Neumonía asociada a ventilación mecánica en pacientes con neumonía grave por SARS-CoV-2 / Ventilation associated pneumonia in patients with severe SARS-CoV-2 pneumonia

Introducción: Los pacientes con COVID-19 pueden evolucionar hacia una falla respiratoria aguda grave y requerir ventilación mecánica invasiva (VMI). La complicación más frecuente en estos pacientes es la neumonía asociada a ventilación mecánica (NAVM), con incidencias reportadas más altas que en la época pre-COVID. El objetivo de este estudio es reportar la incidencia, tasa de incidencia y microbiología de la NAVM en pacientes en VMI con COVID-19. Métodos: Se incluyeron a todos los pacientes con neumonía grave y PCR (+) para SARS-CoV-2 que ingresaron y requirieron VMI entre marzo y julio del 2021 en el Instituto Nacional del Tórax (INT). Se recolectaron datos demográficos, clínicos y de laboratorio de la ficha electrónica. Se registraron y caracterizaron los casos de neumonía asociado a la ventilación mecánica. Resultados: Se incluyeron 112 pacientes de los cuales el 42,8% presentó NAVM, con una tasa de incidencia de 28,8/1.000 días de VMI. Los microorganismos aislados más frecuentes fueron Klebsiella pneumoniae (29,6%), Staphylococcus aureus (21,8%) y Pseudomonas aeruginosa (12,5%). Los pacientes que cursaron NAVM estuvieron casi el doble de tiempo en VMI, pero sin presentar aumento de la mortalidad. Conclusión: La NAVM es una complicación frecuente en los pacientes con neumonía grave asociada a COVID-19. La microbiología de estas entidades no ha cambiado respecto a la era pre-pandémica. Estos resultados cobran relevancia en el inicio y suspensión de antibióticos en este grupo de pacientes.

Introduction: Patients with COVID-19 can progress to severe acute respiratory failure and require invasive mechanical ventilation (IMV). The most frequent complication in these patients is ventilator-associated pneumonia (VAP), with higher reported incidences than in the pre-COVID era. The objective of this study is to report the prevalence, incidence rate and microbiology of VAP in patients on IMV with COVID-19. Methods: Patients with severe pneumonia and PCR (+) for SARS-CoV-2 who were admitted to IMV between march and july 2021 at the Instituto Nacional del Tórax (Chile) were included. Demographic, clinical and laboratory data from electronic records were collected. Cases of pneumonia associated with mechanical ventilation were recorded and characterized. Results: 112 patients were included, 42.8% of them presented VAP with an incidence rate of 28.8/1,000 IMV days. The most frequent isolated microorganisms were Klebsiella pneumoniae (29.6%), Staphylococcus aureus (21.8%) and Pseudomonas aeruginosa (12.5%). Patients who underwent VAP spent almost twice as long on IMV, although they had not increase in mortality. Conclusion: VAP is a common complication in patients with severe pneumonia associated with COVID-19. The microbiology of these entities has not changed from the pre-pandemic era. These results become relevant in the initiation and suspension of antibiotics in this group of patients.

Probable caso de reinfección grave por SARS-CoV-2 con coinfección por Legionella pneumophila / Probable case of severe SARS-CoV-2 reinfection with Legionella pneumophila co-infection

Resumen La inmunidad conferida luego de una primera infección por SARS-CoV-2 y el riesgo consiguiente de infección persistente o reinfección no están completamente dilucidados. Existen reportes internacionales de casos de reinfección, incluyendo el primer caso publicado en Sudamérica. Por otra parte, las comunicaciones de casos de coinfecciones han ido en aumento, incluyendo las asociadas a Legionella pneumophila . Presentamos el caso de un varón de 47 años de edad, personal de salud, que luego de cuatro meses de una primera infección por SARS-CoV-2, presenta una neumonía grave, certificándose una nueva infección por SARS-CoV-2 y una coinfección por L. pneumophila mediante detección de antígeno urinario. Fue tratado en UCI, requiriendo ventilación mecánica, dexametaxona y moxifloxacino, con buena respuesta clínica. Actualmente se encuentra en rehabilitación respiratoria y motora.

