Comparison of six different criteria for judging the acceptability of sputum specimens

Practical Guidance for Clinical Microbiology Laboratories: Updated guidance for processing respiratory tract samples from people with cystic fibrosis

SUMMARYThis guidance presents recommendations for clinical microbiology laboratories for processing respiratory samples from people with cystic fibrosis (pwCF). Appropriate processing of respiratory samples is crucial to detect bacterial and fungal pathogens, guide treatment, monitor the epidemiology of cystic fibrosis (CF) pathogens, and assess therapeutic interventions. Thanks to CF transmembrane conductance regulator modulator therapy, the health of pwCF has improved, but as a result, fewer pwCF spontaneously expectorate sputum. Thus, the collection of sputum samples has decreased, while the collection of other types of respiratory samples such as oropharyngeal and bronchoalveolar lavage samples has increased. To optimize the detection of microorganisms, including Pseudomonas aeruginosa, Staphylococcus aureus, Haemophilus influenzae, and Burkholderia cepacia complex; other less common non-lactose fermenting Gram-negative bacilli, e.g., Stenotrophomonas maltophilia, Inquilinus, Achromobacter, Ralstonia, and Pandoraea species; and yeasts and filamentous fungi, non-selective and selective culture media are recommended for all types of respiratory samples, including samples obtained from pwCF after lung transplantation. There are no consensus recommendations for laboratory practices to detect, characterize, and report small colony variants (SCVs) of S. aureus, although studies are ongoing to address the potential clinical impact of SCVs. Accurate identification of less common Gram-negative bacilli, e.g., S. maltophilia, Inquilinus, Achromobacter, Ralstonia, and Pandoraea species, as well as yeasts and filamentous fungi, is recommended to understand their epidemiology and clinical importance in pwCF. However, conventional biochemical tests and automated platforms may not accurately identify CF pathogens. MALDI-TOF MS provides excellent genus-level identification, but databases may lack representation of CF pathogens to the species-level. Thus, DNA sequence analysis should be routinely available to laboratories for selected clinical circumstances. Antimicrobial susceptibility testing (AST) is not recommended for every routine surveillance culture obtained from pwCF, although selective AST may be helpful, e.g., for unusual pathogens or exacerbations unresponsive to initial therapy. While this guidance reflects current care paradigms for pwCF, recommendations will continue to evolve as CF research expands the evidence base for laboratory practices.

New methods to detect bacterial or viral infections in patients with chronic obstructive pulmonary disease

INTRODUCTION

Patients with chronic obstructive pulmonary disease (COPD) are frequently colonized and infected by respiratory pathogens. Identifying these infectious etiologies is critical for understanding the microbial dynamics of COPD and for the appropriate use of antimicrobials during exacerbations.

AREAS COVERED

Traditional methods, such as bacterial and viral cultures, have been standard in diagnosing respiratory infections. However, these methods have significant limitations, including lack of sensitivity and prolonged turnaround time. Modern molecular approaches offer rapid, sensitive, and specific detection, though they also come with their own challenges. This review explores and evaluates the clinical utility of the latest advancements in detecting bacterial and viral respiratory infections in COPD, encompassing molecular techniques, biomarkers, and emerging technologies.

EXPERT OPINION

In the evolving landscape of COPD management, integrating molecular diagnostics and emerging technologies holds great promise. The enhanced sensitivity of molecular techniques has significantly advanced our understanding of the role of microbes in COPD. However, many of these technologies have primarily been developed for pneumonia diagnosis or research applications, and their clinical utility in managing COPD requires further evaluation.

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.

The diagnostic utility of microscopic quality assessment of sputum samples in the era of rapid syndromic PCR testing

This prospective study assessed the value of initial microscopy evaluation of sputum samples submitted for rapid syndromic PCR-based testing. Bacterial detections by the BioFire FilmArray Pneumonia Panel plus in 126 high- and 108 low-quality sputum samples, based on initial microscopy evaluation in samples from patients with lower respiratory tract infections were compared. We found that high-quality samples had a higher proportion of bacterial detections compared to low-quality samples (P = 0.013). This included a higher proportion of detections of bacteria deemed clinically relevant by predefined criteria (70% and 55%, P = 0.016), as well as a higher proportion of detections of Haemophilus influenzae (36% and 20%, P = 0.010). High-quality samples also had more detections of bacteria with high semi-quantitative values. The study found no significant difference between high- and low-quality samples in the proportions of samples with a single species of bacteria detected, samples with a bacteria treated by the clinician, samples with detection of a proven etiology of community-acquired pneumonia by predefined criteria, the number of bacterial species detected, or the detection of Streptococcus pneumoniae, Moraxella catarrhalis, or Staphylococcus aureus. The results showed that 40% (95% CI 35%-47%) of the bacterial detections would have been missed if only high-quality samples were analyzed. This included 41% (27%-56%) of detections of S. pneumoniae, 33% (23%-45%) of detections of H. influenzae, 42% (28%-58%) of detections of S. aureus, and 37% (23%-54%) of detections of M. catarrhalis. These findings suggest that all sputum samples submitted for rapid syndromic PCR testing should be analyzed, regardless of initial microscopy quality assessment. (This study has been registered at ClinicalTrials.gov under registration no. NCT04660084.) IMPORTANCE Microscopic quality assessment of sputum samples was originally designed for sputum culture, and its applicability in today's workflow, which includes syndromic PCR testing, may differ. Addressing this crucial gap, our study emphasizes the need to optimize the use and workflow of syndromic PCR panels, like the BioFire FilmArray Pneumonia plus (FAP plus), in microbiology laboratories. These advanced PCR-based tests offer rapid and comprehensive pathogen detection for respiratory infections, yet their full potential remains uncertain. By comparing bacterial detections in high- and low-quality sputum samples, we underscore the importance of including low-quality samples in testing. Our findings reveal a significant proportion of potentially clinically relevant bacterial detections that would have been missed if only high-quality samples were analyzed. These insights support the efficient implementation of syndromic PCR panels, ultimately enhancing patient care and outcomes.

Candida Spp. in Lower Respiratory Tract Secretions - A Ten Years Retrospective Study

Introduction

Lower respiratory tract secretions (LRTS) like sputum and tracheal aspirates are frequently sent to the microbiology laboratory from patients with various respiratory pathologies. Improper collection techniques can lead to false-positive results, resulting in improper therapy.

