Clinical characteristics of Chlamydia pneumoniae infection in children

doi:10.3877/cma.j.issn.1673-5250.2025.06.008

Objective

To analyze the clinical features of Chlamydia pneumoniae pneumonia in children (CPP).

Methods

A total of 174 children with CPP admitted to the Suzhou University Affiliated Children′s Hospital from July 2023 to April 2025 were selected as research subjects. Based on the type of infection, they were divided into two groups, group A (n=96) and group B (n=78). The group B was further categorized into three subgroups according to the types of pathogens: subgroup B1 (n=40, mixed viral/mycoplasma pneumoniae infections), subgroup B2 (n=25, mixed bacterial infections), and subgroup B3 (n=13, mixed viral/mycoplasma pneumoniae and bacterial infections). The clinical manifestations, laboratory test results, and imaging characteristics were compared retrospectively. The study followed the standards set by the Medical Ethics Committee of the Suzhou University Affiliated Children′s Hospital and got the committee′s approval (Approval No. 2025CS134), and informed consent from the children′s guardians were obtained.

Results

①Among 174 children with CPP, 96 cases (55.2%) had isolated CP infection, while 78 cases (44.8%) had mixed infections; the majority were male (64.9%, 113/174) and over 6 years old (90.8%, 158/174), averaging 14 days of illness. All children had cough symptoms, 76 cases (43.7%) had fever, and 138 cases (79.3%) had sputum production. Among children with mixed infections, rhinovirus (HRV) had the highest detection rate (27/78, 34.6%), followed by Staphylococcus aureus (12/78, 15.4%). ②The incidence of wheezing in group A was significantly lower than that in subgroup B1, with the difference reaching statistical significance (P<0.05). In group A, the incidence of moderate fever was significantly higher, whereas the incidence of high fever was significantly lower than that in subgroup B2, and both differences were statistically significant (P<0.05). In addition, the incidence of vomiting in group A was significantly lower than that in subgroup B3, and the difference was also statistically significant (P<0.05). ③Comparisons of white blood cell count (WBC), neutrophil percentage (NEUT%), hs-CRP, alpha-hydroxybutyrate dehydrogenase(α-HBDH), alanine aminotransferase (ALT), and creatine kinase-MB isoenzyme (CK-MB) levels between group A and groups B1, B2, and B3 showed no significant differences (P>0.05). ④Imaging examination results showed that unilateral lung involvement was more common (71.8%, 125/174), with the right lower lobe being the most commonly affected area (19.5%, 34/174), and lesions involving ≥2 lung lobes were observed in 74 cases (42.5%).

Conclusions

The incidence of mixed infections in children with CPP is high. The younger they are, the more likely they are to have mixed infections, which come with more severe symptoms. For children with CPP, we should actively test for pathogens to quickly identify mixed infections and offer targeted treatments.

Key words: Chlamydia pneumoniae pneumonia, Mixed infection, Viruses, Bacteria, Clinical characteristics, Human rhinovirus, Staphylococcus aureus, Child

表1 B组78例CPP患儿的病原体占比比较[例数(%)]

病原体种类	占比
B1亚组
HRV	27(34.6)
RSV	4(5.1)
MP	2(2.6)
hMPV	2(2.6)
Flu A	1(1.3)
HBoV	1(1.3)
HCoV	1(1.3)
PIV	1(1.3)
腺病毒＋MP	1(1.3)
B2亚组
金黄色葡萄球菌	12(15.4)
肺炎链球菌	8(10.3)
卡他莫拉菌	2(2.6)
流感嗜血杆菌	1(1.3)
肺炎链球菌＋流感嗜血杆菌	1(1.3)
金黄色葡萄球菌＋卡他莫拉菌	1(1.3)
B3亚组
HRV＋肺炎链球菌	5(6.4)
hMPV＋金黄色葡萄球菌	1(1.3)
Flu A＋腺病毒＋HRV＋肺炎链球菌	1(1.3)
HRV＋hMPV＋流感嗜血杆菌	1(1.3)
HRV＋流感嗜血杆菌＋卡他莫拉菌	1(1.3)
RSV＋金黄色葡萄球菌	1(1.3)
Flu A＋肺炎链球菌	1(1.3)
HRV＋金黄色葡萄球菌	1(1.3)
MP＋流感嗜血杆菌	1(1.3)

表1 B组78例CPP患儿的病原体占比比较[例数(%)]

病原体种类	占比
B1亚组
HRV	27(34.6)
RSV	4(5.1)
MP	2(2.6)
hMPV	2(2.6)
Flu A	1(1.3)
HBoV	1(1.3)
HCoV	1(1.3)
PIV	1(1.3)
腺病毒＋MP	1(1.3)
B2亚组
金黄色葡萄球菌	12(15.4)
肺炎链球菌	8(10.3)
卡他莫拉菌	2(2.6)
流感嗜血杆菌	1(1.3)
肺炎链球菌＋流感嗜血杆菌	1(1.3)
金黄色葡萄球菌＋卡他莫拉菌	1(1.3)
B3亚组
HRV＋肺炎链球菌	5(6.4)
hMPV＋金黄色葡萄球菌	1(1.3)
Flu A＋腺病毒＋HRV＋肺炎链球菌	1(1.3)
HRV＋hMPV＋流感嗜血杆菌	1(1.3)
HRV＋流感嗜血杆菌＋卡他莫拉菌	1(1.3)
RSV＋金黄色葡萄球菌	1(1.3)
Flu A＋肺炎链球菌	1(1.3)
HRV＋金黄色葡萄球菌	1(1.3)
MP＋流感嗜血杆菌	1(1.3)

