A role for arthropods as vectors of multidrug-resistant Enterobacterales in surgical site infections from South Asia.

Understanding how multidrug-resistant Enterobacterales (MDRE) are transmitted in low- and middle-income countries (LMICs) is critical for implementing robust policies to curb the increasing burden of antimicrobial resistance (AMR). Here, we analysed samples from surgical site infections (SSIs), hospital surfaces (HSs) and arthropods (summer and winter 2016) to investigate the incidence and transmission of MDRE in a public hospital in Pakistan. We investigated Enterobacterales containing resistance genes (blaCTX-M-15, blaNDM and blaOXA-48-like) for identification, antimicrobial susceptibility testing and whole-genome sequencing. Genotypes, phylogenetic relationships and transmission events for isolates from different sources were investigated using single-nucleotide polymorphism (SNP) analysis with a cut-off of ≤20 SNPs. Escherichia coli (14.3%), Klebsiella pneumoniae (10.9%) and Enterobacter cloacae (16.3%) were the main MDRE species isolated. The carbapenemase gene blaNDM was most commonly detected, with 15.5%, 15.1% and 13.3% of samples positive in SSIs, HSs and arthropods, respectively. SNP (≤20) and spatiotemporal analysis revealed linkages in bacteria between SSIs, HSs and arthropods supporting the One Health approach to underpin infection control policies across LMICs and control AMR.

Aerosol generation through pars plana vitrectomy.

PURPOSE: To assess whether pars plana vitrectomy (PPV) is an aerosol-generating procedure (AGP) in an ex vivo experimental model. METHODS: In this ex vivo study on 10 porcine eyes, optical particle counter was used to measure particles ≤10 µm using cumulative mode in the six in-built channels: 0.3 µm, 0.5 µm, 1 µm, 2.5 µm, 5 µm and 10 µm aerosols during PPV. Two parts of the study were as follows: (1) to assess the pre-experimental baseline aerosol count in the theatre environment where there are dynamic changes in temperature and humidity and (2) to measure aerosol generation with 23-gauge and 25-gauge set-up. For each porcine eye, five measurements were taken for each consecutive step in the experiment including pre-PPV, during PPV, fluid-air exchange (FAX) and venting using a flute with 23-gauge set-up and a chimney with 25-gauge set-up. Therefore, a total of 200 measurements were recorded. RESULTS: With 23-gauge and 25-gauge PPV, there was no significant difference in aerosol generation in all six channels comparing pre-PPV versus PPV or pre-PPV versus FAX. Venting using flute with 23-gauge PPV showed significant reduction of aerosol ≤1 µm. Air venting using chimney with 25-gauge set-up showed no significant difference in aerosol of ≤1 µm. For cumulative aerosol counts of all particles measuring ≤5 µm, compared with pre-PPV, PPV or FAX, flute venting in 23-gauge set-up showed significant reduction unlike the same comparison for chimney venting in 25-gauge set-up. CONCLUSION: PPV and its associate steps do not generate aerosols ≤10 µm with 23-gauge and 25-gauge set-ups.

The Effect of Improving Basic Preventive Measures in the Perioperative Arena on Staphylococcus aureus Transmission and Surgical Site Infections: A Randomized Clinical Trial.

