Clinical potential of diagnostic methods for the rapid diagnosis of Mycoplasma pneumoniae pneumonia in adults

Recent Trend of Antimicrobial Susceptibility among Mycoplasma pneumoniae Isolated from Japanese Children

Macrolide-resistant Mycoplasma pneumoniae (MRMP) infections have become increasingly prevalent, especially in East Asia. Whereas MRMP strains have point mutations that are implicated in conferring resistance, monitoring the antibiotic susceptibility of M. pneumoniae and identifying mutations in the resistant strains is crucial for effective disease management. Therefore, we investigated antimicrobial susceptibilities among M. pneumoniae isolates obtained from Japanese children since 2011. To establish the current susceptibility trend, we analyzed the minimum inhibitory concentrations (MICs) of M. pneumoniae in recent years (2017−2020) in comparison with past data. Our observation of 122 M. pneumoniae strains suggested that 76 were macrolide-susceptible M. pneumoniae (MSMP) and 46 were macrolide-resistant. The MIC ranges (µg/mL) of clarithromycin (CAM), azithromycin (AZM), tosufloxacin (TFLX), and minocycline (MINO) to all M. pneumoniae isolates were 0.001−>128, 0.00012−>128, 0.25−0.5, and 0.125−4 µg/mL, respectively. None of the strains was resistant to TFLX or MINO. The MIC distributions of CAM and AZM to MSMP and MINO to all M. pneumoniae isolates were significantly lower, but that of TFLX was significantly higher than that reported in all previous data concordant with the amount of recent antimicrobial use. Therefore, continuation of appropriate antimicrobial use for M. pneumoniae infection is important.

Community-Acquired Pneumonia: Postpandemic, Not Post-COVID-19

The coronavirus disease 2019 (COVID-19) pandemic upended our approach to imaging community-acquired pneumonia, and this will alter our diagnostic algorithms for years to come. In light of these changes, it is worthwhile to consider several postpandemic scenarios of community-acquired pneumonia: (1) patient with pneumonia and recent positive COVID-19 testing; (2) patient with air space opacities and history of prior COVID-19 pneumonia (weeks earlier); (3) multifocal pneumonia with negative or unknown COVID-19 status; and (4) lobar or sublobar pneumonia with negative or unknown COVID-19 status. In the setting of positive COVID-19 testing and typical radiologic findings, the diagnosis of COVID-19 pneumonia is generally secure. The diagnosis prompts vigilance for thromboembolic disease acutely and, in severely ill patients, for invasive fungal disease. Persistent or recurrent air space opacities following COVID-19 infection may more often represent organizing pneumonia than secondary infection. When COVID-19 status is unknown or negative, widespread airway-centric disease suggests infection with mycoplasma, Haemophilus influenzae, or several respiratory viruses. Necrotizing pneumonia favors infection with pneumococcus, Staphylococcus, Klebsiella, and anaerobes. Lobar or sublobar pneumonia will continue to suggest the diagnosis of pneumococcus or consideration of other pathogens in the setting of local outbreaks. A positive COVID-19 test accompanied by these imaging patterns may suggest coinfection with one of the above pathogens, or when the prevalence of COVID-19 is very low, a false positive COVID-19 test. Clinicians may still proceed with testing for COVID-19 when radiologic patterns are atypical for COVID-19, dependent on the patient's exposure history and the local epidemiology of the virus.

Mycoplasma pneumoniae among Chinese Outpatient Children with Mild Respiratory Tract Infections during the Coronavirus Disease 2019 Pandemic

Mycoplasma pneumoniae is a common pathogen causing respiratory disease in children. We sought to investigate the epidemiology of M. pneumoniae among outpatient children with mild respiratory tract infections (RTIs) during the coronavirus disease 2019 (COVID-19) pandemic. Eligible patients were prospectively enrolled from January 2020 to June 2021. Throat swabs were tested for M. pneumoniae RNA. M. pneumoniae IgM was tested by a colloidal gold assay. Macrolide resistance and the effect of the COVID-19 countermeasures on M. pneumoniae prevalence were assessed. Symptom scores, treatments, and outcomes were evaluated. Eight hundred sixty-two eligible children at 15 centers in China were enrolled. M. pneumoniae was detected in 78 (9.0%) patients. Seasonally, M. pneumoniae peaked in the first spring and dropped dramatically to extremely low levels over time until the next summer. Decreases in COVID-19 prevalence were significantly associated with decreases in M. pneumoniae prevalence (r = 0.76, P = 0.001). The macrolide resistance rate was 7.7%. The overall sensitivity and specificity of the colloidal gold assay used in determining M. pneumoniae infection were 32.1% and 77.9%, respectively. No more benefits for improving the severity of symptoms and outcomes were observed in M. pneumoniae-infected patients treated with a macrolide than in those not treated with a macrolide during follow-up. The prevalences of M. pneumoniae and macrolide resistance in outpatient children with mild RTIs were at low levels in the early stage of the COVID-19 pandemic but may have rebounded recently. The colloidal gold assay for M. pneumoniae IgM may be not appropriate for diagnosis of M. pneumoniae infection. Macrolides should be used with caution among outpatients with mild RTIs. IMPORTANCE This is the first and largest prospective, multicenter, active, population-based surveillance study of the epidemiology of Mycoplasma pneumoniae among outpatient children with mild respiratory tract infections (RTIs) during the COVID-19 pandemic. Nationwide measures like strict face mask wearing and restrictions on population movement implemented to prevent the spread of COVID-19 might also effectively prevent the spread of M. pneumoniae. The prevalence of M. pneumoniae and the proportion of drug-resistant M. pneumoniae isolates in outpatient children with mild RTIs were at low levels in the early stage of the COVID-19 pandemic but may have rebounded recently. The colloidal gold assay for M. pneumoniae IgM may be not appropriate for screening and diagnosis of M. pneumoniae infection. Macrolides should be used with caution among outpatients with mild RTIs.

