Mycoplasma pneumoniae pneumonia: CT features in 16 patients

Clinical and prognostic relevance of Mycoplasma felis PCR detection in feline lower respiratory tract disease

OBJECTIVES

The aim of this retrospective cohort study was to compare two groups of cats with lower respiratory tract disease, one with Mycoplasma felis detected by PCR in the bronchoalveolar lavage fluid (BALF) (M+) and the other without (M-), with regard to signalment, clinical signs, diagnostic results, treatment response and survival.

METHODS

All cats for which M felis was investigated by PCR in BALF between 2016 and 2023 were included. Cats with evidence of oropharyngeal contamination, or for which PCR results were under the quantification level, or without follow-up information were excluded. Cats that had received antibiotics effective against M felis before BALF collection were excluded if PCR results were negative. Follow-up information was retrieved from the medical records and by contacting referring veterinarians and owners.

RESULTS

A total of 55 cats were included (19 in the M+ group and 36 in the M- group). Significant differences were detected between the two groups in the prevalence of systemic signs (M+: 0%, M-: 28%; P = 0.01), bronchial collapse on bronchoscopy (M+: 28%, M-: 6%; P = 0.03), radiographic alveolar lesions (M+: 57%, M-: 24%; P = 0.04), and percentage of neutrophils (M+: 65%, M-: 35%; P = 0.002) and eosinophils (M+: 9%, M-: 25%; P = 0.03) in the BALF. Antibiotics were used more frequently in M+ cats (M+: 90%, M-: 42%; P = 0.001) than in M- cats. No significant difference was found in treatment response (short term: P = 0.94, long term: P = 0.28) and risk of death (P = 0.42) between the two groups.

CONCLUSIONS AND RELEVANCE

The presence of radiographic alveolar lesions and neutrophilia in BALF was significantly associated with the detection of M felis in BALF. This association might be causal, consequential or contextual (ie, sharing the same cause). The detection of M felis in BALF did not negatively impact prognosis but the necessity to treat M felis using targeted antibiotics remains to be determined.

Diagnostic significance of HRCT imaging features in adult mycoplasma pneumonia: a retrospective study

Mycoplasma pneumoniae pneumonia (MPP) often overlaps with the clinical manifestations and chest imaging manifestations of other types of community-acquired pneumonia (CAP). We retrospectively analyzed the clinical and imaging data of a group of patients with CAP, summarized their clinical and imaging characteristics, and discussed the diagnostic significance of their certain HRCT findings. The HRCT findings of CAP researched in our study included tree-in-bud sign (TIB), ground-glass opacity (GGO), tree fog sign (TIB + GGO), bronchial wall thickening, air-bronchogram, pleural effusion and cavity. The HRCT findings of all cases were analyzed. Among the 200 cases of MPP, 174 cases showed the TIB, 193 showed the GGO, 175 showed the tree fog sign, 181 lacked air-bronchogram. In case taking the tree fog sign and lack of air-bronchogram simultaneously as an index to distinguish MPP from OCAP, the sensitivity was 87.5%, the specificity was 97.5%, the accuracy was 92.5%. This study showed that that specific HRCT findings could be used to distinguish MPP from OCAP. The combined HRCT findings including the tree fog sign and lacked air-bronchogram simultaneously would contribute to a more accurate diagnosis of MPP.

Quantitative CT comparison between COVID-19 and mycoplasma pneumonia suspected as COVID-19: a longitudinal study

OBJECTIVE

The purpose of this study was to compare imaging features between COVID-19 and mycoplasma pneumonia (MP).

MATERIALS AND METHODS

The data of patients with mild COVID-19 and MP who underwent chest computed tomography (CT) examination from February 1, 2020 to April 17, 2020 were retrospectively analyzed. The Pneumonia-CT-LKM-PP model based on a deep learning algorithm was used to automatically quantify the number, volume, and involved lobes of pulmonary lesions, and longitudinal changes in quantitative parameters were assessed in three CT follow-ups.

