Identification and Characterization of msf, a Novel Virulence Factor in Haemophilus influenzae.

Haemophilus influenzae is an opportunistic pathogen. The emergence of virulent, non-typeable strains (NTHi) emphasizes the importance of developing new interventional targets. We screened the NTHi supragenome for genes encoding surface-exposed proteins suggestive of immune evasion, identifying a large family containing Sel1-like repeats (SLRs). Clustering identified ten SLR-containing gene subfamilies, each with various numbers of SLRs per gene. Individual strains also had varying numbers of SLR-containing genes from one or more of the subfamilies. Statistical genetic analyses of gene possession among 210 NTHi strains typed as either disease or carriage found a significant association between possession of the SlrVA subfamily (which we have termed, macrophage survival factor, msf) and the disease isolates. The PittII strain contains four chromosomally contiguous msf genes. Deleting all four of these genes (msfA1-4) (KO) resulted in a highly significant decrease in phagocytosis and survival in macrophages; which was fully complemented by a single copy of the msfA1 gene. Using the chinchilla model of otitis media and invasive disease, the KO strain displayed a significant decrease in fitness compared to the WT in co-infections; and in single infections, the KO lost its ability to invade the brain. The singly complemented strain showed only a partial ability to compete with the WT suggesting gene dosage is important in vivo. The transcriptional profiles of the KO and WT in planktonic growth were compared using the NTHi supragenome array, which revealed highly significant changes in the expression of operons involved in virulence and anaerobiosis. These findings demonstrate that the msfA1-4 genes are virulence factors for phagocytosis, persistence, and trafficking to non-mucosal sites.

Panel 4: Recent advances in otitis media in molecular biology, biochemistry, genetics, and animal models.

BACKGROUND: Otitis media (OM) is the most common childhood bacterial infection and also the leading cause of conductive hearing loss in children. Currently, there is an urgent need for developing novel therapeutic agents for treating OM based on full understanding of molecular pathogenesis in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. OBJECTIVE: To provide a state-of-the-art review concerning recent advances in OM in the areas of molecular biology, biochemistry, genetics, and animal model studies and to discuss the future directions of OM studies in these areas. DATA SOURCES AND REVIEW METHODS: A structured search of the current literature (since June 2007). The authors searched PubMed for published literature in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. RESULTS: Over the past 4 years, significant progress has been made in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. These studies brought new insights into our understanding of the molecular and biochemical mechanisms underlying the molecular pathogenesis of OM and helped identify novel therapeutic targets for OM. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: Our understanding of the molecular pathogenesis of OM has been significantly advanced, particularly in the areas of inflammation, innate immunity, mucus overproduction, mucosal hyperplasia, middle ear and inner ear interaction, genetics, genome sequencing, and animal model studies. Although these studies are still in their experimental stages, they help identify new potential therapeutic targets. Future preclinical and clinical studies will help to translate these exciting experimental research findings into clinical applications.

Eradicating chronic ear, nose, and throat infections: a systematically conducted literature review of advances in biofilm treatment.

OBJECTIVE: Bacteria can grow as individual, planktonic organisms or as complex biofilm communities that are more resistant to treatment. This review was designed to systematically search to identify recent laboratory studies on eradication of biofilms in otolaryngologic infections to highlight promising advances in biofilm treatment. DATA SOURCES: A systematic electronic literature search of Medline/PubMed, CINHAL, and Web of Science was conducted for articles describing the treatment of biofilm infections in ear, nose, and throat (ENT) diseases through March 2010. English-language articles and articles with an English abstract that focused on biofilm treatment were considered for review. REVIEW METHODS: Each included article was reviewed by one of the authors for study design, treatment intervention, and outcome. Data from in vitro and animal studies were considered separately from human studies. RESULTS: A total of 30 articles were identified for this review, including 5 studies that included a human treatment component. In general, antibiotics were relatively ineffective for eradicating biofilm infections. Markedly higher antibiotic dosages were required to reduce biofilm presence compared with doses that were effective in eradicating planktonic bacteria. Mupirocin irrigation, gentian violet, and thiamphenicol glycinate acetylcysteine effectively eradicated biofilms. Physical disruption, surfactants, and probiotics were also shown to be beneficial in both nonhuman and human studies. CONCLUSION: Eradicating ENT biofilms is difficult when treating single-organism or mixed flora biofilms. Antibiotic therapy is often ineffective against biofilms, and clinical treatment may need to focus on nonantibiotic therapies that reduce, disrupt, or eradicate ENT biofilms.

