Macrolide-resistant Mycoplasma pneumoniae prevalence and clinical aspects in adult patients with community-acquired pneumonia in China: a prospective multicenter surveillance study.

BACKGROUND: Drug resistant Mycoplasma pneumoniae (MP) is a rising issue in the management of community-acquired pneumonia (CAP). Epidemiological monitoring is essential for identifying resistant patterns of MP isolates against various antibiotics in adult CAP patients. METHODS: This is a prospectively designed multicenter study conducted on adult patients with CAP visiting six teaching hospitals in the cities of Beijing, Shanghai and Guangzhou between September 2010 and June 2012. RESULTS: A total of 520 adult patients (mean age: 45.7±26.2 years) with CAP visiting teaching hospitals in the cities of Beijing, Shanghai and Guangzhou were included. Of the 520 patients, only 75 (14.42%) were confirmed MP positive by means of culture and real-time PCR methods. Quinolones were the most common initially prescribed antimicrobial, followed by ß-lactams and ß-lactams plus quinolones. Macrolide resistance was as high as 80% and 72% against erythromycin (ERY) and azithromycin (AZM) respectively, which were associated with the A2063G transition mutation in domain V of the 23S ribosomal RNA (rRNA) gene. Six strains with mild to moderate ERY-resistant level were still susceptible to AZM. Tetracycline (TET), minocycline (MIN) and quinolones [moxifloxacin (MOX) and fluoroquinolones] had no signs of resistance. CONCLUSIONS: High resistance was observed with macrolides, whereas, none of the MP strains were resistant to fluoroquinolones and TET. Hence, macrolide resistant MP (MRMP)_infections could be well treated with fluoroquinolones. However, few isolated strains had minimal inhibitory concentration (MIC) values on the edge of resistance to quinolones, alarming a quinolone-resistant MP in the near future.

Overview of antimicrobial options for Mycoplasma pneumoniae pneumonia: focus on macrolide resistance.

BACKGROUND AND AIMS: Community-acquired pneumonia (CAP) is a common infectious disease affecting children and adults of any age. Mycoplasma pneumoniae has emerged as leading causative agent of CAP in some region, and the abrupt increasing resistance to macrolide that widely used for management of M. pneumoniae has reached to the level that it often leads to treatment failures. OBJECTIVE: We aim to discuss the drivers for development of macrolide-resistant M. pneumoniae, antimicrobial stewardship and also the potential treatment options for patients infected with macrolide-resistant M. pneumonia. METHODS: The articles in English and Chinese published in Pubmed and in Asian medical journals were selected for the review. RESULTS: M. pneumoniae can develop macrolide resistance by point mutations in the 23S rRNA gene. Inappropriate and overuse of macrolides for respiratory tract infections may induce the resistance rapidly. A number of countries have introduced the stewardship program for restricting the use of macrolide. Tetracyclines and fluoroquinolones are highly effective for macrolide-resistant strains, which may be the substitute in the region of high prevalence of macrolide-resistant M. pneumoniae. CONCLUSION: The problem of macrolide resistant M. pneumonia is emerging. Antibiotic stewardship is needed to inhibit the inappropriate use of macrolide and new antibiotics with a more acceptable safety profile for all ages need to be explored.

[Survey of macrolide resistance in Mycoplasma pneumoniae in adult patients with community-acquired pneumonia in Beijing, China].

OBJECTIVE: To explore the tendency of macrolide resistance in Mycoplasma pneumoniae infection in community-acquired pneumonia (CAP) patients in Beijing. METHODS: Adult CAP patients of ≥ 18 yrs were enrolled in 3 medical centers in Beijing , China. Throat swab samples were taken from all the patients to perform the culture of M. pneumoniae . All the isolated M. pneumoniae strains were subjected to susceptibility evaluation for 6 agents, including macrolides such as erythromycin and azithromycin. In strains showing macrolide resistance, the 23S rRNA gene was analyzed. RESULTS: A total 53 strains of M. pneumoniae were isolated from 321 enrolled patients. Thirty-eight of the isolated strains (71.7%) were resistant to erythromycin and 32 of them (60.4%) were resistant to azithromycin. Six strains with moderate or low level of erythromycin-resistance were still susceptible to azithromycin. No fluoroquinolone-resistant or tetracycline-resistant strains were observed in our study. Point transition of A2063G in the 23S ribosomal RNA gene was the main reason for the high prevalence of macrolide resistance. CONCLUSIONS: The prevalence of macrolide resistance in M. pneumoniae is very high in adult CAP patients in Beijing. Studies are needed to clarify the clinical meaning of prevalence of macrolide-resistant M. pneumoniae in adults CAP patients.

Evaluation of the Japanese Respiratory Society guidelines for the identification of Mycoplasma pneumoniae pneumonia.