Abstract The immunity conferred after a first SARS-CoV-2 infection and the consequent risk of persistent infection or reinfection are not fully elucidated. There are reports both in Europe and in North America of reinfection cases, recently highlighting the first case published in South America. On the other hand, reports of co-infections have been increasing, including those associated with Legionella pneumophila . We present the case of a 47-year-old male, health personnel who, after four months of a first SARS-CoV-2 infection, suffers a severe pneumonia certifying a new SARS-CoV-2 infection and a L. pneumophila co-infection by urinary antigen detection. He was treated in the ICU, requiring mechanical ventilation, dexamethasone, and moxifloxacin, with a good response. He is currently in respiratory and motor rehabilitation.

Identificação molecular de amostras de Legionella pneumophila provenientes de fontes ambientais / Molecular identification of samples of Legionella pneumophila from environmental sources

Legionella pneumophila (Lp) é uma bactéria Gram negativa encontrada em ambientes aquáticos naturais e artificiais nos quais a inalação de aerossóis contaminados pode causar uma pneumonia severa conhecida como Doença dos Legionários com taxa de mortalidade de 10% em indivíduos saudáveis. No Brasil há poucas informações a respeito deste patógeno, mas sabe se que a Pneumonia Adquirida na Comunidade foi responsável por 598.668 hospitalizações e 52.776 mortes só no ano de 2017 e acredita-se que uma porcentagem significativa desses casos seja causada pela Lp. Além disso, os casos de legioneloses vêm crescendo ao redor do mundo e um dos fatores associados a isto é o aumento de sistemas artificiais de água e da exposição humana a fontes contaminadas. A única forma de prevenir a doença dos legionários é pelo controle e tratamento destes ambientes artificiais, especialmente aqueles em grandes edifícios. Sendo assim, o objetivo deste estudo foi caracterizar amostras de Legionella spp. provenientes de fontes ambientais previamente identificadas pela Conforlab. O estudo contou com 50 amostras de Legionella spp. isoladas em meio BCYE a partir de diversas fontes ambientais em nove estados brasileiros fornecidas pela empresa Conforlab. A identificação molecular das amostras foi realizada pela técnica Sequence-based Typing que consiste no sequenciamento e análise de sete genes para a obtenção de um Sequence Type (ST)As amostras foram obtidas de amostras provenientes de hotéis, centros comerciais, laboratórios, empresa e indústria. Cerca de 70% das amostras são da região sudeste do país e 50% do estado de São Paulo. Foram identificados 11 STs entre 34 amostras, dos quais oito são previamente descritos e três STs novos (ST2960, ST2962 e ST2963). Dois complexos clonais foram identificados CC-ST1 e CC-ST1642. O novo ST2960 foi identificado em quatro diferentes torres de resfriamento. O sequenciamento genômico foi realizado em duas amostras de Legionella spp. no qual a sequência da amostra 20935 corresponde a espécie Lp enquanto o outro genoma apresentou maior similaridade com a espécie Legionella anisa, sendo essa a segunda espécie do gênero mais encontrada em amostras de água. Como esperado ST1 foi prevalente, pois é amplamente distribuído na maioria dos países, e os outros STs previamente descritos estão associados às legioneloses em outros países. Dado o grande número de casos de pneumonia anualmente, estima-se que ocorra no Brasil cerca de seis mil óbitos por ano devido à doença dos legionários. Portanto, é necessário que medidas de vigilância e controle da presença de Legionella spp. sejam implementadas, além da realização de mais estudos para a maior compreensão deste patógeno no país. (AU)

Legionelosis ocupacional en mayores de 18 años: revisión sistemática / Occupational legionella in adults over 18 years pf age: a systematic review

Resumen El objetivo es revisar la literatura científica sobre los problemas de salud derivados de la exposición laboral a Legionella spp. Revisión sistemática de la literatura científica recogida en las bases de datos MEDLINE (Pubmed), ISI-Web of Science (Institute for Scientific Information), Cochrane Library Plus, Literatura Latinoamericana de Información en Ciencias de la Salud (LILACS) y SCOPUS, hasta febrero 2015. Los descriptores utilizados fueron: "Legionnaires' Disease" "Legionellosis" "Occupational Exposure" "Occupational Diseases". Se obtuvieron 222 referencias, que tras aplicar los criterios de inclusión y exclusión, se seleccionaron 13 artículos a texto completo. De ellos 9 artículos describen la aparición de neumonía, 4 Fiebre de Pontiac, 1 legionelosis o presunta legionelosis y 3 muerte. El principal agente causal en los profesionales expuestos fue Legionella pneumophila serogrupo 1. La infección por legionela está ligada a las profesiones donde existe nebulización por agua, principalmente en los trabajadores sometidos a largas exposiciones o incluso a la re-exposición. Los brotes se producen de forma estacional, sobre todo en los meses más cálidos.