The investigation of P1 gene in Mycoplasma pneumonia isolated from atypic pneumonia by molecular methods, determine IgG antibody and MIC to ciprofloxacin antibiotic

Mycoplasma pneumoniae, which causes atypical pneumonia, is a well-established pathogen of the respiratory tract. This bacterium is intrinsically susceptible to fluoroquinolones. But recently, drug-resistant forms of this bacterium have been reported. This study aims to determine the prevalence of this bacterium by ELISA and PCR and MIC to ciprofloxacin. The clinical samples (blood and nasopharyngeal swab) were collected from 100 patients, who were referred to selective hospitals in Tehran with respiratory complaints, were enrolled in 2017. Nasopharyngeal swab sample collections were cultured on PPLO broth and PPLO agar. After culturing and DNA extraction, PCR was performed by specific P1 genes primers. Ciprofloxacin's MIC of Mycoplasma pneumonia isolated was determined by the Micro-broth dilution method. The serum of IgG antibody titers was also measured by ELISA Mycoplasma pneumonia. In this study, out of 100 samples, 12 bacteria were isolated on PPLO agar. Using specific primers, 7 samples of Mycoplasma speciesism-specific were positive for the presence of M.pneumoniae and 2 Ciprofloxacin resistant isolates were evaluated. ELISA results show that IgG titer antibody is existent in 19 samples and 5 samples are intermediate as well. IgG antibody titer average in the whole sample is 27/66 U/ml, but it is in Positive samples by P1 PCR is 45/75 U/ml. This study showed that PCR is a sensitive and reliable method for rapid detection of M. pneumoniae bacteria in respiratory infectious samples, but the results of this method are different from the ELISA method. Additionally, it seems that the resistance to ciprofloxacin is relatively common among M. pneumoniae.

Identification of Coinfections by Viral and Bacterial Pathogens in COVID-19 Hospitalized Patients in Peru: Molecular Diagnosis and Clinical Characteristics

The impact of respiratory coinfections in COVID-19 is still not well understood despite the growing evidence that consider coinfections greater than expected. A total of 295 patients older than 18 years of age, hospitalized with a confirmed diagnosis of moderate/severe pneumonia due to SARS-CoV-2 infection (according to definitions established by the Ministry of Health of Peru) were enrolled during the study period. A coinfection with one or more respiratory pathogens was detected in 154 (52.2%) patients at hospital admission. The most common coinfections were Mycoplasma pneumoniae (28.1%), Chlamydia pneumoniae (8.8%) and with both bacteria (11.5%); followed by Adenovirus (1.7%), Mycoplasma pneumoniae/Adenovirus (0.7%), Chlamydia pneumoniae/Adenovirus (0.7%), RSV-B/Chlamydia pneumoniae (0.3%) and Mycoplasma pneumoniae/Chlamydia pneumoniae/Adenovirus (0.3%). Expectoration was less frequent in coinfected individuals compared to non-coinfected (5.8% vs. 12.8%). Sepsis was more frequent among coinfected patients than non-coinfected individuals (33.1% vs. 20.6%) and 41% of the patients who received macrolides empirically were PCR-positive for Mycoplasma pneumoniae and Chlamydia pneumoniae.

Atypical pneumonia: Pathophysiology, diagnosis, and treatment

Atypical pneumonia is caused by atypical pathogens that are not detectable with Gram stain and cannot be cultured using standard methods. The most common causative organisms of atypical pneumonia are Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella species. The therapeutic approach for atypical pneumonias is different than that for typical pneumonia. Typical bacterial pathogens classically respond to β-lactam antimicrobial therapy because they have a cell wall amenable to β-lactam disruption. On the contrary, most atypical pathogens do not have a bacterial cell wall, some are intracellular (e.g., Legionella), and some are paracellular (e.g., M. pneumoniae). To prevent an increase in the number of antimicrobial-resistant strains, the Japanese pneumonia guidelines have proposed a differential diagnosis for typical bacterial pneumonia and atypical pneumonia to select an appropriate antibiotic for the management of mild-to-moderate pneumonia. The guidelines have set up six parameters and criteria based on the clinical symptoms, physical signs, and laboratory data. However, in the elderly individuals and patients with underlying diseases, the differential diagnosis may be difficult or a mixed infection may be latent. Therefore, in these individuals, the administration of a β-lactam drug plus a macrolide or tetracycline, or only fluoroquinolone should be considered from the beginning to cover bacterial and atypical pneumonia.

Study of normal flora in the pharynx of healthy children

To improve our current understanding of normal flora in children, we investigated bacterial isolates from pharynx and nasopharynx of 173 and 233 healthy children, respectively. The bacterial isolation rates were compared among three age groups: infants (<1 year), toddlers (1-5 years), and school-age children (6-15 years). Gram-positive cocci (GPC) were the predominant bacteria in the pharynx (Streptococcus mitis/oralis, 87.3%; Streptococcus salivarius, 54.3%; Rothia mucilaginosa, 41.6%; Staphylococcus aureus, 39.3%). Among infants, Streptococcus salivarius and Neisseria subflava, which are related to the development of teeth, were significantly lower than in the other age groups (p<0.0001, S. salivarius; p<0.01, N. subflava). Gram-negative rods (GNR) predominated the nasopharynx (Moraxella catarrhalis, 32.1%; and Moraxella nonliquefaciens, 28.3%) except for Corynebacterium pseudodiphtheriticum (44.2%) of gram-positive rods. Among toddlers, Moraxella catarrhalis and Streptococcus pneumoniae, which are the most common pathogens in acute otitis media, were significantly higher than in the infant group (p<0.05 for both). Among bacterial species implicated in pediatric respiratory infection, Streptococcus pyogenes was isolated in 3.5% of pharyngeal samples. S. pneumoniae and Haemophilus influenzae were isolated in 22.3% and 17.2% of nasopharyngeal samples, respectively. In conclusion, normal flora of the respiratory tract differs not only by sampling site but also by age group.

Recent acute reduction in macrolide-resistant Mycoplasma pneumoniae infections among Japanese children

INTRODUCTION

Mycoplasma pneumoniae contributes to numerous pneumonia cases among children and young adults. Therefore, this study aimed to investigate the prevalence of M. pneumoniae infections among Japanese children, occurring since 2008.

METHODS

Nasopharyngeal swab specimens were obtained from all cases, following which real-time PCR was performed to identify M. pneumoniae. Further, the p1 genotypes of isolates were determined using the PCR restriction fragment length polymorphism typing method.

RESULTS

The annual rate of macrolide-resistant M. pneumoniae (MRMP) infections peaked at 81.8% in 2012 and decreased annually until 2015. Although the infection rate increased to 65.3% in 2016, it decreased again to 14.3% in 2018. Although >90% of isolates harbored the type 1 genotype until 2012, this rate decreased, and approximately 80% harbored p1 genotypes other than type 1 in 2018. Furthermore, the occurrence rate of MRMP among the type 1 isolates was very high (82.4%), whereas that among p1 genotypes other than type 1 was very low (6.5%).

