The incidence and microbiological profile of surgical site infections following internal fixation of closed and open fractures / Infecção de sítio cirúrgico após fixação de fraturas fechadas e expostas - Incidência e perfil microbiológico

ABSTRACT OBJECTIVE: To evaluate the incidence and microbiological profile of surgical site infections (SSIs) associated with internal fixation of fractures and to compare differences in the SSIs observed among patients with closed and open fractures. METHODS: Retrospective study. Analyzed data included information from all patients who underwent surgery for fixation of closed or open fractures from January 2005 to December 2012 and remained outpatients for at least one year following surgery. Incidence of surgical site infection (SSI) was compared between patients with closed and open infection, as well as polymicrobial infection and infection related to Gram-negative bacilli (GNB). Cumulative antibiograms were performed to describe microbiological profiles. RESULTS: Overall incidence of SSI was 6%. This incidence was significantly higher among patients with open fractures (14.7%) than among patients with closed fractures (4.2%). The proportions of patients with polymicrobial infections and infections due to GNB were also significantly higher among patients with open fractures. Staphylococcus aureus and coagulase-negative Staphylococcus (CoNS) species were the primary infectious agents isolated from both groups. The overall incidence of MRSA (methicillin-resistant S. aureus) was 72%. A. baumannii was the predominant GNB isolate recovered from patients with open fractures and P. aeruginosa was the most frequent isolate recovered from patients with closed fractures, both exhibited low rates of susceptibility to carbapenems. CONCLUSIONS: Incidence of SSIs related to the internal fixation of fractures was significantly higher among patients with open fractures, indicating that an open fracture can be a risk factor for infection. Among the bacterial isolates, S. aureus (with a high prevalence of MRSA) and CoNS species were most prevalent. A. baumannii and P. aeruginosa isolates underscored the low rate of susceptibility to carbapenems that was observed in the present study.

RESUMO OBJETIVO: Avaliar a incidência e o perfil microbiológico das ISC relacionadas a procedimentos de fixação de fraturas num hospital acadêmico ortopédico terciário em São Paulo, Brasil, e comparar as diferenças observadas entre os pacientes com fraturas fechadas e expostas. MÉTODOS: Estudo retrospectivo. Foram incluídos na análise os dados relativos a todos os pacientes que passaram por procedimento cirúrgico para fixação de fraturas fechadas ou expostas de janeiro de 2005 a dezembro de 2012 e que mantiveram seguimento por pelo menos um ano. Foi verificada a presença de associação entre o tipo de fratura, a incidência de ISC e as incidências de infecções polimicrobianas e por bacilos Gram-negativos. O perfil microbiológico foi estabelecido por meio da elaboração de antibiogramas cumulativos. RESULTADOS: A incidência geral de infecção de 6%. Essa incidência foi maior no grupo de pacientes com fraturas expostas (14,7%) do que naqueles com fraturas fechadas (4,2%), com diferença estatisticamente significante. O número de pacientes com infecções polimicrobianas e com infecções relacionadas a BGN também foi significativamente maior no grupo de casos relacionados a fraturas expostas. Staphylococcus aureus e espécies de Staphylococcus coagulase-negativo (CoNS) foram os principais agentes isolados nos dois grupos. A incidência de MRSA (S. aureus resistente a meticilina) dentre todos os isolados de S. aureus foi de 72%. A. baumannii foi o principal BGN isolado entre os pacientes com fraturas expostas e P. aeruginosa entre os pacientes com fraturas fechadas. Em ambos os casos, observaram-se baixos índices de sensibilidade a carbapenêmicos. CONCLUSÕES: A incidência de ISC relacionada à fixação interna de fraturas foi significantemente maior nos pacientes com fraturas expostas, o que indica que esse tipo de fratura pode ser um fator de risco para a ocorrência desse tipo de infecção. Dentre os isolados bacterianos, predominaram no geral S. aureus (com elevada prevalência de MRSA) e S. coagulase-negativo. Dentre os BGN, houve predomínio de A. baumanni também entre os isolados de pacientes com fraturas expostas e P. aeruginosa entre os isolados daqueles com fraturas fechadas.

Outpatient parenteral antimicrobial therapy for orthopedic infections – a successful public healthcare experience in Brazil

Abstract Treatment of orthopedic infections usually requires prolonged antimicrobial therapy, ranging from 14 days up to 6 months. Nowadays, rising levels of antimicrobial resistance demands parenteral therapy for many patients. Outpatient parenteral antimicrobial therapy (OPAT) is a modality that allows treatment out of hospital in these situations. In Brazil, where a public universal healthcare system allows full coverage for all citizens, implantation and dissemination of OPAT programs would be beneficial for patients and for the system, because it would allow a better allocation of health resources. The Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Faculdade de Medicina da USP (IOT) started, in July 2013, a partnership with municipal health authorities in Sao Paulo, Brazil, in order to initiate an OPAT program in which patients discharged from that hospital would be able to continue antimicrobial therapy at primary care facilities. When necessary, patients could also receive their therapy at the day-hospital located at IOT. Primary care nursing and physician staff were trained about antimicrobial infusion and peripherally inserted central catheter manipulation. An OPAT specific antimicrobial protocol was designed and a special reference and counter-reference organized. As a result, 450 primary healthcare professionals were trained. In the first year of this program, 116 patients were discharged for OPAT. Chronic and acute osteomyelitis were most frequent diagnosis. Teicoplanin, ertapenem and tigecycline were the most used drugs. Duration of treatment varied from 10 to 180 days (average 101, median 42). Total sum of days in OPAT regimen was 11,698. Only 3 patients presented adverse effects. Partnership between services of different levels of complexity allowed implantation of a safe and effective public healthcare OPAT program for treatment of orthopedic infections. This program can serve as a model for developing similar strategies in other regions of Brazil and Latin America.

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.