Emerging non-13-valent pneumococcal conjugate vaccine (PCV13) serotypes causing adult invasive pneumococcal disease in the late-PCV13 period in Spain

OBJECTIVE

An early reduction of adult invasive pneumococcal disease (IPD) was observed after the 13-valent pneumococcal conjugate vaccine (PCV13) introduction for children in Spain. We analysed the epidemiology of adult IPD in the late-PCV13 period.

METHODS

This was a prospective multicentre study of adult IPD involving six hospitals. Strains were serotyped, genotyped and studied for antimicrobial susceptibility. The late-PCV13 period was compared with the pre- and early-PCV13 periods.

RESULTS

A total of 2197 episodes were collected-949 in 2008-2009, 609 in 2012-2013 and 639 in 2015-2016. The initial decrease of IPD observed (from 12.3/100 000 to 8.1/100 000; 2008-2009 versus 2012-2013) plateaued in 2015-2016 (8.3/100 000). IPD due to PCV13 serotypes decreased (from 7.7 to 3.5 to 2.3/100 000; p < 0.05), whereas IPD caused by non-PCV13 serotypes increased (from 4.5 to 4.6 to 6.0/100 000; p < 0.05). The most frequent serotypes in the late-PCV13 period were: 8 (15.1%), 3 (10.5%), 12F (7.9%) and 9N (5.4%). These serotypes were related to major genotypes: CC53 (59.8%) and CC404 (30.4%) for serotype 8, CC180 (64.1%) and CC260 (28.1%) for serotype 3, CC989 (91.7%) for serotype 12F and CC67 (84.8%) for serotype 9N. Penicillin-non-susceptibility (21.2%) was associated with serotypes 11A (CC156), 14 (CC156) and 19A (CC320), and macrolide-resistance was related to serotypes 24F and 19A. Rates of pneumococcal meningitis remained stable throughout the periods (ranges 0.9, 0.8 and 1.0/100 000).

CONCLUSIONS

The initial decrease of adult IPD observed after PCV13 introduction for children has been balanced by the rise of non-PCV13 serotypes. The spread of antibiotic-resistant lineages related to non-PCV13 serotypes (11A and 24F) could be a threat for the treatment of serious pneumococcal diseases.

Evolution over a 15-year period of the clinical characteristics and outcomes of critically ill patients with severe community-acquired pneumonia

OBJECTIVES

To study the characteristics and outcomes of patients in the ICU with severe community-acquired pneumonia (SCAP) over a 15-year surveillance period.

METHODS

We conducted a retrospective cohort study of episodes of SCAP, and assessed the epidemiology, etiology, treatment and outcomes of patients admitted to the ICU, comparing three periods (1999-2003, 2004-2008 and 2009-2013).

RESULTS

A total of 458 patients were diagnosed with SCAP. The overall cumulative incidence was 37.4 episodes/1000 admissions, with a progressive increase over the three periods (P<0.001). Patients fulfilling the two major IDSA/ATS criteria at admission increased from 64.2% in the first period to 82.5% in the last period (P=0.005). Streptococcus pneumoniae was the prevalent pathogen. The incidence of bacteremia was 23.1%, and a progressive significant reduction in overall incidence was observed over the three periods (P=0.02). Globally, 91% of the patients received appropriate empiric antibiotic treatment, increasing from 78.3% in the first period to 97.7% in the last period (P<0.001). Combination antibiotic therapy (betalactam+macrolide or fluoroquinolone) increased significantly from the first period (61%) to the last period (81.3%) (P<0.001). Global ICU mortality was 25.1%, and decreased over the three periods (P=0.001).

CONCLUSIONS

Despite a progressively higher incidence and severity of SCAP in our ICU, crude ICU mortality decreased by 18%. The increased use of combined antibiotic therapy and the decreasing rates of bacteremia were associated to improved patient prognosis.

Prospective Randomized Trial of 3 Antiseptic Solutions for Prevention of Catheter Colonization in an Intensive Care Unit for Adult Patients

Objective.

To compare the effectiveness for prevention of central venous and arterial catheter colonization of 3 skin antisepsis with 1 of 3 antiseptic solutions: 10% aqueous povidone iodine (aqueous PI), 2% aqueous chlorhexidine gluconate (aqueous CG), and 0.5% alcoholic chlorhexidine gluconate (alcoholic CG).

Design.

Prospective, randomized controlled trial.

Setting.