Abstract The scope of this paper is to review the available scientific literature about the effects on health of occupational exposure to Legionella spp. A systematic review of the scientific literature retrieved from the MEDLINE (via PubMed), ISI-Web of Science (Institute for Scientific Information), Cochrane Library, LILCAS and SCOPUS databases through February 2015 was conducted. The key words used were ««Legionnaires' Disease¼ «Legionellosis¼ «Occupational Exposure¼ «Occupational Diseases¼. Two hundred and twenty-two references were retrieved of which, after applying inclusion/exclusion criteria, 13 complete articles were selected. Of these, 9 describe pneumonia, 4 list Pontiac Fever, 1 reveals legionellosis and 3 result in death. The main causative agent of disease in workers exposed was Legionella pneumophila serogroup 1. Legionella spp infection is closely related to professions where there is nebulization with water, mainly among workers subjected to long exposure or even re-exposure. Outbreaks occurs seasonally, especially in the hottest months.

An Investigation on the Molecular Characteristics and Intracellular Growth Ability among Environmental and Clinical Isolates of Legionella pneumophila in Sichuan Province, China / 生物医学与环境科学（英文）

OBJECTIVE@#To investigate the molecular characteristics and intracellular growth ability of Legionella pneumophila (L. pneumophila) strains from 1989 to 2016 in Sichuan Province, China.@*METHODS@#Seventy-nine isolates of L. pneumophila were collected from environmental and clinical sources, including cooling towers, hot springs, bath water, fountains, and patients, and identified with 16S rRNA gene analysis and serum agglutination assay. The isolates were then typed by Sequence-Based Typing (SBT), and Genotyping of forty-two LP1 strains were analyzed by means of multiple-locus VNTR analysis with 8 loci (MLVA-8). All strains were further analyzed for two virulence genes: Legionella vir homologue (lvh) and repeats in structural toxin (rtxA). The intracellular growth ability of 33 selected isolates was determined by examining their interaction with J774 cells.@*RESULTS@#All isolates were identified to L. pneumophila including 11 serogroups, among which the main serogroup were LP1, accounting for 54.43%. Thirty-three different sequence types (STs) from five main clonal groups and five singletons were identified, along with 8 different MLVA patterns. Both the lvh and rtxA loci were found in all 79 strains. Thirty isolates showed high intracellular growth ability in J774 cells.@*CONCLUSION@#L. pneumophila is a potential threat to public health, and effective control and prevention strategies are urgently needed.

An investigation of virulence factors of Legionella pneumophila environmental isolates

ABSTRACT Nine Legionella pneumophila strains isolated from cooling towers and a standard strain (L. pneumophila serogroup 1, ATCC 33152, Philadelphia 1) were analyzed and compared in terms of motility, flagella structure, ability to form biofilms, enzymatic activities (hemolysin, nucleases, protease, phospholipase A, phospholipase C, acid phosphatase, alkaline phosphatase and lipase), hemagglutination capabilities, and pathogenicity in various host cells (Acanthamoeba castellanii ATCC 30234, mouse peritoneal macrophages and human peripheral monocytes). All the isolates of bacteria appeared to be motile and polar-flagellated and possessed the type-IV fimbria. Upon the evaluation of virulence factors, isolate 4 was found to be the most pathogenic strain, while 6 out of the 9 isolates (the isolates 1, 2, 3, 4, 5, and 7) were more virulent than the ATCC 33152 strain. The different bacterial strains exhibited differences in properties such as adhesion, penetration and reproduction in the hosts, and preferred host type. To our knowledge, this is the first study to compare the virulence of environmental L. pneumophila strains isolated in Turkey, and it provides important information relevant for understanding the epidemiology of L. pneumophila.

