Study of cytomegalovirus resistance in allogeneic hematopoietic cell transplant recipients. / Estudio de resistencias de citomegalovirus en pacientes receptores de trasplante alogénico de progenitores hematopoyéticos.

INTRODUCTION: Cytomegalovirus (CMV) is the most important opportunistic pathogen associated with transplant. The objective of this study was the characterization of CMV resistance mutations in allogeneic haematopoietic cell transplant recipients (allo-TPH) and the study of associated factors. METHODS: A retrospective study of a cohort of allo-TPH recipients with post-transplant CMV reactivations with stable or increasing viral loads (CV), despite adequate antiviral treatment for at least 2weeks. The study of resistance mutations of the UL97 and UL54 genes was carried out by Sanger sequencing. RESULTS: Refractory CMV infection in our group of allo-TPH patients corresponded with a 21.43% rate of resistant virus infection (3 of 14 patients). All patients with resistance mutations had multiple reactivation episodes (P-value .01). The mutations found were A594V and H520Q in the UL97 gene that confers high-grade resistance to ganciclovir (GCV). One of the 3 cases with antiviral resistance was documented with a low VL (< 1000 copies/ml) and short accumulated GCV treatment (41 days). CONCLUSION: Most of the failures in the treatment of CMV were possibly due to clinical resistance; the lack of satisfactory response to antiviral treatment is not always accompanied by virological resistance. However, the appearance of resistances can occur early after the start of the treatment and with VL below 1000 copies / ml. The number of episodes of reactivation was higher among patients with virological resistance than those who did not.

Improvement in detecting cytomegalovirus drug resistance mutations in solid organ transplant recipients with suspected resistance using next generation sequencing.

OBJETIVES: The aim of this study was to identify CMV drug resistance mutations (DRM) in solid organ transplant (SOT) recipients with suspected resistance comparing next-generation sequencing (NGS) with Sanger sequencing and assessing risk factors and the clinical impact of resistance. METHODS: Using Sanger sequencing as the reference method, we prospectively assessed the ability of NGS to detect CMV DRM in the UL97 and UL54 genes in a nationwide observational study from September 2013 to August 2016. RESULTS: Among 44 patients recruited, 14 DRM were detected by Sanger in 12 patients (27%) and 20 DRM were detected by NGS, in 16 (36%). NGS confirmed all the DRM detected by Sanger. The additional six mutations detected by NGS were present in <20% of the sequenced population, being located in the UL97 gene and conferring high-level resistance to ganciclovir. The presence of DRM by NGS was associated with lung transplantation (p = 0.050), the administration of prophylaxis (p = 0.039), a higher mean time between transplantation and suspicion of resistance (p = 0.038) and longer antiviral treatment duration before suspicion (p = 0.024). However, the latter was the only factor independently associated with the presence of DRM by NGS in the multivariate analysis (OR 2.24, 95% CI 1.03 to 4.87). CONCLUSIONS: NGS showed a higher yield than Sanger sequencing for detecting CMV resistance mutations in SOT recipients. The presence of DRM detected by NGS was independently associated with longer antiviral treatment.

Detection of cytomegalovirus drug resistance mutations in solid organ transplant recipients with suspected resistance.

BACKGROUND: Current guidelines recommend that treatment of resistant cytomegalovirus (CMV) in solid organ transplant (SOT) recipients must be based on genotypic analysis. However, this recommendation is not systematically followed. OBJECTIVES: To assess the presence of mutations associated with CMV resistance in SOT recipients with suspected resistance, their associated risk factors and the clinical impact of resistance. STUDY DESIGN: Using Sanger sequencing we prospectively assessed the presence of resistance mutations in a nation-wide prospective study between September 2013-August 2015. RESULTS: Of 39 patients studied, 9 (23%) showed resistance mutations. All had one mutation in the UL 97 gene and two also had one mutation in the UL54 gene. Resistance mutations were more frequent in lung transplant recipients (44% p=0.0068) and in patients receiving prophylaxis ≥6 months (57% vs. 17%, p=0.0180). The mean time between transplantation and suspicion of resistance was longer in patients with mutations (239 vs. 100days, respectively, p=0.0046) as was the median treatment duration before suspicion (45 vs. 16days, p=0.0081). There were no significant differences according to the treatment strategies or the mean CMV load at the time of suspicion. Of note, resistance-associated mutations appeared in one patient during CMV prophylaxis and also in a seropositive organ recipient. Incomplete suppression of CMV was more frequent in patients with confirmed resistance. CONCLUSIONS: Our study confirms the need to assess CMV resistance mutations in any patient with criteria of suspected clinical resistance. Early confirmation of the presence of resistance mutations is essential to optimize the management of these patients.

[Chryseobacterium spp., a new opportunistic pathogen associated with cystic fibrosis?]. / Chryseobacterium spp., ¿nuevo patógeno oportunista asociado a fibrosis quística?

