Two multi-fragment recombination events resulted in the β-lactam-resistant serotype 11A-ST6521 related to Spain9V-ST156 pneumococcal clone spreading in south-western Europe, 2008 to 2016

BackgroundThe successful pneumococcal clone Spain9V-ST156 (PMEN3) is usually associated with vaccine serotypes 9V and 14.AimOur objective was to analyse the increase of a serotype 11A variant of PMEN3 as cause of invasive pneumococcal disease (IPD) in Spain and its spread in south-western Europe.MethodsWe conducted a prospective multicentre study of adult IPD in Spain (2008-16). Furthermore, a subset of 61 penicillin-resistant serotype 11A isolates from France, Italy, Portugal and Spain were subjected to whole genome sequencing (WGS) and compared with 238 genomes from the European Nucleotide Archive (ENA).ResultsAlthough the incidence of serotype 11A in IPD was stable, a clonal shift was detected from CC62 (penicillin-susceptible) to CC156 (penicillin-resistant). By WGS, three major 11A-CC156 lineages were identified, linked to ST156 (n = 5 isolates; France, Italy and Portugal), ST166 (n = 4 isolates; France and Portugal) and ST838/6521 (n = 52 isolates; France, Portugal and Spain). Acquisition of the 11A capsule allowed to escape vaccine effect. AP200 (11A-ST62) was the donor for ST156 and ST838/6521 but not for ST166. In-depth analysis of ST838/6521 lineage showed two multi-fragment recombination events including four and seven fragments from an 11A-ST62 and an NT-ST344 representative, respectively.ConclusionThe increase in penicillin-resistant serotype 11A IPD in Spain was linked to the spread of a vaccine escape PMEN3 recombinant clone. Several recombination events were observed in PMEN3 acquiring an 11A capsule. The most successful 11A-PMEN3 lineage spreading in south-western Europe appeared after two multi-fragment recombination events with representatives of two major pneumococcal clones (11A-ST62 and NT-ST344).

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.

Trends in the incidence and mortality of patients with community-acquired septic shock 2003-2016

PURPOSE

To evaluate the incidence and mortality of adult patients with community-acquired septic shock (CASS) and the influence of source control (SC) and other risk factors on the outcome.

MATERIAL AND METHODS

The study included patients with CASS admitted to the ICU at a university hospital (2003-2016). Multivariate analyses were performed to identify risk factors of ICU mortality.

RESULTS

A total of 625 patients were included. The incidence showed an average annual increase of 4.9% and the mortality an average annual decrease of 1.4%. The patients who required SC showed a lower mortality (20.4%) than patients who did not require SC (31.3%) (p = 0.002). However, the evolution in mortality was different: Mortality decreased in patients who did not require SC (from 56.3% to 20%; p = 0.02), but did not differ in those who required SC (from 21.4% to 27.6%; p = 0.43). In the multivariate analysis, severity at admission, age, alcoholism, cirrhosis, ARDS, neutropenia and thrombocytopenia were associated with worse outcome, whereas appropriate antibiotic treatment and adequate SC were independently associated with better survival.

CONCLUSIONS

The incidence of CASS increased and the ICU mortality decreased during the study period. The mortality was mainly due to a decrease in mortality in infections not requiring SC.

Chorioamnionitis due to Leptotrichia trevisanii

Very long fusiform gram-negative bacilli were observed after Gram staining of amniotic fluid from a 36-year-old multigravida woman. At 24 hours, pure, abundant growth of smooth, gray, only slightly convex catalase-positive and oxidase-negative colonies measuring about 2 mm were observed. Growth was greater in anaerobic than in aerobic conditions. The bacterium was identified as Leptotrichia trevisanii by matrix-assisted laser desorption ionization time of flight mass spectrometry. Ampicillin and gentamicin were prescribed for chorioamnionitis, and vaginal prostaglandins were administered to terminate the pregnancy. The patient remained afebrile throughout 48 hours and was discharged. Microscopic examination of the placenta revealed severe acute chorioamnionitis with a maternal inflammatory response and abundant bacillary-shaped microorganisms. To our knowledge, this isolate constitutes the first reported case of chorioamnionitis caused by L. trevisanii.

Phylogeny, resistome and mobile genetic elements of emergent OXA-48 and OXA-245 Klebsiella pneumoniae clones circulating in Spain

OBJECTIVES

The global emergence of OXA-48-producing Klebsiella pneumoniae clones is a significant threat to public health. We used WGS and phylogenetic analysis of Spanish isolates to investigate the population structure of blaOXA-48-like-expressing K. pneumoniae ST11 and ST405 and to determine the distribution of resistance genes and plasmids encoding blaOXA-48-like carbapenemases.