Aim of the study

To determine the percentage of contaminated samples sent to the microbiology laboratory, to establish the prevalence of Candida spp. in non-contaminated samples and therefore, the presence of Candida spp. originating in lower respiratory tract infections. Material and

Methods

A 10-year data survey was conducted to assess the differences in Candida prevalence from contaminated versus non-contaminated samples, assessed and categorised by Bartlett grading system, and to emphasise the importance of quality control for potentially contaminated samples. The data were analysed according to gender, age, referring departments, and the species of Candida. For the statistical analysis, Kruskal-Wallis and Fisher tests were used, and the alpha value was set for 0.5.

Results

The prevalence of Candida spp. in all analysed samples was 31.60%. After excluding the contaminated samples, the actual prevalence was 27.66%. Of all sputum samples, 31.6% were contaminated. Patients aged more than 40 years old were more prone to provide contaminated sputum samples. C. albicans is more prevalent in non-contaminated sputum samples. In both sputum and tracheal aspirates, the chances of identifying a single species are higher than the chances of identifying multiple species.

Conclusions

The study emphasises the importance of assessing the quality of sputum samples because of the high number of improperly collected samples sent to the microbiology laboratory.

The Sputum Microbiome in Pulmonary Tuberculosis and Its Association With Disease Manifestations: A Cross-Sectional Study

Each day, approximately 27,000 people become ill with tuberculosis (TB), and 4,000 die from this disease. Pulmonary TB is the main clinical form of TB, and affects the lungs with a considerably heterogeneous manifestation among patients. Immunomodulation by an interplay of host-, environment-, and pathogen-associated factors partially explains such heterogeneity. Microbial communities residing in the host's airways have immunomodulatory effects, but it is unclear if the inter-individual variability of these microbial communities is associated with the heterogeneity of pulmonary TB. Here, we investigated this possibility by characterizing the microbial composition in the sputum of 334 TB patients from Tanzania, and by assessing its association with three aspects of disease manifestations: sputum mycobacterial load, severe clinical findings, and chest x-ray (CXR) findings. Compositional data analysis of taxonomic profiles based on 16S-rRNA gene amplicon sequencing and on whole metagenome shotgun sequencing, and graph-based inference of microbial associations revealed that the airway microbiome of TB patients was shaped by inverse relationships between Streptococcus and two anaerobes: Selenomonas and Fusobacterium. Specifically, the strength of these microbial associations was negatively correlated with Faith's phylogenetic diversity (PD) and with the accumulation of transient genera. Furthermore, low body mass index (BMI) determined the association between abnormal CXRs and community diversity and composition. These associations were mediated by increased abundance of Selenomonas and Fusobacterium, relative to the abundance of Streptococcus, in underweight patients with lung parenchymal infiltrates and in comparison to those with normal chest x-rays. And last, the detection of herpesviruses and anelloviruses in sputum microbial assemblage was linked to co-infection with HIV. Given the anaerobic metabolism of Selenomonas and Fusobacterium, and the hypoxic environment of lung infiltrates, our results suggest that in underweight TB patients, lung tissue remodeling toward anaerobic conditions favors the growth of Selenomonas and Fusobacterium at the expense of Streptococcus. These new insights into the interplay among particular members of the airway microbiome, BMI, and lung parenchymal lesions in TB patients, add a new dimension to the long-known association between low BMI and pulmonary TB. Our results also drive attention to the airways virome in the context of HIV-TB coinfection.

An observational study of anaerobic bacteria in cystic fibrosis lung using culture dependant and independent approaches

Strict anaerobes are undeniably important residents of the cystic fibrosis (CF) lung but are still unknowns. The main objectives of this study were to describe anaerobic bacteria diversity in CF airway microbiota and to evaluate the association with lung function. An observational study was conducted during eight months. A hundred and one patients were enrolled in the study, and 150 sputum samples were collected using a sterile sample kit designed to preserve anaerobic conditions. An extended-culture approach on 112 sputa and a molecular approach (quantitative PCR targeting three of the main anaerobic genera in CF lung: Prevotella, Veillonella, and Fusobacterium) on 141 sputa were developed. On culture, 91.1% of sputa were positive for at least one anaerobic bacterial species, with an average of six anaerobic species detected per sputum. Thirty-one anaerobic genera and 69 species were found, which is the largest anaerobe diversity ever reported in CF lungs. Better lung function (defined as Forced Expiratory Volume in one second > 70%) was significantly associated with higher quantification of Veillonella. These results raise the question of the potential impact of anaerobes on lung function.

Nocardia Infections: Ten Years Experience from a Tertiary Health Care Center in North India (2007-2016)

BACKGROUND

Nocardia species are important cause of infections in humans but are underreported due to missed diagnosis as well as misdiagnosis. Majority of the literature on these infections consists of case reports or series with few articles describing high number of cases.

OBJECTIVE

To study the epidemiology of Nocardia infections in a tertiary care center.

MATERIALS AND METHODS

This retrospective observational study was done in a tertiary care centre of North India over a period of 10 years (2007-2016). The detection of Nocardia spp. from clinical specimens was done by conventional methods viz. direct microscopy (Gram's stain, modified Ziehl -Neelsen stain [1%], KOH examination) and culture.

RESULTS

A total of 25 cases of nocardiosis were diagnosed during the study period. The mean age of the patients was 50.9 years (range 30-72 years) with a male:female ratio of 3:2. The site of disease in these patients included pulmonary (n=18), cutaneous (n=4), perinephric abscess (n=1), ocular (n=1) and bone (n=1). Risk factors associated were underlying lung disease (n=11), smoking (n=7), diabetes (n=5) and steroid therapy (n=4) in pulmonary nocardiosis, iatrogenic (n=1) and leprosy (n=1) in cutaneous nocardiosis, diabetes in perinephric abscess and cataract surgery in ocular nocardiosis. Culture was positive in 12/25 (48%) patients for Nocardia spp. Direct microscopy was positive in 22 patients. We wish to highlight that meticulous observation of KOH wet mount examination helped in clinching the diagnosis of Nocardiosis in 3 cases which were earlier missed by other methods.

CONCLUSION

Good communication with the clinician alongside a meticulous effort in the laboratory is essential for appropriate diagnosis and management of these cases.

