Capsular serotypes and antibiotic sensitivity of Streptococcus pneumoniae isolated from primary-school children

Metabolomics and Its Application to Acute Lung Diseases

Metabolomics is a rapidly expanding field of systems biology that is gaining significant attention in many areas of biomedical research. Also known as metabonomics, it comprises the analysis of all small molecules or metabolites that are present within an organism or a specific compartment of the body. Metabolite detection and quantification provide a valuable addition to genomics and proteomics and give unique insights into metabolic changes that occur in tangent to alterations in gene and protein activity that are associated with disease. As a novel approach to understanding disease, metabolomics provides a "snapshot" in time of all metabolites present in a biological sample such as whole blood, plasma, serum, urine, and many other specimens that may be obtained from either patients or experimental models. In this article, we review the burgeoning field of metabolomics in its application to acute lung diseases, specifically pneumonia and acute respiratory disease syndrome (ARDS). We also discuss the potential applications of metabolomics for monitoring exposure to aerosolized environmental toxins. Recent reports have suggested that metabolomics analysis using nuclear magnetic resonance (NMR) and mass spectrometry (MS) approaches may provide clinicians with the opportunity to identify new biomarkers that may predict progression to more severe disease, such as sepsis, which kills many patients each year. In addition, metabolomics may provide more detailed phenotyping of patient heterogeneity, which is needed to achieve the goal of precision medicine. However, although several experimental and clinical metabolomics studies have been conducted assessing the application of the science to acute lung diseases, only incremental progress has been made. Specifically, little is known about the metabolic phenotypes of these illnesses. These data are needed to substantiate metabolomics biomarker credentials so that clinicians can employ them for clinical decision-making and investigators can use them to design clinical trials.

Pneumococcal pneumonia: potential for diagnosis through a urinary metabolic profile

Pneumonia, an infection of the lower respiratory tract, is caused by any of a number of different microbial organisms including bacteria, viruses, fungi, and parasites. Community-acquired pneumonia (CAP) causes a significant number of deaths worldwide, and is the sixth leading cause of death in the United States. However, the pathogen(s) responsible for CAP can be difficult to identify, often leading to delays in appropriate antimicrobial therapies. In the present study, we use nuclear magnetic resonance spectroscopy to quantitatively measure the profile of metabolites excreted in the urine of patients with pneumonia caused by Streptococcus pneumoniae and other microbes. We found that the urinary metabolomic profile for pneumococcal pneumonia was significantly different from the profiles for viral and other bacterial forms of pneumonia. These data demonstrate that urinary metabolomic profiles may be useful for the effective diagnosis of CAP.

Self-assessed occupational health and working environment of female nurses, cabin crew and teachers

AIM

The aim of this study was to describe and compare the self-assessed occupational health among female nurses, cabin crew and teachers, in relation to their working environment.

BACKGROUND

Similarities between the three occupations, i.e. predominantly female and service-oriented, render them interesting in comparison with respect to health and working environment.

METHODS

The participants were female Icelandic cabin crew, nurses and elementary school teachers. A questionnaire including items on socio-demographics, working environment (addressing work pace, job security, monotonous work, assistance, physically strenuous work and physical environmental factors) and a symptom list was used for data collection. Factor analyses on the symptom list resulted in five symptom scales: Musculoskeletal, Stress and exhaustion, Common cold, Gastrointestinal and Sound perception scale. A total of 1571 questionnaires were distributed. The response rate was 65.7-69%, depending on occupation. Data were collected in 2002.

RESULTS

Cabin crew reported worse gastrointestinal, sound perception and common cold symptoms than nurses and teachers. Cabin crew and teachers reported worse symptoms of stress and exhaustion than nurses (p < 0.05). When compared with teachers and nurses cabin crew reported less job security and more physically strenuous and monotonous work. Nurses were likelier to seek assistance from co-workers or patients as well as to take care of an older relative than teachers and cabin crew. Regression analysis found that within each occupation distress from environmental factors resulted in higher score on all the symptom scales.

