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Interscience Conference on Antimicrobial Agents & Chemotherapy (ICAAC)/ International Congress of Chemotherapy (ICC)
Underweight patients showed greater mortality with gram-negative bacteremia
SAN DIEGO – Patients hospitalized for gram-negative bacteremia who weighed more than 70 kg had improved 30-day mortality, compared with those who weighed 70 kg or less, results from a single-center study showed.
“This study is a first step to determine the impact of low body weight on mortality in patients with bloodstream infections due to gram negative pathogens,” Ronald G. Hall II, Pharm.D., MSCS, said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “It should reinforce that clinicians need to aggressively treat patients who weigh less than 70 kg due to the increased risk of death. However, more data are needed to confirm this finding and determine the causes of this association.”
For the study, Dr. Hall, of the Texas Tech University Health Sciences Center School of Pharmacy, Dallas, and his associates retrospectively evaluated 324 patients admitted to a community teaching hospital for gram-negative bacteremia who received at least two days of empiric antibiotic therapy. They used univariate and multivariable logistic regression analysis to compare the 30-day mortality of patients with a total body weight of 70 kg or less with those weighing more than 70 kg.
Of the 324 patients, 184 (57%) weighed more than 70 kg. The 30-day mortality rate was 16.3% for patients who weighed 70 kg or less, compared with 10.5% for their counterparts who weighed more than 70 kg. This difference did not reach statistical significance on univariate analysis (odds ratio 0.67 for the higher body weight patients), but it did reach statistical significance on multivariable analysis (OR .43 for the higher body weight patients). Other factors that remained significant in the multivariable model were a cancer diagnosis (OR 2.55) and a Pitt bacteremia score of 4 or greater (OR 16.83).
“This study is the first, to our knowledge, to evaluate the impact of low total body weight on mortality in patients with bloodstream infections due to gram-negative pathogens,” Dr. Hall said. “Other investigators have found similar results previously evaluating the impact of underweight patients using body mass index (BMI). However, BMI uses both height and weight, with height being taken into a greater account (kg/m2) which may be misleading on the impact of weight.”
He acknowledged certain limitations of the study, including its single-center design. “A larger cohort will help improve our confidence in this finding by being able to control for more potential confounding variables,” he said.
Dr. Hall disclosed that he is a scientific advisor for Genentech. The other researchers reported having no financial disclosures.
SAN DIEGO – Patients hospitalized for gram-negative bacteremia who weighed more than 70 kg had improved 30-day mortality, compared with those who weighed 70 kg or less, results from a single-center study showed.
“This study is a first step to determine the impact of low body weight on mortality in patients with bloodstream infections due to gram negative pathogens,” Ronald G. Hall II, Pharm.D., MSCS, said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “It should reinforce that clinicians need to aggressively treat patients who weigh less than 70 kg due to the increased risk of death. However, more data are needed to confirm this finding and determine the causes of this association.”
For the study, Dr. Hall, of the Texas Tech University Health Sciences Center School of Pharmacy, Dallas, and his associates retrospectively evaluated 324 patients admitted to a community teaching hospital for gram-negative bacteremia who received at least two days of empiric antibiotic therapy. They used univariate and multivariable logistic regression analysis to compare the 30-day mortality of patients with a total body weight of 70 kg or less with those weighing more than 70 kg.
Of the 324 patients, 184 (57%) weighed more than 70 kg. The 30-day mortality rate was 16.3% for patients who weighed 70 kg or less, compared with 10.5% for their counterparts who weighed more than 70 kg. This difference did not reach statistical significance on univariate analysis (odds ratio 0.67 for the higher body weight patients), but it did reach statistical significance on multivariable analysis (OR .43 for the higher body weight patients). Other factors that remained significant in the multivariable model were a cancer diagnosis (OR 2.55) and a Pitt bacteremia score of 4 or greater (OR 16.83).