BACKGROUND AND OBJECTIVE: Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality worldwide. Mycoplasma pneumoniae is one of the major causative pathogens of CAP. Early diagnosis of M. pneumoniae pneumonia is crucial for initiating appropriate antibiotic therapy. The aim of this study was to determine whether the Japanese Respiratory Society (JRS) guidelines on CAP are effective for diagnosing M. pneumoniae pneumonia. METHODS: Between August 2008 and July 2009, adult outpatients with CAP were consecutively enrolled. The aetiology of CAP was determined by culture and real-time polymerase chain reaction (PCR) methods to detect M. pneumoniae, urine antigen tests to detect Streptococcus pneumoniae and Legionella pneumoniae, blood and sputum culture for bacteria and real-time PCR for eight common respiratory viruses. The predictive value of the JRS guidelines for differentiating M. pneumoniae pneumonia from typical bacterial and viral pneumonias was determined. RESULTS: Data from 215 adult CAP outpatients was analyzed. An aetiological diagnosis was made for 105 patients (48.8%), including 62 patients with M. pneumoniae pneumonia, 17 patients with typical bacterial pneumonia and 23 patients with viral pneumonia. According to the JRS criteria for differential diagnosis of atypical pneumonia, 55 of 62 patients were correctly diagnosed with M. pneumoniae pneumonia (sensitivity 88.7%), and 31 of 40 patients with bacterial and viral pneumonia were correctly excluded (specificity 77.5%). CONCLUSIONS: The JRS guidelines on CAP provide a useful tool for the identification of M. pneumoniae pneumonia cases and differentiating these from cases of typical bacterial or viral pneumonia.

Evaluation of a new real-time PCR assay for detection of Mycoplasma pneumoniae in clinical specimens.

OBJECTIVE: To establish and evaluate a real-time PCR assay to detect Mycoplasma pneumoniae (M.pneumoniae) in clinical specimens. METHODS: By analysing the whole p1 gene sequence of 60 M.pneumoniae clinical isolates in Beijing of China, an optimized real-time PCR assay (MpP1) using p1 gene conserved region was designed. The specificity and sensitivity of this assay were evaluated and compared with other two reported assays (RepMp1 and Mp181) using 40 positive and 100 negative clinical specimens. RESULTS: The detection limit of the new assay was 8.1 fg (about 1∼3CFU) M.pneumoniae DNA. The sensitivity of MpP1, RepMp1, and Mp181 assays appeared to be 100%, 100%, and 85%, respectively. CONCLUSION: MpP1 assay is suitable for the detection of M.pneumoniae in Chinese clinical specimens.

Clinical features of pneumonia caused by 2009 influenza A(H1N1) virus in Beijing, China.

BACKGROUND: Data on symptoms and radiographic changes in patients with pandemic 2009 influenza A(H1N1) (A[H1N1]) pneumonia during convalescence have not been reported. METHODS: During October 26, 2009, and January 23, 2010, adult patients with pneumonia with laboratory-confirmed or clinically suspected A(H1N1) infections were observed for clinical characteristics, high-resolution chest CT scan, and lung function test changes during acute and 3-month convalescent phases. RESULTS: Of the 65 case subjects, the median age was 41 (interquartile range [IQR], 28-57) years, 60.0% were men, and 55.4% had at least one underlying medical condition. Sixty-two patients started oseltamivir therapy within a median of 5 (IQR, 4-6) days from the onset of illness, and 31 received IV corticosteroids. ARDS developed in 33 patients, and 24 were treated initially with noninvasive positive pressure ventilation (NPPV). In this group, NPPV was successful in 13 patients (54.2%). Nine patients died at a median of 16 (IQR, 10-24) days after onset of illness. Multivariate Cox regression identified two independent risk factors for death: progressive dyspnea after resolution of fever (relative risk, 5.852; 95% CI, 1.395-24.541; P = .016) and a higher APACHE (Acute Physiology and Chronic Health Evaluation) II score on presentation (relative risk for each point, 1.312; 95% CI, 1.140-1.511; P < .001). At 3-month follow-up of survivors with A(H1N1), ground-glass opacities were still present, although diminished, in 85.7%, and diffusing capacity for carbon monoxide was mildly reduced in 61.5%. CONCLUSIONS: Ground-glass opacities and decreased diffusing capacity were the main abnormalities observed at 3-month follow-up of survivors of A(H1N1).

High prevalence of macrolide resistance in Mycoplasma pneumoniae isolates from adult and adolescent patients with respiratory tract infection in China.

The resistance rate of 67 Mycoplasma pneumoniae isolates from 356 ambulatory adult patients with respiratory tract infection was 69% (46 of 67). All 46 macrolide-resistant strains harbored point mutations in the 23S ribosomal RNA gene. Patients infected with macrolide-resistant M. pneumoniae required significantly longer durations of antibiotic therapy and had longer time to resolution of fever.

Decreased plasma soluble thrombomodulin levels as a risk factor for pulmonary thromboembolism.

OBJECTIVE: To observe the changes of the plasma soluble thrombomodulin (sTM) concentrations in patients with pulmonary thromboembolism (PTE) and assess the association between plasma sTM concentration and the risk of PTE. PATIENTS AND METHODS: We measured plasma concentrations of sTM, protein C (PC) and protein S (PS) and examined the association between those plasma markers and the risk of PTE in 72 selected PTE patients and 70 controls. RESULTS: Significant difference was identified in plasma sTM level between overall PTE patients and controls. Female PTE patients had statistically lower sTM concentrations than male patients. A positive linear correlation was found between plasma sTM concentration and age in female patients. Decreased plasma sTM concentration was associated with a continuously and progressively increased risk for PTE in women. The concentrations of plasma PC and PS did not differ between groups and no significant quantitative association was identified between the risk of PTE and the levels of plasma PC or PS. CONCLUSION: Decreased plasma sTM concentration is associated with an increased risk of PTE in women.