Santiago Melón

Etiology of Sporadic Cases of Pediatric Acute Gastroenteritis in Asturias, Spain, and Genotyping and Characterization of Norovirus Strains Involved

ABSTRACT From November 2000 to October 2001, a reverse transcription-PCR using primers directed to the norovirus RNA polymerase coding region was included in a viral and bacterial routine screening to diagnose sporadic cases of acute gastroenteritis among children in Asturias, Spain. The role of noroviruses (8.6% of the positively diagnosed cases) as the cause of sporadic pediatric gastroenteritis was evaluated with respect to the detection rates of other gastroenteritis-associated viruses and bacteria. The results indicated that noroviruses were less common than rotaviruses (36.9%), Campylobacter spp. (28.8%), and Salmonella spp. (18.4%) but more frequent than astroviruses (4.3%), adenoviruses (3.8%), and Yersinia spp. (2.2%). Mixed infections involving noroviruses were rarely observed (0.5%). The presence of a norovirus-associated pediatric gastroenteritis peak in summer, as well as the complete absence of norovirus-associated cases in colder months, challenges the view that norovirus infections exclusively have wintertime seasonality. On the other hand, phylogenetic analysis of the amplified fragments showed that the norovirus strains responsible were closely related. A further study using the full-length capsid region showed that these strains could be included into genogroup II, Bristol/Lorsdale cluster, and were closely related to the 1995 and 1996 U.S. subset of strains associated with outbreaks recorded worldwide between 1995 and 1996.

Role of Metapneumovirus in Viral Respiratory Infections in Young Children

ABSTRACT The contribution of human metapneumovirus (hMPV) relative to that of other respiratory viruses as a cause of respiratory infections in children less than 1 year old has been evaluated. From October 2003 to April 2004, nasopharyngeal samples from 211 children less than 1 year old were analyzed to detect respiratory viruses. Respiratory syncytial virus (RSV) was the predominant virus isolated (96 children [45.5%]), followed by influenza A virus, parainfluenza virus, adenovirus, cytomegalovirus, and herpes simplex virus type 1, which were only occasionally detected. From January 2004 to April 2004, a nested retrotranscription-PCR, using in-house primers directed to the matrix protein gene of hMPV, was carried out on samples in which no other viruses were detected. hMPV was detected in 18 (16.2%) children, indicating that this virus was the second-most-frequent cause of viral respiratory infections in children less than 1 year old. The rate of hospitalization for RSV- and hMPV-infected children was higher than 75%. While RSV had a peak from December to February, hMPV was increasingly detected from January to April. The mean age of hMPV-infected children (6.44 ± 3.64 [mean ± standard deviation] months) was significantly higher than that of RSV-infected children (3.99 ± 2.96 [mean ± standard deviation] months). On the other hand, 64.3% of the RSV-infected children and 12.5% of the hMPV-infected children showed high levels of C-reactive protein. Although several authors have reported that clinical symptoms of hMPV-positive patients mirrored those of RSV-positive patients, differences between the two viruses can be found.

Herpes Simplex Virus Encephalitis in a Renal Transplant Patient: Diagnosis by Polymerase Chain Reaction Detection of HSV DNA

A case of herpes simplex virus (HSV) encephalitis with disseminated primary HSV infection in a renal transplant patient is described. The diagnosis of the disease was achieved by nested polymerase chain reaction (PCR)-DNA in cerebrospinal fluid (CSF). Other diagnostic measures (immunoglobulin [Ig] M and virological cultures both in blood and CSF) were negative. Blood IgG gave a false-positive signal. Although ganciclovir is not the drug of choice, its concomitant administration in our patient as a prophylactic measure against CMV infection may have decreased the usual severity normally expected in this kind of primary HSV infection. The subsequent increase in ganciclovir dose to full therapeutic range, which was implemented before the diagnosis was achieved, led to the disappearance of symptoms. The detection of PCR-DNA in CSF will probably become the diagnostic method of choice. One of its great advantages, in addition to its diagnostic reliability, is that it may obviate the performance of many cerebral biopsies.

Long-term outcome in Caucasian patients with chronic hepatitis B virus infection after HBsAg seroclearance.

The natural course after hepatitis B surface antigen (HBsAg) seroclearance in Caucasian patients with chronic hepatitis B virus (HBV) infection is not well‐defined. To investigate the clinical characteristics and outcome in a series of European Caucasian patients with chronic HBV infection according to HBsAg response over time.