“This study is the first, to our knowledge, to evaluate the impact of low total body weight on mortality in patients with bloodstream infections due to gram-negative pathogens,” Dr. Hall said. “Other investigators have found similar results previously evaluating the impact of underweight patients using body mass index (BMI). However, BMI uses both height and weight, with height being taken into a greater account (kg/m2) which may be misleading on the impact of weight.”
He acknowledged certain limitations of the study, including its single-center design. “A larger cohort will help improve our confidence in this finding by being able to control for more potential confounding variables,” he said.
Dr. Hall disclosed that he is a scientific advisor for Genentech. The other researchers reported having no financial disclosures.
SAN DIEGO – Patients hospitalized for gram-negative bacteremia who weighed more than 70 kg had improved 30-day mortality, compared with those who weighed 70 kg or less, results from a single-center study showed.
“This study is a first step to determine the impact of low body weight on mortality in patients with bloodstream infections due to gram negative pathogens,” Ronald G. Hall II, Pharm.D., MSCS, said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “It should reinforce that clinicians need to aggressively treat patients who weigh less than 70 kg due to the increased risk of death. However, more data are needed to confirm this finding and determine the causes of this association.”
For the study, Dr. Hall, of the Texas Tech University Health Sciences Center School of Pharmacy, Dallas, and his associates retrospectively evaluated 324 patients admitted to a community teaching hospital for gram-negative bacteremia who received at least two days of empiric antibiotic therapy. They used univariate and multivariable logistic regression analysis to compare the 30-day mortality of patients with a total body weight of 70 kg or less with those weighing more than 70 kg.
Of the 324 patients, 184 (57%) weighed more than 70 kg. The 30-day mortality rate was 16.3% for patients who weighed 70 kg or less, compared with 10.5% for their counterparts who weighed more than 70 kg. This difference did not reach statistical significance on univariate analysis (odds ratio 0.67 for the higher body weight patients), but it did reach statistical significance on multivariable analysis (OR .43 for the higher body weight patients). Other factors that remained significant in the multivariable model were a cancer diagnosis (OR 2.55) and a Pitt bacteremia score of 4 or greater (OR 16.83).
“This study is the first, to our knowledge, to evaluate the impact of low total body weight on mortality in patients with bloodstream infections due to gram-negative pathogens,” Dr. Hall said. “Other investigators have found similar results previously evaluating the impact of underweight patients using body mass index (BMI). However, BMI uses both height and weight, with height being taken into a greater account (kg/m2) which may be misleading on the impact of weight.”
He acknowledged certain limitations of the study, including its single-center design. “A larger cohort will help improve our confidence in this finding by being able to control for more potential confounding variables,” he said.
Dr. Hall disclosed that he is a scientific advisor for Genentech. The other researchers reported having no financial disclosures.
AT ICAAC 2015
Key clinical point: Increased patient weight impacts 30-day mortality in cases of gram-negative bacteremia.
Major finding: The 30-day mortality rate was 11% for patients who weighed more than 70 kg, compared with 16% for their counterparts who weighed 70 kg or less.
Data source: A retrospective cohort study of 324 patients admitted to a community teaching hospital for gram-negative bacteremia who received at least two days of empiric antibiotic therapy.
Disclosures: Dr. Hall disclosed that he is a scientific advisor for Genentech. The other researchers reported having no financial disclosures.
Cefazolin outperforms nafcillin for staphylococcal bacteremia
SAN DIEGO – Cefazolin is more effective, less toxic, easier to dose, and far less expensive than nafcillin; the current guideline-recommended first-line standard therapy for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, Marguerite L. Monogue, Pharm.D., reported at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
“These findings, coupled with the cost savings involved with using cefazolin over nafcillin, make it an appealing first-line agent for most MSSA bloodstream infections,” asserted Dr. Monogue of Hartford (Conn.) Hospital.
