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 Table of Contents  
Year : 2022  |  Volume : 9  |  Issue : 4  |  Page : 540-547

Etiological profile, prescribing pattern of antibiotics and clinical outcomes of pneumonia patients in a tertiary care hospital in South India during 5-year period

1 Department of Pharmacy Practice, St, Joseph’s College of Pharmacy, Cherthala, India
2 Department of Pulmonology, Lourdes Hospital and Postgraduate Research Centre, Kochi, Kerala, India

Date of Submission22-Oct-2022
Date of Acceptance08-Dec-2022
Date of Web Publication29-Dec-2022

Correspondence Address:
Dr. Siby Joseph
Department of Pharmacy Practice, St, Joseph’s College of Pharmacy, Cherthala 688524, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mgmj.mgmj_205_22

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Background: Pneumonia is one of the most important and serious lower respiratory tract infections, which requires implacable attention. This work aimed to document the causative organisms, antibiotics used, and outcome of pneumonia patients hospitalized in a tertiary care hospital. Materials and Methods: A retrospective study was conducted in the medical departments of a tertiary care teaching hospital for 5 years. Demographic details and clinical details including pertinent laboratory values of patients diagnosed with pneumonia were documented and analyzed using a specifically designed data collection form. Results: The study was conducted on 190 patients. The average age of the study population was 56.7 ± 22.6 years and there was a male preponderance of 111(58.4%) patients. Klebsiella pneumonia was found to be the most frequently isolated pathogen in 12.5% of the sputum culture, followed by Acinetobacter baumannii in 10.22% and Pseudomonas aeruginosa in 9.09%. The most commonly prescribed empirical antibiotics were beta-lactam antibiotics mostly in combination with macrolides for synergy irrespective of Pneumonia Severity Index (PSI) classes. Definitive therapy was classified based on World Health Organization (WHO) Access, Watch, and Reserve (AWaRe) classification of antibiotics, watch category antibiotics were prescribed according to culture report and reserve antibiotics were prescribed only in those cases where watch category antibiotics were resistant. On analyzing PSI of community-acquired pneumonia (176 patients), most of the patients in the study belong to class 4: 61 patients (34.7%) and class 5: 44 patients (25%). For the high-risk patients (PSI class 4 and 5), mortality was approximately 3.8% (4 of 105) and for low-risk patients, there was zero mortality reported within 30 days. Conclusion: Gram-negative bacteria were the major pathogens causing Pneumonia in the study site contradictory to the data from developed countries. Identifications of pathogens and appropriate antibiotic therapy based on PSI score can bring down the duration of hospital stay and mortality of patients with pneumonia.

Keywords: Community-acquired pneumonia, hospital-acquired pneumonia, length of hospital stay, pneumonia severity index

How to cite this article:
Mathew JR, Noyal S, Biju ST, Joseph S, Jose AP. Etiological profile, prescribing pattern of antibiotics and clinical outcomes of pneumonia patients in a tertiary care hospital in South India during 5-year period. MGM J Med Sci 2022;9:540-7

How to cite this URL:
Mathew JR, Noyal S, Biju ST, Joseph S, Jose AP. Etiological profile, prescribing pattern of antibiotics and clinical outcomes of pneumonia patients in a tertiary care hospital in South India during 5-year period. MGM J Med Sci [serial online] 2022 [cited 2023 Feb 7];9:540-7. Available from: http://www.mgmjms.com/text.asp?2022/9/4/540/365991

  Background Top

Pneumonia is one of the most severe resolvable respiratory illnesses in global health but yet kills a child every 20 s. Though many patients recover within a week or two but may last for even several months for a full recovery.[1],[2] Fever, fatigue, cough, chest pain with pleural effusion, and loss of appetite were the clinical features shown in pneumonia patients. Children and the elderly show different presenting features which include abdominal pain, nausea, and headache, nonappearance of one or more prototypical symptoms.[3] Age, the severity of clinical presentations, the presence of other disease conditions, and specific pathogens are risk factors associated with fatality in pneumonia patients.[4]

The spread and mortality rate of pneumonia is higher in the elderly population due to the presence of a higher number of comorbid conditions or impaired host defenses.[5] The basis of pneumonia treatment is empirical antibiotic therapy depending on local microbial susceptibility and resistance.[3] Assessing the severity of pneumonia is an aid for physicians to make better clinical decisions regarding the need for hospital admission, the necessity of intravenous therapy, and the level of monitoring.[6] This work aimed to document the causative organisms, antibiotics used and outcome of pneumonia patients hospitalized in a tertiary care hospital during the 5 years.

