Previous Antibiotic Treatment Research Articles

What is an uncultured bacterial pathogen?: Molecular approaches to a clinical problem

Molecular techniques such as broad-range amplification of 16S rRNA gene sequences allow a culture independent approach for detection of infectious agents. Over the past decade this strategy has resulted in the recognition of a number of uncultured or difficult to culture pathogens. A variety of pitfalls need to be addressed before postulating a causal relationship between the nucleic acid sequence of an uncultured agent and a clinical disease. In principle, cultural procedures for recovery of bacterial pathogens are well developed and established. Several conditions may result in non recognition of an infectious pathogen in the diagnostic laboratory, such as tedious isolation procedures or previous antibiotic treatment. Certain microbes may require special culture conditions and failure to consider these pathogens may result in negative culture. Broad-range 16S rRNA gene amplification is particularly useful for detecting infectious agents of unknown identity under disease conditions in which there is circumstantial evidence for a bacterial etiology, e.g. infectious endocarditis. Molecular diagnostic procedures have left the stage of a scientific challenge and have become a technology issue. Problems to be addressed in this regard include contamination of gene amplification reagents with exogenous nucleic acids and the quality of public data bases. Besides mere laboratory investigations studying the performance of molecular diagnostic techniques, the clinical utility of molecular diagnostic procedures has to be addressed.

Análisis clínico y de los factores de riesgo de mortalidad de 86 casos de endocarditis infecciosa en niños y adolescentes en Argentina (1988-2000)

IE is a rare infection in children. Scarce reports with large number of patients are published. Between January 1988 to December 2000 we analyzed all cases of IE cases admitted to our hospital. 86 cases of IE (4.9/10,000 admissions) in 86 children were diagnosed. The median age was 7.6 years. In 77% of patient previous cardiac disease was detected, interventricular defects and Tetralogy of Fallot were the more frequent. Three percent of children had rheumatic heart disease. Thirty-six percent of children had previous heart surgery. Fifty-seven percent have been received previous antibiotics. Eighty-seven percent had positive blood cultures, being the S. aureus and S. viridans the predominantly. Forty-eight percent of children had complications. The metabolic disorders and the nosocomial infections were the most frequent. Twenty-four percent required surgery, 24% of them in the first week of the diagnosis. The mortality in operated children was 19%. In the multivariate analysis we could observe that children with more than 7 years and S. aureus isolation in blood cultures had more incidence of complications and posterior surgery (p < 0.05). Children with S. aureus IE had longer duration of fever, more incidence of complications than patients with S. viridans IE (p < 0.05). Ten percent of children were treated as outpatients. The global mortality was 12,8%. Previous surgery (OR = 6.89; IC 95% 1.54-30.7) and previous antibiotic treatment (OR = 9.98; IC 95% 1.12-88.8) were the factors related with higher mortality in the multivariate analysis. S. aureus was the predominat pathogen and caused more morbidity and mortality than S. viridans IE. Children with IE with previous surgery and previous antibiotic treatment died with more frequency.

Antimicrobial resistance in Staphylococcus spp., Escherichia coli and Enterococcus spp. in dogs given antibiotics for chronic dermatological disorders, compared with non-treated control dogs

