RESUMEN

In methicillin-resistant Staphylococcus aureus (MRSA) treatment, the vancomycin minimum inhibitory concentration (MIC) increase, vancomycin heteroresistance (hVISA) presence, and accessory gene regulator (agr) dysfunction are predictors of vancomycin therapy failure. This study evaluated the association between vancomycin MIC (≥ 1.0 µg/mL) and agr dysfunction in invasive MRSA isolates. Vancomycin MIC, hVISA phenotype, agr group, and function were determined in 171 MRSA isolates obtained between 2014 and 2019 from hospitals in Porto Alegre, Brazil. All MRSA were susceptible to vancomycin; 16.4% of these had MIC ≥ 1.0 µg/mL. Seventeen MRSA isolates expressed the hVISA phenotype; 35.3% of them had MIC of 1.5 µg/mL. agr groups I (40.9%) and II (47.1%) were the most found groups for MRSA and hVISA isolates, respectively. The proportion of MRSA with vancomycin MIC ≥ 1.0 µg/mL in agr group II was significantly higher than in agr groups I and III (p = 0.002). agr dysfunction was observed in 4.7% (8/171) of MRSA, especially those with vancomycin MIC ≥ 1.0 µg/mL (p < 0.001). In addition, six isolates (35.3%; 6/17) with hVISA phenotype presented agr dysfunction, which was significantly higher than that in non-hVISA phenotype (p < 0.001). In conclusion, agr dysfunction in MRSA is associated with vancomycin MIC ≥ 1.0 µg/mL and hVISA phenotype, which suggests that agr dysfunction might confer potential advantages on MRSA to survive in invasive infections.

Asunto(s)

Asunto(s)

RESUMEN

We report changes in the molecular epidemiology of vanA-containing Enterococcus during the intra and interhospital spread of high-risk clones, in Southeastern Brazil. While VRE faecalis predominated during 1998 to 2006, a reversal has been observed in the last years, where VRE faecium belonging to ST114, ST203, ST412, ST478 and ST858 have become endemic.

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

Currently, there is a pressing need for novel antibacterial agents against drug-resistant bacteria, especially those which have been common in our communities and hospitals, such as methicillin-resistant Staphylococcus aureus (MRSA). The South American plant Achyrocline satureioides ("Marcela") has been widely used in traditional medicine for a number of diseases, including infections. Several crude extracts from this plant have shown good antimicrobial activities in vitro. In the search for the active principle(s) that confers these antimicrobial activities, we have processed the dichloromethane extract from the aerial parts of the plant. One of the isolated compounds showed extraordinary antibacterial activities against a set of clinically relevant Gram-positive strains that widely differ in their antibiogram profiles. This compound was identified as achyrofuran on the basis of its spectroscopic and physical data. We determined the MIC to be around 0.1 µM (0.07 µg/ml) for the reference methicillin-resistant and vancomycin-intermediate S. aureus strain NRS402. Moreover, nanomolar concentrations of achyrofuran killed 10(6) bacteria within 12 h. Based on the presence of the 2,2'-biphenol core, we further studied whether achyrofuran killed bacteria through a mechanism of action similar to that reported for the naturally occurring antibiotic MC21-A. Indeed, we found that achyrofuran was not bacteriolytic by itself although it greatly compromised membrane impermeability as determined by increased SYTOX Green uptake.

Asunto(s)

RESUMEN

The reduction in time required to identify vancomycin-resistant enterococci (VRE) has gained increased importance during hospital outbreaks. In the present study, we implemented a laboratory protocol to speed up the VRE screening from rectal samples. The protocol combines a medium for selective VRE isolation (VREBAC®, Probac, São Paulo) and a multiplex PCR for detection and identification of vanA and vanB resistance genes. The screening performance was analyzed in 114 specimens collected from four intensive care units. The swabs were collected at two periods: (1) during a VRE outbreak (February 2006, n=83 patients) and (2) at the post-outbreak period, after adoption of infection control measures (June 2006, n=31 patients). Forty-one/83 VRE (49.4 percent) and 3/31(9.7 percent) VRE were found at the first and second period, respectively. All isolates harbored the vanA gene. In both periods, detection of the gene vanA parallels to the minimum inhibitory concentration values of >256 µg/mL and >48 µg/mL for vancomycin and teicoplanin, respectively. Multiplex PCR and conventional methods agreed in 90.2 percent for enterococci identification. Besides this accuracy, we also found a remarkable reduction in time to obtain results. Detection of enterococcal species and identification of vancomycin resistance genes were ready in 29.5 hours, in comparison to 72 hours needed by the conventional methods. In conclusion, our protocol identified properly and rapidly enterococci species and vancomycin-resistance genes. The results strongly encourage its adoption by microbiology laboratories for VRE screenning in rectal samples.

