Jesús Saavedra-Lozano

Changing trends in acute osteomyelitis in children: impact of methicillin-resistant Staphylococcus aureus infections.

Background: Staphylococcus aureus remains the most common etiologic agent of acute osteomyelitis in children. Recently, methicillin-resistant S. aureus (MRSA) has emerged as a major pathogen. Methods: Records of all children admitted with acute osteomyelitis from January 1999 to December 2003 were reviewed. For the comparative analysis, the study population was evenly distributed in 2 periods: period A, January 1999 to June 2001; n = 113; and period B, July 2001 to December 2003; n = 177. In addition, clinical findings of MRSA osteomyelitis were compared with non-MRSA osteomyelitis, including methicillin-sensitive S. aureus infections. Results: Two hundred ninety children (60% male subjects) with acute osteomyelitis were identified. Median (25th-75th percentile) age at diagnosis was 6 years (range, 2-11 years). Significant clinical findings included the following: localized pain (84%), fever (67%), and swelling (62%). Affected bones included the following: foot (23%), femur (20%), tibia (16%), and pelvis (7%). Thirty-seven percent of blood cultures were positive, and a bacterial isolate was obtained in 55% of cases. Bacteria most frequently isolated included the following: methicillin-sensitive S. aureus (45%) (57% in period Avs 40% in period B), MRSA (23%) (6% in A vs 31% in B; P < 0.001), Streptococcus pyogenes (6%), and Pseudomonas aeruginosa (5%). Children with MRSA compared with those with non-MRSA osteomyelitis had significantly greater erythrocyte sedimentation rate and C-reactive protein values on admission and increased length of hospital stay, antibiotic therapy, and overall rate of complications. We observed significant changes in antibiotic therapy related to increased use of agents with activity against MRSA. Conclusions: Methicillin-resistant S. aureus was isolated more frequently in the second study period and was associated with worse clinical outcomes. Level of Evidence: II. Retrospective study.

Anti-Respiratory Syncytial Virus (RSV) Neutralizing Antibody Decreases Lung Inflammation, Airway Obstruction, and Airway Hyperresponsiveness in a Murine RSV Model

ABSTRACT Numerous studies have described a strong association between respiratory syncytial virus (RSV) infection in infancy and the development of recurrent wheezing and airway hyperresponsiveness. We evaluated the effect of an anti-RSV neutralizing monoclonal antibody (palivizumab) on different aspects of RSV disease by using a murine model. BALB/c mice were intranasally inoculated with RSV A2. Palivizumab or an isotype-matched control antibody was administered once at 24 h before inoculation, 1 h after inoculation, or 48 h after inoculation. Regardless of the timing of administration, all mice treated with the neutralizing antibody showed significantly decreased RSV loads in bronchoalveolar lavage (BAL) and lung specimens compared with those of infected controls. Pulmonary histopathologic scores, airway obstruction measured by plethysmography, and airway hyperresponsiveness after methacholine challenge were significantly reduced in mice treated with the anti-RSV antibody 24 h before inoculation compared with those for untreated controls. Concentrations of interferon-gamma, interleukin-10, macrophage inflammatory protein 1α, regulated on activation normal T-cell expressed and secreted (RANTES), and eotaxin in BAL fluids were also significantly reduced in mice treated with palivizumab 24 h before inoculation. This study demonstrates that reduced RSV replication was associated with significant modulation of inflammatory and clinical markers of acute disease severity and significant improvement of the long-term pulmonary abnormalities. Studies to determine whether strategies aimed at preventing or reducing RSV replication could decrease the long-term morbidity associated with RSV infection in children should be considered.

Cerebrospinal fluid and plasma concentrations of proinflammatory mediators in human immunodeficiency virus-infected children.

Background. The pathogenesis of HIV encephalopathy is poorly understood especially in children. Studies suggest that HIV replication and the release of proinflammatory mediators in the central nervous system contribute to the pathogenesis of HIV dementia in adults. Methods. Cerebrospinal fluid (CSF) and plasma samples from 23 HIV-infected children were longitudinally analyzed at Weeks 0, 8, 16 and 48 for HIV RNA and concentrations of the following proinflammatory mediators: monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha, regulated upon activation, normal T cell expressed and secreted (RANTES), macrophage-inflammatory protein (MIP)-1-alpha, MIP-1-beta and matrix metalloproteinase-9 (MMP-9). Results. All 23 children had detectable concentrations of MCP-1 in the CSF at all time points evaluated. However, of the remaining of proinflammatory mediators measured in CSF at baseline, only a few children had detectable concentrations: tumor necrosis factor-alpha, n = 1; RANTES, n = 5; MMP-9, n = 9; MIP-1-alpha and MIP-1-beta, n = 0. A reduction from baseline to Week 48 was observed in CSF concentrations of MCP-1 and, among children with detectable values, MMP-9, which paralleled declines in CSF HIV RNA. Conclusion. These results suggest that MCP-1 and MMP-9 may be involved in the pathogenesis of central nervous system disease in HIV-infected children.