Importance: Surgical site infections increase patient morbidity and health care costs. The Centers for Disease Control and Prevention emphasize improved basic preventive measures to reduce bacterial transmission and infections among patients undergoing surgery. Objective: To assess whether improved basic preventive measures can reduce perioperative Staphylococcus aureus transmission and surgical site infections. Design, Setting, and Participants: This randomized clinical trial was conducted from September 20, 2018, to September 20, 2019, among 19 surgeons and their 236 associated patients at a major academic medical center with a 60-day follow-up period. Participants were a random sample of adult patients undergoing orthopedic total joint, orthopedic spine, oncologic gynecological, thoracic, general, colorectal, open vascular, plastic, or open urological surgery requiring general or regional anesthesia. Surgeons and their associated patients were randomized 1:1 via a random number generator to treatment group or to usual care. Observers were masked to patient groupings during assessment of outcome measures. Interventions: Sustained improvements in perioperative hand hygiene, vascular care, environmental cleaning, and patient decolonization efforts. Main Outcomes and Measures: Perioperative S aureus transmission assessed by the number of isolates transmitted and the incidence of transmission among patient care units (primary) and the incidence of surgical site infections (secondary). Results: Of 236 patients (156 [66.1%] women; mean [SD] age, 57 [15] years), 106 (44.9%) and 130 (55.1%) were allocated to the treatment and control groups, respectively, received the intended treatment, and were analyzed for the primary outcome. Compared with the control group, the treatment group had a reduced mean (SD) number of transmitted perioperative S aureus isolates (1.25 [2.11] vs 0.47 [1.13]; P = .002). Treatment reduced the incidence of S aureus transmission (incidence risk ratio; 0.56; 95% CI, 0.37-0.86; P = .008; with robust variance clustering by surgeon: 95% CI, 0.42-0.76; P < .001). Overall, 11 patients (4.7%) experienced surgical site infections, 10 (7.7%) in the control group and 1 (0.9%) in the treatment group. Transmission was associated with an increased risk of surgical site infection (8 of 73 patients [11.0%] with transmission vs 3 of 163 [1.8%] without; risk ratio, 5.95; 95% CI, 1.62-21.86; P = .007). Treatment reduced the risk of surgical site infection (hazard ratio, 0.12; 95% CI, 0.02-0.92; P = .04; with clustering by surgeon: 95% CI, 0.03-0.51; P = .004). Conclusions and Relevance: Improved basic preventive measures in the perioperative arena can reduce S aureus transmission and surgical site infections. Trial Registration: ClinicalTrials.gov Identifier: NCT03638947.

Operating room PathTrac analysis of current intraoperative Staphylococcus aureus transmission dynamics.

BACKGROUND: Operating room (OR) reservoir Staphylococcus aureus isolates have been linked to 50% of surgical site infections. We aimed to assess S aureus transmission dynamics in today's ORs to further guide health care-associated infection prevention. METHODS: Forty OR case-pairs were randomly selected for observation in a 5-month prospective cohort study. Case-pair S aureus transmission dynamics were mapped using OR PathTrac. RESULTS: S aureus pathogens were isolated from ≥1 OR reservoirs in 45.7% (37 of 81) of surgical cases, and epidemiologically related transmission events were confirmed in 22.5% (9 of 40) of case-pairs. Patient skin sites and provider hands provided comparable risk of OR S aureus exposure (19 of 481 patient vs 35 of 1,173 provider hands, relative risk [RR], 1.32; 95% confidence interval [CI], 0.77-2.29; P = .32). Environmental contamination at case 2 start was higher than at case 1 start (case 2 start 32 of 152 sites with >20 colony-forming units vs case 1 start 7 of 163 sites with >20 colony-forming units; RR, 4.90; 95% CI, 2.23-10.77; P < .0001). The stopcock contamination rate was not significantly different than our prior study in 2008 (19 of 164 2008 vs 8 of 77 2018; RR, 1.12; 95% CI, 0.51-2.43; P = .78). All epidemiologically related transmission events involved the between-case mode of transmission and phenotype H. CONCLUSIONS: Current OR S aureus exposure threats reliably include patient skin sites and provider hands. Perioperative S aureus preventive measures should extend from patient decolonization to include improved hand decontamination efforts.

Motion-capture system to assess intraoperative staff movements and door openings: Impact on surrogates of the infectious risk in surgery.

OBJECTIVES: We longitudinally observed and assessed the impact of the operating room (OR) staff movements and door openings on surrogates of the exogenous infectious risk using a new technology system. DESIGN AND SETTING: This multicenter observational study included 13 ORs from 10 hospitals, performing planned cardiac and orthopedic surgery (total hip or knee replacement). Door openings during the surgical procedure were obtained from data collected by inertial sensors fixed on the doors. Intraoperative staff movements were captured by a network of 8 infrared cameras. For each surgical procedure, 3 microbiological air counts, longitudinal particles counts, and 1 bacteriological sample of the wound before skin closure were performed. Statistics were performed using a linear mixed model for longitudinal data. RESULTS: We included 34 orthopedic and 25 cardiac procedures. The median frequency of door openings from incision to closure was independently associated with an increased log10 0.3 µm particle (ß, 0.03; standard deviation [SD], 0.01; P = .01) and air microbial count (ß, 0.07; SD, 0.03; P = .03) but was not significantly correlated with the wound contamination before closure (r = 0.13; P = .32). The number of persons (ß, -0.08; SD, 0.03; P < .01), and the cumulated movements by the surgical team (ß, 0.0004; SD, 0.0005; P < .01) were associated with log10 0.3 µm particle counts. CONCLUSIONS: This study has demonstrated a previously missing association between intraoperative staff movements and surrogates of the exogenous risk of surgical site infection. Restriction of staff movements and door openings should be considered for the control of the intraoperative exogenous infectious risk.

