Nasopharyngeal Infections Research Articles

A sustainable approach for the degradation kinetics study and stability assay of the SARS-CoV-2 oral antiviral drug Molnupiravir

Molnupiravir (MPV) is the first direct-acting oral antiviral drug that effectively decreases nasopharyngeal infections with SARS-CoV-2 virus. The stability of MPV was tested by subjecting the drug to various stress conditions. The drug is liable to oxidative, acidic, and alkaline degradation and showed significant stability against thermal degradation. Mass spectrometry identified the degradation products and guided suggestion of the degradation patterns. Interestingly, while inspecting the UV-absorption spectra, we observed no absorbance at 270 nm for the products of the three degradation pathways (c.f. intact MPV). Direct spectrophotometry seemed a solution that perfectly fit the purpose of the stability assay method in our case. It avoids sophisticated instrumentation and complex mathematical data manipulation. The method determined MPV accurately (100.32% ± 1.62) and selectively (99.49% ± 1.63) within the linear range of 1.50 × 10–5–4.0 × 10–4 M and down to a detection limit of 0.48 × 10–5 M. The proposed method is simple and does not require any preliminary separation or derivatization steps. The procedure proved its validity as per the ICH recommendations. The specificity was assessed in the presence of up to 90% degradation products. The study evaluated the greenness profile of the proposed analytical procedure using the National Environmental Methods Index (NEMI), the Analytical Eco-Scale, and the Green Analytical Procedure Index (GAPI). The three metrics unanimously agreed that the developed procedure results in a greener profile than the reported method. The method investigated the degradation reactions' kinetics and evaluated the reaction order, rate constant, and half-life time for each degradation process.

Low dietary sodium potentially mediates COVID-19 prevention associated with whole-food plant-based diets.

Compared with an omnivorous Western diet, plant-based diets containing mostly fruits, vegetables, grains, legumes, nuts and seeds, with restricted amounts of foods of animal origin, are associated with reduced risk and severity of COVID-19. Additionally, inflammatory immune responses and severe acute respiratory symptoms of COVID-19, including pulmonary oedema, shortness of breath, fever and nasopharyngeal infections, are associated with Na toxicity from excessive dietary Na. High dietary Na is also associated with increased risks of diseases and conditions that are co-morbid with COVID-19, including chronic kidney disease, hypertension, stroke, diabetes and obesity. This article presents evidence that low dietary Na potentially mediates the association of plant-based diets with COVID-19 prevention. Processed meats and poultry injected with sodium chloride contribute considerable amounts of dietary Na in the Western diet, and the avoidance or reduction of these and other processed foods in whole-food plant-based (WFPB) diets could help lower overall dietary Na intake. Moreover, high amounts of K in plant-based diets increase urinary Na excretion, and preagricultural diets high in plant-based foods were estimated to contain much lower ratios of dietary Na to K compared with modern diets. Further research should investigate low Na in WFPB diets for protection against COVID-19 and co-morbid conditions.

Cone-Beam Computed Tomography a Dynamic Tool for Assessment of Canalis Basilaris Medianus a Skull Anomaly – A Retrospective Study

Introduction: Canalis basilaris medianus (CBM) is an anomaly of basiocciput in the clivus at the skull's base, demonstrating six different morphological varieties. CBM can be associated with recurrent meningitis and various other cranial pathologies. It can be seen on maxillary cone-beam computed tomography (CBCT) scan with comparatively less radiation dose than computed tomography (CT). Aim: The aim of this study is to determine a prevalence of CBM on CBCT. Objectives: The objectives of this study are: 1. To identify CBM on CBCT 2. To classify CBM according to their morphological types using CBCT. Methods and Material: This study included 300 maxillary CBCT scans retrieved from archival records from the CBCT diagnostic center, Department of Oral Medicine and Radiology, and the existence of CBM were examined. Scans of both genders with all age groups were selected. The existence of CBM was examined and classified based on its morphological type. Results: Chi-square test was used to carry out the descriptive statistics. The presence of CBM was found in 16 scans with a prevalence rate of 5.33%. Out of 16 scans, 10 (62.5%) were females, and 6 (37.5%) were males. Among them, 13 (81.25%) scans were superior recess variety, and 3 (18.75%) were inferior recess variety; other morphological types were absent. Conclusion: Although the prevalence rate of this anomaly is low, it is clinically significant as it may cause the spread of nasopharyngeal infections to the skull base. The present study revealed that a CBCT scan of the maxillary arch could provide a clear delineation of CBM with comparatively less radiation dose than CT. To the best of our knowledge, the recorded values of the prevalence rate of CBM available in current literature are lower compared to this first-ever study carried out in India.

