In vitro activity of imipenem/relebactam against Pseudomonas aeruginosa isolates recovered from ICU patients in Spain and Portugal (SUPERIOR and STEP studies)

OBJECTIVES

To study the in vitro activity of imipenem/relebactam and comparators and the imipenem/relebactam resistance mechanisms in a Pseudomonas aeruginosa collection from Portugal (STEP, 2017-18) and Spain (SUPERIOR, 2016-17) surveillance studies.

METHODS

P. aeruginosa isolates (n = 474) were prospectively recovered from complicated urinary tract (cUTI), complicated intra-abdominal (cIAI) and lower respiratory tract (LRTI) infections in 11 Portuguese and 8 Spanish ICUs. MICs were determined (ISO broth microdilution). All imipenem/relebactam-resistant P. aeruginosa isolates (n = 30) and a subset of imipenem/relebactam-susceptible strains (n = 32) were characterized by WGS.

RESULTS

Imipenem/relebactam (93.7% susceptible), ceftazidime/avibactam (93.5% susceptible) and ceftolozane/tazobactam (93.2% susceptible) displayed comparable activity. The imipenem/relebactam resistance rate was 6.3% (Portugal 5.8%; Spain 8.9%). Relebactam restored imipenem susceptibility to 76.9% (103/134) of imipenem-resistant isolates, including MDR (82.1%; 32/39), XDR (68.8%; 53/77) and difficult-to-treat (DTR) isolates (67.2%; 45/67). Among sequenced strains, differences in population structure were detected depending on the country: clonal complex (CC)175 and CC309 in Spain and CC235, CC244, CC348 and CC253 in Portugal. Different carbapenemase gene distributions were also found: VIM-20 (n = 3), VIM-1 (n = 2), VIM-2 (n = 1) and VIM-36 (n = 1) in Spain and GES-13 (n = 13), VIM-2 (n = 3) and KPC-3 (n = 2) in Portugal. GES-13-CC235 (n = 13) and VIM type-CC175 (n = 5) associations were predominant in Portugal and Spain, respectively. Imipenem/relebactam showed activity against KPC-3 strains (2/2), but was inactive against all GES-13 producers and most of the VIM producers (8/10). Mutations in genes affecting porin inactivation, efflux pump overexpression and LPS modification might also be involved in imipenem/relebactam resistance.

CONCLUSIONS

Microbiological results reinforce imipenem/relebactam as a potential option to treat cUTI, cIAI and LRTI caused by MDR/XDR P. aeruginosa isolates, except for GES-13 and VIM producers.

Diagnostic value of quantitative SPECT/CT in assessing active sacroiliitis in patients with axial spondylarthritis and/or inflammatory low back pain

BACKGROUND

The diagnostic accuracy of bone scintigraphy (BS) increases with SPECT/CT imaging. It would therefore be appropriate to reassess the diagnostic utility of scintigraphy in sacroiliitis with axial spondyloarthritis (SpA). The aim of this study was to compare the diagnostic performance of MRI, SPECT/CT and a combination of both techniques in sacro-iliitis, and to evaluate the correlation between quantitative SPECT/CT indices and quantitative MRI inflammatory lesion scores.

METHODS

Thirty-one patients with active SpA and 22 patients with inflammatory low back pain underwent MRI and SPECT/CT of the sacroiliac joints. The diagnostic accuracy of both techniques was calculated using clinical diagnosis as the gold standard. The correlation between MRI and SPECT/CT was calculated by comparing the SPECT/CT activity indices and the Berlin/SPARCC scoring systems for MRI.

RESULTS

The sensitivity and specificity values in quantitative SPECT/CT, taking the sacroiliac/promontory ratio of >1.36 as the cut-off value, were close to those from MRI published in the literature. The combination of both techniques increased sensitivity while maintaining high specificity. There was a moderate correlation between SPECT/CT and MRI total scores. This correlation was improved by using solely the MRI inflammation scores.

CONCLUSION

Quantitative SPECT/CT showed better diagnostic accuracy than planar scintigraphy and showed a moderate correlation with MRI scores in active sacroiliitis. The combination of both tests increased the diagnostic accuracy. Quanti-tative SPECT/CT could play a relevant role in the diagnosis of active sacroiliitis in patients with high a suspicion of SpA and a negative/inconclusive MRI test or in patients with whom MRI studies cannot be carried out.

Diagnostic accuracy of visual analysis versus dual time-point imaging with 18F-FDG PET/CT for the characterization of indeterminate pulmonary nodules with low uptake

OBJECTIVE

To determine the accuracy of visual analysis and the retention index (RI) with dual-time point ¹⁸F-FDG PET/CT for the characterization of indeterminate pulmonary nodules (IPN) with low FDG uptake.

MATERIALS AND METHODS

A retrospective analysis was performed on 43 patients (28 men, 64 ± 11 years old, range 36-83 years) referred for IPN characterization with ¹⁸F-FDG-PET/CT and maximum standard uptake value ≤ 2.5 at 60 minutes post-injection (SUV_max1). Nodules were analyzed by size, visual score for FDG uptake on standard (OSEM 2,8) and high definition (HD) reconstructions, SUV_max1, SUV_max at 180 minutes post-injection (SUV_max2), and RI was calculated. The definitive diagnosis was based on histopathological confirmation (n = 28) or ≥ 2 years of follow-up.