Use of serology and polymerase chain reaction to detect atypical respiratory pathogens during acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND/AIMS: To use serological and multiplex polymerase chain reaction (PCR) assays to examine sputum samples from patients experiencing acute exacerbation of chronic obstructive pulmonary disease (AECOPD) for the presence of atypical pathogens, including Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila. METHODS: From September 2012 to February 2014, 341 patients with AECOPD attending outpatient clinics were enrolled as part of a randomized, double-blind, multicenter study. A commercial enzyme-linked immunosorbent assay was used to measure serum immunoglobulin M (IgM) and IgG antibody titers on the first day of the study and at 36 days post-enrollment. Multiplex PCR was used to test sputum samples for the presence of atypical pathogens. A urinary antigen test for L. pneumophila was performed on the first day. RESULTS: Nineteen patients (5.6%) showed serological evidence of acute infection with M. pneumoniae. Also, one and seven patients (2%) showed serological evidence of acute infection with C. pneumoniae and L. pneumophila, respectively. All DNA samples were negative for M. pneumoniae, C. pneumoniae, and L. pneumophila according to PCR. Only one urine sample was positive for L. pneumophila antigen, but serologic evidence was lacking. CONCLUSIONS: Serological testing suggested that infection by atypical pathogens during AECOPD was relatively uncommon. In addition, PCR provided no direct evidence of infection by atypical pathogens. Thus, atypical pathogens may not be a major cause of AECOPD in South Korea.

Evaluation of EuDx™-PN MLC Detection Kit for Detection of Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila in Respiratory Specimens / 대한임상미생물학회지

BACKGROUND: Infection by the intracellular bacteria Mycoplasma pneumoniae, Chamydophila pneumoniae, and Legionella pneumophila are common causes of community-acquired pneumonia (CAP). This study describes the evaluation of a new multiplex real-time PCR test, EuDx™-PN MLC Detection Kit (EUDIPIA), which allows the simultaneous detection of M. pneumoniae, C. pneumoniae, and L. pneumophila in respiratory samples. METHODS: A total of 353 samples were tested using three PCR kits: multiplex PCR (Seeplex PneumoBacter ACE Detection Kit) and two multiplex real-time PCR (EuDx™-PN MLC Detection Kit and Anyplex™ II RB5 Detection Kit). The results were considered true positives (expanded standard) for M. pneumoniae, C. pneumoniae, and L. pneumophila if they were positive according to any of the three tests. RESULTS: The sensitivity and specificity of EuDx™-PN MLC Detection Kit were 93.3–100% and 100%, respectively. The agreement rate and Cohen's kappa coefficient (value) between EuDx™-PN MLC Detection Kit and Anyplex™ II RB5 Detection Kit for M. pneumoniae, C. pneumoniae, and L. pneumophila were 70–100% and 0.82–1, respectively. CONCLUSION: These results demonstrate that the EuDx™-PN MLC Detection Kit is a sensitive, specific, and useful screening tool for the detection of atypical pathogens in respiratory samples and can be helpful in selecting appropriate antimicrobial therapy for patients with respiratory infection.

Community-acquired Legionnaires’ Disease in a Newly Constructed Apartment Building / 예방의학회지

OBJECTIVES: Legionnaires' disease (LD) is a severe type of pneumonia caused by inhalation of aerosols contaminated with Legionella. On September 22, 2016, a single case of LD was reported from a newly built apartment building in Gyeonggi province. This article describes an epidemiologic investigation of LD and identification of the possible source of infection. METHODS: To identify the source of LD, we interviewed the patient's husband using a questionnaire based on the Legionella management guidelines from the Korea Centers for Disease Control and Prevention. Water samples from the site were collected and analyzed. An epidemiological investigation of the residents and visitors in the apartment building was conducted for 14 days before the index patient's symptoms first appeared to 14 days after the implementation of environmental control measures. RESULTS: Legionella pneumophila serogroup 1 was isolated from the heated-water samples from the patient's residence and the basement of the apartment complex. Thirty-two suspected cases were reported from the apartment building during the surveillance period, yet all were confirmed negative based on urinary antigen tests. CONCLUSIONS: The likely source of infection was the building's potable water, particularly heated water. Further study of effective monitoring systems in heated potable water should be considered.

