism , Haemophilus influenzae/drug effects , Haemophilus influenzae/enzymology , Oxidants/toxicity , Peroxiredoxins/metabolism , Animals , Catalase/genetics , Chinchilla , Disease Models, Animal , Gene Deletion , Glutaredoxins/genetics , Haemophilus influenzae/genetics , Microbial Viability/drug effects , Otitis Media/microbiology , Oxidants/metabolism , Peroxiredoxins/genetics
6.
Mol Microbiol ; 82(4): 836-50, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21923771

ABSTRACT

Nontypeable Haemophilus influenzae (NTHI) is a respiratory commensal and opportunistic pathogen, which persists within biofilms on airway mucosal surfaces. For many species, biofilm formation is impacted by quorum signalling. Our prior work shows that production of autoinducer-2 (AI-2) promotes biofilm development and persistence for NTHI 86-028NP. NTHI 86-028NP encodes an ABC transporter annotated as a ribose transport system that includes a protein (RbsB) with similarity to the Escherichia coli LsrB and Aggregatibacter actinomycetemcomitans RbsB proteins that bind AI-2. In this study, inactivation of rbsB significantly reduced uptake of AI-2 and the AI-2 precursor dihydroxypentanedione (DPD) by NTHI 86-028NP. Moreover, DPD uptake was not competitively inhibited by ribose or other pentose sugars. Transcript levels of rbsB increased in response to DPD and as bacteria approached stationary-phase growth. The NTHI 86-028NP rbsB mutant also formed biofilms with significantly reduced thickness and total biomass and reduced surface phosphorylcholine, similar to a luxS mutant. Infection studies revealed that loss of rbsB impaired bacterial persistence in the chinchilla middle ear, similar to our previous results with luxS mutants. Based on these data, we conclude that in NTHI 86-028NP, RbsB is a LuxS/AI-2 regulated protein that is required for uptake of and response to AI-2.


Subject(s)
ATP-Binding Cassette Transporters/metabolism , Haemophilus influenzae/physiology , Quorum Sensing , Signal Transduction , ATP-Binding Cassette Transporters/genetics , Animals , Biofilms/growth & development , Biomass , Chinchilla , Disease Models, Animal , Ear, Middle/microbiology , Gene Deletion , Gene Expression Profiling , Haemophilus Infections/microbiology , Haemophilus influenzae/genetics , Homoserine/analogs & derivatives , Homoserine/metabolism , Lactones/metabolism , Pentanes/metabolism
7.
Infect Immun ; 79(8): 3087-95, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21646454

ABSTRACT

Biofilms contribute to Pseudomonas aeruginosa persistence in a variety of diseases, including cystic fibrosis, burn wounds, and chronic suppurative otitis media. However, few studies have directly addressed P. aeruginosa biofilms in vivo. We used a chinchilla model of otitis media, which has previously been used to study persistent Streptococcus pneumoniae and Haemophilus influenzae infections, to show that structures formed in vivo are biofilms of bacterial and host origin within a matrix that includes Psl, a P. aeruginosa biofilm polysaccharide. We evaluated three biofilm and/or virulence mediators of P. aeruginosa known to affect biofilm formation in vitro and pathogenesis in vivo--bis-(3',5')-cyclic dimeric GMP (c-di-GMP), flagella, and quorum sensing--in a chinchilla model. We show that c-di-GMP overproduction has a positive impact on bacterial persistence, while quorum sensing increases virulence. We found no difference in persistence attributed to flagella. We conclude from these studies that a chinchilla otitis media model provides a means to evaluate pathogenic mediators of P. aeruginosa and that in vitro phenotypes should be examined in multiple infection systems to fully understand their role in disease.