The aim of this study was to evaluate antimicrobial resistance in canine staphylococci, Escherichia coli and enterococci, which were isolated from 22 dogs with pyoderma and a history of previous antibiotic treatment, compared to bacterial isolates from 56 non-treated control dogs. Two isolates of each bacterial species per dog were investigated, if detected. Staphylococcal isolates from dogs with pyoderma (35 isolates) were more resistant to sulphatrimethoprim than the isolates from controls (56 isolates) (57% vs. 25%, p < 0.004). Multiresistance in staphylococci was also more common in dogs with pyoderma (29% vs. 9%, p = 0.02). A similar trend among isolates of E. coli was detected (24 and 74 isolates from treated and control dogs, respectively), but the differences were not significant. Resistance for macrolide-lincosamides was approximately 20% among staphylococci in both groups. Resistance to ampicillin among enterococci was 4%–7%. The age of the dogs might have an impact on resistance: multiresistance among staphylococcal isolates from younger dogs (≤5 years) was more common than in older dogs (≥6 years) (24%, vs. 0%, 63 and 27 isolates, respectively, p = 0.02). Staphylococci in younger dogs were more resistant to tetracycline (48% vs. 11%, p < 0.001) and sulphatrimethoprim (48% vs. 15%, p < 0.01) than those in older dogs. In contrast, the isolates of E. coli from older dogs tended to be more resistant, although a significant difference was detected only in resistance to tetracycline (13% vs. 2% of 40 and 50 isolates respecthely, p = 0.04)). The results of this small study indicate that resistance in canine staphylococci in the capital area of Finland is comparable with many other countries in Europe. Resistance in indicator bacteria, E. coli and enterococci, was low.

The knowledge and expectations of parents about the role of antibiotic treatment in upper respiratory tract infection – a survey among parents attending the primary physician with their sick child

BackgroundUpper respiratory tract infections (URTI) are common. The etiologic factor is usually viral, but many physicians prescribe antibiotics. We aimed to evaluate parents' expectations of and knowledge about the role of antibiotics in childhood URTI.MethodsThe study was conducted in thirteen primary care pediatric clinics. Parents of children aged 3 months to 6 years who attended with URTI symptoms were included when it was the first attendance in the current illness. Questionnaire about the current illness, reasons for attending and expectations from the visit, knowledge about URTI was filled before the visit.ResultsIn 122 visits the average age was 2.8 ± 1.9 years. The main reasons for the visit were to avoid complications (81%) and to be examined (78%). Expected treatment was: cough suppressants (64%), anti-congestants (57%), paracetamol (56%), natural remedies (53%) and antibiotics (25%). In 28% the child had received antibiotics in past URTI. Only 37% thought that antibiotics would not help in URTI and 27% knew that URTI is a self-limited disease. 61% knew that URTI is a viral disease. Younger parental age and higher education were associated with lower expectations to receive antibiotics (p = 0.01, p < 0.005 respectively). While previous antibiotic treatment (p < 0.001), past perceived complications (p = 0.05) and the thought that antibiotics help in URTI (p < 0.001) were associated with a greater expectation for antibiotics.ConclusionsA quarter of the parents attending the physician with URTI are expecting to get antibiotics. Predictors were lower education, older parental age, receiving antibiotics in the past and the belief that antibiotics help in URTI.

Intravenous Antibiotics for Refractory Rhinosinusitis in Nonsurgical Patients: Preliminary Findings of a Prospective Study

Some patients with persistent chronic sinusitis have either had unsuccessful surgery or have simply refused surgery. In nonsurgical candidates, when oral antibiotics and traditional therapy are unsuccessful, home intravenous (i.v.) antibiotics present an effective alternative. Forty-five patients were assessed before treatment using a semiquantitative scoring system and visual analog scales to measure major and minor symptoms of rhinosinusitis. Computed tomography (CT) scans were assessed using the Lund-MacKay staging system; nasal endoscopic findings were documented. Seven patients had nasal endoscopy and CT results. Medical diseases known to be associated with rhinosinusitis were documented. Endoscopic-guided culture and sensitivities were obtained. After successful insertion and radiological placement confirmation, home i.v. antibiotics were administered via a peripherally inserted central catheter line. Antibiotic choice was based on the culture and sensitivity reports. Treatment continued for 6 weeks; subsequent cultures were obtained at weeks 3, 6, and 9. Nasal endoscopy was performed, and rhinosinusitis symptoms were assessed at weeks 3, 6, and 9. Follow-up CT scans were obtained at week 12 in a subset of patients. Significant improvement in symptom analysis was seen in patients receiving home i.v. antibiotics when previous oral antibiotic treatment and/or surgery had failed. Home i.v. antibiotics provide an excellent alternative to surgery for patients who have either had unsuccessful surgery or who have refused surgery.