Evaluation of semi-quantitative compared to quantitative cultures of tracheal aspirates for the yield of culturable respiratory pathogens - a cross-sectional study

Background

Diagnosis of lower respiratory tract infections (LRTI) depends on the presence of clinical, radiological and microbiological findings. Endotracheal suction aspirate (ETSA) is the commonest respiratory sample sent for culture from intubated patients. Very few studies have compared quantitative and semi-quantitative processing of ETSA cultures for LRTI diagnosis. We determined the diagnostic accuracy of quantitative and semi-quantitative ETSA culture for LRTI diagnosis, agreement between the quantitative and semi quantitative culture techniques and the yield of respiratory pathogens with both methods.

Methods

This was a cross-sectional study conducted at the Aga Khan University clinical laboratory, Karachi, Pakistan. One hundred and seventy-eight ETSA samples sent for routine bacteriological cultures were processed quantitatively as part of regular specimen processing method and semi-quantitatively. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy was calculated for both methods using clinical diagnosis of pneumonia as reference standard. Agreement between the quantitative and semi quantitative methods was assessed via the kappa statistic test. Pathogen yield between the two methods was compared using Pearson’s chi-square test.

Results

The quantitative and semi-quantitative methods yielded pathogens in 81 (45.5%) and 85 (47.8%) cases respectively. There was complete concordance of both techniques in 155 (87.1%) ETSA samples. No growth was observed in 45 (25.3%) ETSA specimens with quantitative culture and 37 (20.8%) cases by semi-quantitative culture. The diagnostic accuracy of both techniques were comparable; 64.6% for quantitative and 64.0% for semi-quantitative culture. The kappa agreement was found to be 0.84 (95% CI, 0.77–0.91) representing almost perfect agreement between the two methods. Although semi-quantitative cultures yielded more pathogens (47.8%) as compared to quantitative ETSA cultures (45.5%), the difference was only 2.3%. However, this difference achieved statistical (chi-square p-value < 0.001) favoring semi-quantitative culture methods over quantitative culture techniques for processing ETSA.

Conclusion

In conclusion, there is a strong agreement between the performances of both methods of processing ETSA cultures in terms of accuracy of LRTI diagnosis. Semi-quantitative cultures of ETSA yielded more pathogens as compared to quantitative cultures. Although both techniques were comparable, we recommend processing of ETSA using semi-quantitative technique due to its ease and reduced processing time.

Sputum versus nasopharyngeal samples for the molecular diagnosis of respiratory viral infection in cystic fibrosis: A pilot study

Viruses are important agents in lung function deterioration in Cystic Fibrosis (CF). To date, no standard operating procedures (SOPs) have been established to determine which sampling method is the most effective for an optimal virological diagnosis of respiratory viral infections in CF. Here we investigated the performances of two sampling sites, sputum samples versus nasopharyngeal (NP) swabs, for thirty participants from three CF centres presenting an acute respiratory infection. Sputum and NP samples were simultaneously collected and multiplex PCR targeting 16 to 18 viruses were performed. Viruses were detected for 18/30 patients (60%). A high concordance between the sputum and NP samples was observed in 25 (83%) paired samples of which 13 tested positive and 12 tested negative. These results highlighted the relevance of sputum sampling for diagnostic of respiratory viruses in CF, which is less invasive and better accepted by CF patients than NP, and allows accurate bacterial detection.

Utilidad de los criterios de Murray para el procesamiento de esputo en pacientes con fibrosis quística. Laboratorio de Infectados de la Universidad de Antioquia (Medellín/Colombia)

Introducción: la fibrosis quística (FQ) es una enfermedad autosómica recesiva que aumenta la viscosidad de las secreciones, en especial las del árbol respiratorio; genera inflamación crónica y colonización/infección por microorganismos, conduciendo a deterioro de la función pulmonar y muerte. Nuestro estudio evaluó la calidad del esputo de pacientes con FQ que ingresaron al Laboratorio de Infectados de la UdeA con base a los criterios de Murray. Metodología: estudio descriptivo con información retrospectiva, incluyendo todos los esputos de pacientes con FQ, recolectados entre enero de 2015 a diciembre de 2018. Resultados: se analizaron 686 muestras de 85 pacientes, de las cuáles se obtuvo cultivo positivo en 501 (73 %) y el 21 % no cumplían los criterios de calidad según Murray. De 908 aislamientos identificados, 823 (90.6 %) corresponden a microorganismos considerados como patógenos en la vía aérea de los pacientes con FQ donde se incluyen S aureus, Pseudomonas spp, H influenzae, Burkhordelia spp, A. xylosoxidans, S maltophilia, A fumigatus, entre otras. Conclusiones: los criterios de Murray no se deben utilizar para definir el procesamiento o no del esputo en pacientes con FQ.

Intrinsic and extrinsic factors associated with sputum characteristics of presumed tuberculosis patients

BACKGROUND

Sputum remains the most preferred specimen for detection of Mycobacterium tuberculosis due to its non-invasive method of production. Good quality sputum specimen is essential for accurate diagnosis of pulmonary tuberculosis (PTB). It is therefore imperative to assess factors that are related to the production of sputum that is of the best quality.

OBJECTIVE

We assessed the intrinsic and extrinsic characteristics of presumed tuberculosis patients and the quality of sputum they produced.

METHODS

This was a cross-sectional study in which consenting enrolled presumed tuberculosis patients were subjected to medical examination and a structured questionnaire administered to collect clinical history, demographic information, environmental and behavioral characteristics. The enrolled participants were instructed on how to collect spot and morning sputum specimens for macroscopic and microscopic assessment to determine any association.

RESULTS

A total of 309 patients were enrolled into the study with an even distribution on gender (50.5% males). Of these, 202 (65.3%) submitted both a spot and a morning specimen for analysis. On macroscopic examination, 70% spot and 68% morning sputum were characterized as good quality (Purulent/mucoid). The factors associated (p<0.05) with quality specimen included both intrinsic and extrinsic factors. The intrinsic factors included: difficulty in breathing, presence of conjunctivitis and knowledge of the disease whereas the only extrinsic factor associated with production of good quality sputum for tuberculosis diagnosis was time taken by patient to seek tuberculosis treatment after occurrence of any of the TB symptoms.

CONCLUSION

Both intrinsic and extrinsic factors affected the quality of sputum produced by presumed tuberculosis patients. Clinical and behavioral characteristics including conjunctivitis, difficulty in breathing and delay in seeking treatment were important factors that determined the production of good quality sputum specimens, while knowledge of tuberculosis disease did not compel presumed tuberculosis patients to produce good quality sputum for diagnosis of the disease.

