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Featured researches published by Benjamin Espinosa.


Antimicrobial Agents and Chemotherapy | 2011

Antimicrobial Susceptibility of Brucella melitensis Isolates in Peru

Ryan C. Maves; Rosa Castillo; Alfredo Guillén; Benjamin Espinosa; Rina Meza; Nereyda Espinoza; Gladys Nunez; Luis Sánchez; Jesús Chacaltana; David Cepeda; Sofía González; Eric R. Hall

ABSTRACT Brucellosis is an important public health problem in Peru. We evaluated 48 human Brucella melitensis biotype 1 strains from Peru between 2000 and 2006. MICs of isolates to doxycycline, azithromycin, gentamicin, rifampin, ciprofloxacin, and trimethoprim-sulfamethoxazole were determined by the Etest method. All isolates were sensitive to tested drugs during the periods of testing. Relapses did not appear to be related to drug resistance.


Transactions of The Royal Society of Tropical Medicine and Hygiene | 2009

MLVA genotyping of human Brucella isolates from Peru

Henk L. Smits; Benjamin Espinosa; Rosa Castillo; Eric R. Hall; Alfredo Guillén; Milagros Zevaleta; Robert H. Gilman; Paolo Meléndez; Carlos Guerra; Angelika Draeger; Alessandro Broglia; Karsten Nöckler

Recent human Brucella melitensis isolates from Peru were genotyped by multiple locus variable number repeat analysis. All 24 isolates originated from hospitalized patients living in the central part of Peru and consisted of six genomic groups comprising two to four isolates and nine unique genotypes. The isolates were most closely related to the two previously genotyped isolates from Mexico, with a maximum distance of 2 to 4. The Peruvian strains were clearly distinct from the East and West Mediterranean groups of B. melitensis genotypes, suggesting that they may constitute a unique Latin American cluster.


Journal of Clinical Microbiology | 2009

Molecular Epidemiology of Brucella Genotypes in Patients at a Major Hospital in Central Peru

Karsten Nöckler; Ryan C. Maves; David Cepeda; Angelika Draeger; Anne Mayer-Scholl; Jesús Chacaltana; María Castañeda; Benjamin Espinosa; Rosa Castillo; Eric R. Hall; Sascha Al Dahouk; Robert H. Gilman; Franco Cabeza; Henk L. Smits

ABSTRACT The multiple-locus variable-number repeat analysis of 90 human Brucella melitensis isolates from a large urban area in central Peru revealed variations at 4 (Bruce07, Bruce09, Bruce18, and Bruce42) out of 16 loci investigated, of which 1 (Bruce42) also is used for species identification. Ten genotypes were identified, separated by the number of Bruce42 repeats into two groups that may have distinct phenotypic characteristics. Whereas genotypes with five or six Bruce42 repeats were cultured mainly from adult patients, genotypes with three Bruce42 repeats were isolated from children and young adolescents as well as from adults. In addition, the isolates with three Bruce42 repeats were obtained more often from patients with splenomegaly (P = 0.02) or hepatomegaly (P = 0.006). An annual variation in the diversity of genotypes was observed, possibly reflecting changes in sources of fresh dairy products, supply routes to city shops and markets, and the movement of infected dairy goat herds.


Vaccine | 2009

Susceptibility of the Aotus nancymaae owl monkey to eastern equine encephalitis

Benjamin Espinosa; Scott C. Weaver; Slobodan Paessler; Douglas Brining; Milagros Salazar; Tadeusz J. Kochel