Asunto(s)

RESUMEN

Enterococci are part of the endogenous flora of human beings, are naturally resistant to several classes of antimicrobials, and are able to acquire resistance with relative ease. Currently the vancomycin-resistant enterococci are spread all over the world and treatment options for infections caused by it are often extremely limited. We assessed 193 vancomycin-resistant Enterococcus faecalis isolates collected from four different hospitals in Porto Alegre for their susceptibility to fosfomycin using the E-test and agar diffusion. Fosfomycin proved to be active in vitro against the great majority of isolates, indicating that it is a valid option in the treatment of these infections.

Asunto(s)

RESUMEN

The reduction in time required to identify vancomycin-resistant enterococci (VRE) has gained increased importance during hospital outbreaks. In the present study, we implemented a laboratory protocol to speed up the VRE screening from rectal samples. The protocol combines a medium for selective VRE isolation (VREBAC(R), Probac, São Paulo) and a multiplex PCR for detection and identification of vanA and vanB resistance genes. The screening performance was analyzed in 114 specimens collected from four intensive care units. The swabs were collected at two periods: (1) during a VRE outbreak (February 2006, n=83 patients) and (2) at the post-outbreak period, after adoption of infection control measures (June 2006, n=31 patients). Forty-one/83 VRE (49.4%) and 3/31(9.7%) VRE were found at the first and second period, respectively. All isolates harbored the vanA gene. In both periods, detection of the gene vanA parallels to the minimum inhibitory concentration values of >256 microg/mL and >48 microg/mL for vancomycin and teicoplanin, respectively. Multiplex PCR and conventional methods agreed in 90.2% for enterococci identification. Besides this accuracy, we also found a remarkable reduction in time to obtain results. Detection of enterococcal species and identification of vancomycin resistance genes were ready in 29.5 hours, in comparison to 72 hours needed by the conventional methods. In conclusion, our protocol identified properly and rapidly enterococci species and vancomycin-resistance genes. The results strongly encourage its adoption by microbiology laboratories for VRE screening in rectal samples.

Asunto(s)

RESUMEN

Enterococci are part of the endogenous flora of human beings, are naturally resistant to several classes of antimicrobials, and are able to acquire resistance with relative ease. Currently the vancomycin-resistant enterococci are spread all over the world and treatment options for infections caused by it are often extremely limited. We assessed 193 vancomycin-resistant Enterococcus faecalis isolates collected from four different hospitals in Porto Alegre for their susceptibility to fosfomycin using the E-test and agar diffusion. Fosfomycin proved to be active in vitro against the great majority of isolates, indicating that it is a valid option in the treatment of these infections.

Asunto(s)

RESUMEN

OBJECTIVE: To describe the use of linezolid in vancomycin-resistant Enterococcus infections in a paediatric hospital. METHOD: Retrospective, observational study of hospitalised patients at the "Juan P. Garrahan" paediatric hospital receiving linezolid for the treatment of vancomycin-resistant Enterococcus, during the period between January 2002 and July 2004. RESULTS: During 18 months, linezolid was prescribed 17 times for a total of 15 seriously ill patients. The median age was 7 years old (range: 1 month-15 years) and the median length of the treatment was 15 days, with an average hospital stay of 74 days. Infection with vancomycin-resistant Enterococcus was microbiologically documented in 11 (73.3%) patients; they all responded to treatment with linezolid with the exception of two, who died while receiving treatment. The most frequently reported adverse reactions were of a haematological nature (55.5%). CONCLUSIONS: Linezolid was effective and moderately well tolerated for the treatment of vancomycin-resistant Enterococcus in children with life-threatening infections.

Asunto(s)