Publications by authors named "Humberto Guerra"

In 2017, a major outbreak of Zika virus (ZIKV) infection took place in Chincha Province, Peru, where arboviral circulation had never been reported before. We conducted a cross-sectional survey (March-May 2019) in two districts of Chincha Province: Pueblo Nuevo and Chincha Baja. We included residents who were 20 to 40 years old and who had lived in these districts for at least 1 year.

View Article and Find Full Text PDF

The type III secretion system of Pseudomonas aeruginosa is an important virulence factor contributing to the cytotoxicity and the invasion process of this microorganism. The current study aimed to determine the presence of the exoU+/exoS+ genotype in P. aeruginosa clinical isolates.

View Article and Find Full Text PDF

Infections with Bartonella bacilliformis result in Carrion's disease in humans. In the first phase of infection, the pathogen causes a hemolytic fever ("Oroya fever") with case-fatality rates as high as ~90% in untreated patients, followed by a chronical phase resulting in angiogenic skin lesions ("verruga peruana"). Bartonella bacilliformis is endemic to South American Andean valleys and is transmitted via sand flies (Lutzomyia spp.

View Article and Find Full Text PDF

The relationships between specific type IV pili (TFP) groups and antibiotic resistance, biofilm formation, and bacterial motility were determined in 190 Pseudomonas aeruginosa clinical isolates. While motility and biofilm formation were determined by phenotypic assays, the presence of TFP was determined by PCR assay and antibiotic susceptibility by disk diffusion. The results showed a high ability to form biofilm (97.

View Article and Find Full Text PDF

Introduction: The salmonelloses are among the commonest, most widespread human zoonotic infections. They have generated international networks to attempt their control, since they cause a spectrum of ailments, ranging from inapparent carrier states to full-blown, severe, sometimes deadly diarrheal and systemic disease. Rapid diagnosis is needed for a number of reasons.

View Article and Find Full Text PDF

MexAB-OprM and MexEF-OprN are Pseudomonas aeruginosa efflux pumps involved in the development of antibiotic resistance. Several studies developed with laboratory strains or using a few clinical isolates have reported that the regulation system of MexEF-OprN is involved in the final levels of MexAB-OprM expression. Therefore, this study was aimed to determine the interplay between MexAB-OprM and MexEF-OprN in 90 out of 190 P.

View Article and Find Full Text PDF

Balamuthia mandrillaris is an opportunistic free-living amoeba that has been reported to cause skin lesions and the fatal Balamuthia amoebic encephalitis (BAE) in humans and other animals. Currently, around 200 human BAE cases have been reported worldwide, although this number is considered to be underestimated. The highest number of BAE cases has been reported in the American continent, mainly in the southwest of the USA.

View Article and Find Full Text PDF

Objectives: To assess the bacteriophage activity in localized and systemic infections caused by Staphylococcus aureus resistant to methicilin (MRSA).

Materials And Methods: An experimental study was performed in 45 mice of the Balb/c strain divided in nine groups of five individuals. Ten naive bacteriophages were isolated through clinical samples and hospital effluents.

View Article and Find Full Text PDF

Background: Pediculosis capitis is a ubiquitous parasitic skin disease associated with intense pruritus of the scalp. In developing countries it frequently affects children and adults, but epidemiological data at the community level are rare.

Objectives: To assess prevalence and risk factors associated with pediculosis capitis in a resource-poor community in Lima, Peru.

View Article and Find Full Text PDF

Objectives: To determine the pattern of antibiotic susceptibility of isolated Streptococcus pneumoniae strains of healthy nasopharyngeal carriers younger than 2 years in seven regions of Peru.

Materials And Methods: Between 2007 and 2009, nasopharyngeal swab samples were collected among 2123 healthy children aged 2-24 months in growth and development medical practices (CRED) and vaccination offices of hospitals and health centers in Lima, Piura, Cusco, Abancay, Arequipa, Huancayo, and Iquitos. The resistance to ten antibiotics through disk diffusion sensitivity testing of isolated pneumococcus strains was determined.

View Article and Find Full Text PDF

Free Living Amoebae (FLA) of Acanthamoeba genus are widely distributed in the environment and can be found in the air, soil and water; and have also been isolated from air-conditioning units. In humans, they are causative agents of a sight-threating infection of the cornea, Acanthamoeba keratitis (AK) and a fatal infection of the central nervous system known as Granulomatous Amoebic Encephalitis (GAE). In this study, a survey was conducted in order to determine the presence and pathogenic potential of free-living amoebae of Acanthamoeba genus in nasal swabs from individuals in two regions of Peru.

View Article and Find Full Text PDF

Brucella melitensis is highly infectious for humans and can be transmitted to humans in a number of epidemiological contexts. Within the context of an ongoing brucellosis surveillance project, an outbreak at a Peruvian police officer cafeteria was discovered, which led to active surveillance (serology, blood culture) for additional cases among 49 police officers who had also eaten there. The cohort was followed up to 18 months regardless of treatment or symptoms.

View Article and Find Full Text PDF

Developing countries suffer from brain drain for many decades. Industrialized countries have raised their barriers against immigrants, but have created mechanisms to attract foreign professionals, with aggressive policies to capture talents, in an effort to increase their competitiveness. To mitigate the effects of the migration of scientists, the Universidad Peruana Cayetano Heredia has created its own "return scholarship" about 12 years ago, and has repatriated 12 scientists through it.