High Drug Resistance Prevalence among Vertically HIV-Infected Patients Transferred from Pediatric Care to Adult Units in Spain

Background Antiretroviral treatment (ART) has contributed to increased life expectancy of HIV-1 infected children. In developed countries, an increasing number of children reaching adulthood are transferred to adult units. The objectives were to describe the demographic and clinical features, ART history, antiviral drug resistance and drug susceptibility in HIV-1 perinatally infected adolescents transferred to adult care units in Spain from the Madrid Cohort of HIV-1 infected children. Methods Clinical, virological and immunological features of HIV-1 vertically infected patients in the Madrid Cohort of HIV-infected children were analyzed at the time of transfer. Pol sequences from each patient were recovered before transfer. Resistance mutations according to the InternationaI AIDS Society 2011 list were identified and interpreted using the Stanford algorithm. Results were compared to the non-transferred HIV-1 infected pediatric cohort from Madrid. Results One hundred twelve infected patients were transferred to adult units between 1997 and 2011. They were mainly perinatally infected (93.7%), with a mean nadir CD4+-T-cells count of 10% and presented moderate or severe clinical symptoms (75%). By the time of transfer, the mean age was 18.9 years, the mean CD4+T-cells count was 627.5 cells/ml, 64.2% presented more than 350 CD4+T-cells/ml and 47.3% had ≤200 RNA-copies/ml. Most (97.3%) were ART experienced receiving Highly Active ART (HAART) (84.8%). Resistance prevalence among pretreated was 50.9%, 76.9% and 36.5% for Protease Inhibitors (PI), Nucleoside Reverse Transcriptase Inhibitors (NRTI) and Non-NRTI (NNRTI), respectively. Resistance mutations were significantly higher among transferred patients compared to non-transferred for the PI+NRTI combination (19% vs. 8.4%). Triple resistance was similar to non-transferred pediatric patients (17.3% vs. 17.6%). Conclusion Despite a good immunological and virological control before transfer, we found high levels of resistance to PI, NRTI and triple drug resistance in HIV-1 infected adolescents transferred to adult units.

An Anti-CD45RO Immunotoxin Kills Latently Infected Human Immunodeficiency Virus (HIV) CD4 T Cells in the Blood of HIV-Positive Persons

Highly active antiretroviral therapy has decreased the morbidity and mortality of human immunodeficiency virus (HIV) infection, but latently infected cells remain for prolonged periods. CD4(+) CD45RO(+) T cells are a major latent virus reservoir in HIV-infected persons. Replication-competent, latently HIV-infected T cells can be generated in vitro by infecting peripheral blood mononuclear cells with HIV and then eliminating the HIV-producing cells with an anti-CD25 immunotoxin (IT). The CD25(-) latently infected cells then can be eliminated with an anti-CD45RO IT. This study determined whether this IT also could kill latently infected CD4 T cells from HIV-infected persons with or without detectable plasma viremia. The results show that ex vivo treatment of cells from HIV-positive persons by anti-CD45RO IT reduces the frequency of both productively and latently infected cells. In contrast, CD4(+) CD45RA(+) naive T cells and a proportion of CD4(+) CD45RO(lo) memory T cells are spared.

Comparison of Mycobacterium lentiflavum and Mycobacterium avium-intracellulare Complex Lymphadenitis

Background: Mycobacterium lentiflavum is considered a rare pathogen causing nontuberculous mycobacterial (NTM) lymphadenitis. Methods: A multicenter, retrospective study was performed in immunocompetent children <14 years of age with microbiologically confirmed NTM lymphadenitis treated at 6 hospitals in Madrid, Spain, during 2000–2010. We compared children with M. lentiflavum and Mycobacterium avium-intracellulare complex infection. Results: Forty-five microbiologically confirmed NTM lymphadenitis patients were identified: 19 (45.2%) caused by M. avium-intracellulare complex, 17 (40.5%) by M. lentiflavum, 1 by both and 5 by other mycobacteria. Out of 17 M. lentiflavum cases, 14 were diagnosed in the past 5 years. Regarding M. lentiflavum cases, median age was 23 months. Submandibular nodes were the most frequently involved (76.5%), with multiple locations seen in 41% of the children and spontaneous drainage in 41% of them. Drug susceptibility tests were performed in 14 isolates and showed a complete susceptibility to clarithromycin and cycloserine, whereas 93% were resistant to rifampin, 33% to quinolones and full resistance to other tested antimycobacterial drugs was detected. All but 1 child required surgery and 11 were treated additionally with various drug combinations. Total resolution was achieved in 50% of children within 6 months. Compared with M. avium-intracellulare complex cases, children were younger and laterocervical nodes were significantly less frequently involved. No statistically significant differences were found related to clinical characteristics, treatment and outcome. Conclusions: M. lentiflavum is an emerging pathogen producing NTM lymphadenitis in Madrid.