Presencia de Legionella spp. en depósitos domiciliarios de agua potable en Resistencia, Chaco, Argentina. Informe preliminar / Presence of Legionella spp. in household drinking water reservoirs in Resistencia, Chaco, Argentina. Preliminary report

Legionella spp. es una bacteria ambiental capaz de sobrevivir en un amplio intervalo de condiciones fisicoquímicas y puede colonizar los sistemas de distribución y almacenamiento del agua potable. Legionella pneumophila es el principal patógeno trasmitido por el agua y produce el 90% de los casos de legionelosis. El objetivo del presente trabajo fue detectar por cultivo la presencia de Legionella spp. en depósitos domiciliarios de agua potable de la ciudad de Resistencia, Chaco. La detección de Legionella en las muestras de agua se realizó por cultivo según lo establecido en la norma ISO 11731:1998. Se analizaron 32 muestras de agua y de 12 (37,5%) de ellas se recuperaron cepas de Legionella spp. La vigilancia de este microorganismo en el agua de consumo humano representa el primer paso para controlar su diseminación hacia huéspedes susceptibles.

Legionella spp. is an environmental bacterium that can survive in a wide range of physicochemical conditions and may colonize distribution systems of drinking water and storage tanks. Legionella pneumophila is the major waterborne pathogen that can cause 90% of Legionnaires' disease cases. The aim of this study was to detect the presence of Legionella spp. in household drinking water tanks in the city of Resistencia, Chaco. The detection of Legionella in water samples was performed by culture methods as set out in ISO 11731:1998. Thirty two water samples were analyzed and Legionella spp. was recovered in 12 (37.5%) of them. The monitoring of this microorganism in drinking water is the first step towards addressing the control of its spread to susceptible hosts.

Implementación de técnica de cultivo para la investigación de Legionella pneumophila en depósitos domiciliarios de agua potable en Resistencia, Chaco / Implementation of cultivation technique for the investigation of Legionella pneumophila in household drinking water Resistencia, Chaco

Legionella pneumophila es una bacteria ambiental capaz de sobrevivir en un amplio intervalo de condiciones físico-químicas y de colonizar los sistemas de distribución y almacenamiento del agua potable. Es el principal patógeno trasmitido por el agua que produce el 90% de los casos de legionelosis. El objetivo del trabajo fue realizar la puesta a punto de la técnica por cultivo para la vigilancia de L. pneumophila en depósitos domiciliarios de agua potable acorde con la normativa internacional. En las muestras de agua analizadas no se obtuvo desarrollo de L. pneumophila; la cepa utilizada como control positivo, permitió constatar la aptitud de los medios utilizados para la detección de este patógeno en las muestras de agua. La vigilancia de este microorganismo en el agua de consumo humano representa el primer paso en pos de abordar el control de su diseminación hacia huéspedes susceptibles

Distribution characteristics of Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila in hospitalized children with acute respiratory tract infection: an analysis of 13 198 cases / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the distribution characteristics of Mycoplasma pneumoniae (MP), Chlamydia pneumoniae (CP), and Legionella pneumophila (LP) in hospitalized children with acute respiratory tract infection (ARTI).</p><p><b>METHODS</b>A total of 13 198 hospitalized children with ARTI were enrolled as study subjects. Whole blood and urine were collected. The passive agglutination was used to detect serum MP-IgM, ELISA was used to detect serum CP-IgM, and immunochromatography was performed to detect urinary LP antigen.</p><p><b>RESULTS</b>Among the 13 198 hospitalized ARTI children, the detection rates of MP, CP, and LP were 25.31%, 12.74% and 3.27%, suggesting that MP had the highest detection rate (P<0.0125). The detection rates of MP in 2013 and 2014 were significantly higher than that in 2012 (P<0.0125). CP had the highest detection rate in 2013, and LP had the highest detection rate in 2014 (P<0.0125). These three pathogens were detected all around the year, and MP had the highest detection rate in all seasons (P<0.0125). The detection rate of mixed infection with three pathogens was 4.35%, and mixed infection with MP and CP was the most common (P<0.0071). Among the children in different age groups, the patients aged 5-16 years showed the highest overall detection rate of three pathogens (P<0.0071). Among the children with different types of ARTI, the children with bronchopneumonia showed the highest overall detection rate of three pathogens (P<0.0045).</p><p><b>CONCLUSIONS</b>MP, CP, and LP, particularly MP, are important pathogens for children with ARTI in the local area. LP infection tends to increase year by year and should be taken seriously in clinical practice.</p>

