The nose is the best niche for detection of experimental pneumococcal colonisation in adults of all ages, using nasal wash.

Previous studies have suggested that the pneumococcal niche changes from the nasopharynx to the oral cavity with age. We use an Experimental Human Pneumococcal Challenge model to investigate pneumococcal colonisation in different anatomical niches with age. Healthy adults (n = 112) were intranasally inoculated with Streptococcus pneumoniae serotype 6B (Spn6B) and were categorised as young 18-55 years (n = 57) or older > 55 years (n = 55). Colonisation status (frequency and density) was determined by multiplex qPCR targeting the lytA and cpsA-6A/B genes in both raw and culture-enriched nasal wash and oropharyngeal swab samples collected at 2-, 7- and 14-days post-exposure. For older adults, raw and culture-enriched saliva samples were also assessed. 64% of NW samples and 54% of OPS samples were positive for Spn6B in young adults, compared to 35% of NW samples, 24% of OPS samples and 6% of saliva samples in older adults. Many colonisation events were only detected in culture-enriched samples. Experimental colonisation was detected in 72% of young adults by NW and 63% by OPS. In older adults, this was 51% by NW, 36% by OPS and 9% by saliva. The nose, as assessed by nasal wash, is the best niche for detection of experimental pneumococcal colonisation in both young and older adults.

Evaluation of the upper airway microbiome and immune response with nasal epithelial lining fluid absorption and nasal washes.

Despite being commonly used to collect upper airway epithelial lining fluid, nasal washes are poorly reproducible, not suitable for serial sampling, and limited by a dilution effect. In contrast, nasal filters lack these limitations and are an attractive alternative. To examine whether nasal filters are superior to nasal washes as a sampling method for the characterization of the upper airway microbiome and immune response, we collected paired nasal filters and washes from a group of 40 healthy children and adults. To characterize the upper airway microbiome, we used 16S ribosomal RNA and shotgun metagenomic sequencing. To characterize the immune response, we measured total protein using a BCA assay and 53 immune mediators using multiplex magnetic bead-based assays. We conducted statistical analyses to compare common microbial ecology indices and immune-mediator median fluorescence intensities (MFIs) between sample types. In general, nasal filters were more likely to pass quality control in both children and adults. There were no significant differences in microbiome community richness, α-diversity, or structure between pediatric samples types; however, these were all highly dissimilar between adult sample types. In addition, there were significant differences in the abundance of amplicon sequence variants between sample types in children and adults. In adults, total proteins were significantly higher in nasal filters than nasal washes; consequently, the immune-mediator MFIs were not well detected in nasal washes. Based on better quality control sequencing metrics and higher immunoassay sensitivity, our results suggest that nasal filters are a superior sampling method to characterize the upper airway microbiome and immune response in both children and adults.

Streptococcus pneumoniae colonization in pneumococcal vaccine-naïve human immunodeficiency virus-exposed infected and -uninfected South African children.

Pneumococcal nasopharyngeal colonization is a pre-requisite for pneumococcal disease; the risk for pneumococcal disease is high in children born to women living with human immunodeficiency virus (HIV). We investigated pneumococcal colonization, serotype distribution and antibiotic susceptibility of Streptococcus pneumoniae isolates carried by perinatal HIV-infected and HIV-exposed-uninfected (HEU) children.Serial nasopharyngeal swabs were collected from 331 HIV-infected and 491 HEU children, at up to 6 scheduled timepoints, between median ages of 25 to 181 weeks. Pneumococcus was identified by culture; serotyping and antibiotic susceptibility testing were done by conventional methods. No pneumococcal vaccine was given.HIV-infected children were less likely to be colonized with 7-valent pneumococcal conjugate vaccine 7 serotypes than HEU at a median of 25 weeks of age (23% vs 36%; P < .001); however, no differences in colonization between the 2 groups were observed at subsequent study-visits. Over the 36-months study-period pneumococcal colonization increased in both HIV-infected (from 45% to 77%) and HEU (from 57% to 61%) children. Over the study-period, pneumococcal isolates non-susceptible to cotrimoxazole decreased from 92% to 57% and had a similar trend to penicillin (from 65% to 42%) in HIV-infected children. Similarly, pneumococcal nonsusceptible to cotrimoxazole decreased from 93% to 57% and to penicillin from 69% to 37% in HEU children.Vaccine serotype colonization was common in this population and similar rates were observed in HIV-infected and HEU children. The prevalence of pneumococcal isolates non-susceptible to cotrimoxazole and penicillin decreased with age.