Need for the study

There were limited studies on clinical presentations and treatment patterns of Pneumonia in the southern region of India. This study focused on the clinical presentations and treatment response of pneumonia in different age groups and also evaluated the effect of age, gender, and comorbidities on the prevalence of Pneumonia. Such information might help to prevent or ensure better treatment outcomes for Pneumonia in all age groups. This study might help to identify the changes in clinical features and treatment responses during the last five years.

  Materials and methods Top

Study design

A retrospective observational study was conducted for five years (2016–2020) in the medical departments of a tertiary care teaching hospital. The study was carried out in a 600 bedded hospital. The minimum sample size required was found to be 170. This study aimed to document the causative organisms, antibiotics used and outcomes of pneumonia patients admitted to a tertiary care hospital during the five years.

Study population

This study included patients of all age groups who were admitted to medical departments, with a diagnosis of pneumonia. We excluded the patients who were discharged against proper medical guidance.


The data relevant to the study were gathered using a specially created data collection form. Demographics, previous medical history, medication history, pertinent lab results including sputum culture and sensitivity test, and prescription pattern were collected from medical records and the automated database – Mediware System.

Study variables

Background variables of each patient include age, gender, type of pneumonia, clinical profile, X-ray findings, and comorbidities. Other parameters such as tachycardia, hypotension, anemia, hypoxemia, and pleural effusion were taken into consideration for calculating the pneumonia severity index score.

Statistical analysis

The Statistical Package for the Social Sciences (SPSS) was used for the analysis of data. The differences between the two categories were analyzed using an unpaired t-test and The chi-square test is utilized for analyzing the relation between the three variables. The differences were regarded as significant with a P ≤ 0.05.

  Results Top

Demographic details of patients enrolled in the study

The study was conducted on 190 patients. The average age of patients was 56.7 ± 22.6, and there was a male preponderance with 111(58.4%) patients, but a p-value(0.220) so there is no significant difference. Most of the patients in our study were within the age group of 18–65 years, with a total of 86 patients (45.2%) among these 35 were female patients (40.69%). Fewer patients were in the category of age <18, which has only 20 patients (8 female patients) [Table 1].
Table 1: Demographic details

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Types of pneumonia in different age groups

More number of patients were suffering from community-acquired pneumonia (92.6%), followed by aspiration pneumonia (6.8%) and hospital-acquired pneumonia (0.5%), All patients less than 18 years suffered from community-acquired pneumonia (CAP) while the age category of 18–65 years,79 patients had CAP, 6 patients had aspiration pneumonia and 1 had Hospital-acquired Pneumonia (HAP). Patients with ages greater than 65 years had 77 CAP and 7 aspiration pneumonia.

Chest X-ray findings in different age groups

Chest x-ray reports were available for 155 (81.6%) patients. Among these 124 (80%) patients had a unilateral lung infection and 31 (20%) patients had a bilateral lung infection. Unilateral lung infections were seen more in elderly patients (58/155) and adults (53/155) compared to pediatric patients (13/155).

Comorbidities observed in study population

On analyzing the study sample for comorbidities, 113 patients (59.4%) had more than one comorbidity, with 66 male patients and 47 female patients, in whom 28 males and 19 females belong to the category of age 18 to 65 years, 38 males and 28 females were in the category of age greater than 65 years. Patients belonging to the age group <18 years did not have any comorbid conditions.