Endoscopic Nasopharyngectomy Combined With Internal Carotid Artery Pretreatment for Recurrent Nasopharyngeal Carcinoma

Salvage endoscopic nasopharyngectomy (ENPG) is a reasonable choice for resectable recurrent nasopharyngeal carcinoma (rNPC). However, in past decades, complete removal of the tumor was not feasible when the recurrent lesion was adjacent to the internal carotid artery (ICA). The present article introduces innovative strategies to ensure sufficient surgical margins while avoiding accidental injury to the ICA. Retrospective study. Tertiary care center. We retrospectively reviewed rT2-3 rNPC patients with tumor lesions adjacent to the ICA (<5 mm) who underwent ENPG at the Sun Yat-sen University Cancer Center between January 2015 and June 2020. Thirty-seven patients were selected for this study. Seventeen patients underwent ENPG using direct dissection, 10 patients underwent endoscopic-assisted transcervical protection of the parapharyngeal ICA combined with ENPG, and 10 patients underwent ICA embolization followed by ENPG. With a median follow-up duration of 31 months (range, 5 to 53 months), the 2-year overall survival, progression-free survival, locoregional recurrence-free survival, and distant metastasis-free survival rates of salvage ENPG for rNPC adjacent to the ICA were 88.7%, 72.0%, 72.0%, and 97.3%, respectively. The incidences of grade 1-2 and grade 3-5 postoperative complications were 16.2% and 13.5%, respectively. Two patients experienced ICA rupture during direct dissection but were out of danger after vascular embolization therapy. One patient had a positive margin. Two patients had severe nasopharyngeal wound infections with mucosal flap necrosis. ENPG combined with ICA pretreatment allows the feasible and effective resection of rNPC lesions adjacent to the ICA.

Fabrication of feeding plate to an infant with Pierre-Robin syndrome: a case report

Cleft lip and palate is a congenital deformity associated with maxillary sagittal and transverse discrepancies. Feeding is an immediate concern in children born with a cleft as it delays their normal growth. A feeding plate is essential for proper nutrition, and it has a role in craniofacial development and decreases the incidence of otitis media and nasopharyngeal infections. This case report describes a single visit technique for fabrication of feeding prosthesis for a 5- day old new-born infant with cleft lip and palate. The prosthesis helps in reducing the flow of food into the nasopharynx, thus decreasing the incidence of Otis media and oro-nasopharyngeal infections.

An Investigation into the Biochemical, Hematological, and Histopathological effects of Glyphaea brevis Extracts in Albino rats: Toxicological Appraisal