Acute pyelonephritis in adults: prediction of mortality and failure of treatment.

To formulate a classification tool for early recognition of patients admitted with acute pyelonephritis (AP) who are at high risk for failure of treatment or for death. A retrospective chart review of 225 patients (102 men) admitted with AP. We considered 13 potential risk factors in a multivariate analysis. Recent hospitalization, previous use of antibiotics, and immunosuppression were found to be independent correlates of the prevalence of resistant pathogens in both sexes. Additional predictors included nephrolithiasis in women and a history of recurrent AP in men. Prolonged hospitalization should be expected for a man with diabetes and long-term catheterization who is older than 65 years or for a woman of any age with the same characteristics, when the initial treatment was changed according to the results of urine culture. For mortality prediction, we derived an integer-based scoring system with 6 points for shock, 4 for bedridden status, 4 for age greater than 65 years, and 3 for previous antibiotic treatment for men and 6 points for shock, 4 for bedridden status, 4 for age greater than 65 years, and 3 for immunosuppression for women. Among patients with at least 11 points, the risk for in-hospital death was 100% for men and 91% for women. Simple variables available at presentation can be used for risk stratification of patients with AP. The additional identification of certain risk factors by means of a carefully obtained history could contribute to early recognition of patients infected by resistant bacteria and optimize the selection of antimicrobial agents.

Aumento de la rentabilidad diagnóstica en la enfermedad meningocócica mediante la técnica de reacción en cadena de la polimerasa

The objective of the present study was to evaluate the application of a rapid and simple PCR technique to diagnose meningococcal disease. A retrospective study was undertaken from January 1999 to June 2002, comprising 110 samples of cerebrospinal fluid (CSF) or plasma from 110 different pediatric patients attending the Hospital Sant Joan de Déu of Barcelona. The selection of patients was based on their diagnosis at discharge: Forty three patients had a discharge diagnose of meningococcal disease (13 meningitis, 12 sepsis and 18 sepsis with meningitis) while 67 had clinical conditions other than meningococcal disease. The samples were processed following standard bacteriological methods (Gram smear and culture) and a PCR technique designed to amplify a segment of the meningococcal insertion sequence IS1106 was performed. Sensitivity of PCR in the group of patients with a clinical diagnosis of meningococcal disease was 93% while sensitivity of the culture was 55.8%. Samples from 19 patients were processed once treatment with -lactam antibiotics had begun (range 8-144 hours), and positive PCR results were seen in 17 cases (sensitivity: 89.4%); a positive culture was observed in two cases of pre-treated patients (sensitivity 10.5%). A false positive result was detected in the group of patients with non-meningococcal disease (specificity 98.5%). The application of this PCR permits a rapid (roughly 5 hours), specific and sensitive method that increases the microbiologic confirmation of meningococcal disease, mainly in patients who have received previous antibiotic treatment.

Perfil etiológico das meningites bacterianas em crianças

To determine the etiologic profile and analyze some epidemiological aspects of children with bacterial meningitis admitted to a public teaching hospital. A prospective study was conducted on children with clinical and laboratory diagnosis of bacterial meningitis, admitted to Hospital das Clínicas da Universidade Federal de Uberlândia, from January 1987 to January 2001. Patients with meningitis associated with trauma, intracranial devices or malformations of the neural tube, and tuberculosis, were not included in the study. From a total of 415 children with bacterial meningitis, the etiologic agent was detected in 315 (75.9%): Haemophilus influenzae b in 54.2%, meningococci in 20.6%, pneumococci in 18.1% and other agents, in 6.9%. Previous antibiotic treatment, observed in 47.2% of the cases, led to a significant decrease in positive blood cultures (from 50.8% to 38.7%) and in cerebrospinal fluid cultures (from 71.7% to 57.6%). Among children younger than 48 months Haemophilus influenzae b was predominant, particularly when compared to meningococci. The overall mortality was 10.1%, with a significant difference between the rates of pneumococcal (17.5%) and meningococcal meningitis (4.6%). Children affected by Haemophilus influenzae b and by pneumococci were younger than those with meningitis caused by meningococci. The blood and/or cerebrospinal fluid culture remains an important laboratory tool for etiologic diagnosis, despite the negative impact caused by antibiotic previous treatment. The agents most commonly detected were Haemophilus influenzae b, meningococci and pneumococci. Bacterial meningitis continues to present an important mortality among children, particularly when caused by pneumococci.

