Identification rate of Legionella species in non-purulent sputum culture is comparable to that in purulent sputum culture in Legionella pneumonia

Many Legionella pneumonia patients do not produce sputum, and it is unknown whether purulent sputum is required for the identification of Legionella species. This study aimed to evaluate the identification rate of Legionella species based on sputum quality and the factors predictive of Legionella infection. This study included Legionella pneumonia patients at Kurashiki Central Hospital from November 2000 to December 2022. Sputum quality, based on gram staining, was classified as the following: Geckler 1/2, 3/6 and 4/5. Geckler 4/5 was defined as purulent sputum. The sputa of 104 of 124 Legionella pneumonia patients were cultured. Fifty-four patients (51.9%) were identified with Legionella species, most of which were Legionella pneumophila serogroup 1 (81.5%). The identification rates of Legionella species according to sputum quality were 57.1% (16/28) in Geckler 1/2 sputum, 50.0% (34/68) in Geckler 3/6 sputum, and 50.0% (4/8) in Geckler 4/5 sputum, which were not significantly different (P = 0.86). On multivariate analysis, pre-culture treatment with anti-Legionella antimicrobials (odds ratio [OR] 0.26, 95% confidence interval [CI] 0.06-0.91), Pneumonia Severity Index class ≥IV (OR 2.57 [95% CI 1.02-6.71]), and intensive care unit admission (OR 3.08, 95% CI 1.06-10.09) correlated with the ability to identify Legionella species, but sputum quality did not (OR 0.88, 95% CI 0.17-4.41). The identification rate of Legionella species in non-purulent sputum was similar to that in purulent sputum. For the diagnosis of Legionella pneumonia, sputum should be collected before administering anti-Legionella antibiotics and cultured regardless of sputum quality.

Quantitative Value of Bacteria Associated with Leukocytes in Differential Diagnosis of Lower Respiratory Tract Infection in Children, in Comparison to Sputum Culture and Procalcitonin

BACKGROUND

The mortality and morbidity rates in children with lower respiratory tract infection (LRTI) remain high.

OBJECTIVE

To describe the number of bacteria that is associated with leukocytes in differential diagnosis of bacterial, mycoplasma, and viral LRTI in children.

METHODS

Sputum smears were Gram stained for counting single-morphology bacteria associated with leukocytes. The differential diagnostic values of bacterial number were assessed in children with LRTI.

RESULTS

The area under the receiver operating characteristic (ROC) curve was 0.95 for bacterial number in the differential diagnosis of bacterial infection from mycoplasma and viral infections. The area under the ROC curve was 0.62 for procalcitonin and 0.94 for bacterial number in the differential diagnosis of bacterial infection from mycoplasma infection.

CONCLUSION

The number of bacteria associated with leukocytes in sputum was valuable and rapid in differential diagnosis of bacterial infection in children with suspected bacterial, mycoplasma, and viral LRTI.

Analysis of the Sputum Culture Spectrum of Children with Respiratory Tract Infection in Wuxi Between 2014 and 2021

Objective

We retrospectively analysed related clinical data to determine the influencing factors to better prevent and treat children's respiratory tract infection.

Methods

The study participants were children with respiratory tract infection who had sputum cultured in our hospital between 2014 and 2021. Sputum samples were extracted using negative suction pressure and sent to the hospital microbiological laboratory for testing. The testing results were analysed.

Results

A total of 4610 sputum samples were collected, and 508 positive samples were detected. The positive rate of pathogenic bacteria was 11.02%. Escherichia coli infection was more common in male patients (11.11%), whereas Haemophilus influenzae infection was more common in female patients (17.54%); the infection rates of these 2 bacteria are increasing annually. There were 304 (59.84%) strains of gram-negative bacteria, 172 (33.86%) strains of gram-positive bacteria and 32 (6.3%) strains of fungi. In children between 0 and 3 years old, the proportions of gram-negative bacteria were significantly higher than those of gram-positive bacteria in 2016-2017, 2018-2019 and 2020-2021 (p < 0.01). In every age group, the constituent ratio of gram-negative bacteria was significantly higher than that of gram-positive bacteria (p < 0.01) except for the 3-6-year age group. The proportion of Staphylococcus aureus in 2014-2015, 2016-2017, 2018-2019 and 2020-2021 was 25.64%, 25.20%, 22.98% and 16.44%, respectively. The proportion of H. influenzae in 2014-2015 was significantly lower than that in other years (p < 0.01). Haemolyticus staphylococcus and E. coli were more common in newborns, accounting for 19.12%.

Conclusion

The pathogens of respiratory tract infection in children change dynamically. There are significant differences in pathogens of respiratory tract infections among different age groups, years and seasons. Clinicians should pay attention to changes in the pathogen spectrum and improve drug resistance monitoring.

Clinical characteristics of respiratory tract infection caused by Klebsiella pneumoniae in immunocompromised patients: a retrospective cohort study

Purpose

With advancements in medical technology and the growth of an aging society, the number of immunocompromised patients has increased progressively. Klebsiella pneumoniae (K. pneumoniae) is one of the most common opportunistic pathogens, causing a severe disease burden. We aimed to further clarify the differences in respiratory tract K. pneumoniae infections between immunocompromised and immunocompetent populations.

Methods

We retrospectively compared cases of respiratory tract K. pneumoniae infection in immunocompromised and immunocompetent patients admitted to Ruijin Hospital in Shanghai between January 2019 and August 2020 to clarify the differences between the two groups.

