Changing patterns of acute hematogenous osteomyelitis and septic arthritis: emergence of community-associated methicillin-resistant Staphylococcus aureus

INTRODUCTION: An increase in the incidence and severity of acute osteoarticular infections in children was perceived after the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) in our community. This study was performed to describe changes in the epidemiology and clinical features of acute osteoarticular infections. METHODS: The records of patients discharged from Le Bonheur Children's Medical Center with a diagnosis of acute osteoarticular infection between 2000 and 2004 were reviewed. Data regarding signs and symptoms, diagnostic testing, therapeutics, surgery, and hospital course were collected. RESULTS: There were 158 cases of acute osteoarticular infection. The incidence increased from 2.6 to 6.0 per 1000 admissions between 2000 and 2004. The proportion of infections caused by methicillin-susceptible S. aureus (MSSA) remained constant (10%-13%) and that caused by MRSA rose from 4% to 40%. There was no difference between MRSA and MSSA patients in the duration of fever or pain before diagnosis. Seventy-one percent of patients with MRSA had subperiosteal abscesses compared with 38% with MSSA (P = 0.02). Ninety-one percent of MRSA patients required a surgical procedure compared with 62% of MSSA patients (P < 0.001). Median hospital stay was 7 days for MSSA patients and 10 days for MRSA patients (P = 0.0001). Three patients developed chronic osteomyelitis, 2 with MRSA. There was no association between a delay in institution of appropriate antibiotic therapy and presence of subperiosteal abscess (P = 0.8). CONCLUSIONS: There has been an increase in the incidence and severity of acute osteoarticular infections in Memphis. Patients with community-associated MRSA infections are at higher risk of subperiosteal abscess requiring surgical intervention.     

Community-acquired methicillin-resistant Staphylococcus aureus infections in otolaryngology.

Soon after the introduction of methicillin, strains of Staphylococcus aureus resistant to methicillin were reported. Methicillin-resistant Staphylococcus aureus (MRSA) has become a common hospital pathogen, often resistant to multiple antibiotics, while causing significant morbidity and mortality. Community-acquired MRSA infections have been infrequently documented. Most reports have been associated with intravenous drug abuse. This report reviews 15 patients with community-acquired MRSA infections of the head and neck. None admitted to intravenous drug use. Additionally, no patient was known to be a healthcare worker. The MRSA strains showed antibiotic susceptibility and resistance profiles different from typical hospital-acquired MRSA isolates. All but one infection resolved with adequate surgical or appropriate antibiotic therapy. Clinicians should become aware of the possibility of community-acquired MRSA in the patient who has had continued infection despite antibiotic therapy.     

Emergence of community-acquired methicillin-resistant Staphylococcus aureus soft tissue infections

Purpose

Our objective is to describe the changing incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) and its treatment within East Tennessee.

Methods

A retrospective chart review of 245 patients treated with incision and drainage of soft tissue infections from March 2000 to September 2005 was completed. Consent was obtained from our local institutional review board. Forty patients were excluded because no cultures were recorded or because they failed the criteria for the diagnosis of CA-MRSA. We examined our data using χ² analysis. P value of less than .05 was considered statistically significant.

Results

The most common organism cultured was CA-MRSA (33%; 67 of 205). Non-CA-MRSA accounted for 4% (9 of 205). The age of patients ranged from 1 month to 21 years, with a mean age of 6.5 years. Stratified by year, the incidence of positive cultures for CA-MRSA has increased 159% since 2004 and 868% since 2003. In addition, the average age of patients has decreased from 8.3 years in 2000 to 6.1 years in 2005.

Conclusions

Community-acquired MRSA has emerged as the dominant source of soft tissue infection requiring incision and drainage regardless of site in East Tennessee. This has caused a change in the choice of empiric antibiotic treatment of soft tissue abscesses in our region. These infections now account for the third most common reportable disease to the Department of Health in East Tennessee.     