Detecting Helicobacter pylori infection in hospitalized frail older patients: the challenge.

Helicobacter pylori infection has not been well studied in older people, especially in hospitalized, frail patients. The aim of our study was to evaluate the prevalence of the infection in this population using five H. pylori diagnostic tests. Prospective observational study. Geriatric acute care unit of the Department of Geriatrics (Hôpital Xavier Arnozan, Pessac, France). One hundred seven consecutively hospitalized patients with a diagnostic indication for upper gastrointestinal endoscopy. Geriatric assessment, information on drug intake, indication/results of gastric endoscopy, and results of H. pylori infection diagnostic tests (culture and histological analysis on biopsy specimens, serology, 13carbon-urea breath test (13C-UBT), detection of H. pylori stool antigens (HpSA)) were assessed for each included patient. Fifty-one patients (47.7%) were H. pylori positive with at least one test. 13C-UBT was more frequently positive than the other four tests, with a significant difference from culture, histological analysis, and HpSA (P <.05). Positive 13C-UBT results were significantly associated with H. pylori presence using histological analysis and neutrophil activity of the antrum and corpus. Antibiotic treatments significantly decreased the positivity rate of all of the tests performed, and severe corpus atrophy decreased the positivity rate of culture, histological analysis, and HpSA. Almost one-third of the H. pylori-positive patients would have remained undetected without performing the 13C-UBT. The low prevalence of H. pylori detection in these hospitalized, frail patients may be explained by the high frequency of current and previous antibiotic treatments.

Characterisation of coagulase-negative staphylococci isolated from blood infections: incidence, susceptibility to glycopeptides, and molecular epidemiology.

The purpose of this study was to determine incidence of coagulase-negative staphylococci (CNS) bacteraemia and to characterise the epidemiology of isolates with reduced susceptibility to glycopeptides. CNS isolates from bloodstream infections were collected and characterised by determination of the species, analysis of antibiotic susceptibility, and restriction fragment length polymorphism using pulsed-field gel electrophoresis. The medical records of patients with positive cultures and the trends in glycopeptide use were reviewed to determine the effect of previous antibiotic treatment on the susceptibility profile of these organisms. The incidence of bacteraemia caused by CNS was 0.26 per 100 patients or 0.36 per 1,000 days of hospitalisation. According to genomic fingerprinting typing, 41 (67.2%) cases of bacteraemia were caused by a unique strain of CNS and 20 were caused by several strains. Nineteen of the 61 cases of bacteraemia studied were caused by an isolate with decreased susceptibility to teicoplanin. Genomic DNA analysis of the 90 CNS isolates recovered from the 61 cases of bacteraemia generated 50 unique profiles (1 isolate per major PFGE pattern) and 13 multiple profiles (several isolates per major PFGE pattern). Neither decreased susceptibility of an isolate to teicoplanin nor hospital acquisition was associated with a multiple profile. There was a significant correlation between the incidence of bacteraemia caused by CNS with decreased susceptibility to teicoplanin and glycopeptide use at the unit level but not in individual patients. Cross-transmission did not play an important role in the dissemination of CNS with decreased susceptibility to teicoplanin, thus strains probably become resistant as a result of antibiotic pressure. Prudent use of glycopeptides is necessary to minimise the spread of resistance to these agents.