Subject(s)
Biofilms/growth & development , Gene Expression Regulation, Bacterial , Otitis Media/veterinary , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/pathogenicity , Animals , Chinchilla , Chronic Disease , Cyclic GMP/analogs & derivatives , Cyclic GMP/metabolism , Disease Models, Animal , Humans , Otitis Media/microbiology , Otitis Media/pathology , Pseudomonas Infections/pathology , Pseudomonas aeruginosa/metabolism , Quorum Sensing , Rodent Diseases/microbiology , Rodent Diseases/pathology , Virulence
8.
J Infect Dis ; 203(4): 549-55, 2011 Feb 15.
Article in English | MEDLINE | ID: mdl-21220774

ABSTRACT

BACKGROUND: Otitis media, for which antibiotic treatment failure is increasingly common, is a leading pediatric public health problem. METHODS: In vitro and in vivo studies using the chinchilla model of otitis media were performed using a ß-lactamase-producing strain of nontypeable Haemophilus influenzae (NTHi 86-028NP) and an isogenic mutant deficient in ß-lactamase production (NTHi 86-028NP bla) to define the roles of biofilm formation and ß-lactamase production in antibiotic resistance. Coinfection studies were done with Streptococcus pneumoniae to determine if NTHi provides passive protection by means of ß-lactamase production, biofilm formation, or both. RESULTS: NTHi 86-028NP bla was resistant to amoxicillin killing in biofilm studies in vitro; however, it was cleared by amoxicillin treatment in vivo, whereas NTHi 86-028NP was unaffected in either system. NTHi 86-028NP protected pneumococcus in vivo in both the effusion fluid and bullar homogenate. NTHi 86-028NP bla and pneumococcus were both recovered from the surface-associated bacteria of amoxicillin-treated animals; only NTHi 86-028NP bla was recovered from effusion. CONCLUSIONS: Based on these studies, we conclude that NTHi provides passive protection for S. pneumoniae in vivo through 2 distinct mechanisms: production of ß-lactamase and formation of biofilm communities.


Subject(s)
Anti-Bacterial Agents/pharmacology , Haemophilus influenzae/metabolism , Streptococcus pneumoniae/drug effects , beta-Lactam Resistance , beta-Lactamases/biosynthesis , beta-Lactams/pharmacology , Animals , Anti-Bacterial Agents/therapeutic use , Biofilms/growth & development , Chinchilla , Disease Models, Animal , Haemophilus Infections/complications , Haemophilus Infections/microbiology , Haemophilus influenzae/physiology , Microbial Viability , Otitis Media/drug therapy , Otitis Media/microbiology , Pneumococcal Infections/complications , Pneumococcal Infections/microbiology , Streptococcus pneumoniae/growth & development , beta-Lactams/therapeutic use
9.
Infect Immun ; 79(1): 431-8, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20956567

ABSTRACT

Nontypeable Haemophilus influenzae (NTHI) is a leading cause of otitis media infections, which are often chronic and/or recurrent in nature. NTHI and other bacterial species persist in vivo within biofilms during otitis media and other persistent infections. These biofilms have a significant host component that includes neutrophil extracellular traps (NETs). These NETs do not mediate clearance of NTHI, which survives within NET structures by means of specific subpopulations of lipooligosaccharides on the bacterial surface that are determinants of biofilm formation in vitro. In this study, the ability of NTHI and NTHI components to initiate NET formation was examined using an in vitro model system. Both viable and nonviable NTHI strains were shown to promote NET formation, as did preparations of bacterial DNA, outer membrane proteins, and lipooligosaccharide (endotoxin). However, only endotoxin from a parental strain of NTHI exhibited equivalent potency in NET formation to that of NTHI. Additional studies showed that NTHI entrapped within NET structures is resistant to both extracellular killing within NETs and phagocytic killing by incoming neutrophils, due to oligosaccharide moieties within the lipooligosaccharides. Thus, we concluded that NTHI elicits NET formation by means of multiple pathogen-associated molecular patterns (most notably endotoxin) and is highly resistant to killing within NET structures. These data support the conclusion that, for NTHI, formation of NET structures may be a persistence determinant by providing a niche within the middle-ear chamber.


Subject(s)
Haemophilus Infections/microbiology , Haemophilus influenzae/classification , Haemophilus influenzae/physiology , Neutrophils/physiology , Animals , Bacterial Outer Membrane Proteins , Cells, Cultured , DNA, Bacterial , Humans , Lipopolysaccharides/metabolism , Male , Mice , Mice, Inbred Strains , Neutrophils/ultrastructure , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism
10.
mBio ; 1(3)2010 Jul 06.
Article in English | MEDLINE | ID: mdl-20802829

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 promotes 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. catarrhalis persistence beyond the levels seen in animals infected with M. catarrhalis alone. Notably, no such enhancement of M. catarrhalis 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 interspecies quorum signaling. AI-2 may therefore represent an ideal target for disruption of chronic polymicrobial infections. Moreover, 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.