Human Papillomavirus Infection in a Male Population Attending a Sexually Transmitted Infection Service

Objective Human Papillomavirus (HPV) infection in men may produce cancer and other major disorders. Men play an important role in the transmission of the virus and act as a reservoir. The aim of this study was to determine the HPV-genotypes and their prevalence in a group of men attending a Sexually Transmitted Infection service. Patients and Samples Between July 2002 and June 2011, 1392 balanopreputial, 435 urethral, 123 anal, and 67 condyloma lesions from 1551 men with a mean age of 35.8±11.3 years old (range: 17–87) were collected for HPV-DNA testing. Methods A fragment of the L1-gene and a fragment of the E6/E7-genes were amplified by PCR. Positive samples were typed by hybridization. Results The HPV genome was detected in 36.9% (486/1318) balanopreputial and in 24.9% (101/405) urethral (p<0.0001) swabs from 38.1% (538) of 1469 men. Co-infections were present in 5.4% (80/1469) of cases. HPV was found in 43.9% (373/850) of men younger than 35 vs. 31.7% (187/589) of men aged >35. HPV was found in 59.4% (104) of 165 men with lesions (macroscopic or positive peniscopy), and in 22.8% (61/267) without clinical alterations. HPV was also detected in 71.4% (40/56) men with condylomata and in 58.7% (64/109) of men with positive peniscopy. Conclusions HPV prevalence in men was high and decreased with age. HPV was found more frequently in balanopreputial than in urethral swabs. There was a low rate of co-infections. Low-risk HPV vaccine genotypes were the most recurrent especially in younger. Although HPV has been associated with clinical alterations, it was also found in men without any clinical presentation. Inclusion of men in the national HPV vaccination program may reduce their burden of HPV-related disease and reduce transmission of the virus to non-vaccinated women.

Prevalence, evolution, and features of infection with human papillomavirus: A 15-year longitudinal study of routine screening of a women population in the north of Spain

Determination of the prevalence of type‐specific human papillomavirus (HPV) is important for the development of new vaccines and to prevent malignancy. The objective of this study was to determine HPV infection in two areas in the north of Spain, and their evolution in the last 15 years. Between 1991 and 2007, 7,930 fresh cervical swabs were obtained from 5,554 women (37.8 ± 11.8 years old). From them, 425 have been followed‐up for an average of 3.7 ± 2.08 years after sampling (range 2–14.6), and 71 for 7.7 ± 2.2 years (range 5–14). Methods based on polymerase chain reaction (PCR) were carried out. Samples from 1,598 (28.8%) women were positive for HPV: 40.9% were under 25 years of age, 34.2% in the 25–35 year age group, 27.2% in the 36–45 year age group, and 19.6% older than 45 years (P < 0.001). HPV was found in 34.4% of the women with cytological alterations versus 23% of women without cervical changes (P < 0.0001). HPV‐16 was present in 25.8% of the women, although the study identified 26 different HPV genotypes. After 3 years of follow‐up, HPV remained or became undetectable in 87% of the cases, and in 5 years 70.3%. The prevalence of HPV is associated with younger women and women with cytological changes in the cervix. Although HPV‐16 is more prevalent, HPV types not included in available vaccines were found the most commonly. The low 3‐year (even 5‐year) cumulative incidence rate of HPV infection suggests that cervical screening every 3 (or even 5) years is safe and effective. J. Med. Virol. 82:597–604, 2010.

Prevalence of HPV 16 and HPV 18 lineages in Galicia, Spain.

Genetic variants of human papillomavirus types 16 and 18 (HPV16/18) could differ in their cancer risk. We studied the prevalence and association with high-grade cervical lesions of different HPV16/18 variant lineages in a case-control study including 217 cases (cervical intraepithelial neoplasia grade 2 or grade 3 or worse: CIN2 or CIN3+) and 116 controls (no CIN2 or CIN3+ in two-year follow-up). HPV lineages were determined by sequencing the long control region (LCR) and the E6 gene. Phylogenetic analysis of HPV16 confirmed that isolates clustered into previously described lineages: A (260, 87.5%), B (4, 1.3%), C (8, 2.7%), and D (25, 8.4%). Lineage D/lineage A strains were, respectively, detected in 4/82 control patients, 19/126 CIN3+ cases (OR = 3.1, 95%CI: 1.0–12.9, p = 0.04), 6/1 glandular high-grade lesions (OR = 123, 95%CI: 9.7–5713.6, p<0.0001), and 4/5 invasive lesions (OR = 16.4, 95%CI: 2.2–113.7, p = 0.002). HPV18 clustered in lineages A (32, 88.9%) and B (4, 11.1%). Lineage B/lineage A strains were respectively detected in 1/23 control patients and 2/5 CIN3+ cases (OR = 9.2, 95%CI: 0.4–565.4, p = 0.12). In conclusion, lineages A of HPV16/18 were predominant in Spain. Lineage D of HPV16 was associated with increased risk for CIN3+, glandular high-grade lesions, and invasive lesions compared with lineage A. Lineage B of HPV18 may be associated with increased risk for CIN3+ compared with lineage A, but the association was not significant. Large well-designed studies are needed before the application of HPV lineage detection in clinical settings.

