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The PECACE domain: a new family of enzymes with potential peptidoglycan cleavage activity in Gram-positive bacteria
Estelle Pagliero, Otto Dideberg, Thierry Vernet, Anne Di Guilmi
BMC Genomics , 2005, DOI: 10.1186/1471-2164-6-19
Abstract: Homology searches of the pneumococcal genome allowed the identification of a new domain putatively involved in peptidoglycan cleavage (PECACE, PEptidoglycan CArbohydrate Cleavage Enzyme). This sequence has been found exclusively in Gram-positive bacteria and gene clusters containing pecace are conserved among Streptococcal species. The PECACE domain is, in some instances, found in association with other domains known to catalyze peptidoglycan hydrolysis.A new domain, PECACE, putatively involved in peptidoglycan hydrolysis has been identified in S. pneumoniae. The probable enzymatic activity deduced from the detailed analysis of the amino acid sequence suggests that the PECACE domain may proceed through a LT-type or goose lyzosyme-type cleavage mechanism. The PECACE function may differ largely from the other hydrolases already identified in the pneumococcus: LytA, LytB, LytC, CBPD and PcsB. The multimodular architecture of proteins containing the PECACE domain is another example of the many activities harbored by peptidoglycan hydrolases, which is probably required for the regulation of peptidoglycan metabolism. The release of new bacterial genomes sequences will probably add new members to the five groups identified so far in this work, and new groups could also emerge. Conversely, the functional characterization of the unknown domains mentioned in this work can now become easier, since bacterial peptidoglycan is proposed to be the substrate.The bacterial cell wall resists intracellular pressure and gives the bacterium its particular shape. Cell wall reinforcement is brought about by a strong scaffolding structure, the peptidoglycan, which is formed by glycan strands and peptide chains held together by covalent bonds, resulting in a mono- or multilayered network. The glycan strands are composed of N-acetylglucosamine (GlcNAc) and N-acetylmuramyl (MurNAc) residues linked together by β-1,4 glycosidic bonds. Peptides are covalently attached to the lactyl group of the m
Pneumococcal Nasopharyngeal Colonization During the First Days of Antibiotic Treatment in Pediatric Patients
Q Khotayi,MT Ashtiani,N Makki,D Shekarabi
Iranian Journal of Pediatrics , 2002,
Abstract: This prospective study was conducted to observe changes in nasopharyngeal (NP) pneumococcal carriage within 4 to 5 days after initiation of commonly used antibiotics for 150 patients who were admitted at infectious disease unit of children’s medical center in Tehran to determine whether a significant increase in the carriage rate of drug (Penicillin) resistant S.pneumonia on NP can be observed within this short interval. Nasopharyngeal culture for S.pneumonia was obtained before (Day 1) and after (Day 4 to 5) initiation of antibiotic treatment. Antibiogram was performed in all isolates and the MIC of penicillin in 20 resistant S.pneumonia. By E-test method among the initial 46 (30%) pneumococcal isolates 28 (60%) were sensitive and 8 (17%) were resistant to penicillin. After 4 to 5 days of antibiotic treatment with various drugs, 20 (13%) pneumococcal isolates in the culture were obtained, of whom 12 patients (60%) were resistant to penicillin and 8 patients (40%) were sensitive. In 4 of 150 patients (2.6%) a new S.pneumonia isolate was recovered 4 to 5 days after initiation of treatment. All of those isolates were penicillin-resistance. Conclusion: A rapid detection of penicillin-nonsusceptible NP pneumococcal isolates during antibiotic treatment is common. This may contribute to the spread of resistant pneumococci.