Risk factors and treatment of methicillin-resistant Staphylococcus aureus infections

METICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS INFECTIONS (MRSA): The maintenance of a catheter in febrile neutropenic patients with MRSA bacteremia is justified, except when the latter persists 2 to 3 days after the initiation of treatment. Prior administration of fluoroquinolones (levofloxacine or ciprofloxacine) is a risk factor significantly associated with the isolation of MRSA. Meticillin resistance is not a factor of mortality in HIV-infected patients exhibiting S. aureus bacteremia. Surveillance blood cultures represent a simple method for identifying patients at high risk of secondary foci. INFECTIONS WITH GLYCOPEPTIDE-INTERMEDIATE MRSA (HETERO-GISA): In liver transplant recipients, the risk of acquiring a hetero-GISA is not associated with prior MRSA infection nor prior glycopeptide treatment. It is significantly associated with the occurrence of an infectious episode in the weeks preceding the transplant and with the administration of beta-lactams during the previous two months. Mortality is not increased in patients with hetero-GISA. NEW ANTIBIOTICS: Linezolide and quinupristine-dalfopristine are new agents available for the treatment of MRSA infection. Other antibiotics under development have demonstrated their activity: lipopeptides (daptomycin), semi-synthetic glycopeptides (oritavancin, dalbavancin), glycylglycines (tigecyclin), carbapenems (CP5609), and cephalosphorins (LB 11058). ANTIBIOTIC COMBINATIONS: Various studies have shown that antibiotic combinations must be used with care in the treatment of MRSA and GISA infections (glycopeptide intermediate strains) because of the antagonism between molecules belonging to different families.     

Daptomycin for methicillin-resistant Staphylococcus aureus infections of the spine

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) infection is increasingly common. Treatment with vancomycin-based therapy is often unsuccessful. Daptomycin is a relatively new lipopeptide antibiotic with potent activity against MRSA.PurposeTo describe the successful management of MRSA infection involving the spine.Study designTwo case reports of MRSA infection, one involving epidural and lumbar subdural abscesses, the other with osteomyelitis and discitis.MethodsTwo cases are described, one with lumbar epidural and subdural abscesses and the other with osteomyelitis and discitis of the spine. Switching from vancomycin to daptomycin plus rifampin-based therapy resulted in patient improvement that allowed discharge from the hospital.ResultsBoth patients recovered fully from their infection.ConclusionsDaptomycin is a safe and effective option for the treatment of MRSA infection involving the spine.     

Community-associated methicillin-resistant Staphylococcus aureus hand infections in an urban setting

PURPOSE: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection appears to be increasing. The purpose of this study was to determine prospectively the incidence of MRSA in community-associated hand infections in an urban hospital. METHODS: Sixty-one patients presented to our institution over a 9-month period with community-acquired hand infections that were evaluated and treated by the hand service. The specimens obtained during the initial evaluation and treatment were cultured and subjected to antibiotic susceptibility testing. Four nosocomial infections and 5 fight bites were excluded. RESULTS: Of the remaining 52 patients, 38 (73.1%) were MRSA positive. CONCLUSIONS: The rate of community-associated MRSA hand infections in an urban setting is higher than previously suspected. This should be taken into account when managing seemingly routine hand infections given that the treatment options are different for MRSA infections. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.     

Geographic distribution of community-acquired methicillin-resistant Staphylococcus aureus soft tissue infections

Purpose

The goal of this study is to look at the geographic growth patterns of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections in our local region and to determine if specific geographic areas are at increased risk.

Methods

After Institution Review Board approval (132603-3), a retrospective chart review was conducted of 614 patients who underwent incision and drainage of an abscess by a single pediatric surgical practice from January 2004 to December 2008. In addition, previously published data from 195 patients who underwent incision and drainage of an abscess from January 2000 to December 2003 were reviewed.

Results

The most commonly cultured organism found in the pediatric population undergoing incision and drainage was S aureus (n = 388), of which 258 (66%) were methicillin resistant. This is a 21% increase from the rate of MRSA cultures identified from 2000 to 2003. Geographic information system space-time analysis showed that a cluster of 14 MRSA cases was located within a 1.44-km radius between 2000 and 2003, and 5 separate clusters of more than 20 MRSA infection cases each were identified in 3 separate cities over the 8-year time span using geographic information system spatial analysis (P value = .001).

Conclusion

Methicillin-resistant S aureus has now become the most prevalent organism isolated from cultures of community-acquired abscesses requiring incision and drainage in the pediatric population in our local region. Significant clustering of MRSA infections has appeared in several different cities within our geographic region.     

Twenty years of countermeasures against postoperative methicillin-resistant Staphylococcus aureus infections

Purpose

A total of 7345 cases of digestive organ surgery were investigated over the course of 20 years.