Direct demonstration of Staphylococcus biofilm in an external ventricular drain in a patient with a history of recurrent ventriculoperitoneal shunt failure.

External ventricular drains (EVD) are associated with a high infection rate. Early detection of infection is frequently problematic due to a lack of clinical signs and the time period required for culturing. Bacterial biofilms have been suggested to play an important role in the infection of EVD, but direct evidence is as yet lacking. We report the case of a 17- year-old male with Dandy-Walker malformation who presented with headache, nausea and drowsiness; a CT scan revealed enlarged ventricles. The patient had a history of ventriculoperitoneal shunt revision 3 weeks prior to admission. The shunt was removed on suspicion of infection and an EVD placed. Daily surveillance cultures through the EVD were negative and the EVD was replaced on day 5. Examination of the initial EVD by confocal microscopy demonstrated clear intraluminal biofilm formation; molecular analysis by PCR identified Staphylococcus aureus resident on the catheter. To our knowledge, this is the first direct demonstration of an intraluminal biofilm compromising an EVD. Despite the presence of biofilm on this catheter, the patient demonstrated no clinical signs of infection, and the routine surveillance culture was negative. Undetected biofilm may pose a latent risk on EVD and other neurosurgical catheters.

Chaperonin containing T-complex polypeptide subunit eta (CCT-eta) is a specific regulator of fibroblast motility and contractility.

Integumentary wounds in mammalian fetuses heal without scar; this scarless wound healing is intrinsic to fetal tissues and is notable for absence of the contraction seen in postnatal (adult) wounds. The precise molecular signals determining the scarless phenotype remain unclear. We have previously reported that the eta subunit of the chaperonin containing T-complex polypeptide (CCT-eta) is specifically reduced in healing fetal wounds in a rabbit model. In this study, we examine the role of CCT-eta in fibroblast motility and contractility, properties essential to wound healing and scar formation. We demonstrate that CCT-eta (but not CCT-beta) is underexpressed in fetal fibroblasts compared to adult fibroblasts. An in vitro wound healing assay demonstrated that adult fibroblasts showed increased cell migration in response to epidermal growth factor (EGF) and platelet derived growth factor (PDGF) stimulation, whereas fetal fibroblasts were unresponsive. Downregulation of CCT-eta in adult fibroblasts with short inhibitory RNA (siRNA) reduced cellular motility, both basal and growth factor-induced; in contrast, siRNA against CCT-beta had no such effect. Adult fibroblasts were more inherently contractile than fetal fibroblasts by cellular traction force microscopy; this contractility was increased by treatment with EGF and PDGF. CCT-eta siRNA inhibited the PDGF-induction of adult fibroblast contractility, whereas CCT-beta siRNA had no such effect. In each of these instances, the effect of downregulating CCT-eta was to modulate the behavior of adult fibroblasts so as to more closely approximate the characteristics of fetal fibroblasts. We next examined the effect of CCT-eta modulation on alpha-smooth muscle actin (alpha-SMA) expression, a gene product well known to play a critical role in adult wound healing. Fetal fibroblasts were found to constitutively express less alpha-SMA than adult cells. Reduction of CCT-eta with siRNA had minimal effect on cellular beta-actin but markedly decreased alpha-SMA; in contrast, reduction of CCT-beta had minimal effect on either actin isoform. Direct inhibition of alpha-SMA with siRNA reduced both basal and growth factor-induced fibroblast motility. These results indicate that CCT-eta is a specific regulator of fibroblast motility and contractility and may be a key determinant of the scarless wound healing phenotype by means of its specific regulation of alpha-SMA expression.