Nasopharyngeal Bacterial Colonization and Gene Polymorphisms of Mannose-Binding Lectin and Toll-Like Receptors 2 and 4 in Infants  [PDF]
Juho Vuononvirta, Laura Toivonen, Kirsi Gr?ndahl-Yli-Hannuksela, Alex-Mikael Barkoff, Laura Lindholm, Jussi Mertsola, Ville Peltola, Qiushui He
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026198
Abstract: Background Human nasopharynx is often colonized by potentially pathogenic bacteria. Gene polymorphisms in mannose-binding lectin (MBL), toll-like receptor (TLR) 2 and TLR4 have been reported. The present study aimed to investigate possible association between nasopharyngeal bacterial colonization and gene polymorphisms of MBL, TLR2 and TLR4 in healthy infants. Methodology/Principal Findings From August 2008 to June 2010, 489 nasopharyngeal swabs and 412 blood samples were taken from 3-month-old healthy Finnish infants. Semi-quantitative culture was performed and pyrosequencing was used for detection of polymorphisms in MBL structural gene at codons 52, 54, and 57, TLR2 Arg753Gln and TLR4 Asp299Gly. Fifty-nine percent of subjects were culture positive for at least one of the four species: 11% for Streptococcus pneumoniae, 23% for Moraxella catarrhalis, 1% for Haemophilus influenzae and 25% for Staphylococcus aureus. Thirty-two percent of subjects had variant types in MBL, 5% had polymorphism of TLR2, and 18% had polymorphism of TLR4. Colonization rates of S. pneumoniae and S. aureus were significantly higher in infants with variant types of MBL than those with wild type (p = .011 and p = .024). Colonization rates of S. aureus and M. catarrhalis were significantly higher in infants with polymorphisms of TLR2 and of TLR4 than those without (p = .027 and p = .002). Conclusions Our study suggests that there is an association between nasopharyngeal bacterial colonization and genetic variation of MBL, TLR2 and TLR4 in young infants. This finding supports a role for these genetic variations in susceptibility of children to respiratory infections.
Nasopharyngeal colonization and penicillin resistance among pneumococcal strains: a Worldwide 2004 update
Cardozo, Déa M.;Nascimento-Carvalho, Cristiana M. C.;Souza, Fabiane R.;Silva, Nívea M. S.;
Brazilian Journal of Infectious Diseases , 2006, DOI: 10.1590/S1413-86702006000400015
Abstract: surveillance of nasopharyngeal pneumococcus has proven to be a valuable tool for the monitoring of antibiotic resistance. we reviewed the latest information on colonization rate and penicillin resistance by making a medline search, using the terms "nasopharyngeal carriage" and "streptococcus pneumoniae". out of 225 articles found, data from 109 recent publications (89% from 1996-2003) were analyzed. data were reported from 41 countries of six continents. individuals under the age of five (64.3%) or 10 years (85.7%) were enrolled, including children attending day-care centers (32.1%) or orphanages (3.6%), and healthy individuals (78.6%) or sick patients (43.6%); biological samples were collected mainly by nasopharyngeal swabs (89.3%). the highest colonization rates were reported from africa (85-87.2%), where several authors did not find high rates of penicillin resistance. on the other hand, studies conducted in north and central america reported high-level penicillin resistance at rates of approximately 20-30%. great variation in the rates of pneumococcal colonization and penicillin resistance were observed within regions or continents. there were also considerable differences in similar populations located in different areas of the same country. data regarding pneumococcal colonization and penicillin resistance are not available from most countries. we also examined the use of antibiotics to treat pneumococcal infections.