CONCLUSIONS

MRMP occurrence potentially decreased owing to changes in not only antibiotic usage but also in the distribution of p1 genotype among isolates.

Current situation and need for prevention of invasive pneumococcal disease and pneumococcal pneumonia in 6- to 64-year-olds in Japan

We conducted a systematic review of the literature to evaluate the reported epidemiology and burden of invasive pneumococcal disease (IPD) and pneumococcal pneumonia (PP) among children and adults aged 6-64 years in Japan. Studies published from Japan between September 2009 and September 2019 and indexed in the MEDLINE/PubMed or ICHUSHI databases were evaluated. A majority of the studies reported overlapping age ranges, including children aged <6 years and adults aged >64 years. According to the national surveillance data, 19% of the IPD cases were patients aged 5-59 years, and an increasing trend in IPD cases was reported from 2013 to 2017. Comorbidities were consistent with those reported by the Advisory Committee on Immunization Practices. Deaths from IPD appeared to increase nearly 3-fold between 2013 and 2017. Overall, both 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) coverage was higher for IPD compared with PP. All the serotypes known to be prominent in Japan were also identified as common serotypes (3, 6A, 19A: PCV13 serotypes; 12F: outbreak serotype; 15A, 35B: drug-resistant serotypes). This systematic literature review suggests a substantial burden of IPD and PP in Japanese children and adults aged 6-64 years. The burden of comorbidities, hospitalizations, and mortality was particularly high among adults. Concerted pneumococcal vaccination strategies may help to reduce the incidence and burden of IPD and PP in this large proportion of the Japanese population.

Low prevalence of Chlamydia pneumoniae infections during the Mycoplasma pneumoniae epidemic season: Results of nationwide surveillance in Japan

OBJECTIVE

Chlamydia pneumoniae and Mycoplasma pneumoniae are both common causes of atypical pneumonia. We conducted an annual national survey of Japanese children to screen them for C. pneumoniae infections during the M. pneumoniae epidemic season.

METHODS

Nasopharyngeal swab specimens were collected from children aged 0-15 years with suspected acute lower respiratory tract infection due to atypical pathogens, at 85 medical facilities in Japan from June 2008 to March 2018. Specimens were tested for infection using real-time polymerase chain reaction assays.

RESULTS

Of 5002 specimens tested, 1822 (36.5%) were positive for M. pneumoniae alone, 42 (0.8%) were positive for C. pneumoniae alone, and 20 (0.4%) were positive for both organisms. In children with C. pneumoniae infection, the median C. pneumoniae DNA copy number was higher in those with single infections than in those with M. pneumoniae coinfection (p = 0.08); however it did not differ significantly according to whether the children had received antibiotics prior to sample collection (p = 0.34).

CONCLUSIONS

The prevalence of C. pneumoniae infection was substantially lower than that of M. pneumoniae infection during the study period. The change in prevalence of C. pneumoniae was not influenced by that of M. pneumoniae. Children with single C. pneumoniae infection are likely to have had C. pneumoniae infection, while those with coinfection are likely to have been C. pneumoniae carriers.

A Therapeutic Strategy for All Pneumonia Patients: A 3-Year Prospective Multicenter Cohort Study Using Risk Factors for Multidrug-resistant Pathogens to Select Initial Empiric Therapy

BACKGROUND

Empiric therapy of pneumonia is currently based on the site of acquisition (community or hospital), but could be chosen, based on risk factors for multidrug-resistant (MDR) pathogens, independent of site of acquisition.

METHODS

We prospectively applied a therapeutic algorithm based on MDR risks, in a multicenter cohort study of 1089 patients with 656 community-acquired pneumonia (CAP), 238 healthcare-associated pneumonia (HCAP), 140 hospital-acquired pneumonia (HAP), or 55 ventilator-associated pneumonia (VAP).

RESULTS

Approximately 83% of patients were treated according to the algorithm, with 4.3% receiving inappropriate therapy. The frequency of MDR pathogens varied, respectively, with VAP (50.9%), HAP (27.9%), HCAP (10.9%), and CAP (5.2%). Those with ≥2 MDR risks had MDR pathogens more often than those with 0-1 MDR risk (25.8% vs 5.3%, P < .001). The 30-day mortality rates were as follows: VAP (18.2%), HAP (13.6%), HCAP (6.7%), and CAP (4.7%), and were lower in patients with 0-1 MDR risks than in those with ≥2 MDR risks (4.5% vs 12.5%, P < .001). In multivariate logistic regression analysis, 5 risk factors (advanced age, hematocrit <30%, malnutrition, dehydration, and chronic liver disease), as well as hypotension and inappropriate therapy were significantly correlated with 30-day mortality, whereas the classification of pneumonia type (VAP, HAP, HCAP, CAP) was not.

CONCLUSIONS

Individual MDR risk factors can be used in a unified algorithm to guide and simplify empiric therapy for all pneumonia patients, and were more important than the classification of site of pneumonia acquisition in determining 30-day mortality.

CLINICAL TRIALS REGISTRATION

JMA-IIA00146.

Immunochromatography for the diagnosis of Mycoplasma pneumoniae infection: A systematic review and meta-analysis

The aim of this study was to evaluate the diagnostic performance of immunochromatographic tests (ICTs) for the detection of Mycoplasma pneumoniae. Medline/Pubmed, Embase, the Cochrane Library, and ISI Web of Science were searched through June 12, 2019 for relevant studies that used ICTs for the detection of M. pneumoniae infection with polymerase chain reaction (PCR) or microbial culturing as reference standards. Pooled diagnostic accuracy with 95% confidence interval (CI) was calculated using a bivariate random effects model. We also constructed summary receiver operating characteristic curves and calculated the area under the curve (AUC). Statistical heterogeneity was evaluated by χ² test or Cochrane’s Q test. Thirteen studies including 2,235 samples were included in the meta-analysis. The pooled sensitivity and specificity for diagnosing M. pneumoniae infection were 0.70 (95% CI: 0.59–0.79) and 0.92 (95% CI: 0.87–0.95), respectively. The positive likelihood ratio (LR) was 8.94 (95% CI: 4.90–14.80), negative LR 0.33 (95% CI: 0.22–0.46), diagnostic odds ratio 29.20 (95% CI: 10.70–64.20), and AUC 0.904. In subgroup analysis, ICTs demonstrated similar pooled sensitivities and specificities in populations of children only and mixed populations (children + adults). Specimens obtained from oropharyngeal swabs exhibited a higher sensitivity and specificity than those of nasopharyngeal swab. Moreover, pooled estimates of sensitivity and accuracy for studies using PCR as a reference standard were higher than those using culture. The pooled sensitivity and specificity of Ribotest Mycoplasma^®, the commercial kit most commonly used in the included studies, were 0.66 and 0.89, respectively. Overall, ICT is a rapid user-friendly method for diagnosing M. pneumoniae infection with moderate sensitivity, high specificity, and high accuracy. This suggests that ICT may be useful in the diagnostic workup of M. pneumoniae infection; however, additional studies are needed for evaluating the potential impact of ICT in clinical practice.