RESULTS

A total of 10 patients with mild COVID-19 and 13 patients with MP were included in this study. There was no difference in lymphocyte counts at baseline between the two groups (1.43 ± 0.45 vs. 1.44 ± 0.50, p = 0.279). C-reactive protein levels were significantly higher in MP group than in COVID-19 group (p < 0.05). The number, volume, and involved lobes of pulmonary lesions reached a peak in 7-14 days in the COVID-19 group, but there was no peak or declining trend over time in the MP group (p < 0.05).

CONCLUSION

Based on the longitudinal changes of quantitative CT, pulmonary lesions peaked at 7-14 days in patients with COVID-19, and this may be useful to distinguish COVID-19 from MP and evaluate curative effects and prognosis.

A fulminant pneumonia due to Mycoplasma pneumoniae – Case report and literature review

Fulminant pneumonia due to Mycoplasma pneumoniae [MP] is quite rare even though there is a high prevalence of Mycoplasma species infection in the general population.

We report a case of an atypical pneumonia with Acute Respiratory Distress Syndrome (ARDS) due to Mycoplasma pneumoniae in a young female and the clinical challenges encountered along with the current literature review.

Epidemiology and clinical characteristics of pathogens positive in hospitalized children with segmental/lobar pattern pneumonia

Background

The occurrence of segmental/lobar pattern pneumonia (S/L-PP) in children has recently increased. The pathogens of the disease may change for the misuse of antibiotics and the application of vaccines. Therefore, pathogens positive in hospitalized children with S/L-PP and their association with clinical characteristics may have changed. The aim of this study was to analyze the pathogens positive in hospitalized children with S/L-PP and their association with clinical characteristics.

Method

The current study analyzed the epidemiological and clinical characteristics of pathogens positive in children with S/L-PP under 14 years old at a single hospital between 1st Jan 2014 and 31st Dec 2018 retrospectively. The pathogens were detected by microbial cultivation, indirect immunofluorescence of the kit (PNEUMOSLIDE IgM), Elisa, and/or real-time PCR in the samples of the patients.

Results

A total of 593 children with S/L-PP received treatment at a single hospital during the study period by inclusion criteria. Four hundred fifty-one patients were single positive for one pathogen and 83 patients were positive for at least 2 pathogens. Mycoplasma pneumoniae (M.pneumoniae) (72.34%) was the most commonly detected pathogen, followed by Streptococcus pneumoniae (S.pneumoniae) (8.77%). The prevalence of M.pneumoniae in children with S/L-PP increased with time (p < 0.05). The positive rate of M.pneumoniae increased with ages of patients (p < 0.05). M.pneumoniae was statistically associated with the extrapulmonary manifestations while S.pneumoniae was statistically associated with abnormal white blood cells (WBCs) and C reactive proteins (CRPs) (p < 0.05).

Conclusion

M.pneumoniae was the most positive pathogen in children with S/L-PP. The positive rate of M.pneumoniae in children with S/L-PP increased with time and the ages of children. M.pneumoniae was associated with extrapulmonary manifestations while S.pneumoniae was associated with abnormal WBCs and CRPs.

Ability of high-resolution computed tomography to distinguish Mycoplasma pneumoniae pneumonia from other bacterial pneumonia: Significance of lateral bronchial lesions, less air bronchogram, and no peripheral predominance

BACKGROUND

No study has investigated the capability of high-resolution computed tomography (HRCT) to detect a lateral bronchus abnormality, degree of air bronchogram, and distribution of affected lesions in the diagnosis of Mycoplasma pneumoniae pneumonia (MPP).

METHODS

We prospectively enrolled patients with serologically-confirmed MPP or culture-confirmed other bacterial pneumonia (OBP). The distribution of affected areas, abnormalities in lateral bronchial lesions, the degree of air bronchogram, and previously reported findings on HRCT were evaluated for MPP and OBP. Predictive HRCT findings for MPP were determined by logistic regression analysis. We provisionally designed our HRCT criteria (negative, probable, or highly suspected) for diagnosing MPP and investigated the diagnostic yield of the HRCT criteria.