RESULTS

Twenty-four (56%) nodules were malignant. RI ≥ 10% on standard reconstruction detected 18 nodules that would have been considered negative using the standard SUV_max ≥ 2.5 criterion for malignancy. RI ≥ 10% had a sensitivity, specificity, PPV, NPV and accuracy of 75, 73.7, 78.3, 70, and 74.4%, respectively, while for FDG uptake > liver on HD these were 79.1, 63.2, 73.1, 70.6, and 72.1%, respectively. SUV_max1 ≥ 2, SUV_max2 > 2.5 and FDG uptake > liver on standard reconstruction had a PPV of 100%. FDG uptake > mediastinum on HD had a NPV of 100%.

CONCLUSIONS

RI ≥ 10% was the most accurate criterion for malignancy, followed by FDG uptake > liver on HD reconstruction. On standard reconstruction, SUV_max1 ≥2 was highly predictive of malignancy, as well as SUV_max2 > 2.5 and FDG uptake > liver. FDG uptake < mediastinum on HD was highly predictive of benign nodules.

Distinct epidemiology and resistance mechanisms affecting ceftolozane/tazobactam in Pseudomonas aeruginosa isolates recovered from ICU patients in Spain and Portugal depicted by WGS

Objectives

To analyse the epidemiology, the resistome and the virulome of ceftolozane/tazobactam-susceptible or -resistant Pseudomonas aeruginosa clinical isolates recovered from surveillance studies in Portugal (STEP, 2017–18) and Spain (SUPERIOR, 2016–17).

Methods

P. aeruginosa isolates were recovered from intra-abdominal, urinary tract and lower respiratory tract infections in ICU patients admitted to 11 Portuguese and 8 Spanish hospitals. MICs were determined (ISO-standard broth microdilution, EUCAST 2020 breakpoints). A subset of 28 ceftolozane/tazobactam-resistant P. aeruginosa isolates were analysed and compared with 28 ceftolozane/tazobactam-susceptible P. aeruginosa strains by WGS.

Results

Clonal complex (CC) 235 (27%) and CC175 (18%) were the most frequent, followed by CC244 (13%), CC348 (9%), CC253 (5%) and CC309 (5%). Inter-hospital clonal dissemination was observed, limited to a geographical region (CC235, CC244, CC348 and CC253 in Portugal and CC175 and CC309 in Spain). Carbapenemases were detected in 25 isolates (45%): GES-13 (13/25); VIM type (10/25) [VIM-2 (4/10), VIM-20 (3/10), VIM-1 (2/10) and VIM-36 (1/10)]; and KPC-3 (2/25). GES-13-CC235 (13/15) and VIM type-CC175 (5/10) associations were observed. Interestingly, KPC-3 and VIM-36 producers showed ceftolozane/tazobactam-susceptible phenotypes. However, ceftolozane/tazobactam resistance was significantly associated with GES-13 and VIM-type carbapenemase production. Six non-carbapenemase producers also displayed ceftolozane/tazobactam resistance, three of them showing known ceftolozane/tazobactam resistance-associated mutations in the PBP3 gene, ftsI (R504C and F533L). Overall, an extensive virulome was identified in all P. aeruginosa isolates, particularly in carbapenemase-producing strains.

Conclusions

GES-13-CC235 and VIM type-CC175 were the most frequent MDR/XDR P. aeruginosa clones causing infections in Portuguese and Spanish ICU patients, respectively. Ceftolozane/tazobactam resistance was mainly due to carbapenemase production, although mutations in PBP-encoding genes may additionally be involved.

Genetic Background and Expression of the New qepA4 Gene Variant Recovered in Clinical TEM-1- and CMY-2-Producing Escherichia coli

A new QepA4 variant was detected in an O86:H28 ST156-fimH38 Escherichia coli, showing a multidrug-resistance phenotype. PAβN inhibition of qepA4-harboring transconjugant resulted in increase of nalidixic acid accumulation. The qepA4 and catA1 genes were clustered in a 26.0-kp contig matching an IncF-type plasmid, and containing a Tn21-type transposon with multiple mobile genetic elements. This QepA variant is worrisome because these determinants might facilitate the selection of higher-level resistance mutants, playing a role in the development of resistance, and/or confer higher-level resistance to fluoroquinolones in association with chromosomal mutations.