Results

We enrolled 400 immunocompromised patients and 386 immunocompetent patients. Compared to the immunocompetent group, immunocompromised patients were more likely to develop bacteremia and shock and to require mechanical ventilation support during hospitalization. Immunocompromised patients also had a greater probability of polymicrobial infection and a higher rate of antibacterial resistance to carbapenem, which resulted in a higher intensive care unit admission rate, 30-day case fatality rate (CFR), and 6-month CFR. Multivariate analysis indicated that immunocompromised patients with respiratory diseases (odds ratio [OR], 2.189; 95% confidence interval [CI], 1.103-4.344; P = 0.025) and cardiovascular diseases (OR, 2.008; 95% CI, 1.055-3.822; P = 0.034), using mechanical ventilation (OR, 3.982; 95% CI, 2.053-7.722; P = 0.000), or infected with multidrug-resistant K. pneumoniae (OR, 3.870; 95%, 1.577-9.498; P = 0.003) were more likely to have a higher 30-day CFR.

Conclusion

The disease burden of K. pneumoniae infection in immunocompromised patients is high. Immunocompromised patients who presented with respiratory diseases and cardiovascular diseases, used mechanical ventilation, or were infected with multidrug-resistant K. pneumoniae experienced a higher 30-day mortality rate.

Performance of Xpert MTB/RIF and sputum microscopy compared to sputum culture for diagnosis of tuberculosis in seven hospitals in Indonesia

Introduction

Tuberculosis (TB) is a major public health concern in Indonesia, where the incidence was 301 cases per 100,000 inhabitants in 2020 and the prevalence of multi-drug resistant (MDR) TB is increasing. Diagnostic testing approaches vary across Indonesia due to resource limitations. Acid-fast bacilli (AFB) smear is widely used, though Xpert MTB/RIF has been the preferred assay for detecting TB and rifampicin resistance since 2012 due to higher sensitivity and ability to rapidly identify rifampicin resistance. However, <1,000 Xpert instruments were available in Indonesia as of 2020 and the Xpert supply chain has suffered interruptions.

Methods

We compared the performance of Xpert MTB/RIF and AFB smear to facilitate optimization of TB case identification. We analyzed baseline data from a cohort study of adults with pulmonary TB conducted at seven hospitals across Indonesia. We evaluated sensitivity and specificity of AFB smear and Xpert MTB/RIF using Mycobacterium tuberculosis (Mtb) culture as the gold standard, factors associated with assay results, and consistency of Xpert MTB/RIF with drug susceptibility test (DST) in detecting rifampicin resistance.

Results

Sensitivity of AFB smear was significantly lower than Xpert MTB/RIF (86.2 vs. 97.4%, p-value <0.001), but specificity was significantly better (86.7 vs. 73.3%, p-value <0.001). Performance varied by hospital. Positivity rate for AFB smear and Mtb culture was higher in subjects with pulmonary cavities and in morning sputum samples. Consistency of Xpert MTB/RIF with DST was lower in those with rifampicin- sensitive TB by DST.

Discussion

Additional evaluation using sputa from primary and secondary Indonesian health centers will increase the generalizability of the assessment of AFB smear and Xpert MTB/RIF performance, and better inform health policy.

Clinical trial registration

[https://clinicaltrials.gov/], identifier [NCT027 58236].

Bacterial Species and Inflammatory Cell Variability in Respiratory Tracts of Patients with Chronic Obstructive Pulmonary Disease Exacerbation: A Multicentric Study

Background and Aim

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) has profound effects on disease progression and patients' quality of life. Emerging evidence suggests an association between alterations in the respiratory microbiome flora species and airway inflammation in patients with AECOPD. The present study aimed to describe the inflammatory cells and bacterial microbiome distributions in respiratory tract in Egyptian patients with AECOPD.

Subjects and Methods

The present cross-sectional study included 208 patients with AECOPD. Sputum and broncho-alveolar lavage samples from the studied patients were submitted to microbial cultures using appropriate media. Total and differential leukocytic counts and were done via automated cell counter.

Results

The present study included 208 AECOPD patients. They comprised 167 males (80.3%) and 41 females (19.7%) with an age of 57.9 ± 4.9 years. AECOPD was categorized as mild, moderate and severe in 30.8%, 43.3% and 26%, respectively. Sputum samples had significantly higher TLC, neutrophil percent and eosinophil percent when compared with BAL samples. In contrast, lymphocyte percent was significantly higher in BAL samples. Sputum specimens had significantly lower frequency of positive growths (70.2% versus 86.5%, p = 0.001). Among the identified organisms, sputum specimens had significantly lower frequency of Strept. pneumoniae (14.4% versus 30.3%, p = 0.001), Klebsiella pneumoniae (19.7% versus 31.7%, p = 0.024), Haemophilus influenzae (12.5% versus 26.9%, p = 0.011), Pseudomonas aeruginosa (2.9% versus 10%, p = 0.019) and Acinetobacter spp. (1.9% versus 7.2%, p = 0.012) growths when compared with BAL samples.

Conclusion

The present study could identify a distinctive pattern of inflammatory cell distribution in sputum and BAL samples of AECOPD patients. The most commonly isolated organisms were Klebsiella pneumoniae and Strept. pneumoniae.

Mycobacterium iranicum pulmonary disease in an elderly patient with extensive usual interstitial pneumonia: Case report

We report the first case of Mycobacterium iranicum pulmonary disease in an elderly patient with extensive usual interstitial pneumonia and traction bronchiectasis. He was treated with oral doxycycline, ciprofloxacin, and sulfamethoxazole/trimethoprim daily for 9 months. This was associated with eradication of the microorganism in the sputum and steady weight gain.