Nosocomial outbreak of Serratia marcescens in a neonatal intensive care unit.

To investigate and describe an outbreak of Serratia marcescens in a neonatal intensive care unit (NICU) and to report the interventions leading to cessation of the outbreak. A 2,168-bed, tertiary-care, university teaching hospital in Vienna, Austria, with an 8-bed NICU. We conducted a case-control study to identify risk factors for colonization and infection with S. marcescens. A case-patient was defined as any neonate in the NICU with a positive culture for S. marcescens between October 1, 2000, and February 28, 2001. Polymerase chain reaction was applied to type isolates. During unannounced observations, the NICU was examined and existing policies were reviewed. Staff were reinstructed in hand antisepsis and gloving policies. Admissions were halted on December 27. During previously planned technical maintenance of the ward, the NICU was closed for 10 days and thorough aldehyde-based disinfection of the NICU was performed. Ten neonates met the case definition: 6 with infections (among them 3 with cerebral abscesses) and 4 with asymptomatic colonization. Previous antibiotic treatment of the mothers with cefuroxime was the single significant risk factor for colonization or infection (P = .028; odds ratio, 17; 95% confidence interval, 1.3 to 489.5). S. marcescens can cause rapidly spreading outbreaks associated with fatal infections in NICUs. With aggressive infection control measures, such outbreaks can be stopped at an early stage. Affected neonates themselves may well be the source of cross-infection to other patients on the ward. Antibiotic treatment of mothers should be reevaluated to avoid unnecessary exposure to antibiotics with the potential of over-growth of resistant organisms.

Bacteraemia caused by coagulase-negative staphylococci exhibiting decreased susceptibility to teicoplanin

The purpose of our study was to assess the prevalence of coagulase-negative staphylococci (CoNS) isolates with reduced susceptibility to glycopeptides among the isolates responsible for bloodstream infections and to describe the epidemiology of these isolates. CoNS isolates from bloodstream infections were collected and characterized by analysis of antibiotic susceptibility and restriction fragment length polymorphism using pulsed-field gel electrophoresis. The medical records of patients with positive cultures and trends in glycopeptide use were reviewed to determine the effect of previous antibiotic treatment on the susceptibility profile of these organisms. The crude incidence of CoNS bacteraemia was 0.51 per 1000 days of hospitalization. The 15 (28.8%) strains identified as having decreased susceptibility to teicoplanin by the reference method were all hospital-acquired and displayed 13 different DNA patterns. The relative risk of harbouring strains with decreased susceptibility to teicoplanin was 3.55 among patients previously treated with vancomycin (confidence interval 95%: 2.15–5.85). The teicoplanin consumption in our institution was constant and represented about 27% of the glycopeptide consumption in daily defined doses. The implementation of programmes aiming to reduce the unnecessary use of glycopeptides should have a significant impact on the reduced-susceptibility rate because strains probably become resistant as a result of antibiotic pressure.

Risk factors for nosocomial candidaemia: a case-control study in children

Candida spp. are increasingly important nosocomial pathogens in critically ill children. Data on risk factors of acquisition in children with candidaemia are limited. To determine the incidence, prognosis and risk factors for acquisition of nosocomial candidaemia in children, a prospective case-control study was performed between July 1998 and January 2000. Candidaemia was defined as the presence of at least one positive blood culture containing Candida spp. For each case, two controls were selected and matched for time and site of hospital admission. Logistic regression was used to obtain estimates of risk after simultaneous control for other variables. Candidaemia was diagnosed in 24 children (1.09/1000 admissions). The species most frequently isolated were Candida albicans (50%) and Candida parapsilosis (17%). Mean age was 58.2±58 months between cases and 41.8±52.2 months in controls (P not significant). The strongest risk factors for acquisition found in the univariate analysis were underlying disease, previous antibiotic treatment, the number of antibiotics administered, presence of a long-duration catheter and total parenteral nutrition (P<0.05). Sex, the site of hospital admission, artificial ventilatory assistance, transitory venous catheters, arterial and peripherally venous accesses, bladder catheter and transfusions were not statistically significant. The risk factors identified by multiple logistic regression analysis were: permanent catheter (OR 31.5; 3.19–310) and total parenteral nutrition (OR 10.5; 2.76–40.0). Nine (37%) children with nosocomial candidaemia and seven (15%) controls died (P=0.05). These findings should facilitate development of rational approaches to preventing infection and assist clinicians in identifying those patients in whom this life-threatening complication is likely to occur.