Clinical profile of patients with pneumonia

Nearly all patients in our study had respiratory symptoms and over 37.4% of patients had non-respiratory symptoms. About 80.5% of the study population presented in the hospital with a cough regardless of age category. Also, other clinical features such as fever, breathlessness, and chest pain were present in 128 (67.4%), 117 (61.6%), and 37 (19.5%) patients respectively [Table 2].
Table 2: Clinical profile of the study population

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Other clinical characteristic findings in our study were blood urea nitrogen (BUN) (≥ 30 mg/dl), arterial pH (< 7.35), sodium level (< 130mEq/L), total count (>11000), neutrophils (> 75%) and erythrocyte sedimentation rate (ESR) (> 20 mm/hr). Out of 190 patients’ arterial pH, less than 7.35 was for 36 (18.9%) patients, BUN greater than/equal to 30 mg/dl for 77 (40.5%) patients, sodium less than 130mEq/L for 35 (18.4%) patients, total count greater than 11000 for 97 (51.1%), neutrophils greater than 75 percent for 105 (55.3%) patients, and ESR greater than 20 mm/hr for 165 (86.8%) patients at the time of admission to discharge [Table 3].
Table 3: Clinical characteristic variables

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Microbial etiology and antimicrobials

The culture and sensitivity test results were available for 86 patients (45.26%) out of 184 cases, and definite microbial etiology could be determined only in 38 cases (20%). Seven patients were suffering from COVID -19. The culture was taken based on the deterioration of symptoms.

Microbial etiology

In this study, Klebsiella pneumonia was found to be the most frequently isolated organism in 12.5% of the sputum culture [11/87], followed by  Acinetobacter baumannii Scientific Name Search .22% (9/87) and  Pseudomonas aeruginosa Scientific Name Search  9.09% (8/87). Also, there was a patient with two microorganisms in sputum (acinetobacter baumannii + Aspergillus species) An increased rate of pseudomonas and acinetobacter infection was found in the elder population whereas infection with klebsiella pneumoniae Scientific Name Search  appeared more commonly in the adult group.

Empirical antimicrobial therapy

Beta-lactam and macrolide antibiotics were the most commonly prescribed empirical antibiotics in the study population. Combination antibiotic therapy was preferred for synergy. But there were about 37% of cases with Beta-lactam as monotherapy. About 32.95% of patients were prescribed beta-lactam–macrolide combination therapy. Other frequently prescribed antibiotics were 2 beta-lactam – macrolide combination (7.95%), beta-lactam – metronidazole combination (5.115%), beta-lactam – fluoroquinolone combination (2.84%), beta-lactam - aminoglycoside combination (2.84%), and beta-lactam- macrolide – aminoglycoside combination (2.84%).

Definitive antibiotic therapy in our study was classified based on the WHO AWaRe classification of antibiotics. Out of 11 cases with Klebsiella pneumonia, there were 5 cases sensitive only to reserve antibiotics and among these 3 cases were sensitive to colistin only. The remaining cases were treated with watch-category antibiotics. Among 9 cases with Acinetobacter boumani, it was found that 5 cases were sensitive to reserve antibiotics but two cases were treated against the culture sensitivity report with watch category antibiotics and in one case colistin was prescribed even though the culture report showed moderate sensitivity to watch category antibiotics. One case of streptococcus pneumonia required reserve antibiotic linezolid and the remaining cases with pseudomonas aeruginosa,  Moraxella More Details,  Escherichia More Details coli (E.Coli), Burkholderia, and Staph aureus were treated with watch category antibiotics as per culture report. Meropenem was prescribed in 2 cases with pseudomonas aeruginosa and one case with Klebsiella pneumonia. Among 38 patients with culture reports 23 cases had an agreement between empirical and definitive therapy. Empirical therapy continued irrespective of culture sensitivity report in 7 cases [Table 4].
Table 4: Definitive antibiotic therapy based on WHO AWaRe classification

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Pneumonia severity index (PSI) scoring

Patients with community-acquired pneumonia were classified based on the Pneumonia severity index. The probability element that led to pneumonia severity index score were as follows; congestive heart failure (26.8), liver disease (3.2%), renal disease (12.1) neoplasm (2.6%), altered mental status (4.2%), cerebrovascular disease (13.7%), tachycardia (9.5%), tachypnea (15.3%), fever (3.7%), hypotension (2.1%), hyperglycemia (10%), anemia (21.1%), hypoxemia (6.8%), and pleural effusion (58.9%). There were 22 patients (12.5%), in Class 1, class 2: 24 patients (13.6%), class 3: 25 patients (14.2%), class 4: 61 patients (34.7%), and class 5: 44 patients (25%).