Metagenome - Inferred bacterial replication rates in cystic fibrosis airways.

Bacterial replication rates were determined from metagenome sequencing of nasal lavage, throat swabs and induced sputa collected from healthy subjects and individuals with COPD or cystic fibrosis. More than 90% of peak-to-trough coverage ratios of major clones were above 1.4 indicating that the most abundant bacterial species in the microbial communities were replicating in the airways including common inhabitants such as Prevotella and Streptococcus species as well as the cystic fibrosis pathogens Staphylococcus aureus and Pseudomonas aeruginosa. The populations of P. aeruginosa and S. aureus were replicating their pool of chromosomes more slowly than the populations of the common inhabitants of a healthy airway microbial flora. The assessment of growth dynamics in microbial metagenomes could become a decision-making tool for the diagnosis and management of bacterial infections in cystic fibrosis.

The value of nasopharyngeal aspirate, gastric aspirate and bronchoalveolar lavage fluid in the diagnosis of childhood tuberculosis.

Çakir E, Özdemir A, Daskaya H, Umutoglu T, Yüksel M. The value of nasopharyngeal aspirate, gastric aspirate and bronchoalveolar lavage fluid in the diagnosis of childhood tuberculosis. Turk J Pediatr 2018; 60: 10-13. Pulmonary tuberculosis (TB) is an important cause of morbidity and mortality especially in developing countries. A definitive microbiologic confirmation of Mycobacterium tuberculosis is important in the diagnosis of childhood TB. We aimed to compare the diagnostic value of nasopharyngeal aspirate (NPA), gastric aspirate (GA) and bronchoalveolar lavage (BAL) specimens in children with highly suspected pulmonary tuberculosis (TB). NPA, GA and BAL samples were obtained from forty patients. The mean age was 9.2±4.7 years. Sixty-eight percent of children had a history of household contact and 82% had tuberculin skin test positivity. Acid-fast bacilli (AFB) stain was positive in 22.5% (N=9) of BAL, 17.5% (N=7) of GA, and 10% (N=4) of NPA samples. Positive Lowenstein-Jensen culture was 27.5% (N=11) in BAL, 22.5% (N=9) in GA, and 12.5% (N=5) in NPA samples. Positive AFB stains and growth in TB cultures from BAL fluid and GA samples were both higher than NPA samples (p < 0.006 and p < 0.004, respectively GA). We conclude that NPA specimen fails to determine Mycobacterium tuberculosis in children with highly suspected pulmonary TB when compared to GA or BAL fluid.

The burden of sinus disease in cystic fibrosis lung transplant recipients.

INTRODUCTION: Sinus disease (SD) in cystic fibrosis (CF) is a known risk factor for disease progression, the upper airways (UAW) being a site of primary colonization with Pseudomonas aeruginosa. UAW may function as reservoir for graft colonization after lung transplantation (LuTx), increasing risk of rejection. Aims of this study were to assess the burden of sinus disease in CF LuTx recipients, considering patient-reported symptoms, endoscopically documented signs and microbiological isolates, comparing colonization between upper and lower airways. METHODS: A prospective, observational study was performed on consecutive CF LuTx recipients, recording history, symptoms, and management of SD. Nasal lavage (NL) was evaluated for UAW colonization, with nasal inspection during bronchoscopy and bronchoalveolar lavage (BAL) used to assess lower airways if clinically indicated. RESULTS: Hundred and fifty-four patients were included. Symptoms of SD were reported in 96 (62%) individuals; 87 (56%) had prior sinus surgery. Only 8 (13%) of 60 individuals undergoing bronchoscopy presented completely normal findings of the nasal cavity. Thirty-six (60%) patients presented the same isolates on both NL and BAL. Polyps and mucosal alterations were significantly less frequently seen endoscopically in patients with normal flora in NL microbiology (respectively, 26% vs 70%, P = .003, and 35% vs 68%, P = .013). CONCLUSIONS: Symptoms of SD affected more than 60% of CF LuTx recipients. Nasal endoscopic inspection identified alterations in 55%. The majority of patients presented the same isolates both on NL and BAL performed on the same visit. These results strongly support a role of paranasal sinuses as "reservoir" for descending re-colonization of the lung graft.

Performance of the cobas MRSA/SA Test for Simultaneous Detection of Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus From Nasal Swabs.