CONCLUSIONS

Nurses experience less stress and exhaustion than teachers and cabin crew. In comparison with one or both of the other occupations nurses are more likely to assist each other with their work, experience job security, reporting physically complex work and take care of older relatives. This should be highlighted as positive aspects of nurses' work praised as displaying responsibility and interconnectedness of nurses'.

PCR-based assays for detection of Streptococcus pneumoniae serotypes 3, 14, 19F and 23F in respiratory specimens

Current culture-based assays are insensitive for detection of simultaneous respiratory tract colonization by more than one pneumococcal serotype. Separate single-tube, nested PCR-based assays have been developed to detect Streptococcus pneumoniae serotypes 3, 14, 19F and 23F by amplifying unique DNA sequences in the capsular polysaccharide gene cluster of each serotype. Pairs of 27-32-base outer primers and 20-21-base inner primers and a 20-22-base probe were designed to amplify and detect a 200-221-base sequence by dot blotting using the labelled probe. Sensitivity of the assays was 0.01-10 fg using chromosomal DNA and < or = 1 viable cell using DNA extracted from exponential-phase bacteria. Each serotype-specific assay detected chromosomal DNA from all of five to ten clinical isolates of the homologous type and did not detect DNA sequences from any of 190-204 strains from 51-52 different serotypes or 28 non-pneumococcal bacterial strains. Sixteen throat swabs from children that had been cultured for S. pneumoniae were tested in PCR assays following DNA extraction. All of six that grew S. pneumoniae serotype 3, 14, 19F or 23F were positive in the PCR assay for the homologous serotype (and in a PCR assay for sequences in lytA, present in all pneumococci) and were negative in assays for other serotypes. Of eight culture-negative specimens in children not receiving antimicrobials, three were positive for both the lytA assay and an assay for one of the four serotypes, suggesting true positive results; in three others all five PCR assays were negative and, in the remaining two, the lytA assay was positive but each of the four assays for individual serotypes was negative, suggesting either false-positive results or presence of DNA sequences from an S. pneumoniae serotype other than 3, 14, 19F or 23F. These preliminary clinical data suggest that these PCR-based assays are sensitive and specific for detection of individual serotypes of pneumococci and may be used with respiratory tract specimens.

Pneumococcal nasopharyngeal carriage in children following heptavalent pneumococcal conjugate vaccination in infancy

AIMS

To ascertain whether the reduction in nasopharyngeal carriage of vaccine serotypes induced by pneumococcal conjugate vaccine (PnCV) administered to infants persists beyond the age of 2 years.

METHODS

Non-randomised, unblinded controlled study of 2-5 year old children who had received three doses of heptavalent PnCV (7VPnCV) in infancy and 23-valent pneumococcal polysaccharide vaccine at 13 months, and unimmunised controls. Nasopharyngeal swabs were taken in summer (150 vaccinated subjects, 126 controls) and winter (143 vaccinated subjects, 188 controls). The swabs were cultured and serotyped for Streptococcus pneumoniae.

RESULTS

Carriage rates (vaccinated subjects: 24.7% and 43.4%; controls: 27.0% and 41.0%, in summer and winter respectively) and carriage of vaccine serotypes (subjects: 10.0% and 30.0%; controls: 13.5% and 31.5%, in summer and winter respectively) were similar in the two groups.

CONCLUSIONS

Effects of vaccination in infancy on rates of nasal carriage of pneumococcus and serotype replacement in children living in a largely unvaccinated population are no longer evident by 2-5 years of age.

Streptococcus pneumoniae nasopharyngeal carriage prevalence, serotype distribution, and resistance patterns among children on Lombok Island, Indonesia

Few data exist on childhood pneumococcal carriage prevalence, serotype distribution, and resistance patterns for Indonesia, the world's fourth most populous country. During August 1997, nasopharyngeal samples were collected from a population-based, island-wide sample of 484 healthy children (age, 0-25 months) from Lombok Island, Indonesia. Two hundred twenty-one pneumococcal isolates were identified, for a carriage prevalence of 48%; 66% of isolates were of serogroup or serotype 6, 23, 15, 33, or 12. All isolates were susceptible to penicillin and cefotaxime. Twelve percent of the isolates were nonsusceptible to sulfamethoxazole or chloramphenicol and 4% were nonsusceptible to both of these drugs. Nonsusceptible organisms were most frequently serogroup or serotype 6, 12, and 33. Lombok has a moderate pneumococcal carriage prevalence and a relatively low proportion of resistant isolates. At least 3 of the 5 most common serogroups and serotypes and 2 of the 3 most common nonsusceptible serogroups and serotypes are not included in the current 7-valent pneumococcal conjugate vaccine.

