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ORIGINAL ARTICLE
Year : 2019  |  Volume : 3  |  Issue : 3  |  Page : 176-181

Evaluation of epidemiological and clinical features of patients with pneumococcal and legionella pneumonia


1 Faculty of Medicine, Hamadan University of Medical Sciences, Hamedan, Iran
2 Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

Date of Submission13-Jun-2019
Date of Decision26-Jun-2019
Date of Acceptance10-Jul-2019
Date of Web Publication10-Sep-2019

Correspondence Address:
Dr. Diana Rabooki
Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad
Iran
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/bbrj.bbrj_83_19

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  Abstract 


Background: Pneumonia is one of the major causes of morbidity, mortality, and hospitalization. It is developed by a variety of organisms including Streptococcus pneumoniae and Legionella spp. In this study, the epidemiological and clinical characteristics of patients with Legionella pneumonia (Legionnaires' disease) and pneumococcal pneumonia were compared. Methods: In this crosssectional study, all patients with pneumonia who were hospitalized in Sina Hospital, Hamedan, Iran, were identified. Using blood, sputum, and urine cultures, the patients infected by Streptococcus pneumonia and Legionella pneumonia were isolated. The two groups were compared in terms of the age, sex, clinical signs, risk factors, severity of the disease (using the CURB65 score), and the outcome of the disease. Data were analyzed using SPSS software at 95% confidence level. Results: A total of 30 patients including 17 (56.67%) patients with pneumococcal pneumonia and 13 (43.33%) patients with Legionella pneumonia were included in the study. In the patients with pneumococcal and Legionella pneumonia, the mean and standard deviation of the age were 58.38 ± 20.92 and 56.76 ± 22.49 years, respectively. 23.50% of the patients with pneumococcal pneumonia and 38.50% of the patients with Legionella pneumonia were male (P = 0.376). No statistically significant differences were found between patients with pneumococcal and Legionella pneumonia in terms of clinical symptoms, risk factors, severity of pneumonia based on the CURB65 score, and treatment outcome (P > 0.05). Conclusions: Age and sex distributions of the patients with Legionella and pneumococcal pneumonia were not significantly different. The patients in the two groups were not significantly different in terms of risk factors, clinical symptoms, and disease outcome.

Keywords: Legionella spp., Legionnaires' disease, pneumococcal pneumonia, Streptococcus pneumoniae


How to cite this article:
Rabooki T, Hashemi SH, Rabooki D, Ghasemibasir H, Karami M. Evaluation of epidemiological and clinical features of patients with pneumococcal and legionella pneumonia. Biomed Biotechnol Res J 2019;3:176-81

How to cite this URL:
Rabooki T, Hashemi SH, Rabooki D, Ghasemibasir H, Karami M. Evaluation of epidemiological and clinical features of patients with pneumococcal and legionella pneumonia. Biomed Biotechnol Res J [serial online] 2019 [cited 2019 Sep 23];3:176-81. Available from: http://www.bmbtrj.org/text.asp?2019/3/3/176/266566




  Introduction Top


Pneumonia is one of the important causes of hospitalization and death of elderly patients. It is also a major cause of the mortality in children under 5 years in developed countries. Streptococcus pneumoniae (pneumococcus) and Legionella are considered the most common pathogens that cause pneumonia. Two mentioned bacteria are the major pathogens for emerging of community-acquired pneumonia (CAP) requiring the hospitalization in the intensive care unit (ICU). Pneumonia is categorized into two classes including CAP and hospital-acquired pneumonia (HAP).[1]

In the hospitalized patients, determination of the etiological agents of pneumonia is crucial. Clinical decision for early administration of antimicrobials can affect the mortality and cost of treatment, especially in elderly people.