Intensive care unit in a teaching hospital.

Methods.

Patients were randomly assigned to 1 of the 3 skin antisepsis groups. The distal tips of catheters were semiquantitatively cultured when the catheters were no longer necessary or if there was a suspicion of catheter-related infection. Rates of catheter colonization, catheter-related sepsis, and catheter-related bacteremia were compared among the 3 groups.

Results.

A total of 631 catheters were included in the study (194 from the aqueous PI group, 211 from the aqueous CG group, and 226 from the alcoholic CG group). The incidence of catheter colonization was significantly lower in the alcoholic CG than in the aqueous PI group (14.2% vs 24.7%; relative risk, 0.5 [95% confidence interval, 0.3-0.8; P < .01]); it was also significantly lower in the aqueous CG group than in the aqueous PI group (16.1 % vs 24.7%; relative risk, 0.6 [95% confidence interval, 0.4-0.9; P = .03]). There were no significant differences between the aqueous CG and the alcoholic CG groups. Incidences of catheter-related bacteremia were similar for all 3 groups. The aqueous and alcoholic CG solutions were superior to the aqueous PI solution in preventing catheter colonization due to gram-positive bacteria.

Conclusions.

The aqueous and alcoholic CG solutions for cutaneous antisepsis were similarly effective in preventing colonization of central venous catheters and arterial catheters. Both had significantly lower incidences of colonization than did the aqueous PI solution; this effect seems to be related to the CG solutions' more efficacious prevention of colonization with gram-positive bacteria.

Differential time to positivity of blood cultures: a valid method for diagnosing catheter-related bloodstream infections in the intensive care unit

PURPOSE

The validation in critical patients with short-term catheters of a method for diagnosing catheter-related bloodstream infection (CR-BSI), based on the differential time to positivity (DTP) of blood cultures.

METHODS

Patients suspected of having CR-BSI were included. Two peripheral vein blood cultures and a catheter hub blood culture were simultaneously carried out. The responsible catheter was removed and tip cultured. Times to positivity of all blood cultures were automatically registered. CR-BSI was diagnosed when all the cultures were positive for the same microorganism and DTP≥120 min. This diagnosis was compared with the one obtained using the standard method.

RESULTS

226 cases suspected of CR-BSI were analyzed during a 20-month period. A total of 19 removed catheters were associated with CR-BSI. Seven cases of polymicrobial cultures (4 with CR-BSI) were discarded from the final analysis due to the impossibility of determining the time to positivity for each individual microorganism. Using the DTP method, 12 out of 15 CR-BSI cases were diagnosed (sensitivity 80%, specificity 99%, PPV 92%, NPV 98%). In a ROC curve, we found a cut-off value of 17.7 h in positivity of hub blood cultures that may be useful for diagnosing CR-BSI.

CONCLUSION

DTP can be a valid method for CR-BSI diagnosis in critically ill patients, avoiding unnecessary catheter withdrawal.

Influence of pneumococcal serotype group on outcome in adults with bacteraemic pneumonia

The influence of infecting serotype group on outcome in bacteraemic pneumococcal pneumonia remains unclear. We performed a prospective, 10-yr observational study in an 800-bed teaching hospital. 299 adults diagnosed with pneumonia whose blood cultures showed growth of Streptococcus pneumoniae were included in the study. High invasive disease potential (H) serotypes included serotypes 1, 5 and 7F, which served as a reference category, were compared with low invasive disease potential (L) serotypes (3, 6A, 6B, 8, 19F, and 23F) and other (O) serotypes (non-H, non-L). The influence on outcome was determined for each group of serotypes after adjusting for underlying conditions and severity of illness at admission. Overall, 30-day mortality was 11%. H serotypes (n = 93) infected primarily younger people and presented a higher risk of complicated parapneumonic effusion or empyema (17.2 versus 5.1%; p = 0.01), with lower mortality (3.2%). The isolation of L serotypes (n = 78) was an independent risk factor for 30-day mortality (OR 7.02, 95% CI 1.72-28.61), as were Charlson score (OR 1.30, 95% CI 1.08-1.58), alcohol abuse (OR 3.99, 95% CI 1.39-11.39) and severity of illness measured by American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) criteria (OR 4.80, 95% CI 1.89-12.13). A vaccination strategy including serotypes 3, 6A, 6B, 8, 19F and 23F may improve survival in adults.