Shedding of methicillin-resistant Staphylococcus aureus by colonized patients during procedures and patient care activities.

OBJECTIVE: Medical procedures and patient care activities may facilitate environmental dissemination of healthcare-associated pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). DESIGN: Observational cohort study of MRSA-colonized patients to determine the frequency of and risk factors for environmental shedding of MRSA during procedures and care activities in carriers with positive nares and/or wound cultures. Bivariate analyses were performed to identify factors associated with environmental shedding. SETTING: A Veterans Affairs hospital. PARTICIPANTS: This study included 75 patients in contact precautions for MRSA colonization or infection. RESULTS: Of 75 patients in contact precautions for MRSA, 55 (73%) had MRSA in nares and/or wounds and 25 (33%) had positive skin cultures. For the 52 patients with MRSA in nares and/or wounds and at least 1 observed procedure, environmental shedding of MRSA occurred more frequently during procedures and care activities than in the absence of a procedure (59 of 138, 43% vs 8 of 83, 10%; P 0.9 m from the patient (52 of 138, 38% vs 25 of 138, 18%; P = .0004). Contamination occurred frequently on surfaces touched by personnel (12 of 38, 32%) and on portable equipment used for procedures (25 of 101, 25%). By bivariate analysis, the presence of a wound with MRSA was associated with shedding (17 of 29, 59% versus 6 of 23, 26%; P = .04). CONCLUSIONS: Environmental shedding of MRSA occurs frequently during medical procedures and patient care activities. There is a need for effective strategies to disinfect surfaces and equipment after procedures.

View point: gaps in the current guidelines for the prevention of Methicillin-resistant Staphylococcus aureus surgical site infections.

The authors advocate the addition of two preventative strategies to the current United State's guidelines for the prevention of surgical site infections. It is known that Staphylococcus aureus, including Methicillin-resistant Staphylococcus aureus (MRSA), carriers are at a higher risk for the development of infections and they can easily transmit the organism. The carriage rate of Staph. aureus in the general population approximates 33%. The CDC estimates the carriage rate of MRSA in the United States is approximately 2%. The first strategy is preoperative screening of surgical patients for Staph. aureus, including MRSA. This recommendation is based upon the growing literature which shows a benefit in both prevention of infections and guidance in preoperative antibiotic selection. The second is performing MRSA active surveillance screening on healthcare workers. The carriage rate of MRSA in healthcare workers approximates 5% and there are concerns of transmission of this pathogen to patients. MRSA decolonization of healthcare workers has been reported to approach a success rate of 90%. Healthcare workers colonized with dangerous pathogens, including MRSA, should be assigned to non-patient contact work areas. In addition, there needs to be implemented a safety net for both the worker's economic security and healthcare. Finally, a reporting system for the healthcare worker acquisition and infections with dangerous pathogens needs to be implemented. These recommendations are needed because Staph. aureus including MRSA is endemic in the United States. Policies regarding endemic pathogens which are to be implemented only upon the occurrence of a facility defined "outbreak" have to be questioned, since absence of infections does not mean absence of transmission. Optimizing these policies will require further research but until then we should error on the side of patient safety.

Mycoplasma hominis Infections Transmitted Through Amniotic Tissue Product.

Background: Mycoplasma hominis is a commensal genitourinary tract organism that can cause infections outside the genitourinary tract. We investigated a cluster of M. hominis surgical site infections in patients who underwent spine surgery, all associated with amniotic tissue linked to a common donor. Methods: Laboratory tests of tissue product from the donor, including culture, quantitative real-time polymerase chain reaction (qPCR), and whole-genome sequencing were performed. Use of this amniotic tissue product was reviewed. A multistate investigation to identify additional cases and locate any unused products was conducted. Results: Twenty-seven tissue product vials from a donor were distributed to facilities in 7 states; at least 20 vials from this donor were used in 14 patients. Of these, 4 of 14 (29%) developed surgical site infections, including 2 M. hominis infections. Mycoplasma hominis was detected by culture and qPCR in 2 unused vials from the donor. Sequencing indicated >99% similarity between patient and unopened vial isolates. For 5 of 27 (19%) vials, the final disposition could not be confirmed. Conclusions: Mycoplasma hominis was transmitted through amniotic tissue from a single donor to 2 recipients. Current routine donor screening and product testing does not detect all potential pathogens. Clinicians should be aware that M. hominis can cause surgical site infections, and may not be detected by routine clinical cultures. The lack of a standardized system to track tissue products in healthcare facilities limits the ability of public health agencies to respond to outbreaks and investigate other adverse events associated with these products.