Initiating highly active antiretroviral therapy in human immunodeficiency virus type 1-infected children in europe and the United States : Comparing clinical practice to guidelines and literature evidence

Several guidelines are available to guide the initiation of highly active antiretroviral therapy (HAART) in human immunodeficiency virus (HIV)-infected children. The recommendations in these guidelines show significant variability. Because there is no well-established evidence on when to start HAART, it is left to the discretion of the pediatrician which guidelines to follow. We conducted a survey concerning the indications for starting antiretroviral therapy among pediatricians involved in the treatment of HIV-infected patients in Europe and the United States. We compared the results of this survey with the guidelines available at the time, the recently adapted guidelines and literature evidence. Our results indicate that in clinical practice HAART was initiated at higher viral loads and lower CD4 counts than recommended by the guidelines. American guidelines recommended and still recommend more aggressive treatment than the European guidelines, and this is reflected in clinical practice. Until recently all guidelines were based on long term risk analyses of progression to acquired immunodeficiency syndrome (AIDS) and death performed in cohort data. A recent short term risk analysis makes it possible to calculate the 6 or 12-month risk for progression to AIDS or death for an individual child. Because viral load and CD4 count are typically measured every 3 months, one can argue that it is clinically more relevant to base the decision of when to start HAART on the short term probability of disease progression. Guidelines in Europe are now based on this type of analysis. The American guidelines only adopted the thresholds for CD4 and viral load. The short term risk analysis also shows that the risk for developing AIDS varies markedly with age. This should be reflected in all guidelines. Determining the acceptable risk of disease progression is difficult and influenced by patient-, doctor- and culture-related factors. The controversy over whether or not to treat asymptomatic infants is unresolved as well. All infants have a very high risk of disease progression regardless of their viral load or CD4 count, but lifelong treatment with a potential for significant toxicities and risk of developing resistance is also not an appealing option. We recommend an attempt to achieve a consensus among the different working groups to reduce the number of different guidelines, which should be based on the literature evidence. Because all risk analyses are based on information from the pre-HAART era, a head-to-head trial comparing early versus deferred HAART would be useful. This may be difficult to accomplish. The first step could be an analysis of retrospective data from collaborative cohort data.

Interferon-γ release assay for the diagnosis of tuberculosis in children

Aims To compare the QuantiFERON-TB GOLD In Tube test (QTF) and the tuberculin skin test (TST) in children. Methods A prospective study was carried out in nine hospitals in Madrid, Spain. TST and QTF were performed in immigrants, tuberculosis (TB) contacts and patients with TB disease (TBD). Results 459 children were included. Disagreement between the tests was more frequently observed among latent tuberculosis infection (LTBI) cases (54%; 38/70) than in non-infected or TBD cases (0.8%; 3/369) (p<0.01). There were more BCG-vaccinated children among LTBI cases with negative QTF (76%) than among LTBI cases with positive QTF (40%) (p<0.001). Agreement between tests in BCG-vaccinated children was lower than in non-vaccinated cases (p<0.05). Tests in TB exposed patients showed better agreement than in non-exposed children (p<0.05). Conclusions Agreement of both tests was excellent in TBD cases, non-vaccinated children and non-infected patients. A significant number of QTF negative results were observed among LTBI cases, especially in BCG-vaccinated children. Agreement was better in exposed children.

Zidovudine, Lamivudine, and Abacavir Have Different Effects on Resting Cells Infected with Human Immunodeficiency Virus In Vitro

ABSTRACT We have previously described an in vitro model for the evaluation of the effects of different immunomodulatory agents and immunotoxins (ITs) on cells latently infected with human immunodeficiency virus (HIV). We demonstrated that latently infected, replication-competent cells can be generated in vitro after eliminating CD25+ cells with an IT. Thus, by selectively killing the productively infected cells with an anti-CD25 IT we can generate a population of latently infected cells. CD25− cells generated in this manner were treated with nucleoside analog reverse transcriptase inhibitors and subsequently activated with phytohemagglutinin in the presence of the drugs. The antiviral activities of zidovudine (ZDV), lamivudine (3TC), and abacavir (ABC) were evaluated by using this model. 3TC and ABC demonstrated significant activity in decreasing HIV production from recently infected resting cells following their activation, whereas the effect of ZDV was more modest. These results suggest that the differences in antiviral activity of nucleoside analogs on resting cells should be considered when designing drug combinations for the treatment of HIV infection. The model presented here offers a convenient alternative for evaluating the mechanism of action of new antiretroviral agents (J. Saavedra, C. Johnson, J. Koester, M. St. Claire, E. Vitteta, O. Ramilo, 37th Intersci. Conf. Antimicrob. Agents Chemother., abstr. I-59, 1997).

Isolated cerebellar edema and obstructive hydrocephalus in a child with cerebral malaria

An important complication of cerebral malaria is increased intracranial pressure which, when severe, is associated with high mortality or neurologic sequelae. We describe a 7-month-old child with cerebral malaria for whom cerebellar edema and obstructive hydrocephalus were initial radiologic findings. Despite significant hydrocephalus, the child had normal intracranial pressure during the course of the infection, and he recovered with minimal sequelae.