Can sputum gram stain be used to predict lower respiratory tract infection and guide empiric antimicrobial treatment: Experience from a tertiary care hospital

BACKGROUND

The mortality associated with lower respiratory tract infection is high. Indiscriminate use of antimicrobials leads to alteration of respiratory tract flora and development of multi-drug resistance. Rapid diagnostic tests to confirm infection can guide the clinicians about antimicrobial treatment. So the present study was planned to evaluate the role of direct gram stain examination as a rapid and simple test to help clinicians for appropriate patient management.

METHODS

The present study was conducted on 1000 respiratory specimens which were processed using conventional microbiological techniques. Gram stain smear and culture results were compared statistically to assess the sensitivity, specificity, positive and negative predictive value. The agreement between gram stain smear examination and culture was calculated using kappa statistics.

RESULTS

Potential pathogens were obtained from 28 of 209 deeply coughed out sputum samples (13.3%) and from 19 of 315 saliva mixed sputum samples (6%). Out of 473 tracheal aspirates, 115 (24.3%) had potential pathogens. The sensitivity for predicting infection was higher for good quality sputum samples (54%) as compared to poor quality sputum samples (37%). The gram stain and culture of tracheal samples had a good agreement for predicting infection whereas there was only moderate agreement for sputum sample.

CONCLUSION

Gram stain smear examination from respiratory samples can be used to guide empiric antibiotic therapy pending final culture sensitivity results if the attending physicians ensure appropriate sample collection and transport. In absence of these supportive measures smear examination should not be relied upon for empiric treatment.

Clinical Utility of Procalcitonin in the Diagnosis of Pneumonia

BACKGROUND

The clinical utility of procalcitonin in the diagnosis and management of pneumonia remains controversial.

METHODS

We assessed the clinical utility of procalcitonin in 2 prospective studies: first, a multicenter diagnostic study in patients presenting to the emergency department with acute dyspnea to directly compare the diagnostic accuracy of procalcitonin with that of interleukin 6 and C-reactive protein (CRP) in the diagnosis of pneumonia; second, a randomized management study of procalcitonin guidance in patients with acute heart failure and suspected pneumonia. Diagnostic accuracy for pneumonia as centrally adjudicated by 2 independent experts was quantified with the area under the ROC curve (AUC).

RESULTS

Among 690 patients in the diagnostic study, 178 (25.8%) had an adjudicated final diagnosis of pneumonia. Procalcitonin, interleukin 6, and CRP were significantly higher in patients with pneumonia than in those without. When compared to procalcitonin (AUC = 0.75; 95% CI, 0.71-0.78), interleukin 6 (AUC = 0.80; 95% CI, 0.77-0.83) and CRP (AUC = 0.82; 95% CI, 0.79-0.85) had significantly higher diagnostic accuracy (P = 0.010 and P < 0.001, respectively). The management study was stopped early owing to the unexpectedly low AUC of procalcitonin in the diagnostic study. Among 45 randomized patients, the number of days on antibiotic therapy and the length of hospital stay were similar (both P = 0.39) in patients randomized to the procalcitonin-guided group (n = 25) and usual-care group (n = 20).

CONCLUSIONS

In patients presenting with dyspnea, diagnostic accuracy of procalcitonin for pneumonia is only moderate and lower than that of interleukin 6 and CRP. The clinical utility of procalcitonin was lower than expected.

SUMMARY

Pneumonia has diverse and often unspecific symptoms. As the role of biomarkers in the diagnosis of pneumonia remains controversial, it is often difficult to distinguish pneumonia from other illnesses causing shortness of breath. The current study prospectively enrolled unselected patients presenting with acute dyspnea and directly compared the diagnostic accuracy of procalcitonin, interleukin 6, and CRP for the diagnosis of pneumonia. In this setting, diagnostic accuracy of procalcitonin for pneumonia was lower as compared to interleukin 6 and CRP. The clinical utility of procalcitonin was lower than expected.

CLINICALTRIALSGOV IDENTIFIER

NCT01831115.

Sputum Quality Assessment Regarding Sputum Culture for Diagnosing Lower Respiratory Tract Infections in Children

BACKGROUND

The clinical relevance of specimens from the lower airways is often debatable. However, they are most commonly examined for diagnosing lower respiratory tract infections (LRTIs).

AIM

This study aimed to determine the diagnostic value of sputum quality assessment about sputum culture for diagnosing LRTIs in children.

METHODS

In six months, a total of 1485 sputum samples were quality assessed by using Bartlett's grading system. All samples, regardless of their quality, were cultured, identified, and antimicrobial susceptibility testing was performed by Kirby-Bauer disc-diffusion method.

RESULTS

Among the acceptable category, defined by Bartlett's grading system, 132 (63.2%) samples showed culture positivity of which Streptococcus pneumoniae 48 (36.4%) was most commonly isolated, followed by Moraxella catarrhalis 22 (16.7%) and Haemophilus influenza 21 (15.9%). Among the non-acceptable category, 185 (14.5%) samples were culture positive of which most commonly isolated were Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa with 64 (34.6%), 54 (29.2%) and 28 (15.1%), respectively.

CONCLUSION

Sputum quality assessment is a useful tool for distinguishing the true respiratory pathogens from possible colonising flora for which antibiotic treatment should not be highly considered.

The Quality of Sputum Specimens as a Predictor of Isolated Bacteria From Patients With Lower Respiratory Tract Infections at a Tertiary Referral Hospital, Denpasar, Bali-Indonesia

Sputum quality is crucial in finding infectious bacteria that will be used to guide definitive antibiotic therapy. Errors in reporting isolated bacteria will affect the rate of patients' morbidity, mortality, and increase patient care costs. This study aims to find out the relationship between sputum quality and isolated bacteria at a Tertiary Referral Hospital, Denpasar, Bali-Indonesia. The study was conducted for 6 months in the Sanglah Hospital Clinical Microbiology laboratory. There were 726 sputum specimens examined and categorized based on Murray Washington criteria. After Gram examination, all specimens were inoculated on aerobic culture media. We classified 41.4% of poor-quality sputum specimens, and non-pathogenic bacteria were isolated from 70.2% of that specimen dominated by Streptococcus mitis (42.53%). Whereas, isolated pathogens were obtained from 54.4% of good-quality sputum specimens dominated by Klebsiella pneumonia (30.86%). Statistical analyses showed that there is a relationship between isolated bacteria and the sputum quality (OR = 3.844; p < 0.001). Good-quality sputum is 3.8 times more likely to isolate pathogenic bacteria than poor-quality sputum. In the Pearson Chi-Square test, the likelihood of isolating pathogenic bacteria from good-quality specimens was significant too (p < 0.001). The results of this study indicate that poor-quality sputum specimens are still found. Therefore, the capacity of good sputum collection must be improved. Supervision of the application of standard sputum culture operational procedures must be more rigorously carried out.