Cloning and expression of rabbit CCT subunits eta and beta in healing cutaneous wounds.

We have previously identified the CCT subunit eta as specifically reduced in healing fetal skin wounds by differential display, and observed that this reduction is not seen with any other CCT subunit. We now report the cloning and characterization of the cDNAs for rabbit CCT-eta and its closest evolutionary homolog, CCT-beta. Quantitative examination of CCT-eta and ­beta message expression in healing fetal and adult wounds at 12 h post-injury confirms that CCT-eta mRNA is decreased in fetal wound tissues, but actually elevated in adult wound tissues. CCT-beta mRNA, in contrast, remains unchanged in both fetal and adult wound tissues. CCT-eta mRNA remains persistently elevated in healing adult wounds for 28 days following injury, whereas CCT-beta mRNA remains invariant throughout. CCT-eta protein is similarly increased, whereas CCT-beta protein remains unchanged. -smooth muscle actin (-SMA), a recognized substrate of CCT known to be important in integumentary wound healing, was also measured over the course of wound healing, and both mRNA and protein levels were elevated throughout the 28 days.

Expression of receptor for activated C kinase 1 in healing skin and mucosal wounds.

Postnatal (adult) mammalian wound healing results in the formation of scar, whereas fetal mammals are able to effect wound repair without scar. We have investigated the expression pattern of the receptor of activated C kinase 1 (RACK1), a pleiotropic G-protein-like molecule, in healing skin and mucosal wounds in a rabbit model after obtaining a full-length clone of the rabbit RACK1 cDNA. In both adult skin and mucosal wounds, RACK1 mRNA expression is decreased relative to unwounded controls. In contrast, in fetal skin wounds RACK1 expression is unaltered from fetal control. Fibroblasts derived from adult skin tissue express more RACK1 message than fetal skin fibroblasts. These observations suggest that RACK1 may play an important role in distinguishing scarless fetal wound healing from its scirrhous counterpart in adults.

Biofilms in pediatric respiratory and related infections.

Bacteria can grow as free-floating, planktonic bacteria or complex communities called biofilms. Biofilms promote bacterial growth and diversity and offer bacteria unique environments, including aerobic and anaerobic layers, that facilitate resistance to antimicrobial therapies. Respiratory and related structures provide ideal environments for the development of bacterial biofilms, which predispose patients to recurrent and chronic infections. Biofilms are important for the persistence of chronic rhinosinusitis, pulmonary infections in cystic fibrosis, chronic otitis media, and device-related infections. Antimicrobial therapy that is proven effective against planktonic bacteria is often insufficiently effective against the defenses of biofilms. Furthermore, biofilms modify themselves following exposure to antimicrobial therapy, thus developing increased resistance. Understanding the nature of biofilms in common pediatric infections is essential to comprehending the expected course of bacterial illness and identifying treatments that are most likely to be beneficial against more resistant biofilms.

Age of child, more than HPV type, is associated with clinical course in recurrent respiratory papillomatosis.

