Carbapenem-resistant bacilli in a hospital in southern Brazil: prevalence and therapeutic implications

Abstract

Background: Gram-negative bacilli (GNB), notably Acinetobacter spp., Pseudomonas spp., and Klebsiella spp., are becoming increasingly resistant to carbapenems and are associated with high health care costs and mortality, becoming a global concern.

Objective: To determine the prevalence rates of carbapenem resistance among Acinetobacter spp., Pseudomonas spp., and Klebsiella spp. in the main sites of nosocomial infection at a tertiary care hospital in southern Brazil and the consequent therapeutic implications.

Methods: Cultures processed at the institution's laboratory in 2017 were analyzed, and those positive for Acinetobacter spp., Pseudomonas spp., and Klebsiella spp. were identified. Antibiograms were evaluated for meropenem sensitivity following the Clinical Laboratory Standards Institute guidelines.

Results: Acinetobacter spp. had the lowest prevalence among the three GNB, and resistance of this pathogen to meropenem at different sites of infection ranged from 36% (blood) to 82% (respiratory tract). Pseudomonas spp. was highly prevalent at the respiratory tract (31%) and had a high resistance rate to meropenem in rectal swab samples (71%), but a relatively low frequency at infection sites (skin/soft tissue, 13%; blood, 25%). Klebsiella spp. was identified in 7.5% of the blood cultures and 15% of the urine cultures and was the chief colonizer among all pathogens, representing 54% of all rectal swab samples, of which 53% were meropenem resistant. At sites of infection, rates of Klebsiella spp. resistant to meropenem ranged from 19% (skin) to 55% (vascular catheter).

Conclusions: The prevalence of carbapenem-resistant GNB at our hospital was relatively low compared to national and international data; thus, meropenem remains a good therapeutic option against these bacteria. Other antibiotics effective against GNB, such as ceftazidime, cefepime, and piperacillin-tazobactam, can be used in most cases, while meropenem should be reserved for patients with sepsis. Strict contact precaution measures are still needed, given the high resistance rate observed at the colonizing site.

Keywords: Carbapenems; MDR GNB; Prevalence; Susceptibility profile.