Detection of P. aeruginosa harboring bla CTX-M-2, bla GES-1 and bla GES-5, bla IMP-1 and bla SPM-1 causing infections in Brazilian tertiary-care hospital.

BACKGROUND: Nosocomial infections caused by Pseudomonas aeruginosa presenting resistance to beta-lactam drugs are one of the most challenging targets for antimicrobial therapy, leading to substantial increase in mortality rates in hospitals worldwide. In this context, P. aeruginosa harboring acquired mechanisms of resistance, such as production of metallo-beta-lactamase (MBLs) and extended-spectrum beta-lactamases (ESBLs) have the highest clinical impact. Hence, this study was designed to investigate the presence of genes codifying for MBLs and ESBLs among carbapenem resistant P. aeruginosa isolated in a Brazilian 720-bed teaching tertiary care hospital. METHODS: Fifty-six carbapenem-resistant P. aeruginosa strains were evaluated for the presence of MBL and ESBL genes. Strains presenting MBL and/or ESBL genes were submitted to pulsed-field gel electrophoresis for genetic similarity evaluation. RESULTS: Despite the carbapenem resistance, genes for MBLs (blaSPM-1 or blaIMP-1) were detected in only 26.7% of isolates. Genes encoding ESBLs were detected in 23.2% of isolates. The blaCTX-M-2 was the most prevalent ESBL gene (19.6%), followed by blaGES-1 and blaGES-5 detected in one isolate each. In all isolates presenting MBL phenotype by double-disc synergy test (DDST), the blaSPM-1 or blaIMP-1 genes were detected. In addition, blaIMP-1 was also detected in three isolates which did not display any MBL phenotype. These isolates also presented the blaCTX-M-2 gene. The co-existence of blaCTX-M-2 with blaIMP-1 is presently reported for the first time, as like as co-existence of blaGES-1 with blaIMP-1. CONCLUSIONS: In this study MBLs production was not the major mechanism of resistance to carbapenems, suggesting the occurrence of multidrug efflux pumps, reduction in porin channels and production of other beta-lactamases. The detection of blaCTX-M-2,blaGES-1 and blaGES-5 reflects the recent emergence of ESBLs among antimicrobial resistant P. aeruginosa and the extraordinary ability presented by this pathogen to acquire multiple resistance mechanisms. These findings raise the concern about the future of antimicrobial therapy and the capability of clinical laboratories to detect resistant strains, since simultaneous production of MBLs and ESBLs is known to promote further complexity in phenotypic detection. Occurrence of intra-hospital clonal dissemination enhances the necessity of better observance of infection control practices.

High prevalence of bla(CTX-M) extended spectrum beta-lactamase genes in Klebsiella pneumoniae isolates from a tertiary care hospital: first report of bla(SHV-12), bla(SHV-31), bla(SHV-38), and bla(CTX-M-15) in Brazil.

The aim of this study was to investigate the presence and prevalence of bla(TEM), bla(SHV), and bla(CTX-M) and bla(GES)-like genes, responsible for extended spectrum beta-lactamases (ESBLs) production in clinical isolates of Klebsiella pneumoniae collected from a Brazilian tertiary care hospital. Sixty-five ESBL producing K. pneumoniae isolates, collected between 2005 and 2007, were screened by polymerase chain reaction (PCR). Identification of bla genes was achieved by sequencing. Genotyping of ESBL producing K. pneumoniae was performed by the enterobacterial repetitive intergenic consensus-PCR with cluster analysis by the Dice coefficient. The presence of genes encoding ESBLs was confirmed in 59/65 (90.8%) isolates, comprising 20 bla(CTX-M-2), 14 bla(CTX-M-59), 12 bla(CTX-M-15), 9 bla(SHV-12), 1 bla(SHV-2), 1 bla(SHV-2a), 1 bla(SHV-5), and 1 bla(SHV-31) genes. The ESBL genes bla(SHV-12), bla(SHV-31), and bla(CTX-M-15), and the chromosome-encoded SHV-type beta-lactamase capable of hydrolyzing imipenem were detected in Brazil for the first time. The analysis of the enterobacterial repetitive intergenic consensus-PCR band patterns revealed a high rate of multiclonal bla(CTX-M) carrying K. pneumoniae isolates (70.8%), suggesting that dissemination of encoding plasmids is likely to be the major cause of the high prevalence of these genes among the K. pneumoniae isolates considered in this study.