S. pneumoniae is the most common cause of CAP and meningitis and is a common cause of bacteremia in some parts of the world.[2]

The patients are usually between the ages of 50–60 years. The disease is more common in the winter and spring with typical symptoms including cough, fever, and chest pain. Elderly patients may do not show typical findings and only show tachypnea and decreased consciousness.[3],[4],[5]S. pneumoniae, Haemophilus influenzae, and  Moraxella More Details catarrhalis are among the most common causes of pneumonia in elderly patients. Legionella is also an important agent to cause severe pneumonia in elderly patients.[3],[4],[5] Some Gram-negative bacteria including Pseudomonas species, Staphylococcus aureus, and a combination of aerobic-anaerobic agents are also involved in HAP.[3]S. pneumoniae is the most common microorganism causing pneumonia that may lead to hospitalization of all age groups. It is also known as the most common agent in CAP. S. pneumoniae has been responsible for 75% of pneumonia in recent years.[6]

Various criteria are used to classify the severity of the disease. One of the criteria is CURB65.[6] CURB-65 is a criterion for assessing the severity of pneumonia and considers five factors as follows: reduced level of consciousness and confusion, urea >7 mmol/l (20 mg/dl), respiratory rate ≥30 breaths/min, systolic blood pressure ≤90 mmHg (or diastolic pressure ≤60 mmHg), and age higher than or equal to 65 years. Each item is subject to one score, and the sum of the scores (total score) reaches five Considering to the total score, the patients are divided into three categories including patients who are rated zero that need to have outpatient treatment, the patients with the score between 1 and 3 that need to be admitted to the hospital, and those with the scores higher than 3 that need to be admitted to ICU.[7]

Legionella is responsible for a severe form of pneumonia (Legionnaires' disease) that can be fatal. Among the different species of the bacterium, Legionella pneumophila, serogroup one is responsible for >80% of cases of the infection.[8],[9]

Legionella can be found in air-conditioning and air-cooling systems, which is the major contributor to the infection with the production of L. pneumophila infections. These systems have been the major contributors to the infection through producing the water droplets infected by L. pneumophila.[10],[11]

Occasionally, showers can cause epidemics of Legionnaires' disease in the hospitals. Incinerators and water tanks may also be the source of water droplets infected by the pathogen.[12]

In Legionnaires' disease, there is no direct human-to-human contact. The severity of the disease ranges between a mild fever and a lethal form of pneumonia. The severity of the disease depends on some risk factors such as the age, weakness of the immune system, and smoking.[13]

Considering the importance of pneumonia as a cause for mortality and economic burden, the severity of the disease, and the need for hospitalization in the ICU, identification of common etiological agents and clinical features of the disease is crucial.[14],[15],[16] Hence, in this study, it was an attempt to compare the clinical and epidemiological features of pneumococcal pneumonia and Legionnaires' disease in the patients admitted to Sina Hospital, Hamedan, Iran.


  Methods Top


This study was a randomized cross-sectional study. The Ethics Committee of Hamedan University of Medical Sciences (Hamedan, Iran) provided ethics approval (code: ir.umsha.rec. 1397.466; date of approval: October 16, 2018). The patients with pneumococcal pneumonia and Legionnaires' disease who referred to Sina Hospital (Hamedan, Iran) from April 2018 to September 2018 were included in the study. The patient data remained confidential. The patients were separated into two groups as follows: the patients with pneumococcal pneumonia and the patients with Legionnaires' disease.

The total number of the patients with pneumonia who were admitted to Sina Hospital was 319, of which 30 cases had pneumococcal pneumonia or Legionnaires' disease.

In the first step of this study, all patients who were admitted to the infectious disease ward or ICUs and had pneumonia clinical symptoms (fever, cough, sputum, dyspnea, tachypnea, and loss of consciousness in elderly patients) and abnormal chest radiographs were selected. The ventilator-dependent patients, who had one of the symptoms of fever, tracheal infectious secretions, and crackle in pulmonary auscultation with the evidence of pneumonia, were also included.

Blood, sputum, and urine samples of all patients (319 cases) were collected and cultured to determine the frequency of the patients with pneumococcal or Legionella pneumonia. Brain–heart infusion medium was used for the blood culture. The chocolate agar, blood agar, and EMB media were used for the sputum culture. Blood and sputum samples were cultured for 10 days and 48 h, respectively. To detection of the Legionella urinary antigens, the urine samples were analyzed by ELISA.

Then, the cases with pneumococcal or Legionella pneumonia were investigated in terms of demographic data and general information. Patients' demographic data and general information included age; sex; occupation; smoking; alcohol consumption; drug addiction; underlying disease of heart, lung, kidney, and liver; high blood pressure; malignancy; using immunosuppressants; clinical and radiological symptoms; disease complications; and mortality. The data were recorded using the questionnaires. Moreover, the severity of the disease was determined using the CURB-65 score.