Eastern equine encephalitis virus (EEEV) is an arthropod-borne virus associated with life-threatening encephalitis in humans, equines, birds and many other domestic animals. To investigate the suitability of the Aotus nancymaae New World owl monkey as a viable animal model for EEE candidate vaccine testing we used clinical presentation, serology, viral isolation and PCR to evaluate pathogenesis and immunity in infected animals. Monkeys were inoculated subcutaneously (SQ) or intranasally (IN) with 10(4)pfu of virulent EEEV and were initially followed for 45 days. While none of the animals displayed clinical signs of disease, all of the SC inoculated animals (n=6) manifested a viremia averaging 3.2 days (+/-0.8 days). Likewise, serologic responses (IgM, IgG and PRNT) were observed in all SC infected animals. Interestingly, none of the IN inoculated animals (n=6) became viremic or mounted an antibody response and no pathological abnormalities were observed in two animals that were necropsied on day 6 post-infection (p.i.) from each group. To determine if the antibodies produced by the SC inoculated animals were protective against homologous challenge, three animals from the SC group were serologically evaluated on day 253 p.i. and were administered an inoculum identical to initial challenge on day 270 p.i. A positive control group of four naïve animals was also infected as before. All of the naïve positive control animals manifested a similar viremia as observed initially, averaging 2.75 days (+/-0.5 days) while none of the previously challenged animals became viremic. On days 45 and 253 p.i. geometric mean PRNT titers in the SC group were 453 and 101, respectively. This study demonstrates that the Aotus nancymaae can be reproducibly infected with EEE virus and can serve as a suitable model for infection and immunogenicity for the evaluation of candidate vaccines against EEEV.


International Journal of Std & Aids | 2007

Facilitating lymphogranuloma venereum surveillance with the use of real time polymerase chain reaction.

Mark J. Siedner; Mark Pandori; Segundo R. Leon; Benjamin Espinosa; Eric R. Hall; Carlos F. Caceres; Thomas J. Coates; Jeffrey D. Klausner

questioned were willing to discuss HPV vaccination with both parents and children, with a further 18% (14 in total) prepared to talk to parents but not children. This group identified the same limiting factors as the teachers, again with no objections on religious grounds. Concerns raised by teachers and health-care professionals included insufficient knowledge about long-term efficacy of vaccination and a potential reduction in precautions taken to prevent STIs. All participants were asked what they felt was the best way to prevent STIs. Sexual health education emphasizing the use of barrier methods of contraception was considered most effective, but 60% (27) of patients, 71% (12) of primary care workers and 78% (10) of teachers recommended the addition of vaccination strategies to education programmes. Our results indicate that while knowledge about the vaccines among health-care professionals appears good, the other groups we surveyed are poorly informed, despite recent media coverage. This situation must be further assessed, as we have demonstrated that explanation about the risks of HPV infection and the benefits of immunization can potentially result in high levels of vaccine uptake. We found little opposition to the inclusion of non-oncogenic strains of HPV in vaccines among any of our study groups. Attitudes towards vaccination among patients previously diagnosed with an STI did not differ significantly to those of individuals with no history of infection. Education of parents, children and the public at large is paramount to achieving a successful vaccination programme, and this responsibility rests with a multidisciplinary workforce, consisting of doctors, nurses and health visitors, those working for sexual health promotion organizations and teachers, with the support of the government and the media. This study was an extension of an undergraduate assignment completed for the School of Medical Education, University of Liverpool, UK


Journal of Travel Medicine | 2010

The Effect of Preparation of Cebiche on the Survival of Enterotoxigenic Escherichia coli, Aeromonas hydrophila, and Vibrio parahaemolyticus

Andrés Herrera; Benjamin Espinosa; Gladys Nunez; Nereyda Espinoza; Ryan C. Maves; Gregory J. Martin