RESULTS

Sixty-three MPP and 126 OBP patients were included in this study. Logistic regression analysis showed that the absence of peripheral predominance, bronchial wall thickening, lateral bronchial wall thickening, intralobular or lobular ground-glass opacities, intralobular ground-glass opacities connected to a lateral bronchus, and less air bronchogram in infiltrates were significant predictors of MPP. Our HRCT criteria showed that the sensitivity and specificity in negative, probable, and highly suspected MPP were 0.0 and 0.33, 1.0 and 0.69, and 0.5 and 0.98, respectively.

CONCLUSIONS

HRCT had considerable ability to detect a lateral bronchial abnormality and to diagnose or rule out MPP based on the distribution of affected areas, abnormalities in lateral bronchial lesions, and the degree of air bronchogram in the infiltrates.

Correlation between chest radiographic findings and clinical features in hospitalized children with Mycoplasma pneumoniae pneumonia

Background

Radiologic evaluation of children with Mycoplasma pneumoniae is important for diagnosis and management.

Objective

To investigate the correlation between chest radiographic findings and the clinical features in children with Mycoplasma pneumoniae pneumonia.

Materials and methods

This study included 393 hospitalized children diagnosed with M. pneumoniae pneumonia between January 2000 and August 2016. Their clinical features and chest radiographs were reviewed. Radiographic findings were categorized and grouped as consolidation group (lobar or segmental consolidation) and non-consolidation group (patchy infiltration, localized reticulonodular infiltration, or parahilar peribronchial infiltration).

Results

Lobar or segmental consolidation (37%) was the most common finding, followed by parahilar or peribronchial infiltration (27%), localized reticulonodular infiltration (21%) and patchy infiltration (15%). The consolidation group was more frequently accompanied by pleural effusions (63%), compared to the non-consolidation group (16%). Compared with patients in the non-consolidation group, those in the consolidation group were associated with a significantly higher rate of hypoxia, tachypnea, tachycardia, extrapulmonary manifestations, prolonged fever, and longer periods of anti-mycoplasma therapy and hospitalization. Lobar or segmental consolidation was significantly more frequent in children ≥5 years old (44%) compared with children 2–5 years old (34%) and <2 years old (13%). Parahilar peribronchial infiltration was significantly more frequent in children <2 years old (56%) compared with children 2–5 years old (32%) and ≥5 years old (18%).

Conclusion

The chest radiographic findings of children with M. pneumoniae pneumonia correlate well with the clinical features. Consolidative lesions were frequently observed in older children and were associated with more severe clinical features.

Relationship Between Clinical Features and Computed Tomographic Findings in Hospitalized Adult Patients With Community-Acquired Pneumonia

Background

Data on the relationship between the clinical and microbiological features of community-acquired pneumonia (CAP) and its computed tomography (CT) findings are limited. The aim of the present study was to investigate the clinic-microbiological features of patients with CAP presenting with ground-glass opacity (GGO) and centrilobular nodules or tree-in-bud pattern on CT images.

Methods

Patients with CAP who underwent a CT scan at presentation were retrospectively classified using CT findings into consolidation, GGO and bronchiolitis groups. These 3 groups were compared in terms of clinical parameters and microbiological data.

Results

A total of 40 patients (2.4%) were allocated to the bronchiolitis group and 46 (2.8%) to the GGO group. The most common pathogen in the bronchiolitis group was Mycoplasma pneumoniae, which was significantly more frequently isolated in this group. The bronchiolitis group was characterized by a higher percentage of cough, a lower percentage of chest pain and lower blood levels of inflammatory markers. Common pathogens in the GGO group were not significantly different from those in the other 2 groups. Unlike that observed in the consolidation group, complicated parapneumonic effusion or empyema was not observed in the bronchiolitis or GGO group. Outcome variables were similar in the 3 groups.