Determinants of the Sympatric Host-Pathogen Relationship in Tuberculosis

Major contributions from pathogen genome analysis and host genetics have equated the possibility of Mycobacterium tuberculosis co-evolution with its human host leading to more stable sympatric host–pathogen relationships. However, the attribution to either sympatric or allopatric categories depends on the resolution or grain of genotypic characterization. We explored the influence on the sympatric host-pathogen relationship of clinical (HIV infection and multidrug-resistant tuberculosis [MDRTB]) and demographic (gender and age) factors in regards to the genotypic grain by using spacer oligonucleotide typing (spoligotyping) for classification of M. tuberculosis strains within the Euro-American lineage. We analyzed a total of 547 tuberculosis (TB) cases, from six year consecutive sampling in a setting with high TB-HIV coinfection (32.0%). Of these, 62.0% were caused by major circulating pathogen genotypes. The sympatric relationship was defined according to spoligotype in comparison to the international spoligotype database SpolDB4. While no significant association with Euro-American lineage was observed with any of the factors analyzed, increasing the resolution with spoligotyping evidenced a significant association of MDRTB with sympatric strains, regardless of the HIV status. Furthermore, distribution curves of the prevalence of sympatric and allopatric TB in relation to patients’ age showed an accentuation of the relevance of the age of onset in the allopatric relationship, as reflected in the trimodal distribution. On the contrary, sympatric TB was characterized by the tendency towards a typical (standard) distribution curve. Our results suggest that within the Euro-American lineage a greater degree of genotyping fine-tuning is necessary in modeling the biological processes behind the host-pathogen interplay. Furthermore, prevalence distribution of sympatric TB to age was suggestive of host genetic determinisms driven by more common variants.

Analysis of the stability of high-solids anaerobic digestion of agro-industrial waste and sewage sludge

The pilot-scale high-solids anaerobic digestion (HS-AD) of agro-industrial wastes and sewage sludge was analysed in terms of stability by monitoring the most common parameters used to check the performance of anaerobic digesters, i.e. Volatile Fatty Acids (VFA), ammonia nitrogen, pH, alkalinity and methane production. The results reflected similar evolution for the parameters analysed, except for an experiment that presented an unsuccessful start-up. The rest of the experiments ran successfully, although the threshold values proposed in the literature for the detection of an imbalance in wet processes were exceeded, proving the versatility of HS-AD to treat different wastes. The results evidence the need for understanding the dynamics of a high-solids system so as to detect periods of imbalance and to determine inhibitory levels for different compounds formed during anaerobic decomposition. Moreover, the findings presented here could be useful in developing an experimental basis to construct new control strategies for HS-AD.

Tuberculosis diagnosis after bleach processing for early stage tuberculosis laboratory capacity building

The diagnosis of tuberculosis is seriously hampered in the absence of standard biosafety laboratory facilities for specimen concentration and Mycobacterium tuberculosis culture. Within a laboratory twinning arrangement, heat-fixed direct smear and sediment from 74 bleach-processed and 20 non-processed specimens from Cumura Hospital, Guinea-Bissau, were sent to Lisbon for molecular evaluation of rifampicin resistance. Sequence analysis of a 369 base-pair rpoB locus detected 3.2% (3/94) resistant specimens. To our knowledge, this represents the first report on the molecular analysis of M. tuberculosis from bleach-processed sputum, an alternative to current diagnostic practice in low-resource settings.

Water network cost optimization in a paper mill based on a new library of mathematical models

The increasing costs associated with water supply and the disposal of wastewater has stimulated industries to seek more efficient water management systems. Mathematical modelling and simulation can be a very valuable tool for the study of the multiple alternatives available whilst assessing optimum solutions for water management in industry. This study introduces a new steady state model library able to reproduce industrial water circuits. It has been implemented in a novel software framework for the representation, simulation and optimization of industrial water networks. A water circuit representing a paper mill has been modelled and simulated showing the capability to reproduce real case studies. Alternative scenarios for the water network have also been tested to assess the capability of the models to optimize water circuits minimizing total cost.

A knowledge-based control system for air-scour optimisation in membrane bioreactors

Although membrane bioreactors (MBRs) technology is still a growing sector, its progressive implementation all over the world, together with great technical achievements, has allowed it to reach a mature degree, just comparable to other more conventional wastewater treatment technologies. With current energy requirements around 0.6-1.1 kWh/m3 of treated wastewater and investment costs similar to conventional treatment plants, main market niche for MBRs can be areas with very high restrictive discharge limits, where treatment plants have to be compact or where water reuse is necessary. Operational costs are higher than for conventional treatments; consequently there is still a need and possibilities for energy saving and optimisation. This paper presents the development of a knowledge-based decision support system (DSS) for the integrated operation and remote control of the biological and physical (filtration and backwashing or relaxation) processes in MBRs. The core of the DSS is a knowledge-based control module for air-scour consumption automation and energy consumption minimisation.

High prevalence of ST121 in community-associated methicillin-susceptible Staphylococcus aureus lineages responsible for skin and soft tissue infections in Portuguese children

In order to evaluate the incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in Portugal, we analyzed a collection of 38 S. aureus isolates recovered from 30 children attending the pediatric emergency department of a central hospital in Lisbon due to skin and soft tissue infections. Molecular characterization identified seven clonal lineages among the 35 methicillin-susceptible S. aureus (MSSA) isolates, of which the major lineage PFGE A/t159/ST121 included 63% of the isolates. The three MRSA isolates belonged to the Pediatric clone PFGE D/t535/ST5-IV (n = 2) and to the European CA-MRSA clone PFGE G/t044/ST80-IVc (n = 1). All isolates harbored several virulence factors, namely, leukocidins. Panton-Valentine leukocidin (PVL) was produced by isolates from five MSSA lineages and by the ST80 MRSA. Of interest, this is the first reported isolation of CA-MRSA ST80 in Portugal.

