Clinical characteristics from co-infection with avian influenza A H7N9 and Mycoplasma pneumoniae: a case report
More and more cases of human infections with avian influenza A H7N9 have been reported since it was first mentioned in 2013 in China, but concurrence of influenza A H7N9 with Mycoplasma pneumoniae, however, has never been described. Here, we reported the case of a woman co-infected by influenza A H7N9 and Mycoplasma pneumoniae, whose treatment process was a little bit longer and a little bit complicated as well.
Our patient was an 80-year-old Chinese woman who presented with fever, cough, chest tightness, and shortness of breath. A computed tomography scan showed obvious infiltrations at lower parts of both lungs. Arterial blood gas analysis confirmed a severe respiratory failure (type I). Her sputum and throat swabs were checked for nucleic acid of influenza A and the result was positive for influenza A H7N9. She was diagnosed as having severe influenza A H7N9 and acute respiratory distress syndrome, and was admitted to an intensive care unit. She was given comprehensive treatment, including oseltamivir, methylprednisolone, immunoglobulin, gastric protection, and noninvasive mechanical ventilation. Her condition improved 4 days later. However, some symptoms exacerbated again 2 days later with ground-glass changes appearing in upper area of right lung and the titer of antibody to Mycoplasma pneumoniae rising from 1:80 to 1:640. She was reasonably considered to be infected with Mycoplasma pneumoniae as well, and azithromycin and moxifloxacin were added to her treatment. Oseltamivir was discontinued because of three consecutive negative results of nucleic acid for influenza A H7N9, but anti-Mycoplasma treatment was continued. Although her symptoms and abnormal changes on computed tomography scan slowly went away, she finally recovered from the mixed infection after a total of 33 days of management.
In patients with confirmed influenza A H7N9 infection whose condition worsens again, especially with new infiltration or lung ground-glass infiltration, one should suspect infection by other pathogens such as Mycoplasma pneumoniae.
KeywordsAvian influenza A H7N9 Mycoplasma pneumoniae Co-infection Case report
Acute respiratory distress syndrome
Beats per minute
Chronic obstructive pulmonary disease
Fraction of inspired oxygen
Intensive care unit
Carbon dioxide arterial tension
Oxygen arterial tension
Since the case of human infection with avian influenza A H7N9 was first reported in 2013 in China , many more cases of this disease have emerged in this country [2, 3]. Human infection with avian influenza A H7N9 is a kind of acute respiratory disease which is caused by avian influenza A H7N9 virus, with more than 90% of the infected patients presenting with rapidly progressive pneumonia and 70% of them presenting with acute respiratory distress syndrome (ARDS). The mortality is as high as 30% .
Patients with influenza A H7N9 often have some underlying diseases including chronic obstructive pulmonary disease (COPD), hypertension, diabetes mellitus, and heart diseases , which make patients prone to infection by some other pathogens, such as bacteria. However, concurrence of influenza A H7N9 virus and Mycoplasma pneumoniae (MP) infection has never been described.
MP pneumonia is an atypical community-acquired pneumonia, which is most often mild and moderate, and its prognosis is usually good . Here, we report a case with comorbidities of influenza A H7N9 and MP pneumonia, which made our patient’s treatment process a little bit longer.
Our patient is an 80-year-old retired worker, whose onset started with a fever, cough, abdominal distention, weakness, and anorexia. Then, chest tightness and short of breath followed. A computed tomography (CT) scan and arterial blood gas analysis confirmed the diagnosis of severe pneumonia and a respiratory failure (type I) for our patient. She was diagnosed with influenza A H7N9 by positive result of nucleic acid for influenza A H7N9 from sputum and throat swabs 10 days later and was transferred to an intensive care unit (ICU) in Second Affiliated Hospital of Guizhou Medical University, Kaili City, Guizhou Province, China. During her treatment process, she was confirmed to have an infection of MP.