Intravenous azithromycin plus ceftriaxone followed by oral azithromycin for the treatment of inpatients with community-acquired pneumonia: an open-label, non-comparative multicenter trial.

Community-Acquired Pneumonia (CAP) is a major public health problem. In Brazil it has been estimated that 2,000,000 people are affected by CAP every year. Of those, 780,000 are admitted to hospital, and 30,000 have death as the outcome. This is an open-label, non-comparative study with the purpose of evaluating efficacy, safety, and tolerability levels of IV azithromycin (IVA) and IV ceftriaxone (IVC), followed by oral azithromycin (OA) for the treatment of inpatients with mild to severe CAP. Eighty-six patients (mean age 56.6 +/- 19.8) were administered IVA (500 mg/day) and IVC (1g/day) for 2 to 5 days, followed by AO (500 mg/day) to complete a total of 10 days. At the end of treatment (EOT) and after 30 days (End of Study--EOS) the medication was evaluated clinically, microbiologically and for tolerability levels. Out of the total 86-patient population, 62 (72.1%) completed the study. At the end of treatment, 95.2% (CI95: 88.9% - 100%) reported cure or clinical improvement; at the end of the study, that figure was 88.9% (CI95: 74.1% - 91.7%). Out of the 86 patients enrolled in the study, 15 were microbiologically evaluable for bacteriological response. Of those, 6 reported pathogen eradication at the end of therapy (40%), and 8 reported presumed eradication (53.3%). At end of study evaluation, 9 patients showed pathogen eradication (50%), and 7 showed presumed eradication (38.89%). Therefore, negative cultures were obtained from 93.3% of the patients at EOT, and from 88.9% at the end of the study. One patient (6.67% of patient population) reported presumed microbiological resistance. At study end, 2 patients (11.11%) still reported undetermined culture. Uncontrollable vomiting and worsening pneumonia condition were reported by 2.3% of patients. Discussion and Conclusion Treatment based on the administration of IV azithromycin associated to ceftriaxone and followed by oral azithromycin proved to be efficacious and well-tolerated in the treatment of Brazilian inpatients with CAP.

Intravenous azithromycin plus ceftriaxone followed by oral azithromycin for the treatment of inpatients with community-acquired pneumonia: an open-label, non-comparative multicenter trial

Community-Acquired Pneumonia (CAP) is a major public health problem. In Brazil it has been estimated that 2,000,000 people are affected by CAP every year. Of those, 780,000 are admitted to hospital, and 30,000 have death as the outcome. This is an open-label, non-comparative study with the purpose of evaluating efficacy, safety, and tolerability levels of IV azithromycin (IVA) and IV ceftriaxone (IVC), followed by oral azithromycin (OA) for the treatment of inpatients with mild to severe CAP. Eighty-six patients (mean age 56.6 ± 19.8) were administered IVA (500mg/day) and IVC (1g/day) for 2 to 5 days, followed by AO (500mg/day) to complete a total of 10 days. At the end of treatment (EOT) and after 30 days (End of Study - EOS) the medication was evaluated clinically, microbiologically and for tolerability levels. Out of the total 86-patient population, 62 (72.1 percent) completed the study. At the end of treatment, 95.2 percent (CI95: 88.9 percent - 100 percent) reported cure or clinical improvement; at the end of the study, that figure was 88.9 percent (CI95: 74.1 percent - 91.7 percent). Out of the 86 patients enrolled in the study, 15 were microbiologically evaluable for bacteriological response. Of those, 6 reported pathogen eradication at the end of therapy (40 percent), and 8 reported presumed eradication (53.3 percent). At end of study evaluation, 9 patients showed pathogen eradication (50 percent), and 7 showed presumed eradication (38.89 percent). Therefore, negative cultures were obtained from 93.3 percent of the patients at EOT, and from 88.9 percent at the end of the study. One patient (6.67 percent of patient population) reported presumed microbiological resistance. At study end, 2 patients (11.11 percent) still reported undetermined culture. Uncontrollable vomiting and worsening pneumonia condition were reported by 2.3 percent of patients. Discussion and Conclusion Treatment based on the administration of IV azithromycin...