Relation between nasal carriage of Staphylococcus aureus and surgical site infection in orthopedic surgery: the role of nasal contamination. A systematic literature review and meta-analysis

Antimicrobial Resistance Profiles and mupA Gene Characterization of Staphylococcus epidermidis Recovered from Facial Skin of Healthy Females in Shanghai, China

Purpose

To explore antimicrobial resistance profiles and mupA gene characterization of Staphylococcus epidermidis recovered from facial skin of healthy females in Shanghai, China.

Patients and Methods

In this study, we collected facial skin samples from 107 healthy females in Shanghai, China, and S. epidermidis isolation was performed. The minimal inhibitory concentrations of 10 antibiotics were determined for the S. epidermidis isolates using the agar dilution method. High-level mupirocin-resistant isolates were subjected to whole-genome sequencing and bioinformatics analysis. A total of 94 un-duplicated S. epidermidis isolates were obtained from 107 facial skin samples.

Results

Antimicrobial susceptibility tests revealed that 23.4% of the 94 S. epidermidis isolates were resistant to oxacillin and positive for the mecA gene, which could be cauterized as methicillin-resistant S. epidermidis (MRSE). Resistance rates for erythromycin, clindamycin, tetracycline, ciprofloxacin, and gentamicin were 8.5%, 11.7%, 10.6%, 12.8%, and 1.1%, respectively. For mupirocin, the rates of low- and high-level resistance were 3.2% (3/94) and 11.7% (11/94), respectively. Resistance to vancomycin or linezolid was not observed. High-level mupirocin resistance in facial skin isolates is mediated by mupA. WGS and SNP-based phylogenetic analyses revealed diverse phylogenies among the 11 mupA-positive S. epidermidis isolates. Additionally, various resistance and virulence genes were identified in mupA-positive isolates. A new hybrid plasmid carrying mupA genes was found in two S. epidermidis isolates.

Conclusion

We observed a considerable level of antimicrobial resistance to several antibiotics and the prevalence of abundant and diverse resistance and virulence genes in the facial skin-origin S. epidermidis isolates. This may pose a potential risk for both public health and S. epidermidis infection.

Randomized Controlled Trial: Does the Use of Occlusive Hydrocolloid Silver-Containing Wound Dressing after Sternotomy Reduce Surgical Site Infection after Cardiac Surgery?

(1) Background: To reduce the incidence of surgical site infections (SSIs) following median sternotomy in cardiac surgery, we compared an occlusive hydrocolloid silver-containing wound dressing (OHSCWD) with a standard wound dressing. (2) Methods: This study was designed as a single-center randomized controlled trial. The primary endpoint was the overall rate of incidence of any kind of SSI. Secondary endpoints were the number of dressing changes, the severity of SSIs, and whether there was a need for treatment. Wounds were monitored daily until the seventh and on the 30th postoperative day. (3) Results: Of the 423 patients included, 352 were analyzed. No differences in demographics, cardiovascular risk factors, intraoperative processes, and postoperative care were found between both groups. Additionally, the incidence or extent of SSI showed no significant differences between the two groups. (4) Conclusions: In summary, out of all pre-, intra-, and postoperative factors, the contribution of postoperative wound care to the development of SSIs appears to play a subordinate role. However, by offering equivalent wound protection and a reduced number of dressing changes, OHSCWD after median sternotomy in cardiac surgery patients could be a good alternative to standard dressings from the point of view of the patient, the staff, and the clinic.

Staphylococcus aureus screening and preoperative decolonisation with Mupirocin and Chlorhexidine to reduce the risk of surgical site infections in orthopaedic surgery: a pre-post study

BACKGROUND

Nasal carriage of Staphylococcus aureus is a risk factor for surgical site infections (SSI) in orthopaedic surgery. The efficacy of decolonisation for S. aureus on reducing the risk of SSI is uncertain in this speciality. The objective was to evaluate the impact of a nasal screening strategy of S. aureus and targeted decolonisation on the risk of S. aureus SSI.

METHODS

A retrospective pre-post and here-elsewhere study was conducted between January 2014 and June 2020 in 2 adult orthopaedic surgical sites (North and South) of a French university hospital. Decolonisation with Mupirocin and Chlorhexidine was conducted in S. aureus carriers starting February 2017 in the South site (intervention group). Scheduled surgical procedures for hip, knee arthroplasties, and osteosyntheses were included and monitored for one year. The rates of S. aureus SSI in the intervention group were compared to a historical control group (South site) and a North control group. The risk factors for S. aureus SSI were analysed by logistic regression.

RESULTS

A total of 5,348 surgical procedures was included, 100 SSI of which 30 monomicrobial S. aureus SSI were identified. The preoperative screening result was available for 60% (1,382/2,305) of the intervention group patients. Among these screenings, 25.3% (349/1,382) were positive for S. aureus and the efficacy of the decolonisation was 91.6% (98/107). The rate of S. aureus SSI in the intervention group (0.3%, 7/2,305) was not significantly different from the historical control group (0.5%, 9/1926) but differed significantly from the North control group (1.3%, 14/1,117). After adjustment, the risk factors of S. aureus SSI occurrence were the body mass index (ORaper unit, 1.05; 95%CI, 1.0-1.1), the Charlson comorbidity index (ORaper point, 1.34; 95%CI, 1.0-1.8) and operative time (ORaper minute, 1.01; 95%CI, 1.00-1.02). Having benefited from S. aureus screening/decolonisation was a protective factor (ORa, 0.24; 95%CI, 0.08-0.73).

CONCLUSIONS

Despite the low number of SSI, nasal screening and targeted decolonisation of S. aureus were associated with a reduction in S. aureus SSI.

Antimicrobial resistance is not increasing in subsequent cases of ischaemic foot infections, a single-centre cohort from 2012 to 2021

Patients with chronic limb-threatening ischaemia (CLTI) are at risk of foot infections, which is associated with an increase in amputation rates. The use of antibiotics may lead to a higher incidence of antimicrobial resistance (AMR) in subsequent episodes of ischaemic foot infections (IFI). This retrospective single-centre cohort study included 130 patients with IFI undergoing endovascular revascularisation. Staphylococcus aureus and Pseudomonas aeruginosa were the two most common pathogens, accounting for 20.5% and 10.8% of cases, respectively. The prevalence of antimicrobial resistance (AMR) and multi-drug resistance did not significantly increase between episodes (10.2% vs. 13.4%, p = 0.42). In 59% of subsequent episodes, the identified pathogens were unrelated to the previous episode. However, the partial concordance of identified pathogens significantly increased to 66.7% when S. aureus was identified (p = 0.027). Subsequent episodes of IFI in the same patient are likely to differ in causative pathogens. However, in the case of S. aureus, the risk of reinfection, particularly with S. aureus, is increased. Multi-drug resistance does not appear to change between IFI episodes. Therefore, recommendations for empirical antimicrobial therapy should be based on local pathogen and resistance statistics without the need to broaden the spectrum of antibiotics in subsequent episodes.

Addition of vancomycin to cefazolin is often unnecessary for preoperative antibiotic prophylaxis during total joint arthroplasties

PURPOSE

The gold standard to decrease total joint arthroplasty (TJA) periprosthetic joint infection (PJI) is preoperative antibiotic prophylaxis. Despite substantial prevention efforts, rates of PJIs are increasing. While cefazolin is the drug of choice for preoperative prophylaxis, adjunctive vancomycin therapy has been used in methicillin-resistant Staphylococcus aureus (MRSA) endemic areas. However, studies examining these combinations are lacking. Therefore, we sought to examine complications among vancomycin plus cefazolin and cefazolin-only recipients prior to primary TJA in a single institutional sample and specifically assessed: (1) microbiological aspects, including periprosthetic joint and surgical site infections, microbes cultured from the infection, and frequency of microbes cultured from nasal swab screening; (2) 30-day emergency department (ED) visits and re-admissions; as well as (3) associated risk factors for infection.