Tuberculosis screening among newly arrived asylum seekers in Denmark

BACKGROUND

Tuberculosis (TB) screening programmes among asylum seekers tend to focus on chest radiography (CXR) for early diagnosis, whereas knowledge on sputum examination is limited. We evaluated active TB screening using CXR and sputum culture among asylum seekers arriving in Denmark. In addition, we assessed the coverage of a voluntary health assessment.

METHODS

Between 1 February 2017 and 31 March 2019, all newly arrived asylum seekers in Denmark ≥ 18 years from TB high-incidence countries or risk groups, who attended a voluntary general health assessment, were offered active TB screening with CXR and spot sputum examination. Sputum samples were examined by culture and smear microscopy.

RESULTS

Coverage of the general health assessment was 65.1%. Among 1,154 referred for active TB screening, 923 (80.0%) attended. Of these, 854 were screened by CXR and one case of active TB was identified equivalent to a yield of 0.12%. Sputum samples were collected from 758 and one M. tuberculosis culture-positive TB case (also identified by CXR) was identified, equivalent to a yield of 0.13%. No cases were found by sputum culture screening only. In addition, screening found three cases of malignant disease.

CONCLUSION

We suggest that TB screening should focus on asylum seekers from TB high-incidence countries. Furthermore, early health assessments should be of high priority to ensure migrant health.

Diagnostic Validity of Gastric Aspirate Culture in Nontuberculous Mycobacterial Pulmonary Disease

Rationale: Although gastric aspirate culture is used for diagnosing pulmonary tuberculosis, its usefulness in diagnosing pulmonary infections of nontuberculous mycobacteria (NTM) is unknown.Objectives: To investigate the diagnostic validity of gastric aspirate culture for acid-fast bacilli in NTM pulmonary disease (NTM-PD).Methods: Gastric aspirates were collected from patients with suspected NTM-PD at the Osaka Toneyama Medical Center between December 2006 and February 2018. Patients with a final diagnosis of pulmonary tuberculosis, an observation period of less than 6 months, or fewer than three conducted sputum cultures were excluded from the study. NTM-PD was diagnosed as per American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) criteria. We retrospectively examined the diagnostic validity of gastric aspirate culture in Mycobacterium avium complex (MAC)-PD and M. kansasii-PD by comparing culture results with final diagnoses. This was done first for all patients, and subsequently for patients with negative results for early sputum cultures. In addition, we compared the time required for an NTM-PD diagnosis based on gastric aspiration with that based on ATS/IDSA criteria.Results: Among 475 total patients, 119 (25.1%) had positive NTM gastric aspirate cultures and 154 (32.4%) fulfilled the ATS/IDSA criteria for NTM-PD. The sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPVs) of gastric aspiration were 63.9%, 95.8%, 83.5%, and 88.8% in MAC-PD and 82.4%, 99.6%, 87.5%, and 99.3% in M. kansasii-PD, respectively. Sensitivity, specificity, PPV, and NPV of gastric aspirate cultures of the 378 patients who were undiagnosed based on sputum culture within 120 days were 34.0%, 95.5%, 51.6%, and 91.1% for MAC-PD and 75.0%, 99.5%, 60.0%, and 99.7% for M. kansasii-PD, respectively. Furthermore, gastric aspirate cultures tested in addition to bronchoscopy yielded incremental sensitivity of 8.7% (95.7% vs. 87.0%) and an NPV of 1.3% (99.3% vs. 98.0%) in MAC-PD. In patients with NTM-PD with NTM-positive gastric aspirate cultures, the period between gastric aspirate collection and the positive culture result was shorter than the time between gastric aspirate collection and NTM-PD diagnosis (6 [9-36] d vs. 25 [12-69] d, median [interquartile range], P < 0.0001].Conclusions: In settings where acid-fast bacilli pulmonary diseases are suspected, gastric aspirate culture may be helpful for diagnosing MAC-PD and M. kansasii-PD.

Blind Spots of Traditional Microbiological Tests for Severe Community-Acquired Pneumonia in Adults and Availability of Nonculture Techniques: A Nationwide Survey of Physicians in China

BACKGROUND

In China, no national survey has been conducted to evaluate physicians' attitudes and compliance with guidelines in the management of adult patients with community-acquired pneumonia (CAP). Therefore, this study aimed to evaluate physicians' awareness of the use of microbiological tests in the management of severe CAP (SCAP) and to investigate the availability of nonculture tests in China.

METHODS

A nationwide electronic questionnaire survey was conducted among Chinese physicians between March and July 2018, which assessed their viewpoints concerning the issues in the management of SCAP.

RESULTS

A total of 6333 physicians completed this survey, evenly covering all career stages. Among these, 3208 (50.6%) and 1936 (30.6%) had blind spots in the application of blood and sputum cultures in the management of SCAP, respectively. Nonteaching hospital, nonrespirologists, and junior career stage were independently associated with misunderstandings. Regarding nonculture methods, 52.7% of the facilities had no access to polymerase chain reaction-based pathogen detection tests. The accessibility of urinary antigen tests for Streptococcus pneumoniae (42.5%) and Legionella pneumophila (38.5%) was also low. The main barriers were inland and remote region, lower hospital level, and nonteaching hospital.

CONCLUSIONS

Insufficient use of sputum and blood cultures, together with low accessibility of major nonculture techniques, were noticeable barriers to achieving microbiological diagnosis of SCAP in China. To help curb the overuse of broad-spectrum antibiotics, further measures should be taken to raise awareness among nonspecialists and promote rapid nonculture tests, especially in nonteaching hospitals and developing regions.