BACKGROUND: RRP is a devastating disease in which papillomas in the airway cause hoarseness and breathing difficulty. The disease is caused by human papillomavirus (HPV) 6 or 11 and is very variable. Patients undergo multiple surgeries to maintain a patent airway and in order to communicate vocally. Several small studies have been published in which most have noted that HPV 11 is associated with a more aggressive course. METHODOLOGY/PRINCIPAL FINDINGS: Papilloma biopsies were taken from patients undergoing surgical treatment of RRP and were subjected to HPV typing. 118 patients with juvenile-onset RRP with at least 1 year of clinical data and infected with a single HPV type were analyzed. HPV 11 was encountered in 40% of the patients. By our definition, most of the patients in the sample (81%) had run an aggressive course. The odds of a patient with HPV 11 running an aggressive course were 3.9 times higher than that of patients with HPV 6 (Fisher's exact p = 0.017). However, clinical course was more closely associated with age of the patient (at diagnosis and at the time of the current surgery) than with HPV type. Patients with HPV 11 were diagnosed at a younger age (2.4y) than were those with HPV 6 (3.4y) (p = 0.014). Both by multiple linear regression and by multiple logistic regression HPV type was only weakly associated with metrics of disease course when simultaneously accounting for age. CONCLUSIONS/SIGNIFICANCE ABSTRACT: The course of RRP is variable and a quarter of the variability can be accounted for by the age of the patient. HPV 11 is more closely associated with a younger age at diagnosis than it is associated with an aggressive clinical course. These data suggest that there are factors other than HPV type and age of the patient that determine disease course.

Differential expression of chaperonin containing T-complex polypeptide (CCT) subunits during fetal and adult skin wound healing.

Integumentary wound healing in early fetal life is regenerative and proceeds without scar formation. Expressomic analysis of this phenomenon by differential display has previously determined that the eta subunit of the cytosolic chaperonin containing T-complex polypeptide (CCT) is downregulated in the healing fetal wound milieu. We now report that no other CCT subunit shares this distinct pattern of gene regulation as determined by limiting dilution reverse transcriptase polymerase chain reaction (RT-PCR); all seven of the remaining CCT subunits demonstrate no change in messenger RNA (mRNA) expression in healing fetal wounds compared to unwounded control tissue. The alpha subunit, however, did evidence reduced message levels in healing adult wound tissue. We herein report on the cloning and sequence of the complementary DNA (cDNA) for rabbit CCT-alpha and confirm its wound specific decrease in adult tissues through quantitative real-time RT-PCR assay. We also confirm that quantitative evaluation of CCT-alpha and CCT-zeta mRNA expression shows no change in healing fetal wounds.

The role of biofilms in otolaryngologic infections: update 2007.

PURPOSE OF REVIEW: Biofilms have been shown to play a role in otitis media, sinusitis, cholesteatoma, tonsillitis, adenoiditis, and device infections. This article is written to review recent advances in the field. RECENT FINDINGS: The role of biofilms in the persistence of chronic, mucosal-based ENT-related infections was first recognized in otitis media. Definitive proof was lacking until the demonstration of bacterial biofilms on the middle-ear mucosa of children, not only with chronic otitis media with effusion, but also with recurrent otitis media. Strains of Pseudomonas aeruginosa isolated from cholesteatoma are avid biofilm formers. Biofilms have been reported in the adenoids of children with chronic rhinosinusitis, helping to explain the clinical observation that adenoidectomy can be beneficial to children with chronic otitis or chronic rhinosinusiti. Additional studies have confirmed the presence of biofilms in chronic tonsillitis. Biofilms have also been shown to be involved in infected cochlear implants and tracheotomy tubes. SUMMARY: The recognition that chronic otolaryngologic bacterial infections are biofilm related has been the impetus for the development of new technologies for the study of biofilms and their prevention and treatment. Understanding that chronic bacterial infections are biofilm related is fundamental to developing rationale strategies for treatment and prevention.

Unique challenges of obtaining regulatory approval for a multicenter protocol to study the genetics of RRP and suggested remedies.

OBJECTIVE: Investigations that seek to generalize findings or to understand uncommon diseases must be conducted at multiple centers. This study describes the process of obtaining regulatory approval for a minimal risk genetic study in a multi-center setting as undertaken by the Recurrent Respiratory Papillomatosis (RRP) Task Force. STUDY DESIGN AND SETTING: Sequential cohort of American children's hospitals. A single protocol was submitted to each Institutional Review Board (IRB). RESULTS: Documentation was prepared for 14 IRBs over 2.5 years. The median time between enlistment and approval at the first 8 sites was 15 months. Institutions varied considerably in their requirements and in the issues that were raised. Protocols were submitted sequentially and accumulated experience was used in the preparation of applications to subsequent IRBs. Nevertheless, there was no correlation between the accumulated experience and the number of issues that were raised. CONCLUSION: Despite uniform federal standards, all local IRBs required unique and individualized submissions. For multicenter studies, investigators should seriously consider the establishment of cooperative authorization agreements. On a simpler level, a standardized format for applications needs to be adopted nationwide. EBM RATING: B-3b.