METHODS

A total of 2,907 patients (1,437 receiving both cefazolin and vancomycin and 1,470 given cefazolin only) who underwent primary TJA between 1 January 2014 and 31 May 2021 were identified. SSI and PJI as well as rates of cultured microbes rates were obtained through one year, those with prior nasal swab screening and 30-day re-admission were identified. Subsequently, multiple regression analyses were performed to investigate potential independent risk factors for PJIs.

RESULTS

There was no significant difference in the rates of SSI (P = 0.089) and PJI (P = 0.279) between the groups at one year after operation. Commonly identified organisms included Staphylococcus and Streptococcus species. The VC cohort did have a greater reduction of MRSA in the previously nasal swab-screened subset of patients. Multiple regression analyses demonstrated emergency as well as inpatient admissions as risk factors for PJI.

CONCLUSIONS

Adjunctive vancomycin therapy offers increased protection against MRSA in previously screened individuals. However, those negative for MRSA screening do not require vancomycin and have similar protection to infection compared to recipients of cefazolin only in a high-powered single institution analysis in an MRSA endemic area.

Prevalence of surgical site wound infection after spine surgery in nasal colonization of methicillin-resistant Staphylococcus aureus: A meta-analysis

The purpose of the meta-analysis was to evaluate and compare the prevalence of surgical site infection (SSI) after spine surgery (SS) in nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA). The results of this meta-analysis were analysed, and the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated using dichotomous or contentious random- or fixed-effect models. For the current meta-analysis, 14 examinations spanning from 2014 to 2022 were included, encompassing 18 410 people who were tested for nasal colonization after SS. MRSA-positive had a significantly higher SSI (OR, 3.65; 95% CI, 2.48-5.37, p < 0.001) compared with MRSA-negative in SS subjects. However, no significant difference was found between methicillin-susceptible Staphylococcus aureus and Staphylococcus aureus negative (OR, 0.94; 95% CI, 0.32-2.79, p = 0.91), and Staphylococcus aureus positive and negative (OR, 2.13; 95% CI, 0.26-17.41, p = 0.48) in SS subjects. The examined data revealed that MRSA colonization had a significant effect on SSI; however, methicillin-susceptible Staphylococcus aureus and Staphylococcus aureus had no significant effect on SSI in SS subjects. However, given that some comparisons included a small number of chosen studies, attention should be given to their values.

Increased prevalence of Staphylococcus aureus nasal carriage in rheumatoid arthritis patients with moderate/high disease activity

BACKGROUND

Staphylococcus aureus (S. aureus) nasal carriage is a well-known risk factor for surgical site infection (SSI) after total joint arthroplasty. This study aimed to compare the prevalence of S. aureus nasal carriage between patients with osteoarthritis (OA), a degenerative joint disease, and those with rheumatoid arthritis (RA), a chronic autoimmune inflammatory disease, who underwent total joint arthroplasty, and to investigate the influence of RA disease activity on nasal carriage rate.

METHODS

This retrospective study targeted 508 OA and 107 RA patients who underwent S. aureus nasal screening prior to primary total knee and/or hip arthroplasty. RA patients were divided into two groups based on disease activity: the remission/low disease activity (REM/LDA) group and the moderate/high disease activity (MDA/HDA) group. Factors associated with S. aureus nasal carriage were assessed with multivariate logistic regression models.

RESULTS

Of all 615 patients, 155 (25%) carried S. aureus in their nares. Compared to OA patients, RA patients had a significantly higher rate of S. aureus nasal carriage (24% vs. 33%, p = 0.049). Compared to the REM/LDA group (n = 39), the MDA/HDA group (n = 58) had a significantly higher rate of S. aureus nasal carriage (21% vs. 41%, p = 0.032). Multivariate analysis revealed that the MDA/HDA group, but not the REM/LDA group, had a significantly higher odds of S. aureus nasal carriage compared to the OA group (odds ratio: 2.76, 95% confidence interval: 1.07-7.12).

CONCLUSION

Preoperative nasal screening for S. aureus is beneficial, especially in RA patients with moderate/high disease activity.

[Translated article] Results of a preoperative screening and decolonization programme for Staphylococcus aureus in primary hip and knee arthroplasty

INTRODUCTION

Detection and decolonization of Staphylococcus aureus prior to surgery is postulated as an option to reduce the risk of infection in arthroplasties. The aim of this study was to evaluate the effectiveness of a screening programme for S. aureus in total knee arthroplasty (TKA) and total hip arthroplasty (THA), the incidence of infection with respect to a historical cohort, and its economic viability.

MATERIAL AND METHODS

Pre-post intervention study in patients undergoing primary knee and hip prostheses in 2021, a protocol was carried out to detect nasal colonization by S. aureus and eradication if appropriate, with intranasal mupirocin, post-treatment culture with results three weeks between post-treatment culture and surgery. Efficacy measures are evaluated, costs are analyzed and the incidence of infection is compared with respect to a historical series of patients operated on between January and December 2019, performing a descriptive and comparative statistical analysis.

RESULTS

The groups were statistically comparable. Culture was performed in 89%, with 19 (13%) positive patients. Treatment was confirmed in 18, control culture in 14, all decolonized; none suffered infection. One culture-negative patient suffered from Staphylococcus epidermidis infection. In historical cohort: three suffered deep infection by S. epidermidis, Enterobacter cloacae, Staphylococcus aureus. The cost of the programme is €1661.85.

CONCLUSION

The screening programme detected 89% of the patients. The prevalence of infection in the intervention group was lower than in the cohort, with S. epidermidis being the main micro-organism, different from S. aureus described in the literature and in the cohort. We believe that this programme is economically viable, as its costs are low and affordable.

Risk factors for preoperative nasal carriage of methicillin-resistant bacteria in total hip and knee arthroplasty patients

BACKGROUND

The present study aimed to identify risk factors for preoperative nasal carriage of resistant bacteria - MRSA methicillin-resistant Staphylococcus (S.) aureus, MRSE (methicillin-resistant Staphylococcus epidermidis), and MRCNS (methicillin-resistant coagulase negative staphylococci) in total hip and knee arthroplasty (THA and TKA) patients.

METHODS

Nasal cultures were obtained from 538 patients before THA (262 primary and 26 revision) and TKA (241 primary and 9 revision). These were classified either as methicillin-resistant bacteria (group MR) or methicillin-susceptible bacteria (including culture-negative) (group MS). Patient characteristics were compared between these groups using logistic regression models.

RESULTS

The resistant bacteria were preoperatively present in 33.1% (178 patients) among all patients. MRSE, MRCNS, and MRSA were detected in 27.5% (148 patients), 3.7% (20 patients), and 1.9% (10 patients). In the unadjusted comparisons of the patient characteristics between the groups MR and MS, a significant difference was found in the percentages of diabetic patients (15.2% vs. 9.2%, P = 0.04); the association remained after the multivariable adjustment for possible risk factors (P < 0.001). In addition, the diabetic patients in the group MR showed a higher percentage of receiving insulin injection than those in the group MS (25.9% vs. 6.1%, P = 0.063), and their mean levels of HbA1c were significantly higher in the group MR than the MS (6.8% vs. 6.4%, P = 0.03).

CONCLUSIONS

We identified diabetes as a risk factor for the preoperative nasal carriage of resistant bacteria. Our results suggest that, in order to prevent a surgical site infection (SSI), extra care should be taken in performing joint arthroplasties for diabetic patients, especially using insulin and with high HbA1c levels (≥6.6%) prior to the surgical procedures.