Knowledge-based system for automatic MBR control

MBR technology is currently challenging traditional wastewater treatment systems and is increasingly selected for WWTP upgrading. MBR systems typically are constructed on a smaller footprint, and provide superior treated water quality. However, the main drawback of MBR technology is that the permeability of membranes declines during filtration due to membrane fouling, which for a large part causes the high aeration requirements of an MBR to counteract this fouling phenomenon. Due to the complex and still unknown mechanisms of membrane fouling it is neither possible to describe clearly its development by means of a deterministic model, nor to control it with a purely mathematical law. Consequently the majority of MBR applications are controlled in an "open-loop" way i.e. with predefined and fixed air scour and filtration/relaxation or backwashing cycles, and scheduled inline or offline chemical cleaning as a preventive measure, without taking into account the real needs of membrane cleaning based on its filtration performance. However, existing theoretical and empirical knowledge about potential cause-effect relations between a number of factors (influent characteristics, biomass characteristics and operational conditions) and MBR operation can be used to build a knowledge-based decision support system (KB-DSS) for the automatic control of MBRs. This KB-DSS contains a knowledge-based control module, which, based on real time comparison of the current permeability trend with "reference trends", aims at optimizing the operation and energy costs and decreasing fouling rates. In practice the automatic control system proposed regulates the set points of the key operational variables controlled in MBR systems (permeate flux, relaxation and backwash times, backwash flows and times, aeration flow rates, chemical cleaning frequency, waste sludge flow rate and recycle flow rates) and identifies its optimal value. This paper describes the concepts and the 3-level architecture of the knowledge-based DSS and details the knowledge-based control module. Preliminary results of the application of the control module to regulate the air flow rate of an MBR working with variable flux demonstrates the usefulness of this approach.

Responsiveness to stimuli of bispectral index, middle latency auditory evoked potentials and clinical scales in critically ill children

SUMMARY

We performed simultaneous recordings of Bispectral Index (BIS) and middle latency auditory evoked potentials. We also recorded two clinical scales, the Modified Ramsay scale and the COMFORT scale. Heart rate and blood pressure were measured once a day, for a maximum of 5 days, in 81 critically ill children. Changes with tactile, auditory, and painful stimuli were analysed. All the stimuli significantly increased the BIS value, the painful stimulus having the greatest effect. The painful stimulus was the only one that altered the middle latency auditory evoked potentials. Although the responses of the clinical scales to stimuli were statistically significant, they were of little clinical relevance. None of the stimuli used significantly altered the heart rate or blood pressure. We conclude that tactile, auditory and painful stimuli produced changes of little relevance in the clinical scales, BIS or middle latency auditory evoked potentials. We found the BIS was the most sensitive method and the painful stimulus had the greatest effect.

The effect of operational parameters of the process of sludge ozonation on the solubilisation of organic and nitrogenous compounds

An evaluation of various operational parameters on the process of sludge ozonation was carried out based on semi-batch experiments. Particular reference has been given to examine the main parameters affecting the solubilisation of organic matter and nitrogenous compounds. Various sets of experiments were undertaken using real sewage sludge to feed a semi-industrial ozonation plant. Applying ozone dosages between 25 and 35 mg O(3)/gTSS, the organic matter solubilisation obtained through ozonation increases proportionally to ozone dosage until a maximum value of 430 mg COD/L. Concerning the nitrogenous compounds, no variation in nitrite concentration and a low increase in nitrate concentration were attained, regardless of the applied ozone dosage. Little increase in ammonia concentration was achieved for low ozone dosages, whilst applying dosages higher than 20 mg O(3)/gTSS, the variation of ammonia increased proportionally with ozone dosage. Experiments using hydraulic retention time (HRT) between 10 and 60 min resulted in a similar COD solubilisation, confirming a rapid rate of cell lysis during ozonation of sludge.

Contribution of spoligotyping to the characterization of the population structure of Mycobacterium tuberculosis isolates in Portugal

Tuberculosis is a major health problem in Portugal. To begin characterizing the population structure of Mycobacterium tuberculosis, spoligotyping was used for the systematic typing, through consecutive sampling, of patient isolates from the Amadora-Sintra area of Greater Lisbon. Distribution amongst major spoligotype families, including the Latin American Mediterranean (LAM), T, Haarlem and Beijing, was compared to that of the international spoligotype database SpolDB4 and to the European countries of traditional Portuguese immigration represented in SpolDB4. Spoligotypes from 665 isolates were analyzed and 97 shared international types (SITs) identified. In SpolDB4 Portugal is represented by part of the spoligotypes from this study explaining the reduced number of unidentified patterns. The importance of the LAM family, and especially of LAM1 and LAM9 sub-families that alone represented 38% of all the isolates in this study as compared to 8% relative to the European sub group, led us to believe that at least in this respect the population structure was closer to that of Africa and South America than to Europe. Spoligotypes characteristic of Portugal or Portuguese related settings were identified. These included SIT244 a T1 sub-family predominant in Portugal and Bangladesh, SIT64 a LAM 6 sub-family common to Portugal and Brazil, and SIT1106 a LAM 9 sub-family. These studies were the first in Portugal stressing the importance of monitoring the population structure of M. tuberculosis isolates, an important step towards gaining an understanding of tuberculosis and the dynamics of this disease.