In this study, the inclusion criteria were as follows: pneumonia infection and age over 15 years. The exclusion criteria were as follows: pulmonary embolism, heart infarction, and pulmonary tuberculosis.

SPSS software version 16 was used to analyze the data (SPSS Inc., Chicago, IL, USA). The qualitative and quantitative variables were compared between the two groups. P < 0.05 was considered as statistically significant. The qualitative data were determined using Chi-square test (or Fisher's exact test) and presented as mean ± standard deviation (SD). The qualitative data were analyzed using the Student's t-test and shown as numbers (percentages).

In all steps of this study, the Declaration of Helsinki was considered and all patient information remained confidential. At the beginning of the study, written informed consents were obtained from all patients.


  Results Top


Among 319 patients with pneumonia, thirty patients (9.4%) were detected to undergo pneumococcal pneumonia or Legionnaires' disease. Among them, 17 cases (56.6%) had positive sputum culture and therefore were detected to have pneumococcal pneumonia [Table 1] and [Figure 1]. Thirteen cases (43.33%) had negative sputum culture of common bacteria and positive urinary antigen and were detected to infect by Legionella [Table 1].
Table 1: Results of the blood, sputum, and urine cultures of the patients with pneumonia

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Figure 1: Comparison of the patients with pneumococcal pneumonia and Legionnaires' disease in term of the etiologic agents

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The mean and SD of the patients' age with pneumococcal pneumonia and Legionnaires' disease were 58.38 ± 20.92 and 56.76 ± 22.49 years, respectively. Considering the t-test results, no statistically significant difference was seen between the patients with pneumococcal pneumonia and Legionnaires' disease (P = 0.841) [Figure 2].
Figure 2: Comparison of the patients with pneumococcal pneumonia and Legionnaires' disease in term of age

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Among the patients with pneumococcal pneumonia, four cases (23.5%) were male and 13 cases (76.5%) were female. Among the patients with Legionnaires' disease, 5 cases (38.5%) were male and 8 cases (61.5%) were female. There was no statistically significant difference between the two groups in term of the sex (P = 0.36) [Figure 3].
Figure 3: Comparison of the patients with pneumococcal pneumonia and Legionnaires' disease in term of gender

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The most percentage of the patients was hospitalized in the infectious disease ward (90.0%) and was residence in the urban area (86.7%). All patients had CAP [Table 2].
Table 2: Comparison of the patients with pneumococcal pneumonia and Legionnaires' disease in terms of the admitted ward, residency, and final diagnosis

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Considering [Table 3], there was no statistically significant difference between the patients in the two groups in terms of the risk factors and underlying diseases. Moreover, there was not seen any patient with asthma and splenectomy in the two groups.
Table 3: Comparison of the patients with pneumococcal pneumonia and Legionnaires' disease in terms of the risk factors and underlying diseases

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There was no statistically significant difference between the two groups in terms of the clinical symptoms [Table 4] and CURB-65 score [Table 5] and [Figure 4].
Table 4: Comparison of the clinical symptoms between the patients with pneumococcal pneumonia and Legionnaires' disease

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Table 5: Comparison of the CURB-65 criteria between the patients with pneumococcal pneumonia and Legionnaires' disease

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Figure 4: Comparison of the patients with pneumococcal pneumonia and Legionnaires' disease in term of the CURB-65 score

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In terms of the pneumonia severity based on the CURB-65 score [Table 6] and the Fisher's exact test [Table 7], there was no statistically significant difference between the two groups.
Table 6: Comparison of the patients with pneumococcal pneumonia and Legionnaires' disease in term of the pneumonia severity based on the CURB-65 criterion

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Table 7: Comparison the response to treatment between the patients with pneumococcal pneumonia and Legionnaires' disease

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There was no statistically significant difference between the two groups in the radiographical evaluations [Table 8].
Table 8: Comparison of the radiographic results between the patients with pneumococcal pneumonia and Legionnaires' disease

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  Discussion Top


In this study, thirty patients with pneumococcal pneumonia and Legionnaires' disease were investigated. Seventeen patients (67.66%) had pneumococcal pneumonia and 13 patients (43.33%) had Legionnaires' disease.

In terms of the infection acquisition, all cases in the two groups had CAP.