She presented a retrospective, nonrandomized cohort study involving 142 patients admitted to Parkland Hospital in Dallas for treatment of MSSA bacteremia due to endocarditis, osteomyelitis, pneumonia, or deep abscesses. Half started on nafcillin, the other half on cefazolin.
The treatment failure rate was 8.4% in the cefazolin group compared with 14% in the nafcillin-treated patients.
Moreover, the adverse event rate was 7% with cefazolin versus 19.7% with nafcillin. Nephrotoxicity was the main side effect; it occurred in 16.9% of the nafcillin group compared with 2.8% of those on cefazolin.
These study results are sure to draw the attention of hospital administrators because nafcillin costs a hefty 10-13 times more than cefazolin. Dr. Monogue estimated that Parkland Hospital would have saved nearly $100,000 if the 71 nafcillin-treated patients had instead received cefazolin.
“Some of these endocarditis and osteomyelitis patients are being treated for 6 weeks,” she noted.
Both drugs are beta-lactam antimicrobials. Their mechanisms of action are similar. However, nafcillin is classified as a penicillin, while cefazolin is considered a first-generation cephalosporin.
Nafcillin is dosed every 4 hours or by continuous infusion. Cefazolin is dosed once every 8 hours. Advantage cefazoline. Another dosing advantage favoring cefazolin is that at Parkland Hospital, patients can be discharged on cefazaolin and complete their treatment course at home, while if they’re on nafcillin they must remain in-hospital to finish their regimen.
Dr. Monogue reported having no financial conflicts with regard to this investigator-initiated, unfunded study.
SAN DIEGO – Cefazolin is more effective, less toxic, easier to dose, and far less expensive than nafcillin; the current guideline-recommended first-line standard therapy for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, Marguerite L. Monogue, Pharm.D., reported at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
“These findings, coupled with the cost savings involved with using cefazolin over nafcillin, make it an appealing first-line agent for most MSSA bloodstream infections,” asserted Dr. Monogue of Hartford (Conn.) Hospital.
She presented a retrospective, nonrandomized cohort study involving 142 patients admitted to Parkland Hospital in Dallas for treatment of MSSA bacteremia due to endocarditis, osteomyelitis, pneumonia, or deep abscesses. Half started on nafcillin, the other half on cefazolin.
The treatment failure rate was 8.4% in the cefazolin group compared with 14% in the nafcillin-treated patients.
Moreover, the adverse event rate was 7% with cefazolin versus 19.7% with nafcillin. Nephrotoxicity was the main side effect; it occurred in 16.9% of the nafcillin group compared with 2.8% of those on cefazolin.
These study results are sure to draw the attention of hospital administrators because nafcillin costs a hefty 10-13 times more than cefazolin. Dr. Monogue estimated that Parkland Hospital would have saved nearly $100,000 if the 71 nafcillin-treated patients had instead received cefazolin.
“Some of these endocarditis and osteomyelitis patients are being treated for 6 weeks,” she noted.
Both drugs are beta-lactam antimicrobials. Their mechanisms of action are similar. However, nafcillin is classified as a penicillin, while cefazolin is considered a first-generation cephalosporin.
Nafcillin is dosed every 4 hours or by continuous infusion. Cefazolin is dosed once every 8 hours. Advantage cefazoline. Another dosing advantage favoring cefazolin is that at Parkland Hospital, patients can be discharged on cefazaolin and complete their treatment course at home, while if they’re on nafcillin they must remain in-hospital to finish their regimen.
Dr. Monogue reported having no financial conflicts with regard to this investigator-initiated, unfunded study.
SAN DIEGO – Cefazolin is more effective, less toxic, easier to dose, and far less expensive than nafcillin; the current guideline-recommended first-line standard therapy for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, Marguerite L. Monogue, Pharm.D., reported at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
“These findings, coupled with the cost savings involved with using cefazolin over nafcillin, make it an appealing first-line agent for most MSSA bloodstream infections,” asserted Dr. Monogue of Hartford (Conn.) Hospital.