Factores pronósticos en adultos hospitalizados por neumonía causada por Legionella pneumophila / Prognostic factors in adult patients hospitalized for pneumonia caused by Legionella pneumophila

Introduction: Legionellosis is a multisystem bacterial disease, which causes pneumonia with high mortality in patients with comorbidity and admitted in intensive care units (ICU). Objective: Determine predictors of mortality or ICU admission. Methods: Retrospective follow-up of patients diagnosed with Legionella pneumophila pneumonia in Complexo Hospitalario Universitario de A Coruña. Period 2000-2013 (n = 240). Analysis of multivariate logistic regression was performed. Results: Mean age was 57.2 ± 15.4 years old, 88.3% were male. Average score of comorbidity (Charlson score) was 2.3 ± 2.3. There was a clear seasonal variation. Predominant symptoms were fever (92.5%), dry cough (38.1%) and dyspnea (33.9%). Creatinine clearance was lower than 60 mL/min/1.73 m² in 29.7% and sodium < 135 mEq/l in 58.3%. Admission to ICU rate was 16.3% and 10.8% needs mechanical ventilation. Inhospital mortality rate was 4.6%, rising to 23.1% in patients admitted to ICU. Variables associated to predict ICU admission were age (OR = 0.96), liver disease (OR = 7.13), dyspnea (OR = 4.33), delirium (OR = 5.86) and high levels of lactatedehydrogenase (OR = 1.002). Variables associated with inhospital mortality were Charlson index (OR = 1.70), mechanical ventilation (OR = 31.44) and high levels of lactatedehydrogenase (OR = 1.002). Discussion: Younger patients with liver disease, dyspnea and confusion are more likely to be admitted to ICU. Comorbidity, mechanical ventilation and elevated LDH levels are associated with higher mortality rate.

Introducción: La legionelosis es una enfermedad bacteriana multisistémica, causante de neumonías con mortalidad elevada en pacientes con comorbilidad e ingresos en Unidad de Cuidados Intensivos (UCI). Objetivo: Determinar factores pronósticos de mortalidad o ingreso en UCI. Material y Métodos: Estudio de seguimiento retrospectivo de pacientes diagnosticados de neumonía por Legionella pneumophila en Complexo Hospitalario Universitario de A Coruña (España). Período 2000-2013 (n = 240), con análisis de regresión logística multivariada. Resultados: La edad media fue 57,2 ± 15,4 años, 88,3% fueron hombres. La puntuación media de comorbilidad (score Charlson) fue 2,3 ± 2,3. Existe clara estacionalidad. La clínica predominante fue fiebre (92,5%), tos seca (38,1%) y disnea (33,9%). El 29,7% presentó aclaramiento de creatinina < 60 mL/min/1,73 m² y el 58,3% sodio < 135 mEq/l. Un 16,3% ingresó en UCI, precisando ventilación mecánica invasiva el 10,8%. La mortalidad global fue 4,6% y de 23,1% en ingresados en UCI. Variables asociadas para predecir ingreso en UCI fueron menor edad (OR = 0,96), hepatopatía (OR = 7,13), disnea (OR = 4,33), síndrome confusional (OR = 5,86) y lactato deshidrogenasa elevada (OR = 1,002). Las variables asociadas a mortalidad intrahospitalaria fueron índice de Charlson (OR = 1,70), ventilación mecánica invasiva (OR = 31,44) y cifras elevadas de lactato deshidrogenasa (OR = 1,002). Discusión: Pacientes jóvenes, con hepatopatía, disnea o confusión tienen más probabilidad de ingresar en UCI. Comorbilidad, ventilación mecánica y lactato deshidrogenasa elevada se asocian a mortalidad.