Efficacy of mupirocin, neomycin and octenidine for nasal Staphylococcus aureus decolonisation: a retrospective cohort study

BACKGROUND

Periprosthetic joint infection (PJI) causes significant morbidity. Methicillin sensitive Staphylococcus aureus (MSSA) is the most frequent organism, and the majority are endogenous. Decolonisation reduces PJIs but there is a paucity of evidence comparing treatments. Aims; compare 3 nasal decolonisation treatments at (1) achieving MSSA decolonisation, (2) preventing PJI.

METHODS

Our hospital prospectively collected data on our MSSA decolonisation programme since 2013, including; all MSSA carriers, treatment received, MSSA status at time of surgery and all PJIs. Prior to 2017 MSSA carriers received nasal mupirocin or neomycin, from August 2017 until August 2019 nasal octenidine was used.

RESULTS

During the study period 15,958 primary hip and knee replacements were performed. 3200 (20.1%) were MSSA positive at preoperative screening and received decolonisation treatment, 698 mupirocin, 1210 neomycin and 1221 octenidine. Mupirocin (89.1%) and neomycin (90.9%) were more effective at decolonisation than octenidine (50.0%, P < 0.0001). There was no difference in PJI rates (P = 0.452).

CONCLUSIONS

Mupirocin and neomycin are more effective than octenidine at MSSA decolonisation. There was poor correlation between the MSSA status after treatment (on day of surgery) and PJI rates. Further research is needed to compare alternative MSSA decolonisation treatments.

Strategies for the implementation of a nasal decolonization intervention to prevent surgical site infections within the Veterans Health Administration

As part of a multicenter evidence-based intervention for surgical site infection prevention, a qualitative study was conducted with infection control teams and surgical staff members at three Department of Veterans Affairs Healthcare Systems in the USA. This study aimed to identify strategies used by nurses and other facility champions for the implementation of a nasal decolonization intervention. Site visit observations and field notes provided contextual information. Interview data were analyzed with inductive and deductive content analysis. Interview data was mapped to the Expert Recommendations for Implementing Change (ERIC) compilation of implementation strategies. These strategies were then considered in the context of power and relationships as factors that influence implementation. We found that implementation of this evidence-based surgical site infection prevention intervention was successful when nurse champions drove the day-to-day implementation. Nurse champions sustained implementation strategies through all phases of implementation. Findings also suggest that nurse champions leveraged the influence of their role as champion along with their understanding of social networks and relationships to help achieve implementation success. Nurse champions consciously used multiple overlapping and iterative implementation strategies, adapting and tailoring strategies to stakeholders and settings. Commonly used implementation categories included: "train and educate stakeholders," "use evaluative and iterative strategies," "adapt and tailor to context," and "develop stakeholder interrelationships." Future research should examine the social networks for evidence-based interventions by asking specifically about relationships and power dynamics within healthcare organizations. Implementation of evidence-based interventions should consider if the tasks expected of a nurse champion fit the level of influence or power held by the champion.

Trial registration

ClinicalTrials.gov, identifier: NCT02216227.

Impact of surgical clothing and footwear on operating room contamination during standstill and intraoperative stepping motion

BACKGROUND

In view of preventing surgical site infection (SSI) in the orthopedic operating room (OR), evidence concerning types of footwear and clothing is limited. This study aimed to investigate how different footwear and clothing affect the cleanliness of the OR environment.

METHODS

The airborne dust concentration in a bioclean room (NASA class 100) was measured around an operator by using a handheld particle counter under the following conditions: (I) wearing a sterilized full-type space suit with OR dedicated clean sandals; (II) wearing a sterilized full-type space suit with non-dedicated (outside) shoes or severely contaminated outside shoes with surgical glove powder (2 µm mean particle size); and (III) wearing an unsterilized medical scrub uniform with OR dedicated sandals. The participant was standing still or stepping in place at 1 Hz during the testing.

RESULTS

The concentrations of airborne dusts in the operative field were independent of footwear and clothing types under the stand-still condition. However, these values significantly increased 1.96- to 16.23-fold after simple stepping motion in all the test conditions, and often became dissatisfaction level with the NASA100 requirement for the OR cleanliness. The worst contamination occurred when an operator wore the powder-contaminated shoes and also the unsterilized scrub uniform.

CONCLUSION

The present study showed that the stepping motion triggered a considerable contamination in the operative field (beyond the level of NASA100 threshold) particularly when an operator used the outside shoes or unsterilized scrub uniform. Therefore, these results tell us that the one-footwear system (i.e., no use of OR dedicated clean shoes) and unsterilized scrub are likely to be a potential risk factor for SSI. Nevertheless, further studies are necessary to conclude the real efficacy of OR dedicated shoes and sterilized clothes on the SSI prevention.

Efficacy of preoperative screening and decolonization for staphylococcus aureus in total joint arthroplasty: A meta-analysis

The purpose of this study is to conduct a meta-analysis to evaluate the efficacy of screening and decolonization protocol for Staphylococcus aureus (SA) in total joint arthroplasty (TJA). We systematically searched the electronic databases of PubMed, Embase and Cochrane databases for relevant literatures from January 2000 to September 2020. The outcomes were colonization rate, total-surgical site infection (SSI) rate, SA-SSI rate and methicillin-resistant Staphylococcus aureus (MRSA)-SSI rate. All calculations and statistical tests were performed using Stata 14.0 software. A total of 12 studies were eligible in this study. Compared with control group, the screening and decolonization group had lower risks in total-SSI (risk ratio (RR) = 0.52; 95% confidence interval (CI): 0.40-0.67), SA-SSI (RR = 0.48; 95% CI: 0.32-0.72) and MRSA-SSI (RR = 0.45; 95% CI: 0.21-0.96). The nasal SA colonization was found to be associated with higher accidences of SSI involving total-SSI (RR = 1.49; 95% CI: 1.02-2.18), SA-SSI (RR = 2.51; 95% CI: 0.97-6.50) and MRSA-SSI (RR = 7.84; 95% CI: 1.67-36.79). The colonization rate of SA was significantly reduced after decolonization. No difference was observed between universal decolonization and screening-based decolonization. In conclusion, colonization of SA is associated with increased risk of SSI in TJA. Screening and decolonization protocol are proven to be effective to reduce colonization of SA and present protective effects against SSI in TJA. Moreover, universal decolonization protocol is non-inferior to screening-based decolonization.

[Risk factors for multiple debridements of the patients with deep incisional surgical site infection after spinal surgery]

OBJECTIVE

To investigate the risk factors that contribute to multiple debridements in patients suffering from deep incisional surgical site infection after spinal surgery and advise medical personnel to pay special attention to these risk factors.

METHODS

We retrospectively enrolled 84 patients who got deep incisional surgical site infection after spinal surgery from Jan. 2012 to Dec. 2017. The infections occurred within 30 days after the surgery, and the identification met the criteria of deep incisional surgical site infection of Centers of Disease Control (CDC). Early debridement with first stage closure of the wound and a continuous inflow-outflow irrigation system was used, and reasonable antibiotics were chosen according to the bacterial culture results. During the treatment, the vital signs, clinical manifestations, blood test results, drainage fluid colour and bacterial culture results were acquired. If the infection failed to be controlled or relapsed, a second debridement was performed. Of the 84 cases, 60 undergwent single debridement which included 36 male cases and 24 female cases, and the age ranged from 36 to 77 years, with a mean of 57.2 years. Twenty four had multiple debridements (twice in 14 cases, three times in 6 cases, four times in 1 case, five times in 2 cases, six times in 1 cases) which included 17 male cases and 7 female cases, and the age ranged from 21 to 70 years, with a mean of 49.5 years. Risk factors that predispose patients to multiple debridements were identified using univariate analysis. Risk factors with P values less than 0.05 in univariate analysis were included together in a multivariate Logistic regression model using back-forward method.