She presented a retrospective, nonrandomized cohort study involving 142 patients admitted to Parkland Hospital in Dallas for treatment of MSSA bacteremia due to endocarditis, osteomyelitis, pneumonia, or deep abscesses. Half started on nafcillin, the other half on cefazolin.
The treatment failure rate was 8.4% in the cefazolin group compared with 14% in the nafcillin-treated patients.
Moreover, the adverse event rate was 7% with cefazolin versus 19.7% with nafcillin. Nephrotoxicity was the main side effect; it occurred in 16.9% of the nafcillin group compared with 2.8% of those on cefazolin.
These study results are sure to draw the attention of hospital administrators because nafcillin costs a hefty 10-13 times more than cefazolin. Dr. Monogue estimated that Parkland Hospital would have saved nearly $100,000 if the 71 nafcillin-treated patients had instead received cefazolin.
“Some of these endocarditis and osteomyelitis patients are being treated for 6 weeks,” she noted.
Both drugs are beta-lactam antimicrobials. Their mechanisms of action are similar. However, nafcillin is classified as a penicillin, while cefazolin is considered a first-generation cephalosporin.
Nafcillin is dosed every 4 hours or by continuous infusion. Cefazolin is dosed once every 8 hours. Advantage cefazoline. Another dosing advantage favoring cefazolin is that at Parkland Hospital, patients can be discharged on cefazaolin and complete their treatment course at home, while if they’re on nafcillin they must remain in-hospital to finish their regimen.
Dr. Monogue reported having no financial conflicts with regard to this investigator-initiated, unfunded study.
AT ICAAC 2015
Key clinical point: The time is nigh for cefazolin to replace nafcillin as first-line therapy for methicillin-susceptible Staphylococcus aureus bacteremia.
Major finding: Treatment failure and adverse event rates were 8.4% and 7%, respectively, with cefazolin, compared with 14% and 19.7% with nafcillin.
Data source: This retrospective, nonrandomized cohort study included 142 patients hospitalized for methicillin-suscueptible Staphylococcus aureus bacteremia, with half started on current first-line nafcillin, the other half on cefazolin.
Disclosures: The presenter reported having no financial conflicts with regard to this investigator-initiated, unfunded study.
Prolonged sepsis increased inpatient mortality risk
SAN DIEGO – The longer patients have sepsis, the more likely they are to die while in the hospital, a retrospective, single-center study showed.
However, lower respiratory tract infection, methicillin-resistant Staphylococcus aureus infection, Charlson score, and time to first antibiotic dose were not significantly associated with increased odds for mortality.
“Sepsis is a life-threatening acute condition that is commonly associated with inpatient mortality,” lead study author Joseph J. Carreno, Pharm.D., said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “To date, numerous interventions have evaluated the impact of interventions on sepsis-related mortality. However, few have examined duration of sepsis as a predictor of mortality.”
An earlier analysis conducted by Dr. Carreno and his associates at the Albany (N.Y.) College of Pharmacy and Health Sciences found that the duration of sepsis may be reduced through the use of multimodal interventions implemented by interdisciplinary teams.
For the current study, the researchers set out to evaluate the relationship between time to sepsis resolution and inpatient mortality by reviewing the records of 248 patients with documented sepsis who received antimicrobial therapy at Albany Medical Center Hospital. They defined time to sepsis resolution as time in days from blood culture to first date with fewer than two signs of systemic inflammatory response syndrome.
The mean age of the patients was 63 years, 67% were male, and 31% initially were admitted to the intensive care unit. The most prevalent sources of infection were genitourinary (24%), lower respiratory tract (17%), and endovascular (17%), while the most prevalent organisms isolated were coagulase-negative Staphylococcus (20%), Escherichia coli (18%), Streptococcus (15%), and methicillin-sensitive S. aureus (8%).