In some studies, the prevalence of pneumonia in men was higher than women.[17],[18],[19] In the present study, 23.50% of the patients with pneumococcal pneumonia and 38.50% of the patients with Legionnaires' disease were male. There was no statistically significant difference between the etiological agents of pneumonia in males and females.

Patients with pneumonia are usually between 50 and 60 years of age. Pneumococcus, H. influenzae, and M. catarrhalis are among the most common causes of pneumonia in elderly individuals, and Legionella can be a causing agent of severe pneumonia in this group.[3],[4],[5] In the present study, the mean ages of patients with pneumococcal pneumonia and Legionnaires' disease were 58.38 and 56.76 years, respectively. There was no statistically significant difference between the two groups in the term of age. In a study conducted by Barati et al., patients over the age of 18 years who had acute bacterial pneumonia were studied. The mean age of the patients was 55.47.[18] In a study conducted by Ikegame et al., the mean age of such patients was 73.0.[19] The result of the current study in term of the “age” variable was in agreement with the findings by Barati et al.[18]

Here, in terms of the risk factors, in both pneumococcal pneumonia and Legionella pneumonia groups, smoking, hypertension, and heart disease were the most common risk factors. There was no significant difference between the two groups in terms of the mentioned risk factors, chronic obstructive pulmonary disease, malignancy, use of opioid drugs, influenza, alcohol consumption, and liver disease. In a study, Pedro-Botet et al. investigated and compared HIV patients who developed Legionnaires' disease or pneumococcal pneumonia. Their results showed that in HIV patients with Legionnaires' disease, some factors such as smoking and a history of cancer and chemotherapy were significantly more prevalent than that in HIV patients with pneumococcal pneumonia.[20]

Classically, pneumococcal pneumonia initiates with a sudden onset of fever and chills, coughing, unilateral chest pain, and tachypnea. However, in elderly patients, it may appear with some less common symptoms such as confusion or delirium.[7],[19] In this study, cough, sputum, and respiratory distress were the most common clinical symptoms in both pneumococcal pneumonia and Legionnaires' disease groups. There was no statistically significant difference between the two groups in terms of the mentioned clinical symptoms.

In 2019, in a meta-analysis by Khaledi et al., the prevalence of L. pneumophila was evaluated in clinical specimens isolated from the Iranian population. Their results showed that the prevalence of L. pneumophila was 9.6%. The patients' age ranged from 6 months to 80 years. Dyspnea and cough were the most common clinical symptoms of the disease.[21] In a descriptive study, Sawadkohi et al. studied a total of 404 admitted patients who were under the age of 12 years and had pneumonia. Death due to pneumonia was reported in 1.2% of the patients. The clinical symptoms were as follows: positive pulmonary auscultation, cough, fever, and increased respiratory rate.[17] There was no statistically significant difference in the severity of pneumonia based on the CURB-65 score among the patients infected by different etiological agents.

In our study, in the Legionnaires' disease group, 84.60% of the patients had complete recovery of the infection and 15.40% of the patients died. In the pneumococcal pneumonia group, 76.50% of the patients fully recovered, 5.90% of the patients recovered partially, and 17.60% died. There was no statistically significant difference between the two groups in terms of the disease outcome. Although the sample size used in this study was lower than the sample size used by Sawadkohi et al. (30 patients versus 400 patients) and the patients' ages in this study and Sawadkohi study were different (older than 18 years of age versus <5 years old), the results of the two studies were similar.[17]

In a study in 2010, Hung et al. compared the clinical features of patients with pneumococcal pneumonia and Legionnaires' disease. The needs for the intensive care, the necessity for using ventilator, and the rate of mortality in the hospital were similar in the two groups.[22] The results of our study were similar to the mentioned study[22] in terms of the lack of significant statistical difference in the frequency of mortality in the patients with pneumococcal pneumonia and Legionella pneumonia. However, the results of a study conducted by Pedro-Botet et al. showed that the mortality in HIV-positive patients undergoing Legionnaires' disease was higher than the mortality in HIV patients with pneumococcal pneumonia.[20] Their results were in contrary with our results that may be due to the increased risk of death in HIV patients because of the immune deficiencies.

In sum, the distribution of the patients with pneumococcal or Legionella pneumonia in this study in terms of the age and sex was in accordance with the prior published studies. Pneumococcal pneumonia and Legionella pneumonia had similar risk factors and outcomes. Consequently, they were not significantly different from the clinical point of view.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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