BACKGROUND Cebiche is a common dish in Latin America, prepared using raw fish mixed with vegetables and marinated with lime juice. The acidity of the lime juice is commonly believed to destroy bacteria and render cebiche as safe to eat. Little data exist concerning rates of cebiche-associated gastroenteritis outbreaks, although these may be high given the popularity of the dish. METHODS We inoculated raw fish with Aeromonas hydrophila, Vibrio parahaemolyticus, and enterotoxigenic Escherichia coli to determine the effect of the cebiche preparation process on bacterial viability. Raw fish were exposed to a suspension of 1.0 × 10(8) colony-forming units (CFUs) of each organism in a 50-mL solution, prior to the addition of cebiche ingredients. A typical Peruvian cebiche recipe was used combining limes, onions, sweet potatoes, cilantro, and hot peppers marinated together for 30 minutes. A homogenized mixture of the dish was then evaluated for pH and bacterial counts at 0, 10, and 30 minutes. As much as 100 µL of inocula were streaked onto tryptic soy agar (TSA) agar plates and incubated for 24 hours. RESULTS The initial average pH of the fish was 6.4 prior to adding cebiche ingredients and 5.0 immediately afterwards. The pH at 10- and 30-minute periods was 5.4 and 5.2, respectively. Little reduction in bacterial counts was observed at either the 10- or 30-minute time periods, with counts increasing at 30 minutes. CONCLUSIONS The putative bactericidal role of lime juice in the preparation process is not sufficient to reduce the microbial population present in cebiche. Pathogens may remain viable after exposure to acidic conditions. The increasing popularity of Peruvian cuisine may also lead to cebiche-associated illness outside of Latin America.


Military Medicine | 2013

Expanded Sexually Transmitted Infection Surveillance Efforts in the United States Military: A Time for Action

Jose L. Sanchez; Brian K. Agan; Alice Y. Tsai; Grace E. Macalino; Eyako Wurapa; Margaret Mbuchi; Erica Dueger; Katherine C. Horton; Silvia M. Montano-Torres; Drake H. Tilley; Karen Saylors; Naiki Puplampu; Christopher Duplessis; Dustin J. Harrison; Shannon D. Putnam; Eric C. Garges; Benjamin Espinosa; Jamal Dejli; Mitchell Meyers; Samuel L. Yingst; Ann E. Jerse; Hala H. Maktabi; Ronald L. Burke; Nikki N. Jordan; Gosia Nowak; Katherine Hsu; O. O. Soge; King K. Holmes; R. Scott McClelland; Michael R. Macdonald

COL Jose L. Sanchez, MC USA (Ret.)*†; Brian K. Agan, MD‡; Alice Y. Tsai, MPH*; Grace E. Macalino, PhD‡; LTC Eyako Wurapa, MC USA§; Margaret Mbuchi, PhD§; Erica Dueger, DVM, PhD∥; Katherine C. Horton, MPH∥; Silvia M. Montano-Torres, MD, MPH¶; LCDR Drake H. Tilley, MC USN¶; Karen E. Saylors, PhD**; Naiki Puplampu, MPhil, PhD††; LCDR Christopher C. Duplessis, MC USN††; LCDR Dustin J. Harrison, MSC USN‡‡; CDR Shannon D. Putnam, MSC USN (Ret.)§§; MAJ Eric C. Garges, MC USA∥∥; LCDR Benjamin J. Espinosa, MSC USN¶¶; LCDR Jamal Dejli, MSC USN***; COL Mitchell Meyers, MC USA†††; LTC Samuel L. Yingst, VC USA†††; Ann E. Jerse, PhD‡‡‡; Hala H. Maktabi, PhD, MPH*; MAJ Ronald L. Burke, VC USA*; Nikki N. Jordan, MPH§§§; Gosia Nowak, MSc, MPH∥∥∥; Katherine Hsu, MD, MPH¶¶¶; Olusegun O. Soge, PhD****††††; King K. Holmes, MD, PhD****††††; R. Scott McClelland, MD, MPH****††††; Michael R. MacDonald, MS‡‡‡‡; COL Julie A. Pavlin, MC USA (Ret.)†; COL Joel C. Gaydos, MC USA (Ret.)*†; COL Edmund C. Tramont, MC USA (Ret.)§§§§