OBJECTIVES: Health care-associated methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus (SA) infections are continuing problems. Rapidly determining the MRSA colonization status of a patient facilitates practice to reduce spread of MRSA clinical disease. Sensitive detection of all SA prior to surgery, followed by decolonization, can significantly reduce postoperative infection from this pathogen. Our goal was to validate a new automated assay for this testing. METHODS: We compared performance of the cobas MRSA/SA Test on the cobas 4800 System to direct and enriched chromogenic culture using nasal swabs collected from patients at six United States sites. RESULTS: Compared to direct and enriched culture, the sensitivity for MRSA and SA was 93.1% and 93.9%, and the specificity was 97.5% and 94.2%, respectively. After discrepancy analysis, the sensitivity for MRSA and SA was 97.1% and 98.6%, and the specificity was 98.3% and 95.5%, respectively. Compared to direct culture, sensitivity for detecting any SA was 99.6%. CONCLUSIONS: The cobas MRSA/SA Test is an effective tool to simultaneously perform surveillance testing for nasal colonization of both MRSA and MSSA.

Clinical evaluation of a new single-tube multiplex reverse transcription PCR assay for simultaneous detection of 11 respiratory viruses, Mycoplasma pneumoniae and Chlamydia in hospitalized children with acute respiratory infections.

Respiratory Pathogen 13 Detection Kit (13× kit) is able to simultaneously detect 11 respiratory viruses, Mycoplasma pneumoniae (MP) and Chlamydia in a single reaction. Using 572 Nasopharyngeal aspirates collected from hospitalized children, the clinical performance of 13× kit for detecting 11 respiratory viruses was evaluated in comparison with a routinely used 2-tube multiplex reverse transcription PCR assay (2-tube assay) at provincial Centers for Disease Control and Prevention in China. The clinical performance of 13× kit for detecting MP and Chlamydia was evaluated by commercial real-time quantitative PCR (qPCR) kits or sequencing. For tested viruses, the assay concordance was 95.98% and the kappa coefficient was 0.89. All the MP and Chlamydia positive samples detected by 13× kit were confirmed as true positives. The utilization of the 13× kit in clinical settings will be helpful for doctors to assess clinical outcome according to virus type or multiple infections, and to limit the use of antibiotics.

[Local cytokine therapy of inflammation of the rhinosinusotubal area]. / Mestnaya tsitokinovaya terapiya vospaleniya rinosinusotubarnoi zony.

The objective of the present work was to elaborate a scheme for the effective combined treatment ofinflammation of the rhinosinusotubal area including the local administration of roncoleukin and cyclopheron without antibiotics. The study included 82 patients (27 men and 55 women) at the age from 25 to 55 years presenting with acute inflammation ofroncoleukin and cycloferon. They were divided into two groups. Group 1 was comprised of 39 patients dominated by those with the clinical picture of sinusitis whereas group 2 contained 43 patients in whom symptoms of catarrhal otitis media prevailed. The patients of both groups were treated by the local application of roncoleukin in combination with cycloferon inhalation, intranasal administration of decongestants and mucomodifiers. All the patients underwent, before and after the treatment, the microbiological study of the contents of the sinuses, impedancobarometry, 3D computed tomography, and measurement of the IgA, IgM, IgG, IgE, SIgA, IL-8, TNF-alpha, and albumin levels in the blood sera and lavages. The study has demonstrated the difference between the local cytokine levels in the two groups of the patients. The clinical improvement was documented within 24 hours after the onset of therapy. 93.3% of the patients recovered by day 5. Three (3.7%) of them had to be prescribed antibiotic therapy for the lack of the desired effect of the cytokine treatment. It is concluded that the local application of ronkoleukin and cycloferon in combination with elimination therapy provides a tool for the efficient treatment of the patients suffering frominflammatory pathology of the rhinosinusotubalzone due to its stimulatory action on the immune system at the inflammation site mediated through the activation of the earlier formed targeted immune response, the promotion of the accelerated elimination of the causative factor, and the termination of the pathological process.

Effects of a honeybee lactic acid bacterial microbiome on human nasal symptoms, commensals, and biomarkers.