Prevalence of Neisseria meningitidis carriers in the school population of Catalonia, Spain.

The aim of this study was to determine the prevalence of healthy Neisseria meningitidis pharyngeal carriers in a representative sample of the Catalonian school population, as well as its associated factors. The sample was divided into age groups: < or = 5, 6-7 and 13-14 years old. Parents were given a questionnaire to collect information on sociodemographic and epidemiological variables. Oropharyngeal swabs were collected with a cotton-tipped swab in an Amies transport medium and cultured on Thayer Martin plates at 35 degrees C in 5% CO2. The isolates were serogrouped and sero/subtyped. Of the 1406 children studied, 75 (5.34%) meningococcal carriers were detected: 63 B (4.5%), 9 non groupable (0.7%), 2 29E (0.1%) and 1X (0.07%). No serogroup C meningococci were found in this study, probably due to the high A+C vaccination coverage of up to 68.9% in children 6-7 years old. Bivariate analysis identified six statistically significant risk factors for meningococcal carriage: increasing age, recent upper respiratory tract infection, previous antibiotic treatment, number of students in the class, size of the classroom and social class. Multivariate analysis found that only age and previous antibiotic treatment remained statistically significant when the other factors were controlled.

Détection et surveillance épidémiologique des résistances bactériennes aux antibiotiques en milieu communautaire

The monitoring of bacterial resistance to antibiotics in non-hospitalized patients is essential. More than 80% of antibiotics are prescribed in the community and many patients can carry multiresistant bacteria after hospitalization. In addition to its role in the diagnosis and assistance in the treatment of the community acquired infections, the biologist can integrate a surveillance network of bacterial resistance to antibiotics. This monitoring must consider historical and medical informations concerning the patients. Previous antibiotic treatment, or hospitalization are factors of major concern in the variation of resistance to antibiotics and species of the bacteria isolated from urinary tract infections in the community. Previous hospitalization is frequently found among patients carrying methicillin resistant Staphylococcus aureus. Recent antibiotic treatment is related to an important prevalence of Streptococcus pneumoniae presenting a decreased susceptibility to penicillin G. The notion of re-infection in often found when Haemophilus influenzae producing β-lactamase are isolated. The monitoring of the evolution of resistance to fluoroquinolones in Neisseria gonorrhoeae, and Salmonella Hadar and the survey of resistance to macrolides in β-haemolytic streptococci are also important objectives.

Two Controlled Trials of Antibiotic Treatment in Patients with Persistent Symptoms and a History of Lyme Disease