RESULTS

Multiple debridements were performed in 28.6% of all cases. The hospital stay of multiple debridements group was (82.4±46.3) days compared with (40.4±31.5) days in single debridement group (P=0.018). Instrumentation was removed in 6 cases in multiple debridements group and 4 cases in single debridement group (P=0.049). Flap transplantation was performed in 7 cased in multiple debridements group while none in single debridement group (P < 0.001). Diabetes, primary operation duration longer than 3 hours, primary operation blood loss more than 400 mL, bacteriology examination results, distant site infection were significantly different between the two groups in univariate analysis. In multivariate analysis, primary operation duration longer than 3 hours (OR=3.60, 95%CI: 1.12-11.62), diabetes (OR=3.74, 95%CI: 1.06-13.22), methicillin-resistant Staphylococcus aureus (MRSA) infected (OR=16.87, 95%CI: 2.59-109.73) were the most important risk factors related to multiple debridements in the patients with deep incisional surgical site infection after spinal surgery.

CONCLUSION

Diabetes, primary operation duration more than 3 hours, MRSA infected are independent risk factors for multiple debridements in patients suffering from deep incisional surgical site infection after spinal surgery. Special caution and prophylaxis interventions are suggested for these factors.

Presence of the neonatal Staphylococcus capitis outbreak clone (NRCS-A) in prosthetic joint infections

Staphylococcus capitis is a coagulase-negative staphylococcus that has been described primarily as causing bloodstream infections in neonatal intensive care units (NICUs), but has also recently been described in prosthetic joint infections (PJIs). The multidrug-resistant S. capitis subsp. urealyticus clone NRCS-A, comprising three sublineages, is prevalent in NICUs across the world, but its impact on other patient groups such as those suffering from PJIs or among adults planned for arthroplasty is unknown. Genome sequencing and subsequent analysis were performed on a Swedish collection of PJI isolates (n = 21), nasal commensals from patients planned to undergo arthroplasty (n = 20), NICU blood isolates (n = 9), operating theatre air isolates (n = 4), and reference strains (n = 2), in conjunction with an international strain collection (n = 248). The NRCS-A Outbreak sublineage containing the composite type V SCCmec-SCCcad/ars/cop element was present in PJIs across three Swedish hospitals. However, it was not found among nasal carrier strains, where the less virulent S. capitis subsp. capitis was most prevalent. The presence of the NRCS-A Outbreak clone in adult patients with PJIs demonstrates that dissemination occurs beyond NICUs. As this clone has several properties which facilitate invasive infections in patients with medical implants or immunosuppression, such as biofilm forming ability and multidrug resistance including heterogeneous glycopeptide-intermediate susceptibility, further research is needed to understand the reservoirs and distribution of this hospital-associated pathogen.

Does Preoperative Decolonization Reduce Surgical Site Infections in Elective Orthopaedic Surgery? A Prospective Randomized Controlled Trial

BACKGROUND

Surgical site infections (SSIs) after elective orthopaedic surgery are very stressful for patients due to frequent rehospitalizations with reoperations and poorer functional outcomes. Prevention of such events is therefore crucial. Although an evidence-based consensus is still lacking, preoperative decolonization could decrease SSI. Specifically, more information is needed about the effect of a preoperative decolonization procedure on SSI proportions in both Staphylococcus aureus carriers and non-S. aureus carriers after general orthopaedic surgery.

QUESTIONS/PURPOSES

Our study addressed the following questions: (1) Does preoperative decolonization reduce the risk of SSI after general elective orthopaedic surgery in patients colonized with S. aureus? (2) Does preoperative decolonization reduce the risk of SSI among patients who are not colonized with S. aureus?

METHODS

In this prospective, randomized, single-blinded trial, we recruited patients undergoing general elective orthopaedic surgery in one tertiary care center in Switzerland. Between November 2014 and September 2017, 1318 of 1897 screened patients were enrolled. Patients were allocated into either the S. aureus carrier group (35%, 465 of 1318 patients) or the noncarrier group (65%, 853 of 1318 patients) according to screening culture results. In the S. aureus group, 232 patients were allocated to the intervention arm and 233 were allocated to the control arm. Intervention was 5 days of daily chlorhexidine showers and mupirocin nasal ointment twice a day. Of the 853 noncarriers, 426 were allocated to the intervention arm and 427 were allocated to the control arm. All patients in both groups were analyzed in an intention-to-treat manner. The primary endpoint was SSI occurrence at 90 days postoperative and the secondary endpoint was SSI occurrence at 30 days postoperative.The initial sample size calculation was made for the S. aureus carrier group. Based on the literature review, a 4% proportion of SSI was expected in the control group. Thus, 726 carriers would have been needed to detect a relative risk reduction of 80% with a power of 80% at a two-sided α-error of 0.048 (adjusted for interim analysis). Assuming carrier prevalence of 27%, 2690 patients would have been needed in total. An interim analysis was performed after including half of the targeted S. aureus carriers (363 of 726). Based on the low infection rate in the control group (one of 179), a new sample size of 15,000 patients would have been needed. This was deemed not feasible and the trial was stopped prematurely.

RESULTS

Among carriers, there was no difference in the risk of SSI between the intervention and control arms (decolonized SSI risk: 0.4% [one of 232], control SSI risk: 0.4% [one of 233], risk difference: 0.0% [95% CI -1.2% to 1.2%], stratified for randomization stratification factors; p > 0.999). For noncarriers, there was no difference in risk between the intervention and control arms (decolonized SSI risk: 0.2% [one of 426], control SSI risk: 0.2% [one of 247], stratified risk difference: -0.0% [95% CI -0.7 to 0.6]; p = 0.973).

CONCLUSIONS

We found no difference in the risk of SSI between the decolonization and control groups, both in S. aureus carriers and noncarriers. Because of the low event numbers, no definite conclusion about efficacy of routine preoperative decolonization can be drawn. The results, however, may be helpful in future meta-analyses.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Diagnostic Accuracy of Presurgical Staphylococcus aureus PCR Assay Compared with Culture and Post-PCR Implementation Surgical Site Infection Rates

Nasal colonization with Staphylococcus aureus is a well-referenced risk factor for postoperative surgical site infections (SSIs). Our health care system that performs >40,000 surgeries per year assessed both the diagnostic accuracy of the BD MAX StaphSR assay (MAX StaphSR), a PCR-based test that detects and differentiates S. aureus and methicillin-resistant S. aureus (MRSA), compared with our standard of care culture and the subsequent clinical impact on SSIs 1 year after implementation. In addition, residual specimens were tested by broth-enriched culture. Performance parameters for all methods were determined using latent class analysis. Direct culture was the least sensitive for S. aureus (85.1%) and MRSA (76.7%), whereas the MAX StaphSR assay and broth-enriched culture had similar sensitivities (96.7%) for MRSA. Prospective assessment using MAX StaphSR during a 1-year, postimplementation period revealed a lower rate of SSIs per 100 targeted surgeries (0.3) compared with MRSA-only screening (1.10) and no screening (2.28) (P < 0.05 for StaphSR versus MRSA-only screening and StaphSR versus no testing). MRSA and methicillin-sensitive S. aureus SSIs occurred equally (n = 14 each). The MAX StaphSR assay provided accurate detection of both S. aureus and MRSA nasal colonization in presurgical patients, allowing infection prevention measures, including presurgical prophylaxis, to be implemented in a timely and consistent manner to avoid SSIs.

