|Year : 2018 | Volume
| Issue : 1 | Page : 7-10
Role of biocard Mycoplasma immunoglobulin M rapid test in the diagnosis of Mycoplasma pneumoniae infection
Ta-Yu Liu1, Hong-Ren Yu1, Wei-Ju Lee2, Chih-Min Tsai1, Kuang-Che Kuo1, Chih-Hao Chang3, Yu-Tsun Su4, Sui-Ching Wang5, Chen-Kuang Niu1, Kai-Sheng Hsieh1
1 Department of Pediatrics, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Graduate Institute of Clinical Medical Sciences, Chang Gung University College of Medicine, Kaohsiung, Taiwan
2 Department of Pediatrics, Chiayi Chang Gung Memorial Hospital, Chiayi, Taiwan
3 Department of Respiratory Therapy, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan
4 Department of Pediatrics, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan
5 Department of Nursing, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan
|Date of Web Publication||5-Apr-2018|
Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital, #123 Ta-Pei Road, Niao-Sung District, Kaohsiung 833
Source of Support: None, Conflict of Interest: None
Background: Mycoplasma pneumoniae is an important pathogenic bacterium that causes community-acquired pneumonia in children. Rapid and dependable laboratory diagnosis of M. pneumoniae infection is important for starting an appropriate antibiotic treatment. Currently, the serological testing for detection of M. pneumoniae immunoglobulin M (IgM) has been used to determine the presence of an acute infection, the results of which, depending on the laboratory facility, are not available immediately. Therefore, an optimal and instant detection method is needed to facilitate a more accurate diagnosis, which leads to the appropriate treatment of patients with M. pneumoniae-related pneumonia and reduces rates of resistance to antibiotics because of their misuse. Aims: Here, we investigated the clinical diagnostic value of a rapid detection kit for M. pneumoniae-specific IgM antibody, the BioCard Mycoplasma IgM rapid test, in the detection of a Mycoplasma infection in children. Material and Method: 44 pediatric patients with clinically suspected Mycoplasma infection were enrolled for study. Result: Among 82 Mycoplasma IgM-positive samples, 51 samples were detected to be positive using the BioCard rapid test. The sensitivity and specifi city of the kit were 62.20% (51/82) and 100% (16/16), respectively. The positive and negative predictive values were 100% (51/51) and 34.04% (16/47), respectively. Conslusion: In conclusion, the BioCard Mycoplasma IgM rapid test provides an accurate point-of-care diagnosis for M. pneumonia infection.
Keywords: Child, immunoglobulin M, Mycoplasma pneumoniae, pneumonia, rapid test
|How to cite this article:|
Liu TY, Yu HR, Lee WJ, Tsai CM, Kuo KC, Chang CH, Su YT, Wang SC, Niu CK, Hsieh KS. Role of biocard Mycoplasma immunoglobulin M rapid test in the diagnosis of Mycoplasma pneumoniae infection. Pediatr Respirol Crit Care Med 2018;2:7-10
|How to cite this URL:|
Liu TY, Yu HR, Lee WJ, Tsai CM, Kuo KC, Chang CH, Su YT, Wang SC, Niu CK, Hsieh KS. Role of biocard Mycoplasma immunoglobulin M rapid test in the diagnosis of Mycoplasma pneumoniae infection. Pediatr Respirol Crit Care Med [serial online] 2018 [cited 2018 Apr 26];2:7-10. Available from: http://www.prccm.org/text.asp?2018/2/1/7/229320
| Introduction|| |
Mycoplasma pneumoniae is a common pathogen that causes community-acquired pneumonia (CAP), particularly in school-aged children and adolescents.,,,M. pneumoniae was discovered in 30% of pediatric CAP and >50% among children aged 5 years or older.,M. pneumoniae-associated pneumonia occurs in all seasons, though more common in the spring and autumn. Although significant cough without rhinorrhea is the classic manifestation, the symptoms include that of severe pneumonia., Furthermore, many patients with bronchopneumonia, whether viral or bacterial, often have a co-infection with M. pneumoniae., Therefore, an optimal detection method is needed to facilitate a more accurate diagnosis.