Significance of clinical phenomes of patients with COVID-19 infection: A learning from 3795 patients in 80 reports

A new coronavirus SARS-CoV-2 has caused outbreaks in multiple countries and the number of cases is rapidly increasing through human-to-human transmission. Clinical phenomes of patients with SARS-CoV-2 infection are critical in distinguishing it from other respiratory infections. The extent and characteristics of those phenomes varied depending on the severities of the infection, for example, beginning with fever or a mild cough, progressed with signs of pneumonia, and worsened with severe or even fatal respiratory difficulty in acute respiratory distress syndrome. We summarized clinical phenomes of 3795 patients with COVID-19 based on 80 published reports from the onset of outbreak to March 2020 to emphasize the importance and specificity of those phenomes in diagnosis and treatment of infection, and evaluate the impact on medical services. The data show that the incidence of male patients was higher than that of females and the level of C-reaction protein was increased as well as most patients' imaging included ground-glass opacity. Clinical phenomes of SARS-CoV-2 infection were compared with those of SARS-CoV and MERS-CoV infections. There is an urgent need to develop an artificial intelligence-based machine learning capacity to analyze and integrate radiomics- or imaging-based, patient-based, clinician-based, and molecular measurements-based data to fight the outbreak of COVID-19 and enable more efficient responses to unknown infections in future.

A reproducible robust likelihood approach to inference about marginal characteristics of binary data in paired settings

We introduce a robust likelihood approach to inference about marginal distributional characteristics for paired data without modeling correlation/joint probabilities. This method is reproducible in that it is applicable to paired settings with various sizes. The virtue of the new strategy is elucidated via testing marginal homogeneity in paired triplet scenario. We use simulations and real data analysis to demonstrate the merit of our robust likelihood methodology.

Macrolide-Resistant Mycoplasma pneumoniae Infection, Japan, 2008-2015

We evaluated isolates obtained from children with Mycoplasma pneumoniae infection throughout Japan during 2008–2015. The highest prevalence of macrolide-resistant M. pneumoniae was 81.6% in 2012, followed by 59.3% in 2014 and 43.6% in 2015. The prevalence of macrolide-resistant M. pneumoniae among children in Japan has decreased.

Diagnostic Imaging in Sepsis of Pulmonary Origin

Lung infections (community- or hospital-acquired) represent the most common cause for sepsis. Diagnostic imaging plays a crucial role in the initial evaluation of patients with criteria for sepsis and suspected pulmonary infection. In patients with clinical signs and symptoms of respiratory infection, the chest X-ray allows confirming the diagnosis of pneumonia. On the other hand, the chest X-ray can be useful to assess response to treatment (in some patients), define a pattern suggesting specific germs (particularly TB), identify complications (empyema and ARDS), and propose a differential diagnosis.

Mycoplasma pneumoniae from the Respiratory Tract and Beyond

Mycoplasma pneumoniae is an important cause of respiratory tract infections in children as well as adults that can range in severity from mild to life-threatening. Over the past several years there has been much new information published concerning infections caused by this organism. New molecular-based tests for M. pneumoniae detection are now commercially available in the United States, and advances in molecular typing systems have enhanced understanding of the epidemiology of infections. More strains have had their entire genome sequences published, providing additional insights into pathogenic mechanisms. Clinically significant acquired macrolide resistance has emerged worldwide and is now complicating treatment. In vitro susceptibility testing methods have been standardized, and several new drugs that may be effective against this organism are undergoing development. This review focuses on the many new developments that have occurred over the past several years that enhance our understanding of this microbe, which is among the smallest bacterial pathogens but one of great clinical importance.

A Compendium for Mycoplasma pneumoniae

Historically, atypical pneumonia was a term used to describe an unusual presentation of pneumonia. Currently, it is used to describe the multitude of symptoms juxtaposing the classic symptoms found in cases of pneumococcal pneumonia. Specifically, atypical pneumonia is a syndrome resulting from a relatively common group of pathogens including Chlamydophila sp., and Mycoplasma pneumoniae. The incidence of M. pneumoniae pneumonia in adults is less than the burden experienced by children. Transmission rates among families indicate children may act as a reservoir and maintain contagiousness over a long period of time ranging from months to years. In adults, M. pneumoniae typically produces a mild, “walking” pneumonia and is considered to be one of the causes of persistent cough in patients. M. pneumoniae has also been shown to trigger the exacerbation of other lung diseases. It has been repeatedly detected in patients with bronchitis, asthma, chronic obstructive pulmonary disorder, and cystic fibrosis. Recent advances in technology allow for the rapid diagnosis of M. pneumoniae through the use of polymerase chain reaction or rapid antigen tests. With this, more effort has been afforded to identify the causative etiologic agent in all cases of pneumonia. However, previous practices, including the overprescribing of macrolide treatment in China and Japan, have created increased incidence of macrolide-resistant M. pneumoniae. Reports from these countries indicate that >85% of M. pneumoniae pneumonia pediatric cases are macrolide-resistant. Despite its extensively studied past, the smallest bacterial species still inspires some of the largest questions. The developments in microbiology, diagnostic features and techniques, epidemiology, treatment and vaccines, and upper respiratory conditions associated with M. pneumoniae in adult populations are included within this review.

Clinical Application of High-Resolution Computed Tomographic Imaging Features of Community-Acquired Pneumonia

Background

This article discusses the value of high-resolution computed tomography (HRCT) in the diagnosis and treatment of pulmonary infections. Lung infection caused by pathogens is an important cause of death. Traditional methods to treat lung infection involved empirical antibiotic therapy. Thin-slice CT scanning is widely used in the clinical setting, and HRCT scan can very clearly show alveolar and bronchiolar involvement of infection.

