Current Pediatric Research

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Research Article - Current Pediatric Research (2020) Volume 24, Issue 7

Lobar pneumonia and bacterial pathogens in Vietnamese children.

Khai Quang Tran1, Van Hung Pham2, Phuong Minh Nguyen1, Hung Do Tran3, Hung Quoc Lu4, Vy Gia Thuy La1, Thang Nguyen5*

1Faculty of Medicine, Can Tho University of Medicine and Pharmacy, Can Tho, Vietnam

2Nam Khoa Biotek Laboratory, Ho Chi Minh City, Vietnam

3Faculty of Nursing and Medical Technology, Can Tho University of Medicine and Pharmacy, Can Tho, Vietnam

4Hanh Phuc An Giang General Hospital, An Giang Province, Vietnam

5Faculty of Pharmacy, Can Tho University of Medicine and Pharmacy, Can Tho, Vietnam

*Corresponding Author:
Thang Nguyen
Faculty of Pharmacy
Can Tho University of Medicine and Pharmacy
179 Nguyen Van Cu Street, Can Tho, Vietnam
Tel: +84968969129
E-mail: [email protected]

Accepted on October 12, 2020

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Abstract

Background: Pneumonia is one of the leading causes of death in children because of its serious clinical manifestations, rapid progress, and a dangerous condition. lobar pneumonia is more severe, more difficult to determine the etiologies if only based on clinical predictors.


Objectives:
To describe the clinical and chest X-ray characteristics of lobar pneumonia; and to determine bacterial pathogens and treatment outcomes in Vietnamese children. Materials and Methods: A cross-sectional study on 67 patients with lobar pneumonia admitted to Children’s Hospital 1, Ho Chi Minh City, Vietnam was conducted. All of nasotracheal aspiration (NTA) specimens of patients were collected and cultured. Real-time PCR was performed to identify bacterial pathogens in NTA specimens.

Results: Lobar pneumonia occurred mainly in children from 3 to 7 years old (46.3%). Clinical manifestations were cough (100%), fever (95.5%), tachypnea (98.5%), lower chest-wall indrawing (53.7%), wheezing (44.8%). Of chest X-ray images, right upper lobe pneumonia was the highest (38.8%), left lower lobe pneumonia (16.4%). The most common bacteria were Mycoplasma pneumoniae (69.7%) and Streptococcus pneumoniae (53%). The original antibiotics mostly used were the 3rd generation cephalosporins (C3G) (50.7%) and C3G + azithromycin (47.8%). 58.2% of cases responded well to the original antibiotics. The successful rate of C3G + azithromycin was 81.2%. The responding of second antibiotics was also high (92.9%), mainly based on the results of real-time PCR. 100% of patients were cured. There were 2 cases with tuberculosis that moved to a tuberculosis hospital for treatment.

Conclusions: Lobar pneumonia can be diagnosed by clinical examination and chest X-ray. Real-time PCR efficient supported in causative pathogens quickly and accurately, guided effective antibiotic therapy, especially in cases of poor clinical responses. Additionally, Mycoplasma pneumoniae was found in a younger group of age than the usual group.”

Keywords

Lobar pneumonia, Children, Bacterial pathogens, Vietnam.

Introduction

Pneumonia is one of the leading causes of death in children because of its serious clinical manifestations, rapid progress, and a dangerous condition [1]. In 2015, an estimated that 900.000 children less than 5 years old died because of pneumonia, with more than 90% of these deaths occurring in low-income and middle-income countries [2]. Between 2000 and 2015, an estimation for children’s hospitalization with pneumonia increased by 2.9 times, which is a more rapid increase in the WHO South-East Asia Region than African Region [3]. The majority (>75%) pneumonia- deaths occurred in six countries: Cambodia, China, Laos, Papua New Guinea, the Philippines. and Vietnam [4]. Lobar pneumonia is a clinical form of pneumonia, which is a common pediatric lower respiratory tract infection [5]. According to the World Health Organization (WHO) 2014, the pneumonia case management approach concentrates on basic clinical signs and symptoms [6]. Meanwhile, lobar pneumonia is more severe, more difficult to determine the etiologies if only based on clinical predictors. Besides, it is difficult to ascertain the relative importance of individual pneumonia pathogens in young children because of the low sensitivity and uncertain specificity of microbiological techniques used for pathogen detection [7]. However, despite the fact that the establishment of accurate etiological diagnosis remains a tremendous challenge, the study aims to use the molecular biology techniques supporting early diagnosis to reduce the mortality.