In all, 21 patients (9%) died. On multivariable analysis, the only significant risk factors for inpatient mortality were time (in days) to sepsis resolution (odds ratio, 1.13) and being initially admitted to the ICU (OR, 5.21).
“What was most surprising to me was the steady increase in mortality that was seen with each day of unresolved sepsis,” Dr. Carreno commented. “We hypothesized that there would be an association between time to sepsis resolution and mortality, but we thought that there would be a natural cut point rather than a steady increase in risk.”
Others factors such as lower respiratory tract infection, Charlson score, methicillin-resistant S. aureus infection, and time to first antibiotic dose didn’t have a significant association with increased odds for mortality.
“In our study, prolonged duration of sepsis was an early predictor of inpatient mortality,” he concluded. “Hence, patients’ response to therapy should be evaluated early in therapy. Our study supports recommendations from the Food and Drug Administration’s new guidance for clinical trials and the Centers for Disease Control and Prevention’s antibiotic ‘time out’ concept.”
Dr. Carreno reported having no financial disclosures.
SAN DIEGO – The longer patients have sepsis, the more likely they are to die while in the hospital, a retrospective, single-center study showed.
However, lower respiratory tract infection, methicillin-resistant Staphylococcus aureus infection, Charlson score, and time to first antibiotic dose were not significantly associated with increased odds for mortality.
“Sepsis is a life-threatening acute condition that is commonly associated with inpatient mortality,” lead study author Joseph J. Carreno, Pharm.D., said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “To date, numerous interventions have evaluated the impact of interventions on sepsis-related mortality. However, few have examined duration of sepsis as a predictor of mortality.”
An earlier analysis conducted by Dr. Carreno and his associates at the Albany (N.Y.) College of Pharmacy and Health Sciences found that the duration of sepsis may be reduced through the use of multimodal interventions implemented by interdisciplinary teams.
For the current study, the researchers set out to evaluate the relationship between time to sepsis resolution and inpatient mortality by reviewing the records of 248 patients with documented sepsis who received antimicrobial therapy at Albany Medical Center Hospital. They defined time to sepsis resolution as time in days from blood culture to first date with fewer than two signs of systemic inflammatory response syndrome.
The mean age of the patients was 63 years, 67% were male, and 31% initially were admitted to the intensive care unit. The most prevalent sources of infection were genitourinary (24%), lower respiratory tract (17%), and endovascular (17%), while the most prevalent organisms isolated were coagulase-negative Staphylococcus (20%), Escherichia coli (18%), Streptococcus (15%), and methicillin-sensitive S. aureus (8%).
In all, 21 patients (9%) died. On multivariable analysis, the only significant risk factors for inpatient mortality were time (in days) to sepsis resolution (odds ratio, 1.13) and being initially admitted to the ICU (OR, 5.21).
“What was most surprising to me was the steady increase in mortality that was seen with each day of unresolved sepsis,” Dr. Carreno commented. “We hypothesized that there would be an association between time to sepsis resolution and mortality, but we thought that there would be a natural cut point rather than a steady increase in risk.”
Others factors such as lower respiratory tract infection, Charlson score, methicillin-resistant S. aureus infection, and time to first antibiotic dose didn’t have a significant association with increased odds for mortality.
“In our study, prolonged duration of sepsis was an early predictor of inpatient mortality,” he concluded. “Hence, patients’ response to therapy should be evaluated early in therapy. Our study supports recommendations from the Food and Drug Administration’s new guidance for clinical trials and the Centers for Disease Control and Prevention’s antibiotic ‘time out’ concept.”
Dr. Carreno reported having no financial disclosures.
SAN DIEGO – The longer patients have sepsis, the more likely they are to die while in the hospital, a retrospective, single-center study showed.
However, lower respiratory tract infection, methicillin-resistant Staphylococcus aureus infection, Charlson score, and time to first antibiotic dose were not significantly associated with increased odds for mortality.