Clinical and Microbiological Features of Asymptomatic SARS-CoV-2 Infection and Mild COVID-19 in Seven Crewmembers of a Cruise Ship

Objective To describe the clinical features and clinical course of individuals diagnosed with asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or mild coronavirus disease (COVID)-19. Patients The study participants consisted of 7 crewmembers of the passenger cruise-liner, Diamond Princess, who were admitted to our hospital after becoming infected with SARS-CoV-2 aboard the ship. Methods The data on patient background and biochemical test results were obtained from the patients' medical records. All patients had a chest X-ray, and a throat swab and sputum samples were sent for culture on admission. Results The median age of the 7 patients, of whom 4 were male and 3 were female, was 39 years (range: 23-47 years). On admission, none of them had fever, but 4 (57%) had a cough. None of them showed any signs of organ damage on laboratory testing. Chest X-ray showed pneumonia in one individual, which resolved spontaneously, while the other 6 had normal chest X-ray findings. Culture of throat swabs and sputum samples revealed that 4 patients (57%) had bacterial upper respiratory infections (Haemophilus influenzae, Klebsiella pneumoniae, and Staphylococcus aureus). The period from a positive polymerase chain reaction (PCR) test to negative conversion ranged from 5 to 13 days, with a median of 8 days. Conclusion Healthy young adults without risk factors who acquire SARS-CoV-2 infection may have an asymptomatic infection or may experience mild COVID-19. In addition to obesity, an older age, underlying illness, and being overweight can lead to a risk of exacerbation; thus, hospital management for such individuals may be desirable. Culturing respiratory samples may be useful for diagnosing secondary bacterial pneumonia.

Diagnostic performance of the Sputum Gram Stain in predicting sputum culture results for critically ill pediatric patients with pneumonia

BACKGROUND

The sputum Gram stain is an inexpensive, rapid, and convenient laboratory method that predicts the bacterial pathogens in patients with pneumonia. This study aimed to evaluate the diagnostic performance of this method in predicting sputum culture results for critically ill pediatric patients.

METHODS

From June 2008 to June 2018, patients with pneumonia with an endotracheal or a tracheostomy tube in place in the Pediatric Intensive Care Unit at Changhua Christian Hospital were enrolled retrospectively. Sputum was collected from each patient via the artificial airway for Gram stain and culture evaluations of bacterial pathogens. Mixed culture results were excluded. A successful prediction was defined as a match of the sputum Gram stain and culture results.

RESULTS

A total of 622 records were reviewed, of which 542 were analyzed. Haemophilus influenzae, Pseudomonas aeruginosa, and Streptococcus pneumoniae were the three most common pathogens found. The overall prediction success rate of the sputum Gram stain was 59.23%. The sensitivity of the method in predicting gram-negative bacilli (GNB), gram-negative cocci (GNC), and gram-positive cocci (GPC) was 0.45, 0.67, and 0.61, respectively. Its specificity in predicting GNB, GNC, and GPC was 0.87, 0.98, and 0.87, respectively. Its positive likelihood ratio in predicting GNB, GNC, and GPC was 3.46, 33.50, and 4.69, respectively. The highest prediction success rate among all pathogens was for GNC.

CONCLUSION

The sputum Gram stain had high specificity and relatively low sensitivity in predicting the bacterial pathogens in critically ill pediatric patients. Its high specificity in predicting sputum culture results means that clinicians can confidently use sputum Gram stain results to guide their antibiotic choice for treatment.

Aerosol Transmission of Aspergillus fumigatus in Cystic Fibrosis Patients in the Netherlands

We collected sputum samples and cough plates from 15 cystic fibrosis patients in the Netherlands who were colonized with Aspergillus fumigatus; we recovered A. fumigatus of the same genotype in cough aerosols and sputum samples from 2 patients. The belief that transmission of A. fumigatus from cystic fibrosis patients does not occur should be reconsidered.

Frequency of Circulating CD4+Ki67+HLA-DR- T Regulatory Cells Prior to Treatment for Multidrug Resistant Tuberculosis Can Differentiate the Severity of Disease and Predict Time to Culture Conversion

Identifying a blood circulating cellular biomarker that can be used to assess severity of disease and predict the time to culture conversion (TCC) in patients with multidrug resistant tuberculosis (MDR-TB) would facilitate monitoring response to treatment and may be of value in the design of future drug trials. We report on the frequency of blood Ki67⁺HLA-DR^- CD4+ T regulatory (Treg) cells in predicting microbiological outcome before initiating second-line treatment for MDR-TB. Fifty-one patients with MDR-TB were enrolled and followed over 18 months; a subset of patients was sputum culture (SC) negative at baseline (n = 9). SC positive patients were divided into two groups, based on median TCC: rapid responders (≤71 days TCC; n = 21) and slow responders (>71 days TCC; n = 21). Whole blood at baseline, months 2 and 6 was stimulated with M tuberculosis (Mtb) antigens and Treg cells were then identified as CD3⁺CD4⁺CD25^hiFoxP3⁺CD127^-CD69^- and further delineated as Ki67⁺HLA-DR^- Treg. The frequency of these cells was significantly enlarged at baseline in SC positive relative to SC negative and smear positive relative to smear negative patients and in those with lung cavitation. This difference was further supported by unsupervised hierarchical clustering showing a significant grouping at baseline of total and early differentiated memory Treg cells in slow responders. Conversely, there was a clustering of a lower proportion of Treg cells and activated IFNγ-expressing T cells at baseline in the rapid responders. Examining changes over time revealed a more gradual reduction of Treg cells in slow responders relative to rapid responders to treatment. Receiver operating curve analysis showed that baseline Mtb-stimulated Ki67⁺HLA-DR^- Treg cells could predict the TCC of MDR-TB treatment response with 81.2% sensitivity and 85% specificity (AUC of 0.87, p < 0.0001), but this was not the case after 2 months of treatment. In conclusion, our data show that the frequency of a highly defined Mtb-stimulated blood Treg cell population at baseline can discriminate MDR-TB disease severity and predict time to culture clearance.

