Diseases Due to Chlamydiaceae

2013 ◽  
Author(s):  
Walter E Stamm

The Chlamydiaceae are obligate intracellular bacteria that produce a wide variety of infections in many mammalian and avian species. Three species belonging to two genera of Chlamydiaceae infect humans: Chlamydia trachomatis, Chlamydophila psittaci, and Chlamydophila pneumoniae. C. trachomatis is exclusively a human pathogen and is transmitted from person to person via sexual contact, perinatal transmission, or close contact in households. C. psittaci, in contrast, is more widely distributed in nature, producing genital, conjunctival, intestinal, or respiratory infections in many avian and mammalian species. C. pneumoniae is a fastidious organism that produces upper respiratory tract infection and pneumonitis in both children and adults. This chapter details the epidemiology, pathogenesis, diagnosis, and treatment of chlamydial diseases. Sexually transmitted diseases, perinatal infections, adult inclusion conjunctivitis, trachoma, and psittacosis are covered. The chapter also includes tables outlining comparative features of the three species and treatment of sexually transmitted diseases caused by C. trachomatis, as well as a figure illustrating the life cycle of Chlamydiaceae.  This review contains 1 highly rendered figure, 2 tables, and 87 references.

1965 ◽  
Vol 63 (1) ◽  
pp. 105-116 ◽  
Author(s):  
W. J. L. Sladen

The Antarctic provides unusually simplified conditions for the study of the persistence and exchange of micro-organisms of the upper respiratory tract. The work reported here was done while the author was in the Falkland Islands Dependencies Survey and the United States Antarctic Research Program.Staph, aureus and Staph, albus persisted in the noses, and a-haemolytic streptococci in the throats of men throughout long periods of isolation and semi-isolation in Antarctica.On the whole, men kept their own strains (phage types) of Staph, aureus despite living in very close contact with each other.Persistent carriers of Staph, aureus (90% or more positive swabs per individual) continued to carry this organism for as long as 2 years in Antarctica. Data from men at Wilkes and Hallett IGY Stations indicated that there was a decrease in the intermittent and occasional carrier rates, resulting in a much lower total carrier rate after 12 months Antarctic isolation.Evidence is presented to suggest that β-haemolytic streptococci had disappeared from throats after 12 months of isolation. It is thought that the absence of upper respiratory infections in these communities is due to absence of the bacterial or viral agents.There is an urgent need for further work on the carriage of micro-organisms in the present unique epidemiological conditions of the Antarctic, and for better laboratory facilities there.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Cheng Lei ◽  
Lisong Yang ◽  
Cheong Tat Lou ◽  
Fan Yang ◽  
Kin Ian SiTou ◽  
...  

Abstract Background Acute respiratory infections (ARIs) are among the leading causes of hospitalization in children. Understanding the local dominant viral etiologies is important to inform infection control practices and clinical management. This study aimed to investigate the viral etiology and epidemiology of respiratory infections among pediatric inpatients in Macao. Methods A retrospective study using electronic health records between 2014 and 2017 at Kiang Wu Hospital was performed. Nasopharyngeal swab specimens were obtained from hospitalized children aged 13 years or younger with respiratory tract diseases. xMAP multiplex assays were employed to detect respiratory agents including 10 respiratory viruses. Data were analyzed to describe the frequency and seasonality. Results Of the 4880 children enrolled in the study, 3767 (77.1%) were positive for at least one of the 13 viral pathogens tested, of which 2707 (55.5%) being male and 2635 (70.0%) under 2 years old. Among the positive results, there were 3091 (82.0%) single infections and 676 (18.0%) multiple infections. The predominant viruses included human rhinovirus/enterovirus (HRV/EV 27.4%), adenovirus (ADV, 15.8%), respiratory syncytial virus B (RSVB, 7.8%) and respiratory syncytial virus A (RSVA, 7.8%). The detection of viral infection was the most prevalent in autumn (960/1176, 81.6%), followed by spring (1095/1406, 77.9%), winter (768/992, 77.4%), and summer (944/1306, 72.3%), with HRV/EV and ADV being most commonly detected throughout the 4 years of study period. The detection rate of viral infection was highest among ARI patients presented with croup (123/141, 87.2%), followed by lower respiratory tract infection (1924/2356, 81.7%) and upper respiratory tract infection (1720/2383, 72.2%). FluA, FluB and ADV were positive factors for upper respiratory tract infections. On the other hand, infection with RSVA, RSVB, PIV3, PIV4, HMPV, and EV/RHV were positively associated with lower respiratory tract infections; and PIV1, PIV2, and PIV3 were positively associated with croup. Conclusions This is the first study in Macao to determine the viral etiology and epidemiology of pediatric patients hospitalized for ARIs. The study findings can contribute to the awareness of pathogen, appropriate preventative measure, accurate diagnosis, and proper clinical management of respiratory viral infections among children in Macao.