Streptococcus pneumoniae nasopharyngeal colonization induces type I interferons and interferon-induced gene expression
Elizabeth A Joyce, Stephen J Popper, Stanley Falkow
BMC Genomics , 2009, DOI: 10.1186/1471-2164-10-404
Abstract: Colonization with S. pneumoniae altered the expression of hundreds of genes over the course of the study, demonstrating that carriage is a dynamic process characterized by increased expression of a set of early inflammatory responses, including induction of a Type I Interferon response, and the production of several antimicrobial factors. Subsequent to this initial inflammatory response, we observed increases in transcripts associated with T cell development and activation, as well as wounding, basement membrane remodeling, and cell proliferation. Our analysis suggests that microbial colonization induced expression of genes encoding components critical for controlling JAK/STAT signaling, including stat1, stat2, socs3, and mapk1, as well as induction of several Type I Interferon-inducible genes and other antimicrobial factors at the earliest stages of colonization.Examining multiple time points over six weeks of colonization demonstrated that asymptomatic carriage stimulates a dynamic host response characterized by temporal waves with distinct biological programs. Our data suggest that the usual response to the presence of the pneumocccus is an initial controlled inflammatory response followed by activation of host physiological processes such as response to wounding, basement membrane remodeling, and increasing cellular numbers that ultimately allow the host to maintain an intact epithelium and eventually mount a preventive adaptive immune response.Streptococcus pneumoniae, also known as the pneumococcus, is a Gram positive, encapsulated bacterium recognized as an important cause of pneumonia, meningitis and sepsis throughout the world. Despite its nefarious reputation, this organism usually establishes an obligate asymptomatic association within the human nasopharyngeal cavity. This carrier state is of critical importance since individuals asymptomatically colonized with S. pneumoniae serve as a reservoir for person to person transmission of this organism, highligh
Nasopharyngeal colonization with methicillin-resistant staphylococcus aureus and mortality among patients in an intensive care unit
Fortaleza, Cristiane Ravagnani;Melo, Edson Carvalho de;Fortaleza, Carlos Magno Castelo Branco;
Revista Latino-Americana de Enfermagem , 2009, DOI: 10.1590/S0104-11692009000500013
Abstract: nasopharyngeal colonization with methicillin-resistant staphylococcus aureus (mrsa) is common in critically ill patients, but its effect on patient prognosis is not fully elucidated. a retrospective cohort study was carried out enrolling 122 patients from an intensive care unit who were screened weekly for nasopharyngeal colonization with mrsa. the outcomes of interest were: general mortality and mortality by infection. several exposure variables (severity of illness, procedures, intercurrences and mrsa nasopharyngeal colonization) were analyzed through univariate and multivariable models. factors significantly associated with mortality in general or due to infection were: apache ii and lung disease. the performance of surgery predicted favorable outcomes. mrsa colonization did not predict mortality in general (or=1.02; 95%ci=0.35-3.00; p=0.97) or by infectious causes (or=0.96; 95%ci=0.33-2.89; p=0.96). the results suggest that, in the absence of severity of illness factors, colonization with mrsa is not associated with unfavorable outcomes.
Nasopharyngeal Gram-negative bacilli colonization in Brazilian children attending day-care centers
Lima, Ana Beatriz Mori;Le?o, Lara Stefania Netto de Oliveira;Oliveira, Luciana Silva da Cruz;Pimenta, Fabiana Cristina;
Brazilian Journal of Microbiology , 2010, DOI: 10.1590/S1517-83822010000100005
Abstract: this study aimed at determining prevalence and resistance profile of gram-negative bacilli isolated from nasopharynx of children attending day-care centers in goiania (brazil). p. aeruginosa (100.0%), e. coli (50.0%), k. pneumoniae (35.3%), and e. aerogenes (16.7%) were the most frequent multi-drug resistant microorganisms isolated. no production of esbl was detected.