Methods

Owing to the increasing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections, we classified our countermeasures into periods A (September 1987 to February 1990), B (March 1990 to February 1997), C (March 1997 to February 1999), D (March 1999 to October 2004), and E (November 2004 to August 2007), and compared the number of infections during these periods. In period B, cefazolin and cefotiam were administered as prophylaxes. The treatment continued for 4 days, including the day of surgery. The patients undergoing endotracheal intubation or tracheotomy were managed with nonscreening pre-emptive isolation and cohorting (NSPEI&;C), regardless of whether MRSA was present. However, NSPEI&;C was halted in period C, but it was thereafter implemented again, and prophylactic antibiotics were administered only on the day of surgery during period D. In period E, prophylactic antibiotics were administered for 3 days.

Results

In period A, MRSA was contracted in 4.1% (34/833) of patients. In period B, the MRSA isolation rate decreased to 0.3% (8/2722). In period C, the MRSA isolation rate increased to 3.4% (23/681). In period D, the MRSA isolation rate fell to 2.2% (40/1807). In period E, MRSA isolation cases significantly decreased to 0.4% (5/1302; P < 0.002 vs period D).

Conclusion

The comprehensive management, selection of prophylactic antibiotics, and NSPEI&;C were all considered to be effective.     

Methicillin-resistant Staphylococcus aureus osteomyelitis

In five patients, the diagnosis of methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis was made by clinical and roentgenographic methods and confirmed by bone biopsy cultures. The treatment was staged according to the anatomic setting of the infection and the systemic and local competence of the host. Seven episodes of osteomyelitis were encountered in the five patients. Two patients had persistence of their infection and were successfully treated by additional surgical debridement, antibiotics, and adjunctive hyperbaric oxygen. Vancomycin was administered to all patients. The daily dosage of vancomycin ranged between 100 mg and 2.0 gm. The length of vancomycin therapy ranged from 19 to 56 days. Five of seven biopsy specimens grew bacterial organisms in addition to MRSA. The MIC of vancomycin for MRSA ranged between 0.39 and 1.56 micrograms/ml. Osteomyelitis was arrested in five of seven episodes, and follow-up evaluations ranged from two to 35 months. Two of five (40%) patients receiving the combination of vancomycin and tobramycin developed signs of renal toxicity. Renal function returned to normal after discontinuation of the antibiotics. MRSA osteomyelitis is usually acquired by spread from a contiguous focus of infection and is often polymicrobic in nature. Treatment with vancomycin or vancomycin plus tobramycin when the infection was polymicrobic was effective. The combination of vancomycin plus tobramycin is potentially nephrotoxic.     

Biodegradable microspherical implants containing teicoplanin for the treatment of methicillin-resistant Staphylococcus aureus osteomyelitis

Background

The aim of this study was to prepare poly(d,l-lactide-co-glycolide) (PLGA) microspherical implants containing teicoplanin (TCP) using a double emulsion solvent evaporation method and to evaluate its efficacy for the local treatment of chronic osteomyelitis.

Methods

The particle size and distribution, morphological characteristics, thermal behaviour, drug content, encapsulation efficiency and in vitro release assessments of the formulations were carried out. Sterile TCP–PLGA microspheres were implanted in the proximal tibia of rats with methicillin resistant Staphylococcus aureus (MRSA) osteomyelitis. After 3 weeks of treatment, bone samples were analysed with a microbiological assay and evaluated histopathologically.

Results

Microspheres between the size ranges of 2.01 and 3.91 μm were obtained. Production yield of all formulations was found to be higher than 82% and encapsulation efficiencies of 33.6–69.8% were obtained. DSC thermogram showed that the TCP was in an amorphous state in microspheres. In vitro drug release studies had indicated that the drug release rate of microspheres was decreased upon increasing the polymer:drug ratio. Based on the in vivo data, rats treated with implants and intramuscular injection showed 1.7 × 10³ ± 1.3 × 10³ and 5.8 × 10⁴ ± 5.3 × 10⁴ colony forming unit of MRSA in 1 g bone samples (CFU/g), respectively (P < 0.01).

Conclusions

The in vitro and in vivo studies had shown that the TCP–PLGA microspheres were effective for the treatment of chronic osteomyelitis in an animal experimental model. Hence, these microspheres may be potentially useful in the clinical setting with the need for further investigation for optimal dosing of TCP–PLGA microspheres.     