INTRODUCTION: There is an increase in the isolation of non-fermenting gramnegative bacilli in patients with cystic fibrosis (CF). The present study evaluates the frequency of isolates of Chryseobacterium spp., analyzing its characteristics, resistance patterns and clinical outcome of patients. METHODS: It has been collected all respiratory isolates of Chryseobacterium spp. of patients attended in the CF unit of Hospital de la Princesa for three years (march 2009-march 2012). For phenotypic and genotypic identification and sensitivity study conventional methodology was used. For the assessment of the patients lung function was considered the forced expiratory volume in one second (FEV1) and the results were analyzed with SPSS. RESULTS: There was an increase in the incidence of Chryseobacterium spp. with 17 isolates from 9 patients. Three patients had chronic colonization by this microorganism and one showed significant impairment of lung function. Seven patients showed also colonization with Staphylococcus aureus and 4 of them with Pseudomonas aeruginosa. CONCLUSION: Chryseobacterium spp. should be considered as a new emerging opportunistic pathogen in patients with CF. It is essential the clinical and microbiological monitoring of this group of patients for detection of Chryseobacterium spp. colonization and to prevent the chronic infection. In these circumstances it must assess its possible eradication, though its clinical impact is unknown. Cotrimoxazole being the best treatment option.

Outcome of patients with serology suggestive of past hepatitis B virus infection during antitumor necrosis factor therapy for psoriasis.

BACKGROUND: Recently, the reactivation during treatment with tumor necrosis factor (TNF) blockers has exceptionally been described in patients with hepatitis B virus (HBV) antigen-negative (HBsAg). The objective was to evaluate the influence of anti-TNF agents in patients with psoriasis and serology suggesting past hepatitis B state. METHODS: The inclusion criteria were chronic plaque psoriasis treated with anti-TNF therapy, HBsAg-negative, and HBcAb-positive. We gathered the demographic data and type and duration of anti-TNF agent. Serum aminotransferase levels and HBV serologic status were requested at baseline and during follow-up. RESULTS: We have included 13 patients (four women, nine men) (mean age of 62.1 years). The agent was etanercept in seven cases, infliximab in four patients, and adalimumab in the other two. The mean duration of TNF therapy was 28.6 months. None of them became HBsAg-positive. Neither signs nor symptoms of acute hepatitis were reported. CONCLUSION: The management of HBsAg-negative patients is unresolved. Only nine cases of HBV reactivation during treatment with TNF blockers have been reported. Despite the low risk of reactivation in these patients, we recommend the monitoring of serum aminotransferase levels, HBsAb titers, HBsAg and, if possible, viral load.

[Pneumococcal bacteremia in adult patients at a hospital in Madrid: serotypes and susceptibility]. / Bacteriemia neumocócica en pacientes adultos de un hospital de Madrid: serotipos y sensibilidad antibiótica.

INTRODUCTION: The aim of this study is to describe the distribution of Streptococcus pneumoniae serotypes, its antimicrobial susceptibility profiles and the relation with vaccines in pneumococcal invasive strains isolated from blood cultures of adult patients. METHODS: All pneumococci isolated (67 strains) from blood cultures were serotyped by latex agglutination (Pneumotest latex) and Quellung reaction (Statens Serum Institut, Denmark). Antimicrobial susceptibility testing to penicillin (PEN), cefotaxime (CT), erythromycin (ERY) and levofloxacin (LEV) was performed by the E-test method (Biomèrieux, France). RESULTS: Among the 67 strains isolated, the most prevalent serotypes were 22F (11.9%) and 3 (11.9%), the second most frequent were 7F (7.5%) and 19A (7.5%). The coverage of the strains by the pneumococcal 7-valent conjugate vaccine (VNC7V), pneumococcal 13-valent conjugate vaccine (VNC13V) and pneumococcal 23-valent polysaccharide (VNP23V) were 16, 49 and 82%, respectively. Serotypes 22F and 3 were responsible for 14 of the 48 episodes of pneumonia with bacteremia (29.2%) and only 2 of the 19 episodes (10.5%) of bacteremia without pneumonia. According to the 2007 CLSI criteria, 12 strains (17.9%) were non-susceptible to penicillin. Eleven of this 12 strains (91.7%) were resistant to erythromycin, simultaneously. CONCLUSIONS: The most common serotypes were 22F, 3, 7F y 19A. Three of them (3, 7F y 19A) are serotypes that are covered by the new VNC13V but not by VNC7V. Serotype 22F is a serotype emergent that is not covered by the VNC7V. The percentage of non-susceptibility to penicillin and resistance to erythromycin was comparable to the percentage reported in our country.

Abdominal abscess due to NDM-1-producing Klebsiella pneumoniae in Spain.

We describe a clinical case of an abdominal abscess due to NDM-1-producing Klebsiella pneumoniae in a 35-year-old Spanish patient after hospitalization in India for perforated appendicitis and peritonitis. The strain belonged to the MLST type 231 and had multiple additional antibiotic resistance genes such as bla(CTX-M-15), armA methylase, aac(6')-Ib-cr, dfrA12, sul1 and qnrB and lack of porin genes ompK35 and ompK36. The patient was cured after abscess drainage.