Faculty Bibliography

Preoperative screening and decolonization of methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA, respectively) are advocated to reduce surgical site infections. We determined the rate and duration of decolonization in patients undergoing elective orthopedic surgery. Patients undergoing elective orthopedic surgery were seen in our preoperative testing program (PAT) and had their anterior nares cultured for MRSA and MSSA. All patients were treated with intranasal mupirocin and a topical chlorhexidine solution. A cohort of patients returned to PAT before a subsequent elective procedure and were recultured. All culture results and time between PAT visits were recorded, and the rates of successful initial and persistent decolonization were determined. Six hundred ten patients visited PAT 1290 times. Overall, 94 (70.1%) of 134 patients with initially MRSA- or MSSA-positive cultures remained decolonized at a mean time of 156 days (SD=140), whereas 40 patients (29.9%) were not decolonized by the time of repeat testing at a mean time of 213 days (SD=187). At repeat testing, there were 2 newly MRSA-positive and 35 newly MSSA-positive patients. Staphylococcus aureus decolonization with intranasal mupirocin and topical chlorhexidine was effective but not persistent in a significant proportion of patients. A small number of previously uncolonized patients became colonized. Staphylococcus aureus screening and decolonization protocols must be repeated before any readmission, regardless of prior colonization status.

BACKGROUND AND OBJECTIVE: Chlorhexidine is recommended by several anesthesiology societies for antisepsis before regional anesthesia, but there is concern it may be neurotoxic. We evaluated the cytotoxicity of chlorhexidine and povidone-iodine in human neuronal and rat Schwann cells. METHODS: Human SH-SY5Y neuroblastoma and rat RSC96 Schwann cells were incubated with serial dilutions of 2% chlorhexidine gluconate and 10% povidone-iodine for 10 minutes, and viability was assessed with the MTT colorimetry assay and a fluorescent assay using calcein and ethidium. Cell morphology during antiseptic incubation was observed under light microscopy. To estimate the amount of antiseptic a needle carries through tissues, tritium radioactivity was measured in an animal injection model. RESULTS: Chlorhexidine at all tested concentrations significantly decreased viability compared with controls in both SH-SY5Y and RSC96 cells (P < 0.001). Povidone-iodine significantly decreased viability for both cells at concentrations of 0.2% or higher (P < 0.001). At the same dilutions of 1:200, 1:150, and 1:100, chlorhexidine was more cytotoxic than povidone-iodine for both cells (P< 0.001). During chlorhexidine treatment, both cell types became rounded and shriveled. Less dramatic changes were observed with povidone-iodine. In the injection model, 1.75% +/- 1.29% of the maximum amount of radioactive contamination was carried through tissues. CONCLUSIONS: Chlorhexidine gluconate and povidone-iodine were cytotoxic to SH-SY5Y (neuronal) and RSC96 (Schwann) cells. Chlorhexidine was more potent than povidone-iodine at more dilute concentrations. However, the toxicity of the two was not different at concentrations used clinically. When using either of these agents for antisepsis before regional anesthesia, it is prudent to allow adequate drying time after application.

We conducted a Markov decision analysis to assess the cost savings associated with a preoperative Staphylococcus aureus screening and decolonization program on 365 hip and knee arthroplasties and 287 spine fusions. A 2-way sensitivity analysis was also used to calculate the needed reduction in surgical site infections to make the program cost saving. If cost of treating an infected hip or knee arthroplasty is equal to the cost of a primary knee arthroplasty, then the screening program needs to result in a 35% reduction in the revision rate, or a relative revision rate of 65% for patients in the screening program, to be cost saving. For spine fusions, the reduction in the revision rate to make the program cost saving is only 10%. Universal Staphylococcus aureus screening and decolonization for hip and knee arthroplasty and spinal fusion patients needs to result in only a modest reduction in the surgical site infection rate to be cost saving