Spoligotyping and pncA polymorphism: a two step scenario for Mycobacterium bovis diagnosis in Portugal

The differential diagnosis of Mycobacterium bovis is important in the control of transmission to the human population and also for treatment since M. bovis is naturally resistant to pyrazinamide. Eleven clinical isolates from the Fernando Fonseca Hospital with Spoligotypes indicative of M. bovis, through the absence of spacers 39-43 but that also counted with the absence of spacer 38, were analyzed. For the identification of these strains, the phenotypic analysis of pyrazinamide resistance and study of the polymorphisms of the pncA and gyrB genes were carried out. The study of the pncA polymorphism revealed that the strains analyzed did not contain the M. bovis specific mutation. In relation the gyrB polymorphisms, using the GenoTypeO MTBC kit, the strains were identified as belonging to the group M. tuberculosis, M. africanum subtipo II e M. canetti. The present investigation enabled us to define new genotypes on which future bacteriological studies should be based. Amongst these the study of the pncA polymorphism was considered important due to the immediate practical implications for the clinician. Evaluating transmission and defining groups of risk is an objective for which support from the veterinary services is considered relevant.

Update on the Spoligotypes of Mycobacterium tuberculosis complex isolates from the Fernando Fonseca Hospital (Amadora-Sintra, Portugal)

The present population study, from 1999 to 2003, has been based on the use of Spoligotyping in the genotyping of 452 isolates of the Mycobacterium tuberculosis complex from tuberculosis patients of the Fernando Fonseca Hospital. Spoligotypes were identified as "shared types" (STs) with the aid of an international database. Eleven rarely found STs, not identified in the database, grouped 8.4% of the isolates. Moreover, particular to Portugal, may be the predominance of STs identified in the database but not previously classified as genotypic families, such as ST244, ST150 and ST389, representing 13.3 % of the total. The identification of clinical isolates of M. africanum genotype Afri1 and of M. tuberculosis genotype CAS1 may confirm import of isolates of African and Asian origin. M. tuberculosis of the Beijing family was first reported by us as of 1999. Since then, the number of isolates at the Hospital has passed from one to five annually, representing 2.2% of the total and the tenth most predominant family in the present study. M. tuberculosis Beijing may correspond to an emerging problem in Portugal due to recent immigration from Eastern Europe and Asia. Other genotypes, ST150 and ST389, have shown increase, the significance of which is not clear. However, the relative frequencies of the predominant families LAM, T1 and Haarlem remained relatively stable. The present study confirms the genetic variability in Portugal of M. tuberculosis complex isolates. These studies may contribute to the definition of priorities in the national tuberculosis control programs.

Mass and charge conservation check in dynamic models: application to the new ADM1 model

This paper proposes a systematic methodology for the analysis of the mass and charge balances in dynamic models expressed using the Petersen matrix notation. This methodology is based on the definition of the model components via elemental mass fractions and in the estimation of the COD as a function of the redox equations associated with these elements. This approach makes the automatic calculation of all the stoichiometric coefficients under different measuring units and the study of COD, charge or mass fluxes easier. As an example of its application this methodology was applied to the ADM1 in order to illustrate its usefulness for the analysis of organic matter characterisation, nitrogen release or biogas composition in anaerobic digestion. The application of the methodology for a rigorous integration of different IWA models is proposed for further study.

Direct application of the INNO-LiPA Rif.TB line-probe assay for rapid identification of Mycobacterium tuberculosis complex strains and detection of rifampin resistance in 360 smear-positive respiratory specimens from an area of high incidence of multidrug-resistant tuberculosis

The INNO-LiPA Rif.TB assay for the identification of Mycobacterium tuberculosis complex strains and the detection of rifampin (RIF) resistance has been evaluated with 360 smear-positive respiratory specimens from an area of high incidence of multidrug-resistant tuberculosis (MDR-TB). The sensitivity when compared to conventional identification/culture methods was 82.2%, and the specificity was 66.7%; the sensitivity and specificity were 100.0% and 96.9%, respectively, for the detection of RIF resistance. This assay has the potential to provide rapid information that is essential for the effective management of MDR-TB.