Material/Methods

In total, 178 patients with community-acquired pneumonia (CAP) were enrolled. All the patients underwent CT scan, qualified sputum, and blood samples for culture or immunological biochemical tests. CT imaging features, pathogenic bacteria, and treatment results were used for statistical analysis.

Results

In 77 patients with lobar consolidation, the rate of detection was 43.26% (77/178), and in 101 patients with lobular pneumonia it was 56.74% (101/178). In 51 patients, pathogenic bacteria were detected (28.65%, 51/178). Sixteen of 33 patients detected with bacteria had cavities (48.5%, 16/33) and 35 of 145 patients detected with bacteria had no cavities (24.1%, 35/145). The difference between the 2 groups was statistically significant (χ²=7.795, P=0.005). According to the pathogenic bacteria, 38 patients were cured (74.51%, 38/51), and according to the CT imaging features 81 patients were cured (71.05%, 81/114). No statistically significant difference was found between them (χ²=0.209, P=0.647).

Conclusions

Treatment effect of CAP based on HRCT findings is not inferior to treatment effect guided by microbial characterization.

Imaging infection

Thoracic imaging is widely used to detect lower respiratory tract infections, identify their complications, and aid in differentiating infectious from noninfectious thoracic disease. Less commonly, the combination of imaging findings and a clinical setting can favor infection with a specific organism. This confluence can occur in cases of bronchiectatic nontuberculous mycobacterial infections in immune-competent hosts, invasive fungal disease among neutropenic patients, Pneumocystis jiroveci pneumonia in patients with AIDS, and in cytomegalovirus infections in patients with recent hematopoietic cell transplantation. These specific diagnoses often depend on computed tomography scanning rather than chest radiography alone.

Detection failure rate of chest radiography for the identification of nursing and healthcare-associated pneumonia

AIM

To clarify the detection failure rate of chest radiography for the identification of nursing and healthcare-associated pneumonia (NHCAP), we compared high-resolution computed tomography (HRCT) with chest radiography simultaneously for patients with clinical symptoms and signs leading to a suspicion of NHCAP.

METHODS

We analyzed 208 NHCAP cases and compared them based on four groups defined using NHCAP criteria, patients who were: Group A) resident in an extended care facility or nursing home; Group B) discharged from a hospital within the preceding 90 days; Group C) receiving nursing care and had poor performance status; and Group D) receiving regular endovascular treatment.

RESULTS

Chest radiography was inferior to HRCT for the identification of pneumonia (149 vs 208 cases, p < 0.0001). Among the designated NHCAP criteria, chest radiography identified pneumonia cases at a significantly lower frequency than HRCT in Group A (70 vs 97 cases, p = 0.0190) and Group C (86 vs 136 cases, p < 0.0001). The detection failure rate of chest radiography differed among NHCAP criteria; 27.8% in Group A, 26.5% in Group B, 36.7% in Group C and 5.8% in Group D. Cerebrovascular disease and poor functional status were significantly more frequent in patients in Groups A and C compared with those in Groups B and D.

CONCLUSIONS

Physicians may underestimate pneumonia shadow in chest radiographs in patients with NHCAP, and the detection failure rate of chest radiography differed among NHCAP criteria. Poor functional status may correlate with the low accuracy of chest radiography in diagnosing pneumonia.

Diagnostic sensitivity of a rapid antigen test for the detection of Mycoplasma pneumoniae: Comparison with real-time PCR

A rapid antigen kit for the detection of the Mycoplasma pneumoniae ribosomal protein L7/L12 using an immunochromatographic assay, Ribotest Mycoplasma, became available in Japan in 2013. To determine the sensitivity of Ribotest compared with real-time polymerase chain reaction (PCR), we prospectively performed these two tests simultaneously in adolescent and adult patients with community-acquired pneumonia (CAP). In addition, we retrospectively analyzed the theoretical sensitivity of Ribotest using M. pneumoniae PCR-positive specimens from previous studies. In prospective study, 118 CAP cases were enrolled, and 16 cases were diagnosed as M. pneumoniae pneumonia; eight cases were PCR-positive, one case was culture positive, and all cases demonstrated a four-fold increase in antibody titer. Ribotest was positive in 15 cases; five cases were PCR positive and 10 cases were PCR negative. For the PCR was control test, the sensitivity, specificity, and overall agreement with Ribotest were 62.5%, 90.9%, and 88.9%, respectively. In the retrospective study, we used 1110 M. pneumoniae PCR-positive specimens, which are collected from pediatric patients with respiratory tract infection who visited 65 institutions throughout Japan. Using a cut-off level for the Ribotest of 8.3 × 10(4) copy/mL in transport medium, 667 (60.0%) specimens were theoretically positive. In conclusion, our prospective and retrospective results demonstrated that the diagnostic sensitivity of Ribotest compared with PCR was not high, at approximately 60%. Thus, treatment decisions about M. pneumoniae pneumonia should be based on clinical findings such as Japanese Respiratory Society scoring system and not on Ribotest results alone.

Setting a standard for the initiation of steroid therapy in refractory or severe Mycoplasma pneumoniae pneumonia in adolescents and adults

Serum interleukin (IL)-18 level was thought to be a useful as a predictor of refractory or severe Mycoplasma pneumoniae pneumonia, and steroid administration is reported to be effective in this situation. The serum levels of IL-18 correlated significantly with those of lactate dehydrogenase (LDH). The purpose of this study was to set a standard for the initiation of steroid therapy in M. pneumoniae pneumonia using a simple serum marker. We analyzed 41 adolescent and adult patients with refractory or severe M. pneumoniae pneumonia who received steroid therapy, and compared them with 108 patients with M. pneumoniae pneumonia who responded to treatment promptly (control group). Serum LDH levels were significantly higher in the refractory and severe group than in the control group at the initiation of steroid therapy (723 vs 210 IU/L, respectively; p < 0.0001). From receiver operating characteristic curve analysis, we calculated serum LDH cut-off levels of 364 IU/L at initiation of steroid therapy and 302 IU/L at 1-3 days before the initiation of steroid therapy. The administration of steroids to patients in the refractory and severe group resulted in the rapid improvement of symptoms and a decrease in serum LDH levels in all patients. Serum LDH level can be used as a useful parameter to determine the initiation of steroid therapy in refractory or severe M. pneumoniae pneumonia. A serum LDH level of 302-364 IU/L seems to be an appropriate criterion for the initiation of steroid therapy.