BACKGROUND: Lactic acid bacteria (LAB) can restore commensal microbiomes and prevent infections. Arguably, nasal administrations of LAB may therefore be beneficial in chronic rhinosinusitis (CRS). Previous studies have examined effects of topical/nasal LAB in children with secretory otitis media, but little is as yet known about their effects on the human nasal airway. The aim of this pilot study was to examine effects on nasal symptoms and commensal bacteria in healthy subjects of nasal administration of a honeybee LAB microbiome; ie, a mixture of 9 Lactobacillus spp. and 4 Bifidobacterium spp. obtained from the honeybee Apis mellifera. Furthermore, we aimed to assess whether or not the honeybee LAB produced a local inflammatory response. METHODS: Twenty-two healthy subjects received a single administration of honeybee LAB in a sham-controlled, double-blinded, and crossover design. Using questionnaires, microbiological methods, and nasal lavages, they were assessed regarding symptoms, changes to commensal bacteria, and inflammatory products in nasal lavage fluids. RESULTS: The honeybee LAB did not produce any symptoms or other untoward effects. No changes were observed of commensal bacteria by the honeybee LAB, and no inflammatory response was detected (compared to sham); ie, unaffected nasal lavage fluid levels of monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), monokine induced by interferon-γ (MIG), interleukin-15 (IL-15), epidermal growth factor (EGF), eotaxin, interferon gamma-induced protein-10 (IP-10), and interleukin-1 receptor antagonist (IL-1RA). CONCLUSION: A single human nasal administration of a honeybee LAB microbiome is well tolerated. Specifically, it does not affect commensal bacteria and does not produce an inflammatory response.

Impact of bacteria in nasal aspirates on disease severity of bronchiolitis.

BACKGROUND: The effect of potentially pathogenic bacteria (PPB) on disease severity in patients with bronchiolitis is understudied. METHODS: This prospective study was carried out in the Children's Hospital of Soochow University during the 2012-2013 autumn and winter seasons. We enrolled consecutive children < 2 years of age hospitalized with an attending physician's diagnosis of bronchiolitis. Nasopharyngeal aspirate samples were tested for multiple respiratory viruses and cultured for Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus. RESULTS: In all, 30% (188 patients) were positive for Strep. pneumoniae, H. influenzae, M. catarrhalis, and Staph. aureus. Length of stay (LOS) for patients with PPB was 4.0 days (interquartile range, IQR, 25th-75th percentile: 3.0-6.0 days) versus 3.0 days (IQR, 3.0-5.0 days) for patients without PPB (p < 0.001). However, requirement and duration of supplemental oxygen were not significantly different between the two groups. H. influenzae was an independent risk factor for hospital LOS ≥ 5.0 days (adjusted odds ratio, 1.75; 95% confidence interval, 1.06-2.91). The presence of PPB was not associated with increased risk of supplemental oxygen requirement. CONCLUSIONS: Our study demonstrated that pediatricians should evaluate for PPB in patients with bronchiolitis, especially when they present with RSV infection, fever or percentage of neutrophils > 40%. The presence of H. influenzae in nasal aspirates is associated with longer LOS in patients with bronchiolitis.

Importance of viruses in acute otitis media.

PURPOSE OF REVIEW: Acute otitis media occurs as a complication of viral upper respiratory tract infection. Bacterial otopathogens and respiratory viruses interact and play important roles in acute otitis media development. A better understanding of viral and bacterial interactions may lead to innovative ways to lessen the burden of this common childhood disease. RECENT FINDINGS: There has been increasing evidence that acute otitis media occurs during upper respiratory infection, even in the absence of nasopharyngeal bacterial colonization. Among the types of viruses associated with acute otitis media, respiratory syncytial virus continues to be the most commonly detected. It is still unclear whether viral load plays an important role in acute otitis media development, but symptomatic upper respiratory tract infection (as opposed to asymptomatic viral infection) is crucial. Widespread use of bacterial and viral vaccines in young children, including pneumococcal conjugate and influenza vaccines, has led to the reduction in otitis media-related healthcare use between 2001 and 2011. There has been no new vaccine against respiratory viruses other than influenza. SUMMARY: Progress has been made toward the reduction of the burden of acute otitis media in the last decade. Success in reducing acute otitis media incidence will rely mainly on prevention of nasopharyngeal otopathogen colonization, as well as reduction in the incidence of viral upper respiratory tract infection.

Respiratory microbiota dynamics following Streptococcus pneumoniae acquisition in young and elderly mice.