Different Proinflammatory Cytokine Serum Pattern in Neonate Patients Undergoing Open Heart Surgery. Relevance of IL-8

The purpose of this work was to investigate the clinical significance of serum levels of proinflammatory cytokines in pediatric patients undergoing cardiopulmonary bypass. We divided the patients in two groups: 8 neonates, and 19 non-newborn children. IL-1beta, IL-6, IL-8, and TNF serum levels were quantified before sternotomy, at admission to the PICU (30 min postoperatively), 24 h after the onset of surgery and 3 days after the operation. Surgical cardiac stress elicits significant increments of IL-6, IL-8 and TNF serum concentrations in both neonates and non-neonates, regardless of their preoperative clinical condition. However, in newborns the magnitude of the proinflammatory cytokine increments was, in particular with IL-8, remarkably greater than in older children. Moreover, neonate and non-neonate patients showed clearly disparate patterns of serum concentrations over time of both IL-8 and TNF. There was a marked relationship between IL-8 levels and postoperative morbidity, evaluated by pulmonary dysfunction, days on inotropic support and days of PICU stay in both neonates and non-neonates patients. In contrast, we found no relationship between serum levels of IL-6 and TNF and postoperative clinical data. Newborn and non-newborn patients undergoing cardiopulmonary bypass exhibit dissimilar patterns of proinflammatory cytokines. IL-8 might be implicated in the multiorganic dysfunction related to cardiopulmonary bypass in pediatric patients.

[Molecular identification using Spoligotyping of strains from the Mycobacterium tuberculosis complex isolated from the Hospital Fernando Fonseca]

Spoligotyping was used in the genotyping of 219 isolates of the Mycobacterium tuberculosis complex, from patients of the Hospital Fernando Fonseca. This technique, based on PCR methodology, analyses a region of the chromosome specific of the Mycobacterium tuberculosis complex, the DR locus (Direct Repeat). With the aid of an international database, we showed that the predominant Spoligotypes belonged to the LAM family (Latino-American Mediterranean), 29.2 %. The LAM 9 family, with 12.3 %, left us attentive to the possible import of the disease through populations from South America, were it has been frequently identified. The genotypic families T1 and Haarlem, with 6.4 % and 8.7 % respectively, represented a frequency typical to Europe. The Beijing family, with 1.4 %, may represent an emerging problem in our country due to recent immigration of Asian and Eastern European populations. Isolates with a Spoligotype of the M. bovis type were found at a high percentage, 3.7 %. In Europe, this infection is extremely rare suggesting the result may not be due to M. bovis infection but to M. bovis BCG (due to vaccination or eventual recombinant BCG based therapies), or M. africanum (due to the proximity of the two species). A high percentage of the Spoligotypes were not identified by the database, 21.4 %. This is the first study of this type amongst us and may be the starting point for the creation of a data base with important consequences on the national program against tuberculosis.

Characteristics of the gluteus medius muscle in an asymptomatic patient with radiographic signs of coxarthrosis

This case study describes the micromorphology and some biochemical features of gluteus medius muscle in a 79-year-old woman with radiographic signs of coxarthrosis but with no clinical symptoms who initially was admitted in the orthopaedic emergency service with a non-displaced subcapital fracture of the femoral neck due to a domestic accident (fall). The X-ray of the hip showed some characteristic features of coxarthrosis, classified grade 2 of the Kellgren criteria. After informed consent, it was decided to carry out the functional evaluation according to the indexes of Lequesne and WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) and to take a biopsy of the gluteus medius muscle for microscopical examination and myosin heavy chain isoform identification during hip replacement surgery. For the Lequesne Index (score 0-24), the total score was 0, and for the WOMAC (score 0-96), the total score was also 0, both speaking in favour of full joint and muscle function. All the structural features observed in muscle were considered not to have any pathological relevance. The composition of the myosin heavy chains in the gluteus medius muscle was 48% MHC I, 41% MHC IIa, and 11% MHC IIx. The muscle characteristics do not support earlier concepts about muscle weakness as a predisposing factor for osteoarthritis. It is moreover concluded that the diagnosis should rather consider clinical symptoms than radiographic signs of osteoarthritis.

Newborn patients exhibit an unusual pattern of interleukin 10 and interferon gamma serum levels in response to cardiac surgery

OBJECTIVE

The aim of this study was to determine the clinical significance of serum levels of interleukin 10 and interferon gamma in pediatric patients undergoing cardiopulmonary bypass.

METHODS

We divided the patients into 2 groups: 8 neonates and 19 non-newborn children. Interleukin 10 and interferon gamma serum levels were quantified before sternotomy, at admission to the pediatric intensive care unit (30 minutes postoperatively), 24 hours after the onset of the operation, and 3 days after the operation.

RESULTS

Newborn patients displayed significantly greater amounts of serum interleukin 10 than older children, not only in regard to the peak level achieved but also at every postoperative time point analyzed. In contrast, no significant changes in interferon gamma serum levels were observed in neonates at any time point, whereas non-newborn pediatric patients showed a significant increase in interferon gamma serum concentrations immediately after the operation. This unusual pattern of cytokine response in newborn patients was not associated with modifications in cortisol serum levels. Furthermore, although neonates had significantly different surgical and clinical variables than did the non-newborn pediatric patients, the variation in interleukin 10 production in neonates could not be accounted for by differences in the magnitude of surgical injury. In the group of neonates, there were significant positive correlations between peak interleukin 10 serum levels and both partial pressure of arterial oxygen/fraction of inspired oxygen ratio and postoperative body weight gain.