PEDIATRICS ◽  
1998 ◽  
Vol 101 (Supplement_1) ◽  
pp. 163-165 ◽  
Author(s):  
Scott F. Dowell ◽  
S. Michael Marcy ◽  
William R. Phillips ◽  
Michael A. Gerber ◽  
Benjamin Schwartz

This article introduces a set of principles to define judicious antimicrobial use for five conditions that account for the majority of outpatient antimicrobial use in the United States. Data from the National Center for Health Statistics indicate that in recent years, approximately three fourths of all outpatient antibiotics have been prescribed for otitis media, sinusitis, bronchitis, pharyngitis, or nonspecific upper respiratory tract infection.1Antimicrobial drug use rates are highest for children1; therefore, the pediatric age group represents the focus for the present guidelines. The evidence-based principles presented here are focused on situations in which antimicrobial therapy could be curtailed without compromising patient care. They are not formulated as comprehensive management strategies. For most upper respiratory infections that require antimicrobial treatment, there are several appropriate oral agents from which to choose. Although the general principles of selecting narrow-spectrum agents with the fewest side effects and lowest cost are important, the principles that follow include few specific antibiotic selection recommendations.


2018 ◽  
Vol 201 (2) ◽  
Author(s):  
Nicholas A. Wood ◽  
Krystal Y. Chung ◽  
Amanda M. Blocker ◽  
Nathalia Rodrigues de Almeida ◽  
Martin Conda-Sheridan ◽  
...  

ABSTRACTMembers ofChlamydiaare obligate intracellular bacteria that differentiate between two distinct functional and morphological forms during their developmental cycle, elementary bodies (EBs) and reticulate bodies (RBs). EBs are nondividing small electron-dense forms that infect host cells. RBs are larger noninfectious replicative forms that develop within a membrane-bound vesicle, termed an inclusion. Given the unique properties of each developmental form of this bacterium, we hypothesized that the Clp protease system plays an integral role in proteomic turnover by degrading specific proteins from one developmental form or the other.Chlamydiaspp. have five uncharacterizedclpgenes,clpX,clpC, twoclpPparalogs, andclpB. In other bacteria, ClpC and ClpX are ATPases that unfold and feed proteins into the ClpP protease to be degraded, and ClpB is a deaggregase. Here, we focused on characterizing the ClpP paralogs. Transcriptional analyses and immunoblotting determined that these genes are expressed midcycle. Bioinformatic analyses of these proteins identified key residues important for activity. Overexpression of inactiveclpPmutants inChlamydiaspp. suggested independent function of each ClpP paralog. To further probe these differences, we determined interactions between the ClpP proteins using bacterial two-hybrid assays and native gel analysis of recombinant proteins. Homotypic interactions of the ClpP proteins, but not heterotypic interactions between the ClpP paralogs, were detected. Interestingly, protease activity of ClpP2, but not ClpP1, was detectedin vitro. This activity was stimulated by antibiotics known to activate ClpP, which also blocked chlamydial growth. Our data suggest the chlamydial ClpP paralogs likely serve distinct and critical roles in this important pathogen.IMPORTANCEChlamydia trachomatisis the leading cause of preventable infectious blindness and of bacterial sexually transmitted infections worldwide. Chlamydiae are developmentally regulated obligate intracellular pathogens that alternate between two functional and morphologic forms, with distinct repertoires of proteins. We hypothesize that protein degradation is a critical aspect to the developmental cycle. A key system involved in protein turnover in bacteria is the Clp protease system. Here, we characterized the two chlamydial ClpP paralogs by examining their expression inChlamydiaspp., their ability to oligomerize, and their proteolytic activity. This work will help understand the evolutionarily diverse Clp proteases in the context of intracellular organisms, which may aid in the study of other clinically relevant intracellular bacteria.


2019 ◽  
Vol 14 (1) ◽  
pp. 34-38
Author(s):  
Julita Gil Cuesta ◽  
Joris Adriaan Frank van Loenhout ◽  
Maria Lourdes de Lara Banquesio ◽  
Masniza Mustaffa ◽  
Debarati Guha-Sapir

ABSTRACTIntroduction and Objectives:Typhoon Haiyan partially destroyed the Ormoc District Hospital in the Philippines. A field hospital was established to replace its outpatient department for 5 weeks. We investigated the reasons for medical consultation in the field hospital.Methods:We described the consultations by sex, age, week, and diagnosis according to the Surveillance in Post-Extreme Emergencies and Disasters system. We compared the number and proportion of upper respiratory tract infections (URTIs) with a control season in 2014.Results:We included 6785 consultations, 55.9% from women. The majority of consultations were communicable diseases (88.2%) followed by noncommunicable (7.1%) and injuries (5.6%). Males suffered more often from injuries than women (66.0% vs 34.0%). Consultations due to injuries decreased from 10.0% in the first to 2.9% in the last week. The most frequent diagnosis over the study period was acute respiratory infections (ARIs) (73.1%), of which 83.0% were children. The number of daily URTIs was higher than in a similar 2014 period.Conclusions:ARI was the most prevalent diagnosis. We recommend ARI treatments being fully accessible after such a disaster. During the first week, injury prevention should focus on adult men. Studies after natural disasters should include control periods to better understand disease distribution, ultimately improving the prioritization in disasters.