The upper respiratory tract (URT) is a distinct microbial niche of low-density bacterial communities and, also, a portal of entry for many potential pathogens, including Streptococcus pneumoniae. Thus far, animal models have been used to study the dynamics of and interactions between limited numbers of different species in the URT. Here, we applied a deep sequencing approach to explore, for the first time, the impact of S. pneumoniae acquisition on URT microbiota in a mouse model, as well as potential age-dependent effects. Young-adult and elderly mice were inoculated intranasally with S. pneumoniae, and nasal lavage samples were collected for up to 28 days postcolonization. Bacterial DNA extracted from lavage samples was subjected to barcoded pyrosequencing of the V5-to-V7 hypervariable region of the small-subunit rRNA gene. We observed highly diverse microbial profiles, with the presence overall of 15 phyla and approximately 645 operational taxonomic units (OTUs). We noted differences in the composition of microbiota between young and elderly mice, with a significantly higher abundance of Bacteroidetes in the young mice. The introduction of S. pneumoniae into the URT led to a temporary dominance of pneumococci in the microbiota of all mice, accompanied by a significant decrease in microbial diversity. As mice gradually cleared the colonization, the diversity returned to baseline levels. Diversification was accompanied by an early expansion of Bacteroidetes, Staphylococcus spp., and Lachnospiraceae. Moreover, the Bacteroidetes expansion was significantly greater in young-adult than in elderly mice. In conclusion, we observed differences in URT microbiota composition between naive young-adult and elderly mice that were associated with differences in pneumococcal clearance over time.

Chronic illness associated with mold and mycotoxins: is naso-sinus fungal biofilm the culprit?

It has recently been demonstrated that patients who develop chronic illness after prior exposure to water damaged buildings (WDB) and mold have the presence of mycotoxins, which can be detected in the urine. We hypothesized that the mold may be harbored internally and continue to release and/or produce mycotoxins which contribute to ongoing chronic illness. The sinuses are the most likely candidate as a site for the internal mold and mycotoxin production. In this paper, we review the literature supporting this concept.

Bacteria in the nose of young adults during wellness and rhinovirus colds: detection by culture and microarray methods in 100 nasal lavage specimens.

BACKGROUND: Patients  with  viral respiratory infections/viral rhinitis/common colds are often treated with antibiotic; however, there is little information on whether or how bacterial microbiota in the nose and nasopharynx might influence the course of viral illnesses. METHODS: To initiate investigation of possible interaction between viral respiratory illness and microbiota of the nose/nasopharynx, we used microarray technology to examine 100 nasal lavage fluid (NLF) samples for bacterial species and recorded the bacterial titer of culturable bacteria. Rhinovirus illnesses were induced by self-inoculation using the "finger to nose or eye natural transmission route" in 10 otherwise healthy young adults. NLF samples were collected during wellness and at specific time points following experimental rhinovirus inoculation. RESULTS: The rhinovirus infection rate was 70%. There were no consistent changes in the prevalence of different bacterial species determined by microarray and bacterial titer by culture methods during rhinovirus infection. The bacterial profile in NLF samples showed high variability between volunteers but low variability in multiple NLFs obtained before and following infection from the same volunteer. Streptococcus epidermidis/coagulase-negative staphylococcus (CNS) were identified in all 10 subjects. One or more bacterial sinus/otitis pathogens were identified by microarray in 6 of the 10 volunteers. The microarray identified a few bacteria not included in traditional bacterial cultures. CONCLUSION: Our pilot study showed that each of the 10 volunteers had a unique bacterial profile in the nose by microarray analysis and that bacterial load did not change during experimental rhinovirus colds. Larger scale studies are warranted.

A prospective study of agents associated with acute respiratory infection among young American Indian children.

BACKGROUND: Native American children have higher rates of morbidity associated with acute respiratory infection than children in the general US population, yet detailed information is lacking regarding their principal clinical presentations and infectious etiologies. METHODS: We pursued a comprehensive molecular survey of bacteria and viruses in nasal wash specimens from children with acute respiratory disease collected prospectively over 1 year (January 1 through December 31, 2009) from 915 Navajo and White Mountain Apache children in their second or third year of life who had been enrolled in an efficacy study of a respiratory syncytial virus monoclonal antibody in the first year of life. RESULTS: During the surveillance period, 1476 episodes of disease were detected in 669 children. Rates of outpatient and inpatient lower respiratory tract illness were 391 and 79 per 1000 child-years, respectively, and were most commonly diagnosed as pneumonia. Potential pathogens were detected in 88% of specimens. Viruses most commonly detected were respiratory syncytial virus and human rhinovirus; the 2009 pandemic influenza A (H1N1) illnesses primarily occurred in the fall. Streptococcus pneumoniae was detected in 60% of subjects; only human rhinovirus was significantly associated with S. pneumoniae carriage. The presence of influenza virus, human rhinovirus or S. pneumoniae was not associated with increased risk for lower respiratory tract involvement or hospitalization. CONCLUSIONS: Acute lower respiratory illnesses occur at disproportionately high rates among young American Indian children and are associated with a range of common pathogens. This study provides critical evidence to support reducing the disproportionate burden of acute respiratory disease among young Native Americans.