Macrolide-resistant Mycoplasma pneumoniae pneumonia in adolescents and adults: clinical findings, drug susceptibility, and therapeutic efficacy

We investigated differences in the clinical findings between 30 patients with macrolide-resistant Mycoplasma pneumoniae pneumonia and 43 patients with macrolide-sensitive M. pneumoniae pneumonia in adolescents and adults. No differences in clinical presentation were observed between the two groups. Among patients with macrolide-resistant Mycoplasma pneumoniae pneumonia, treatment was more effective in the groups that received quinolones and minocycline than in the group that received macrolides (P = 0.0361 and P = 0.0237, respectively).

A new strategy for healthcare-associated pneumonia: a 2-year prospective multicenter cohort study using risk factors for multidrug-resistant pathogens to select initial empiric therapy

BACKGROUND

Optimal empiric therapy for hospitalized patients with healthcare-associated pneumonia (HCAP) is uncertain.

METHODS

We prospectively applied a therapeutic algorithm, based on the presence of risk factors for multidrug-resistant (MDR) pathogens in a multicenter cohort study of 445 pneumonia patients, including both community-acquired pneumonia (CAP; n = 124) and HCAP (n = 321).

RESULTS

MDR pathogens were more common (15.3% vs 0.8%, P < .001) in HCAP patients than in CAP patients, including Staphylococcus aureus (11.5% vs 0.8%, P < .001); methicillin-resistant S. aureus (6.9% vs 0%, P = .003); Enterobacteriaceae (7.8% vs 2.4%, P = .037); and Pseudomonas aeruginosa (6.9% vs 0.8%, P = .01). Using the proposed algorithm, HCAP patients with ≥2 MDR risk factors, one of which was severity of illness (n = 170), vs HCAP patients with 0-1 risk factor (n = 151) had a significantly higher frequency of MDR pathogens (27.1% vs 2%, P < .001). In total, 93.1% of HCAP patients were treated according to the therapy algorithm, with only 53% receiving broad-spectrum empiric therapy, yet 92.9% received appropriate therapy for the identified pathogen. Thirty-day mortality was significantly higher for HCAP than for CAP (13.7% vs 5.6%, P = .017), but among HCAP patients with 0-1 MDR risk factor, mortality was lower than with ≥2 MDR risk factors (8.6% vs 18.2%, P = .012). In multivariate analysis, initial treatment failure, but not inappropriate empiric antibiotic therapy, was a mortality risk factor (odds ratio, 72.0).

CONCLUSIONS

Basing empiric HCAP therapy on its severity and the presence of risk factors for MDR pathogens is a potentially useful approach that achieves good outcomes without excessive use of broad-spectrum antibiotic therapy.

CLINICAL TRIALS REGISTRATION

Japan Medical Association Center for Clinical Trials, JMA-IIA00054.

Nationwide surveillance of macrolide-resistant Mycoplasma pneumoniae infection in pediatric patients

We conducted nationwide surveillance to investigate regional differences in macrolide-resistant (MR) Mycoplasma pneumoniae strains in Japan. The prevalence of MR M. pneumoniae in pediatric patients gradually increased between 2008 and 2012. Although regional differences were observed, high levels of MR genes were detected in all seven surveillance areas throughout Japan and ranged in prevalence from 50% to 93%. These regional differences were closely related to the previous administration of macrolides.

Therapeutic efficacy of macrolides, minocycline, and tosufloxacin against macrolide-resistant Mycoplasma pneumoniae pneumonia in pediatric patients

The importance of macrolide-resistant (MR) Mycoplasma pneumoniae has become much more apparent in the past decade. We investigated differences in the therapeutic efficacies of macrolides, minocycline, and tosufloxacin against MR M. pneumoniae. A total of 188 children with M. pneumoniae pneumonia confirmed by culture and PCR were analyzed. Of these, 150 patients had a strain with an MR gene and 134 had one with an A-to-G mutation at position 2063 of M. pneumoniae 23S rRNA domain V. Azithromycin (n = 27), clarithromycin (n = 23), tosufloxacin (n = 62), or minocycline (n = 38) was used for definitive treatment of patients with MR M. pneumoniae. Defervescence within 48 h after the initiation of antibiotic therapy was observed in 41% of the patients in the azithromycin group, 48% of those in the clarithromycin group, 69% of those in the tosufloxacin group, and 87% of those in the minocycline group. The average number of days of fever after the administration of antibiotic treatment was lower in the minocycline and tosufloxacin groups than in the macrolide groups. The decrease in the M. pneumoniae burden, as estimated by the number of DNA copies, after 48 to 96 h of treatment was more rapid in patients receiving minocycline (P = 0.016) than in those receiving tosufloxacin (P = 0.049), azithromycin (P = 0.273), or clarithromycin (P = 0.107). We found that the clinical and bacteriological efficacies of macrolides against MR M. pneumoniae pneumonia was low. Our results indicated that minocycline rather than tosufloxacin can be considered the first-choice drug for the treatment of M. pneumoniae pneumonia in children aged ≥ 8 years.

Diagnostic value of symptoms and laboratory data for pertussis in adolescent and adult patients

Background

Several symptoms are classically thought to be suggestive of pertussis in children, but the diagnostic value of these symptoms in adolescent and adult patients is unclear. We evaluated the accuracy of the clinical findings for the early presumptive diagnosis of pertussis in adolescent and adult patients. Furthermore, we measured fractional exhaled nitric oxide (FeNO) with regard to whether we could distinguish eosinophilic inflammation of the airway and pertussis. FeNO is not expected to be associated with pertussis.

Methods

We compared 183 cases with laboratory-confirmed pertussis using serology and polymerase chain reaction and 1,132 cases without laboratory-confirmed pertussis.

Results

Among pertussis patients, paroxysmal cough was common with 90% sensitivity, but the specificity was low (25%). Posttussive vomiting and whoop were less common (sensitivity 25% and 19%, respectively), but both showed greater specificity for pertussis (80% and 86%, respectively). Posttussive gagging was observed with intermediate frequency and provided greater specificity (49% and 77%, respectively). Pertussis cases were most frequent between May and August with a peak in June. The mean FeNO value for the pertussis patients was 18.2 ± 9.2 ppb, which was significantly lower than that in asthma patients (56.9 ± 20.3 ppb, p <0.001). The most useful definition was posttussive vomiting and/or gagging, and a plus normal FeNO value, which had a sensitivity of 72% and a specificity of 70%.