It is controversial whether prolonged antibiotic treatment is effective for patients in whom symptoms persist after the recommended antibiotic treatment for acute Lyme disease. We conducted two randomized trials: one in 78 patients who were seropositive for IgG antibodies to Borrelia burgdorferi at the time of enrollment and the other in 51 patients who were seronegative. The patients received either intravenous ceftriaxone, 2 g daily for 30 days, followed by oral doxycycline, 200 mg daily for 60 days, or matching intravenous and oral placebos. Each patient had well-documented, previously treated Lyme disease but had persistent musculoskeletal pain, neurocognitive symptoms, or dysesthesia, often associated with fatigue. The primary outcome measures were improvement on the physical- and mental-health-component summary scales of the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36)--a scale measuring the health-related quality of life--on day 180 of the study. After a planned interim analysis, the data and safety monitoring board recommended that the studies be discontinued because data from the first 107 patients indicated that it was highly unlikely that a significant difference in treatment efficacy between the groups would be observed with the planned full enrollment of 260 patients. Base-line assessments documented severe impairment in the patients' health-related quality of life. In intention-to-treat analyses, there were no significant differences in the outcomes with prolonged antibiotic treatment as compared with placebo. Among the seropositive patients who were treated with antibiotics, there was improvement in the score on the physical-component summary scale of the SF-36, the mental-component summary scale, or both in 37 percent, no change in 29 percent, and worsening in 34 percent; among seropositive patients receiving placebo, there was improvement in 40 percent, no change in 26 percent, and worsening in 34 percent (P=0.96 for the comparison between treatment groups). The results were similar for the seronegative patients. There is considerable impairment of health-related quality of life among patients with persistent symptoms despite previous antibiotic treatment for acute Lyme disease. However, in these two trials, treatment with intravenous and oral antibiotics for 90 days did not improve symptoms more than placebo.

Infective endocarditis in children — incidence, pattern, diagnosis and management in a developing country

Background: In developing countries, patients with infective endocarditis are referred late, there is low yield of blood cultures and incidence of rheumatic heart disease is still high. Objective: Evaluate clinical pattern, assess diagnostic criteria in our settings and determine outcome. Setting: A tertiary referral center for paediatric and adult cardiology. Patients and methods: All children with infective endocarditis admitted to a single center from April 1997 to March 2000 were analysed. The diagnosis was based on Duke’s criteria, which proposed two major and six minor criteria. Minor criteria were expanded to include raised acute phase reactants and presence of newly diagnosed or increasing splenomegally. The patients were stratified as definite, possible and rejected cases. Results: Of 1402 hospital admissions, 45 patients fulfilled the diagnostic criteria for infective endocarditis giving an incidence of 32 per 1000 hospital admissions. The mean age was 7.9±4 years (4 months to 16 years) with only two patients under 1 year of age. Rheumatic heart disease was the underlying lesion in 24 patients (53%) while congenital heart lesions occurred in 20 patients (45%). Previous antibiotic treatment was given in 26 patients (58%) definitely. Blood cultures were positive in 21 patients (47%); Streptococcus Viridans being the most common organism, while vegetations on echocardiography were present in 32 patients (71%). Surgery was undertaken in four patients and five patients left against medical advise. Of 10 patients with aortic valve involvement, there were three deaths (30%) and overall mortality was 13% (six patients). Conclusions: The incidence of infective endocarditis is 32 per 1000 (3.2%) hospital admissions in a tertiary paediatric cardiology referral center. Rheumatic heart disease is still the most common underlying heart lesion. Blood cultures are positive in less than 50% of cases and echocardiography in expert hands is a more sensitive tool in our set up. Mortality is still high and aortic valve involvement in particular, carried poor prognosis.

Comparative analysis of outcome and clinical features in children with pleural empyema caused by penicillin-nonsusceptible and penicillin-susceptible Streptococcus pneumoniae

Objective: To describe the clinical characteristics of pleural empyema in children caused by Streptococcus pneumoniae nonsusceptible to penicillin and compare their clinical outcome with pleural empyemas caused by penicillin-susceptible organisms. Methods: Records of 109 children with complicated pleural effusions between January 1996 and December 1998 were retrospectively reviewed. Results: Pathogens were recovered in 45 of these cases. Streptococcus pneumoniae represented 71 % of the isolates, with 20 (62%) and 12 (38%) of the strains proving susceptible and non-susceptible to penicillin, respectively. The average age for children with penicillin-nonsusceptible infections was 18.3 months compared with an average age of 40.9 months for those with penicillin-susceptible infections (P = 0.03). Previous antibiotic treatment was more frequent in children with penicillin-non-susceptible organisms (P = 0.05). No significant differences were found between the two groups for gender, underlying diseases, duration of fever and tachypnea, need of surgical treatment, bacteremia incidence, mean duration of therapy, or length of hospital stay. Conclusions: Pleural empyemas caused by penicillin-nonsusceptible S. pneumoniae appear to be associated with younger age and previous antibiotic treatment. By contrast, the outcome was not influenced by the penicillin susceptibility of the pneumococcus strains.