Since this is the first report of influenza A H7N9 complicated with MP, and the anti-MP treatment in such cases might be different from that in MP infection alone, it is valuable to present our case report, sharing our experiences in this patient’s treatment. The main clinical characteristics of our patient and her treatment practice are reported below.
The main diagnoses at ICU admission were severe pneumonia and ARDS.
After being delivered to the ICU, our patient was given comprehensive treatments, including antibiotics, intravenously administered methylprednisolone (120 mg/day), immunoglobulin (10 g/day), and gastric protection. Oseltamivir at 300 mg/day was orally administered for the first 6 days, then at 150 mg/day for the following 3 days. As she was conscious and very cooperative, she was given noninvasive mechanical ventilation (PHILIPS Respironics V60, Respironics California, Inc, USA). Her input of fluid volume was strictly limited and her hemodynamics were stable except for occasional slight fluctuations. After having been treated for 4 days, her respiratory symptoms began to alleviate, and oxygenation improved with PaO2 up to 66 mmHg (FiO2 0.4), and respiratory rate decreasing to 24 to 28 breaths per minute. However, 2 days later, she began to cough with less sputum, and tachypnea and weakness were exacerbated. The titer of MP antibodies gradually increased from 1:80 to 1:160, and then arrived at 1:640 within 9 days. A CT scan on January 26, 2017 revealed an enlarged ground-glass infiltrate in the upper area of her right lung (Fig. 1b). She was reasonably considered to be over-infected with MP, and then orally administered azithromycin (0.5 g/day) and intravenously administered moxifloxacin (400 mg/day) were prescribed on January 23, 2017. At the same time, oseltamivir was discontinued because of three consecutive negative results of nucleic acid for influenza A H7N9. After 5 to 6 days of anti-MP treatment, her symptoms alleviated and the titer of the antibodies decreased. A gradual reabsorption of ground-glass infiltrates was seen in upper lobe of her right lung after 9 days of treatment against MP (Fig. 1c). She was discharged on February 5, 2017 with mild cough and shortness of breath on exercises.
Main clinical process of the first case co-infected by avian influenza A H7N9 and mycoplasma pneumoniae in Kaili, Guizhou province, China
Clinical major events
5 January, 2017
Fever, cough, abdominal distention, weakness, anorexia
11 January, 2017
Went to see doctor, and sputum and throat swabs were collected to be checked for the presence of avian influenza virus
13 January, 2017
Admitted to Second Affiliated Hospital of Guizhou Medical University, CT scan showed obvious consolidation and infiltration in bilateral lungs and ground-glass changes in upper area of right lung; and she was diagnosed with pneumoniae, Oseltamivir and meropenem were administered
14 January, 2017
Result of neucleic acid testing for H7N9 was positive and the patient was transferred to ICU because of illness deterioration and ARDS. Non-invasive MV. Titer of antibody to mycoplasma pneumoniae was 1:80;
18 January, 2017
CHest X-ray showed the infectious focus of bilateral lung partially absorbed.
19 January, 2017
Cough again with fewer sputum, other symptoms exacerbated again, increase of moist rale in upper area in right lung; Titer of antibody to mycoplasma pneumoniae rised to 1:160;
23 January, 2017
CT scan showed new focus appearing in upper aera while old infultration being absorbed. Titer of antibody to mycoplasma pneumoniae arrived to 1:640, and azithromycin and moxifloxacin were administered.
23 January, 2017
Oseltamivir was discontinued because of three continual examinations of neucleic acid for influenza A H7N9 changed to negative
26 January, 2017
CT scan shground-glass focus enlarged comparing to that at 12 days before.
29 January, 2017
The titer of the antibody decreased to 1:320.Patient’s symptoms were alleviated and moist rales reduced
4 February, 2017
CT scan revealed the right upper focus obviously absorbed. Moxifloxacin was discontinued while azithromycin was till continued.
5 February, 2017
Discharged from hospital.
7 February, 2017
Titier of antibody to M. pneumoniae decreased to 1:80.