The identification of M. pneumoniae is difficult because it is hard to culture and has a very low growth rate; thus, culture-based approaches are commonly not helpful clinically. Polymerase chain reaction (PCR) assays for the diagnosis of M. pneumoniae are time-consuming and their availability is limited. Serological testing is now a major diagnostic method for the detection of M. pneumoniae infection. The detection of M. pneumoniae immunoglobulin M (IgM) has been used to determine the presence of an acute infection.
We evaluated the utility of a rapid detection kit for M. pneumoniae-specific IgM antibody, BioCard Mycoplasma IgM rapid test, in the diagnosis of M. pneumoniae in children.
| Patients and Methods|| |
We enrolled patients aged 1.5–14 years who were admitted at Kaohsiung Chang Gung Memorial Hospital. We obtained 98 samples (42 whole blood, 29 sera, and 27 plasma samples) from 44 pediatric patients with clinically suspected Mycoplasma infection. All patients had pneumonia confirmed by chest X-ray. Fever was defined as a body temperature of ≥38.0°C, which was measured using infrared tympanic membrane thermometers. The Institutional Review Board of Kaohsiung Chang Gung Memorial Hospital approved the collection of data from the patients' medical records (103-7061A3).
Mycoplasma infection was diagnosed using M. pneumoniae-specific IgM enzyme immunoassay test (ELISA ImmunoWELL kits, Ben-Bio, San Diego, CA, USA). The kit colorization was always interpreted with direct visual observation by the same pediatrician. The results of BioCard Mycoplasma IgM rapid test (Ani Biotech Oy, Vantaa, Finland) were classified into four color grades [Figure 1]. The results were graded based on the positive line. Grades 0, 1, 2, and 3 represent negative and weakly positive, moderately positive, and strongly positive results, respectively. We also measured complete blood counts (CBCs), C-reactive protein (CRP), alanine aminotransferase, aspartate aminotransferase levels, total duration of fever, total length of hospitalization, and test after illness onset. Demographic characteristics were collected from patient records. Continuous variables were expressed as means ± standard errors. All statistical tests were performed using SPSS software version 19.0 for Windows (SPSS, Inc., Chicago, IL, USA). P < 0.05 was taken to indicate statistical significance.
|Figure 1: The results of BioCard test are classified into four colorization grades. The right and left lines of the BioCard test represent the control line and result of the patient, respectively.|
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| Results|| |
Clinical characteristics of enrolled patients
We obtained 98 samples (42 whole blood, 29 sera, and 27 plasma samples) from 44 patients with clinically suspected Mycoplasma infection. Of these 98 samples, 82 and 16 were detected to be Mycoplasma IgM positive and Mycoplasma IgM negative, respectively, using M. pneumoniae-specific IgM enzyme immunoassay test. The clinical characteristics of the 44 patients, including age, duration of fever, length of hospital stay, and laboratory analysis of blood, liver enzymes, and CRP, are summarized in [Table 1].
|Table 1: Clinical characteristics of the 44 patients with clinically suspected Mycoplasma infection|
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Using Spearman's rank correlation, a highly monotonic relationship was observed in the association among whole blood, serum, and plasma samples (CBC and serum, r = 0.929; CBC and plasma, r = 0.900; and serum and plasma, r = 0.903) [Table 2].
|Table 2: Spearman's rank correlation to test the association between complete blood count, serum, and plasma|
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High correlation between grades of Mycoplasma immunoglobulin M rapid test and titers of Mycoplasma immunoglobulin M for whole blood samples
Due to the unnecessary centrifugation of blood samples, whole blood acts as a more convenient sample for testing Mycoplasma IgM rapid test kits. Hence, we compared BioCard Mycoplasma IgM rapid test and serum Mycoplasma IgM only for whole blood samples. Of the 42 whole blood rapid test samples, 17, 13, 6, and 6 samples were graded 0, 1, 2, and 3, respectively.
Using one-way analysis of variance (ANOVA), a statistically significant relationship was found between BioCard Mycoplasma IgM rapid test for whole blood samples and the distribution of Mycoplasma IgM titer (r = 0.885, P < 0.001) [Figure 2].
|Figure 2: The relationship between the BioCard Mycoplasma immunoglobulin M rapid test and the distribution of Mycoplasma immunoglobulin M titer by using analysis of variance.|
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Mycoplasma immunoglobulin M titers were significantly different among the four grades of BioCard Mycoplasma immunoglobulin M rapid test using whole blood samples
Using ANOVA Tukey's method, 42 whole blood samples were analyzed. Serum Mycoplasma IgM titers were significantly different among the four grades of the rapid test group [Table 3]. Among 42 whole blood samples, the minimum and maximum serum IgM titers were 127.5 U/mL and 6007.1 U/mL for Grades 0 and 3, respectively. The Mycoplasma serum IgM level was 1029.0 U/mL, which was interpreted as the weakest positive result of the rapid test.