Accuracy of High-Throughput Nanofluidic PCR-Based Pneumococcal Serotyping and Quantification Assays Using Sputum Samples for Diagnosing Vaccine Serotype Pneumococcal Pneumonia: Analyses by Composite Diagnostic Standards and Bayesian Latent Class Models

The lack of reliable diagnostic tests for detecting vaccine serotype pneumococcal pneumonia (VTPP) remains a challenging issue in pneumococcal vaccine studies. This study assessed the performances of high-throughput nanofluidic PCR-based pneumococcal serotyping and quantification assay methods using sputum samples (the nanofluidic sputum quantitative PCR [Sp-qPCR] assay) to diagnose 13-valent pneumococcal conjugate VTPP compared with the performance of the serotype-specific urinary antigen detection (UAD) assay using urine samples. Adult pneumonia patients from Japan were enrolled in this study between September 2012 and August 2014. Sputum samples were subjected to the nanofluidic Sp-qPCR assay, quantitatively cultured, and serotyped by the Quellung reaction (SpQt). Urine samples were tested by the UAD method. The diagnostic performances of these tests were assessed using composite reference standards and Bayesian latent class models (BLCMs). Among 244 total patients, 27 (11.1%) tested positive with the UAD assay, while 16 (6.6%) and 34 (13.9%) tested positive with the SpQt and nanofluidic Sp-qPCR assays, respectively, with a cutoff value of ≥10⁴ DNA copies/ml, which showed the maximum value of the Youden index. Using BLCMs, the estimated prevalence for VTPP was 12.9%, and the nanofluidic Sp-qPCR assay demonstrated the best performance (sensitivity, 90.2%; specificity, 96.9%), followed by UAD (sensitivity, 75.6%; specificity, 97.9%) and SpQt (sensitivity, 45.8%; specificity, 99.5%). However, when a higher cutoff value of ≥10⁷ DNA copies/ml was applied, the performance of UAD became comparable to that of Sp-qPCR. The vaccine serotype-specific pneumococcal DNA load in sputum among UAD-positive patients was 3 logs higher than that among UAD-negative patients (P = 0.036). The nanofluidic Sp-qPCR assay may be accurate and useful for detecting VTPP among adults.

The Diagnostic Yield of Noninvasive Microbiologic Sputum Sampling in a Cohort of Patients with Clinically Diagnosed Hospital-Acquired Pneumonia

The clinical predictors of positive sputum culture have not been previously reported in hospital-acquired pneumonia (HAP), and data on yield of sputum culture in this setting are scant. Current Infectious Disease Society of America guidelines for HAP recommend noninvasive sputum sampling, though the data for this practice are limited. We assessed the yield of sputum culture in HAP cases at an academic medical center from January 2007 to July 2013. HAP cases were identifi ed by International Classifi cation of Diseases, Ninth Revision-Clinical Modifi cation codes for bacterial pneumonia and all cases were validated by chart review. Our cohort had 1172 hospitalizations with a HAP diagnosis. At least 1 sputum specimen was collected noninvasively and sent for bacterial culture after hospital day 2 and within 7 days of HAP diagnosis in 344 of these hospitalizations (29.4%), with a total of 478 sputum specimens, yielding 63 (13.2%) positive, 109 (22.8%) negative, and 306 (64.0%) contaminated cultures (>10 epithelial cells per high power fi eld). Signifi cant predictors of a positive sputum culture were chronic lung disease (relative risk [RR] = 2.0; 95% confi dence interval [CI], 1.2-3.4) and steroid use (RR = 1.8; 95% CI, 1.1-3.2). The most commonly identifi ed organisms were Gram-negative rods not further speciated (25.9%), Staphylococcus aureus (21.0%), and Pseudomonas aeruginosa (14.8%). Because of the ease of obtaining a sputum sample combined with the prevalence of commonly drug-resistant organisms, we suggest that sputum culture in HAP is a potentially useful noninvasive diagnostic technique.

Sputum bacteriology and clinical response to antibiotics in moderate exacerbation of chronic obstructive pulmonary disease

BACKGROUND

Presence of purulent sputum during an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is considered sufficient indication for starting empirical antibiotics. We investigated the relationship between detection of potentially pathogenic bacteria (PPB) using sputum culture or polymerase chain reaction (PCR) and clinical response and sought the risk factors for PPB growth.

METHODS

In 342 outpatients with AECOPD, we compared detection rates of H. influenzae (HI) and S. pneumoniae (SP) using conventional sputum culture versus PCR. The utility of either technique to predict clinical cure or failure after effective antibiotics was assessed. The factors predicting positive sputum cultures were evaluated using logistic regression.

RESULTS

Using sputum culture, 132 PPB were detected. The predominant bacteria were HI (40.9%) and SP (19.7%). Detection of HI or SP in sputum was higher using PCR than culture growth (60.8% vs 18.6%; P < .001). Clinical response was not affected by the results of either technique. Independent risk factors for PPB isolation were Gram-negative bacteria on sputum smear (OR 15.78, 95% CI 6.38-39.06; P < .001), sputum purulence (OR 2.31, 95% CI, 1.05-5.11; P = .04), body temperature (OR 0.16, 95% CI 0.05-0.54; P = .003), albumin level (OR 0.29, 95% CI 0.09-0.88; P = .03) and dyspnea grade (OR 0.51, 95% CI 0.27-0.96; P = .04).