Pneumonia severity scores and the empirical antibiotics prescribed and outcome of treatment

The clinical status of patients was correlated with the PSI score and it was found that empirical antibiotic selection was based on the severity of the disease condition and synergistic combinations including higher antibiotics were prescribed in PSI class 4 and class 5 patients. The majority of the patients were discharged with improvement in their clinical conditions but 4 patients lost their life within 30 days of treatment for pneumonia. The patients who died during treatment were coming under PSI score IV or V. About 13 patients from different PSI classes were transferred to another hospital as per their request of financial constraints [Table 5].
Table 5: Pneumonia severity scores, empirical antibiotics prescribed, and outcome of treatment in patients with CAP

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Variables related to average length of stay in CAP patients discharged from hospital

On comparing different variables with an average length of stay in community-acquired pneumonia patients, it was found that there was a statistically significant difference between the length of stay of patients with high-risk PSI scores (IV and V) and low-risk patients (I, II, and III) p-value (0.019). Patients with positive sputum culture results required more days of hospitalization compared to patients with negative sputum culture reports and the difference was found to be a statistically significant p-value (0.019). Patients with multilobar pneumonia required more days of hospitalization compared to patients with unilobar pneumonia but the difference was not significant statistically p-value (0.107).

There was a statistically significant difference in the length of stay of patients with combination empirical antibiotic therapy compared to monotherapy P value (0.001). Definitive antibiotic therapy according to culture and sensitivity reports resulted in a reduction in the length of stay compared to the treatment without modifications. P value (0.048). On analyzing the length of stay of patients with comorbidities and without comorbidities it was found that comorbidities contributed to the prolongation of hospital stay but it was not significant statistically [Table 6].
Table 6: Variables associated with an average length of stay in community-acquired pneumonia patients discharged from the hospital

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  Discussion Top

In clinical practice, pneumonia is one of the common infectious diseases and a major reason for the periodic hospital admission. In developing countries, it is the prime cause of morbidity and mortality. So, it is essential to document the causative organisms, antibiotics used, and outcome of treatment. We were also interested in detailing the clinical profile of the population selected in our study and calculating the pneumonia severity index of the patients with CAP.

Our findings


Previous studies showed the male population as a possible factor for increased pneumonia mortality.[5] There was a male preponderance in our study too (58.4%) which corresponds with the result of the study by Felix Gutierrez et al. (62.5% males) Also our findings have similarities with former studies carried out in Europe.[7]

Out of 7 pneumonia death cases in our study, only one patient was female. Lately, identical trends were noticed for coronavirus infection in 2019; men were frequently infected and has greater death rates compared to women.[8] Our study has four male patients a total of 7 coronavirus disease 2019 (COVID-19) patients with pneumonia, and everyone responded positively to the treatment.

Clinical features

Nearly all patients in our study had respiratory symptoms with 80.5% of the study population presenting in the hospital with a cough regardless of age category. In addition, clinical parameters such as fever, breathlessness, and chest pain were present in 128 (67.4%), 117 (61.6%), and 37 (19.5%) patients respectively. Patients greater than 18 years showed a higher rate of chest pain and breathlessness, while younger patients complained frequently of fever and cough.

This is consistent with previous systemic and meta-review by Tha Phai Htun et al, who evaluated clinical characteristics and diagnostic principles to find out pneumonia in adults.[9] They found that cough had discriminating power to diagnose pneumonia even though the medical history and clinical presentation do not have sufficient discriminatory power overall. Respiratory rates as well as a temperature greater than 38°C were also useful markers among clinical signs followed by tachycardia. They found out that a respiratory rate >20 per minute is probably unwell whereas if it is greater than 24/per minute then probable to be critically ill.

