Elsa Gladys Aguilar-Ancori

Background: The global rise in multidrug-resistant (MDR) Gram-negative bacteria (GNB) poses an urgent challenge for infection control and antibiotic stewardship. Among these, Klebsiella pneumoniae is a major cause of hospital-acquired infections and is listed as a critical priority pathogen by the World Health Organization. Peru reports an exceptionally high prevalence of MDR K. pneumoniae, underscoring the need for innovative antimicrobial approaches. Methods: Here, we describe the isolation and characterization of lytic Klebsiella bacteriophage from sewage samples collected from the Huatanay River (Cusco, Peru) in 2023. Phages were isolated using the reference strain MDR K. pneumoniae ATCC BAA-2814. Then, they were screened against 50 clinical MDR K. pneumoniae strains. Results: The phage H33IIK demonstrated effective antibacterial capability, showing strict host specificity for K. pneumoniae, thermal stability, moderate pH tolerance, and high burst size. Whole-genome sequencing analysis classified it within the class Caudoviricetes, family Ackermannviridae, and genus Taipeivirus. The genomic analysis confirmed the absence of lysogeny-related, antimicrobial resistance, and virulence genes, supporting its suitability and safety for potential biotechnological applications. Conclusions: These findings highlight phage H33IIK as a lytic agent effective against MDR K. pneumoniae. It could contribute to the development of phage-based approaches to combat MDR GNB.

Multidrug-resistant Klebsiella pneumoniae (MDR K. pneumoniae) is a significant pathogen associated with nosocomial infections, often leading to high morbidity and mortality. This resistance is largely due to the efficient horizontal transfer of mobile genetic elements such as plasmids, which carry resistance genes and virulence factors. These elements contribute to the production of extended-spectrum β-lactamases (ESBL) and carbapenemases, which further complicates treatment. Despite the high prevalence of MDR K. pneumoniae in Peruvian hospitals, the genomic characterization of these strains remains limited. This study investigated the phenotypic and molecular identification of extended-spectrum β-lactamases (ESBLs), carbapenemases, and virulence factors in 91 MDR K. pneumoniae strains collected from three hospitals between 2022 and 2023. Phenotypic detection of ESBLs was performed using the Jarlier method, while carbapenemases were identified via double-disk synergy testing with boronic acid, EDTA, and Carba NP test. The positive isolates were further analyzed for resistance genes (blaCTX-M, blaTEM, blaSHV, blaKPC, blaNDM, blaIMP, and blaVIM). Four isolates were subjected to whole-genome sequencing (WGS) for further characterization. All multidrug-resistant K. pneumoniae strains (100%) were ESBL-positive, with 14.3% producing carbapenemases, primarily KPC-type and metallo-β-lactamases (MBLs). The virulence factor analyses revealed that only 7.7% exhibited hypermucoviscosity. Protease activity was detected in 19.8% of the strains, and lipase activity in 1.1%. Regarding biofilm formation, 85.7% of the strains showed moderate adherence. Molecular analysis identified ESBL (blaCTX-M, 78%; blaTEM, 71.4%; blaSHV, 82.4%) and carbapenemase genes (blaKPC 7.7%, blaNDM 4.4%). Genomic analysis revealed various antimicrobial resistance mechanisms, including porin-coding gene mutations, aminoglycoside resistance linked to fluoroquinolone resistance, and multidrug efflux pump regulators. Sequence typing has identified high-risk clones (ST147, ST629, and ST37) associated with hospital outbreaks globally. These findings underscore the considerable concern of MDR and hypervirulent K. pneumoniae in Peruvian hospitals. These findings emphasize the pressing need for sustained genomic surveillance, enhanced infection control measures, and strategies to address the expanding problem of MDR K. pneumoniae.

Background: Cutaneous leishmaniasis (CL) is generally diagnosed by molecular methods, including PCR, using biopsy samples, skin scrapings and clinical exudates. In this study, we assessed the PCR performance for diagnosis of CL using skin of biopsy samples vs PCR of skin lesion exudate samples on filter paper and compared the diagnostic concordance of PCR using both sampling methods. Methods: We assessed the PCR performance using 80 skin biopsy samples and 80 filter paper samples containing exudates from skin lesions obtained from 74 patients with clinical suspicion of CL in Cusco, Peru. Results: : PCR using skin biopsy samples had superior diagnostic accuracy compared with filter paper PCR (62.5% [50/80] vs 38.7% [31/80], respectively; p˂0.005) and the diagnostic concordance between both sampling methods was ‘moderate’ (kappa coefficient=0.50, 95% CI 0.98 to 1.0). Conclusions: PCR using biopsy samples remains the standard for diagnosis of CL.

Pintomyia (Pifanomyia) deorsa (Pérez, Ogusuku, Monje & Young, 1991) was described on the basis of a single male; the female is being described here from specimens collected in Ollantaytambo, Cusco, Peru. Diagnoses for the Pintomyia genus, Pifanomyia subgenus, Verrucarum series and both sexes of Pi. deorsa are presented, as well as an identification key to distinguish the females of the Verrucarum series.

Ecological determinants of sporotrichosis etiological agents remain poorly understood. For this reason, we performed explorations using local climate estimates to determine the temperature and humidity ranges of the environment where clinically relevant Sporothrix species occur and to identify what plant species are associated with them, using data collected from the published literature. We performed a literature search to identify all publications on environmental isolations of medically relevant species of Sporothrix in the PubMed, SCOPUS, and EMBASE databases. All those studies were included in the analysis where medically relevant species of Sporothrix have been isolated from soil samples, and described a specific geographical location that could be precisely georeferenced. We approximated temperature and humidity from local climate estimates, integrating geospatial data, temperature, and water vapor pressure from regions or provinces where medically relevant species of Sporothrix have been isolated from soil. Sporothrix spp. were more commonly isolated from soil of different regions or provinces of 16 countries. Most environmental isolates were identified as S. schenckii, whereas S. pallida, S. brasiliensis, S. globosa, and S. mexicana were rare. We estimate that medically relevant Sporothrix spp. grow in the soil at temperatures of 6.6 °C to 28.84 °C and 37.5% to 99.06% relative humidity. These findings indicate that sporotrichosis etiological agents grow in soil in ecological niches from soil with wide ranges of temperature and humidity, but they are also associated with a variety of plants, flowers, woody debris, reed leaves, corn stalks, leaves, and wood crumbs, potentially facilitating its establishment and proliferation in the environment.

Actividad antibacteriana frente a Streptococcus mutans de aceites esenciales de cinco plantas alto andinas

Para determinar la prevalencia de marcadores serológicos de hepatitis viral B en estudiantes universitarios de la ciudad de Abancay, realizamos un estudio transversal en 240 estudiantes de tres universidades, entre enero a octubre de 2010. Previo consentimiento informado, se llenó, por cada estudiante, una ficha epidemiológica y se tomó una muestra sanguínea para determinar la presencia de HBsAg, anti-HBcAg total, anti-HBe, HBeAg e IgM anti-HBc por el método de ELISA. Se encontró una prevalencia de 2,5 % (seis seropositivos) para el HBsAg y 28,3 % (68 seropositivos) para los anticuerpos Anti-HBcAg. El sexo masculino estuvo asociado con la presencia del anti-HBcAg (OR = 2,0; IC 95 %, 1,2- 3,6). No se encontró la presencia del HBeAg e IgM anti-HBc; los seis portadores del HBsAg fueron anti-HBe positivos. En conclusión, la infección por hepatitis B sigue siendo un problema de salud pública en Abancay, con una prevalencia importante en estudiantes universitarios.