CONCLUSIONS

Neither culture growth nor PCR positivity for HI or SP in sputum predicted clinical response to antibiotics; therefore, these tests are not necessary for outpatients with AECOPD. Examining Gram-staining and purulence on sputum smear, however, was significant to predict PPB growth in sputum.

Pilot implementation of a contact tracing intervention for tuberculosis case detection in Kisumu County, Kenya

Leveraging an existing community health strategy, a contact tracing intervention was piloted under routine programmatic conditions at three facilities in Kisumu County, Kenya. Data collected during a 6-month period were compared to existing programmatic data. After implementation of the intervention, we found enhanced programmatic contact tracing practices, noting an increase in the proportions of index cases traced, symptomatic contacts referred, referred contacts presenting to a facility for tuberculosis screening, and eligible contacts started on isoniazid preventive therapy. As contact tracing is scaled up, health ministries should consider the adoption of similar contact tracing interventions to improve contact tracing practices.

Early Biomarkers and Regulatory Innovation in Multidrug-Resistant Tuberculosis

Biomarkers play an essential role in accelerating drug development. Sputum culture conversion using solid medium is the best-characterized tuberculosis biomarker, having been examined at the patient and trial levels in studies with thousands of subjects, and having recently been validated using data from 3 unsuccessful phase 3 trials. We presently are poised at the threshold of regulatory innovation for antibacterials to treat drug-resistant infections, in which Special Medical Use authorization restricted to patients with limited options could be based on the results of small clinical trials. Patients worldwide would be well served by licensing of new regimens for multidrug-resistant tuberculosis based on biomarker evidence commensurate with the urgency of the current global crisis.

Understanding persistent bacterial lung infections: clinical implications informed by the biology of the microbiota and biofilms

The infections found in chronic obstructive pulmonary disease, cystic fibrosis, and bronchiectasis share a number of clinical similarities, the most striking of which is bacterial persistence despite the use of antibiotics. These infections have been clinically described using culture-based methods usually performed on sputum samples, and treatment has been directed towards the bacteria found in this manner. Unfortunately the clinical response to antibiotics is frequently not predictable based on these cultures, and the role of these cultured organisms in disease progression has been debated. The past 20 years have seen a revolution in the techniques used to describe bacterial populations and their growth patterns. These techniques have revealed these persistent lung infections are vastly more complicated than described by traditional, and still widely relied upon, sputum cultures. A better understanding of the initiation and evolution of these infections, and better clinical tools to describe them, will dramatically alter the way patients are cared for. While clinical tests to more accurately describe these infections are not yet available, the better appreciation of these infections afforded by current science should enlighten practitioners as to the care of their patients with these diseases.

Particulate matter is associated with sputum culture conversion in patients with culture-positive tuberculosis

Emerging risk factors for tuberculosis (TB) infection, such as air pollution, play a significant role at both the individual and population levels. However, the association between air pollution and TB remains unclear. The objective of this study was to examine the association between outdoor air pollution and sputum culture conversion in TB patients. In the present study, 389 subjects were recruited from a hospital in Taiwan from 2010 to 2012: 144 controls with non-TB-related pulmonary diseases with negative sputum cultures and 245 culture-positive TB subjects. We observed that a 1 μg/m³ increase in particulate matter of ≤10 μm in aerodynamic diameter (PM₁₀) resulted in 4% higher odds of TB (odds ratio =1.04, 95% confidence interval =1.01–1.08, P<0.05). The chest X-ray grading of TB subjects was correlated to 1 year levels of PM₁₀ (R²=0.94, P<0.05). However, there were no associations of pulmonary cavitation or treatment success rate with PM₁₀. In subjects with TB-positive cultures, annual exposure to ≥50 μg/m³ PM₁₀ was associated with an increase in the time required for sputum culture conversion (hazard ratio =1.28, 95% confidence interval: 1.07–1.84, P<0.05). In conclusion, chronic exposure to ≥50 μg/m³ PM₁₀ may prolong the sputum culture conversion of TB patients with sputum-positive cultures.

Bacterial flora in the sputum and comorbidity in patients with acute exacerbations of COPD

OBJECTIVE

To determine in patients admitted with an acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) the association between the isolation of potential pathogens in a conventional sputum culture and comorbidities.

PATIENTS AND METHODS

The ESMI study is a multicenter observational study. Patients with AE-COPD admitted to the Internal Medicine departments of 70 hospitals were included. The clinical characteristics, treatments, and comorbidities were gathered. The results of conventional sputum cultures were recorded.

RESULTS

A total of 536 patients were included, of which 161 produced valid sputum and a potentially pathogenic microorganism was isolated from 88 subjects (16.4%). The isolation of Pseudomonas aeruginosa (30.7%) was associated with a greater severity of the lung disease (previous admissions [P= 0.026], dyspnea scale [P=0.047], post-broncodilator forced expiratory volume in 1 second (FEV1) [P=0.005], and the BODEx index [P=0.009]); also with higher prevalence of cor pulmonale (P=0.017), heart failure (P=0.048), and cerebrovascular disease (P=0.026). Streptococcus pneumoniae (26.1%) was associated with more comorbidity according to number of diseases (P=0.018); notably, peripheral artery disease (P=0.033), hypertension (P=0.029), dyslipidemia (P=0.039), osteoporosis (P=0.0001), and depression (P=0.005).

