Clinical Manifestations and Outcomes in Disease-Modifying Antirheumatic Drug-Naive Adult Patients with Chronic Chikungunya Arthritis.

Most studies on chronic chikungunya virus (CHIKV) arthritis include patients treated with disease-modifying antirheumatic drugs (DMARDs), likely altering the expression of clinical manifestations and outcome. Therefore, we sought to evaluate the clinical features and correlates in DMARD-naive patients with chronic CHIKV arthritis. We conducted a case-control study in adult patients with serologically confirmed CHIKV infection in Puerto Rico. Demographic features, clinical manifestations, comorbidities, disease activity (per Clinical Disease Activity Index [CDAI]), functional status (per Health Assessment Questionnaire Disability Index [HAQ-DI]), and pharmacologic treatment were ascertained. Patients with and without chronic CHIKV arthritis were compared. Furthermore, a sub-analysis was performed among patients with chronic CHIKV who presented with mild disease activity versus moderate-to-high disease activity at study visit. In total, 61 patients were studied; 33 patients had chronic arthritis and 28 had resolved arthritis. Patients with chronic arthritis had significantly more diabetes mellitus, chronic back pain, and fever, tiredness, and myalgias on the acute phase. The mean (SD) HAQ score was 0.95 (0.56), and 57.6% had moderate-to-high disease activity. Patients with moderate-to-high disease activity had higher scores in overall HAQ-DI and HAQ-DI categories (dressing and grooming, arising, hygiene, reaching, and activities) than in those with mild activity. In conclusion, in this group of DMARD-naive patients with chronic CHIKV arthritis, nearly 58% had moderate-to-high disease activity and had substantial functional disability. Diabetes mellitus, chronic back pain, and some manifestations on acute infection were associated with chronic CHIKV arthritis.

Genetic environment of the KPC gene in Acinetobacter baumannii ST2 clone from Puerto Rico and genomic insights into its drug resistance.

Carbapenems are considered the last-resort antibiotics to treat infections caused by multidrug-resistant Gram-negative bacilli. The Klebsiella pneumoniae carbapenemase (KPC) enzyme hydrolyses ß-lactam antibiotics including the carbapenems. KPC has been detected worldwide in Enterobacteriaceae and Pseudomonas aeruginosa isolates associated with transposon Tn4401 commonly located in plasmids. Acinetobacter baumannii has become an important multidrug-resistant nosocomial pathogen. KPC-producing A. baumannii has been reported to date only in Puerto Rico. The objective of this study was to determine the whole genomic sequence of a KPC-producing A. baumannii in order to (i) define its allelic diversity, (ii) identify the location and genetic environment of the blaKPC and (iii) detect additional mechanisms of antimicrobial resistance. Next-generation sequencing, Southern blot, PFGE, multilocus sequence typing and bioinformatics analysis were performed. The organism was assigned to the international ST2 clone. The blaKPC-2 was identified on a novel truncated version of Tn4401e (tentatively named Tn4401h), located in the chromosome within an IncA/C plasmid fragment derived from an Enterobacteriaceae, probably owing to insertion sequence IS26. A chromosomally located truncated Tn1 transposon harbouring a blaTEM-1 was found in a novel genetic environment within an antimicrobial resistance cluster. Additional resistance mechanisms included efflux pumps, non-ß-lactam antibiotic inactivating enzymes within and outside a resistance island, two class 1 integrons, In439 and the novel In1252, as well as mutations in the topoisomerase and DNA gyrase genes which confer resistance to quinolones. The presence of the blaKPC in an already globally disseminated A. baumannii ST2 presents a serious threat of further dissemination.

Characterization of Puerto Rican West Nile Virus isolates in mice.

BACKGROUND: West Nile virus (WNV) is a neurotropic arbovirus that was first isolated in 1937 in the West Nile District of Uganda. The virus emerged in New York in 1999 and is now endemic in North America (2007). The first virus isolates from Puerto Rico were obtained in 2007 from a chicken (PR20wh) and a mosquito pool (PR423). Our study further characterized these viral isolates using in vitro plaque morphology assays and in vivo using a Balb/c mice pathogenesis model. METHODS AND RESULTS: In the in vitro experiments, PR WNV isolates produced significantly smaller plaques in Vero cells compared to the New York 1999 strain (NY99). For the in vivo experiments, PR WNV isolates were propagated in mammalian (Vero) and insect (C6/36) cell lines and then inoculated in Balb/c mice. When WNV was propagated in Vero cells, we observed a trend towards significance in the survival rate with PR20wh compared to NY99 (log rank, p = 0.092). Regardless of whether the viral isolates were propagated in Vero or C6/36 cells, we found a significantly greater survival in mice infected with PR20wh strain, when compared to NY99 (log rank, p = 0.04), while no statistical difference was detected between PR423 and NY99 (p = 0.84). The average survival time (AST) in mice was significantly lower in C6/36-derived PR423 when compared to C6/36-derived NY99 (t-test, p = 0.013), and Vero-derived PR423 (t-test, p < 0.001). Eight days post infection in mice the viral load in brain tissue for Vero-derived PR423 was significantly higher when compared to NY99 and PR20wh. CONCLUSIONS: These results suggest that the PR WNV isolate, PR20wh, is a less pathogenic strain in mice than NY99. Moreover, we found that PR423 is a pathogenic isolate that causes faster mortality than NY99, when propagated in C6/36.