Nasopharyngeal colonization by Haemophilus influenzae in children attending day-care centers, in Ribeir?o Preto, State of S?o Paulo, Brazil
Silva, Maria E.N. Bonifácio da;Silva, Paulo da;Medeiros, Marta I.C.;Neme, Suzel N.;Macedo, Claudia;Marin, José Moacir;
Brazilian Journal of Microbiology , 2006, DOI: 10.1590/S1517-83822006000100006
Abstract: nasopharyngeal carriage of haemophilus influenzae (hi) was studied in 114 healthy children < 3 years old, attending day-care centers (dccs) in ribeir?o preto, state of s?o paulo, brazil. biotype, serotype (by specific antisera and pcr) and antibiotic susceptibility to 14 antibiotics of each isolate were determined. carriage rates of hi were 72.0%. isolates belonged to biotype ii (36.5%), i (21.5%), v (18.2%) and iii (16.1%). the prevalence of encapsulated hi carriers was 3.2% for type f, 1.0% for type b, 1.0% for type d and 1.0% for type e. resistances to trimethoprim-sulphamethoxazole and ampicillin were 46.2% and 10.7% respectively. multidrug resistance was found in 14 (15.0%) of the isolates tested. among the isolates, 13.9% were b-lactamase producers; there were no b-lactamase negative ampicillin resistant isolates. dccs are niches with a high potential for the spread of microorganisms and should be continuously monitored to detect elimination or replacement of h. influenzae type b colonization.
Case-case-control study of risk factors for nasopharyngeal colonization with methicillin-resistant Staphylococcus aureus in a medical-surgical intensive care unit
Melo, Edson Carvalho de;Fortaleza, Carlos Magno Castelo Branco;
Brazilian Journal of Infectious Diseases , 2009, DOI: 10.1590/S1413-86702009000600002
Abstract: nasopharyngeal colonization with methicillin-resistant staphylococcus aureus (mrsa) often precedes the development of nosocomial infections. in order to identify risk factors for mrsa colonization, we conducted a case-case-control study, enrolling 122 patients admitted to a medical-surgical intensive care unit (icu). all patients had been screened for nasopharyngeal colonization with s. aureus upon admission and weekly thereafter. two case-control studies were performed, using as cases patients who acquired colonization with mrsa and methicillin-susceptible s. aureus (mssa), respectively. for both studies, patients in whom colonization was not detected during icu stay were selected as control subjects. several potential risk factors were assessed in univariate and multivariable (logistic regression) analysis. mrsa and mssa were recovered from nasopharyngeal samples from 27 and 10 patients, respectively. independent risk factors for mrsa colonization were: length-of-stay in the icu (odds ratio [or]=1.12, 95%confidence interval[ci]=1.06-1.19, p<0.001) and use of ciprofloxacin (or=5.05, 95%ci=1.38-21.90, p=0.015). the use of levofloxacin had a protective effect (or=0.08, 95%ci=0.01-0.55, p=0.01). colonization with mssa was positively associated with central nervous system disease (or=7.45, 95%ci=1.33-41.74, p=0.02) and negatively associated with age (or=0.94, 95%ci=0.90-0.99, p=0.01). in conclusion, our study suggests a role for both cross-transmission and selective pressure of antimicrobials in the spread of mrsa.
Nasopharyngeal Actinomycosis
Lamia Ouertatani,Yassine Jeblaoui,Salima Kharrat,Samia Sahtout,Ghazi Besbes
Case Reports in Otolaryngology , 2011, DOI: 10.1155/2011/367364
Abstract: Nasopharyngeal actinomycosis is a rarely encountered bacterial infection which usually occurs after nasal trauma or surgery. In some clinical cases, nasopharyngeal actinomycosis has appeared in patients without prior trauma, making diagnosis difficult. Here we present three such cases successfully treated with appropriate dosages of penicillin. One 16-year-old boy with no previous medical antecedents showed an important thickening of the posterior wall of the nasopharynx. A similar nasopharyngeal thickening was found in a 42-year-old woman exhibiting poor dental hygiene. In another 42-year-old woman, nasopharyngeal inflammation was accompanied by multiple right lymphoadenopathies. Like the first two patients, the woman had no prior trauma but did exhibit poor dental hygiene and teeth rottenness. In all three patients, actinomycosis diagnosis was confirmed by anaerobic microbial culturing of the biopsy specimen. Although diagnosis is delayed in patients with no prior trauma, treatment with antibiotics has greatly improved the prognosis for all forms of actinomycosis, and neither death nor deformity is common.
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