Conclusions

Clinical symptoms and laboratory data are of limited value in making the diagnosis of pertussis, and it was clinically difficult to differentiate adolescent and adult patients with or without pertussis. However, pertussis should be considered if patients have posttussive vomiting and/or gagging and a normal FeNO concentration.

Atelectasis caused by macrolide-resistant Mycoplasma pneumoniae pneumonia in an adult patient

A 27-year-old, previously healthy woman was admitted to our hospital for mild pneumonia. After 2 days ceftriaxone sodium administration, her chest radiograph revealed a rightward mediastinal shift caused by atelectasis of the upper portion of the right lung. Bronchoscopic examination showed swelling in the right upper lobe bronchus and obstruction in the B1 segmental bronchus caused by complete edematous swelling. Histopathology showed acute cellular bronchitis with edema of the bronchial wall containing lymphocytes, plasma cells, and macrophages. Mycoplasma pneumoniae was detected by culture and a polymerase chain reaction test using sputum collected during bronchoscopy, and treatment was changed to minocycline. After 7 days antibiotic therapy, her condition improved and no relapse was observed. Identification of point mutations in domain V of the 23S rRNA for macrolide-resistant M. pneumoniae was performed, and an A-to-G transition at position 2063 in domain V of the 23S rRNA gene was identified. Atelectasis caused by M. pneumoniae is thought to be a common associated finding in pediatric patients, but it is rare in adults. In addition, our patient showed extremely unusual findings with obstruction caused by complete edematous swelling.

Influence of age on the clinical differentiation of atypical pneumonia in adults

BACKGROUND AND OBJECTIVE

The Japanese Respiratory Society (JRS) scoring system is a useful tool for the early and simple presumptive diagnosis of atypical pneumonia (Mycoplasma pneumoniae and Chlamydia pneumoniae pneumonia). However, it has been suggested that it is difficult to diagnose atypical pneumonia in the elderly using this system. In the present study, we evaluated the accuracy and usefulness of the JRS scoring system for diagnosing atypical pneumonia in different age groups.

METHODS

Cases of M. pneumoniae (n = 262), C. pneumoniae (n = 98) and common bacterial pneumonia (n = 364) were analysed.

RESULTS

For both atypical pneumonias, the frequency of comorbid illnesses and being in a higher risk category were significantly greater in elderly (age ≥60 years) than in non-elderly patients (age <60 years). One or more additional aetiological factors were more frequently present in elderly than in non-elderly patients. The diagnostic sensitivity and specificity for atypical pneumonia were 39% and 88%, respectively, in the elderly group, and 86% and 88%, respectively, in the non-elderly group. When the patients were stratified into 10-year age groups, the diagnostic sensitivity was highest in the 18- to 29-year age group and decreased from the youngest to the oldest age group.

CONCLUSIONS

These results indicate that it is difficult to distinguish between atypical pneumonia and bacterial pneumonia in the elderly using the JRS scoring system. When treating patients aged ≥60 years, physicians should use fluoroquinolones or β-lactam antibiotics + macrolides as empirical first-choice drugs so as to always provide antibiotic protection against potential atypical pathogens.

Chlamydophila pneumoniae serology: cross-reaction with Mycoplasma pneumoniae infection

Atypical pathogens Mycoplasma pneumoniae and Chlamydophila pneumoniae play an important role in community-acquired pneumonia. However, it has been pointed out that positive enzyme-linked immunosorbent assay (ELISA, Hitazyme C. pneumoniae) IgM reactivity is frequent among M. pneumoniae pneumonia patients. To clarify the reactivity of ELISA IgM in M. pneumoniae pneumonia, findings were compared with immunoblotting, ELNAS Plate C. pneumoniae (ELNAS) and the micro-immunofluorescence (MIF) test. Ninety-eight serologically confirmed cases with M. pneumoniae pneumonia and 10 cases with C. pneumoniae pneumonia were enrolled in this study. C. pneumoniae IgM-positive cases measured by the ELISA were observed in 30 (30 %) patients with M. pneumoniae pneumonia. However, there were no positive cases by immunoblotting, ELNAS, or MIF test. These cases determined to be IgM positive only in the ELISA were all negative by another serological test, recombinant enzyme immunoassay (rEIA), and these positive results in the ELISA were considered to be false-positive reactions. In contrast, IgM-positive findings in patients with C. pneumoniae pneumonia did not show any positive reaction in M. pneumoniae antibody titer. ELISA showed a high frequency of false-positive findings in patients with M. pneumoniae pneumonia, which included false-positive cases with a high titer for IgM. To accurately diagnose C. pneumoniae infection in various studies, including respiratory infections, researchers should consider the IgM false-positive reaction with ELISA in patients with suspected atypical pneumonia.

Clinical efficacy of macrolide antibiotics against genetically determined macrolide-resistant Mycoplasma pneumoniae pneumonia in paediatric patients

BACKGROUND AND OBJECTIVE

Since 2000, the prevalence of macrolide-resistant (MR) Mycoplasma pneumoniae has increased among paediatric patients in Japan. To determine the efficacy of macrolides against MR M. pneumoniae pneumonia, microbiological and clinical efficacies were compared during the antibiotic treatment.

METHODS

Samples from a total of 30 children with M. pneumoniae pneumonia, as confirmed by PCR and serology, were analyzed. Primers for domain V of 23S rRNA were used, and DNA sequences of the PCR products were compared with the sequence of an M. pneumoniae reference strain.

RESULTS

Isolates from 21 patients demonstrated point mutations, and these patients were defined as MR. The remaining nine patients, whose isolates showed no point mutations, were categorized as control (macrolide-sensitive) patients. The number of M. pneumoniae in nasopharyngeal samples from the control group decreased rapidly 48 h after initiation of macrolide treatment and showed a close relationship with clinical outcome. In contrast, the number of M. pneumoniae 48 h after initiation of macrolide treatment were significantly higher in samples from MR patients than in samples from macrolide-sensitive patients. In 15 of 21 MR patients, fever persisted for more than 48 h after the initiation of macrolide treatment. When treatment was changed to minocycline, fever disappeared within 48 h in all these MR patients. There were no differences between MR patients who demonstrated a reduction in fever and those in whom fever persisted after 48 h of macrolide treatment.

CONCLUSIONS

The microbiological and clinical efficacies of macrolides for treating patients with MR M. pneumoniae pneumonia were low. These results show that macrolides are clearly less effective in patients with MR M. pneumoniae pneumonia.