Introduction: Drugs from the plants are easily available, less expensive, safe, and efficient and rarely have side effects. Glyphaea brevis leaf decoction is reported to be the potent treatment of sexually transmitted infections, abortifacient, ecbolic, and antiemetic, in eye treatment, liver problems and nasopharyngeal infections. Methods: The aqueous, ethanolic and methanolic extracts of Glyphaea brevis sample were administered to the rats orally once daily at a dose of 250, 500 and 750 mg/kg, body weight for 30 days (on short-term effect) and 60 days (long-term effect). The hematological, biochemical parameters and histopathological examination were studied in the rats. Results: There was a significant difference within the hematological profile of the studied rats for all doses of the methanolic extracts of G. brevis (p < 0.05). The oxygen-carrying capacity of the blood and amount of oxygen delivered to the tissues of the rats had increased following extract administration. Alanine minotransferase (ALT), Aspartate aminotransferase (AST) and Alkaline phosphatase (ALP) levels of the albino rats at all dosage administered were statistically significant compared to the control. Histopathological examination showed kupffer cell activation in the liver, normal histology of the kidney and tubules, no signs of glomeronephritis, and mild coronary vascular congestion of the heart. Conclusion: It is proposed that G. brevis plant extract has a function of raising White blood cells WBC levels within a normal range such that it can efficiently and effectively fight infections. Treatment with the extracts suggested no impairment of normal kidney functions, thus could be considered as a natural product in the management of diseases.

Chronic adenoiditis.

In addition to acute adenoiditis and adenoid hypertrophy/vegetation, chronic adenoiditis is another disease of the adenoids. However, most physicians overlook chronic adenoiditis or confuse it with adenoid hypertrophy/vegetation. The incidence of chronic adenoiditis has increased in recent years as a result of higher rates of chronic nasopharyngeal or upper airway infections. The clinical characteristics of chronic adenoiditis can include but are not restricted to the following: long-term infection (especially bacterial infection); obstruction of the upper airway; infections of adjacent regions, such as the nose, nasal sinus, pharyngeal space, middle ear, and atlantoaxial joint; induced upper airway cough syndrome; and the presence of several “infectious-immune” diseases, including rheumatic fever, autoimmune nephropathy, and anaphylactoid purpura. To date, no consensus on the treatment of chronic adenoiditis is available. However, adenoidectomy can address the local obstruction, and some patients benefit from systemic or local anti-bacterial therapy. Physicians in the Departments of Otolaryngology, Respiration, and Pediatrics should be familiar with the clinical manifestations of chronic adenoiditis and try to develop effective treatment methods for this disease.

Management of Chronic Urticaria

The management of urticaria, although complex, relies on two postulates: • Recognition and eradication of the triggering factor(s) • Provision of symptomatic relief Recognition and eradication of the triggering factors(s) Factors known are drugs, food, infections, and physical stimuli. Drugs: Analgesics and NSAIDs can exacerbate already present urticaria and are also recognized triggers of new-onset urticaria.2 When suspected, they should be withdrawn entirely or can be replaced. ACE inhibitors can cause angioedema. Eradication of infectious agents Infections and infestations should be treated where suspected, including infections of the GI tract e.g., H Pylori associated gastritis3, nasopharyngeal bacterial infections, and intestinal worms.8 Management of diet The allergens in food need to be avoided if a patient has type I hypersensitivity to any one of these allergens. Pseudo-allergic reactions5 which are not IgE mediated have been described for organic foods and food additives.9-13 Physical stimuli They are usually recognized and controlled, e.g., in chronic pressure urticaria patients are advised to use bags with a wide handle and similarly, in symptomatic dermographism, simple avoidance of friction can give relief from symptoms.15 Symptomatic therapy One of the objectives of symptomatic therapy is to mask the effects of histamine, platelet-activating factor, and other mast cell mediators. Histamine plays a primary role in inducing the symptoms associated with urticaria. The activation of receptors on endothelial cells by histamine results in wheals whereas this histamine receptor activation on sensory nerves results in itching. Different guidelines have been proposed for managing chronic urticaria including the EACCI [5] and BSACI [4].

Clinical Spectrum, Diagnosis and Outcome of Rare Fungal Infections in Patients with Hematological Malignancies: Experience of 15-Year Period from a Single Tertiary Medical Center.