View Article and Find Full Text PDF

Bartonella spp are fastidious bacteria that occur in the blood of man and mammals; they are usually vector borne but can also be transmitted by animal scratches and bites. The bartonelloses of medical importance comprise Carrión's disease, trench fever, cat-scratch disease, bacillary angiomatosis, and peliosis hepatis. Carrión's disease, known as Oroya fever in the acute phase and verruga peruana (Peruvian wart) in its chronic form, has curious manifestations that, until recently, have been restricted in their geographic distribution to dwellers of the high, dry Andean valleys, but new sites of disease are emerging.

View Article and Find Full Text PDF

Background: Ocular brucellosis is usually diagnosed by clinical criteria and serological tests. Little is known with regard to the ocular immunology of brucellosis and the use of intraocular diagnostic tests. We report retrospectively the laboratory findings of patients with ocular involvement associated with brucellosis.

View Article and Find Full Text PDF

Background: Bartonellosis due to Bartonella bacilliformis is a highly lethal endemic and sometimes epidemic infectious disease in South America, and a serious public health concern in Perú. There is limited information on the immunologic response to B. bacilliformis infection.

View Article and Find Full Text PDF

This study evaluated a new decontamination and concentration (DC) method for sputum microscopy and culture. Sputum samples from patients with suspected pulmonary tuberculosis (TB) (n=106) were tested using the proposed hypertonic saline-sodium hydroxide (HS-SH) DC method, the recommended N-acetyl-L-cysteine-sodium citrate-sodium hydroxide (NALC-NaOH) DC method and unconcentrated direct smear (Ziehl-Neelsen) techniques for the presence of mycobacteria using Löwenstein-Jensen culture and light microscopy. Of 94 valid specimens, 21 (22.

View Article and Find Full Text PDF

Background: Resistance to commonly used antituberculosis drugs is emerging worldwide. Conventional drug-susceptibility testing (DST) methods are slow and demanding. Alternative, rapid DST methods would permit the early detection of drug resistance and, in turn, arrest tuberculosis transmission.

View Article and Find Full Text PDF

We report the use of hypertonic saline and sodium hydroxide (HS-SH) for concentration-decontamination of sputum samples for the diagnosis of tuberculosis. This method increases detection of mycobacteria in smears compared to examination of direct smears, is comparable and reduces contamination in cultures compared to NALC-NaOH.

View Article and Find Full Text PDF

Eight adult patients (ages 18-58, 5 women) with Buruli ulcer (BU) confirmed by at least 2 diagnostic methods were seen in a 10-year period. Attempts to culture Mycobacterium ulcerans failed. Five patients came from jungle areas, and 3 from the swampy northern coast of Peru.

View Article and Find Full Text PDF

Brucellae are tiny, aerobic, slow growing, catalase and oxidase positive Gram negative coccobacilli or small rods, which may reach man through exposure to tissues of mammalian hosts via cuts or aerosols, or as food infections mostly through dairy products. As parasites brucellae are extraordinarily successful, causing very long-lasting infections in all mammalian social animals, such as ungulates, canids, and rodents; recently they have been found to also cause disease in pinnipeds and cetaceans. Brucellae as members of the alpha Proteobacteria, have suffered major losses of genomic material as they adapted to their facultative intracellular parasite role, and are able to initiate infection with minimal disturbance of the innate immune system, thus reaching a privileged intracellular niche where they multiply.

View Article and Find Full Text PDF

Conventional methods for determining drug susceptibility of Mycobacterium tuberculosis require several weeks to obtain results, limiting their usefulness; automated methods and those based on molecular biology techniques have been able to reduce the turnaround time, but their high cost and need for sophisticated equipment restrict their use in developing countries. The goal of the present study was to evaluate the diagnostic accuracy of a rapid (3-4 days) low-cost test based on the use of mycobacteriophage D29 to determine the susceptibility of strains of M. tuberculosis to rifampicin (RIF) and isoniazid (INH).

View Article and Find Full Text PDF

Rhinoscleroma is a rare infection in developed countries; although, it is reported with some frequency in poorer regions such as Central Africa, Central and South America, Eastern and Central Europe, Middle East, India and Indonesia. Nowadays, rhinoscleroma may be erroneously diagnosed as mucocutaneos leishmaniasis, leprosy, paracoccidioidomycosis, rhinosporidiasis, late syphilis, neoplasic diseases or other upper airway diseases. From 1996 to 2003, we diagnosed rhinoscleroma in eight patients attended in the Dermatologic and Transmitted Diseases service of "Cayetano Heredia" National Hospital, in Lima, Peru.

View Article and Find Full Text PDF

Platinum microcoils were placed in porcine lungs to determine the feasibility for use as a lung nodule marker. Using computed tomography (CT) guidance, the microcoils were successfully deployed in 17 out of 19 attempts. Coil deployment depth ranged from 7 mm to 34 mm below the pleural surface.

View Article and Find Full Text PDF

The assessment of antimicrobial resistance among commensal bacteria is an indicator of the spread of antimicrobial resistance. Rapid screening methods for detection of antimicrobial-resistant faecal Escherichia coli directly on MacConkey plates have been successfully adopted but suffer from lack of standardisation. The purpose of this study was to evaluate a direct plating method (DPM) for detection of antimicrobial-resistant faecal E.

View Article and Find Full Text PDF