[An outbreak of gram-negative bacteremia (GNB), especially enterobacter cloacae, in patients with long-term tunnelled haemodialysis catheters]

Vascular access through a venous catheter for haemodialysis is associated with increased risk of thrombosis, central venous stenosis, short access survival and inadequate dialysis. The most important catheter-related complications, which determine method survival, are infection and dysfunction. In particular, infectious episodes are in some studies the leading cause for untimely catheter removal and for catheter-related morbidity but also for morbidity in dialysis patients. Double-lumen central venous catheters used for haemodialysis, are common causes of septicaemia. Most cases are caused by staphylococci. Episodes of gram-negative bacteriemia have been traced to bacterial contamination of water and/or dialysate, errors in dialyzer reprocessing, and improper setup procedures. In this paper, we describe and outbreak of gram-negative bacteremia, firstly E. cloacae, in an outpatients haemodialysis unit, in the patients with long-term tunnelled haemodialysis catheters. We describe the epidemic investigation that we achieved to identify the source of contaminating bacteria and the route by which bacteria gained access to the bloodstream. We prove the contamination by gram-negative bacterium of the water-distribution lines and haemodialysis machines. Moreover, E. cloacae strains isolated from the lines and machines are genotypically identical to the isolated from the patients. Also, we prove that the hands of health care personnel are unintentional carriers. The outbreak was finished when decontamination of dialysis machines was enhanced and dialyzer-priming fluid was modified.

Epidemiology of invasive Streptococcus pneumoniae infections in children in an area of Barcelona, Spain

AIM

Streptococcus pneumoniae is the most common cause of bacteraemia, pneumonia, sinusitis and acute otitis media. With the advent of conjugate vaccines, there is now the possibility of preventing disease caused by this organism. However, little is known about the epidemiology of invasive pneumococcal disease in children in Spain. The aim of this study was to determine the incidence and the clinical and microbiologic characteristics of invasive pneumococcal disease in Sabadell, an industrial area in the province of Barcelona, Spain.

METHODS

From January 1990 to December 2000, the case records of children with pneumococcal invasive disease at Sabadell Hospital were retrospectively (1990-1996) reviewed and prospectively (1997-2000) collected. The hospital serves a population of 61,143 children under 15 y of age, 18,073 children under 4 y of age and 7300 children under 2 y of age.

RESULTS

A total of 112 children (54% under 24 mo of age and 93% under 6 y of age) with invasive pneumococcal disease were diagnosed during a period of 11 y. The incidence of invasive pneumococcal disease was 76 per 100,000 for children aged 0 to 24 mo, 45 for children aged 0-48 mo and 16.6 for children aged 0-14 y. Occult bacteraemia was the most common manifestation of invasive pneumococcal disease (66 cases), pneumonia was the second form (34 cases) and meningitis (10 cases) and arthritis (2 cases) were the other clinical manifestations. Of the 105 strains tested, 8.6% were highly penicillin resistant, 37.1% were intermediately penicillin resistant. 16.2% were intermediately cefotaxime resistant and 32.4% were erythromycin resistant. Pneumococci of serogroups 6, 14, 18, 19, 1, 5, 4, 9, 23 and 33 were the most frequently isolated groups (92%) but only 6, 9, 14, 19 and 23 were resistant to penicillin, cefotaxime, or erythromycin.

CONCLUSIONS

In this study the incidence of invasive pneumococcal disease was found to be greater than that reported elsewhere in Spain and Europe. Penicillin resistance levels are high but the trend towards increasing penicillin resistance may have ended over the past few years. The currently licensed seven-valent (7-V) pneumococcal conjugate vaccine would cover 78% of cases of invasive pneumococcal in children aged 0-14 y, 80% in children aged 0-24 mo and 100% of cases of penicillin- or cefotaxime-resistant invasive pneumococcal disease.

Association between asymptomatic carriage and sporadic (endemic) meningococcal disease in an open community

We analysed a strain collection representative of the overall Neisseria meningitidis population circulating in an open community (46,000 inhabitants, Spain) during an endemic period (30 isolates from patients and 191 from throat cultures of healthy individuals) by both phenotypic and molecular techniques. Almost all patient isolates were assigned to three hyper-virulent lineages (ET-5 complex, ET-37 complex and cluster A4) by both multilocus enzyme electrophoresis (MEE) and pulsed-field gel electrophoresis (PFGE). In contrast, MEE and PFGE assigned 20% and 15% respectively of carrier isolates to the hyper-virulent clones (4% for both methods together). There was also a higher correlation between PFGE and phenotypes associated with virulent clones. These notable differences between the two molecular methods were further observed in more than half the carrier isolates, suggesting that the associations between these strains were distorted by recombination events. However, almost one-third of total endemic strains from symptom-free carriers and almost all patient strains belonged to clones defined by MEE and PFGE, with no known epidemiological connection. These data indicate low transmission and a weak clonal structure for N. meningitidis.