Screening for and decolonization of Staphylococcus aureus carriers before total joint replacement is associated with lower S aureus prosthetic joint infection rates

BACKGROUND

Prosthetic joint infections (PJI) can be devastating postoperative complications after total joint replacement (TJR). The role of decolonization of Staphylococcus aureus carriers prior to surgery still remains unclear, and the most recent guidelines do not state a formal recommendation for such strategy. Our purpose was to seek further evidence supporting preoperative screening and S aureus decolonization in patients undergoing TJR.

METHODS

This was a quasiexperimental quality improvement study comparing a 5-year baseline of deep and organ-space PJIs (2005- 2010) to a 1-year intervention period (May 2015 to July 2016). The intervention consisted of nasal and throat screening for S aureus preoperatively and decolonization of carriers over 5 days prior to surgery.

RESULTS

Prior to the intervention, we identified 42 deep and/or organ-space PJIs in 8,505 patients undergoing TJR (0.5%). S aureus was the causal microorganism in 28 of 42 (66.6%) cases. During the intervention, 22.5% (424 of 1,883) of patients were S aureus carriers. The PJI rate was similar overall (0.4%, 7 of 1,883; odds ratio, 0.75; 95% confidence interval, 0.34-1.67; P = .58), but there was a significant reduction in S aureus PJI to only 1 case during the intervention (odds ratio, 0.15; 95% confidence interval, 0.004-0.94; P = .039).

CONCLUSIONS

Active screening for S aureus and decolonization of carriers prior to TJR was associated with a reduction in PJI due to S aureus, but no changes in overall PJI rates were observed.

Perioperative Strategies for Surgical Site Infection Prevention

Surgical site infections (SSIs) are some of the most common and costly health care-associated infections. Although the rate of SSIs has declined significantly in the past decade, patient safety remains at risk. Perioperative nurses employ a variety of evidence-based best practices to prevent SSIs and facilitate a safe surgical experience for their patients, including hand hygiene, preoperative patient skin antisepsis, and antimicrobial irrigation. This article explores the causes of SSIs, such as modifiable and nonmodifiable patient factors and preoperative, intraoperative, and postoperative procedural factors, and discusses some of the specific recommended strategies related to the prevention of SSIs that perioperative nurses can initiate in their workplace.

Nasal colonization of Staphylococcus aureus and the risk of surgical site infection after spine surgery: a meta-analysis

BACKGROUND CONTEXT

Nasal colonization of Staphylococcus aureus may increase the risk of surgical site infection (SSI) after spine surgeries, although the results of previous studies were inconsistent.

PURPOSE

To evaluate the influences of nasal colonization of S. aureus, methicillin-susceptible SA, and methicillin-resistant SA (MRSA) on the incidence of SSI after spine surgery.

STUDY DESIGN/SETTING

Systematic review and meta-analysis.

PATIENT SAMPLE

Seven studies including 10,650 patients who underwent nasal swab examination before spine surgeries were included, and 221 patients had nasal colonization of MRSA at baseline.

OUTCOME MEASURES

Association between baseline nasal colonization of S. aureus, MRSA, and SSI after spine surgery.

METHODS

Relevant follow-up studies were identified through systematic searches of the PubMed, Embase, and Cochrane Library databases. A random effects model was applied to pool the results. Subgroup analyses were performed according to whether MRSA decolonization was applied.

RESULTS

During follow-up, a total of 244 SSI events occurred, including 57 MRSA-SSI events. Pooled results showed that nasal S. aureus (risk ratio [RR]=0.75, p=.22) or methicillin-susceptible SA colonization (RR=0.60, p=.22) did not significantly affect the risk of overall SSI after surgeries. However, nasal MRSA colonization was associated with significantly increased risks of overall SSI and MRSA-SSI (RR=2.52 and 6.21, respectively, both p<.001). Interestingly, the associations between nasal MRSA colonization and increased risks of overall and MRSA-SSI remained significant in studies without MRSA decolonization, but became insignificant in studies with MRSA decolonization.

CONCLUSIONS

Nasal MRSA colonization may be associated with increased risks of overall SSI and MRSA-SSI after spine surgeries, and nasal MRSA decolonization may be associated with a reduction of SSI in these patients.

Can nasal Staphylococcus aureus screening and decolonization prior to elective total joint arthroplasty reduce surgical site and prosthesis-related infections? A systematic review and meta-analysis

Background

Nasal Staphylococcus aureus (S. aureus) screening and decolonization has been widely used to reduce surgical site infections (SSIs) prior to total knee and hip arthroplasty (TKA and THA). However, it remains considerably controversial. The aim of this study was to ascertain whether this scheme could reduce SSIs and periprosthetic joint infections (PJIs) following elective primary total joint arthroplasty (TJA).

Methods

A systematic search was performed in MEDLINE, Embase, and the Cochrane Library until October, 2019. Outcomes of interest included SSI, PJI, superficial infection, and different bacterial species that caused infections. Data from eligible studies were then extracted and synthesized. Pooled odds ratios (OR) and 95% confidence intervals (CIs) were calculated. We also performed additional analyses to evaluate whether there were differences in postoperative SSIs caused by S. aureus or other bacteria.

Results

Nine studies were included in our meta-analysis. The pooled data elucidated that nasal S. aureus screening and decolonization dramatically mitigated the risk of SSI, PJI, and superficial infection compared to nondecolonization group. The analysis of bacterial species causing infection also showed that the S. aureus infections postoperative were significantly decreased in the decolonization group. However, there was no statistical difference in the SSI caused by other bacteria between the two groups.

Conclusion

S. aureus screening and decolonization prior to elective primary THA and TKA could significantly decrease the risk of SSI and PJI. However, more robust studies are needed to further evaluate the impact of S. aureus screening and decolonization on infection risk after TJA.

What Prophylactic Antibiotic (Type, Dose and Route of Administration) Should Be Administered Perioperatively for Patients Undergoing Total Ankle Arthroplasty (TAA)?

RECOMMENDATION

The administration of prophylactic antibiotics before total ankle arthroplasty (TAA) potentially reduces the incidence of surgical site infection (SSI) and/or periprosthetic joint infection (PJI). Weight-based (of at least 2 g) cefazolin administered intravenously within 60 minutes before the procedure can be an adequate choice for antibiotic prophylaxis. If the patient has a beta-lactam anaphylaxis, we recommend an appropriate alternative antibiotic effective against Staphylococcus. It is unclear whether prophylaxis should be given as a single dose or as multiple doses.

LEVEL OF EVIDENCE

Strong.

DELEGATE VOTE

Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

Staphylococcus aureus nasal decolonization strategies: a review

Introduction: Staphylococcus aureus (S. aureus) infections are associated with increased morbidity, mortality and health-care costs. Persistent nasal carriage of S. aureus found in 10-30% of the general population, constitutes a risk factor for these infections. Nasal decolonization is one of the used strategies to prevent this risk in some situations. Areas covered: Mupirocin nasal ointment has been used for the nasal decolonization and prevention of staphylococcal infections in various settings like surgeries. However, rising rates of resistance to mupirocin require the development of new decolonization agents. In this review, we will discuss mupirocin, its origins, studies that proved its efficacy and the associated resistance, as well as other decolonization agents under investigation. Expert opinion: As some limitations exist to mupirocin use, further research for alternatives is encouraged. Some old approved antiseptics (chlorhexidine, povidone-iodine) or antibiotics (rifampicin, bacitracin) have been investigated for their efficacy in this indication. Other new agents (tea tree oil, retapamulin, LTX-109, XF-73, phages, lysostaphin, squalamine analogues, etc.) are being studied. Some of them are still in preclinical phases, and others have reached clinical trials, but further research is needed. Special interest should be given to single dose decolonization strategies and to molecules that do not select resistant strains.