2019 ◽  
Author(s):  
Laura K Certain ◽  
Miriam B Barshak

Upper respiratory tract infections are the most common maladies experienced by humankind.1 The majority are caused by respiratory viruses. A Dutch case-controlled study of primary care patients with acute respiratory tract infections found that viruses accounted for 58% of cases; rhinovirus was the most common (24%), followed by influenza virus type A (11%) and corona­viruses (7%). Group A streptococcus (GAS) was responsible for 11%, and 3% of patients had mixed infections. Potential pathogens were detected in 30% of control patients who were free of acute respiratory symptoms; rhinovirus was the most common.2 Given the increasing problem of antibiotic resistance and the increasing awareness of the importance of a healthy microbiome, antibiotic use for upper respiratory infections should be reserved for those patients with clear indications for treatment. A recent study of adult outpatient visits in the United States found that respiratory complaints accounted for 150 antibiotic prescriptions per 1,000 population annually, yet the expected “appropriate” rate would be 45.3 In other words, most antibiotic prescriptions for these complaints are unnecessary. Similarly, a study in the United Kingdom found that general practitioners prescribed antibiotics to about half of all patients presenting with an upper respiratory infection, even though most of these infections are viral.4 This review contains 5 figures, 16 tables, and 82 references. Keywords: infection, airway, sinusitis, otitis media, otitis externa, pharyngitis, epiglottitis, abscess


1934 ◽  
Vol 34 (2) ◽  
pp. 195-202 ◽  
Author(s):  
L. Hoyle

In previous studies of the bacterial flora of the upper respiratory tract and its variations during attacks of acute coryza (Hoyle, 1932), it was found that there was in many cases a striking relationship between the appearance of certain organisms with definite pathogenic properties towards the lower animals, in the upper respiratory tract, and the occurrence of acute infections. This relationship was especially marked in the case of the influenza bacillus, and it was suggested that this organism played a prominent part in the aetiology of upper respiratory infections. The significance of the influenza bacillus in acute coryza has been noted by various workers (Noble, Fisher and Brainard, 1928; Burky and Smillie, 1929; Webster and Clow, 1932; Kneeland and Dawes, 1932), but on the other hand various observers have found the incidence of influenza bacilli in the respiratory tract to be the same in normal health and in acute coryza, and Fleming (1929) and Fleming and Maclean (1930) have devised a technique by means of which they claim to have isolated influenza bacilli in 100 per cent, of normal throats. One possible explanation of these conflicting results may be found in the absence of any very exact criterion of what constitutes a typical influenza bacillus.


Nutrients ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 4 ◽  
Author(s):  
Daisuke Furushima ◽  
Takuma Nishimura ◽  
Norikata Takuma ◽  
Ryo Iketani ◽  
Tomohito Mizuno ◽  
...  

Catechins, phytochemicals contained mainly in green tea, exhibit antiviral activity against various acute infectious diseases experimentally. Clinical evidence supporting these effects, however, is not conclusive. We performed a placebo-controlled, single-blind, randomized control trial to evaluate the clinical effectiveness of consumption of catechins-containing beverage for preventing acute upper respiratory tract infections (URTIs). Two hundred and seventy healthcare workers were randomly allocated to high-catechin (three daily doses of 57 mg catechins and 100 mg xanthan gum), low-catechin (one daily dose of 57 mg catechins and 100 mg xanthan gum), or placebo (0 mg catechins and 100 mg xanthan gum) group. Subjects consumed a beverage with or without catechins for 12 weeks from December 2017 through February 2018. The primary endpoint was incidence of URTIs compared among groups using a time-to-event analysis. A total of 255 subjects were analyzed (placebo group n = 86, low-catechin group n = 85, high catechin group n = 84). The URTI incidence rate was 26.7% in the placebo group, 28.2% in the low-catechin group, and 13.1% in the high-catechin group (log rank test, p = 0.042). The hazard ratio (95% confidence interval (CI)) with reference to the placebo group was 1.09 (0.61–1.92) in the low-catechin group and 0.46 (0.23–0.95) in the high-catechin group. These findings suggest that catechins combined with xanthan gum protect against URTIs.


2018 ◽  
Vol 7 (1) ◽  
pp. 1-7
Author(s):  
Aleksandra Paź ◽  
Magdalena Arimowicz

An estimated 50% of antibiotic prescriptions may be unjustified in the outpatient setting. Viruses are responsible for most acute respiratory tract infections. The viral infections are often self-limiting and only symptomatic treatment remains effective. Bacteria are involved in a small percentage of infections etiology in this area. In the case of a justified or documented suspicion of a bacterial infection, antibiotic therapy may be indicated. Based on the Polish „Recommendations for the management of non-hospital respiratory infections 2016”, the indications, the rules of choice, the appropriate dosing schedules and the therapy duration, in the most frequent upper respiratory tract infections in adults, have been presented. Implementation of the presented recommendations regarding our Polish epidemiological situation, will significantly reduce the tendency to abuse antibiotics, and thus will limit the spread of drug-resistant microorganisms.


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