Construction and characterization of a highly redundant Pseudomonas aeruginosa genomic library prepared from 12 clinical isolates: application to studies of gene distribution among populations.

OBJECTIVE: To create, array, and characterize a pooled, high-coverage, genomic library composed of multiple biofilm-forming clinical strains of the opportunistic pathogen, Pseudomonas aeruginosa (PA). Twelve strains were obtained from patients with otorrhea, otitis media, and cystic fibrosis as a resource for investigating: difference in the transcriptomes of planktonic and biofilm envirovars; the size of the PA supragenome and determining the number of virulence genes available at the population level; and the distributed genome hypothesis. METHODS: High molecular weight genomic DNAs from 12 clinical PA strains were individually hydrodynamically sheared to produce mean fragment sizes of approximately 1.5 kb. Equimolar amounts of the 12 sheared genomic DNAs were then pooled and used in the construction of a genomic library with approximately 250,000 clones that was arrayed and subjected to quality control analyses. RESULTS: Restriction endonuclease and sequence analyses of 686 clones picked at random from the library demonstrated that >75% of the clones contained inserts larger than 0.5 kb with the desired mean insert size of 1.4 kb. Thus, this library provides better than 4.5x coverage for each of the genomes from the 12 components clinical PA isolates. Our sequencing effort ( approximately 1 million nucleotides to date) reveals that 13% of the clones present in this library are not represented in the genome of the reference P. aeruginosa strain PA01. CONCLUSIONS: Our data suggests that reliance on a single laboratory strain, such as PA01, as being representative of a pathogenic bacterial species will fail to identify many important genes, and that to obtain a complete picture of complex phenomena, including bacterial pathogenesis and the genetics of biofilm development will require characterization of the P. aeruginosa population-based supra-genome.

Direct detection of bacterial biofilms on the middle-ear mucosa of children with chronic otitis media.

CONTEXT: Chronic otitis media (OM) is a common pediatric infectious disease. Previous studies demonstrating that metabolically active bacteria exist in culture-negative pediatric middle-ear effusions and that experimental infection with Haemophilus influenzae in the chinchilla model of otitis media results in the formation of adherent mucosal biofilms suggest that chronic OM may result from a mucosal biofilm infection. OBJECTIVE: To test the hypothesis that chronic OM in humans is biofilm-related. DESIGN, SETTING, AND PATIENTS: Middle-ear mucosa (MEM) biopsy specimens were obtained from 26 children (mean age, 2.5 [range, 0.5-14] years) undergoing tympanostomy tube placement for treatment of otitis media with effusion (OME) and recurrent OM and were analyzed using microbiological culture, polymerase chain reaction (PCR)-based diagnostics, direct microscopic examination, fluorescence in situ hybridization, and immunostaining. Uninfected (control) MEM specimens were obtained from 3 children and 5 adults undergoing cochlear implantation. Patients were enrolled between February 2004 and April 2005 from a single US tertiary referral otolaryngology practice. MAIN OUTCOME MEASURES: Confocal laser scanning microscopic (CLSM) images were obtained from MEM biopsy specimens and were evaluated for biofilm morphology using generic stains and species-specific probes for H influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. Effusions, when present, were evaluated by PCR and culture for evidence of pathogen-specific nucleic acid sequences and bacterial growth, respectively. RESULTS: Of the 26 children undergoing tympanostomy tube placement, 13 (50%) had OME, 20 (77%) had recurrent OM, and 7 (27%) had both diagnoses; 27 of 52 (52%) of the ears had effusions, 24 of 24 effusions were PCR-positive for at least 1 OM pathogen, and 6 (22%) of 27 effusions were culture-positive for any pathogen. Mucosal biofilms were visualized by CLSM on 46 (92%) of 50 MEM specimens from children with OME and recurrent OM using generic and pathogen-specific probes. Biofilms were not observed on 8 control MEM specimens obtained from the patients undergoing cochlear implantation. CONCLUSION: Direct detection of biofilms on MEM biopsy specimens from children with OME and recurrent OM supports the hypothesis that these chronic middle-ear disorders are biofilm-related.

