Phenotypic and Genotypic Characterization of Multidrug-Resistant Bacteroides, Parabacteroides spp., and Pseudoflavonifractor from a Costa Rican Hospital

Address correspondence to: Evelyn Rodríguez-Cavallini, MSc, Laboratorio de Investigación en Bacteriología Anaerobia, Facultad de Microbiología, Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, 2060 San José, Costa Rica, E-mail: [email protected]

Introduction

Worldwide, most anaerobic gram-negative bacterial infections are due to species of Bacteroides and closely related genera.^33,52 These infections, which may be associated with mortality rates approaching 20%,⁵² are usually treated with β-lactam drugs (with or without of β-lactamase inhibitors), carbapenems, clindamycin, metronidazol, and newer quinolones.

Due to the growing number of antibiotic-resistant strains of Bacteroides spp. and related species globally,^4,40 and considering that these bacteria are characterized by a large diversity of resistance mechanisms and high resistance levels,⁴² the CLSI recommends monitoring for antibiotic resistance,²² which can vary by geographic zones and even within healthcare facilities within a single region.^1,39,52 Monitoring activities should be prioritized in developing countries such as Costa Rica, due to a greater potential for misuse in hospitals, the community, and in extrahospitalary settings such as farmlands and livestock in those regions.¹⁰

It is not unusual to find strains of Bacteroides and closely related genera with genes that confer resistance to β-lactams, tetracycline, and clindamycin.⁵² Moreover, strains with acquired resistance to metronidazole or mutations in gyrases that result in quinolone resistance are beginning to emerge.^13,42,52 It is unusual to...