Mycobacterium chimaera infections associated with heater-cooler units in cardiac surgery.

PURPOSE OF REVIEW: Mycobacterium chimaera infections following cardiac surgery have been reported from an increasing number of countries. These infections are characterized by a poor prognosis with a case fatality rate around 50% despite treatment. Since the first description in 2013, our understanding has grown steadily. Several outbreak investigations, case series, and experiments with heater-cooler units (HCUs) have been published. This review summarizes the current knowledge. RECENT FINDINGS: M. chimaera transmission occurs during cardiopulmonary bypass via bioaerosols emitted from contaminated HCU water systems. Manifestations of M. chimaera infection comprise endocarditis, vascular graft infections, surgical site infections, and dissemination. So far, all cases were exposed to a single HCU brand. Samples from the manufacturing site as well as clonality of M. chimaera strains isolated from HCUs and patients suggest a contamination already at time of delivery representing the main source for the outbreak. Nevertheless, HCU contamination in hospitals cannot be excluded. SUMMARY: Improved awareness of physicians of M. chimaera infection is crucial to prompt adequate diagnostic workup in patients that have been exposed to HCU presenting with compatible symptoms. For risk mitigation, strict separation between the air volume in contact with HCUs and critical clinical areas such as operating rooms is essential.

[Spectrum of pathogens in postoperative complications of visceral surgery : The problem of multidrug resistance]. / Erregerspektrum postoperativer Komplikationen in der Viszeralchirurgie : Das Problem der Multiresistenz.

In general surgery the etiology of surgical site infections has not significantly changed over the last 30 years. Gram-positive bacteria, e.g. coagulase negative staphylococci (CNS), Staphylococcus aureus and Enterococcus spp. as well as Gram-negative bacteria, e.g. Escherichia coli, Enterobacter spp., Klebsiella spp. and Pseudomonas aeruginosa, are the most common findings. Although in general surgery 10% of the S. aureus causing postoperative wound infections were methicillin resistant (MRSA), no cases of multidrug-resistant Gram-negative (MRGN) bacteria were reported. Yeasts (particularly Candida spp.) are rarely the pathogen causing surgical site infections (≤3%) and concomitant risk factors are typical (e.g. diabetes, chemotherapy, immunosuppression and malnutrition). Viruses are rarely the cause of surgical site infections. Transmission can occur by HBV, HCV or HIV positive surgical staff or in organ transplantations and postoperative reactivation of persistent infections is possible (especially for HBV, HCV, CMV, EBV and HIV). The principles for prevention of surgical site infections are dealt with as consequences of preoperative colonization by MRSA, methicillin-sensitive S. aureus (MSSA) and MRGN and reviewed with respect to screening, perioperative antibiotic prophylaxis and decolonization. In nosocomial peritonitis, the selection of antibiotics should consider previous antibiotic treatment. A single intra-abdominal detection of Candida spp. usually does not require antimycotic treatment in postoperatively stable and immunocompetent patients but is recommended in severe community-acquired or nosocomial peritonitis. Viral infections can be avoided by screening of organ donors and serological surveillance of surgery personnel.

Survey of Intraoperative Bacterial Contamination in Dogs Undergoing Elective Orthopedic Surgery.