13 February, 2017
All symptoms disappeared and azithromycin discontinued.
Our patient suffered from avian influenza A H7N9 maybe because of contact history of live birds and her condition exacerbated in a short time. In her treatment process, she was confirmed to be over-infected by MP, which has not been reported before. The anti-MP process in this patient was longer than usual because of her poor underlying condition.
Until now, human infection with avian influenza A H7N9 has been merely confirmed to be associated with exposure to poultry . This was the case for our patient, who had been to a poultry market and had eaten chicken prior to the onset of illness. Surprisingly, her husband, who went to the market with her and had closer contact with the live poultry, remained healthy. This may be associated with his relatively perfect immune system and with no obvious underlying diseases. By contrast, his wife suffered from some underlying illnesses including hypertension and COPD, which made her more susceptible to infection from other pathogens such as avian influenza A H7N9 virus.
Clinical studies have demonstrated that a proportion of patients with influenza A or B are simultaneously infected by other pathogens such as bacteria and aspergilla [3, 7, 8] because of some risk factors such as COPD, use of steroids, and diabetes mellitus or even with a immunocompetent status . But as far as we know, the clinical condition of co-infection caused by influenza A H7N9 and MP has not been described before. Although “atypical” pneumonia was recognized in the 1930s, MP was actually isolated from the sputum of a patient with “atypical” pneumonia in 1944 . Early clinical observations indicated a relatively high prevalence of MP respiratory infection in younger children, especially among school-aged children from 5 to 15 years of age . So far, there have been fewer reports of MP respiratory infection in older individuals.
Lung infection caused by MP can be diagnosed with culture of respiratory specimens and/or a fourfold rise in antibody titer to MP within 2 weeks . In our patient, the MP antibody titer rose fourfold within 9 days, along with the exacerbation of some symptoms and appearance of some new ground-glass lung infiltrates. This supported our diagnosis of MP in this patient . Since the incubation period of MP infection is often as long as 1 to 3 weeks , we speculate that MP may have already existed in our patient’s respiratory system at the time when she was infected with avian influenza A H7N9.
Although MP infections are generally mild, patients may develop severe and fulminant disease at any age . This is especially the case in patients who simultaneously suffer from another disease such as avian influenza A H7N9, as observed in our patient.
The lack of a cell wall makes MP resistant to cell wall synthesis inhibitors such as β-lactam antibiotics. Effective drugs against MP include macrolides, tetracyclines, and fluoroquinolones . Our patient was given azithromycin and moxifloxacin, and the ultimate result indicates that this therapeutic regimen was fortunately efficacious. It is generally recommended that the duration of treatment with azithromycin for community-acquired MP pneumonia is 7 to 14 days . For our patient, azithromycin administration persisted for 22 days because of her poor underlying condition and her immunocompromised status.
It is noteworthy that although no fluoroquinolone resistance has been described so far in MP clinical isolates, more and more macrolide-resistant MP have been reported in recent years [14, 15]. If the clinical manifestations do not resolve in 72 hours with macrolides administration, it is recommended to change antibiotics to tetracycline (doxycycline and minocycline) or fluoroquinolones (moxifloxacin and levofloxacin) .
In cases of confirmed influenza A H7N9, if the condition of the patient is not under initial treatment or if it even worsens with new ground-glass lung infiltrates, infection with another pathogen including MP must be suspected and sought.
We cordially appreciated the special help of Professors Juan DU, Jing YANG, Qi LIU, Zhuhong ZHA, and Chunling ZHU.
There is no funding to support the case report.
Availability of data and materials
Data sharing not applicable to this article as no datasets were generated or analyzed during the current case report.
HL and SW took the patient in charge and were responsible for the treatments of the patient and the data collection. TY, JL, LY, XP, XL, and JW took the patient in charge. FS conceived of the article, and was responsible for the manuscript. All authors have read and approved the final version of the manuscript.
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Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
The authors declare that they have no competing interests.
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