Conclusions

The bronchiolitis group was characterized by a higher frequency of M. pneumoniae and a less severe form of CAP. The GGO and consolidation groups was similar with respect to causative microorganisms and the clinical features of CAP. No patient in the bronchiolitis or GGO group exhibited complicated parapneumonic effusion or empyema.

Thoracic Imaging Features of Legionnaire's Disease

Imaging examinations are often performed in patients with Legionnaires' disease. The literature to date has documented that the imaging findings in this disorder are relatively nonspecific, and it is therefore difficult to prospectively differentiate legionella pneumonia from other forms of pneumonia, and from other noninfectious thoracic processes. Through a review of clinical cases and the literature, our objective is for the reader to gain a better understanding of the spectrum of radiographic manifestations of Legionnaires' disease.

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.

Epidemiology and clinical features of segmental/lobar pattern Mycoplasma pneumoniae pneumonia: A ten-year retrospective clinical study

Mycoplasma pneumoniae plays an important role in community-acquired pneumonia. However, epidemiological and clinical studies on the segmental/lobar pattern (S/L) radiographic-pathologic subtype of pediatric Mycoplasma pneumoniae pneumonia (MPP) are rare. The current study retrospectively analyzed the epidemiological and clinical characteristics of pediatric MPP patients. A total of 1,933 children with MPP received treatment at a single hospital between 2000 and 2009, of which 684 (35.4%) were diagnosed with S/L-MPP. The annual incidence of S/L-MPP in children with MPP increased throughout the duration of this study (from 6.4 to 59.6%, P<0.001), which was particularly evident after 2003. S/L-MPP was predominantly found in pre-school-aged children (4-6 years old; 56.6%). Compared with non-S/L-MPP, S/L-MPP was more closely associated with severe manifestations, including higher rates of fever (90.2 vs. 83.3%), pleural effusion (3.9 vs. 1.3%), extrapulmonary manifestations (26.2 vs. 21.2%), abnormal white blood cell counts (65.5 vs. 55.2%), abnormal C-reactive protein levels (30.9 vs. 23.7%) and bacterial co-infection (32.0 vs. 24.9%), as well as longer durations of fever (4.13±4.28 vs. 3.02±2.22 days) and hospitalization (12.70±4.54 vs. 9.22±5.12 days). Older S/L-MPP patients showed higher rates and longer durations of fever and cough; however, they also displayed a lower rate of extrapulmonary manifestations when compared with younger patients. In conclusion, the annual incidence of S/L-MPP has increased in recent years. Pre-school-aged children (4-6 years) with MPP are more likely to display a segmental/lobar pattern, which is associated with more severe clinical manifestations than other MPP infection patterns.

Differentiation between mycoplasma and viral community-acquired pneumonia in children with lobe or multi foci infiltration: a retrospective case study

OBJECTIVES

To analyse the clinical features, inflammatory markers and radiographs of community-acquired pneumonia (CAP) cases with lobe or multi foci infiltration; with a special focus on factors which allow the differential diagnosis of viral and mycoplasma pneumonia.

SETTING

Retrospective chart review of CAP cases in a large university teaching hospital.

PARTICIPANTS

126 paediatric CAP cases, with lobe or multi foci infiltration, presenting between May 2012 and April 2013. Demographic data, clinical presentation on admission or referral, laboratory tests, prior history, and radiography were collected for each case if available.

PRIMARY AND SECONDARY OUTCOME MEASURES

We used univariate and multivariate logistic regression to determine the significant factors which allow the differential diagnosis of viral and mycoplasma CAP with lobe or multi foci infiltration.

