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Featured researches published by Guillermo Pimentel.


Eurosurveillance | 2006

Two clusters of human infection with influenza A/H5N1 virus in the Republic of Azerbaijan, February–March 2006

Andreas Gilsdorf; N Boxall; V Gasimov; I Agayev; F Mammadzade; P Ursu; E Gasimov; C Brown; S Mardel; D Jankovic; Guillermo Pimentel; I Amir Ayoub; E Maher Labib Elassal; C Salvi; Dominique Legros; C Pessoa da Silva; A Hay; R Andraghetti; G Rodier; B Ganter

Following the appearance of influenza A/H5 virus infection in several wild and domestic bird species in the Republic of Azerbaijan in February 2006, two clusters of potential human avian influenza due to A/H5N1 (HAI) cases were detected and reported by the Ministry of Health (MoH) to the World Health Organization (WHO) Regional Office for Europe during the first two weeks of March 2006. On 15 March 2006, WHO led an international team, including infection control, clinical management, epidemiology, laboratory, and communications experts, to support the MoH in investigation and response activities. As a result of active surveillance, 22 individuals, including six deaths, were evaluated for HAI and associated risk infections in six districts. The investigations revealed eight cases with influenza A/H5N1 virus infection confirmed by a WHO Collaborating Centre for Influenza and one probable case for which samples were not available. The cases were in two unrelated clusters in Salyan (seven laboratory confirmed cases, including four deaths) and Tarter districts (one confirmed case and one probable case, both fatal). Close contact with and de-feathering of infected wild swans was considered to be the most plausible source of exposure to influenza A/H5N1 virus in the Salyan cluster, although difficulties in eliciting information were encountered during the investigation, because of the illegality of some of the activities that might have led to the exposures (hunting and trading in wild birds and their products). These cases constitute the first outbreak worldwide where wild birds were the most likely source of influenza A/H5N1 virus infection in humans. The rapid mobilisation of resources to contain the spread of influenza A/H5 in the two districts was achieved through collaboration between the MoH, WHO and its international partners. Control activities were supported by the establishment of a field laboratory with real-time polymerase chain reaction (RT-PCR) capacity to detect influenza A/H5 virus. Daily door-to-door surveillance undertaken in the two affected districts made it unlikely that human cases of influenza A/H5N1 virus infection remained undetected.


American Journal of Infection Control | 2010

Surveillance of catheter-associated urinary tract infection in 4 intensive care units at Alexandria university hospitals in Egypt.

Maha Talaat; Soad Hafez; Tamer Saied; Reham Elfeky; Waleed El-Shoubary; Guillermo Pimentel

BACKGROUND We sought to measure the incidence rate of catheter-associated urinary tract infections (CAUTIs), identify risk factors associated with acquiring the infections; and identify the etiologic and antibiotic resistant patterns associated with CAUTIs in the intensive care units (ICUs) of a large University Hospital in Alexandria, Egypt. METHODS Prospective active surveillance of CAUTIs was conducted in 4 ICUs during a 13-month period from January 1, 2007 through January 31, 2008 in Alexandria University Hospital using the standard Centers for Disease Control National Nosocomial Infection Surveillance (NNIS) case definitions. Rates were expressed as the number of infections per 1000 catheter days. RESULTS During the study period, 757 patients were monitored after ICU admission, with either existing indwelling urinary catheters (239), or got catheters inserted after ICU admission (518), for a total duration of 16301 patient days, and 10260 patient catheter days. A total of 161 episodes of infection were diagnosed, for an overall rate of 15.7 CAUTIs per 1000 catheter days. Important risk factors associated with acquiring CAUTI were female gender (Relative risk (RR), 1.7; 95% confidence interval (CI); 1.7-4.3), and previous catheterization within the same hospital admission (RR, 1.6; 95% CI; 1.3-1.96). Patients admitted to the chest unit, patients =40 years, patients with prolonged duration of catheterization, prolonged hospital and ICU stay had a significantly higher risk of acquiring CAUTIs. Out of 195 patients who had their urine cultured, 188 pathogens were identified for 161 infected patients; 96 (51%) were Candida, 63 (33.5%) gram negatives, 29 (15.4%) gram positives. The prevalence of ESBL producers among K. pneumoniae and E. coli isolates was 56% (14/25) and 78.6% (11/14), respectively. CONCLUSION Despite infection control policies and procedures, CAUTI rates remain a significant problem in Alexandria University hospital. Using the identified risk factors, tailored intervention strategies are now being implemented to reduce the rates of CAUTIs in these 4 ICUs.