OBJECTIVE: To investigate the frequency, source, and risk factors of intraoperative (IO) surgeon and patient bacterial contamination during clean orthopedic surgeries, and to investigate the relationship between IO contamination and surgical site infection (SSI) in dogs. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Client-owned dogs undergoing stifle surgery (n = 100). METHODS: IO cultures were taken in each case from surgical foot wrap, peri-incisional skin, surgical gloves, and the surgical team's hands. The environment (operating room [OR] lights, computers, scrub sink faucet, anesthesia gurney, and radiology table) was sampled every 5 months. Bacteria were identified and the contamination of each case was categorized. All gloves from the surgical team were collected and tested for perforations using a water infusion test. Cases were followed for at least 8 weeks to determine the presence or absence of SSI. Perioperative variables were evaluated for association with IO contamination and SSI. RESULTS: Bacterial isolates were yielded from 81% of procedures from 1 or more sources; 58% had positive hand cultures, 46% had positive glove cultures, 23% had positive patient skin cultures, and 12% had positive foot wrap cultures. Staphylococcus spp. was the most commonly recovered bacteria. There was no apparent association between IO contamination and SSI. The highest level of environmental contamination was associated with the scrub sink faucet, followed by the radiology table, anesthesia gurney, and OR computers. The IO glove perforation rate was 18%. CONCLUSION: Clean orthopedic procedures commonly had clinically insignificant bacterial contamination. In our study, bacteria responsible for SSI did not appear to colonize the patient in the OR.

[Hospital disinfection challenges due to multiresistant pathogens in surgery]. / Krankenhaushygienische Herausforderungen durch multiresistente Erreger in der Chirurgie.

The number of antibiotic-resistant pathogens is increasing continuously while the development of new, effective antibiotics cannot be expected in the near future. Postoperative infections represent most of the nosocomial infections by now. Based on this, hygienic strategies regain importance, since a sustainable control of nosocomial infections will not succeed without the implementation of such strategies. In this article, the most important preventive strategies for prevention of infections with MRSA and 3- and 4-fold resistant gram-negative bacteria on the basis of current recommendations of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) are presented.

[Infections Associated with Treatment with Hirudo medicinalis - Report of Two Cases and Review of the Literature]. / Infektionen im Zusammenhang mit der Anwendung von Hirudo medicinalis - Zwei Fallberichte und Literaturübersicht.

Medicinal leeches are well-established for promoting venous drainage in transplants/flaps and analgesia in osteoarthritis. Although medicinal leeches are bred and kept under controlled conditions, they are colonised by a genuine species-specific bacterial flora. Therapeutic application of leeches implies skin penetration carrying an a priori risk of infection. We report 2 cases with different indications for medicinal leech therapy. In both cases wound infection occurred in close temporal and spatial correlation or with evidence of a leech-associated germ that could be treated successfully. An unclarified complication rate warrants strict indications for the application of medicinal leeches. Preventive measures are currently tested.

Surface contamination in operating rooms: a risk for transmission of pathogens?

BACKGROUND: The role of surface contamination in the transmission of nosocomial pathogens is recognized increasingly. For more than 100 years, the inanimate environment in operating rooms (e.g., walls, tables, floors, and equipment surfaces) has been considered a potential source of pathogens that may cause surgical site infections (SSIs). However, the role of contaminated surfaces in pathogen acquisition in this setting generally is considered negligible, as most SSIs are believed to originate from patients' or healthcare workers' flora. METHODS: A search of relevant medical literature was performed using PubMed to identify studies that investigated surface contamination of operating rooms and its possible role in infection transmission. RESULTS: Despite a limited number of studies evaluating the role of surface contamination in operating rooms, there is accumulating evidence that the inanimate environment of the operating room can become contaminated with pathogens despite standard environmental cleaning. These pathogens can then be transmitted to the hands of personnel and then to patients and may result in SSIs and infection outbreaks. CONCLUSION: Contaminated surfaces can be responsible for the transmission of pathogens in the operating room setting. Further studies are necessary to quantify the role of contaminated surfaces in the transmission of pathogens and to inform the most effective environmental interventions. Given the serious consequences of SSIs, special attention should be given to the proper cleaning and disinfection of the inanimate environment in operating rooms in addition to the other established infection control measures to reduce the burden of SSIs.

Staphylococcus aureus screening and decolonization in orthopaedic surgery and reduction of surgical site infections.