Polymerase chain reaction (PCR) is a modern technique duplicating one fragment of DNA into millions of them, which has a sensitivity of more than 90% [8]. PCR is one of the tops of methods identifying pathogens and assessing the quantitative of specimens. In Vietnam, however, PCR is still not a common tool in diagnosis because of its high-priced and modernity, which is only used in large hospitals. PCR is an uncommon indication only used in cases that are hard to diagnose and having unresponsive treatment. We, therefore, performed the study to describe the clinical and chest X-ray characteristics of lobar pneumonia; and to determine bacterial pathogens and treatment outcomes in Vietnamese children.

Materials and Methods

Study design

We conducted a cross-sectional study at Children’s Hospital 1 from June 2015 to May 2016.

Study population

The study was performed on 67 patients admitted to the Children’s Hospital 1 where is a large hospital considered as a national first-class pediatric hospital in Vietnam. In-patient children from 2 months to 15 years of age diagnosed with lobar pneumonia were asked to join the research. Children who entered the research of the Children's Hospital 1 met 3 criteria:

Age: 2 months - 15 years old.

Clinical symptoms: Cough, dyspnea, tachypnea by age ± withdraw chest. Tachypnea by age according to WHO: 2 - <12 months: respiratory rate ≥ 50 breaths/minute; 12 months - <5 years: respiratory rate ≥ 40 breaths/minute; and ≥ 5 years: respiratory rate ≥ 30 breaths/minute.

Chest X-ray image: A typical image of lobar pneumonia (relatively homogeneous blurred image occupies one lobe or lobe of the lung and has an inner bronchial airway image) or atypical (shaded blurs are shaped round at an area of the lung, size about 3-4 cm, clear margin, no calcification nodules).

Exclusion criteria: Children’s family refused to join the research group.

N: the minimum sample; α: confidence level (α=0.05);

Z score, ; d: confident limit around the point estimate; P: the rate of lobar pneumonia/pneumonia in Vietnam estimated by Tuan Minh Dao et al. [9] with the P=0.086.

Data collection

Data on demographic, clinical, and subclinical characteristics of inpatients were recorded at the study hospital. NTA specimens were taken by researchers. The children’s mother or relatives carried the children in arms and tilt the head back to facilitate the airway opening. Measuring and marking the distance from the ala of the nose to the earlobe and to the thyroid cartilage. Deeply inserting the catheter into the nose until the marking place, there would be no suction on the way down. Suctioning specimens at the moment that the patients were coughing- blushing and when the catheter reaches the marking place. Slowly taking the catheter out, do not twisting and suctioning along the way. Then rinsing out the catheter with saline (5ml). Taking away the catheter and covering by the cap, bringing the NTA to the lab. If for any reason that the specimens cannot be used immediately, they could be stored at the temperature between 2-8°C, but not more than 2 hours.

The NTA specimens were sent to 2 places: Microbiology Department of Children's Hospital 1 for cultivation and Nam Khoa Biotek Laboratory for PCR, where has the high qualified lab in Vietnam got certificate ISO 17025. BIO RAP.CFX96 machine (made in the USA) was used to run Realtime PCR for the NTA specimens.

The quality of NTA was checked at labs according to Bartlett score [10]. The score is derived from a microscopic exam of sputum specimens that looks at 10x field; (1) the number of neutrophils, (2) the presence of mucus strands, and (3) the number of squamous epithelial cells.

10-25 neutrophils: +1

>25 neutrophils: +2

Columnar cell (+): +1

10-25 squamous epithelial cells: -1

->25 squamous epithelial cells: -2

A score of 0 or less indicates unreliable; 1-2: medium reliability; and >=3: high reliability.

Data analysis

All children who met the sampling criteria were included in the study batch. We performed sample medical records and treated according to hospital regimens; proceeded to take NTA (done by the researcher), sent those specimens to the Microbiology Department of Children's Hospital 1 for screening, transplanting, and Nam Khoa Biotek Laboratory for PCR. The cultivation was done in 2 days and the PCR results returned in 24 hours. After microbiological results, if the agent was isolated, we treated according to the agent. If not isolated, we treated according to clinical practice guidelines and based on the local epidemiology of these infections. Evaluating treatment results through the number of days of treatment and whether or not there was death.

Statistical analysis

The data were analyzed with SPSS statistical software for Windows version 18. The differences between patients’ characteristics and positions of chest radiograph injury were analyzed by the chi-squared test with a 95% confidence interval. A p-value of less than 0.05 was considered significant.

Ethical approval

Ethical approval followed an assessment by Children's Hospital 1 and Can Tho University of Medicine and Pharmacy.

Results

Supportive cases

In our study, most children do not need breathing support (accounted for 91.0%). 7.5% of children need breathing through a cannula, 1.5% of children need NCPAP (Nasal Continuous Positive Airway Pressure) and no children need mechanical ventilation.

Demographic, clinical, and subclinical characteristics

67 children enrolled in the study. The average age of the study sample was 60.9 ± 35 months, the smallest was 7 months and the oldest was 136 months. The most common age group was 3-7 years old (46.3%), less common in children <12 months old (6.0%). This difference was statistically significant (p < 0.001). The incidence in boys and girls was almost the same (p=0.903) (Table 1).