Subject(s)
Haemophilus Infections/microbiology , Haemophilus influenzae/pathogenicity , Moraxella catarrhalis/pathogenicity , Moraxellaceae Infections/microbiology , Otitis Media/microbiology , Quorum Sensing , Animals , Anti-Bacterial Agents/therapeutic use , Biofilms/drug effects , Chinchilla , Drug Resistance, Bacterial , Haemophilus Infections/drug therapy , Haemophilus influenzae/drug effects , Haemophilus influenzae/genetics , Haemophilus influenzae/physiology , Humans , Moraxella catarrhalis/drug effects , Moraxella catarrhalis/genetics , Moraxella catarrhalis/physiology , Moraxellaceae Infections/drug therapy , Otitis Media/drug therapy , Quorum Sensing/drug effects
11.
J Infect Dis ; 202(7): 1068-75, 2010 Oct 01.
Article in English | MEDLINE | ID: mdl-20715928

ABSTRACT

BACKGROUND: Otitis media is an extremely common pediatric infection and is mostly caused by bacteria that are carried within the nasopharyngeal microbiota. It is clear that most otitis media cases involve simultaneous infection with multiple agents. METHODS: Chinchillas were infected with nontypeable Haemophilus influenzae, Streptococcus pneumoniae, or a combination of both organisms, and the course of disease was compared. In vitro experiments were also performed to address how coinfection impacts biofilm formation. RESULTS: The incidence of systemic disease was reduced in coinfected animals, compared with those infected with pneumococcus alone. Pneumococci were present within surface-attached biofilms in coinfected animals, and a greater proportion of translucent colony type was observed in the coinfected animals. Because this colony type has been associated with pneumococcal biofilms, the impact of coinfection on pneumococcal biofilm formation was investigated. The results clearly show enhanced biofilm formation in vitro by pneumococci in the presence of H. influenzae. CONCLUSIONS: Based on these data, we conclude that coinfection with H. influenzae facilitates pneumococcal biofilm formation and persistence on the middle ear mucosal surface. This enhanced biofilm persistence correlates with delayed emergence of opaque colony variants within the bacterial population and a resulting decrease in systemic infection.


Subject(s)
Biofilms/growth & development , Haemophilus Infections/microbiology , Haemophilus influenzae/growth & development , Otitis Media/microbiology , Pneumococcal Infections/microbiology , Streptococcus pneumoniae/growth & development , Animals , Chinchilla , Disease Models, Animal , Disease Progression , Haemophilus Infections/pathology , Humans , Pneumococcal Infections/pathology , Sepsis/prevention & control
12.
Infect Immun ; 77(9): 4081-91, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19564381

ABSTRACT

Nontypeable Haemophilus influenzae (NTHI) is an extremely common airway commensal which can cause opportunistic infections that are usually localized to airway mucosal surfaces. During many of these infections, NTHI forms biofilm communities that promote persistence in vivo. For many bacterial species, density-dependent quorum-signaling networks can affect biofilm formation and/or maturation. Mutation of luxS, a determinant of the autoinducer 2 (AI-2) quorum signal pathway, increases NTHI virulence in the chinchilla model for otitis media infections. For example, bacterial counts in middle-ear fluids and the severity of the host inflammatory response were increased in luxS mutants compared with parental strains. As these phenotypes are consistent with those that we have observed for biofilm-defective NTHI mutants, we hypothesized that luxS may affect NTHI biofilms. A luxS mutant was generated using the well-characterized NTHI 86-028NP strain and tested to determine the effects of the mutation on biofilm phenotypes in vitro and bacterial persistence and disease severity during experimental otitis media. Quantitation of the biofilm structure by confocal microscopy and COMSTAT analysis revealed significantly reduced biomass for NTHI 86-028NP luxS biofilms, which was restored by a soluble mediator in NTHI 86-028NP supernatants. Analysis of lipooligosaccharide moieties using an enzyme-linked immunosorbent assay and immunoblotting showed decreased levels of biofilm-associated glycoforms in the NTHI 86-028NP luxS strain. Infection studies showed that NTHI 86-028NP luxS had a significant persistence defect in vivo during chronic otitis media infection. Based on these data, we concluded that a luxS-dependent soluble mediator modulates the composition of the NTHI lipooligosaccharides, resulting in effects on biofilm maturation and bacterial persistence in vivo.