Controlled human infection and rechallenge with Streptococcus pneumoniae reveals the protective efficacy of carriage in healthy adults.

RATIONALE: The immunological and protective role of pneumococcal carriage in healthy adults is not known, but high rates of disease and death in the elderly are associated with low carriage prevalence. OBJECTIVES: We employed an experimental human pneumococcal carriage model to investigate the immunizing effect of a single carriage episode. METHODS: Seventy healthy adults were challenged, and of those with carriage, 10 were rechallenged intranasally with live 6B Streptococcus pneumoniae up to 11 months after clearance of the first carriage episode. Serum and nasal wash antibody responses were measured before and after each challenge. MEASUREMENTS AND MAIN RESULTS: A total of 29 subjects were experimentally colonized. No subjects were colonized by experimental rechallenge, demonstrating the protective effect of initial carriage against subsequent infection. Carriage increased both mucosal and serum IgG levels to pneumococcal proteins and polysaccharide, resulting in a fourfold increase in opsonophagocytic activity. Importantly, passive transfer of postcarriage sera from colonized subjects conferred 70% protection against lethal challenge by a heterologous strain in a murine model of invasive pneumococcal pneumonia. These levels were significantly higher than the protection conferred by either precarriage sera (30%) or saline (10%). CONCLUSIONS: Experimental human carriage resulted in mucosal and systemic immunological responses that conferred protection against recolonization and invasive pneumococcal disease. These data suggest that mucosal pneumococcal vaccination strategies may be important for vulnerable patient groups, particularly the elderly, who do not sustain carriage.

PCR detection of Haemophilus influenzae from respiratory specimens.

The detection of Haemophilus influenzae by conventional methods like culture is time-consuming and may give false-negative results, especially during ongoing antibiotic treatment. Therefore, non-culture based methods that are sensitive, specific, and rapid are valuable for early diagnosis and effective therapy. Here we describe a quantitative real-time PCR assay based on the outer membrane P6 gene omp6, to detect H. influenzae and its application on respiratory tract specimens.

Microwave disinfection: assessing the risks of irrigation bottle and fluid contamination.

BACKGROUND: It was previously shown that 50% of irrigation bottles and 40% of irrigation fluids had evidence of bacterial contamination despite cleaning with hot water and soap. Although a novel method of microwave disinfection has recently been proposed to minimize contamination risk, this has not been studied in a real life setting. This study investigates the effectiveness of microwave disinfection for reducing both nasal irrigation bottle and irrigation fluid contamination risk after endoscopic sinus surgery (ESS). METHODS: Twenty consecutive patients underwent ESS for chronic rhinosinusitis. Patients were given NeilMed Sinus Rinse bottles (NeilMed Pharmaceuticals, Inc., Santa Rosa CA) to use twice daily, with microwave cleaning instructions preoperatively. Bottles were collected and cultured 1 week postoperatively. Sterile saline (5 mL) was mixed into the irrigation bottle and cultured separately. An additional 10 patients were recruited whereby the bottle was cultured at collection and immediately after microwave disinfection was performed in the clinic. RESULTS: For the first cohort of the study, 40% of the bottles and 20% of the irrigation samples had positive cultures 1 week postoperatively. Common bacteria included Acinetobacter, coagulase-negative Staphylococcus, and Gram-negative bacilli. For the second cohort of patients, 20% of the irrigation bottles had positive cultures. However, after supervised microwave disinfection, there was a 0% contamination rate. CONCLUSION: Despite detailed instructions on microwave disinfection, positive bacterial cultures may still occur after ESS. This risk, however, appears to be significantly reduced when bottles are microwaved under supervision. These findings suggest either a reduced patient compliance to cleaning or a time-dependent recontamination risk after disinfection.