Carriage of penicillin-susceptible and non-susceptible pneumococci in healthy young children in Göteborg, Sweden

OBJECTIVES

To study carriage of Streptococcus pneumoniae among healthy young children, determine the proportion of strains with decreased susceptibility to penicillin, and study possible risk factors for the carriage of penicillin-resistant strains.

METHODS

Between February 1996 and February 1997, 620 healthy, 18-month-old children in Goteborg, Sweden were screened for carriage of S. pneumoniae with decreased susceptibility to penicillin. Nasopharyngeal samples were obtained from children visiting child health centres for routine health control.

RESULTS

Streptococus pneumoniae was found in 322 samples and 18 strains (5.6%, CI95 3.4; 8.8) of all pneumococci showed decreased susceptibility to penicillin G with minimum inhibitory concentrations (MICs) ranging from 0.125 to 1.0 mg/l. The proportion of strains with decreased susceptibility was similar to that found in a laboratory-based material (6%), from the same geographical area and time period. A majority of the children with strains with decreased susceptibility to penicillin (n = 11) were not attending day-care centres.

CONCLUSIONS

The prevalence of S. pneumoniae with reduced susceptibility to penicillin is still low in unselected healthy Swedish children.

Rapid and reliable identification of Streptococcus pneumoniae isolates by pneumolysin-mediated agglutination

A pneumolysin-based agglutination test which allows an easy, rapid, cost-effective, and accurate (100% specific and 95% sensitive) discrimination between pneumococci and other related human and animal pathogenic bacterial strains has been assayed.

Pneumococcal resistance patterns in Europe

The emergence of Streptococcus pneumoniae strains with decreased susceptibility to penicillin has been reported worldwide over the past 20 years. However, there are striking discrepancies in penicillin susceptibility among various European countries, suggesting that local conditions may affect clonal propagation or de novo selection of resistant strains. In the present study, data on penicillin resistance patterns, antibiotic use and mode of administration, and treatment compliance in five European countries (France, Spain, Germany, Italy, and the UK) were compared. High prevalence rates of penicillin-resistant pneumococci have been reported in Spain and France, where antibiotics are widely prescribed, and overall in Europe, patient compliance with more than 50% of oral antimicrobial prescriptions is inadequate. The low prevalence of penicillin resistance in Germany and the UK coincides with lower antibiotic consumption and better treatment compliance in these countries. Recent attempts to raise public awareness and to restrict and improve indications for antimicrobial agents have resulted in decreased pneumococcal resistance in Hungary and Iceland, suggesting that pneumococcal resistance can be reversed.

Antibiotic management of pneumococcal infections in an era of increased resistance

Pneumococci are a leading cause of bacterial meningitis and bacteraemia, as well as pneumonia, otitis media and sinusitis in childhood. These organisms recently have shown a dramatic increase in antibiotic resistance. Penicillin-resistant pneumococci are of special concern as they are often resistant to other unrelated antibiotics. This is of particular significance to Aboriginal children who have among the highest rates of pneumococcal infection in the world. Laboratories should now test all invasive pneumococcal isolates for penicillin and third generation cephalosporin resistance. Local treatment guidelines are required for pneumococcal infections, especially for meningitis, taking into account the prevalence of resistant strains within the community. At present, penicillin and amoxycillin remain the drugs of choice for pneumococcal infections, with the exception of meningitis where initial empirical therapy must be with a third generation cephalosporin. Judicious antibiotic use, which avoids over-prescribing and unnecessary use of broad-spectrum agents, improved living standards in underprivileged communities and introduction of an effective conjugate vaccine, able to reduce the rates of pneumococcal infection and hopefully colonization, may limit the spread of resistant strains.