Rational Design of Short Peptide Variants by Using Kunitzin-RE, an Amphibian-Derived Bioactivity Peptide, for Acquired Potent Broad-Spectrum Antimicrobial and Improved Therapeutic Potential of Commensalism Coinfection of Pathogens

Commensalism coinfection of pathogens has seriously jeopardized human health. Currently, Kunitzin-RE, as an amphibian-derived bioactivity peptide, is regarded as a potential antimicrobial candidate. However, its antimicrobial properties were unsatisfactory. In this study, a set of shortened variants of Kunitzin-RE was developed by the interception of a peptide fragment and single-site mutation to investigate the effect of chain length, positive charge, hydrophobicity, amphipathicity, and secondary structure on antimicrobial properties. Among them, W8 (AARIILRWRFR) significantly broadened the antimicrobial spectrum and showed the highest antimicrobial activity (GM_all = 2.48 μM) against all the fungi and bacteria tested. Additionally, W8 showed high cell selectivity and salt tolerance in vitro, whereas it showed high effectiveness against mice keratitis cause by infection by C. albicans 2.2086. Additionally, it also had obviously lipopolysaccharide-binding ability and a potent membrane-disruptive mechanism. Overall, these findings contributed to the design of short antimicrobial peptides and to combat the serious threat of commensalism coinfection of pathogens.

Surgical site infection in elective clean and clean-contaminated surgeries in developing countries

BACKGROUND

Surgical site infection (SSI) is both the most frequently studied healthcare-associated infection and the most common healthcare-associated infection in the developing world. A systematic review and meta-analysis was conducted to evaluate the relative size of this burden and to estimate the prevalence of SSI in clean and clean-contaminated surgeries in a large sample of countries in the developing world.

METHODS

A systematic search of the MEDLINE/PubMed, Scopus, and LILACS databases was conducted to identify studies providing the prevalence of SSI in elective clean and clean-contaminated surgeries in 39 countries or regions around the world. Data of interest were limited to publications from January 2000 to December 2017. Studies with information on the number of cases of SSI and number of total elective clean and clean-contaminated surgeries during the same period were included in this evaluation. Studies lacking clear definition of the total number of exposed patients were excluded.

RESULTS

Based on the combined data from the 99 articles evaluated in this analysis, the overall prevalence of SSI in elective clean and clean-contaminated surgeries was estimated to be 6% (95% confidence interval (CI) 5-7%). This increased to 15% (95% CI 6-27%) when considering only those reports with post-discharge surveillance data. The overall prevalence of SSI in Africa/Middle East, Latin America, Asia, and China was 10% (95% CI 6-15%), 7% (95% CI 5-10%), 4% (95% CI 4-5%), and 4% (95% CI 2-6%), respectively. Significant variability in the data was confirmed by both the funnel plot and the Egger test (p=0.008).

CONCLUSIONS

Although the data are variable, it is clear that the incidence of SSI in the developing world is higher than that in the developed world.

Prevention of Infection in Foot and Ankle Surgery

The literature for prevention of surgical infection related primarily to foot and ankle surgery is sparse, with most attention on total joint replacement and abdominal surgery. Attention should be paid to preoperative, intraoperative, and postoperative elements, which can have an effect on the development of postoperative infection. Although antibiotic prophylaxis typically is discussed in isolation, inclusion of this step into the process enhances the overall evaluation of surgery with respect to infection. This evolution provides for better patient outcomes and decreases the likelihood of an infection incurred after foot and ankle surgery.

Decolonization of Staphylococcus aureus in Healthcare: A Dermatology Perspective

The bacterium Staphylococcus aureus is responsible for significant morbidity, mortality, and financial burden in healthcare. It easily colonizes susceptible patients and can cause recurrent infections, especially in populations at risk. In addition to treating sequelae of infections, there is a growing body of literature aimed at decolonizing susceptible patients in order to prevent infection and also to prevent spread. Such strategies are widely employed in surgical, intensive care, and hospitalist fields. Staphylococcus aureus involvement has been implicated in the pathogenesis and persistence of many dermatologic diseases that are treated in the outpatient setting. This review serves to summarize current evidence for the management of Staphylococcus aureus colonized patients, as well as the evidence available for decolonization. We further characterize the role that colonization may play in atopic dermatitis, recurrent infections, hand eczema, cutaneous T-cell lymphoma, and also in surgical infections after Mohs surgery.

The development of a staphylococcus aureus four antigen vaccine for use prior to elective orthopedic surgery

Staphylococcus aureus (S. aureus) is a challenging bacterial pathogen which can cause a range of diseases, from mild skin infections, to more serious and invasive disease including deep or organ space surgical site infections, life-threatening bacteremia, and sepsis. S. aureus rapidly develops resistance to antibiotic treatments. Despite current infection control measures, the burden of disease remains high. The most advanced vaccine in clinical development is a 4 antigen S. aureus vaccine (SA4Ag) candidate that is being evaluated in a phase 2b/3 efficacy study in patients undergoing elective spinal fusion surgery (STaphylococcus aureus suRgical Inpatient Vaccine Efficacy [STRIVE]). SA4Ag has been shown in early phase clinical trials to be generally safe and well tolerated, and to induce high levels of bactericidal antibodies in healthy adults. In this review we discuss the design of SA4Ag, as well as the proposed clinical development plan supporting licensure of SA4Ag for the prevention of invasive disease caused by S. aureus in elective orthopedic surgical populations. We also explore the rationale for the generalizability of the results of the STRIVE efficacy study (patients undergoing elective open posterior multilevel instrumented spinal fusion surgery) to a broad elective orthopedic surgery population due to the common pathophysiology of invasive S. aureus disease and commonalties of patient and procedural risk factors for developing postoperative S. aureus surgical site infections.

Mupirocin-resistant Staphylococcus aureus in Africa: a systematic review and meta-analysis

Background

Mupirocin is widely used for nasal decolonization of Staphylococcus aureus to prevent subsequent staphylococcal infection in patients and healthcare personnel. However, the prolonged and unrestricted use has led to the emergence of mupirocin-resistant (mupR) S. aureus. The aim of this systematic review was to investigate the prevalence, phenotypic and molecular characteristics, and geographic spread of mupR S. aureus in Africa.

Methods

We examined five electronic databases (EBSCOhost, Google Scholar, ISI Web of Science, MEDLINE, and Scopus) for relevant English articles on screening for mupR S. aureus from various samples in Africa. In addition, we performed random effects meta-analysis of proportions to determine the pooled prevalence of mupR S. aureus in Africa. The search was conducted until 3 August 2016.

Results

We identified 43 eligible studies of which 11 (26%) were obtained only through Google Scholar. Most of the eligible studies (28/43; 65%) were conducted in Nigeria (10/43; 23%), Egypt (7/43; 16%), South Africa (6/43; 14%) and Tunisia (5/43; 12%). Overall, screening for mupR S. aureus was described in only 12 of 54 (22%) African countries. The disk diffusion method was the widely used technique (67%; 29/43) for the detection of mupR S. aureus in Africa. The mupA-positive S. aureus isolates were identified in five studies conducted in Egypt (n = 2), South Africa (n = 2), and Nigeria (n = 1). Low-level resistance (LmupR) and high-level resistance (HmupR) were both reported in six human studies from South Africa (n = 3), Egypt (n = 2) and Libya (n = 1). Data on mupR-MRSA was available in 11 studies from five countries, including Egypt, Ghana, Libya, Nigeria and South Africa. The pooled prevalence (based on 11 human studies) of mupR S. aureus in Africa was 14% (95% CI =6.8 to 23.2%). The proportion of mupA-positive S. aureus in Africa ranged between 0.5 and 8%. Furthermore, the frequency of S. aureus isolates that exhibited LmupR, HmupR and mupR-MRSA in Africa were 4 and 47%, 0.5 and 38%, 5 and 50%, respectively.