Macrolide-resistant Mycoplasma pneumoniae in adolescents with community-acquired pneumonia

BACKGROUND

Although the prevalence of macrolide-resistant Mycoplasma pneumoniae isolates in Japanese pediatric patients has increased rapidly, there have been no reports concerning macrolide-resistant M. pneumoniae infection in adolescents aged 16 to 19 years old. The purpose of this study was to clarify the prevalence and clinical characteristics of macrolide-resistant M. pneumoniae in adolescent patients with community-acquired pneumonia.

METHODS

A total of 99 cases with M. pneumoniae pneumonia confirmed by polymerase chain reaction (PCR) and culture were analyzed. Forty-five cases were pediatric patients less than 16 years old, 26 cases were 16 to 19-year-old adolescent patients and 28 cases were adult patients. Primers for domain V of 23S rRNA were used and DNA sequences of the PCR products were compared with the sequence of an M. pneumoniae reference strain.

RESULTS

Thirty of 45 pediatric patients (66%), 12 of 26 adolescent patients (46%) and seven of 28 adult patients (25%) with M. pneumoniae pneumonia were found to be infected with macrolide-resistant M. pneumoniae (MR patients). Although the prevalence of resistant strains was similar in pediatric patients between 2008 and 2011, an increase in the prevalence of resistant strains was observed in adolescent patients. Among 30 pediatric MR patients, 26 had an A-to-G transition at position 2063 (A2063G) and four had an A-to-G transition at position 2064 (A2064G). In 12 adolescent MR patients, 10 showed an A2063G transition and two showed an A2064G transition, and in seven adult MR patients, six showed an A2063G transition and one showed an A2064G transition.

CONCLUSIONS

The prevalence of macrolide-resistant M. pneumoniae is high among adolescent patients as well as pediatric patients less than 16-years old. To prevent outbreaks of M. pneumoniae infection, especially macrolide-resistant M. pneumoniae, in closed populations including among families, in schools and in university students, physicians should pay close attention to macrolide-resistant M. pneumoniae.

Evaluation of serological tests for diagnosis of Bordetella pertussis infection in adolescents and adults

BACKGROUND AND OBJECTIVE

Bacterial agglutination antibodies against Bordetella pertussis, Yamaguchi and Tohama strains, are frequently measured for serodiagnosis of pertussis infection in Japan. To determine the serological criteria, the comparative titres of bacterial agglutination antibody and anti-pertussis toxin (PT) antibody were evaluated.

METHODS

Antibody titres were analysed in 36 definitive (fourfold increase in agglutination antibody) and 137 presumptive (high titre of single-antibody) cases of B. pertussis infection among adolescents and adults, and in a control group of 318 healthy volunteers.

RESULTS

When a single Yamaguchi agglutinin titre of ≥ 1:1280 (> three SD above the geometric mean for the control group) was taken as diagnostic, the sensitivity and specificity at 4-5 weeks after onset of cough were 58% and 98%, respectively. Using this criterion, the clinical findings in presumptive cases were almost identical to those in definitive cases. When the two tests were compared using 318 control sera, there was no association between the Tohama agglutinin titre and the anti-PT antibody titre, whereas a weak association between the Yamaguchi agglutinin titre and the anti-PT antibody titre was observed. When the numbers of pertussis cases with high antibody titres in the two tests were compared, 60% of cases with a Yamaguchi agglutinin titre of ≥1:1280 showed an anti-PT antibody titre of ≥100 EU/mL.

CONCLUSIONS

These results indicate that the bacterial agglutination test is a method with low sensitivity and specificity for the diagnosis of B. pertussis infection. Therefore, to yield an accurate diagnosis, anti-PT antibody levels should be measured instead of bacterial agglutination antibody.

Clinical features and the role of atypical pathogens in nursing and healthcare-associated pneumonia (NHCAP): differences between a teaching university hospital and a community hospital

OBJECTIVE

The Japan Respiratory Society documented a new category of guidelines for nursing and healthcare-associated pneumonia (NHCAP), which is distinct from community acquired pneumonia (CAP). The objective of this study was to determine the epidemiological differences between NHCAP patients in a teaching university hospital and a community hospital. In addition, to clarify the strategy for treatment of NHCAP, we investigated the role of atypical pathogens.

METHODS

We analyzed 250 NHCAP and 421 CAP cases in a university hospital and 349 NHCAP and 374 CAP cases in a community hospital.

RESULTS

Patient age and the incidences of poor general condition were significantly higher in the community hospital compared with those in the university hospital. The distribution and frequency of pathogens, especially multidrug-resistant (MDR) pathogens, were significantly different between the two hospitals. Central nervous system disorders, dementia and poor performance status, which was possibility related to aspiration pneumonia, were significantly more frequent in patients with NHCAP compared with those with CAP in both hospitals. Atypical pathogens were detected in a few cases in patients with NHCAP.

CONCLUSION

There were many differences in the clinical characteristics between NHCAP patients in a university hospital and a community hospital even for hospitals located in the same area. Aspiration pneumonia was thought to be the main characteristic of NHCAP in both hospitals. Thus, all NHCAP patients did not need the same empiric therapy with a multidrug regimen directed against MDR pathogens. In addition, physicians rarely need to consider atypical pathogens in NHCAP treatment.

Outbreak of pertussis in a university laboratory

OBJECTIVE

Analysis of an outbreak of Bordetella pertussis infection in a university laboratory. To prevent and control the outbreak, we conducted a survey of the laboratory staff and their family members, and we investigated the clinical features of adult pertussis.

PATIENTS AND METHODS

During the outbreak, four out of the 10 laboratory staff and five out of 16 family members had a primary complaint of cough. Seven of nine patients were diagnosed as definitive B. pertussis infection using serology and PCR.

RESULTS

Clinical findings and laboratory data in adult patients with B. pertussis infection demonstrated non-specific cough and normal WBC and lymphocyte count. The patients who received clarithromycin prior to 14 days after clinical onset demonstrated a shorter duration of cough symptoms than patients who received clarithromycin at 14 days or more after clinical onset (duration of cough after administration of clarithromycin: 17.8 ± 6.48 days versus 35.3 ± 5.38 days; duration of total cough after clinical onset: 24.8 ± 6.65 days versus 56.8 ± 6.50 days).

CONCLUSION

The clinical findings of adult pertussis are different from pertussis in children. The efficacy of macrolide therapy clearly differed between the catarrhal phase and paroxysmal phase. Physicians should consider B. pertussis in the differential diagnosis of an outbreak of non-specific respiratory infection even in adult populations.