Journal of Clinical Microbiology | 2009

Comparison of two multiple-locus variable-number tandem-repeat analysis methods for molecular strain typing of human Brucella melitensis isolates from the Middle East

Rebekah V. Tiller; Barun K. De; Marie Boshra; Lynn Y. Huynh; Matthew N. Van Ert; David M. Wagner; John D. Klena; T. S. Mohsen; S. S. El-Shafie; Paul Keim; Alex R. Hoffmaster; Patricia P. Wilkins; Guillermo Pimentel

ABSTRACT Brucella species are highly monomorphic, with minimal genetic variation among species, hindering the development of reliable subtyping tools for epidemiologic and phylogenetic analyses. Our objective was to compare two distinct multiple-locus variable-number tandem-repeat analysis (MLVA) subtyping methods on a collection of 101 Brucella melitensis isolates from sporadic human cases of brucellosis in Egypt (n = 83), Qatar (n = 17), and Libya (n = 1). A gel-based MLVA technique, MLVA-15IGM, was compared to an automated capillary electrophoresis-based method, MLVA-15NAU, with each MLVA scheme examining a unique set of variable-number tandem repeats. Both the MLVAIGM and MLVANAU methods were highly discriminatory, resolving 99 and 101 distinct genotypes, respectively, and were able to largely separate genotypes from Egypt and Qatar. The MLVA-15NAU scheme presented higher strain-to-strain diversity in our test population than that observed with the MLVA-15IGM assay. Both schemes were able to genetically correlate some strains originating from the same hospital or region within a country. In addition to comparing the genotyping abilities of these two schemes, we also compared the usability, limitations, and advantages of the two MLVA systems and their applications in the epidemiological genotyping of human B. melitensis strains.


Antimicrobial Agents and Chemotherapy | 2008

Antimicrobial Susceptibilities of Geographically Diverse Clinical Human Isolates of Leptospira

Roseanne A. Ressner; Matthew E. Griffith; Miriam L. Beckius; Guillermo Pimentel; R. Scott Miller; Katrin Mende; Susan Fraser; Renee L. Galloway; Duane R. Hospenthal; Clinton K. Murray

ABSTRACT Although antimicrobial therapy of leptospirosis has been studied in a few randomized controlled clinical studies, those studies were limited to specific regions of the world and few have characterized infecting strains. A broth microdilution technique for the assessment of antibiotic susceptibility has been developed at Brooke Army Medical Center. In the present study, we assessed the susceptibilities of 13 Leptospira isolates (including recent clinical isolates) from Egypt, Thailand, Nicaragua, and Hawaii to 13 antimicrobial agents. Ampicillin, cefepime, azithromycin, and clarithromycin were found to have MICs below the lower limit of detection (0.016 μg/ml). Cefotaxime, ceftriaxone, imipenem-cilastatin, penicillin G, moxifloxacin, ciprofloxacin, and levofloxacin had MIC90s between 0.030 and 0.125 μg/ml. Doxycycline and tetracycline had the highest MIC90s: 2 and 4 μg/ml, respectively. Doxycycline and tetracycline were noted to have slightly higher MICs against isolates from Egypt than against strains from Thailand or Hawaii; otherwise, the susceptibility patterns were similar. There appears to be possible variability in susceptibility to some antimicrobial agents among strains, suggesting that more extensive testing to look for geographic variability should be pursued.


Emerging Infectious Diseases | 2013

Microevolution of highly pathogenic avian influenza A(H5N1) viruses isolated from humans, Egypt, 2007-2011.

Mary Younan; Mee Kian Poh; Emad Elassal; Todd Davis; Pierre Rivailler; Amanda Balish; Natosha Simpson; Joyce Jones; Varough Deyde; Rosette Loughlin; Ije Perry; Larisa V. Gubareva; Maha A. Elbadry; Shaun Truelove; Anne M. Gaynor; Emad Mohareb; Magdy A. Amin; Claire Cornelius; Guillermo Pimentel; Kenneth C. Earhart; Amel Naguib; Ahmed S. Abdelghani; Samir Refaey; Alexander Klimov; Ruben O. Donis; Amr Kandeel

We analyzed highly pathogenic avian influenza A(H5N1) viruses isolated from humans infected in Egypt during 2007–2011. All analyzed viruses evolved from the lineage of subtype H5N1 viruses introduced into Egypt in 2006; we found minimal evidence of reassortment and no exotic introductions. The hemagglutinin genes of the viruses from 2011 formed a monophyletic group within clade 2.2.1 that also included human viruses from 2009 and 2010 and contemporary viruses from poultry; this finding is consistent with zoonotic transmission. Although molecular markers suggestive of decreased susceptibility to antiviral drugs were detected sporadically in the neuraminidase and matrix 2 proteins, functional neuraminidase inhibition assays did not identify resistant viruses. No other mutations suggesting a change in the threat to public health were detected in the viral proteomes. However, a comparison of representative subtype H5N1 viruses from 2011 with older subtype H5N1 viruses from Egypt revealed substantial antigenic drift.