BACKGROUND: Staphylococcus aureus is the most common organism responsible for orthopaedic surgical site infections (SSIs). Patients who are carriers for methicillin-sensitive S. aureus or methicillin-resistant S. aureus (MRSA) have a higher likelihood of having invasive S. aureus infections. Although some have advocated screening for S. aureus and decolonizing it is unclear whether these efforts reduce SSIs. QUESTIONS/PURPOSES: The purposes of this study were to determine (1) whether S. aureus screening and decolonization reduce SSIs in orthopaedic patients and (2) if implementing this protocol is cost-effective. METHODS: Studies for this systematic review were identified by searching PubMed, which includes MEDLINE (1946-present), EMBASE.com (1974-present), and the Cochrane Library's (John Wiley & Sons) Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment Database (HTAD), and the NHS Economic Evaluation Database (NHSEED). Comprehensive literature searches were developed using EMTREE, MeSH, and keywords for each of the search concepts of decolonization, MRSA, and orthopedics/orthopedic surgery. Studies published before 1968 were excluded. We analyzed 19 studies examining the ability of the decolonization protocol to reduce SSIs and 10 studies detailing the cost-effectiveness of S. aureus screening and decolonization. RESULTS: All 19 studies showed a reduction in SSIs or wound complications by instituting a S. aureus screening and decolonization protocol in elective orthopaedic (total joints, spine, and sports) and trauma patients. The S. aureus screening and decolonization protocol also saved costs in orthopaedic patients when comparing the costs of screening and decolonization with the reduction of SSIs. CONCLUSIONS: Preoperative screening and decolonization of S. aureus in orthopaedic patients is a cost-effective means to reduce SSIs. LEVEL OF EVIDENCE: Level IV, systematic review of Level I-IV studies. See the Guidelines for Authors for a complete description of levels of evidence.

[The hospital-borne tetanus in the reference service of the Donka National Hospital in Conakry (2001-2011)]. / Le tétanos nosocomial dans le service de référence de l'hôpital National Donka à Conakry (2001-2011).

Become almost non-existent in the developed countries, the hospital-borne tetanus always stays of current events in our country in spite of the forensic problem which it puts. The objectives of this study were to determine prevalence of this affection, to describe its clinical picture and to determine its lethality. It is about a retrospective study of a duration of 11 years realized in the service of the infectious diseases of Conakry. Among 8649 hospitalizations from 2001 till 2012 we brought together 239 cases of tetanus (2.7%) among which 60 hospital-borne tetanus (0.7%). Men represented 73% of these cases, with a sex-ratio M/F of 2.7. The age bracket of 20-40 years was the most affected with 32 cases (53.3%). A single patient had begun his vaccinal calendar which had remained incomplete. Both national hospitals of the CHU of Conakry and private hospitals were the biggest suppliers of this hospital-borne tetanus with respectively 22 and 27 cases (36.6 and 45%). Tetanus related to IM of quinine represented 26 cases (43.3%) whereas the hernial cure was found in 16 cases (26.6%). The average duration of invasion and incubation was respectively 1.5 days and 6 days for the dead (n = 45.7%) and 2 days and 10.5 days for the survivors. Three-quarters of 60 patients died. The fight against this type of tetanus passes inevitably by an improvement of the working conditions, a strict application of the rules of asepsis and the in-service training of the medical and paramedical staff.

Is arthroplasty immediately after an infected case a risk factor for infection?

BACKGROUND: It is common practice in many centers to avoid performing a clean case in a room in which an infected procedure has just taken place. No studies of which we are aware speak to the necessity of this precaution. QUESTIONS/PURPOSES: The purposes of this study were to identify (1) the risk of infection in a group of patients who underwent arthroplasties performed immediately after a first-stage arthroplasty for joint infection; and (2) the risk of superficial and deep infections in these patients compared with a matched group of patients who underwent arthroplasties not performed after an infected surgery. METHODS: Eighty-three patients (85 arthroplasties) who underwent arthroplasties (primary or revision) immediately after patients with known infections underwent surgery in the same operating room (OR) were analyzed for 12 months after surgery to determine the incidence of infection. They were matched for demographic factors and surgery type with a control group of 321 patients (354 arthroplasties) who underwent surgery in an OR that had not just been used for surgery involving patients with infections. We compared the risk of superficial and deep infections between the groups. RESULTS: Patients in the study group were not more likely to have infections develop than those in the control group. One patient in the study group (1.17%) and three in the control group (0.84%) had deep infections develop; the infection in the patient in the study group was caused by a different organism than that of the patient with an infection whose surgery preceded in the OR. Two superficial infections (2.35%) were detected in the study group and 17 (4.8%) were detected in the control group. CONCLUSIONS: With the numbers available, we found that a deep infection was not more likely to occur in a patient without an infection after an arthroplasty that followed surgery on a patient with an infection than in one who had surgery after a clean case. Although sample size was a potential issue in this study, the results may serve as hypothesis generating for future studies. LEVEL OF EVIDENCE: Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.