表2 A组与B组CPP患儿的年龄比较[岁，M(Q₁，Q₃)]

组别	例数	年龄
A组	96	11(10，13)
B组	78	11(9，13)
B1亚组	40	10(8.8，12)
B2亚组	25	10(8，13)
B3亚组	13	8(6，9)
A组vs B组总体比较(Z值/P值)		－3.51/0.001
A组vs B1亚组(Z值/P值)		－2.46/0.014
A组vs B2亚组(Z值/P值)		－1.70/0.090
A组vs B3亚组(Z值/P值)		－3.56/0.001

表2 A组与B组CPP患儿的年龄比较[岁，M(Q₁，Q₃)]

组别	例数	年龄
A组	96	11(10，13)
B组	78	11(9，13)
B1亚组	40	10(8.8，12)
B2亚组	25	10(8，13)
B3亚组	13	8(6，9)
A组vs B组总体比较(Z值/P值)		－3.51/0.001
A组vs B1亚组(Z值/P值)		－2.46/0.014
A组vs B2亚组(Z值/P值)		－1.70/0.090
A组vs B3亚组(Z值/P值)		－3.56/0.001

表3 A组与B组，B1、2、3亚组CPP患儿的临床症状发生率比较[例数(%)]

组别	例数	发热			喉间痰响	干咳	喘息	鼻塞
组别	例数	低热	中热	高热	喉间痰响	干咳	喘息	鼻塞
A组	96	10(10.4)	23(24.0)	8(8.3)	80(83.3)	16(16.7)	3(3.1)	36(37.5)
B组	78	3(3.9)	19(24.4)	13(16.7)	60(76.9)	18(23.1)	8(10.3)	24(30.8)
B1亚组	40	2(5.0)	14(35.0)	4(10.0)	28(70.0)	12(30.0)	5(12.5)	10(25.0)
B2亚组	25	1(4.0)	1(4.0)	6(24.0)	22(88.0)	3(12.0)	2(8.0)	10(40.0)
B3亚组	13	0(0)	4(30.8)	3(23.1)	10(76.9)	3(23.1)	1(7.7)	4(30.8)
A组vs B组总体比较(χ²值/P值)		2.69/0.101	0.01/0.951	2.82/0.093	1.13/0.289	1.13/0.289	3.7/0.055	0.86/0.353
A组vs B1亚组(χ²值/P值)		1.03/0.310	1.74/0.187	0.10/0.755	3.07/0.080	3.07/0.080	4.48/0.034	1.97/0.160
A组vs B2亚组(χ²值/P值)		0.99/0.321	4.97/0.026	4.76/0.029	0.33/0.568	0.33/0.568	1.19/0.275	0.05/0.819
A组vs B3亚组(χ²值/P值)		1.49/0.222	0.29/0.593	3.24/0.072	0.33/0.568	0.33/0.568	0.68/0.411	0.22/0.637
组别	例数	流涕	呕吐	扁桃体肿大	肺湿啰音	肺干啰音	肺痰鸣音	肺喘鸣音
A组	96	37(38.5)	11(11.5)	44(45.8)	25(26.0)	1(1.0)	10(10.4)	5(5.2)
B组	78	27(34.6)	14(17.9)	32(41.0)	26(33.3)	1(1.3)	8(10.3)	7(9.0)
B1亚组	40	9(22.5)	5(12.5)	17(42.5)	14(35.0)	0(0)	4(10.0)	5(12.5)
B2亚组	25	11(44.0)	4(16.0)	8(32.0)	6(24.0)	0(0)	2(8.0)	1(4.0)
B3亚组	13	7(53.9)	5(38.6)	7(53.9)	6(46.2)	1(7.7)	2(15.4)	1(7.7)
A组vs B组总体比较(χ²值/P值)		0.29/0.593	1.47/0.225	0.41/0.525	1.12/0.293	0.02/0.882	0.01/0.973	0.95/0.335
A组vs B1亚组(χ²值/P值)		3.25/0.072	0.03/0.864	0.13/0.722	1.11/0.293	0.42/0.517	0.01/0.942	2.20/0.138
A组vs B2亚组(χ²值/P值)		0.25/0.619	0.38/0.539	1.55/0.213	0.04/0.835	0.26/0.608	0.13/0.719	0.06/0.804
A组vs B3亚组(χ²值/P值)		1.11/0.291	6.67/0.010	0.31/0.587	2.28/0.131	2.81/0.094	0.29/0.591	0.14/0.713

表3 A组与B组，B1、2、3亚组CPP患儿的临床症状发生率比较[例数(%)]