Four mutations in Epidermodysplasia verruciformis 1 (EVER1) gene are not contributors to susceptibility in RRP.

OBJECTIVE: Epidermodysplasia verruciformis is a skin disease characterized by abnormal susceptibility to human papilloma viruses. Recently four mutations in the Epidermodysplasia verruciformis 1 gene (EVER1, also known as TMC6) have been associated with the disease. Because of the phenotypic similarity between Epidermodysplasia verruciformis and recurrent respiratory papillomatosis, we decided to investigate whether any of these mutations accounts for the susceptibility to human papilloma viruses in subjects with recurrent respiratory papillomatosis (RRP). METHODS: Allele-specific PCR and restriction fragment length polymorphisms (RFLPs) were employed for genotyping a cohort of 101 patients with recurrent respiratory papillomatosis. RESULTS: None of these four mutations were found in the studied subjects. CONCLUSION: The absence of these mutations in RRP patients might indicate that EVER 1 alleles are not associated with susceptibility to RRP, or that other, as yet unidentified, mutations in the Epidermodysplasia verruciformis 1 gene, might account for the susceptibility to RRP.

Characterization, distribution, and expression of novel genes among eight clinical isolates of Streptococcus pneumoniae.

Eight low-passage-number Streptococcus pneumoniae clinical isolates, each of a different serotype and a different multilocus sequence type, were obtained from pediatric participants in a pneumococcal vaccine trial. Comparative genomic analyses were performed with these strains and two S. pneumoniae reference strains. Individual genomic libraries were constructed for each of the eight clinical isolates, with an average insert size of approximately 1 kb. A total of 73,728 clones were picked for arraying, providing more than four times genomic coverage per strain. A subset of 4,793 clones were sequenced, for which homology searches revealed that 750 (15.6%) of the sequences were unique with respect to the TIGR4 reference genome and 263 (5.5%) clones were unrelated to any available streptococcal sequence. Hypothetical translations of the open reading frames identified within these novel sequences showed homologies to a variety of proteins, including bacterial virulence factors not previously identified in S. pneumoniae. The distribution and expression patterns of 58 of these novel sequences among the eight clinical isolates were analyzed by PCR- and reverse transcriptase PCR-based analyses, respectively. These unique sequences were nonuniformly distributed among the eight isolates, and transcription of these genes in planktonic cultures was detected in 81% (172/212) of their genic occurrences. All 58 novel sequences were transcribed in one or more of the clinical strains, suggesting that they all correspond to functional genes. Sixty-five percent (38/58) of these sequences were found in 50% or less of the clinical strains, indicating a significant degree of genomic plasticity among natural isolates.

Molecular and imaging techniques for bacterial biofilms in joint arthroplasty infections.