Eleven-year study of recurrent pneumococcal bacteremia

In order to describe the epidemiology and the clinical and microbiological manifestations of recurrent pneumococcal bacteremia, a long-term study was conducted. Between January 1988 and December 1998, a total of 344 episodes of bacteremia caused by pneumococci was detected in 331 patients. Thirteen (3.9%) of these patients experienced recurrent episodes of pneumococcal bacteremia, and all of them had underlying diseases. In 12 of these patients the recurrence was considered to be a reinfection, and in one patient it was considered to be a relapse. Three patients were found to harbor identical strains in both bacteremic episodes, as determined by pulsed-field techniques. Only hematological neoplasia appeared to be a predisposing factor for recurrent pneumococcal bacteremia.

Prevalence of Haemophilus influenzae pharyngeal carriers in the school population of Catalonia. Working Group on invasive disease caused by Haemophilus influenzae

The objective of this study was to determine the prevalence of healthy Haemophilus influenzae (Hi) pharyngeal carriers in a representative sample of the Catalonian school population, as well as the factors associated. A two-stage cluster sampling was carried out. Parents were given a questionnaire to collect information on sociodemographic and epidemiological variables. A pharyngeal swab was performed on children when informed consent was given by parents, and was cultured on chocolate agar with 260 microg/ml bacitracin. Of the 1212 children studied, 316 (26%) H. influenzae carriers were detected: 5 (0.4%) serotype b, 1 (0.08%) serotype c, 6 (0.5%) serotype e, 5 (0.4%) serotype f, and 299 (24.7%) non-typable. Age, gender and geographical location were the only variables associated with H. influenzae carrier status. The prevalence of non-typable H. influenzae carriers was similar to that of studies carried out in other countries, while that of serotype b carriers was similar to the remainder of H. influenzae capsulates, and lower than that described in previous studies. These data are in accordance with the low incidence of the disease observed in our context, although the possibility that the vaccine coverage may have affected the results of this study cannot be dismissed.

Prevalence of Haemophilus influenzae carriers in the Catalan preschool population. Working Group on Invasive Disease Caused by Haemophilus influenzae

This study was designed to determine the prevalence of healthy Haemophilus influenzae carriers in a random sample of the preschool population in Catalonia. Oropharyngeal swabs were collected and cultured on chocolate agar supplemented with 260 microg/ml of bacitracin. Four hundred two of the 734 (54.8%) children studied were detected as Haemophilus influenzae carriers: 7 (0.9%) carried serotype b, 14 (1.9%) serotype e, 6 (0.8%) serotype f, and 375 (51%) carried nontypable strains. The results show that, although the prevalence of Haemophilus influenzae carriers is similar to figures reported from other countries, the prevalence of Haemophillus influenzae serotype b carriers is lower and corresponds with the low incidence of invasive disease observed in the Catalan community.

Comparison of conventional ribotyping and PCR-RFLP ribotyping for the analysis of endemic strains of Neisseria meningitidis isolated in a local community over 7 years

Conventional ribotyping was compared with the PCR amplification of the intergenic spacer region between 16S and 23S rRNA genes (PCR-RFLP ribotyping) when applied to the subtyping of sporadic Neisseria meningitidis strains. Thirty isolates out of a total of 36 meningococcal disease cases, reported as having occurred in a particular community over a 7-year endemic period, were analyzed by each of the methods. Only ribotyping with three restriction enzymes (EcoRI, ClaI and XhoI) gave acceptable discriminatory power for short-term epidemiological purposes. We conclude that conventional ribotyping is a suitable method for typing sporadic meningococcal strains and that it cannot be replaced by the more straightforward PCR-RFLP ribotyping method.

[Haemophilus influenzae type b invasive disease in Catalonia (1996)]

BACKGROUND

The purpose of this study was to find out the incidence and characteristics of H. influenzae type b invasive disease (HibID) in Catalonia, Spain.