American Journal of Tropical Medicine and Hygiene | 2011

Cross-Species Surveillance of Leptospira in Domestic and Peri-Domestic Animals in Mahalla City, Gharbeya Governorate, Egypt

Stephen A. Felt; Momtaz O. Wasfy; Wael F. El-Tras; Ahmed Samir; Bassem Abdel Rahaman; Marie Boshra; Tina M. Parker; Mahmoud Essam Hatem; Ahmed Ahmed El-Bassiouny; Clinton K. Murray; Guillermo Pimentel

A survey of 179 animals (black rats, dogs, sheep, buffaloes, cattle, donkeys, weasels, and cats) for Leptospira infection was conducted in Mahalla City (Lower Egypt). Blood, urine, and kidney were collected and tested by culture, microscopic agglutination test (MAT), and/or polymerase chain reaction (PCR). Among rats, 26% were positive by PCR, including 7% that were also positive by culture for L. interrogans serovars Grippotyphosa, Pyrogenes, and Icterohaemorrhagiae. L. borpetersenii serovar Polonica was isolated for the first time in Egypt in three rats. MAT titers ≥ 1:800 were observed in 11% of rats and 12% of dogs. L. interrogans serovar Grippotyphosa was detected in one cat. Sheep and donkeys were negative for leptospirosis by all methods. Buffaloes and cattle were seropositive in 20% and 44% of animals, respectively. Data indicate that several pathogenic serovars are circulating in the animals, which may pose exposure risks and account for high rates of acute febrile illness.


American Journal of Infection Control | 2011

Antimicrobial resistance in pathogens causing nosocomial bloodstream infections in university hospitals in Egypt

Tamer Saied; Amany El-Kholy; Soad Hafez; Hadia Basim; Momtaz O. Wasfy; Waleed El-Shoubary; Ahmed Samir; Guillermo Pimentel; Maha Talaat

BACKGROUND Nosocomial bloodstream infections (BSIs) and antimicrobial resistance (AMR) are worldwide health care problems causing substantial patient morbidity and mortality. This study was conducted to identify bacterial pathogens isolated from nosocomial BSIs and determine their AMR patterns. METHODS An active surveillance program for BSIs was conducted in intensive care units in 3 large university hospitals in Egypt between September 1, 2006, and June 30, 2007. Infection prevention and control teams and link nurses in collaboration with intensive care physicians were looking actively to identify patients who acquired BSIs based on Centers for Disease Control and Prevention standard case definitions. Blood cultures were obtained from patients with suspected BSIs and processed to isolate bacteria and test their antimicrobial resistance. RESULTS During the 10-month active surveillance period, a total of 600 pathogens were isolated from blood cultures of 1,575 patients (38%). Of these 600 isolates, 386 (66%) were gram-negative, 178 (30%) were gram-positive, and 24 (4%) were budding yeasts. The gram-negative organisms included 162 (27%) Klebsiella pneumoniae and 23 (3.8%) Escherichia coli. Extended-spectrum β-lactamase enzymes were detected in 79% of the K pneumoniae isolates and 39% of the E coli isolates. Methicillin-resistant Staphylococcus aureus accounted for 60% of S aureus infections. CONCLUSIONS High rates of β-lactamase resistance and methicillin-resistant S aureus were found in the 3 Egyptian university hospitals studied. This study highlights the need for strengthening infection prevention and control programs, monitoring AMR at each facility, and developing policies for antibiotic use.


American Journal of Tropical Medicine and Hygiene | 2011

Challenges of Establishing the Correct Diagnosis of Outbreaks of Acute Febrile Illnesses in Africa: The Case of a Likely Brucella Outbreak among Nomadic Pastoralists, Northeast Kenya, March–July 2005

Mary D. Ari; Argata Guracha; Moustafa Abdel Fadeel; Charles Njuguna; M. Kariuki Njenga; Rosalia Kalani; Hassan Abdi; Osman Warfu; Victor Omballa; Christopher Tetteh; Robert F. Breiman; Guillermo Pimentel; Daniel R. Feikin

An outbreak of acute febrile illness was reported among Somali pastoralists in remote, arid Northeast Kenya, where drinking raw milk is common. Blood specimens from 12 patients, collected mostly in the late convalescent phase, were tested for viral, bacterial, and parasitic pathogens. All were negative for viral and typhoid serology. Nine patients had Brucella antibodies present by at least one of the tests, four of whom had evidence suggestive of acute infection by the reference serologic microscopic agglutination test. Three patients were positive for leptospiral antibody by immunoglobulin M enzyme-linked immunosorbent assay, and two were positive for malaria. Although sensitive and specific point-of-care testing methods will improve diagnosis of acute febrile illness in developing countries, challenges of interpretation still remain when the outbreaks are remote, specimens collected too late, and positive results for multiple diseases are obtained. Better diagnostics and tools that can decipher overlapping signs and symptoms in such settings are needed.