|Table 3: Mycoplasma immunoglobulin M titer among the four grades of the rapid test group|
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Clinical application value of BioCard Mycoplasma immunoglobulin M rapid test
Among 82 Mycoplasma IgM-positive samples, 51 samples were detected to be positive using BioCard Mycoplasma IgM rapid test. The sensitivity and specificity of BioCard Mycoplasma IgM rapid test were 62.20% (51/82) and 100% (16/16), respectively, when using Mycoplasma IgM ELISA as the gold standard. The positive and negative predictive values were 100% (51/51) and 34.04% (16/47), respectively [Table 4].
|Table 4: Sensitivity, specificity, positive predictive value, and negative predictive value between Mycoplasma immunoglobulin M (immunoWELL) positive samples and BioCard Mycoplasma immunoglobulin M rapid test|
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| Discussion|| |
In this study, we investigated the utility of a rapid detection kit for M. pneumoniae-specific IgM antibody, the BioCard Mycoplasma IgM rapid test, in the diagnosis of Mycoplasma infection in children. The kit was highly accurate and showed good sensitivity, specificity, and consistency. Point-of-care testing (POCT), known as bedside testing, is defined as a medical diagnostic testing at or near the point of care. Most importantly, POCT is simple to be used at the primary care level and in remote settings without laboratory infrastructures.
POCT using BioCard Mycoplasma IgM rapid test helps facilitate the immediate diagnosis of M. pneumonia infection at bedside using whole blood. Therefore, with this optimal detection method, the appropriate treatment of patients with M. pneumoniae-associated pneumonia could be started, reducing the misuse of antibiotics.
The progression of M. pneumonia infection is often gradual and slow and, in adults, the illness is usually present for more than 1 week before the patient seeks medical assistance. However, our results showed that children with pneumonia caused by M. pneumoniae were mostly admitted to hospital within the 1st week of infection. This may be because fever is the major symptom in children rather than the prolonged cough typically seen in adults infected with M. pneumoniae. Children are therefore brought to the hospital sooner than adults due to the concerns of the caregiver. In a previous study, we reported the initial positivity rate for M. pneumoniae IgM ELISA detection to be about 60%. Many cases of Mycoplasma infection were Mycoplasma IgM negative upon admission. Hence, BioCard Mycoplasma IgM rapid test has the same limitation like M. pneumoniae IgM ELISA. Hence, repeated test is necessary for a more accurate diagnosis for highly suspected condition in clinic.
In addition to using M. pneumoniae-specific IgM antibody for the diagnosis of M. pneumoniae infection, M. pneumoniae rapid antigen test is also used for the detection of M. pneumoniae. Recently, Miyashita et al. reported a commercial rapid antigen kit (Asahi Kasei Pharma Co., Tokyo, Japan) for the detection of M. pneumoniae ribosomal protein L7/L12 using an immunochromatographic antigen assay. The sensitivity and specificity of this rapid antigen test were 57.6% and 91.6%, respectively, as compared to PCR assay. In our study, the sensitivity and specificity of BioCard Mycoplasma IgM rapid test were 62.20% and 100%, respectively, compared with ELISA assay. Therefore, both IgM and antigen can be used for the rapid detection of M. pneumoniae infection.
This study has two limitations. First, the sample size was small. Second, different patients had different blood sampling time in the course of disease. Therefore, some selection bias may be present.
| Conclusion|| |
The present study is the first report that showed BioCard Mycoplasma IgM rapid test as a useful POCT diagnostic tool for M. pneumonia infection, to investigate the utility of a rapid detection kit for M. pneumoniae-specific IgM antibody. The positive rapid test result confirms Mycoplasma infection; however, a negative result cannot exclude Mycoplasma infection. Repeated test may be needed if Mycoplasma infection is highly suspected.
Financial support and sponsorship
This study was supported in part by grants CMRPG8F1811 (CH Chang) and MOST 105-2314-B-182-051-MY2 (HR Yu) from the Ministry of Science and Technology, Taiwan.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]