MATERIAL AND METHODS

An active surveillance of H. influenzae isolated from normally sterile sites was carried out during 1996. Microbiology laboratories of hospitals of Catalonia were periodically contacted by telephone. The serotype of all the strains was studied.

RESULTS

The incidence of H. influenzae invasive disease (HIID) was 7.1 per 100,000 in children under 5 years and 1.0 per 100,000 in those over 5 years. The incidence of serotype b was 6.4 per 100,000 children under 5 years and 0.2 above this age. Only three strains belonged to types other than b (d, e and f).

CONCLUSIONS

The incidence of HIbID is uncommon in Catalonia, lower than that registered in the prevaccine era in other countries and regions of the same geographical area.

[Evaluation of the polymerase chain reaction technique for the diagnosis of meningitis caused by Neisseria meningitidis and Haemophilus influenzae]

BACKGROUND

Bacterial meningitis is a severe infection of the central nervous system (CNS), most frequently caused by Neisseria meningitidis in our setting. Microbiologic diagnosis of bacterial meningitis is not enough sensitive because its efficiency can be affected by the therapeutic regimen given to the patient. Polymerase chain reaction (PCR) can provide a more sensitive diagnosis and allow us to get an earlier result.

OBJECTIVES

To assess the sensitivity and specificity of a PCR technique for the diagnosis of meningitis caused by N. meningitidis and Haemophilus influenzae.

MATERIAL AND METHODS

Ninety-six patients who were attended because of suspected bacterial meningitis on the Hospital de Sant Joan de Déu, Corporació Sanitària Parc Taulí and Hospital de la Santa Creu i Sant Pau, and had negative results by conventional laboratory methods, were selected for the study. A total of 99 cerebrospinal fluid samples (CSF) were obtained and evaluated for PCR. DNA extracts of the CSF samples were amplified by universal primers. Amplification products were hybridized with specific probes for Haemophilus genus and N. meningitidis. Positive and negative controls were included to asses the reliability of PCR.

RESULTS

Eight of the 99 CSF samples (8%) were positive by PCR and subsequent hybridization with the specific probe of N. meningitidis. None of the amplicons hybridized with the probe of Haemophilus genus. Thirteen percent of the patients (8/59) with clinical suspicious of non-neonatal sepsis or meningitis were diagnosed by PCR, amongst them, 36% of the cases (4/11) with initial diagnosis of meningococcal sepsis or meningitis.

CONCLUSIONS

The sensitivity and the specificity of the PCR technique afford a complementary method to conventional ones, in special for the diagnosis of meningococcal meningitis in the group of pediatric patients.

Antimicrobial use in patients with positive intravascular catheter cultures: a six-month prospective survey in a teaching hospital

Review of medical records revealed that, of 190 intravascular catheters sent for culture during the study period, 50 were positive. Of these 50, 11 (22%) were sent for culture as a routine procedure without special clinical indications. Of the remaining 39 cultures, only 11 (28%) had clinical impact in the patient's management. Ten of the 50 therapeutic interventions were inappropriate. Restricting cultures to patients who may have catheter-related infection is likely to lead to significant cost savings.

[Prevalence of nosocomial urinary infection. Alternatives to bladder catheterization]

BACKGROUND

The detection of a high percentage of nosocomial urinary infection (NUI) associated with vesical catheterization (VC) and the frequent use of VC in patients with urinary incontinence, led us to implant a prevention programme which included the introduction of absorbent diapers as a alternative to vesical catheterization in incontinent patients.

MATERIAL AND METHODS

After actualization and introduction of VC preventive measures and the introduction of absorbent diapers, regular determinations were made of the prevalence of NUI with analysis of the variations using the chi 2 test for trends. The prevalence of urinary incontinence and the efficacy of the diapers were also measured.

RESULTS

The prevalence of NUI associated with VC showed a significant decrease, from 27.5% to 3% (p = 0.004). Between 6% and 11% of the patients admitted to the medical service had urinary incontinence. After introduction of the diapers as part of health care assistance programme, the use of VC in patients with urinary incontinence is rare.

CONCLUSIONS

1) The prevention programme allowed a significant reduction in the prevalence of NUI associated with VC. 2) The use of absorbent diapers to care for patients with urinary incontinence probably contributed to reducing the prevalence of NUI. It was well accepted by the nursing staff and iatrogeny associated with their use was scarce.