Klebsiella pneumoniae carbapenemase (KPC)-producing bacteria are a group of emerging highly drug-resistant Gram-negative bacilli causing infections associated with significant morbidity and mortality. Once confined to outbreaks in the northeastern United States (US), they have spread throughout the US and most of the world. KPCs are an important mechanism of resistance for an increasingly wide range of Gram-negative bacteria and are no longer limited to K pneumoniae. KPC-producing bacteria are often misidentified by routine microbiological susceptibility testing and incorrectly reported as sensitive to carbapenems; however, resistance to the carbapenem antibiotic ertapenem is common and a better indicator of the presence of KPCs. Carbapenem antibiotics are generally not effective against KPC-producing organisms. The best therapeutic approach to KPC-producing organisms has yet to be defined; however, common treatments based on in vitro susceptibility testing are the polymyxins, tigecycline, and less frequently, aminoglycoside antibiotics. The purpose of this review is to identify the various challenges that KPC-producing bacteria present to clinicians. These include the need for special techniques for microbiological detection, the potential for nosocomial transmission, and therapeutic challenges related to limited, relatively unproven antimicrobial treatment options

BACKGROUND: Although the effect of Staphylococcus aureus (SA) decolonization on surgical site infection (SSI) rates has been studied, patient tolerance and acceptance of these regimens has not been assessed. Surgical patients at our hospital's Pre-Admission Testing Clinic (PAT) receive SA reduction protocols instructing the preoperative use of chlorhexidine gluconate (CHG) soap and intranasal mupirocin ointment (MO). Certain insurers do not cover MO costs resulting in out of pocket (OOP) expenses for some patients. OBJECTIVE: This study assessed patient attitudes and compliance with our hospital's SA decolonization regimen. METHODS: One-hundred-forty-six patients received surveys. Descriptive statistics were used for analysis. RESULTS: Of respondents fitting inclusion criteria, 81% followed the MO protocol (MO users) while 89% followed the CHG protocol (CHG users). Fifty-four percent of MO users reported OOP expenses and 13% reported a hard or very hard financial burden. Ninety-three percent of CHG users reported the protocol was easy or very easy to follow. CONCLUSION: Eighty-one percent of patients receiving the SA protocol were fully compliant despite cost or difficulty obtaining MO. Given these barriers and some difficulty with CHG application, we hypothesize compliance may be improved if MO is provided to patients without OOP expenses and if the CHG application method is simplified.

We examined New York City Department of Health and Mental Hygiene surveillance data on hepatitis A, malaria, and typhoid to determine the proportion of these diseases related to travel and their geographic distribution. We found that 61% of hepatitis A cases, 100% of malaria cases, and 78% of typhoid cases were travel related and that cases clustered in specific populations and neighborhoods at which public health interventions could be targeted. High-risk groups include Hispanics (for hepatitis A), West Africans living in the Bronx (for malaria), and South Asians (for typhoid)

In Pennsylvania on February 16, 2006, a New York City resident collapsed with rigors and was hospitalized. On February 21, the Centers for Disease Control and Prevention and the New York City Department of Health and Mental Hygiene were notified that Bacillus anthracis had been identified in the patient's blood. Although the patient's history of working with dried animal hides to make African drums indicated the likelihood of a natural exposure to aerosolized anthrax spores, bioterrorism had to be ruled out first. Ultimately, this case proved to be the first case of naturally occurring inhalational anthrax in 30 years. This article describes the epidemiologic and environmental investigation to identify other cases and persons at risk and to determine the source of exposure and scope of contamination. Because stricter regulation of the importation of animal hides from areas where anthrax is enzootic is difficult, public healthcare officials should consider the possibility of future naturally occurring anthrax cases caused by contaminated hides. Federal protocols are needed to assist in the local response, which should be tempered by our growing understanding of the epidemiology of naturally acquired anthrax. These protocols should include recommended methods for reliable and efficient environmental sample collection and laboratory testing, and environmental risk assessments and remediation.