CONCLUSIONS

Newborn patients undergoing cardiopulmonary bypass exhibit a distinctive biologic response pattern characterized by high levels of serum interleukin 10 without changes in serum interferon gamma. This cytokine imbalance could have potential clinical implications.

Relationships between objective physical characteristics and the use of weight control methods in adolescence: a mediating role for eating attitudes?

This study of non-clinical adolescent males and females examined associations of objectively measured physical characteristics with greater use of methods of weight control and considered whether the relationships between these variables might be explained by a mediating effect of a subjective characteristic--unhealthy eating attitudes. Non-clinical male and female adolescents completed measures of weight control and eating attitudes, and their physical characteristics were measured using a range of standardized anthropometry techniques. Regression analyses were used to test the role of eating attitudes as mediators in the relationship between physical characteristics and the use of weight control methods. The data were compatible with a partial mediator model, where physical characteristics influence eating attitudes, and those where attitudes drive the use of methods to control weight. However, not all of the relationship was explained by this mediator. In addition, there were different patterns of association for men and women, consistent with different patterns of bodily focus between the genders. These findings stress the importance of understanding objective physical characteristics as well as subjective eating attitudes to find out why people use different levels of weight control behaviours. Limitations, further research and potential implications for clinical and preventative programmes are discussed.

Hepatic dysfunction after cardiac surgery in children

OBJECTIVE: The objective of this study was to analyze the incidence and significance of hepatic dysfunction after cardiac surgery in children. DESIGN: Prospective, observational study. SETTING: Pediatric intensive care unit of a university hospital. PATIENTS: The study consisted of 232 children ranging in age from newborn to 17 years with no history of liver disease. MEASUREMENTS AND MAIN RESULTS: Aspartate aminotransferase (AST), alanine aminotransferase (ALT), gammaglutamyltranspeptidase (GGT), alkaline phosphatase, total and conjugated bilirubin, blood glucose, urea, creatinine, and coagulation studies were determined at admission, at 24 and 48 hrs, and at 7 days. Hepatic dysfunction was taken as an ALT of > 100 IU/L or a moderate or high hepatic score. The statistical study included bivariate analysis and multivariate logistic regression to study the risk factors for hepatic dysfunction. Twenty-one patients (9%) showed an ALT > 100 IU/L, and 29.3% had a moderate or high hepatic score. A relationship was found between hepatic dysfunction and the type of cardiopathy (D-transposition of the great arteries and coarctation of the aorta), shock, the administration of dopamine or epinephrine, renal insufficiency, the presence of pulmonary changes (pulmonary edema, atelectasis, pulmonary hypertension, hypoxemia), hematologic disturbances (prothrombin time, kaolin-cephalin time, fibrinogen, and platelets), and the need for a greater number of transfusions of packed cells, plasma, and platelets. Compared with 7.6% of the rest of the patients (p <.001), 38% of patients with an ALT > 100 IU/L died. The hepatic score of those patients who died was 4.2 (2.3)-higher than that of the survivors at 1.5 (1.8), (p <.001). Shock and renal insufficiency were the factors most significantly related to the development of hepatic dysfunction. CONCLUSIONS: Hepatic dysfunction is an uncommon complication in children after cardiac surgery. This complication is related mainly to hemodynamic disturbances and renal insufficiency and is an indicator of poor prognosis.

Study of paediatric intensive care units in Spain. Spanish Society of Paediatric Intensive Care

OBJECTIVE

To describe the organisation of paediatric intensive care units in Spain and the medical assistance provided during 1996.

METHODS

A written questionnaire was sent to all the paediatric ICUs linked to or within the Spanish public health system.

RESULTS

Thirty-one of the 34 paediatric ICUs replied. All are medico-surgical units. Eighteen treat only paediatric patients, 12 paediatric and neonatal patients, and one paediatric and adult patients. Fifteen units have fewer than seven beds, eight have between 7 and 12 beds, and eight between 13 and 18 beds. Of the paediatric ICUs, 83.8 % are staffed by paediatricians specialised in paediatric intensive care. The mean number of on-call on site periods of duty for each member of the medical staff was 5.1 +/- 1.7 per month. Thirty of the 31 units undertake paediatric resident training, 13 train residents specialising in paediatric intensive care and 12 participate in medical student training. In 1996 there were 9,585 admissions (309 +/- 182 patients per ICU) signifying 35.3 +/- 14 patients/bed. Of the patients, 65.9 % were medical and 34.1 % surgical. The mean duration of stay was 5.6 +/- 2.1 days. The mortality rate was 5.4 +/- 3.2 %. The main causes of death were multiple organ failure and brain death.

CONCLUSIONS

In Spain, paediatric intensive care is principally performed by specialised paediatricians. Although the general results for 1996 are similar to those of other European countries, efficiency studies are necessary to plan and re-organise the paediatric intensive care units in Spain.