ISEcp1-mediated transposition of blaKPC into the chromosome of a clinical isolate of Acinetobacter baumannii from Puerto Rico.

Carbapenems are the last-resort antibiotics for the treatment of infections caused by multidrug-resistant Gram-negative bacilli. Klebsiella pneumoniae carbapenemase (KPC) hydrolyses ß-lactam antibiotics including the carbapenems. KPCs have been detected in Enterobacteriaceae and Pseudomonas aeruginosa isolates worldwide associated with transposon Tn4401 commonly located in plasmids. Acinetobacter baumannii has become an important multidrug-resistant nosocomial pathogen capable of hydrolysing the carbapenem antibiotics. KPC-producing A. baumannii has so far only been reported in Puerto Rico. During a surveillance study, four KPC-producing A. baumannii with identical pulse type were identified in a single institution. The objectives of this study were to characterize the KPC genetic background and the allelic diversity of one of the isolates. Next-generation sequencing and multilocus sequence typing (MLST) were performed. Molecular characterization of the isolate demonstrated blaKPC in Tn4401b located in the bacterial chromosome within a 26.5 kb DNA fragment, which included a KQ-like element (18.9 kb) very similar to that described previously in a K. pneumoniae plasmid and a 7.6 kb DNA fragment with 98 % homology to a putative plasmid from Yersinia pestis strain PY-95. Our data suggested that the 26.5 kb DNA fragment harbouring blaKPC was integrated in the chromosome by a transposition event mediated by the transposase of ISEcp1 found in the KQ-like element. MLST showed a novel sequence type, ST250. To our knowledge, this is the first report of the identification of the genetic background of blaKPC in A. baumannii.

Induction of neutralization antibodies in mice by Dengue-2 envelope DNA vaccines.

BACKGROUND: Dengue (DEN) viruses have become a public health problem that affects approximately 100 million people worldwide each year. Prevention measures rely on vector control programs, which are inefficient. Therefore, a vaccine is urgently needed. METHODS: The main goal of our laboratory is to develop an efficient tetravalent DEN DNA vaccine. In this study, we constructed four DEN-2 DNA vaccines expressing prM/env genes, using the homologous leader sequence (VecD2, VRD2E) or the tissue plasminogen activator (tPA) secretory signal (VecD2tpa, VRD2tpa). In vitro expression was tested by transient transfections and Western blot. The immunogenicity and protective efficacy of the vaccine candidates was evaluated in BALB/c mice, using intramuscular (IM) and intradermal (ID) vaccination routes. RESULTS: Envelope (E) protein expression was detected in transfected COS-7 or 293T cells. We found statistical differences in the antibody responses induced by these vaccine candidates. In addition, the strongest antibody responses and protection were observed when the vaccines were delivered intramuscularly. Moreover, the tPA leader sequence did not significantly improve the vaccine immunogenicity since VecD2 and VecD2tpa induced similar antibody responses. CONCLUSIONS: We demonstrated that most of our DNA vaccine candidates could induce antibody responses and partial protection against DEN-2 virus in mice. These results provide valuable information for the design and construction of a tetravalent DEN DNA vaccine.

Detection of rotavirus in stool samples of gastroenteritis patients.

In this pilot study, we examined 100 stool samples from patients with gastroenteritis to determine the presence of Rotavirus using immunoassays and molecular diagnostic methods. When the samples were analyzed by enzyme-linked immunoabsorbent assay (ELISA), we found 11 Rotavirus-positive samples. However, using molecular techniques (reverse transcriptase-polymerase chain reaction (RT/PCR), we identified 51 positive samples for Rotavirus. These results corroborate the generally accepted concept that molecular techniques are more sensitive than serological diagnostic tests. In addition, our data suggests that Rotavirus is an important etiologic agent of gastroenteritis in the local pediatric population. More extensive studies are necessary to determine the prevalence of Rotavirus in Puerto Rico in order to design effective control measures to protect our population against this pathogen.

The microbial etiologies of diarrhea in hospitalized patients from the Puerto Rico Medical Center Hospitals.

The development of diarrhea in hospitalized patients is a frequently encountered clinical problem, which may be due to infectious or non-infectious causes. The purpose of this study was to identify which common community enteric pathogens, if any, are responsible for diarrheal episodes in hospitalized patients. Stool samples from 76 consecutive, hospitalized patients were analyzed utilizing routine bacterial cultures, smears for identification of ova and parasites and Enzyme-Link Immunoadsorbent Assay (ELISA) for enteric bacteria, parasites and viruses. The results obtained demonstrated that the usual community enteric pathogens were not identified as a major cause of nosocomial diarrhea. In hospital-acquired diarrhea, Clostridium difficile toxins assay was the only clinically significant test in the evaluation of these patients. As a result of this study a guideline for the management of this condition in hospitalized patients is presented.