Gram-negative osteomyelitis: clinical and microbiological profile

INTRODUCTION: Despite the growing interest in the study of Gram-negative bacilli (GNB) infections, very little information on osteomyelitis caused by GNB is available in the medical literature. OBJECTIVES AND METHODS: To assess clinical and microbiological features of 101 cases of osteomyelitis caused by GNB alone, between January 2007 and January 2009, in a reference center for the treatment of high complexity traumas in the city of São Paulo. RESULTS: Most patients were men (63 percent), with median age of 42 years, affected by chronic osteomyelitis (43 percent) or acute osteomyelitis associated to open fractures (32 percent), the majority on the lower limbs (71 percent). The patients were treated with antibiotics as inpatients for 40 days (median) and for 99 days (median) in outpatient settings. After 6 months follow-up, the clinical remission rate was around 60 percent, relapse 19 percent, amputation 7 percent, and death 5 percent. Nine percent of cases were lost to follow-up. A total of 121 GNB was isolated from 101 clinical samples. The most frequently isolated pathogens were Enterobacter sp. (25 percent), Acinetobacter baumannii (21 percent) e Pseudomonas aeruginosa (20 percent). Susceptibility to carbapenems was about 100 percent for Enterobacter sp., 75 percent for Pseudomonas aeruginosa and 60 percent for Acinetobacter baumannii. CONCLUSION: Osteomyelitis caused by GNB remains a serious therapeutic challenge, especially when associated to nonfermenting bacteria. We emphasize the need to consider these agents in diagnosed cases of osteomyelitis, so that an ideal antimicrobial treatment can be administered since the very beginning of the therapy.

Carbapenem stewardship: positive impact on hospital ecology

INTRODUCTION: Excessive group 2 carbapenem use may result in decreased bacterial susceptibility. OBJECTIVE: We evaluated the impact of a carbapenem stewardship program, restricting imipenem and meropenem use. METHODS: Ertapenem was mandated for ESBL-producing Enterobacteriaceae infections in the absence of non-fermenting Gram-negative bacilli (GNB) from April 2006 to March 2008. Group 2 carbapenems were restricted for use against GNB infections susceptible only to carbapenems and suspected GNB infections in unstable patients. Cumulative susceptibility tests were done for nosocomial pathogens before and after restriction using Clinical and Laboratory Standards Institute (CLSI) guide-lines.Vitek System or conventional identification methods were performed and susceptibility testing done by disk diffusion according to CLSI.Antibiotic consumption (t-test) and susceptibilities (McNemar's test) were determined. RESULTS: The defined daily doses (DDD) of group 2 carbapenems declined from 61.1 to 48.7 DDD/1,000 patient-days two years after ertapenem introduction (p = 0.027). Mean ertapenem consumption after restriction was 31.5 DDD/1,000 patient-days. Following ertapenem introduction no significant susceptibility changes were noticed among Gram-positive cocci. The most prevalent GNB were P. aeruginosa, Klebsiella pneumoniae, and Acinetobacter spp. There was no change in P. aeruginosa susceptibility to carbapenems. Significantly improved P. aeruginosa and K. pneumoniae ciprofloxacin susceptibilities were observed, perhaps due to decreased group 2 carbapenem use. K. pneumoniae susceptibility to trimethoprim-sulfamethoxazole improved. CONCLUSION: Preferential use of ertapenem resulted in reduced group 2 carbapenem use, with a positive impact on P. aeruginosa and K. pneumoniae susceptibility.

Economic impact of treatment for surgical site infections in cases of total knee arthroplasty in a tertiary public hospital in Brazil

The aim of this study was to estimate the additional cost of treatment of a group of nosocomial infections in a tertiary public hospital. A retrospective observational cohort study was conducted by means of analyzing the medical records of 34 patients with infection after total knee arthroplasty, diagnosed in 2006 and 2007, who met the criteria for nosocomial infection according to the Centers for Disease Control and Prevention. To estimate the direct costs of treatment for these patients, the following data were gathered: length of hospital stay, laboratory tests, imaging examinations, and surgical procedures performed. Their costs were estimated from the minimum values according to the Brazilian Medical Association. The estimated cost of the antibiotics used was also obtained. The total length of stay in the ward was 976 days, at a cost of US$ 18,994.63, and, in the intensive care unit, it was 34 days at a cost of US$ 5,031.37. Forty-two debridement procedures were performed, at a cost of US$ 5,798.06, and 1965 tests (laboratory and imaging) were also performed, at a cost of US$ 15,359.25. US$ 20,845.01 was spent on antibiotics and US$ 1,735.16 on vacuum assisted closure therapy, microsurgical flaps, implant removal, spacer use, and surgical revision. The total additional cost of these cases of hospital infection in 2006 and 2007 was of US$ 91,843.75. Based on that, we demonstrate that the high cost of treatment for hospital infections emphasizes the importance of taking measures to prevent and control hospital infection.

Inibidores da bomba protônica / Proton pump inhibitors

Os estudos sobre o efeito do controle do ácido gástrico iniciaram-se há mais de 30 anos. Desde então, inúmeros ensaios clínicos bem conduzidos e metanálises mostraram que os inibidores da bomba protônica (IBP) são significativamente mais efetivos que antagonistas dos receptores H2 da histamina para a realização da supressão ácida gástrica. A secreção ácida nas células parietais do estômago cria um fluxo de íons, em que prótons são bombeados de fluidos intracelulares para o lúmen gástrico contra um gradiente. A engenharia enzimática responsável por esse transporte ativo é a bomba H+,K+ ATPase, a qual é modulada (estimulação e inibição) por sinais moleculares neuronais e endócrinos. Os IBP, após a ingestão antes da alimentação, ligam-se apenas às bombas ativadas. São metabolizados pelo complexo enzimático do citocromo P450, CYP 2C19 e CYP 3A4, esta característica contribui para interações medicamentosas com outros fármacos que também possuem o mesmo mecanismo de metabolização. Os IBP, geralmente, são bem tolerados pelo organismo. Até o momento, estudos descreveram que as reações adversas mais comuns relatadas são: dor de cabeça, diarréia e náusea, com incidência de < 10%, valores semelhantes quando comparados com placebo e antagonistas dos receptores H2. A terapia de supressão ácida com IBP está associada a benefícios no manejo de doenças ácido-pépticas. O sucesso desta supressão farmacológica para o processo de cicatrização de úlcera e DRGE está refletindo-se na redução de cirurgias eletivas como tratamento destas enfermidades, além da redução da gastropatia associada à utilização de AINEs.