Community-acquired methicillin-resistant Staphylococcus aureus: Review

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) have emerged worldwide. These CA-MRSA are different from classical hospital-acquired MRSA. They share common characteristics: they affect mainly young subjects, without past medical history. The majority of strains produce the Panton-Valentine leukocidin. They are mainly responsible for suppurative skin infections and rarely for invasive infections such as necrotizing pneumonia. The situation in the US is alarming with a main circulating clone the USA300 clone, whereas in Europe, the diffusion of CA-MRSA strains remains limited. It is important to take advantage of the experience acquired from the US to limit the potential spread of such CA-MRSA strains.     

Clinical outcomes of osteomyelitis patients infected with methicillin-resistant Staphylococcus aureus USA-300 strains

Methicillin-resistant Staphylococcus aureus (MRSA) USA-300 strains have emerged as an important cause of community-acquired infections. These strains have been recognized as an etiology of osteomyelitis but data on their incidence and outcomes are limited. We retrospectively studied the incidence and clinical outcomes of MRSA USA-300 osteomyelitis in patients at the University of Louisville Hospital and the Henry Ford Health System between January 2007 and March 2008. Pulsed-field gel electrophoresis was used to determine USA type. Clinical outcomes were defined as management success versus failure at 12 months. Chi-square tests, Fisher exact tests, and Mann-Whitney tests were used to compare patient characteristics on the basis of clinical outcomes and USA type. Of the 50 patients with MRSA osteomyelitis, 27 (54%) had the USA-300 strain. Clinical failure was identified in 22% (6/27) of the patients with MRSA USA-300 and in 30% (7/23) of the patients with MRSA non-USA-300 osteomyelitis (P = .509). Our results showed that MRSA USA-300 is a significant etiology of MRSA osteomyelitis. With current surgical and medical management, outcomes of patients with MRSA USA-300 osteomyelitis are similar to those of patients with MRSA non-USA-300 osteomyelitis.     

Vascularized fibular grafting in the treatment of methicillin-resistant Staphylococcus aureus osteomyelitis and infected nonunion

Twenty patients with methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis and bone infection were treated with vascularized fibular grafts. There were 16 males and four females, and the patient ages at operation ranged from 17 to 73 years. Nine of the lesions affected the femur, eight the tibia, and there were three others. All of the patients were treated with extensive debridement of the lesions and local antibiotic therapy. Continuous local irrigation was applied in two patients, antibiotic-formulated bone cement in five, and both in 10 patients. Recurrence of local infection occurred in six patients, including one failed graft. Eventually, 18 of the 20 cases attained successful subsidence of the inflammation. The mean period required to obtain radiographic bone union was 7 months in the femoral reconstruction group, 6.1 months in the tibial reconstruction group, and 6 months in the remaining patients. The authors believe that vascularized fibular grafting is the most reliable procedure for the treatment of MRSA osteomyelitis and infected nonunion.     

Acute rise in methicillin-resistant Staphylococcus aureus infections in a coastal community.

OBJECTIVE: Describe the incidence of head and neck community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections over a 5-year period at a coastal tertiary medical center. STUDY DESIGN: Retrospective chart review. SUBJECTS AND METHODS: All patients presenting to the otolaryngology service with cultures taken from head and neck infections between 1999 and 2004 were eligible for inclusion. Statistical analysis was used to determine significance of the changing incidence of isolated organisms over the study period. RESULTS: CA-MRSA infections rose from 21% to 64% over the 5-year period. The increasing trend in CA-MRSA infections reached statistical significance from 2003 to 2004. All CA-MRSA isolates were resistant to cefazolin and penicillin, but most were sensitive to clindamycin. CONCLUSIONS: Our data demonstrates a striking increase in the incidence of CA-MRSA. We have tailored our treatment of cutaneous head and neck infections to include empiric treatment for CA-MRSA using clindamycin. Awareness and monitoring of this trend will be important for all practitioners involved in the care of these patients.     

Community-acquired methicillin-resistant Staphylococcus aureus: a cause of musculoskeletal sepsis in children.

Between August 1996 and August 1997, 130 children were admitted to our pediatric orthopaedic unit with Staphylococcus aureus musculoskeletal infection. Twenty-six of the 130 staphylococcal isolates were resistant to methicillin, an incidence of 20%. All but one of the infections, a femoral fixator-pin infection, were community-acquired. Twenty-two of the infections were superficial; however, there were four cases of deep musculoskeletal sepsis due to methicillin-resistant S. aureus. In areas where methicillin-resistant S. aureus is prevalent in the community, methicillin resistance should be considered in any overwhelming staphylococcal infection not responding to conventional antibiotics despite adequate surgical debridement.