METHODS

SNPs identified in whole-genome sequences were used to reconstruct phylogenetic trees, identify resistance determinants and de novo assemble the genomes of 105 blaOXA-48-like-expressing K. pneumoniae isolates.

RESULTS

Genome variation was generally lower in outbreak-associated isolates compared with those associated with sporadic infections. The relatively limited variation observed within the outbreak-associated isolates was on average 7-10 SNPs per outbreak. Of 24 isolates from suspected sporadic infections, 7 were very closely related to isolates causing hospital outbreaks and 17 were more diverse and therefore probably true sporadic cases. On average, 14 resistance genes were identified per isolate. The 17 ST405 isolates from sporadic cases of infection had four distinct resistance gene profiles, while the resistance gene profile differed in all ST11 isolates from sporadic cases. Sequence analysis of 94 IncL/M plasmids carrying blaOXA-48-like genes revealed an average of two SNP differences, indicating a conserved plasmid clade.

CONCLUSIONS

Whole-genome sequence analysis enabled the discrimination of outbreak and sporadic isolates. Significant inter-regional spread within Spain of highly related isolates was evident for both ST11 and ST405 K. pneumoniae. IncL/M plasmids carrying blaOXA-48-like carbapenemase genes were highly conserved geographically and across the outbreaks, sporadic cases and clones.

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.

Effects of immunocompromise and comorbidities on pneumococcal serotypes causing invasive respiratory infection in adults: implications for vaccine strategies

BACKGROUND

The 13-valent pneumococcal conjugate vaccine (PCV13) has recently been approved for use in immunocompromised adults. However, it is unclear whether there is an association between specific underlying conditions and infection by individual serotypes. The objective was to determine the prevalence of serotypes covered by PCV13 in a cohort of patients with invasive pneumococcal disease of respiratory origin and to determine whether there are specific risk factors for each serotype.

METHODS

An observational study of adults hospitalized with invasive pneumococcal disease in 2 Spanish hospitals was conducted during the period 1996-2011. A multinomial regression analysis was performed to identify conditions associated with infection by specific serotypes (grouped according their formulation in vaccines and individually).

RESULTS

A total of 1094 patients were enrolled; the infecting serotype was determined in 993. In immunocompromised patients, 64% of infecting serotypes were covered by PCV13. After adjusting for age, smoking, alcohol abuse, and nonimmunocompromising comorbidities, the group of serotypes not included in either PCV13 or PPV23 were more frequently isolated in patients with immunocompromising conditions and cardiopulmonary comorbidities. Regarding individual serotypes, 6A, 23F, 11A, and 33F were isolated more frequently in patients with immunocompromise and specifically in some of their subgroups. The subgroup analysis showed that serotype10A was also associated with HIV infection.

CONCLUSIONS

Specific factors related to immunocompromise seem to determine the appearance of invasive infection by specific pneumococcal serotypes. Although the coverage of serotypes in the 13-valent conjugate pneumococcal vaccine (PCV13) was high, some non-PCV13-emergent serotypes are more prevalent in immunocompromised patients.

Emergence of OXA-48-producing Klebsiella pneumoniae and the novel carbapenemases OXA-244 and OXA-245 in Spain

OBJECTIVES

To describe the molecular and population-level characterization of a selected group of OXA-48-like-producing Klebsiella pneumoniae isolates collected in Spain between January 2011 and May 2012.

METHODS

During the study period, 151 OXA-48-like-producing K. pneumoniae isolates were collected from 10 hospitals in six different Spanish regions. From these, a representative sample of 21 isolates that caused hospital outbreaks and single infections was selected for further in-depth analysis. Molecular epidemiology was investigated using PFGE and multilocus sequence typing (MLST). Resistance genes were characterized by PCR and sequencing. Plasmids carrying bla(OXA-48-like) were studied by PFGE with S1 nuclease digestion.