CONCLUSION

Patients with AE-COPD and P. aeruginosa present higher severity of COPD, while those with S. pneumoniae present greater comorbidity. The potentially pathogenic microorganism obtained in the sputum culture depends on the associated comorbidities.

Comparison of serum procalcitonin in respiratory infections and bloodstream infections

PURPOSE

This study observed the relationship between procalcitonin (PCT) and results of sputum culture, the relationship between PCT and results of blood culture to evaluate and compare the value of PCT in respiratory and bloodstream infections.

METHODS

We analyzed 1616 patients in which PCT and sputum culture were concurrently ordered and analyzed, and 1096 patients in which PCT and blood culture were concurrently ordered and analyzed from January 2014 to May 2015. PCT concentrations were measured by on a Roche Cobas E601 ECL analyzer.

RESULTS

The average values of PCT from patients with sputum culture positive and negative were 0.42 (0.17-2.16) and 0.12 (0.06-0.57) ng/ml respectively, and the average values of PCT from patients with blood culture positive and negative were 9.54 (2.10-48.47) and 0.28 (0.10-1.23) ng/ml respectively. In sputum culture, positive rate of PCT in cases with growth of pathogens was 47.1%. In blood culture, positive rate of PCT in cases with growth of pathogens was 89.2%.

CONCLUSIONS

PCT is useful in early diagnosis of respiratory infections and bloodstream infections, but the specificity of PCT in diagnosing respiratory infections is not as high as it is in bloodstream infections.

Number of sputum specimens during treatment follow-up of tuberculosis patients: two or one?

SETTING

National Institute for Research in Tuberculosis clinics in Chennai and Madurai, India.

OBJECTIVE

To examine the pattern of serial smears (negative-negative [NN], negative-positive [NP], positive-negative [PN], positive-positive [PP]) during treatment follow-up of culture-confirmed new smear-positive tuberculosis (TB) patients, and the proportion of culture-negatives in each category.

DESIGN

We reviewed the records and extracted follow-up smear (fluorescent microscopy) and culture (Löwenstein-Jensen) results of patients enrolled in clinical trials from January 2000 to August 2012 and treated with the Category I regimen (2EHRZ3/4HR3). Data entry and analysis were performed using EpiData.

RESULTS

Among 520 patients (176 infected with the human immunodeficiency virus), the proportions of culture-negative patients with NN, discordant (PN or NP) and PP patterns were approximately 98%, 80% and 40%, respectively. The smear-positive culture-negative phenomenon was more frequent in follow-up smear results graded 1+, followed by 2+ and 3+.

CONCLUSION

There is justification for discontinuing the examination of second specimens during treatment follow-up among TB patients. However, a positive result on the first smear needs to be confirmed by a second positive result before making clinical management decisions. The World Health Organization may need to reconsider its recommendation on this issue.

Tuberculosis and excess alcohol use in the United States, 1997-2012

BACKGROUND

Excess alcohol use among tuberculosis (TB) patients complicates TB control strategies.

OBJECTIVES

To characterize the role of excess alcohol use in TB control, we describe the epidemiology of excess alcohol use and TB in the United States among those aged ⩾15 years.

DESIGN

Using data reported to the National Tuberculosis Surveillance System, 1997-2012, we examined associations between excess alcohol use and TB treatment outcomes and markers for increased transmission (involvement in a local genotype cluster of cases) using multivariate logistic regression. We used Cox proportional hazards regression analysis to examine the relationship between excess alcohol use and the rate of conversion from positive to negative in sputum culture results.

RESULTS

Excess alcohol use was documented for 31 207 (15.1%) of 207 307 patients. Prevalence of excess alcohol use was greater among male patients (20.6%) and US-born patients (24.6%). Excess alcohol use was associated with a positive sputum smear result (aOR 1.23, 95%CI 1.18-1.28) and death during treatment (vs. completion of treatment) (aOR 1.16, 95%CI 1.10-1.22). The rate of culture conversion was higher among patients without excess alcohol use (adjusted hazard ratio 1.20, 95%CI 1.18-1.23).

CONCLUSIONS

Excess alcohol use was common among patients with TB, and was associated with TB transmission, lower rates of sputum culture conversion, and greater mortality.

Isolation of Mycobacterium fortuitum in sputum specimens of a patient with chronic cough: Is it clinically significant?

Managing chronic cough is diagnostically challenging especially in primary care. This case report highlights the difficulties experienced in approaching a case of chronic cough from a primary care perspective. The discussion also involves the clinical significance and treatment dilemma of M. fortuitum chelonae complex that was isolated from the sputum cultures of an elderly woman who presented with chronic cough for more than a year.

The pyrazinamide susceptibility breakpoint above which combination therapy fails

Objectives

To identify the pyrazinamide MIC above which standard combination therapy fails.

Methods

MICs of pyrazinamide were determined for Mycobacterium tuberculosis isolates, cultured from 58 patients in a previous randomized clinical trial in Cape Town, South Africa. The MICs were determined using BACTEC MGIT 960 for isolates that were collected before standard treatment with isoniazid, rifampicin, pyrazinamide and ethambutol commenced. Weekly sputum collections were subsequently made for 8 weeks in order to culture M. tuberculosis in Middlebrook broth medium. Classification and regression tree (CART) analysis was utilized to identify the pyrazinamide MIC predictive of sputum culture results at the end of pyrazinamide therapy. The machine learning-derived susceptibility breakpoints were then confirmed using standard association statistics that took into account confounders of 2 month sputum conversion.

