RESUMEN
The purpose of the study was to investigate the molecular characteristics and genetic relatedness of the first reported cases of vancomycin-resistant enterococci (VRE) from the Tripoli Medical Center, Libya. In total, 43 VRE isolates were obtained from various clinical sites throughout the years 2013-2014, including 40 vanA-type and 2 vanB-type vancomycin-resistant Enterococcus faecium isolates and 1 vanC1-type Enterococcus gallinarum. Of the 42 E. faecium, 19 isolates were subjected to whole genome sequencing. Core genome multilocus sequence typing (cgMLST) analysis revealed three sequence clusters (SCs) of clonally related isolates, which were linked to different hospital wards. The first two VRE isolates, isolated early 2013 from patients in the medical intensive care unit, were grouped in SC1 (MLST [ST] 78, vanB) and differed in only 3 of 1423 cgMLST alleles. The SC2 (n = 16, special care baby unit, neonatal intensive care unit, pediatric surgery ward, and oncology ward) and SC3 (n = 1, antenatal ward) were all ST80 vanA-VRE, but the single SC3 isolate differed in 233 alleles compared with SC2. Within SC2, isolates differed in 1-23 alleles. Comparison with a larger database of E. faecium strains indicated that all isolates clustered within the previously defined hospital clade A1. A combination of Resfinder and mlplasmid analysis identified the presence of resistance genes on different plasmid predicted genetic elements among different SCs. In conclusion, this study documents the first isolates causing outbreaks with VRE in the Libyan health care system. Further surveillance efforts using molecular typing methods to monitor spread of multidrug-resistant bacteria in the Libyan health care system are urgently needed.
Asunto(s)
Farmacorresistencia Bacteriana Múltiple/genética , Enterococcus faecium/genética , Enterococcus faecium/aislamiento & purificación , Enterococos Resistentes a la Vancomicina/genética , Enterococos Resistentes a la Vancomicina/aislamiento & purificación , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Ligasas de Carbono-Oxígeno/genética , Infección Hospitalaria/tratamiento farmacológico , Infección Hospitalaria/microbiología , Brotes de Enfermedades , Enterococcus/efectos de los fármacos , Enterococcus/genética , Enterococcus/aislamiento & purificación , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Infecciones por Bacterias Grampositivas/microbiología , Hospitales , Humanos , Libia , Tipificación de Secuencias Multilocus/métodos , Vancomicina/farmacología , Enterococos Resistentes a la Vancomicina/efectos de los fármacos , Secuenciación Completa del Genoma/métodosRESUMEN
OBJECTIVES: The purpose of the study was to investigate the molecular characteristics of meticillin-resistant Staphylococcus aureus (MRSA) isolated from clinical sources in Tripoli, Libya. METHODS: A total of 95 MRSA strains collected at the Tripoli medical Centre were investigated by spa typing and identification of the Panton-Valentine Leukocidin (pvl) genes. RESULTS: A total of 26 spa types were characterized and distributed among nine clonal complexes; CC5 (n=32), CC80 (n=18), CC8 (n=17) and CC22 (n=12) were the most prevalent clonal complexes. In total, 34% of the isolates were positive for PVL. CONCLUSIONS: This study demonstrated the presence of CA-MRSA and pvl positive strains in hospital settings and underlines the importance of using molecular typing to investigate the epidemiology of MRSA. Preventative measures and surveillance systems are needed to control and minimize the spread of MRSA in the Libyan health care system.
Asunto(s)
Antígenos Bacterianos/genética , Toxinas Bacterianas/genética , Exotoxinas/genética , Genes Bacterianos/genética , Leucocidinas/genética , Staphylococcus aureus Resistente a Meticilina/genética , Epidemiología Molecular , Hospitales , Humanos , Libia , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Tipificación Molecular , Prevalencia , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiologíaAsunto(s)
Acinetobacter baumannii/aislamiento & purificación , Antibacterianos/farmacología , Proteínas Bacterianas/metabolismo , Colistina/farmacología , Farmacorresistencia Bacteriana , Klebsiella/aislamiento & purificación , beta-Lactamasas/metabolismo , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/enzimología , Acinetobacter baumannii/genética , Infección Hospitalaria/microbiología , Infecciones por Bacterias Gramnegativas/microbiología , Instituciones de Salud , Humanos , Imipenem/farmacología , Klebsiella/efectos de los fármacos , Klebsiella/enzimología , Klebsiella/genética , Libia , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias MultilocusRESUMEN
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial (hospital-acquired) pathogen of exceptional concern. It is responsible for life-threatening infections in both the hospital and the community. AIMS: To determine the frequency of MRSA misidentification in hospitals in Tripoli, Libya using current testing methods. METHODS: One hundred and seventy S. aureus isolates previously identified as MRSA were obtained from three hospitals in Tripoli. All isolates were reidentified by culturing on mannitol salt agar, API 20 Staph System and retested for resistance to methicillin using the cefoxitin disk diffusion susceptibility test and PBP2a. D-tests and vancomycin E-tests (Van-E-tests) were also performed for vancomycin-resistant isolates. RESULTS: Of the 170 isolates examined, 86 (51%) were confirmed as MRSA (i.e. 49% were misidentified as MRSA). Fifteen (17%) of the confirmed MRSA strains exhibited inducible clindamycin resistance. Of the 86 confirmed MRSA isolates, 13 (15%) were resistant to mupirocin, 53 (62%) were resistant to ciprofloxacin, 41 (48%) were resistant to trimethoprim-sulfamethoxazole, and none were resistant to linezolid. Although disc-diffusion testing indicated that 23 (27%) of the isolates were resistant to vancomycin, none of the isolates were vancomycin-resistant by Van-E-test. CONCLUSIONS: Misidentification of nosocomial S. aureus as MRSA is a serious problem in Libyan hospitals. There is an urgent need for the proper training of microbiology laboratory technicians in standard antimicrobial susceptibility procedures and the implementation of quality control programs in microbiology laboratories of Libyan hospitals.