“Sepsis is a life-threatening acute condition that is commonly associated with inpatient mortality,” lead study author Joseph J. Carreno, Pharm.D., said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “To date, numerous interventions have evaluated the impact of interventions on sepsis-related mortality. However, few have examined duration of sepsis as a predictor of mortality.”
An earlier analysis conducted by Dr. Carreno and his associates at the Albany (N.Y.) College of Pharmacy and Health Sciences found that the duration of sepsis may be reduced through the use of multimodal interventions implemented by interdisciplinary teams.
For the current study, the researchers set out to evaluate the relationship between time to sepsis resolution and inpatient mortality by reviewing the records of 248 patients with documented sepsis who received antimicrobial therapy at Albany Medical Center Hospital. They defined time to sepsis resolution as time in days from blood culture to first date with fewer than two signs of systemic inflammatory response syndrome.
The mean age of the patients was 63 years, 67% were male, and 31% initially were admitted to the intensive care unit. The most prevalent sources of infection were genitourinary (24%), lower respiratory tract (17%), and endovascular (17%), while the most prevalent organisms isolated were coagulase-negative Staphylococcus (20%), Escherichia coli (18%), Streptococcus (15%), and methicillin-sensitive S. aureus (8%).
In all, 21 patients (9%) died. On multivariable analysis, the only significant risk factors for inpatient mortality were time (in days) to sepsis resolution (odds ratio, 1.13) and being initially admitted to the ICU (OR, 5.21).
“What was most surprising to me was the steady increase in mortality that was seen with each day of unresolved sepsis,” Dr. Carreno commented. “We hypothesized that there would be an association between time to sepsis resolution and mortality, but we thought that there would be a natural cut point rather than a steady increase in risk.”
Others factors such as lower respiratory tract infection, Charlson score, methicillin-resistant S. aureus infection, and time to first antibiotic dose didn’t have a significant association with increased odds for mortality.
“In our study, prolonged duration of sepsis was an early predictor of inpatient mortality,” he concluded. “Hence, patients’ response to therapy should be evaluated early in therapy. Our study supports recommendations from the Food and Drug Administration’s new guidance for clinical trials and the Centers for Disease Control and Prevention’s antibiotic ‘time out’ concept.”
Dr. Carreno reported having no financial disclosures.
AT ICAAC 2015
Key clinical point: Prolonged duration of sepsis is an early predictor of inpatient mortality.
Major finding: Significant risk factors for inpatient mortality were time (in days) to sepsis resolution (OR, 1.13) and being initially admitted to the ICU (OR, 5.21).
Data source: A retrospective case-control study of 248 patients at Albany (N.Y.) Medical Center Hospital with documented sepsis who received antimicrobial therapy.
Disclosures: Dr. Carreno reported having no financial disclosures.
Smoother orthopedic implants may minimize bacterial adherence
SAN DIEGO – Rough materials used for orthopedic implants, such as cobalt chromium and titanium, increased bacterial adherence, while smoother materials such as stainless steel did not, results from an image analysis demonstrated.
“In light of these results, it is important to question why we utilize the types of materials we use for various orthopedic procedures,” Dioscaris R. Garcia, Ph.D., said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “There was no one-size-fits-all material to minimize adherence per the findings of this study, but the findings may suggest that having a smoother surface may minimize the ability of bacterial pathogens to adhere to the surface.”
He characterized the topic of bacterial adherence to orthopedic implants as “an issue of great interest due to how little is known about the biological implications of the materials utilized. The most researched of these materials is titanium, which is touted for its biocompatibility. This study aims to provide a base and a glimpse into how the most commonly utilized orthopedic-relevant materials interact with some of the most commonly encountered pathogens.”