Conclusions

The prevalence of mupR S. aureus in Africa (14%) is worrisome and there is a need for data on administration and use of mupirocin. The disk diffusion method which is widely utilized in Africa could be an important method for the screening and identification of mupR S. aureus. Moreover, we advocate for surveillance studies with appropriate guidelines for screening mupR S. aureus in Africa.

Evaluation of Staphylococcus aureus eradication therapy in orthopaedic surgery

PURPOSE

Despite WHO recommendations, there is currently no national screening and eradication policy for the detection of methicillin-sensitive Staphylococcus aureus (MSSA) in the UK prior to elective orthopaedic surgery. This study aimed to evaluate the effectiveness of current standard methicillin-resistant S. aureus (MRSA) eradication therapies in the context of S. aureus (both MRSA and MSSA) decolonization in an elective orthopaedic population.

METHODOLOGY

A total of 100 patients awaiting joint replacement surgery who were positive for S. aureus on PCR nasal screening underwent the current standard MRSA pre-operative decolonization regimen for 5 days. Prior to commencement of the eradication therapy, swabs of the anterior nares, throat and perineum were taken for culture. Further culture swabs were taken at 48-96 h following treatment, at hospital admission for surgery and at hospital discharge. Following the completion of treatment, patients were asked to provide feedback on their experience using Likert rating scales. The primary outcome of this study was S. aureus clearance 48-96 h following eradication treatment.Results/Key Findings. Clearance of S. aureus 48-96 h following treatment was 94 % anterior nares, 66 % throat and 88 % groin. Mean completion with nasal mupirocin was 98 %. There was no statistically significant recolonization effect between the end of the eradication treatment period and the day of surgery (P>0.05) at a median time of 10 days.

CONCLUSION

Current MRSA decolonisation regimens are well tolerated and effective for MSSA decolonization for the anterior nares and groin. The decolonization effect is preserved for at least 10 days following treatment.

Methicillin-Resistant Staphylococcus aureus Nasal Swab and Suction Drain Tip Cultures in 4573 Spinal Surgeries: Efficacy in Management of Surgical Site Infections

STUDY DESIGN

A retrospective single-center study.

OBJECTIVE

To assess the diagnostic value of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab and suction drain tip cultures.

SUMMARY OF BACKGROUND DATA

The prognostic value of MRSA nasal swab and suction drain tip cultures has not been firmly established in spinal surgery.

METHODS

This study retrospectively included 4573 consecutive patients who underwent spinal surgery between January 2008 and December 2014. Patients diagnosed with infectious disease were excluded. Prophylactic antibiotics were administered intraoperatively and postoperatively for 48 hours. MRSA nasal swab cultures were taken from all patients before surgery. Drains were removed when the volume of postoperative fluid drainage was less than 50 mL in the preceding 24 hours and cultures were made. Surgical site infection (SSI) was defined according to Centers for Disease Control and Prevention criteria.

RESULTS

SSI was identified in 94 cases (2.1%) and bacteria were isolated in 87 cases (92.6%). Positive MRSA nasal swab cultures were identified in 49 cases (1.1%). There was no significant difference in the SSI positivity rate between the MRSA nasal swab culture (+) and (-) groups. Positive drain tip cultures were found in 382 cases (8.4%), 28 of which developed SSI. There was a significant difference in the SSI positivity rate between the drain tip culture (+) and (-) groups. The sensitivity of drain tip culture was 29.8% and the specificity was 92.1%. In 16 of the 28 patients in the SSI (+) group with positive drain cultures, the same bacteria were isolated from the surgical site, giving a bacteria matching rate of 57.1%.

CONCLUSION

MRSA nasal swab and drain tip cultures were not useful for predicting SSI. However, drain tip culture had a high positivity rate in the SSI group and the coincidence rate for the causative pathogen was relatively high.

LEVEL OF EVIDENCE

4.

Surgical site infection in overweight and obese Total Knee Arthroplasty patients

Purpose

This aim of this study was to evaluate the rate of surgical site infection (SSI) in patients undergoing Total Knee Arthroplasty (TKA), to improve our understanding of the associations between infection rate and obesity.

Methods

Data was reviewed for 839 primary TKA procedures performed at a National Arthroplasty Centre over one year (April 2007-March 2008). SSI data was collected at 30 days and one year post-operatively. Patients were grouped guided by the WHO classifications of obesity; normal (BMI < 25.0), overweight (BMI 25.00-29.99), obese class I (BMI 30.00-34.99), obese class II (BMI 35.00-39.99), obese class III (BMI ≥ 40.00). Statistical significance was assessed by Fisher's Exact Test.

Results

When grouped by BMI, 30.9% of patients were obese class I, 19.0% obese class II and 8.7% obese class III. Of the total cohort, 22 patients (2.6%) had superficial SSI and 13 (1.5%) had deep SSI. When comparing the obese class III cohort to all other cohorts (non-obese class III), the odds ratios for superficial SSI was 4.20 (95% CI [1.59, 11.09]; p = 0.009) and deep SSI was 6.97 (95% CI [2.22, 21.89]; p = 0.003). In the obese class III cohort, superficial SSI rate was higher in females (8.9%) than males (5.9%), yet deep SSI demonstrated the opposite, with a higher occurrence in males (11.8%) compared to females (5.4%).

Conclusion

This study suggests that obese class III TKA patients are at increased odds of superficial and deep SSI compared to other BMI cohorts. Interestingly, male obese class III patients demonstrated a higher rate of deep infection compared to their female counterparts. However, it must be noted that study findings are limited as confounders were unable to be accounted for in this retrospective study design.

Underestimation of Staphylococcus aureus (MRSA and MSSA) carriage associated with standard culturing techniques: One third of carriers missed

OBJECTIVES

Nasal carriers of Staphylococcus (S.) aureus (MRSA and MSSA) have an increased risk for healthcare-associated infections. There are currently limited national screening policies for the detection of S. aureus despite the World Health Organization's recommendations. This study aimed to evaluate the diagnostic performance of molecular and culture techniques in S. aureus screening, determine the cause of any discrepancy between the diagnostic techniques, and model the potential effect of different diagnostic techniques on S. aureus detection in orthopaedic patients.

METHODS

Paired nasal swabs for polymerase chain reaction (PCR) assay and culture of S. aureus were collected from a study population of 273 orthopaedic outpatients due to undergo joint arthroplasty surgery.

RESULTS

The prevalence of MSSA nasal colonization was found to be between 22.4% to 35.6%. The current standard direct culturing methods for detecting S. aureus significantly underestimated the prevalence (p = 0.005), failing to identify its presence in approximately one-third of patients undergoing joint arthroplasty surgery.

CONCLUSION

Modelling these results to national surveillance data, it was estimated that approximately 5000 to 8000 S. aureus surgical site infections could be prevented, and approximately $140 million to $950 million (approximately £110 million to £760 million) saved in treatment costs annually in the United States and United Kingdom combined, by using alternative diagnostic methods to direct culture in preoperative S. aureus screening and eradication programmes.Cite this article: S. T. J. Tsang, M. P. McHugh, D. Guerendiain, P. J. Gwynne, J. Boyd, A. H. R. W. Simpson, T. S. Walsh, I. F. Laurenson, K. E. Templeton. Underestimation of Staphylococcus aureus (MRSA and MSSA) carriage associated with standard culturing techniques: One third of carriers missed. Bone Joint Res 2018;7:79-84. DOI: 10.1302/2046-3758.71.BJR-2017-0175.R1.