Disseminated Herpes simplex Virus Infection in a Renal Transplant Patient as Possible Cause of Repeated Urinary Extravasations

Disseminated herpes simplex virus type 2 (HSV-2) infections are infrequent in patients receiving organ transplants, but usually have a poor outcome. We describe the case of a renal transplant patient who developed a disseminated HSV-2 infection with repeated urinary extravasations. The diagnosis was carried out using a multiplex polymerase chain reaction nested assay and it suggested HSV-2 as a possible cause of repeated urinary fistulas.

Control of Cytomegalovirus Disease in Renal Transplant Patients Treated with Prednisone, Azathioprine and Cyclosporine Using Intensive Monitoring and Decreased Immunosuppression

Background: The aim of this trial was to study the effectiveness of intensive monitoring, together with an early decrease in immunosuppression, in reducing the prevalence of CMV disease in renal transplant recipients treated with prednisone, azathioprine and cyclosporine. Methods: From 1/95 to 11/97 a prospective, longitudinal study was conducted among 146 consecutive, unselected, renal transplant patients in our unit. Only 96 patients whose immunosuppressive regimens consisted of prednisone, azathioprine and cyclosporine and whose follow-up period was greater than 4 months were included in the study. Preemptive therapy was administered to 27 high-risk patients. CMV antigenemia (CMV-AG) and other virological tests were performed weekly for the first 4 posttransplant months. The immunosuppression was decreased when the first positive CMV-AG was detected. Azathioprine was completely withdrawn when the CMV-AG count was greater than 10 cells per 105 PBLs. The cyclosporine dose was gradually decreased in the next 4 weeks, but it was not withdrawn in any patient. The prednisone dose was modified according to the immunosuppressive protocol. Results: 53% (51/96) of the patients had positive CMV-AG on at least one occasion. The dose of azathioprine was decreased after CMV-AG detection in 41/51 (80.4%) patients and it was completely withdrawn in 23 of these (45%). The mean decrease in the dose of azathioprine was 73 ± 31 (25–175) mg, a mean percentage decrease of 76 ± 27% (25–100%). The dose of cyclosporine was progressively decreased during the 4 weeks after detection of the first CMV-AG (mean cyclosporine levels: 210 ± 66, 196 ± 54 and 164 ± 36 ng/ml at the time of first CMV-AG detection, 2 and 4 weeks respectively, p < 0.0001, repeated measures analysis of variance). None of the 45 patients without CMV-AG and only 2 of 51 (3.9%) patients with CMV-AG developed symptomatic CMV disease (2% of the total). CMV disease was of moderate intensity in both patients. Only 3/51 (5.8%) patients developed acute rejection after the first CMV-AG detection in the 4 posttransplant months. Conclusion: The results of this study suggest that intensive monitoring and an early reduction of immunosuppression, together with preemptive therapy in high-risk patients, is effective in diminishing the prevalence and severity of CMV disease.

Noroviruses as cause of gastroenteritis in elderly patients

Background and aims: Gastroenteritis is one of the infections which are particularly important in elderly people. Knowledge of the main pathogens causing gastroenteritis in this group of patients, whose number will dramatically increase in coming decades, is essential. The contribution of group A rotavirus, adenovirus types 41 and 42, norovirus and astrovirus as causes of gastroenteritis among patients of all ages, especially those with over 65 was evaluated over an extended time period. Methods: A total of 4024 fecal samples, collected during seven seasons (October 2000 to September 2007), were tested with a commercial immunoassay (rotavirus) and an “in house” nested RT-PCR (adenovirus, norovirus and astrovirus). Results: Although norovirus was the second most common cause of gastroenteritis (7.9%) in the total population, it was predominant in the age group over the age of 6, causing 7.2% of gastroenteritis in the 6–16-year-old group, 8.6% in the 16–64-year-old group, and 11.1% in the >65-year group (p=0.001). In the last age group, norovirus was the most frequently detected (11.1%), followed by adenovirus (7.4%), astrovirus (3.6%) and rotavirus (3.3%) (p<0.0001). In addition, norovirus was rarely found in association with other viruses. Conclusions: Our data suggest that the elderly are highly vulnerable to certain infections, and indicate the need to introduce simple tests for an early identification of norovirus in cases of gastroenteritis affecting elderly patients, improving patient care by reducing unnecessary treatments and hospital stays.