Harmonization of microbiology processes and standards: work in progress

Clinical microbiology is a highly challenging technical discipline, which makes it difficult to harmonize processes and protocols. In addition, the lack of scientific consensus on some diagnostic algorithms and the need to address the diverse needs of different patient populations contribute to the lack of interlaboratory consistency. Laboratories utilize a number of measures and metrics, but the lack of standardized approaches and data collection means that they cannot effectively evaluate their performance against their peers. Coordinated efforts are required to develop tools that can be used across laboratories regardless of size or complexity.

Monitoring sputum culture in resected esophageal cancer patients with preoperative treatment

Pneumonia is a major cause of postesophagectomy mortality and worsens the long-term survival in resected esophageal cancer patients. Moreover, preoperative treatments such as chemotherapy or chemoradiotherapy (which have recently been applied worldwide) might affect the bacterial flora of the sputum. To investigate the association among preoperative treatments, the bacterial flora of sputum, and the clinical and pathological features in resected esophageal cancer patients, this study newly investigates the effect of preoperative treatments on the bacterial flora of sputum. We investigated the association among preoperative treatments, the bacterial flora of sputum, and clinical and pathological features in 163 resected esophageal cancer patients within a single institution. Pathogenic bacteria such as Candida (14.1%), Staphylococcus aureus (6.7%), Enterobacter cloacae (6.1%), Haemophilus parainfluenzae (4.9%), Klebisiella pneumoniae (3.7%), Methicillin-resistant Staphylococcus aureus (MRSA) (3.7%), Pseudomonas aeruginosa (2.5%), Escherichia coli (1.8%), Streptococcus pneumoniae (1.8%), and Haemophilus influenzae (1.2%) were found in the sputum. The pathogen detection rate in the present study was 34.3% (56/163). In patients with preoperative chemotherapy and chemoradiotherapy, the indigenous Neisseria and Streptococcus species were significantly decreased (P= 0.04 and P= 0.04). However, the detection rates of pathogenic bacteria were not associated with preoperative treatments (all P> 0.07). There was not a significant difference of hospital stay between the sputum-monitored patients and unmonitored patients (35.5 vs. 49.9 days; P= 0.08). Patients undergoing preoperative treatments exhibited a significant decrease of indigenous bacteria, indicating that the treatment altered the bacterial flora of their sputum. This finding needs to be confirmed in large-scale independent studies or well-designed multicenter studies.

The Role of the Laboratory in Control of Nosocomial Infection

Nosocomial (hospital-associated) infection continues to represent a major problem for hospitals. Gram-negative aerobic bacilli continue to be identified most frequently as etiologic agents, but a number of new pathogens now are recognized to play a role. The persons responsible for infection control efforts and in charge of the clinical microbiology laboratory (frequently the same person) must cooperate closely to attack this problem. The role of the laboratory in attempts to minimize occurrence of nosocomial infection involves six aspects: 1) accurate identification of responsible organisms, 2) timely reporting of laboratory data, 3) provision of additional studies, when necessary, to establish similarity or difference of organisms, 4) provision, on occasion, of microbiologic studies of the hospital environment, 5) training of infection control personnel, and 6) participation in activities of the hospital infection control committee.

Direct sampling of cystic fibrosis lungs indicates that DNA-based analyses of upper-airway specimens can misrepresent lung microbiota

Recent work using culture-independent methods suggests that the lungs of cystic fibrosis (CF) patients harbor a vast array of bacteria not conventionally implicated in CF lung disease. However, sampling lung secretions in living subjects requires that expectorated specimens or collection devices pass through the oropharynx. Thus, contamination could confound results. Here, we compared culture-independent analyses of throat and sputum specimens to samples directly obtained from the lungs at the time of transplantation. We found that CF lungs with advanced disease contained relatively homogenous populations of typical CF pathogens. In contrast, upper-airway specimens from the same subjects contained higher levels of microbial diversity and organisms not typically considered CF pathogens. Furthermore, sputum exhibited day-to-day variation in the abundance of nontypical organisms, even in the absence of clinical changes. These findings suggest that oropharyngeal contamination could limit the accuracy of DNA-based measurements on upper-airway specimens. This work highlights the importance of sampling procedures for microbiome studies and suggests that methods that account for contamination are needed when DNA-based methods are used on clinical specimens.

Procedures for collection of induced sputum specimens from children

In most settings, sputum is not routinely collected for microbiological diagnosis from children with lower respiratory disease. To evaluate whether it is feasible and diagnostically useful to collect sputum in the Pneumonia Etiology Research for Child Health (PERCH) study, we reviewed the literature on induced sputum procedures. Protocols for induced sputum in children were collated from published reports and experts on respiratory disease and reviewed by an external advisory group for recommendation in the PERCH study. The advisory group compared 6 protocols: 4 followed a nebulization technique using hypertonic saline, and 2 followed a chest or abdomen massage technique. Grading systems for specimen quality were evaluated. Collecting sputum from children with lower respiratory tract illness is feasible and is performed around the world. An external advisory group recommended that sputum be collected from children hospitalized with severe and very severe pneumonia who participate in the PERCH study provided no contraindications exist. PERCH selected the nebulization technique using hypertonic saline.

Judging respiratory specimen acceptability for AFB microscopy: visual vs. microscopic screening

OBJECTIVES

To investigate whether visual assessment or microscopic grading of the cellular composition of specimens is a better strategy to screen specimen quality for tuberculosis (TB) diagnosis.

METHODS

About 2643 specimens were collected from TB suspects at the Federal TB centre in Pakistan. Specimens were classified as sputum or saliva visually and microscopically using the criteria proposed by McCarter and Robinson, Van Scoy, Geckler et al., Murray and Washington and Bartlett. The acid-fast bacilli (AFB)-positivity of specimens was also assessed. Results Despite being the least 'technical' and time consuming, visual assessment rejected the lowest proportion of AFB-positive specimens (0.3%). Most microscopic grading criteria, particularly those that considered the squamous epithelial cell count, rejected a large proportion of specimens (30-66%), of which a sizeable fraction contained AFB (6-12%).