RESULTS

There were 71 (56%) male and 55 (44%) female CAP cases with lobar or multi foci infiltration. 70 pneumonia cases were caused by Mycoplasma pneumoniae and 18 by viruses. Univariate analysis of the mycoplasma and viral causes of the CAP revealed that increased respiratory rate, wheeze, male gender and lymphocyte percentage were the factors associated with the differentiation of mycoplasma and viral aetiologies of pneumonia (p<0.05). A stepwise logistic regression analysis was performed to assess independent factors which allow the differential diagnosis of viral and mycoplasma pneumonia. Increased respiratory rate, wheeze, and lymphocyte percentage were reliable independent factors which allow the differential diagnosis of viral and mycoplasma CAP with lobar or multi foci infiltration.

CONCLUSIONS

Whether the CAP with lobar or multi foci infiltration was caused by mycoplasma species or viruses could not be inferred from the radiological patterns. Wheeze, lymphocyte percentage and respiratory rate were independent factors which allowed the differential diagnosis of viral and mycoplasma CAP with lobar or multi foci infiltration.

Novel aspects on the pathogenesis of Mycoplasma pneumoniae pneumonia and therapeutic implications

Mycoplasma pneumoniae (Mp) is a leading cause of community acquired pneumonia. Knowledge regarding Mp pneumonia obtained from animal models or human subjects has been discussed in many different reports. Accumulated expertise concerning this critical issue has been hard to apply clinically, and potential problems may remain undiscovered. Therefore, our multidisciplinary team extensively reviewed the literature regarding Mp pneumonia, and compared findings from animal models with those from human subjects. In human beings, the characteristic pathological features of Mp pneumonia have been reported as alveolar infiltration with neutrophils and lymphocytes and lymphocyte/plasma cell infiltrates in the peri-bronchovascular area. Herein, we demonstrated the novel aspects of Mp pneumonia that the severity of the Mp pneumonia seemed to depend on the host innate immunity to the Mp, which might be accelerated by antecedent Mp exposure (re-exposure or latent respiratory infection) through up-regulation of Toll-like receptor 2 expression on bronchial epithelial cells and alveolar macrophages. The macrolides therapy might be beneficial for the patients with macrolide-resistant Mp pneumonia via not bacteriological but immunomodulative effects. This exhaustive review focuses on pathogenesis and extends to some therapeutic implications such as clarithromycin, and discusses the various diverse aspects of Mp pneumonia. It is our hope that this might lead to new insights into this common respiratory disease.

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.

Pneumonia in the immunocompetent patient

Pneumonia is an acute inflammation of the lower respiratory tract. Lower respiratory tract infection is a major cause of mortality worldwide. Pneumonia is most common at the extremes of life. Predisposing factors in children include an under-developed immune system together with other factors, such as malnutrition and over-crowding. In adults, tobacco smoking is the single most important preventable risk factor. The commonest infecting organisms in children are respiratory viruses and Streptoccocus pneumoniae. In adults, pneumonia can be broadly classified, on the basis of chest radiographic appearance, into lobar pneumonia, bronchopneumonia and pneumonia producing an interstitial pattern. Lobar pneumonia is most commonly associated with community acquired pneumonia, bronchopneumonia with hospital acquired infection and an interstitial pattern with the so called atypical pneumonias, which can be caused by viruses or organisms such as Mycoplasma pneumoniae. Most cases of pneumonia can be managed with chest radiographs as the only form of imaging, but CT can detect pneumonia not visible on the chest radiograph and may be of value, particularly in the hospital setting. Complications of pneumonia include pleural effusion, empyema and lung abscess. The chest radiograph may initially indicate an effusion but ultrasound is more sensitive, allows characterisation in some cases and can guide catheter placement for drainage. CT can also be used to characterise and estimate the extent of pleural disease. Most lung abscesses respond to medical therapy, with surgery and image guided catheter drainage serving as options for those cases who do not respond.

Pulmonary infections

This paper reviews the most common imaging findings of pulmonary infection in children. Pneumonia is a leading cause of mortality in children in developing and industrialized countries. While the imaging findings usually are nonspecific, correlation with the patient's age, immune status and pertinent history can limit the differential diagnoses. The paper will review the common and unique features of pneumonia caused by specific organisms and in specific patient populations.