BMC Infectious Diseases | 2013

Detection of human leptospirosis as a cause of acute fever by capture ELISA using a Leptospira interrogans serovar Copenhageni (M20) derived antigen

Enrique Canal; Simon Pollett; Kristen Heitzinger; Michael Gregory; Matthew R. Kasper; Eric S. Halsey; Yocelinda Meza; Kalina Campos; Juan Antonio Galbis Pérez; Rina Meza; Maruja Bernal; Alfredo Guillén; Tadeusz J. Kochel; Benjamin Espinosa; Eric R. Hall; Ryan C. Maves

BackgroundLeptospirosis is a potentially lethal zoonosis mainly affecting low-resource tropical countries, including Peru and its neighbouring countries. Timely diagnosis of leptospirosis is critical but may be challenging in the regions where it is most prevalent. The serodiagnostic gold standard microagglutination test (MAT) may be technically prohibitive. Our objective in this study was to assess the sensitivity, specificity, and predictive value of an IgM antibody capture enzyme-linked immunoassay (MAC-ELISA) derived from the M20 strain of Leptospira interrogans serovar Copenhageni (M20) by comparison to MAT, which was used as the gold standard method of diagnosis.MethodsAcute and convalescent sera from participants participating in a passive febrile surveillance study in multiple regions of Peru were tested by both IgM MAC-ELISA and MAT. The sensitivity, specificity, positive and negative predictive value (PPV, NPV) of the MAC-ELISA assay for acute, convalescent and paired sera by comparison to MAT were calculated.ResultsThe sensitivity, specificity, PPV and NPV of the MAC-ELISA assay for acute sera were 92.3%, 56.0%, 35.3% and 96.6% respectively. For convalescent sera, the sensitivity, specificity, PPV and NPV of the MAC-ELISA assay were 93.3%, 51.5%, 63.6% and 89.5% respectively. For paired sera, the sensitivity, specificity, PPV and NPV of the MAC-ELISA assay were 93.6%, 37.5%, 59.2%, 85.7% respectively.ConclusionsThe M20 MAC-ELISA assay performed with a high sensitivity and low specificity in the acute phase of illness. Sensitivity was similar as compared with MAT in the convalescent phase and specificity remained low. Paired sera were the most sensitive but least specific by comparison to MAT serodiagnosis. NPV for acute, convalescent and paired sera was high. The limited specificity and high sensitivity of the MAC-ELISA IgM suggests that it would be most valuable to exclude leptospirosis in low-resource regions that lack immediate access to definitive reference laboratory techniques such as MAT.


International Journal of Std & Aids | 2008

Absence of lymphogranuloma venereum infection among high-risk men who have sex with men in Lima, Peru

Jesse L. Clark; Benjamin Espinosa; Segundo R. Leon; Eric R. Hall; Hector J Salvatierra; Carlos F. Caceres; Jeffrey D. Klausner; Thomas J. Coates