Impact of using an indwelling introducer on diagnosis of Swan-Ganz pulmonary artery catheter colonization

A prospective study was conducted to determine how the use of an indwelling introducer influences the diagnosis of pulmonary artery catheter (PAC) colonization. Sixty-six consecutive PACs and introducers were aseptically removed over a 15-month period. Two segments of the catheter and the catheter tip (a proximal segment from the portion of the catheter beneath the introducer) and two segments of the introducer (a proximal intradermal segment and the introducer tip) were cultured using a semiquantitative technique. Nineteen of 66 (28.7%) PACs showed colonization, representing an incidence of 5.6 episodes per 100 catheterization-days. Catheter tip cultures identified only 68% of colonized PACs; this yield rose to 91% when introducer tip cultures were added. These results indicate a need to evaluate both introducer tip cultures and catheter tip cultures for an accurate diagnosis of PAC colonization when an indwelling introducer is used.

Lower respiratory tract infections following cardiac arrest and cardiopulmonary resuscitation

All episodes of lower respiratory tract infection that developed among 96 patients surviving for > 24 hours after cardiac arrest were prospectively studied over an 18-month period. Pneumonia developed in 23 (24.0%) of patients after a mean of 7 days (SD, +/- 6.2 days). The development of four superinfections raised the cumulative incidence to 28.1%. Purulent tracheobronchitis was diagnosed in three instances. The causative agent of pneumonia was identified in 18 episodes, three of which were polymicrobial. Gram-positive cocci represented 57.1% of isolates, and Staphylococcus aureus--the most frequently isolated microorganism in this population--accounted for two-thirds of all gram-positive cocci. Pseudomonas aeruginosa was isolated in six episodes, five of which were associated with previous antibiotic use. Nine (39.1%) of the 23 patients in the group with pneumonia died, but only one of these deaths was considered to be directly related to pneumonia. In conclusion, pneumonia is a common complication of patients surviving cardiac arrest, but, with adequate treatment, its influence on outcome is marginal. Gram-positive cocci are the predominant pathogens, although infection with P. aeruginosa should be considered among patients receiving antibiotics.

[Prevalence of Neisseria meningitidis carriers among the population of Cerdanyola (Barcelona)]

OBJECTIVE

To determine the prevalence of Neisseria meningitidis (N. meningitidis) from healthy carriers and its resistance to penicillin in Cerdanyola population. To asses which risk factors were associated with healthy carriers and compare some epidemiologic characteristics between people with penicillin sensitive and penicillin resistant strains.

METHODS

Cross-sectional seasonal study of 1500 individuals selected from day care centers, schools, colleges, cultural and working centers, located in different areas of Cerdanyola. We performed throat smears and immediate culture onto selective media for isolation of N. meningitidis. Data were evaluated by univariate and multivariate statistical analysis using the SPSS statistical package.

RESULTS

One hundred and ninety-one (12.7%) individuals harbored N. meningitidis strains. In logistic regression multivariate analysis, meningococcal carriage significantly increased for the age group 14-18 years (OR = 4.55 with respect to the reference group, 0-3 years), in the spring (OR = 2.29), male sex (OR = 1.67), and active smoking (OR = 1.45, intervals of 10 cigarettes/day), while meningococcal carriage significantly decreased in the group under 4 years at age (OR = 0.55), with prior use of antibiotics (OR = 0.58) and with bigger housing space (OR = 0.84 for 10 m2/person). A 42% of N. meningitidis strains in carriers from this population showed decreased sensitivity to penicillin (MIC > 0.1 microgram/ml). We have not found significantly association between the variables studied and penicillin resistance among carriers of N. meningitidis.

CONCLUSIONS

Age, spring season, sex, active smoking and overcrowded housing are significantly associated to carrier state. Prior use of antibiotics decreased to carrier state. According to our findings, reducing smoking habits and improving housing conditions may be useful measures to reduce the prevalence of carriers.

Continuous aspiration of subglottic secretions in preventing ventilator-associated pneumonia

OBJECTIVE

To determine whether continuous subglottic aspiration prevents nosocomial pneumonia in mechanically ventilated patients.

DESIGN

A randomized, controlled, blinded study.

SETTING

Medical-surgical intensive care unit.

PATIENTS

190 patients who were admitted to the intensive care unit during a 33-month period and whose condition suggested the need for prolonged intubation (> 3 days).

INTERVENTION

76 patients were randomly allocated to receive continuous aspiration of subglottic secretions, and 77 control patients were allocated to receive usual care.