Mycoplasma pneumoniae bronchiolitis in adults: clinicoradiologic features and clinical course

The clinicoradiologic features of Mycoplasma pneumoniae bronchiolitis in adults remain unclear. 29 patients with M. pneumoniae infection were collected and classified by computed tomographic findings (bronchiolitis (n=8) and pneumonia (n=21)). M. pneumoniae bronchiolitis is not rare in adults and is clinically similar to M. pneumoniae pneumonia, despite radiographic differences.

Radiographic features of Mycoplasma pneumoniae pneumonia: differential diagnosis and performance timing

BACKGROUND

The Japanese Respiratory Society guidelines propose a differential diagnosis for atypical pneumonia and bacterial pneumonia using a scoring system for the selection of appropriate antibiotic. In order to improve this scoring system, the guidelines are seeking new specific parameter. The purpose of this study was to clarify the pattern of abnormalities with Mycoplasma pneumoniae pneumonia on chest computed tomography (CT) and whether the radiographic findings could distinguish M. pneumoniae pneumonia from Streptococcus pneumoniae pneumonia.

METHODS

A retrospective review was performed of the CT findings of 64 cases and 68 cases where M. pneumoniae and S. pneumoniae, respectively, were the only pathogen identified by the panel of diagnostic tests used.

RESULTS

Of the 64 patients with M. pneumoniae pneumonia, bronchial wall thickening was observed most frequently (81%), followed by centrilobular nodules (78%), ground-glass attenuation (78%), and consolidation (61%). Bronchial wall thickening and centrilobular nodules were observed more often in M. pneumoniae patients than in S. pneumoniae patients (p < 0.0001). The presence of bilateral bronchial wall thickening or centrilobular nodules was only seen in patients with M. pneumoniae pneumonia. Using the scoring system of the Japanese Respiratory Society guidelines and chest CT findings, 97% of M. pneumoniae patients were suspected to be M. pneumoniae pneumonia without serology. When comparing the CT findings between early stage and progressed stage in the same patients with severe pneumonia, the radiographic features of early stage M. pneumoniae pneumonia were not observed clearly in the progressed stage.

CONCLUSION

The present results indicate that the diagnosis of M. pneumoniae pneumonia would appear to be reliable when found with a combination of bronchial wall thickening and centrilobular nodules in the CT findings. However, these CT findings are not observed in progressed severe M. pneumoniae pneumonia patients.

Mycoplasma pneumoniae-associated mucositis with minimal skin manifestations

Mycoplasma pneumoniae-associated mucositis is a rarely described complication of M. pneumoniae infection presenting with ocular, oral, and genital involvement but without the typical skin lesions seen in Stevens-Johnson syndrome. A 27-year-old man with a past history of asthma presented at the emergency room with a 1-week history of cough (initially non-productive but subsequently associated with non-bloody mucopurulent sputum), fever, myalgias, headache, and progressive dyspnea. Two days before admission he had commenced amoxicillin/clavulanic acid with no improvement. The patient reported bilateral conjunctival injection and hemorrhagic ulcers on the lips commencing the day prior to admission. Physical examination revealed fever (39 degrees C), bilateral exudative conjunctivitis, painful hemorrhagic ulcers on the lips, tongue, and oral mucosa, small scrotal erosions, erythema of the penile meatus, and small erythematous bullae on the dorsum of each hand; subsequently, the patient developed bullae at the venipuncture site on his right arm. Laboratory tests revealed positive IgM serology for M. pneumoniae, with titer elevation. The patient was successfully treated with levofloxacin and prednisolone. Our case appears to be the first adult patient described with M. pneumoniae-associated mucositis, which has previously been reported only in pediatric patients. This is also the first reported instance of a case of M. pneumoniae-associated mucositis treated with levofloxacin and prednisolone. M. pneumoniae infection should be considered in all cases of mucositis, and treatment of this condition with levofloxacin and prednisolone seems to be effective.