from Ten Case Studies. Washington DC: The World Bank, 2001 33 White OC, Bhatia A. Privatization in Africa. Washington DC: The World Bank, 1998 34 Hunter M. The changing political economy of sex in South Africa: the significance of unemployment and inequalities to the scale of the AIDS pandemic. Soc Sci Med 2007;64:689–700 35 Haworth A, Acuda W. Sub-Saharan Africa. In: Grant M ed. Alcohol and Emerging Markets. Washington: International Center for Alcohol Policies, 1998 36 Kortteinen T. Alcohol and urbanization in Africa. NAD Publication 1990;18:36–58 37 Houssou C, Bailly D, Parquet PJ. Tobacco, alcohol and advertising in west Africa. Annales de Psychiatrie 1999;14:227–31 38 Jernigan D. Country profile on alcohol in Zimbabwe. In: Marshall M, Riley L eds. Alcohol and Public Health in Eight Developing Countries. Geneva: WHO, 1999 39 McBride R, Mosher JF. Public health implications of the international alcohol industry: issues raised by a World Health Organisation project. Br J Addict 1985;80:141–7 40 Nyamukapa CA, Gregson S, Lopman B, et al. HIV-associated orphanhood and children’s psychosocial distress: theoretical framework tested with data from Zimbabwe. Am J Public Health 2008;98:133–41 41 Operario D, Pettifor A, Cluver L, MacPhail C, Rees H. Prevalence of parental death among young people in South Africa and risk for HIV infection. J Acquir Immune Defic Syndr 2007;44:93–8 42 Thurman TR, Brown L, Richter L, Maharaj P, Magnani R. Sexual risk behavior among South African adolescents: is orphan status a factor? AIDS Behav 2006;10:627–35 43 Sandoy IF, Siziya S, Fylkesnes K. Lost opportunities in HIV prevention: programmes miss places where exposures are highest. BMC Public Health 2008;8:31 [Epub ahead of print] 44 Weir SS, Morroni C, Coetzee N, Spencer J, Boerma JT. A pilot study of a rapid assessment method to identify places for AIDS prevention in Cape Town, South Africa. Sex Transm Infect 2002;78:i106–13 45 Kapiga SH, Sam NE, Shao JF, et al. HIV-1 epidemic among female bar and hotel workers in northern Tanzania: risk factors and opportunities for prevention. J Acquir Immune Defic Syndr 2002;29:409–17 46 Van Blerk L. AIDS, mobility and commercial sex in Ethiopia: implications for policy. AIDS Care 2007;19:79–86 47 Ao TT, Sam NE, Masenga EJ, Seage GR 3rd, Kapiga SH. Human immunodeficiency virus type 1 among bar and hotel workers in northern Tanzania: the role of alcohol, sexual behavior, and herpes simplex virus type 2. Sex Transm Dis 2006;33:163–9 48 Kalichman SC, Simbayi LC, Vermaak R, Jooste S, Cain D. HIV/AIDS risks among men and women who drink at informal alcohol serving establishments (Shebeens) in Cape Town, South Africa. Prev Sci 2008;[Epub ahead of print] 49 Luginaah I. Local gin (akpeteshie) and HIV/AIDS in the Upper West Region of Ghana: The need for preventive health policy. Health Place. 2008;[Epub ahead of print] 50 Ferguson AG, Morris CN. Mapping transactional sex on the Northern Corridor highway in Kenya. Health Place 2007;13:504–19 51 Lewis JJ, Garnett GP, Mhlanga S, Nyamukapa CA, Donnelly CA, Gregson S. Beer halls as a focus for HIV prevention activities in rural Zimbabwe. Sex Transm Dis 2005;32:364–9 52 Weir SS, Pailman C, Mahlalela X, Coetzee N, Meidany F, Boerma JT. From people to places: focusing AIDS prevention efforts where it matters most. AIDS 2003;17:895–903


American Journal of Tropical Medicine and Hygiene | 2007

Evaluation of brucellosis by PCR and persistence after treatment in patients returning to the hospital for follow-up

Kathlène S. J. S. M. Maas; Melissa Mendez; Milagros Zavaleta; Jennie Manrique; María Pía Franco; Maximilian Mulder; Nilo Bonifacio; María Castañeda; Jesús Chacaltana; Elena Yagui; Robert H. Gilman; Alfredo Guillén; David L. Blazes; Benjamin Espinosa; Eric R. Hall; Theresia H. Abdoel; Henk L. Smits

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Eric R. Hall

Naval Medical Research Center

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Jesús Chacaltana

Naval Medical Research Center

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Ryan C. Maves

Naval Medical Research Center

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Alfredo Guillén

Universidad Nacional Federico Villarreal

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Henk L. Smits

Royal Tropical Institute

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Rosa Castillo

Naval Medical Research Center

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David Cepeda

Naval Medical Research Center

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Gladys Nunez

Naval Medical Research Center

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