Patients with hematological malignancies and allogeneic hematopoietic stem-cell transplant recipients carry a high risk of rare (non-Aspergillusmolds and non-Candida yeasts) invasive fungal infections (IFI). We retrospectively evaluated and described the patient profile, clinical manifestations, isolated species, treatment and outcome of patients with hematological malignancies diagnosed with these rare IFIs during 15years in a large single hemato-oncology center. Eighty-seven patients with hematological malignancies treated in our center had at least one positive culture or molecular identification of a rare fungus. Ninety-three isolates were considered the etiological agents of the infection. The most common underlying hematological malignancy was acute myeloid leukemia, 36 patients (41.4%). Eighty patients (91%) received chemotherapy less than 30days prior to IFI diagnosis. The most frequent site of infection was the respiratory tract: 34 patients (39%) had pulmonary and 19 patients (22%) had a sinusal or nasopharyngeal infections. Disseminated infection, defined as positive blood cultures or parallel infection in multiple organ systems, was documented in 20 patients (23%). The most common fungal species were Fusarium (35%) and Zygomycetes (25%). Coinfection with more than one fungus was noted in 20 patients (23%). Forty-seven of 87 patients (54%) in this study died within 90days of IFI diagnosis. Rare IFIs in patients with hematological malignancy become increasingly frequent. Early identification with traditional and molecular methods is important in management of these patients.

DOP57 Vedolizumab has similar efficacy rates in young and elderly patients: A binational, multicentre, retrospective case–control study

Abstract Background Treatment of inflammatory bowel diseases (IBD) is associated with multiple side effects, such as malignancies and infections, that may be more common in the elderly population. The aim of this study was to compare the safety and efficacy of vedolizumab (VDZ) in young and elderly patients. Methods This is a binational, multicentre, retrospective, case–control study consisting of patients from multiple centres in Israel and from Edinburgh, UK. IBD patients in whom VDZ treatment was initiated during 2015–2019, and were followed for at least 14 weeks, were included in the study according to their age groups: ≤40 years or ≥60 years. Patients were matched for disease duration, classification and severity. Results We recruited 144 patients (82 CD and 62 UC) to the elderly cohort and 140 patients (83 CD and 57 UC) to the young cohort. The respective average age was 70.2 ± 7.3 years and 29.6 ± 5.7 years. Elderly patients had significantly more cardiovascular, metabolic and respiratory co-morbidities and had less prior exposure to anti-TNF agents compared with the young cohort (CD: 51% vs. 88%, p &amp;lt; 0.001; UC: 47% vs. 70%, p = 0.03). Clinical and endoscopic responses were comparable between the groups at Weeks 14 and 52 among elderly and young (Week 52 remission: CD: 40% vs. 35%, p = 0.7; UC: 48% vs. 51%, p = 0.84) (Figure 1). However, the use of more than one anti-TNF agent was an independent predictor of poor response and remission rates to VDZ at all time points among the elderly (OR 0.13; 95% CI 0.03–0.69). A total of 49 adverse events were documented, 23 (16%) in the young cohort and 26 (18%) in the elderly cohort (p = 0.5). Overall there were significantly more infections in the elderly cohort (3 (2%) vs. 17 (12%), p = 0.002) and included nasopharyngeal, urinary, skin and Clostridium difficile infections. None of them was fatal but one patient stopped treatment due to urinary sepsis. There were significantly more non-specific adverse events such as headache and myalgia in the young cohort (8% vs. 2%, p = 0.03). Six patients (4%) in the young cohort required drug discontinuation due to adverse events compared with 4 patients (3%) in the elderly cohort (p = 0.5). The reasons for discontinuation were similar between the groups. Conclusion VDZ is equally effective in elderly and young IBD patients. This study shows an increased risk of overall infections in the elderly cohort, it is unclear whether these are related to VDZ treatment or the age and background diseases of these patients. In elderly patients, the use of VDZ before anti-TNF therapy may improve response and remission rates.