Atypical pneumonias: current clinical concepts focusing on Legionnaires' disease

PURPOSE OF REVIEW

This review provides clinicians with an overview of the clinical features of the atypical pneumonias. Atypical community-acquired pneumonia pathogens cause systemic infections with pneumonia. The key to the clinical diagnosis of atypical pneumonias depends on recognizing the characteristic pattern of extrapulmonary organ involvement different for each pathogen. As Legionella is likely to present as severe pneumonia and does not respond to beta-lactams, it is important to presumptively diagnose Legionnaires' disease clinically so that Legionella coverage is included in empiric therapy. This study reviews the clinical features and nonspecific laboratory markers of atypical pathogens, focusing on Legionnaires' disease.

RECENT FINDINGS

Case reports/outbreaks increase our understanding of Legionnaires' disease transmission. Both Mycoplasma pneumoniae and Chlamydophilia pneumoniae may cause asthma. Antimicrobial therapy of Chlamydophilia pneumoniae/Mycoplasma pneumoniae is important to decrease person-to-person spread and to decrease potential long-term sequelae.

SUMMARY

Atypical pulmonary pathogens cause systemic infections accompanied by a variety of characteristic extrapulmonary features. Clinically, it is possible to differentiate Legionnaires' disease from the other typical/atypical pneumonias. Rapid clinical diagnosis of atypical pathogens, particularly Legionnaires' disease, is important in selecting effective empiric therapy and prompting definitive laboratory testing.

Early Mycoplasma pneumoniae infection presenting as multiple pulmonary masses: an unusual presentation in a child

Mycoplasma pneumoniae is a major cause of community-acquired pneumonia. Because most children are not imaged prior to onset of clinical symptoms, the appearance of early Mycoplasma infection has not been extensively studied. We present the case of an 11-year-old boy with large pulmonary masses incidentally detected during spine MRI evaluation for scoliosis. Eight days later, the patient developed acute respiratory symptoms, and the masses seen previously had evolved into a diffuse bronchiolitis. Diagnostic testing identified Mycoplasma pneumoniae as the likely etiology. We briefly review chest CT findings of infection by Mycoplasma and compare them to this unusual presentation of Mycoplasma pneumonia with subclinical imaging findings.

Microbiological aspects of bacterial lower respiratory tract illness in children: atypical pathogens

'Atypical' lower respiratory tract pathogens often cause a distinct identifiable syndrome in adults, but in children the clinical presentation of atypical, typical and viral pneumonia is less well differentiated. Specific microbiological investigations are usually required, but an understanding of their strengths and weaknesses is necessary to make interpretation possible. This review examines clinical presentation, microbiology and current evidence surrounding diagnostic techniques for Mycoplasma pneumoniae, Chlamydophila pneumoniae, Chlamydophila psittaci, Bordetella pertussis and Legionella species. Applying an understanding of the investigations to the diagnosis of pneumonia in children may lead to more appropriate patient management by ensuring that they clarify rather than further obscure the diagnosis.

Imaging of Bacterial Pulmonary Infection in the Immunocompetent Patient

Pulmonary infection is a common reason for imaging of the lung and a common incidental finding in immunocompetent patients. Findings on chest radiography are nonspecific in defining acute infection; however, the radiologist should be aware of classically described patterns of infection, including air space, bronchopneumonia, and interstitial patterns. The radiologist must also be aware of potential limitations of the sensitivity of chest radiography. Imaging findings at computed tomography in acute infection have been poorly studied but may be more specific. Aspiration and septic emboli are additional potential radiographic patterns of infection that may be very characteristic in appearance. In the setting of nonresolving pneumonia, the differential diagnosis includes noninfectious causes as well as a variety of atypical infectious agents, specifically, mycobacterial and fungal agents, which have overlapping but distinctive clinical and radiographic presentations.