CONCLUSIONS

Our results indicate that visual assessment by trained technicians is more effective and suitable than microscopic grading for screening specimens for TB diagnosis. TB control resources could be better allocated to optimizing visual screening than investing in more 'strict' microscopic grading tools.

O muco traqueobrônquico humano mantido em temperatura ambiente e suas propriedades físico-químicas

OBJETIVO: Verificar a influência da permanência em temperatura ambiente na análise da transportabilidade por ação ciliar e por tosse e do ângulo de contato do muco traqueobrônquico. MÉTODOS: Foi coletado muco hialino de 30 indivíduos sem doença pulmonar, e purulento de vinte pacientes com bronquiectasia. As amostras foram analisadas logo após a coleta e novamente após 24 h. RESULTADOS: Para o muco purulento, após 24 h em temperatura ambiente, houve aumento no deslocamento por tosse (96 ± 50 vs. 118 ± 61 mm) e diminuição do ângulo de contato (32 ± 6 vs. 27 ± 6 graus) (p < 0,05). Para o muco hialino não houve alterações nas medidas analisadas. CONCLUSÃO: O muco traqueobrônquico hialino pode ser armazenado em temperatura ambiente por 24 h sem que haja alterações em sua transportabilidade por ação ciliar ou em seu ângulo de contato. Por outro lado, o muco purulento não deve permanecer em temperatura ambiente por muitas h para que não se altere seu ângulo de contato e sua transportabilidade por tosse.

[Managing lower respiratory tract infections in immunocompetent patients. Definitions, epidemiology, and diagnostic features]

Les infections respiratoires basses sont une des principales cause de mortalité dans le monde et les pneumopathies représentent en France la première cause de décès d'origine infectieuse. Trois entités nosologiques distinctes sont habituellement isolées en fonction de la localisation infectieuse : la bronchite aiguë, la pneumopathie et la bronchopneumopathie (atteignant les bronches et le parenchyme pulmonaire). En cas d'infections de l'arbre bronchique dans le cadre d'une bronchopathie chronique on parle de décompensation infectieuse de la maladie bronchique. Les deux principales difficultés diagnostiques de ces infections sont de déterminer la présence d'une participation alvéolaire au processus infectieux et de définir l'agent (ou les agents) pathogènes. Ces deux éléments vont conditionner la prise en charge thérapeutique. En dehors de l'examen physique, indispensable dans ce contexte, seule la radiographie thoracique pourra, en cas de persistance d'un doute, permettre de confirmer la présence d'une participation alvéolaire. Le diagnostic microbiologique pose la question de sa nécessité systématique et celui de sa valeur. Il n'est pas indispensable de réaliser un diagnostic microbiologique de certitude dans tous les cas. La décision de documentation doit répondre à deux impératifs : faisabilité et valeur diagnostique. La valeur d'un prélèvement dépend de son aptitude à mettre en évidence l'agent pathogène et dans certains cas de la possibilité d'en déterminer le profil de sensibilité (qui reste une indication majeure à la réalisation de ces prélèvements).

Community-acquired pneumonia. A prospective outpatient study

We initiated a prospective study with a group of practitioners to assess the etiology, clinical presentation, and outcome of community-acquired pneumonia in patients diagnosed in the outpatient setting. All patients with signs and symptoms suggestive of pneumonia and an infiltrate on chest X-ray underwent an extensive standard workup and were followed over 4 weeks. Over a 4-year period, 184 patients were eligible, of whom 170 (age range, 15-96 yr; median, 43 yr) were included and analyzed. In 78 (46%), no etiologic agent could be demonstrated. In the remaining 92 patients, 107 etiologic agents were implicated: 43 were due to "pyogenic" bacteria (39 Streptococcus pneumoniae, 3 Haemophilus spp., 1 Streptococcus spp.), 39 were due to "atypical" bacteria (24 Mycoplasma pneumoniae, 9 Chlamydia pneumoniae, 4 Coxiella burnetii, 2 Legionella spp.), and 25 were due to viruses (20 influenza viruses and 5 other respiratory viruses). There were only a few statistically significant clinical differences between the different etiologic categories (higher age and comorbidities in viral or in episodes of undetermined etiology, higher neutrophil counts in "pyogenic" episodes, more frequent bilateral and interstitial infiltrates in viral episodes). There were 2 deaths, both in patients with advanced age (83 and 86 years old), and several comorbidities. Only 14 patients (8.2%) required hospitalization. In 6 patients (3.4%), the pneumonia episode uncovered a local neoplasia. This study shows that most cases of community-acquired pneumonia have a favorable outcome and can be successfully managed in an outpatient setting. Moreover, in the absence of rapid and reliable clinical or laboratory tests to establish a definite etiologic diagnosis at presentation, the spectrum of the etiologic agents suggest that initial antibiotic therapy should cover both S. pneumoniae and atypical bacteria, as well as possible influenza viruses during the epidemic season.

Intra and inter technologist variability in the quality assessment of respiratory tract specimens

The majority of microbiology laboratories have implemented quality improvement procedures such as a Q scoring system to assess the nature of clinical specimens. Our study reviewed the sources and the amount of variation when Q scoring of lower respiratory secretions was performed. In total, 450 slides representing lower respiratory tract secretions were Q scored by three experienced technologists. Total agreement regarding the number of neutrophils, squamous epithelial cells and Q scores was 76%, 57% and 57% respectively. The major factor influencing Q score values was the enumeration of epithelial cells. From our findings, we expect that there is greater variability in Q scoring then is generally acknowledged and there is a substantial degree of subjectivity on part of individual technologists reading gram stains.

The reproducibility of sputum gram film interpretation

OBJECTIVES

To evaluate the reproducibility with which microbiologists interpret Gram-stained sputa and examine the effect of the smear preparation method.

METHODS

Two hundred and ten coded slides prepared directly from a purulent portion of sputum (DS) and 140 slides prepared after homogenization of the same sputum (HS) were examined by three experienced microbiologists. A proportion of the slides prepared by each method were recorded and represented to the raters. Intraobserver and interobserver variation was assessed using the kappa statistic (kappa).