[Contamination of dental scaler water lines with legionella pneumophila, pseudomonas aeruginosa and gram positive cocci]

Dental staff are exposed to aerosols. Water supply of dental units has insignificant bacterial count but the existing water in the waterlines has over 100,000 microorganisms per milliliter. Various types of microorganisms exist in the waterline of dental units. Legionella pneumophila, Pseudomonas aeruginosa and Gram-positive cocci are among the most important ones. Scaling and root planning is a dental procedure carrying a high risk of bacterial contamination. This study aimed to assess water contamination in private dental offices in Isfahan. In this descriptive study, sampling was done in 50 private offices; 10 ml samples of dental unit water were collected from each scaler and a sample from the city tap water as control. We used 3-step PCR for Legionella detection. The extracted DNA was evaluated for the presence of mip gene sequence using spectrophotometry. For detection of Pseudomonas aeruginosa, samples were cultured in Brilliant Green Bile broth. To confirm P. aeruginosa, the grown colonies were cultured in Cetrimide agar medium and presence of P. aeruginosa was re-confirmed with oxidase test. For evaluation of Gram-positive cocci, multiple smeares were prepared and after Gram staining, Gram-positive specimens were cultured in blood agar medium. Data were analyzed using SPSS version 20 and reported in tables and diagrams as number and percentage. None of the control samples were positive for any bacterium. Thirty-two test samples were also negative for the understudy bacteria; but 18 offices tested positive for these bacteria. Our results shows that hazardous bacteria may be present in dental unit biofilm. Special attention must be paid to the cleanliness of water used in dental procedures

Role of Atypical Pathogens and the Antibiotic Prescription Pattern in Acute Bronchitis: A Multicenter Study in Korea

The role of atypical bacteria and the effect of antibiotic treatments in acute bronchitis are still not clear. This study was conducted at 22 hospitals (17 primary care clinics and 5 university hospitals) in Korea. Outpatients (aged > or = 18 yr) who had an acute illness with a new cough and sputum (< or = 30 days) were enrolled in 2013. Multiplex real-time polymerase chain reaction (RT-PCR) was used to detect five atypical bacteria. A total of 435 patients were diagnosed as having acute bronchitis (vs. probable pneumonia, n = 75), and 1.8% (n = 8) were positive for atypical pathogens (Bordetella pertussis, n = 3; B. parapertussis, n = 0; Mycoplasma pneumoniae, n = 1; Chlamydophila pneumoniae, n = 3; Legionella pneumophila, n = 1). Among clinical symptoms and signs, only post-tussive vomiting was more frequent in patients with atypical pathogens than those without (P = 0.024). In all, 72.2% of the enrolled patients received antibiotic treatment at their first visits, and beta-lactams (29.4%) and quinolones (20.5%) were the most commonly prescribed agents. In conclusion, our study demonstrates that the incidence of atypical pathogens is low in patients with acute bronchitis, and the rate of antibiotic prescriptions is high.

Prevalence and Molecular Diversity of Legionella pneumophila in Domestic Hot Water Systems of Private Apartments.

Aims: To determine the prevalence of Legionella spp. in domestic hot water systems and evaluate the molecular diversity among these Legionella spp. Isolates. Place and Duration of Study: Sample collection area was the city of Aqaba, Jordan, between May and December 2012. Sample analysis was done in Ben-Hayyan international laboratories, Aqaba city, and the molecular microbiology laboratories, Taibah University, Saudi Arabia. Methodology: Two hundred (200) water samples were collected randomly from hot water tanks of private apartments, and were tested for the occurrence of Legionella spp. using direct membrane filtration method followed by species identification using Gram stain, the API 20NE biochemical system and the Legionella species latex agglutination test. Genotype characterizations of the Legionella isolates was carried out using DNA extraction followed by RAPD-PCR amplification with OP-A3 primer and analysis of the resulting patterns. Results: Of the 200 samples, 17 (8.5%) were positive for the presence of Legionella spp. A total of 15 (88.2%) out the 17 positive samples were confirmed as Legionella pneumophila, 10 of them were of serogroup 1 and 5 isolates were of serogroup 2-14, the remaining two isolate were Legionella species other than L. pneumophila. RAPD-PCR analysis classified all 17 Legionella isolates into three groups. Serogroup 1 isolates were classified into group A, serogroup 2-14 isolates in group B and Legionella spp. isolates in group C. Group A was further sub-clustered into two subgroups, genotype A1 containing isolates collected from hot water tanks of a temperature set at 25-30°C and A2 containing isolates collected from hot water tanks of a temperature set at 55-80°C. Conclusion: This study showed the colonization of the plumbing systems of private houses by Legionella spp. and demonstrated that the temperature of the water tanks maybe one of the most important factors that affect the genotypic behavior of Legionella pneumophila.