For the study, Dr. Garcia, a molecular pharmacologist at Rhode Island Hospital in Providence, Dr. Alan H. Daniels, an orthopedic surgeon at the hospital, and their associates used scanning electron microscopy and confocal laser scanning microscopy to evaluate the adherence pattern, density, and propagation of six commonly encountered bacterial pathogens (methicillin-sensitive Staphylococcus aureus, methicillin-resistant S. aureus, coagulase-negative Staphylococcus epidermidis, multidrug-resistant Acinetobacter baumannii, Propionibacterium acnes, and vancomycin-resistant Enterococcus faecalis) on five commonly used spinal implant materials (titanium, titanium alloy, stainless steel, cobalt chromium, and polyetherether ketone). The samples were fixed and dehydrated via ethanol dehydration gradient and critical point drying.
The researchers found that some pathogens, such as vancomycin-resistant E. faecalis and multidrug-resistant A. baumannii, were more likely to adhere to more textured materials such as cobalt chromium and titanium, compared with smoother materials such as stainless steel. “Additionally, the findings suggest that the microtopography of these materials may be the driving force behind the adherence of pathogens on the materials themselves,” Dr. Garcia said. Compared with smoother, polished materials, he explained, the rougher materials were more likely to harbor dense proliferation of bacterial pathogens, which could be characterized as biofilms.
“This study has been successful in providing a platform for future studies to build upon and expand to study additional parameters and statistical tools to give further insight into additional driving forces behind adherence and means for improvement of material design,” Dr. Garcia concluded.
Dr. Christopher T. Born, head of the Diane N. Weiss Center for Orthopedic Trauma Research at Rhode Island Hospital, was the study’s principal investigator. The study was supported by Stryker Corp.*
*Correction, 9/19/2015: Dr. Born is a consultant for Stryker. He also has stock ownership in Biointraface, does consulting for the company, and is a member of its board.
SAN DIEGO – Rough materials used for orthopedic implants, such as cobalt chromium and titanium, increased bacterial adherence, while smoother materials such as stainless steel did not, results from an image analysis demonstrated.
“In light of these results, it is important to question why we utilize the types of materials we use for various orthopedic procedures,” Dioscaris R. Garcia, Ph.D., said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “There was no one-size-fits-all material to minimize adherence per the findings of this study, but the findings may suggest that having a smoother surface may minimize the ability of bacterial pathogens to adhere to the surface.”
He characterized the topic of bacterial adherence to orthopedic implants as “an issue of great interest due to how little is known about the biological implications of the materials utilized. The most researched of these materials is titanium, which is touted for its biocompatibility. This study aims to provide a base and a glimpse into how the most commonly utilized orthopedic-relevant materials interact with some of the most commonly encountered pathogens.”
For the study, Dr. Garcia, a molecular pharmacologist at Rhode Island Hospital in Providence, Dr. Alan H. Daniels, an orthopedic surgeon at the hospital, and their associates used scanning electron microscopy and confocal laser scanning microscopy to evaluate the adherence pattern, density, and propagation of six commonly encountered bacterial pathogens (methicillin-sensitive Staphylococcus aureus, methicillin-resistant S. aureus, coagulase-negative Staphylococcus epidermidis, multidrug-resistant Acinetobacter baumannii, Propionibacterium acnes, and vancomycin-resistant Enterococcus faecalis) on five commonly used spinal implant materials (titanium, titanium alloy, stainless steel, cobalt chromium, and polyetherether ketone). The samples were fixed and dehydrated via ethanol dehydration gradient and critical point drying.
The researchers found that some pathogens, such as vancomycin-resistant E. faecalis and multidrug-resistant A. baumannii, were more likely to adhere to more textured materials such as cobalt chromium and titanium, compared with smoother materials such as stainless steel. “Additionally, the findings suggest that the microtopography of these materials may be the driving force behind the adherence of pathogens on the materials themselves,” Dr. Garcia said. Compared with smoother, polished materials, he explained, the rougher materials were more likely to harbor dense proliferation of bacterial pathogens, which could be characterized as biofilms.
“This study has been successful in providing a platform for future studies to build upon and expand to study additional parameters and statistical tools to give further insight into additional driving forces behind adherence and means for improvement of material design,” Dr. Garcia concluded.