Environmental factors and a risk for multiple sclerosis in the Altai Territory

Multiple sclerosis (MS) is a chronic dysimmune neurodegenerative disease of the central nervous system, the risk of which depends on genetic and environmental factors. The Altai Territory of the Russian Federation shows an increase in the prevalence of MS from 15.5 cases per 100,000population in 1984 to 56.1 in 2017.Objective: to identify potential environmental risk factors for MS in the Altai Territory.Patients and methods. A one-stage randomized study using the method of analytical epidemiology covered 200patients with MS and 200 volunteers without this condition, the representatives of European ethnicity, who were born and lived in the Altai Territory. The investigators surveyed the patients, analyzed their medical records, and assessed the relationship of the prevalence of MS to the characteristics of the territories of residence.Results and discussion. The prevalence of MS was 1.8 times higher in cities and towns than in villages (p=0.003), in areas with heavy metal (lead and molybdenum) ore deposits, chemical and oil refineries located within a 5-km radius from the place of residence. The risk of MS is unassociated with measles, rubella, chicken pox, mumps, whooping cough, herpes infection, chronic nasopharyngeal bacterial infections, diabetes mellitus, allergic status, and contact with household, agricultural, metal, and medicinal poisons, organic solvents, and oil products.Conclusion.The identified environmental risk factors can serve as a basis for recommendations for the prevention of MS in persons at high genetic risk for this disease.

Comparative characteristics of the effect made by natural and synthetic antiseptics on microorganisms causing bacterial nasopharyngeal infections

Local antimicrobial therapy of nasopharyngeal infections takes an important role in reducing microbial colonization, contributes to the reduction of inflammation and accelerates patient`s recovery. The purpose of our work was to compare the effect of natural and synthetic antiseptics on clinical strains of microorganisms (S.aureus, S.pyogenes, K.pneumoniae, K.rhinoscleromatis), which caused infections of the upper respiratory tract. The antimicrobial action of the antiseptics (sanguiritrinum, chlorophyllipte, decasan, miramistin) was studied on 26 clinical strains. For comparative antimicrobial asssay, the double dilution test was used; the antiseptic activity index (AAI) was counted; a quantitative suspension test was performed in order to estimate decontaminating ability of studied antiseptics. The bactericidal action of decasan and myramistin on clinical strains of S.aureus and S.pyogenes did not exceed 8 μg / ml, the same activity of sanguviritrin was observed at 16–26 μg / ml, and chlorophyllitine at 55–94 μg / ml, respectively. Klebsiella had high sensitivity to decasan, sanguiritrinum, myramistin (MCC from 2.5 to 20 μg / ml). High AAIs of all antiseptics was revealed for S.aureus (from 8.5 for chlorophyllipte and 78.1 for decasan). The 0.2% solution of sanguiritrinum had the highest resource of effective action according to AAI data. Synthetic antiseptics had a complete decontaminating effect on most strains after exposure for 5 minutes. Natural antiseptics demonstrated low decontaminating ability, even after exposure for 60 minutes. As a result of a comparative study of solutions containing natural and synthetic antiseptics, the benefits of the latter to microorganisms, which most often caused infections of upper respiratory infections, were established.

Azithromycin to prevent post-discharge morbidity and mortality in Kenyan children: a protocol for a randomised, double-blind, placebo-controlled trial (the Toto Bora trial)

IntroductionChild mortality due to infectious diseases remains unacceptably high in much of sub-Saharan Africa. Children who are hospitalised represent an accessible population at particularly high risk of death, both during...

Modeling specific antibody responses to natural immunization to predict a correlate of protection against infection before commencing a clinical vaccine trial