RESULTS

Evaluation of the smear as being infected and predicting Streptococcus pneumoniae as the infecting organism showed the greatest intraobserver agreement (kappa=0.74-0.82) and interobserver agreement (kappa=0.50-0.82). The agreement concerning the number of cells and infection with Haemophilus influenzae was only fair to moderate. Differences in the interpretation of smears prepared by the two methods could be explained by the intrinsic disagreement that occurs when the same smear is examined twice. The positive predictive value of a positive S. pneumoniae smear for a positive culture ([10(6)/ml) was 81% with the DS and 97% with the HS.

CONCLUSION

In this laboratory, a sputum Gram film interpretation suggesting infection with S. pneumoniae was reproducible and predictive of a significant positive culture.

Community-acquired pneumonia

Community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide and has significant financial implications for health-care systems. The epidemiology and fundamental biology of the disease has evolved, reflecting the human immunodeficiency virus pandemic, increasing world travel, and, as always, poverty. The promise held out by molecular diagnostic technology has yet to deliver in this arena, and antibiotic resistance continues to drive the quest for new antimicrobial agents. The emergence of multidrug-resistant Streptococcus pneumoniae, the microorganism most often implicated as a cause of CAP, continues to threaten treatment options. The evolution of this organism, the persistently high mortality rate associated with CAP, and increasing health-care costs have prompted the publication of guidelines by various authorities that can be used to assist in the initial assessment of the patient and then guide empirical antimicrobial therapy. It is unclear whether these guidelines will have significant impact on cost and mortality, although the trend toward a rational and evidence-based approach to antimicrobial therapy must be a goal to aspire to.

Diagnostic testing for community-acquired pneumonia

The microbial cause of community-acquired pneumonia can be identified by noninvasive means in the majority of cases, usually within a few days of presentation. The Gram stain and culture of a pretreatment sputum sample are the most useful tests, but have significant limitations. Methods for detecting pneumococcal antigen in respiratory secretions are particularly helpful in patients who have received antibiotics before evaluation. Testing for specific pathogens such as L. pneumophila, M. pneumoniae, or C. pneumoniae should be guided by clinical suspicion in individual circumstances. Invasive procedures are most helpful in patients suspected of having infection with opportunistic or resistant pathogens, and in those whose initial management has been unsuccessful.

Evolving approaches to management of quality in clinical microbiology

Quality management in clinical microbiology began in the 1960s. Both government and professional societies introduced programs for proficiency testing and laboratory inspection and accreditation. Many laboratory scientists and pathologists were independently active and creative in expanding efforts to monitor and improve practices. The initial emphasis was placed on intralaboratory process. Later, attention was shifted to physician ordering, specimen collection, reporting, and use of information. Quality management in the laboratory depends in large part on the monitoring of indicators that provide some evidence of how laboratory resources are being used and how the information benefits patient care. Continuous quality improvement should be introduced. This consists of a more thorough assessment of doing the right things versus the wrong things in terms of customer demand and satisfaction and studying the cumulative effect of error when responsibility is passed from one person to another. Prevention of error is accomplished more through effective training and continuing education than through surveillance. Also, this system will force more conscious attention to meeting the expectations of the many customers that must be satisfied by laboratory services, including patients, physicians, third-party payers, and managed-care organizations.

Sputum quality: can you tell by looking?

BACKGROUND

Nurses are responsible for the collection of sputum samples for culture in most institutions, yet they receive little formal training on what a good specimen looks like.

METHODS

Three hundred thirty-three consecutively collected expectorated sputum samples and tracheal aspirates were examined to determine the relationship of macroscopic specimen appearance (watery, mucoid, mucopurulent) to specimen quality (good, fair, poor).

RESULTS

Of the expectorated sputum samples, 21% were watery, 65% were mucoid, and 14% were mucopurulent. Sixty-five percent of the expectorated sputum samples were good or fair, regardless of appearance. Eighty-seven percent of mucopurulent expectorated sputum samples were good or fair. In the remaining nonmucopurulent specimens, however, there were no predictable markers of specimen quality.

CONCLUSIONS

The only specimens that were predictably good were those that were mucopurulent yellow, yellow, or tracheal aspirates.

Diagnosis of pulmonary infections in patients infected with the human immunodeficiency virus

Over a three-year period, 54 episodes of pneumonia were diagnosed in 45 adults infected with the human immunodeficiency virus (HIV). These episodes were reviewed in order to assess the distribution of pathogens and their clinical presentation. Thirty-six episodes were due to an opportunistic pathogen (Pneumocystis carinii in 31, Mycobacterium avium complex in 3, Mycobacterium tuberculosis in 2), and 18 were caused by non-opportunistic pathogens (11 Streptococcus pneumoniae, 2 Haemophilus influenzae, 5 unknown pathogens that responded to broad-spectrum antibiotics). Non-opportunistic pneumonias were characterized by an abrupt onset (18/18 had pulmonary symptoms of less than 7 days duration), high fever (13/18), and focal lung infiltrates (17/18). In contrast, opportunistic infections infrequently presented with pulmonary symptoms of less than 7 days duration (3/36) or high fever (7/36), and most of the chest radiograms (34/36) disclosed a diffuse lung infiltrate. In HIV-infected patients presenting with pneumonia, simple clinical and radiological data may point to bacterial pathogens. Such data could be used in selected cases to spare invasive procedures and to start empirical antibiotic therapy.

Bronchoscopic protected catheter brush for the diagnosis of pulmonary infections

A new bronchoscopic-protected catheter brush (BPCB), designed to obtain uncontaminated bronchial secretions, was studied in vitro and in vivo. The device was composed of a standard biopsy brush, protected by a single catheter and occluded with an agar plug. Ejection of the plug was obtained neither by advancing the brush nor by advancing an inner cannula (as in a telescoping catheter brush), but instead, by an air flux, provided by a syringe which was connected to the proximal tip. In the first part of the study the ability of the BPCB to obtain uncontaminated specimens was tested in comparison with the reference telescoping catheter brush (BFW brush 10/70/90, Medi-Tech Corp Watertown, MA). Catheters of each type were successively passed through the inner channel of a bronchofiberscope which was contaminated with Klebsiella pneumonia. After ejection of the distal plug, sampling of bronchial secretions infected with a marker organism (Pseudomonas aeruginosa), was performed with the brush. Culture of brush specimens of each type of catheter grew the marker organism in pure culture and obtained the same amount of bronchial secretions (0.001 ml). The manual vortexing of the brush in the transport medium (Ringer's solution) proved to be as effective as the mechanical vortexing so that transecting of the brush was no longer mandatory. In the second part of this study, paired bronchial samplings from 27 patients were performed using both types of catheters and similar results for both were obtained. In these in vitro studies, completed by a clinical trial, our single-sheathed, plugged catheter brush proved to be as reliable as the double telescoping catheter brush. However, because of its relatively simple conception, making it easier to use and lower in cost than the double catheter brush, routine use of this sampling device should be considered.