MEASUREMENTS

The numbers of cases of ventilator-associated pneumonia, ventilated days, days in intensive care unit, and deaths were recorded. The amount of subglottic secretions aspirated daily and surveillance cultures in the subglottic secretions were also obtained periodically. Etiologic diagnosis was based on the quantitative culture of secretions obtained by protected specimen brush or bronchoalveolar lavage.

RESULTS

The incidence rate of ventilator-associated pneumonia was 19.9 episodes/1000 ventilator days in the patients receiving continuous aspiration of subglottic secretions and 39.6 episodes/1000 ventilator days in the control patients (relative risk, 1.98; 95% CI, 1.03 to 3.82). This difference was due to a significant (P < 0.03) reduction in the number of gram-positive cocci and Haemophilus influenzae organisms in the patients receiving continuous aspiration. However, no differences were observed in the number of Pseudomonas aeruginosa or Enterobacteriaceae organisms. Episodes of ventilator-associated pneumonia occurred later in patients receiving continuous aspiration (12.0 +/- 7.1 days) than in the control patients (5.9 +/- 2.1 days) (P = 0.003). The same microorganisms isolated from protected specimen brush or bronchoalveolar lavage cultures in patients with ventilator-associated pneumonia were previously isolated from cultures of subglottic secretions in 85% of cases. No significant differences in outcome were found.

CONCLUSIONS

The incidence of nosocomial pneumonia in mechanically ventilated patients can be significantly reduced by using a simple method that decreases the chronic microaspirations through the cuff of endotracheal tubes.

Predictive factors for invasive disease due to penicillin-resistant Streptococcus pneumoniae: a population-based study

A prospective population-based study was carried out to determine predictive factors associated with penicillin-resistant pneumococcal invasive disease. A total of 374 patients (250 males and 124 females; mean age, 50.3 +/- 27 years) with invasive pneumococcal infection were admitted to one of the five hospitals in El Vallés County (an industrial area with 800,000 inhabitants in the province of Barcelona, Spain) over a period of 5 years. Of the 374 episodes, 21 (5.6%) were due to highly penicillin-resistant pneumococci and 67 (17.9%) to intermediately penicillin-resistant pneumococci. Multivariate analysis showed a statistically significant association between infection with intermediately penicillin-resistant pneumococci and an age of 0-4 years (odds ratio [OR] = 5.3; 95% confidence interval [CI] = 2.2-12.6), the presence of an immunosuppressive underlying disease (OR = 3.0; 95% CI = 1.5-6.0), and the previous use of beta-lactam antibiotics (OR = 2.1; 95% CI = 1.0-4.5). Infection with highly penicillin-resistant pneumococci was associated only with the previous use of beta-lactam antibiotics (OR = 5.9; 95% 95% CI = 2.2-15.8). Highly resistant strains were of serotypes 6, 9, 14, 15, 19, and 23, of which all but serotypes 9 and 15 are included in the newly formulated conjugated vaccine.

Meningococcal meningitis with 'normal' cerebrospinal fluid

A prospective study was made of all patients with normal CSF counts and positive cultures for Neisseria meningitidis diagnosed in "El Vallés" County, Barcelona between January 1987 and December 1990. Meningococcal meningitis was documented in 82 patients, eight of whom (seven children, five boys and two girls with a mean age of 5.6 +/- 3.3 years, and a 69-year-old male patient) had no apparent CSF abnormalities in the initial lumbar puncture. At the time of admission all patients had fever (mean 39.1 degrees C) of 10.8 +/- 5.6 hour duration and petechial rash which had been present for a mean of 3.6 +/- 3.3 hours. Signs of meningeal irritation were not found. A 4-month-old infant with symptoms of circulatory collapse, intracranial hypertension and impairment of consciousness subsequently died of septicemia in 48 hours. Group B N. meningitidis was isolated in six cases (reduced penicillin-susceptibility in two cases) and group C N. meningitidis in the remaining two (reduced penicillin-susceptibility in one case). Patients without pleocytosis did not differ in a statistically significant fashion from the patients with high pleocytosis in the duration of temperature, and petechial rash, leukopenia, positive blood culture and fatal outcome.