Results

The pyrazinamide MIC range was 12.5 to >100 mg/L for the isolates prior to therapy. The epidemiological 95% cut-off value was >100 mg/L. The 2 month sputum conversion rate in liquid cultures was 26% by stringent criteria and 48% by less stringent criteria. CART analysis identified an MIC breakpoint of 50 mg/L, above which patients had poor sputum conversion rates. The relative risk of poor sputum conversion was 1.5 (95% CI: 1.2–1.8) for an MIC >50 mg/L compared with an MIC ≤50 mg/L.

Conclusions

We propose a pyrazinamide susceptibility breakpoint of 50 mg/L for clinical decision making and for development of rapid susceptibility assays. This breakpoint is identical to that identified using computer-aided simulations of hollow fibre system output.

Clinical analysis of pulmonary infection in hemodialysis patients

The present study aimed to investigate the pathogen distribution and drug resistance of lung infections in hemodialysis to guide clinical empirical pharmacy. The clinical data of 116 hemodialysis patients with pulmonary infection were analyzed. The majority of the 82 pathogens isolated from the sputa of patients were Gram-negative bacteria (accounting for 71.95%). The results of the drug sensitivity test suggested that Gram-negative bacilli had low resistance rates to piperacillin and tazobactam, imipenem and amikacin, while Gram-positive cocci had a low resistance rate to vancomycin. All resistance rates of the pathogens to other common antimicrobials were >50%. The pathogens resulting in lung infections in hemodialysis patients were mainly Gram-negative bacteria and were significantly resistant to various antibacterials. Results of the this study demonstrate that pathological examination should be performed as early as possible and effective antimicrobial agents should be chosen according to drug sensitivity test results.

Bacteriological and clinical profile of Community acquired pneumonia in hospitalized patients

The aim of our study was to obtain comprehensive insight into the bacteriological and clinical profile of community-acquired pneumonia requiring hospitalization. The patient population consisted of 100 patients admitted with the diagnosis of community-acquired pneumonia (CAP), as defined by British Thoracic society, from December 1998 to Dec 2000, at the Sher- i-Kashmir institute of Medical Sciences Soura, Srinagar, India. Gram negative organisms were the commonest cause (19/29), followed by gram positive (10/29). In 71 cases no etiological cause was obtained. Pseudomonas aeruginosa was the commonest pathogen (10/29), followed by Staphylococcus aureus (7/29), Escherichia coli (6/29), Klebsiella spp. (3/29), Streptococcus pyogenes (1/29), Streptococcus pneumoniae (1/29) and Acinetobacter spp. (1/29). Sputum was the most common etiological source of organism isolation (26) followed by blood (6), pleural fluid (3), and pus culture (1). Maximum number of patients presented with cough (99%), fever (95%), tachycardia (92%), pleuritic chest pain (75%), sputum production (65%) and leucocytosis (43%). The commonest predisposing factors were smoking (65%), COPD (57%), structural lung disease (21%), diabetes mellitus (13%), and decreased level of consciousness following seizure (eight per cent) and chronic alcoholism (one per cent). Fourteen patients, of whom, nine were males and five females, died. Staphylococcus aureus was the causative organism in four, Pseudomonas in two, Klebsiella in one, and no organism was isolated in seven cases. The factors predicting mortality at admission were - age over 62 years, history of COPD or smoking, hypotension, altered sensorium, respiratory failure, leucocytosis, and staphylococcus pneumonia and undetermined etiology. The overall rate of identification of microbial etiology of community-acquired pneumonia was 29%, which is very low, and if serological tests for legionella, mycoplasma and viruses are performed the diagnostic yield would definitely be better. This emphasizes the need for further studies (including the serological tests for Legionella, mycoplasma and viruses) to identify the microbial etiology of CAP.

Pulmonary exacerbations in cystic fibrosis with negative bacterial cultures

BACKGROUND

Pulmonary exacerbations are a major cause of morbidity in cystic fibrosis (CF) and likely contribute to lung function decline. Exacerbations are often associated with characteristic airway bacteria [CF related bacteria (CFRB)]. However, some patients do not have CFRB detected by culture during exacerbations.

OBJECTIVES

We sought to determine the proportion of airway cultures negative for CFRB during pulmonary exacerbations, and to characterize patients who were CFRB-negative versus CFRB-positive.

METHODS

We performed a retrospective study of patients with CF admitted for a pulmonary exacerbation. Patients were classified as CFRB-positive or CFRB-negative based on admission airway cultures. Demographics, clinical presentation, lung function, history of chronic Pseudomonas aeruginosa infection and improvement in lung function with treatment were compared between groups.

MAIN RESULTS

There were 672 admissions for exacerbation involving 211 patients over 5 years. Seventeen percent were classified as CFRB-negative. Forty-one percent of bronchoalveolar lavage (BAL), 32% of throat and 10% of sputum samples were CFRB-negative. Among patients capable of expectorating sputum, the CFRB-negative group was younger, less likely to have chronic P. aeruginosa, had higher lung function and body mass index (BMI), and had a lower systemic inflammatory response on admission compared to those with CFRB-positive cultures. The two groups had similar numbers of patients with three or more signs and symptoms of a pulmonary exacerbation (88% vs. 92%). Both groups returned to baseline lung function following treatment.

CONCLUSIONS

A significant number of patients with CF and pulmonary exacerbation did not have typical CFRB detected by culture. Patients without CFRB still had characteristic signs and symptoms of pulmonary exacerbation and responded to treatment. Understanding the causes of illness in these patients may improve the diagnosis and treatment of pulmonary exacerbations in CF.