RESULTS

All 21 isolates had ertapenem MICs ≥ 1 mg/L, but 47.6% remained susceptible to imipenem and meropenem; bla(OXA-48) was identified in 19 isolates (90.5%) and the novel bla(OXA-244) and bla(OXA-245) genes were detected in 1 isolate each. With one exception, all isolates that contained bla(OXA-48-like) also contained bla(CTX-M-15). PFGE typing revealed six clusters comprising isolates that belonged to MLST types ST11, ST16, ST392, ST405, ST437 and ST663, respectively. Two main clusters were identified: PFGE cluster 1 (12 isolates, belonging either to ST405 or ST663, from seven hospitals), and PFGE cluster 2 (4 ST16 isolates from two hospitals). Six of seven donor isolates conjugated successfully; bla(OXA-48-like) (but not bla(CTX-M-15)) was carried on ≈ 60 kb Inc L/M plasmids.

CONCLUSIONS

Multidrug-resistant K. pneumoniae producing OXA-48-like carbapenemase are emerging as important pathogens in Spain due to intra- and inter-hospital, clonal and non-clonal dissemination.

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.

Why mortality is increased in health-care-associated pneumonia: lessons from pneumococcal bacteremic pneumonia

BACKGROUND

A cohort of patients with bacteremic Streptococcus pneumoniae pneumonia was reviewed to assess why mortality is higher in health-care-associated pneumonia (HCAP) than in community-acquired pneumonia (CAP).

METHODS

A prospective cohort of all adult patients with bacteremic pneumococcal pneumonia attended at the ED was used.

RESULTS

One hundred eighty-four cases were classified as CAP and 44 (19%) as HCAP. Fifty-two (23%) were admitted to the ICU. Three (1.5%) isolates were resistant to beta-lactams, and only two patients received inappropriate therapy. The CAP cohort was significantly younger (median age 68 years, interquartile range [IQR] 42-78 vs 77 years, IQR 67-82, P < .001). The HCAP cohort presented a higher Charlson index (2.81 +/- 1.9 vs 1.23 +/- 1.42, P < .001) and had higher severity of illness at admission (altered mental status, respiratory rate > 30/min, Pao(2)/Fio(2) < 250, and multilobar involvement). HCAP patients had a lower rate of ICU admission (11.3% vs 25.5%, P < .05), and a trend toward lower mechanical ventilation (9% vs 19%, P = .17) and vasopressor use (9% vs 18.4%, P = .17) were documented. More patients in the HCAP cohort presented with a pneumonia severity index score > 90 (class IV-V, 95% vs 65%, P < .001), and 30-day mortality was significantly higher (29.5% vs 7.6%, P < .001). A multivariable regression logistic analysis adjusting for underlying conditions and variables related to severity of illness confirmed that HCAP is an independent variable associated with increased mortality (odds ratio = 5.56; 95% CI, 1.86-16.5).

CONCLUSIONS

Pneumococcal HCAP presents excess mortality, which is independent of bacterial susceptibility. Differences in outcomes were probably due to differences in age, comorbidities, and criteria for ICU admission rather than to therapeutic decisions.

Candidemia in neonatal intensive care units: Barcelona, Spain

BACKGROUND

Candida spp. are increasingly important hospital-acquired pathogens in neonatal intensive care units (NICU) and cause considerable mortality in preterm infants. Most studies have been limited to a single institution. The aim of this study was to determine the epidemiology of candidemia in all Barcelona NICUs.

METHODS

We conducted prospective population-based surveillance for candidemia in Barcelona, Spain, during 2002-2003. This report focuses on the results from 5 participating hospitals with NICUs.

RESULTS

We detected 24 cases, resulting in an annual incidence of 32.6 cases per 100,000 live births and 1.1 cases per 100 NICU discharges. Median gestational age was 27.5 weeks (range, 24-40.5), and there were 21 cases among very low birth weight infants. Among the 20 (83%) cases evaluated for the presence of end organ infection, endophthalmitis occurred in 2 cases, and endocarditis, meningitis and peritonitis occurred in 1 case each. Candida parapsilosis was the most frequent species isolated (67%). All isolates were fluconazole-susceptible. Crude mortality was 21%.

CONCLUSIONS

The preponderance of C. parapsilosis candidemias observed in Barcelona NICUs is similar to reports from the literature. Morbidity and mortality associated with neonatal candidemia remain high.

Prospective observational study of bacteremic pneumococcal pneumonia: Effect of discordant therapy on mortality*

STUDY OBJECTIVE

To evaluate the effect of discordant empirical therapy on outcome in bacteremic pneumococcal community-acquired pneumonia.

DESIGN

Prospective observational study.

SETTING

A 600-bed teaching hospital with a reference area of 400,000 inhabitants.

PATIENTS

All patients aged > or =18 yrs with a diagnosis of community-acquired pneumonia whose blood cultures, obtained within the first 48 hrs of hospitalization, demonstrated growth of Streptococcus pneumoniae were included in the study.