Dr. Christopher T. Born, head of the Diane N. Weiss Center for Orthopedic Trauma Research at Rhode Island Hospital, was the study’s principal investigator. The study was supported by Stryker Corp.*
*Correction, 9/19/2015: Dr. Born is a consultant for Stryker. He also has stock ownership in Biointraface, does consulting for the company, and is a member of its board.
SAN DIEGO – Rough materials used for orthopedic implants, such as cobalt chromium and titanium, increased bacterial adherence, while smoother materials such as stainless steel did not, results from an image analysis demonstrated.
“In light of these results, it is important to question why we utilize the types of materials we use for various orthopedic procedures,” Dioscaris R. Garcia, Ph.D., said in an interview in advance of the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. “There was no one-size-fits-all material to minimize adherence per the findings of this study, but the findings may suggest that having a smoother surface may minimize the ability of bacterial pathogens to adhere to the surface.”
He characterized the topic of bacterial adherence to orthopedic implants as “an issue of great interest due to how little is known about the biological implications of the materials utilized. The most researched of these materials is titanium, which is touted for its biocompatibility. This study aims to provide a base and a glimpse into how the most commonly utilized orthopedic-relevant materials interact with some of the most commonly encountered pathogens.”
For the study, Dr. Garcia, a molecular pharmacologist at Rhode Island Hospital in Providence, Dr. Alan H. Daniels, an orthopedic surgeon at the hospital, and their associates used scanning electron microscopy and confocal laser scanning microscopy to evaluate the adherence pattern, density, and propagation of six commonly encountered bacterial pathogens (methicillin-sensitive Staphylococcus aureus, methicillin-resistant S. aureus, coagulase-negative Staphylococcus epidermidis, multidrug-resistant Acinetobacter baumannii, Propionibacterium acnes, and vancomycin-resistant Enterococcus faecalis) on five commonly used spinal implant materials (titanium, titanium alloy, stainless steel, cobalt chromium, and polyetherether ketone). The samples were fixed and dehydrated via ethanol dehydration gradient and critical point drying.
The researchers found that some pathogens, such as vancomycin-resistant E. faecalis and multidrug-resistant A. baumannii, were more likely to adhere to more textured materials such as cobalt chromium and titanium, compared with smoother materials such as stainless steel. “Additionally, the findings suggest that the microtopography of these materials may be the driving force behind the adherence of pathogens on the materials themselves,” Dr. Garcia said. Compared with smoother, polished materials, he explained, the rougher materials were more likely to harbor dense proliferation of bacterial pathogens, which could be characterized as biofilms.
“This study has been successful in providing a platform for future studies to build upon and expand to study additional parameters and statistical tools to give further insight into additional driving forces behind adherence and means for improvement of material design,” Dr. Garcia concluded.
Dr. Christopher T. Born, head of the Diane N. Weiss Center for Orthopedic Trauma Research at Rhode Island Hospital, was the study’s principal investigator. The study was supported by Stryker Corp.*
*Correction, 9/19/2015: Dr. Born is a consultant for Stryker. He also has stock ownership in Biointraface, does consulting for the company, and is a member of its board.
AT ICAAC 2015
Key clinical point: Orthopedic implants made from smoother material may minimize bacterial adherence.
Major finding: Some pathogens, such as vancomycin-resistant Enterococcus faecalis and multidrug-resistant Acinetobacter baumannii, were more likely to adhere to more textured materials like cobalt chromium and titanium, compared with smoother materials such as stainless steel.
Data source: A study that used scanning electron microscopy and confocal laser scanning microscopy to evaluate the adherence pattern, density, and propagation of six commonly encountered bacterial pathogens on five commonly used spinal implant materials.
Disclosures: The study was supported by Stryker Corp. Dr. Born is a consultant for Stryker. He also has stock ownership in Biointraface, does consulting for the company, and is a member of its board.*
