Usually, community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is susceptible to a variety of non-beta-lactam drugs. These isolates commonly display SCCmecIV and are associated with community-acquired infections. More recently, CA-MRSA has been isolated from health-care-associated diseases. We characterized MRSA isolates from 2 hospitals in Rio de Janeiro area to assess the entry of new lineages. The isolates were primary genotyped using a combination of molecular typing methods including SCCmec, restriction modification test, and Panton-Valentine leukocidin (PVL) detection. Pulsed-field gel electrophoresis was carried out for representatives of each lineages found. Disk diffusion test was performed as recommended by the Clinical and Laboratory Standards Institute. SCCmecIV was the predominant cassette mec detected. The most frequent MRSA lineage, a PVL nonproducer, was allocated in the CC1-SCCmecIV. It was found that 56% of these isolates were resistant to 3 or more non-beta-lactam drugs. Multilocus sequence typing of a representative of the CC1 isolates supported our finds that multiresistant variants of a CA-MRSA lineage (ST1-SCCmecIV) emerged in this city.

Vários derivados de 1,4-naftoquinonas contendo um grupo hidrazino como cadeia lateral foram sintetizados a partir do 3-diazo-naftaleno-1,2,4-triona e foram avaliados como potenciais agentes antimicrobianos. Os derivados naftoquinônicos 2--hidrazono]-malonato de etila mostraram maior atividade antibacteriana, ao nível de teste preliminar em disco, que o lapachol (1), uma 1,4-naftoquinona muito conhecida pelas suas variadas atividades biológicas. Estudo sobre a concentração mínima inibitória (MIC) para o Staphylococcus aureus mostrou que 2-[(3-hidroxi-1,4-dioxo-1,4-diidronaftaleno-2-il)-hidrazono]-malonato de etila tem uma atividade duas vezes maior que 1. Da mesma forma, o estudo da densidade ótica em cultura de S. aureus com esta substância mostrou uma atividade similar à da vancomicina na concentração de 2xMIC.Several 1,4-naphthoquinone derivatives having a hydrazino side chain were synthesized from 3-diazo-naphthalene-1,2,4-trione and tested as potential antimicrobial agents. These naphthoquinone derivatives 2-[N'-(1-acetyl-2-oxo-propylidene)-hydrazino]-3-hydroxy-[1,4]naphthoquinone, ethyl 2-[(3-hydroxy-1,4-dioxo-1,4-dihydro-naphthalen-2-yl)-hydrazono]-3-oxo-butyrate, t-butyl 2-[(3-hydroxy-1,4-dioxo-1,4-dihydro-naphthalen-2-yl)-hydrazono]-3-oxobutyrate, 3-hydroxy-2-[(di-O-isopropylidene-malonate)-hydrazino]-1,4-naphthoquinone, and diethyl 2-[(3-hydroxy-1,4-dioxo-1,4-dihydro-naphthalen-2-yl)-hydrazono]-malonate showed greater antibacterial activity at the level of the preliminary susceptibility testing in disk than lapachol (1), a well known 1,4-naphthoquinone which has several biological activities. Studies on the minimal inhibitory concentration (MIC) for Staphylococcus aureus showed that diethyl 2-[(3-hydroxy-1,4-dioxo-1,4-dihydro-naphthalen-2-yl)-hydrazono]-malonate has an activity twofold greater than 1. On the other hand, optical density measurement for S. aureus indicated that this compound has similar activity compared with vancomycin at 2xMIC.

Ninety-three isolates were screened as ESBL positive and 85 (91%) were found to carry CTX-M-type, as follows: K. pneumoniae 59 (49%), E. cloacae 15 (42%), and E. coli 11 (15%). Ten isolates resistant for carbapenems in K. pneumoniae were blaKPC-2 gene positive. Among CTX-M type isolates, CTX-M-15 was predominant in more than 50% of isolates for K. pneumoniae, E. coli, and E. cloacae. PFGE analysis of CTX-M producing isolates showed the predominance of CTX-M-15 in 10 of 24 pulsotypes in K. pneumoniae, 6 of 13 in E. cloacae and 3 of 6 in E. coli. CTX-M-15 was also predominant among KPC producing isolates. In conclusion, this study showed that CTX-M-15 was circulating in Rio de Janeiro state in 2007-2008. This data reinforce the need for continuing surveillance because this scenario may have changed over the years.

OXA-23-like enzymes may be an important mechanism of carbapenem resistance among isolates present in the hospital studied.