Randomized trial interpreting sputum quality in a clinical laboratory

The role for laboratory interpretation of microbiologic results remains controversial, and many laboratories leave the interpretation of culture results entirely to physicians. We examined the effects of furnishing a laboratory interpretation of sputum quality on physician decision making. Quality of sputum was determined on Gram-stained smears by using a modification of the criteria of Bartlett (R. C. Bartlett, Medical Microbiology: Quality, Cost, and Clinical Relevance, p. 24-31, 1974). A total of 301 poor-quality specimens were randomized either to receive written interpretation of Gram stain results or to a control group for which Gram stain results were reported without interpretation. Physicians were more likely to follow up a poor-quality specimen with a second specimen if they had been furnished an interpretation of the results from the original Gram stain (22 versus 12%; P = 0.025). We conclude that laboratory-based interpretation of microbiologic results can improve physician decision making.

Routine use of counterimmunoelectrophoresis for the detection of pneumococcal antigen in sputum

Sputum samples obtained routinely for culture from patients at a thoracic department were also examined for pneumococcal antigen by means of counterimmunoelectrophoresis (CIE), using a polyvalent antipneumococcal type serum (omniserum). Pneumococci were found in 1.3% of the 880 cultures, whereas pneumococcal antigen was detected with CIE in 6.5%. The validity of these findings was tested by correlating them with the presence of clinical symptoms in those with positive tests and also by antigen detection in ELISA using monoclonal antibodies specific for the C-polysaccharide common to all types of pneumococci. Clinical findings corresponding to confirmed or probable current chest infection were found in 36 of the 48 patients with positive CIE. ELISA was positive in 33 of the 38 patients with positive CIE who were tested. Although the study deals with an unselected material of chest patients, it indicates that CIE is a sensitive method and that it is independent of current antibiotic treatment. Pneumococcal infection is probably of importance in exacerbations of chronic obstructive lung disease, but the clinical usefulness of detecting pneumococcal and other antigens in this patient group needs to be studied further.

Sputum analysis and culture

Sputum analysis and culture is the most common method of specific diagnosis of lower respiratory tract infections. Culture of a properly screened, expectorated sputum sample will identify the pathogen in most cases of bacterial pneumonia. Expectorated sputa, as well as those obtained by aspiration from the upper airway, are subject to oropharyngeal bacterial contamination. Other techniques, such as transtracheal aspiration, are more "sterile," but have a much higher incidence of morbidity. Microscopic screening of expectorated or aspirated sputum samples will reduce the number and increase the diagnostic accuracy of cultures, resulting in considerable cost savings. Mucopurulent material is selected by gross inspection, and microscopic examination of a wet mount and Gram stain yields information about cell type and predominant organism. More important, however, the presence of fewer than 25 squamous epithelial cells per low-power field indicates that true lower respiratory tract secretions have been collected. Culture results must be correlated carefully with semiquantitative grading, initial microscopic screening, clinical presentation, and response to initial therapy. When properly performed and interpreted, sputum analysis and culture are valuable tools in the diagnosis and treatment of lower respiratory tract infection.

Comparison of Gram stain and Nomarski optics for screening sputum specimens before culture

Although the Gram stain is usually used to screen sputum specimens prior to culture, wet mount observation with Nomarski optics has been suggested as a useful alternative. We compared the two methods and found that more specimens were rejected by the Gram stain technique without eliminating any that yielded important clinical information.

Incidence of Branhamella catarrhalis in the sputa of patients with chronic lung disease

The incidence of Branhamella catarrhalis in the respiratory tract of adults, especially in the United States, is not known. During the 30-month period from January 1983 to June 1985, 4180 sputum and endotracheal samples from patients in a hospital for chest diseases were evaluated. All samples were acceptable for Gram-stain analysis and/or culture based on published cellular criteria. Using primarily Gram-stain directed cultures, 220 isolates of B. catarrhalis were identified in 180 patients, being present in 5.3% of all sputum cultures and 11.5% of those positive for a pathogen. B. catarrhalis was the fourth most common pathogen identified. It was found in pure culture (124) and mixed culture (96), the latter usually in association with Haemophilus influenzae or Streptococcus pneumoniae. Of the 220 B. catarrhalis isolates, 158 (71.8%) were positive for beta-lactamase. The number and incidence of B. catarrhalis varied, with the organism being most prevalent during the winter months. Despite its frequent presence in sputum, B. catarrhalis was not recovered from pleural fluid or blood during the same period. This study demonstrates the frequent presence of B. catarrhalis in the sputum of adults with chronic lung disease, although the role of this organism as a pathogen was not determined.

Amoxicillin-clavulanic acid in the treatment of lower respiratory tract infections caused by beta-lactamase-positive Haemophilus influenzae and Branhamella catarrhalis

Twenty-one adult patients hospitalized with lower respiratory tract infections due to Branhamella catarrhalis or Haemophilus influenzae or both were treated with the combination of oral amoxicillin and potassium clavulanate (Augmentin) in an open, noncomparative clinical trial. Diseases included pneumonia, empyema, and exacerbations of bronchiectasis and chronic lung disease. Thirteen of 16 B. catarrhalis and six of nine H. influenzae isolates were beta-lactamase positive. The patients with B. catarrhalis were treated for a mean of 5.3 days, and those with H. influenzae were treated for a mean of 7.0 days. The overall response to therapy was excellent, with 18 of 19 beta-lactamase-producing strains eradicated on therapy. One patient secondarily infected with Pseudomonas aeruginosa was a clinical failure, and two patients with H. influenzae who became culture positive again after therapy were considered microbiologic failures. Gastrointestinal side effects (especially nausea) were common, although all patients completed a course of therapy. Sputum levels of amoxicillin were surprisingly low (less than 0.05 to 0.54 micrograms/ml), a finding which may explain the high relapse rate (22%) seen with H. influenzae, as these are below the usual MICs of amoxicillin for this organism. The combination of amoxicillin plus potassium clavulanate appears to be an excellent drug for treatment of beta-lactamase-producing strains of these two species, although mild gastrointestinal side effects are common.