组别	例数	发热			喉间痰响	干咳	喘息	鼻塞
组别	例数	低热	中热	高热	喉间痰响	干咳	喘息	鼻塞
A组	96	10(10.4)	23(24.0)	8(8.3)	80(83.3)	16(16.7)	3(3.1)	36(37.5)
B组	78	3(3.9)	19(24.4)	13(16.7)	60(76.9)	18(23.1)	8(10.3)	24(30.8)
B1亚组	40	2(5.0)	14(35.0)	4(10.0)	28(70.0)	12(30.0)	5(12.5)	10(25.0)
B2亚组	25	1(4.0)	1(4.0)	6(24.0)	22(88.0)	3(12.0)	2(8.0)	10(40.0)
B3亚组	13	0(0)	4(30.8)	3(23.1)	10(76.9)	3(23.1)	1(7.7)	4(30.8)
A组vs B组总体比较(χ²值/P值)		2.69/0.101	0.01/0.951	2.82/0.093	1.13/0.289	1.13/0.289	3.7/0.055	0.86/0.353
A组vs B1亚组(χ²值/P值)		1.03/0.310	1.74/0.187	0.10/0.755	3.07/0.080	3.07/0.080	4.48/0.034	1.97/0.160
A组vs B2亚组(χ²值/P值)		0.99/0.321	4.97/0.026	4.76/0.029	0.33/0.568	0.33/0.568	1.19/0.275	0.05/0.819
A组vs B3亚组(χ²值/P值)		1.49/0.222	0.29/0.593	3.24/0.072	0.33/0.568	0.33/0.568	0.68/0.411	0.22/0.637
组别	例数	流涕	呕吐	扁桃体肿大	肺湿啰音	肺干啰音	肺痰鸣音	肺喘鸣音
A组	96	37(38.5)	11(11.5)	44(45.8)	25(26.0)	1(1.0)	10(10.4)	5(5.2)
B组	78	27(34.6)	14(17.9)	32(41.0)	26(33.3)	1(1.3)	8(10.3)	7(9.0)
B1亚组	40	9(22.5)	5(12.5)	17(42.5)	14(35.0)	0(0)	4(10.0)	5(12.5)
B2亚组	25	11(44.0)	4(16.0)	8(32.0)	6(24.0)	0(0)	2(8.0)	1(4.0)
B3亚组	13	7(53.9)	5(38.6)	7(53.9)	6(46.2)	1(7.7)	2(15.4)	1(7.7)
A组vs B组总体比较(χ²值/P值)		0.29/0.593	1.47/0.225	0.41/0.525	1.12/0.293	0.02/0.882	0.01/0.973	0.95/0.335
A组vs B1亚组(χ²值/P值)		3.25/0.072	0.03/0.864	0.13/0.722	1.11/0.293	0.42/0.517	0.01/0.942	2.20/0.138
A组vs B2亚组(χ²值/P值)		0.25/0.619	0.38/0.539	1.55/0.213	0.04/0.835	0.26/0.608	0.13/0.719	0.06/0.804
A组vs B3亚组(χ²值/P值)		1.11/0.291	6.67/0.010	0.31/0.587	2.28/0.131	2.81/0.094	0.29/0.591	0.14/0.713

图1 A组与B1、2、3亚组CPP患儿实验室检查指标及病程比较(图1A：外周血WBC；图1B：NEUT%；图1C：hs-CRP；图1D：α-HBDH；图1E：ALT；图1F：CK-MB；图1G：病程)注：A组为单纯CP感染患儿，B1、2、3亚组分别为CP＋病毒＋MP感染患儿，CP＋细菌感染患儿及CP＋病毒＋MP＋细菌感染患儿。CPP为肺炎衣原体肺炎，CP为肺炎衣原体，MP为肺炎支原体。WBC为白细胞计数，NEUT%为中性粒细胞百分比，hs-CRP为超敏C反应蛋白，α-HBDH为α-羟丁酸脱氢酶，ALT为氨酸转移酶，CK-MB为肌酸激酶同工酶MB。ns表示差异无统计学意义(P>0.05)

表4 本研究174例CPP患儿肺部影像学检查结果比较[例数(%)]

项目	发生率
累及范围
单肺	125(71.8)
双肺	31(17.8)
支气管	18(10.4)
病变部位^a
右肺下叶	34(19.5)
左肺下叶	20(11.5)
右肺上叶	18(10.3)
右肺中叶	6(3.5)
左肺上叶	4(2.3)
累及肺叶数量(个)
1	82(47.1)
2	29(16.7)
3	22(12.6)
≥4	23(13.2)

表4 本研究174例CPP患儿肺部影像学检查结果比较[例数(%)]

项目	发生率
累及范围
单肺	125(71.8)
双肺	31(17.8)
支气管	18(10.4)
病变部位^a
右肺下叶	34(19.5)
左肺下叶	20(11.5)
右肺上叶	18(10.3)
右肺中叶	6(3.5)
左肺上叶	4(2.3)
累及肺叶数量(个)
1	82(47.1)
2	29(16.7)
3	22(12.6)
≥4	23(13.2)

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