ABSTRACT Background Clinical trials of vaccines for children to prevent acute otitis media (AOM) infections caused by the bacteria Streptococcus pneumonia (Spn) are in Phase I. The objective of this study was to use serum antibody measurements to pneumococcal purified protein candidate antigens that occurred after natural “immunization” to predict a correlate of protection response needed following an injectable vaccine against AOM in children. Methods 590 nasal and serum samples were collected from 129 healthy children at 6, 9, 12, 15, 18, 24 and 30–36 months of age and when the child developed AOM. Middle ear fluid to detect Spn was collected at every episode of AOM. Quantitative ELISA was used to determine serum IgG against 7 Spn vaccine antigens: PspA clade 3, PspA clade 5, PhtD, PhtE, LytB, PcpA and Ply. A correlate of protection (COP) was estimated by regressing AOM events against age adjusted antibody levels induced by nasopharyngeal colonization and AOM infections, using logistic regression and generalized estimating equation methods. Results A significant COP was found for Spn PhtD (p = 0.0015), PhtE (p = 0.00034), LytB (p = 0.004), PcpA (p = 0.002), and Ply (p = 0.007) between higher antibody levels and reduced frequency of AOM. We estimated that a 2-fold higher antibody level in a child than the mean antibody level induced by NP colonization (after adjusting for subject age) to PhtD, LytB, PcpA, PhtE or Ply reduced the risk of AOM by 14–21%, a 4-fold higher level reduced it by 25–38% and a 10-fold higher level reduced it by 39–54%. Conclusion We developed a model to predict the necessary level of serum antibody and fold higher above a threshold to PhtD, PhtE, LytB, PcpA and Ply that would correlate with a reduced likelihood of AOM in children age 6–24 months old if enrolled in a Phase III clinical efficacy trial.

Tafenoquine for malaria prophylaxis in adults: An integrated safety analysis.

Tafenoquine is a new prophylactic antimalarial drug. The current analysis presents an integrated safety assessment of the Tafenoquine Anticipated Clinical Regimen (Tafenoquine ACR) from 5 clinical trials, including 1 conducted in deployed military personnel and 4 in non-deployed residents, which also incorporated placebo and mefloquine comparator groups. Adverse events (AEs) were coded according to the Medical Dictionary for Regulatory Activities (MedDRA®, Version 15.0) and summarized. Among all subjects who had received the Tafenoquine ACR, safety findings were compared for subjects who were deployed military personnel from the Australian Defence Force (Deployed ADF) versus non-deployed residents (Resident Non-ADF). The incidence of at least one AE was 80.6%, 64.1%, 67.6% and 94.9% in the mefloquine, placebo, tafenoquine Resident Non-ADF and tafenoquine Deployed ADF groups, respectively. The latter group had a higher incidence of AEs related to military deployment. AEs that occurred at ≥ 1% incidence in both tafenoquine sub-groups and at a higher frequency than placebo included diarrhea, nausea, vomiting, gastroenteritis, nasopharyngeal tract infections, and back/neck pain. Weekly administration of tafenoquine for up to six months increased the incidence of gastrointestinal AEs, certain infections, and back/neck pain, but not the overall incidence of AEs versus placebo. CLINICAL TRIAL REGISTRATION NUMBERS/CLINICALTRIALS. NCT02491606; NCT02488980; NCT02488902.

Modeling Specific Antibody Responses to Natural Immunization to Predict a Correlate of Protection Against Infection Before Commencing a Clinical Vaccine Trial

ABSTRACTBackground: Clinical trials of vaccines for children to prevent acute otitis media (AOM) infections caused by the bacteria Streptococcus pneumonia (Spn) are in Phase I. The objective of this study was to use serum antibody measurements to pneumococcal purified protein candidate antigens that occurred after natural “immunization” to predict a correlate of protection response needed following an injectable vaccine against AOM in children.Methods: 590 nasal and serum samples were collected from 129 healthy children at 6, 9, 12, 15, 18, 24 and 30–36 months of age and when the child developed AOM. Middle ear fluid to detect Spn was collected at every episode of AOM. Quantitative ELISA was used to determine serum IgG against 7 Spn vaccine antigens: PspA clade 3, PspA clade 5, PhtD, PhtE, LytB, PcpA and Ply. A correlate of protection (COP) was estimated by regressing AOM events against age adjusted antibody levels induced by nasopharyngeal colonization and AOM infections, using logistic regression and ge...

Clival Osteomyelitis with Retropharyngeal and Epidural Abscesses in a Child

Purpose: Osteomyelitis of the clivus is a rare, life threatening infection in children and can develop from adjacent sinonasal and temporal bone infection. It has been postulated that patients with congenital anomalies of the clivus including fossa navicularis may be at increased risk for extension of nasopharyngeal infections into the clivus. This is the first report describing association with both intracranial and retropharyngeal collections.