Transpyloric enteral feeding in critically ill children

BACKGROUND

Nutrition is important in childhood because the child has a lower energy reserve than the adult and a higher demand for calories because of ongoing growth. In this study, the utility of transpyloric enteral feeding (TEF) in critically ill children was evaluated.

METHODS

A prospective, descriptive study was made in a pediatric intensive care unit of a tertiary pediatric center of 41 critically ill children, 30 after surgical procedures and 11 with nonsurgical illness, aged 8 days to 12 years, who received transpyloric enteral feeding with 8- or 10-Fr weighted feeding tubes. Analysis was made of tolerance and complications (vomiting, abdominal distension, excessive gastric residual, diarrhea, and pulmonary aspiration) of TEF.

RESULTS

The mean duration of TEF was 19.5 +/- 26.8 days (range, 1-120 days). The administration of sedative agents or inotropic drugs did not alter toleration of TEF. Eight of 12 patients treated with continuous infusion of vecuronium tolerated TEF without complications. Eleven gastrointestinal complications occurred in 10 patients, abdominal distension and excessive gastric residual in 7 (17%), and diarrhea in 4 (9.7%). In 7 patients gastrointestinal complications improved, with decreasing use or transitory interruption of TEF, but in 4 patients (9.7%), TEF had to be withdrawn. Gastrointestinal complications were more frequent in postsurgical than in nonsurgical patients (p < 0.001). No patients suffered from pulmonary aspiration, and the incidence of pulmonary infection and hepatic dysfunction diminished during TEF.

CONCLUSIONS

Transpyloric enteral feeding is a good method of nutritional support in critically ill children and can be used in patients treated with neuromuscular blocking agents. The frequency and severity of complications and the risks of pulmonary infection and hepatic dysfunction related to TEF are low.

Bronchoesophageal fistula secondary to aspiration of tongue adhesion button in a child with glossoptosis

A newborn boy with obstructive apnea secondary to glossoptosis was treated by securing his tongue to his lower lip. Soon after, the button that served for posterior fixation became detached and was thought to have been evacuated via the digestive tract. Twenty-two months later the infant presented with pneumonia involving the right lower lobe and hemoptysis, causing an acute respiratory distress syndrome (ARDS). After mechanical ventilation was started marked gastric distention was observed. Esophagography and bronchography revealed a fistula between the right main stem bronchus and the esophagus. During surgical repair the plastic fixation button was found in the bronchial orifice of the fistula. Despite surgical correction of the fistula the child died of refractory respiratory failure.

Pediatric basic and advanced life support courses: first experience in Spain

OBJECTIVE

to evaluate the efficiency of the first experience in pediatric basic and advanced life support courses in Spain.

MATERIAL AND METHODS

we have given two pediatric basic life support (PBLS) courses of 8 h each to 52 school teachers and ambulance drivers, and 10 30-h pediatric advanced life support (PALS) courses to 276 health professionals, 62 nurses and 214 physicians (80 pediatricians, 57 pediatric, anesthesiology and intensive care medicine residents, 10 general physicians and 52 emergency physicians). We developed the courses according to the guidelines for pediatric life support from the European Resuscitation Council. We performed an initial and final theoretical written test, continuous practical evaluation and a written survey about the quality of the course.

RESULTS

on PBLS courses, only 12% of practitioners answered at least 80% of the questions in the initial theory test correctly, compared with 77% in the final test (P < 0.001). All the students acquired skills in basic pediatric resuscitation. In the PALS courses, only 30% of practitioners answered at least 75% of the questions in the initial test correctly (35% of physicians and 12% of nurses, P < 0.01); this percentage increased to 95.6% in the final test (96% of physicians and 93.5% of nurses, P < 0.05). Of students, 95% acquired skills in advanced pediatric resuscitation. All students and teachers considered the theoretical and practical formation received adequate.

CONCLUSIONS

basic and advanced pediatric life support courses are a useful educational method for the general population, health professionals, physicians and nurses in theoretical and practical pediatric resuscitation.

Two different maturational stages of natural killer lymphocytes in human newborn infants

The objective of this study was to assess the basis for the diminished natural killer (NK) lymphocyte activity of neonates. We found either severely reduced (63% of 68 neonates) or normal (similar to healthy adult) levels of NK activity. The percentages of cord blood mononuclear cells from the two groups of infants that expressed CD16, a differentiation antigen found in NK cells, were similar and within the range found in peripheral blood mononuclear cells of adults. However, infants with low NK activity had reduced numbers of cells in the CD16+56+ subpopulation, whereas the number of these effector cells present in cord blood mononuclear cells from infants with normal NK activity was within the range found in adults. Recombinant interleukin-2, but not recombinant interferon-gamma, normalized the low NK activity of infants in a dose- and time-dependent manner. Analysis of the pattern of target cell susceptibility to lysis, together with the CD16+CD3- phenotype of the precursor and effector lymphocytes, demonstrated that the induced cytotoxicity was mediated by NK cells. In contrast, NK cells from infants with normal cytotoxic levels exhibited a functional response to interleukin-2 and interferon-gamma similar to that of adults. Our results indicate that NK cells in human neonates go through two different maturational stages.