METHODS

Discordant therapy was defined as failure to administer an antibiotic with in vitro activity against the isolated strain within 24 hrs of hospital admission. The 2002 breakpoints recommended for respiratory infections by the National Committee for Clinical Laboratory Standards were used to classify therapy.

RESULTS

A total of 100 patients with bacteremic pneumococcal pneumonia were identified. Penicillin- and macrolide-resistant strains were identified in 29 and 18 cases, respectively. Only two strains had minimum inhibitory concentrations of >2 microg/mL for cephalosporins. Discordant therapy was documented in ten patients, five of whom died. Mortality in patients receiving concordant therapy was 14% (13 of 90). Nursing home residence (odds ratio [OR] = 14.8) and immunocompromise (OR = 11.5) were independently (p <.05) associated with discordant therapy. Risk of discordant therapy was significantly higher (p <.05) when empirical therapy did not include cefotaxime or ceftriaxone (OR = 10.4). Discordant therapy (OR = 27.3), multilobar involvement (OR = 14.2), underlying chronic obstructive pulmonary disease (OR = 9.1), and hospitalization during the previous 12 wks (OR = 7.9) were independently associated (p <.05) with death. The excess mortality for initial discordant therapy was estimated to be 35.6% (95% confidence interval, 3.73-67.4).

CONCLUSIONS

Survival in patients with bacteremic community-acquired pneumococcal pneumonia can be improved by avoiding suboptimal therapy. Using the 2002 breakpoints, it is very unlikely that discordant therapy would be given with ceftriaxone or cefotaxime. Clinical outcome is worse in those patients receiving antimicrobial therapy that in vitro testing suggests would be ineffective.

[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.

Evaluation of the BacT/Alert and VITAL blood culture systems for the diagnosis of bacteremia

OBJECTIVE: To evaluate the detection of bacterial growth in the BacT/Alert (Organon Teknika) and VITAL (bioMérieux) automated blood culture systems. METHODS: In accordance with the protocol of study, 1021 blood sample pairs for culture were obtained from adult patients admitted to the Emergency Room and Intensive Care Unit. RESULTS: In total, 139 (13.6%) clinically significant blood cultures were detected, of which 79 (56.8%) were detected by both systems, 48 (34.5%) only by BacT/Alert and 12 (8.6%) only by VITAL (P cent0.0001). The BacT/Alert system detected positive blood cultures more rapidly for all groups of microorganisms. The VITAL system showed six false-negative blood cultures, while the BacT/Alert system showed none (P50.03). There was no significant difference between the number of false-positive blood cultures detected by the two systems. CONCLUSIONS: In our study, overall the BacT/Alert system achieved a better recovery of microorganisms than the VITAL system.

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.

Endemic meningococcal disease in Cerdanyola, Spain, 1987--93: molecular epidemiology of the isolates of Neisseria meningitidis

OBJECTIVE: To establish the relationships between 30 Neisseria meningitidis strains isolated in Cerdanyola (Spain) from 30 out of 36 sporadic cases of meningococcal disease (MD) during 1987--93 and their spread in this population by multilocus enzyme electrophoresis (MEE) and by pulsed-field gel electrophoresis (PFGE), and to evaluate the usefulness of PFGE versus serologic typing methods and MEE as an alternative epidemiologic marker to study meningococcal infection. METHODS: Serotyping, electrophoretic mobility of seven isoenzymes determined by MEE and chromosomal DNA macrorestriction with NheI resolved by PFGE were analyzed. RESULTS: Of these 30 strains, 25 were serogroup B and the remaining five were serogroup C, with the 4:P1.15 and the 2b:NT as the most common antigenic phenotypes, respectively. There were 13 electrophoretic types (ETs) by MEE, with 14 isolates showing an identical ET, 8. Sixteen pulse types (PTs) were generated by PFGE. The 14 ET 8 isolates were clustered into six PTs, A1, A2, A4, A5, A6 and A8. However, by combining both methods, 19 genetically distinct groups were obtained. Eleven of these groups (20 serogroup B strains) and two of these (four serogroup C strains) were genetically related. CONCLUSIONS: We conclude that, according to the clonal population structure, these 30 N. meningitidis strains are heterogeneous although a great number are related. Moreover, PFGE is a useful method to establish clonal structure in N. meningitidis strains under endemic conditions. Finer discrimination of these strains was achieved by combining both MEE and PFGE methods.

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.