Annals of Clinical Microbiology and Antimicrobials | 2012

In vitro antibiotic susceptibility testing of Brucella isolates from Egypt between 1999 and 2007 and evidence of probable rifampin resistance

Mohamed Abdel-Maksoud; Brent House; Momtaz O. Wasfy; Bassem Abdel-Rahman; Guillermo Pimentel; Gehan Roushdy; Erica Dueger

BackgroundBrucellosis poses a significant public health problem in Mediterranean countries, including Egypt. Treatment of this disease is often empirical due to limited information on the antibiotic susceptibility profiles of Brucella spp. in this region of the world. The aim of this study was to determine the antibiotic susceptibility profiles of Brucella blood isolates in Egypt, a country endemic for brucellosis.MethodsBrucella spp. isolates were identified from the blood cultures of acute febrile illness (AFI) patients presenting to a network of infectious disease hospitals from 1999–2007. Minimum inhibitory concentrations were determined for tetracycline, gentamicin, doxycycline, trimethoprim-sulfamethoxazole, streptomycin, ceftriaxone, ciprofloxacin and rifampin using the E-test. Interpretations were made according to Clinical and Laboratory Standards Institute (CLSI) guidelines.ResultsA total of 355 Brucella spp. isolates were analyzed. All were susceptible to tetracycline, doxycycline, trimethoprim-sulfamethoxazole, streptomycin and ciprofloxacin; probable resistance to rifampin and ceftriaxone was observed among 277 (64%) and 7 (2%) of the isolates, respectively. Percentages of isolates showing probable resistance to rifampin were significantly lower before 2001 than in the following years (7% vs. >81%, p < 0.01).ConclusionsDespite the high burden of brucellosis in Egypt and frequent empirical treatment, isolates have remained susceptible to the majority of tested antibiotics. However, this is the first report of high rates of probable resistance to rifampin among Brucella isolates from Egypt. Patients should be closely monitored while following standard treatment regimens. Continued surveillance, drug susceptibility studies and updated CLSI interpretive criteria are needed to monitor and update antibiotic prescribing policies for brucellosis.


Transactions of The Royal Society of Tropical Medicine and Hygiene | 2011

Use of patient-specific Leptospira isolates in the diagnosis of leptospirosis employing microscopic agglutination testing (MAT)

Clinton K. Murray; Michael R. Gray; Katrin Mende; Tina M. Parker; Ahmed Samir; Bassem Abdel Rahman; Engy Emil Habashy; Duane R. Hospenthal; Guillermo Pimentel

Given the protean manifestations of leptospirosis, adequate laboratory support for diagnosis is necessary. Traditionally, the gold standard is the microscopic agglutination test (MAT) using a panel of Leptospira isolates representing a broad range of serogroups and serovars. It has been proposed that screening with serovars circulating in a region would enhance test performance. We assessed the diagnostic usefulness of MAT using both regionally obtained clinical Leptospira isolates and the specific isolates recovered from the tested patients. Serum obtained from 41 acute febrile patients (obtained on average 7.2 days [SD±5.2] after onset of fever) was tested using a standard panel of 24 serovars along with regional isolates recovered from human and animal blood cultures from different regions in Egypt and a patients own isolate, if available, to establish additional MAT panels. Serum samples tested by a standard 24 panel with a cut-off of >1:800 revealed five patients with positive serology. Only one patient had a positive result using a regional panel or patients own culture developed MAT. However, the serovar with the highest titers did not match the cultured serovar. Region-specific MATs did not appear to be reliable in detection of infection or in identifying the infecting serovar.

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Dive into the Guillermo Pimentel's collaboration.

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John D. Klena

Centers for Disease Control and Prevention

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Moustafa Abdel Fadeel

Centers for Disease Control and Prevention

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Clinton K. Murray

San Antonio Military Medical Center

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Brent House

Walter Reed Army Institute of Research

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Erica Dueger

National Center for Immunization and Respiratory Diseases

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Matthew J. Hepburn

United States Army Medical Research Institute of Infectious Diseases

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Christian T. Bautista

Naval Medical Research Center

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