Prospective epidemiological study of invasive Haemophilus influenzae disease in adults

The incidence and characteristics of invasive Haemophilus influenzae disease were studied in 43 adult patients admitted to the acute care hospitals in El Vallés County (Barcelona, Spain) between January 1987 and June 1992. The annual incidence of Haemophilus influenzae disease was 1.2 per 100,000 inhabitants. Pneumonia occurred in 24 patients, meningitis in five, intraabdominal infections in three, obstetric infections in two, epiglottitis in two and cellulitis in one. In six patients the source of infection was unknown. Ten (23%) of the infections were hospital acquired. Underlying conditions were diagnosed in 30 (70%) patients. Nontypeable Haemophilus influenzae strains predominated in all adult age groups. Sixty-one percent of type b and 34% of nontypeable strains were ampicillin resistant (p = 0.08). Multiple antibiotic resistance was also high among type b (53%) and nontypeable (18%) strains. The mortality rate was significantly higher in patients with pneumonia, bacteremia from an unidentified focus or shock at presentation.

[Characterization of Haemophilus influenzae's resistance to ampicillin]

BACKGROUND

The resistance of Haemophilus influenzae to ampicillin is nearly always dependent on plasmid-mediated betalactamase production. The betalactamase type most frequently identified was TEM-1; type ROB has occasionally been identified. The presence of plasmid-mediated betalactamase has been studied in H. influenzae strains moderately susceptible or resistant to ampicillin.

METHODS

The test used in the detection of the presence of betalactamase was nitrocefin hydrolysis; the enzyme type was identified by analytic isoelectric focusing; the codifying gene of this betalactamase was identified by hybridisation with a TEM-1 probe labeled with digoxigenine. Strains studied were 110, obtained during the period 1987 to 1989 and isolated from four Hospitals of the Vallés area of Barcelona.

RESULTS

Enzyme production was detected in 105 of 110 strains studied; TEM-1 type betalactamase was identified in 108 and positive hybridisation was obtained in these strains with the TEM-1 probe.

CONCLUSIONS

Nitrocefin hydrolysis is a reliable test for the detection of betalactamase production, although it may be unable to detect it (falses negatives) when the production is low. The only betalactamase type identified was TEM-1. The frequency of the strains with non-enzymatic resistance was 1.8%.

Neisseria meningitidis with reduced sensitivity to penicillin: observations in 10 children

10/84 strains (11.9%) of Neisseria meningitidis isolated from blood and/or cerebrospinal fluid in children 1986-1987 had reduced sensitivity to benzylpenicillin (MICs 0.1-0.4 mg/l). Group C meningococci predominated among these strains. The clinical course was satisfactory in all cases regardless of the antibiotic treatment used, although the time to abatement of fever was prolonged compared to that of children infected with susceptible strains.

[Type TEM beta-lactamase activity in a Neisseria meningitidis strain]

We studied the beta-lactamase activity characteristics of a penicillin G resistant N. meningitidis strain (MIC = 8 micrograms/ml) isolated from a septicemic process, in an eleven month old girl, attended in the Sabadell Hospital (Barcelona). The beta-lactamase substrate profile was broad-spectrum (it hydrolyses penicillin G and cephaloridine) and the nitrocefin hydrolysis was inhibited by clavulanic acid. The analytical isoelectric focusing of the enzyme showed that the isoelectric point of the main band and, the secondary bands, were compatible with those of the type TEM-1 standard enzyme. We also obtained a positive DNA-DNA hybridization with the TEM-1 beta-lactamase (pBR322 plasmid).

Isolation of Neisseria meningitidis strains with increase of penicillin minimal inhibitory concentrations

We report the isolation and characterization of ten strains showing an increase in the minimal inhibitory concentrations to penicillin (MICs greater than 0.1 microgram/ml), and describe the epidemiological, clinical and microbiological features. The susceptibility of 3432 meningococcal strains isolated from patients in the recent epidemic wave (1978-86) in Spain, to several antimicrobial agents used in the treatment and chemoprophylaxis of meningococcal infection has been tested. Most were resistant to sulphadiazine but sensitive to other antibiotics. The possible existence of a new pattern of behaviour of meningococcal to penicillin is discussed.

Neisseria meningitidis strains with decreased susceptibility to penicillin

Neisseria meningitidis strains relatively resistant to penicillin were recovered from blood or cerebrospinal fluid cultures of four children treated in Barcelona, Spain, and surrounding areas. The four strains had distinct serogrouping and serotyping patterns. The minimal inhibitory concentrations of penicillin were 0.25 microgram/ml for three strains and 0.5 microgram/ml for the fourth strain. These are the first relatively penicillin-resistant meningococcal strains identified in Spain.