Quantifying the Two P6 Populations in Various Strains of Nontypable Haemophilus influenzae

Nontypeable Haemophilus influenzae (NTHi) is a pathogenic bacterium that causes acute otitis media (ear infections) and nasopharyngeal infections. There is a commonly used vaccine against the type B form of Hi (Hib), but there is no vaccine to protect against NTHi in the United States. The lipoprotein P6 found on the outer membrane (OM) of NTHi is currently one of the leading protein vaccine candidates for protection against NTHi. However, research from our lab has shown that P6 can be inserted into the OM in two different orientations: attached to the inner leaflet of the OM and facing in toward the periplasm or attached to the outer leaflet of the OM and facing out toward the extracellular space. When P6 is in its external orientation, it can interact with antibodies, making it a suitable target for vaccines. In this study, we used a biotinylation labeling technique and immunoblotting to separate and quantify the external (surface exposed) P6 and internal P6. The results of our study suggest that in the clinical strains of NTHi that we tested, only a minor population of P6 is surface exposed. We consider the possible ramifications of minimal surface exposure on P6′s vaccine candidacy.

Virulence Plasmids of Nonsporulating Gram-Positive Pathogens.

Gram-positive bacteria are leading causes of many types of human infection, including pneumonia, skin and nasopharyngeal infections, as well as urinary tract and surgical wound infections among hospitalized patients. These infections have become particularly problematic because many of the species causing them have become highly resistant to antibiotics. The role of mobile genetic elements, such as plasmids, in the dissemination of antibiotic resistance among Gram-positive bacteria has been well studied; less well understood is the role of mobile elements in the evolution and spread of virulence traits among these pathogens. While these organisms are leading agents of infection, they are also prominent members of the human commensal ecology. It appears that these bacteria are able to take advantage of the intimate association between host and commensal, via virulence traits that exacerbate infection and cause disease. However, evolution into an obligate pathogen has not occurred, presumably because it would lead to rejection of pathogenic organisms from the host ecology. Instead, in organisms that exist as both commensal and pathogen, selection has favored the development of mechanisms for variability. As a result, many virulence traits are localized on mobile genetic elements, such as virulence plasmids and pathogenicity islands. Virulence traits may occur within a minority of isolates of a given species, but these minority populations have nonetheless emerged as a leading problem in infectious disease. This chapter reviews virulence plasmids in nonsporulating Gram-positive bacteria, and examines their contribution to disease pathogenesis.

872 Antimicrobial Resistance of Streptococcus Pneumoniae Isolated From Children with Nasopharyngeal Carriage and Infections During the 9-Year Period (1999-2007)

Aim: Streptococcus pneumoniae continues to be an important cause of community-acquired respiratory tract infections. Because of increase in its antimicrobial resistance, the surveillance of the local antimicrobial susceptibility of S.pneumoniae should be carried out regularly.Methods: Streptococcus pneumoniae strains were isolated from children on admission to The Children's Memorial Health Institute, Warsaw, Poland between Jan 1999 and Dec 2007. A total of 784 isolates of S.pneumoniae were collected. Susceptibility to antibiotics was analyzed in two periods: 1999-2002 and 2003-2007. All the strains (185) collected in the first period originated from children with pneumococcal diseases. Of the 599 strains obtained in the second period, 234 were isolated from children with S.pneumoniae infection and 365 from children with nasopharyngeal carriage.Results and Conclusions: Rate of resistance to penicillin was stable during the whole period of the study (3% vs. 4%). Higher resistance rates to erythromycin (19% vs. 29%), clindamycin (14% vs. 26%) and lower resistance rates to tetracycline (37% vs. 9%) and co-trimoxazole (47% vs. 41%) were observed among isolates obtained in the second period. S.pneumoniae strains isolated from infections and from carriage exhibited similar resistance patterns.