Characteristics Number (N=67) Percentage (%) p-value
Age < 12 months 4 6 p<0.001
12 ? 35 months 15 22.3
36 ? 84 months 31 46.3
> 84 months 17 25.4
Sex Boys 34 50.7 p=0.903
Girls 33 49.3

Table 1. Patient characteristics.

With the clinical findings, the most common symptoms were cough and fever, accounted for 100% and 95.5% of 67 cases. Tachypnea accounted for almost an absolute rate in the group of physical symptoms (98.5%). According to the radiological findings on chest X-rays, single lesions of one lung lobe accounted for the majority (88.0%), the most lesion was in the right lung (64.2%), and especially in the right upper lobe (38.8%). The difference in lesion between positions was statistically significant (p<0.001) (Table 2 and Table 3).

Symptoms Cases (N=67) Percentage (%)
Cough 67 100
Fever 64 95.5
Vomiting 29 43.3
Diarrhea 4 6
Abdominal pain 2 3
Headache 1 1.5
Dyspnea 2 3
Tachypnea 66 98.5
Chest in-drawing 36 53.7
Accessory muscle used 25 37.3
Wheezing 30 44.8

Table 2. Clinical symptoms of patients.

Traumatic position Frequency (N=67) Percentage (%) Cumulative rate (%)
Right upper lobe 26 38.8 38.8
Right lower lobe 10 14.9 53.7
Middle lobe 2 3.0 56.7
Left upper lobe 10 14.9 71.6
Left lower lobe 11 16.4 88.0
2 lobes on one side of the lungs 5 7.5 95.5
2 lobes of lungs 3 4.5 100
p-value p < 0.001

Table 3. Imaging chest trauma.

Bacterial pathogens

In 67 cases of lobar pneumonia taken NTA samples, 1 NTA sample was not reliable enough for transplanting (Barlett score=0 for screening), the remaining 66 samples were inoculated at the Microbiology Department of Children's Hospital 1 and done Realtime PCR at Nam Khoa Biotek Laboratory. With 66 samples inoculated, 100% cases gave negative results. With 66 samples sent as real-time PCR, there were 2 samples returned negative, the remaining 64 samples are positive, accounting for 97.0%.

In 64 positive PCR samples, there were 2 cases of Mycobacterium tuberculosis, transferred to Pham Ngoc Thach Hospital - a hospital specializing in the treatment of pulmonary tuberculosis in Ho Chi Minh City, Vietnam.

The PCR result was called positive when there was 1 agent detected > 105 copies/ml. We evaluate the main agent and the co-infection agents in cases of many positive agents on an NTA sample. The main agent is the agent detected with the highest number of copies/ml. Through 66 times of isolation for each agent, we recorded Mycoplasma pneumoniae accounted for the highest proportion of 69.7% (both being the main agent in 35 times of isolation and both as a co-infection agent in 11 isolation times), following after were Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, and Mycobacterium tuberculosis (Table 4). In 9 cases of Haemophilus influenzae, only 1 case was identified as Haemophilus influenzae type b. However, in this case, Haemophilus influenzae type b was not the main agent. In 18 isolated cases of Staphylococcus aureus, there were 11 cases of Methicillin-resistant Staphylococcus aureus (5 strains with MecA gene, 3 strains with Nuc and 3 strains carrying FemA gene). But all 11 cases were not the major factor. With 2 cases of tuberculosis detection, the result was both negative firstly, we changed/added antibiotics but clinically still did not respond. We decided to isolate with Mycobacterium tuberculosis, a positive result with a high number of copies.

Bacterium Positive isolation Negative, N (%) Total (N)
Main agent (N) Co-infection agent (N) Positive, N (%)
Mycoplasma pneumoniae 35 11 46 (69.7%) 20 (30.3%) 66
Streptococcus pneumoniae 19 16 35 (53%) 31 (47%) 66
Staphylococcus aureus 5 13 18 (27.2%) 48 (72.8%) 66
Haemophilus influenzae 3 6 9 (13.6%) 57 (86.4%) 66
Moraxella catarrhalis 0 5 5 (7.6%) 61 (92.4%) 66
Mycobacterium tuberculosis 2 0 2 (3%) 64 (97%) 66
All pathogens causing lobar pneumonia identified by using real-time PCR
1. Streptococcus pneumoniae
2. Streptococcus agalactiae
3. Streptococcus pyogenes
4. Mycoplasma pneumoniae
5. Mycoplasma sp.
6. Haemophilus influenzae
7. Haemophilus influenzae type b
8. Staphylococcus aureus
9. Staphylococcus aureus has FemA gene
10. Staphylococcus aureus has Nuc gene
11.