Diagnosis of pneumonia and monitoring of infection eradication.

Pneumonia can be classified as community-acquired (CAP) or hospital-acquired (nosocomial). Both are frequent infections that demand a great amount of medical resources. The diagnosis of CAP is based on clinical signs and the presence of a pulmonary infiltrate visible on chest radiograph. For practical purposes, CAP has been classified as typical, with an acute onset in which the most representative microorganism is Streptococccus pneumoniae, and atypical, with a subacute onset (Mycoplasma pneumoniae). Nevertheless, so far no studies have clearly demonstrated the utility of this classification in predicting the aetiology. Guidelines on CAP recommend associating the aetiology of CAP with comorbidity, age and severity. The microbiological diagnosis relies mainly on Gram stain and sputum culture, but this technique has disadvantages such as frequent contamination of the sample with oropharyngeal commensal flora, frequent sterile cultures associated with previous antibiotic treatment, and the fact that approximately 40% of patients are not able to expectorate. Other diagnostic techniques such as blood cultures, serological tests and fibreoptic bronchoscopy must be reserved for patients who are hospitalised, especially if they need admission to an intensive care unit. Compared with CAP, nosocomial pneumonia has major diagnostic problems due to the presence of other diseases able to mimic pneumonia and frequent bacterial colonisation of the lower respiratory tract. Most of the diagnostic techniques produce a high percentage of false-negative and false-positive results. This is especially true for ventilator-associated pneumonia. There is controversy over using a comprehensive aetiological work-up based on bronchoscopic techniques or only on quantitative culture of endotracheal aspiration. By contrast, there is consensus about the importance of the adequacy of empirical antibiotic treatment, since mortality rates are higher in patients who are inadequately treated. Once treatment of pneumonia has begun, it must be maintained for 48 to 72 hours because this is the minimum time to evaluate a clinical response. Antibacterial agents have to be adjusted according to microbiological findings. In nonresponding patients, pneumonia-related complications and the presence of multiresistant micro-organisms or non-covered pathogens must be ruled out.

Value of gram stain examination of lower respiratory tract secretions for early diagnosis of nosocomial pneumonia.

Except for bronchoalveolar lavage, the value of the Gram stain examination of respiratory tract samples for the diagnosis of hospital-acquired pneumonia (HAP) and their potential impact on empiric antibiotic treatment have rarely been assessed. During a 14-mo period, both plugged telescoping catheter (PTC) and endotracheal aspirate (EA) were performed when an HAP was suspected in mechanically ventilated patients. The results of Gram stain examinations and cultures and previous and subsequent antibiotic treatment were prospectively recorded. Two criteria for pneumonia were considered: (1) clinically diagnosed pneumonia, according to attending physicians, based on clinical and radiological evolution and the PTC culture results, and (2) microbiologically proven pneumonia (solely based on the result of quantitative PTC culture). Of 91 episodes of suspected HAP in 51 patients, 27 (30%) episodes were clinically diagnosed as pneumonia. When considering clinically diagnosed pneumonia, the sensitivity and specificity of Gram stain examination were similar (respectively, 89% and 62% for EA and 67% and 95% for PTC). When considering microbiologically proven pneumonia, the sensitivity and specificity of Gram stain examination were, respectively, 91% and 64% for EA and 70% and 96% for PTC. The negative predictive value of Gram stain examination of EA and the positive predictive value of Gram stain examination of PTC were high. Our results suggest that the combination of Gram stain examination of paired PTC and EA may contribute to the early diagnosis of HAP in about two-thirds of mechanically ventilated patients, and guide the empiric therapy when needed. In the remaining one-third of patients, the Gram stain examination is not helpful in predicting HAP.