RESUMEN

Objectives: Our study aimed to elucidate the clonal diversity of carbapenem-resistant Acinetobacter clinical isolates producing NDM-type carbapenemase collected through national surveillance in Cuba during a 7-year period (2013-19). Methods: A total of 199 isolates of Acinetobacter spp. from 37 hospitals in 12 provinces were genetically analyzed for their species, carbapenemase genes and genotypes. Sequence type (ST) and OXA-51-like gene type were determined for bla NDM-positive isolates. Results: Most isolates (95%) were identified as species of Acinetobacter calcoaceticus-baumannii complex, with A. baumannii being the majority. Acquired carbapenemase genes were assigned to bla OXA or bla NDM type; the most commonly detected gene was bla OXA-23-like (49%), followed by bla OXA-24-like (20%) and bla NDM (15%). Twenty-nine bla NDM-positive isolates (22 A. baumannii, 2 A. pittii, 2 A. johnsonii, 3 other species) were differentiated into 19 STs, including the most common, ST23. Though NDM genes were mostly typed as bla NDM-1, a novel bla NDM-42 was identified in an ST79 A. baumannii isolate. bla OXA-51-like genes of NDM-positive A. baumannii were discriminated into 10 OXA types, including 2 novel ones. Conclusions: Our study indicated the spread of bla NDM to various clones of A. baumannii and other Acinetobacter spp. in Cuba.

RESUMEN

BACKGROUND: The impact of COVID-19 on healthcare- associated infections (HCAI) caused by multidrug-resistant (MDR) bacteria that contribute to higher mortality is a growing area of study METHODS: This retrospective observational study compares the incidence density (ID) of HCAI caused by MDR bacteria (CRE, CRAB, CRP, MRSA and VRE) pre-COVID (2017-2019) and during the COVID-19 pandemic (2020) in overall hospitalized patients and in intensive care (ICU) units. RESULTS: We identified 8,869 HCAI, of which 2,641 (29.7%) were caused by bacterial MDR, and 1,257 (14.1%) were from ICUs. The overall ID of MDR infections increased 23% (P < .005) during COVID-19. The overall per-pathogen analysis shows significant increases in infections by CRAB and MRSA (+108.1%, p<0.005; +94.7%, p<0.005, respectively), but not in CRE, CRP, or VRE. In the ICU, the overall ID of MDR infections decreased during COVID, but that decline was not significant (-6.5%, P = .26). The ICU per-pathogen analysis of ID of infection showed significant increases in CRAB and MRSA (+42.0%, P = .001; +46.2%, P = .04), significant decreases in CRE and CRP (-26.4%, P = .002; -44.2%, P = 0.003, respectively) and no change in VRE. CONCLUSIONS: The COVID-19 pandemic correlates to an increase in ID of CRAB and MRSA both in ICU and non-ICU setting, and a decrease in ID of CRE and CRP in the ICU setting. Infection control teams should be aware of possible outbreaks of CRAB and MRSA and promote rigorous adherence to infection control measures as practices change to accommodate changes in healthcare needs during and after the pandemic.

Asunto(s)

Infecciones Bacterianas , COVID-19 , Infección Hospitalaria , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Infecciones Bacterianas/epidemiología , Brasil/epidemiología , Infección Hospitalaria/tratamiento farmacológico , Infección Hospitalaria/epidemiología , Farmacorresistencia Bacteriana Múltiple , Hospitales , Humanos , Incidencia , Unidades de Cuidados Intensivos , Pandemias , SARS-CoV-2 , Infecciones Estafilocócicas/epidemiología

RESUMEN

Acinetobacter baumannii is an opportunistic pathogen primarily associated with multidrug-resistant nosocomial infections, for which polymyxins are the last-resort antibiotics. This study investigated carbapenem-resistant A. baumannii strains exhibiting an extensively drug-resistant (XDR) phenotype, including four isolates considered locally pan drug-resistant (LPDR), isolated from inpatients during an outbreak at a teaching hospital in Brazil. ApaI DNA macrorestriction followed by PFGE clustered the strains in three pulsotypes, named A to C, among carbapenem-resistant A. baumannii strains. Pulsotypes A and B clustered six polymyxin-resistant A. baumannii strains. MLST analysis of representative strains of pulsotypes A, B, and C showed that they belong, respectively, to sequence types ST1 (clonal complex, CC1), ST79 (CC79), and ST903. Genomic analysis of international clones ST1 and ST79 representative strains predicted a wide resistome for ß-lactams, aminoglycosides, fluoroquinolones, and trimethoprim-sulfamethoxazole, with bla OXA-23 and bla OXA-72 genes encoding carbapenem resistance. Amino acid substitutions in PmrB (Thr232Ile or Pro170Leu) and PmrC (Arg125His) were responsible for polymyxin resistance. Although colistin MICs were all high (MIC ≥ 128 mg/L), polymyxin B MICs varied; strains with Pro170Leu substitution in PmrB had MICs > 128 mg/L, while those with Thr232Ile had lower MICs (16-64 mg/L), irrespective of the clone. Although the first identified polymyxin-resistant A. baumannii strain belonged to ST79, the ST1 strains were endemic and caused the outbreak most likely due to polymyxin B use. The genome comparison of two ST1 strains from the same patient, but one susceptible and the other resistant to polymyxin, revealed mutations in 28 ORFs in addition to pmrBC. The ORF codifying an acyl-CoA dehydrogenase has gained attention due to its fatty acid breakdown and membrane fluidity involvement. However, the role of these mutations in the polymyxin resistance mechanism remains unknown. To prevent the dissemination of XDR bacteria, the hospital infection control committee implemented the patient bathing practice with a 2% chlorhexidine solution, a higher concentration than all A. baumannii chlorhexidine MICs. In conclusion, we showed the emergence of polymyxin resistance due to mutations in the chromosome of the carbapenem-resistant A. baumannii ST1, a high-risk global clone spreading in this hospital.