Biofilm formation on surfaces is an ancient and integral strategy for bacterial survival. Billions of years of adaptation provide microbes with the ability to colonize any surface, including those used in orthopaedic surgery. Although remarkable progress has been made in the treatment of orthopaedic diseases with implanted prostheses, infection rates remain between 1% and 2%, and are higher for revision surgeries. The chronic nature of implant infections, their nonresponsiveness to antibiotics, and their frequent culture negativity can be explained by the biofilm paradigm of infectious disease. However, the role of biofilms in orthopaedic implant infections and aseptic loosening is controversial. To address these issues, we developed molecular diagnostic and confocal imaging techniques to identify and characterize biofilms associated with infected implants. We designed PCR and reverse transcription (RT)-PCR-based assays that can be used to detect bacterial infections associated with culture-negative joint effusions that distinguish between physiologically active Staphylococcus aureus and Staphylococcus epidermidis. Using clinical isolates of Pseudomonas aeruginosa, we constructed a series of reporter strains expressing colored fluorescent proteins to observe biofilms growing on 316L stainless steel and titanium orthopaedic screws. Three-dimensional structures of Pseudomonas aeruginosa and staphylococci biofilms growing on the screws were documented using confocal microscopy. The application of these tools for clinical diagnosis and biofilm research in animal and in vitro models is discussed.

Clinical assessment of pediatric obstructive sleep apnea.

OBJECTIVE: To determine whether children with a clinical assessment suggestive of obstructive sleep apnea (OSA) but with negative polysomnography (PSG) have improvement in their clinical assessment score after tonsillectomy and adenoidectomy (T&A) as compared with similar children who do not undergo surgery. METHODS: In a prospective, randomized, investigator-blinded, controlled trial, 59 otherwise healthy children (mean age: 6.3 years [3.0]; 31 boys, 28 girls) with a clinical diagnosis of OSA (clinical assessment score 40) were recruited from the pediatric otolaryngology and pediatric pulmonary private offices and clinics of a tertiary care, academic medical center. A standardized assessment was performed on all patients, including history, physical examination, voice recording, tape recording of breathing during sleep, lateral neck radiograph, echocardiogram, and PSG. A clinical assessment score was assigned. Children with positive PSG (n = 27) were scheduled for T&A, whereas children with negative PSG (n = 29) were randomized to T&A (n = 15) or no surgery (n = 14). Children were reassessed in an identical manner at a planned 6-month follow-up. RESULTS: Follow-up was available for 21 patients with positive PSG, 11 patients with negative PSG randomized to T&A, and 9 nonsurgery patients. In the randomized subjects, the median reduction in clinical assessment score was 49 (range: 32-61) for the T&A patients as compared with 8 (range: -9 to 29) for the nonsurgery patients. Nine (82%) of the T&A patients were asymptomatic (clinical assessment score <20) compared with 2 (22%) of the nonsurgery patients. CONCLUSION: Children with a positive clinical assessment of OSA but negative PSG have significant improvement after T&A as compared with observation alone, thus validating the clinician's role in diagnosing upper airway obstruction.

The role of biofilms in otolaryngologic infections.

PURPOSE OF REVIEW: Bacterial biofilms have recently been shown to be important in diseases of the head and neck. Because the concept of biofilms is novel to most practitioners, it is important to gain a basic understanding of biofilms and to recognize that strategies developed to treat planktonic bacteria are ineffective against bacteria in a biofilm. RECENT FINDINGS: Bacteria preferentially exist in complex, surface-attached organizations known as biofilms. Bacteria in biofilms express a different set of genes than their planktonic counterparts and have markedly different phenotypes. Biofilm bacteria communicate with each other, and have mechanisms to diffuse nutrients and dispose of waste. Biofilms provide bacteria with distinct advantages, including antimicrobial resistance and protection from host defenses. Thus, bacteria exist in a far more complex fashion than previously thought and can best be thought of as "self-assembling multicellular communities." Although a focus on the planktonic form of bacteria has been useful in understanding acute infections, chronic infections are much better understood as biofilm illnesses. Biofilms have been shown to be involved in chronic otitis media, chronic tonsillitis, cholesteatoma, and device-associated infections. SUMMARY: Now that basic research has demonstrated that the vast majority of bacteria exist in biofilms, the biofilm concept of disease is beginning to spread throughout the clinical world. Understanding that many of the infections that affect structures of the head and neck are actually biofilm related is fundamental to developing rational strategies for treatment and prevention.