Molecular Characterization of Legionellosis Drug Target Candidate Enzyme Phosphoglucosamine Mutase from Legionella pneumophila (strain Paris): An In Silico Approach

The harshness of legionellosis differs from mild Pontiac fever to potentially fatal Legionnaire's disease. The increasing development of drug resistance against legionellosis has led to explore new novel drug targets. It has been found that phosphoglucosamine mutase, phosphomannomutase, and phosphoglyceromutase enzymes can be used as the most probable therapeutic drug targets through extensive data mining. Phosphoglucosamine mutase is involved in amino sugar and nucleotide sugar metabolism. The purpose of this study was to predict the potential target of that specific drug. For this, the 3D structure of phosphoglucosamine mutase of Legionella pneumophila (strain Paris) was determined by means of homology modeling through Phyre2 and refined by ModRefiner. Then, the designed model was evaluated with a structure validation program, for instance, PROCHECK, ERRAT, Verify3D, and QMEAN, for further structural analysis. Secondary structural features were determined through self-optimized prediction method with alignment (SOPMA) and interacting networks by STRING. Consequently, we performed molecular docking studies. The analytical result of PROCHECK showed that 95.0% of the residues are in the most favored region, 4.50% are in the additional allowed region and 0.50% are in the generously allowed region of the Ramachandran plot. Verify3D graph value indicates a score of 0.71 and 89.791, 1.11 for ERRAT and QMEAN respectively. Arg419, Thr414, Ser412, and Thr9 were found to dock the substrate for the most favorable binding of S-mercaptocysteine. However, these findings from this current study will pave the way for further extensive investigation of this enzyme in wet lab experiments and in that way assist drug design against legionellosis.

Application of three uniplex polymerase chain reaction assays for the detection of atypical bacteria in asthmatic patients in Kuwait

Respiratory infections are known to exacerbate wheezing in many asthmatic patients. We aimed to use molecular methods for the fast detection of Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella pneumophila in respiratory specimens from asthmatic patients in Kuwait. We used uniplex PCR assays to detect the three atypical bacteria in clinical specimens from 235 asthmatic and non-asthmatic patients in Kuwait. A regression analysis was used to identify the risk factors related to the bacterial type. Group comparisons for similarity were conducted and correlation coefficients were calculated using SPSS statistical software. The detection limits using uniplex PCR for C. pneumoniae, L. pneumophila and M. pneumoniae were approximately 1 pg, 2.4 fg and 12 pg of DNA, respectively. M. pneumoniae PCR positivity was more common in asthmatic patients [15%] than in non-asthmatic subjects [9%] [P < 0.05]. A marked difference was observed between patients with acute asthma exacerbation [11%] and patients with chronic [stable] asthma [7%] among Kuwaiti patients; these percentages were 16% for non-Kuwaiti acute asthma patients and 14% for non-Kuwaiti chronic asthma patients [P < 0.201]. There was a weak positive correlation between asthma severity and PCR positivity for M. pneumoniae. The PCR results for C. pneumoniae and L. pneumoniae were found to be statistically insignificant. The results of this study suggest that infection with M. pneumoniae may be related to the exacerbation of asthma symptoms and could possibly be a factor that induces wheezing

Endogenous lipoid pneumonia associated with Legionella pneumophila serogroup 1

Endogenous lipoid pneumonia is an uncommon condition. This is a report of a 29-year-old woman diagnosed with endogenous lipoid pneumonia associated with Legionella pneumophila serogroup 1 infection. The patient's endogenous lipoid pneumonia resolved completely after treatment for Legionella pneumophila infection. This suggests that early diagnosis and aggressive treatment of the underlying infection may prevent any long-term sequelae of lipoid pneumonia.