Subject(s)
Bacterial Proteins/physiology , Biofilms , Carbon-Sulfur Lyases/physiology , Haemophilus influenzae/physiology , Lipopolysaccharides/analysis , Animals , Chinchilla , Haemophilus influenzae/chemistry , Homoserine/analogs & derivatives , Homoserine/physiology , Lactones , Otitis Media/microbiology , Phosphorylcholine/analysis , Repetitive Sequences, Nucleic Acid
13.
J Innate Immun ; 1(3): 215-24, 2009.
Article in English | MEDLINE | ID: mdl-20375579

ABSTRACT

Nontypeable Haemophilus influenzae (NTHi) is a leading cause of acute and chronic otitis media, which are a major public health problem worldwide. The persistence of NTHi during chronic and recurrent otitis media infections involves multicellular biofilm communities formed within the middle-ear chamber. Bacterial biofilms resist immune clearance and antibiotic therapy due in part to encasement within a polymeric matrix. In this study, the contribution of biofilms to bacterial persistence in vivo and composition of the NTHi biofilm matrix during experimental otitis media were investigated. The presence of biofilms within the chinchilla middle-ear chamber was significantly correlated with increased bacterial load in middle-ear effusions and tissue. Examination of thin sections revealed polymorphonuclear cells within a DNA lattice containing elastase and histones, which is consistent with the definition of neutrophil extracellular traps. Viable multicellular biofilm communities with biofilm phenotypes were found within the DNA lattice throughout the biofilm. Further, NTHi was resistant to both phagocytic and extracellular neutrophil killing in vitro by means of lipooligosaccharide moieties that promote biofilm formation. These data support the conclusion that NTHi subverts neutrophil extracellular traps to persist in vivo. These data also indicate that a more inclusive definition for biofilms may be warranted.


Subject(s)
Biofilms/growth & development , Cellular Structures/microbiology , Haemophilus influenzae/growth & development , Neutrophils/microbiology , Neutrophils/ultrastructure , Otitis Media/microbiology , Acute Disease , Animals , Chinchilla , Chronic Disease , Colony Count, Microbial , DNA/metabolism , DNA/ultrastructure , Disease Models, Animal , Haemophilus Infections/microbiology , Haemophilus influenzae/pathogenicity , Humans , Neutrophils/immunology , Neutrophils/metabolism , Otitis Media with Effusion/microbiology
14.
J Parasitol ; 94(1): 169-75, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18372637

ABSTRACT

Microsporidia are obligate intracellular, eukaryotic parasites that are known to infect a variety of invertebrate and vertebrate species and have been reported to include a broad range of host specificities for various cell types. Although it is clear that some species of microsporidia have the ability to disseminate, causing multiorgan infections, it is not understood how dissemination occurs. One hypothesis suggests that mononuclear phagocytes engulf the pathogen and migrate to various organs while the parasite persists and proliferates. This implies that microsporidia have developed methods by which to escape intracellular degradation and can, instead, use the host as a source of nourishment and a vehicle for dissemination. In our study, we investigated the infection kinetics of 2 Encephalitozoon spp. known to cause disseminated disease in humans. Using fluorescence and scanning electron microscopy, it was determined that spore adherence to the host was rapid (3-6 hr), as was the uptake and organization of internal parasitophorous vacuoles (24 hr). Furthermore, replication was shown to occur within macrophages at 72 hr, as measured by the bromodeoxyuridine proliferation assay, and the production of mature spores occurred in host cells at 120 hr. Parasitic replication could be reduced by pretreatment of macrophages with interferon-gamma and bacterial lipopolysaccharide.


Subject(s)
Encephalitozoon/physiology , Macrophages/parasitology , Animals , Cell Adhesion , Cell Line , Cells, Cultured , Encephalitozoon/growth & development , Encephalitozoon/immunology , Host-Parasite Interactions/physiology , Humans , Interferon-gamma/pharmacology , Kinetics , Life Cycle Stages , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Microscopy, Electron, Scanning , Microscopy, Fluorescence , Rabbits , Spores, Protozoan/physiology
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