The study by Fang et al. also found that 88.4% of patients presented with a cough, and 70.8% have a cough with expectoration and fever in 68.9% of patients.[10]


The etiological agents which cause pneumonia in patients differ geographically. Many types of research had shown that gram-negative organisms are a rare cause of CAP[5] and Streptococcus pneumonia continues to be the most commonly isolated etiological agent of community-acquired pneumonia in western European regions, also in the elder population admitted with community-acquired pneumonia in a few Asian countries.[10] An International retrospective study by Carlos et al. analyzed the complex interaction of age, comorbidities, illness severity, and also pathogen in terms of CAP.[4] When they examined causative organisms for CAP, gram-positive organisms (Streptococcus pneumonia (S.pneumoniae), staphylococcus spp) were the most frequently isolated organism. But in our study, we found contradictory results with klebsiella pneumonia (12.5%), acinetobacter baumannii (10.22%), and Pseudomonas aeruginosa (9.09%) were the common causative organisms. Our study findings are likely to the results of a study by Mayada Osman to analyze the hospital course, etiology, and outcomes of pneumonia patients of 60 years and above in Thailand; they found pseudomonas aeruginosa (50.5%) and klebsiella pneumonia (20.4%) as the most predominant cause of pneumonia.[10]

Pneumonia severity scoring

In a study conducted by Ahn et al.,[11] most of the study population with CAP belongs to classes IV and V, and mortality rates were also higher in classes IV and V, which is consistent with our study. The death rate and duration of hospital stay were higher in PSI class IV and V in our study.

In our study beta-lactam + macrolide were the most commonly used empirical antibiotics irrespective of PSI classes. This is almost identical to the study conducted by Lodise et al.[12] found that Beta-lactam and macrolide combination increases the survival of severely ill patient group than fluoroquinolone monotherapy. Beta-lactam + macrolide + aminoglycoside, and beta-lactam + macrolide + fluoroquinolone were the other empirical antibiotic combinations used in our study. The number of antibiotics prescribed empirically increased from PSI class I to V with higher antibiotics prescribed in class IV and V. While analyzing the definitive therapy it was found that watch category antibiotics were prescribed according to culture report and reserve antibiotics were prescribed only in those cases where watch category antibiotics were resistant.


About 3.7% of patients died in the course of hospital stay and 87.9% of patients got clinically better and discharged, mortality was observed in age categories between 18 to 65 years and greater than 65 years. The age greater than 65 years, cerebrovascular disease, CHF and chronic liver disease continued to exist as a remarkable risk factor for mortality. When comparing with previous studies, the mortality rate was less in our study, the overall mortality rates in other studies ranged between 15% to 26%.[10]These changes in case-mortality rates are probably due to differences between study populations regards to demographics, underlying health conditions, or severity of illness on admission to the hospital.

There are several factors which independently associated with a longer duration of stay in patients with CAP, previously different studies reported various predictors for the length of stay (LOS).[13] Some predictors were directly related to comorbidities while other predictors were related to the social situation of the patient. Predictors of LOS that are associated with the acute disease include deranged blood results, abnormal clinical signs (high fever, respiratory acidosis, low diastolic BP), multi-lobar lung involvement and positive blood culture, and admission to the intensive care unit (ICU). Within the present study, we identified that patients with positive culture reports and high-risk PSI class were associated with increased length of hospital stay. A study by Asti et al.[14] suggested that taking sputum culture for CAP patients is likely to decrease the length of hospital stay this is similar to our study findings. A statistically significant difference in LOS was seen in our study when antibiotics were changed according to the culture report.

There are some limitations in our study

Firstly, this was a retrospective study, unavoidably we experienced some data missing. Also, it was conducted at a single center in south India in hospitalized patients the outpatient details could not be included. In our study we could not interact with the patients, Therefore, the initial antibiotic therapy documented in the study may not be the actual initial antibiotic therapy that the patient received, this is mostly applicable to patients who were transferred from another hospital. The other limitation of our study was the small sample size. In the future, this study can be extended to a multi-center study with a large sample size so that clearer results can be obtained. Also considering a prospective study rather than a retrospective study will reduce the potential source of bias and confounding.

  Conclusion Top

Pneumonia contributes to a significant healthcare burden with a greater impact on developing countries. Our study analyzed causative organisms, antibiotics used and outcomes of pneumonia patients hospitalized in a tertiary care hospital for five years. In our study, we found that gram-negative pathogens are causing pneumonia in our study site contradictory to the results from the Western countries where the majority of pneumonia cases are caused by gram-positive pathogens. Such information may help to prevent or ensure better treatment outcomes in Pneumonia patients in all age groups.

Ethical consideration

The Institutional Ethics Committee approved the study protocol entitled “ To document the causative organisms, antibiotics used and outcomes of a patient with pneumonia admitted to a tertiary care hospital during the five years (2016 - 2020) vide letter no. LH/EC/2020–35. dated 26 November 2020.

Financial support and sponsorship

Not applicable.

Conflicts of interest

There are no conflicts of interest.

  References Top

Kolek V, Jakubec P, Losse S [Diagnostics and treatment of community-acquired pneumonia - simplicity is the key to success]. Vnitr Lek 2018;63:770-5.  Back to cited text no. 1
Thomas K Global burden of pneumonia. Int J Infect Dis 2016;45:1. DOI: https://doi.org/10.1.1016/j.ijid.2016.02.027  Back to cited text no. 2
Grief SN, Loza JK Guidelines for the evaluation and treatment of pneumonia. Prim Care 2018;45:485-503.  Back to cited text no. 3
Luna CM, Palma I, Niederman MS, Membriani E, Giovini V, Wiemken TL, et al. The impact of age and comorbidities on the mortality of patients of different age groups admitted with community-acquired pneumonia. Ann Am Thorac Soc 2016;13:1519-26.  Back to cited text no. 4
Kothe H, Bauer T, Marre R, Suttorp N, Welte T, Dalhoff K; Competence Network for Community-Acquired Pneumonia study group. Outcome of community-acquired pneumonia: Influence of age, residence status and antimicrobial treatment. Eur Respir J 2008;32:139-46.  Back to cited text no. 5
Singanayagam A, Chalmers JD, Hill AT Severity assessment in community-acquired pneumonia: A review. Qjm 2009;102:379-88.  Back to cited text no. 6
Torres A, Peetermans WE, Viegi G, Blasi F Risk factors for community-acquired pneumonia in adults in Europe: A literature review. Thorax 2013;68:1057-65.  Back to cited text no. 7
Jin JM, Bai P, He W, Wu F, Liu XF, Han DM, et al. Gender differences in patients with COVID-19: Focus on severity and mortality. Front Public Health 2020;8:152.  Back to cited text no. 8
Htun TP, Sun Y, Chua HL, Pang J Clinical features for diagnosis of pneumonia among adults in primary care setting: A systematic and meta-review. Sci Rep 2019;9:7600.  Back to cited text no. 9
Osman M, Manosuthi W, Kaewkungwal J, Silachamroon U, Mansanguan C, Kamolratanakul S, et al. Etiology, clinical course, and outcomes of pneumonia in the elderly: A retrospective and prospective cohort study in Thailand. Am J Trop Med Hyg 2021;104:2009-16.  Back to cited text no. 10
Ahn JH, Choi EY Expanded A-DROP score: A new scoring system for the prediction of mortality in hospitalized patients with community-acquired pneumonia. Sci Rep 2018;8:14588.  Back to cited text no. 11
Lodise TP, Kwa A, Cosler L, Gupta R, Smith RP Comparison of beta-lactam and macrolide combination therapy versus fluoroquinolone monotherapy in hospitalized veterans affairs patients with community-acquired pneumonia. Antimicrob Agents Chemother 2007;51:3977-82.  Back to cited text no. 12
Suter-Widmer I, Christ-Crain M, Zimmerli W, Albrich W, Mueller B, Schuetz P; ProHOSP Study Group. Predictors for length of hospital stay in patients with community-acquired pneumonia: Results from a swiss multicenter study. BMC Pulm Med 2012;12:21.  Back to cited text no. 13
Asti L, Bartsch SM, Umscheid CA, Hamilton K, Nachamkin I, Lee BY The potential economic value of sputum culture use in patients with community-acquired pneumonia and healthcare-associated pneumonia. Clin Microbiol Infect 2019;25:1038.e1-9.  Back to cited text no. 14


  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


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