Staphylococcus epidermidis isolates from nares and prosthetic joint infections are mupirocin susceptible

The objective of the present study was to investigate the antibiotic susceptibility including mupirocin among Staphylococcus. epidermidis isolated from prosthetic joint infections (PJIs) (n=183) and nasal isolates (n=75) from patients intended to undergo prosthetic joint replacements. Susceptibility to mupirocin (used for eradication of nasal carriership of Staphylococcus aureus) was investigated by gradient test, and susceptibility to various other antimicrobial agents was investigated by disc diffusion test. All isolates, except three from PJIs and one from the nares, were fully susceptible to mupirocin. Multi-drug resistance (≥3 antibiotic classes) was found in 154/183 (84.2%) of the PJI isolates but only in 2/75 (2.7%) of the nares isolates, indicating that S. epidermidis causing PJIs do not originate from the nares.

Use of surveillance data to calculate the sample size and the statistical power of randomized clinical trials testing Staphylococcus aureus vaccine efficacy in orthopedic surgery

BACKGROUND

Patients undergoing primary total hip arthroplasty (THA) would be a worthy population for anti-staphylococcal vaccines. The objective is to assess sample size for significant vaccine efficacy (VE) in a randomized clinical trial (RCT).

METHODS

Data from a surveillance network of surgical site infection in France between 2008 and 2011 were used. The outcome was S. aureus SSI (SASSI) within 30 days after surgery. Statistical power was estimated by simulations repeated for theoretical VE ranging from 20% to 100% and for sample sizes from 250 to 8000 individuals per arm.

RESULTS

18,688 patients undergoing THA were included; 66 (0.35%) SASSI occurred. For a 1% SASSI rate, the sample size would be at least 1316 patients per arm to detect significant VE of 80% with 80% power.

CONCLUSION

Simulations with real-life data from surveillance of hospital acquired infections allow estimation of power for RCT and sample size to reach the required power.

Prevalence and correlates of MRSA and MSSA nasal carriage at a Ugandan regional referral hospital

Background

Despite increasing antimicrobial resistance globally, data are lacking on prevalence and factors associated with Staphylococcus aureus (SA) and MRSA carriage in resource-limited settings.

Objectives

To determine the prevalence of SA and MRSA nasal carriage and factors associated with carriage among Ugandan regional referral hospital patients.

Methods

We enrolled a cross-section of 500 adults, sampling anterior nares for SA and MRSA carriage using Cepheid Xpert SA Nasal Complete.

Results

Mean age was 37 years; 321 (64%) were female and 166 (33%) were HIV infected. Overall, 316 (63%) reported risk factors for invasive SA infection; 368 (74%) reported current antibiotic use. SA was detected in 29% and MRSA in 2.8%. MRSA and MSSA carriers were less likely than SA non-carriers to be female (50% and 56% versus 68%, P  = 0.03) or to have recently used β-lactam antibiotics (43% and 65% versus 73%, P  = 0.01). MRSA carriers were more likely to have open wounds than MSSA carriers and SA non-carriers (71% versus 27% and 40%, P  = 0.001) and contact with pigs (21% versus 2% and 6%, P  = 0.008). MRSA carriage ranged from 0% of HIV clinic participants to 8% of inpatient surgical ward participants ( P  =   0.01). In multivariable logistic regression analysis, male sex was independently associated with SA carriage (OR 1.68, 95% CI 1.12-2.53, P  =   0.01) and recent β-lactam antibiotic use was associated with reduced odds of SA carriage (OR 0.61, 95% CI 0.38-0.97, P  =   0.04).

Conclusions

MRSA nasal carriage prevalence was low and associated with pig contact, open wounds and surgical ward admission, but not with HIV infection.

Povidone-Iodine-Based Solutions for Decolonization of Nasal Staphylococcus aureus: A Randomized, Prospective, Placebo-Controlled Study

BACKGROUND

Nasal Staphylococcus aureus decolonization reduces the risk of surgical site infections after orthopedic procedures. Povidone-iodine (PI)-based solutions have shown promising results in bacteria decolonization. The unique physiology of the nose may pose challenges for the bioactivity profiles of PI solutions. This study compared the antibacterial efficacy of an off-the-shelf PI product with a specifically manufactured PI-based skin and nasal antiseptic (SNA).

METHODS

This randomized, placebo-controlled study was conducted at a single institution between April 2014 and July 2015. Four hundred and twenty-nine patients undergoing primary or revision total joint arthroplasty, femoroacetabular osteoplasty, pelvic osteotomy, or total shoulder arthroplasty were included. 10% off-the-shelf PI, 5% PI-based SNA, or saline (placebo) were used for nasal decolonization. Baseline cultures were taken immediately preoperatively, followed by treatment of both nares twice for 2 minutes with 4 applicators. Reculturing of the right nostril occurred at 4 hours and the left at 24 hours.

RESULTS

Ninety-five of the 429 patients (22.1%) had a positive culture result for S. aureus; 13 (3.03%) were methicillin-resistant S. aureus. Of these 95, 29 were treated with off-the-shelf PI, 34 with SNA, and 32 with saline swabs. At 4 hours post-treatment, S. aureus culture was positive in 52% off-the-shelf PI patients, 21% SNA patients, and 59% saline patients. After 24 hours posttreatment, S. aureus culture was positive in 72% off-the-shelf PI patients, 59% SNA patients, and 69% saline group. SNA was significantly more effective at decolonizing S. aureus over the 4-hour time interval (P = .003); no significant difference was observed over the 24-hour time interval between the 3 groups.

CONCLUSION

A single application of PI-based SNA before surgery may be effective in eliminating nasal S. aureus in over two-thirds of patients. Off-the-shelf PI swabs were not as effective at 4 hours as the specifically manufactured product for S. aureus decolonization.

Elucidation of the relative and absolute stereochemistry of the kalimantacin/batumin antibiotics

A multidisciplinary approach combining natural product degradation, fragment synthesis, bioinformatics and NMR spectroscopy was used.

Kalimantacin A and batumin exhibit potent and selective antibiotic activity against Staphylococcus species including MRSA. Both compounds are formed via a hybrid polyketide synthase/non-ribosomal peptide synthetase (PKS-NRPS) biosynthetic pathway and from comparison of the gene clusters it is apparent that batumin from Pseudomonas batumici and kalimantacin from P. fluorescens are the same compound. The linear structure of this unsaturated acid was assigned by spectroscopic methods, but the relative and absolute stereochemistry of the five stereocentres remained unknown. Herein we describe isolation of kalimantacin A and two further metabolites 17,19-diol 2 and 27-descarbomyl hydroxyketone 3 from cultures of P. fluorescens. Their absolute and relative stereochemistries are rigorously determined using a multidisciplinary approach combining natural product degradation and fragment synthesis with bioinformatics and NMR spectroscopy. Diol 2 has the 5R, 15S, 17S, 19R, 26R, 27R configuration and is the immediate biosynthetic precursor of the bioactive kalimantacin A formed by oxidation of the 17-alcohol to the ketone.

Screening for nasal carriage of Staphylococcus aureus among patients scheduled to undergo orthopedic surgery: Incidence of surgical site infection by nasal carriage

BACKGROUND

Staphylococcus aureus (S. aureus), including MRSA, is considered to be the leading cause of surgical site infection (SSI) after orthopedic surgery. We screened for nasal carriers of S. aureus among patients who were scheduled to undergo orthopedic surgery at our hospital to reveal the effect of nasal S. aureus carriage on SSI. Our study design clearly has the intent of finding S. aureus nasal carriage and eradicating MRSA when found, and this strategy is to verify whether it's effective for preventing orthopedic surgical infections.

METHODS

Subjects were 4148 patients who underwent preoperative screening for nasal carrier and subsequently underwent orthopedic surgery during a 7-year period between April 2007 and March 2014. The incidence of SSI among patients who were operated in our department was investigated, and the rates were compared between patients with and without nasal carriage to reveal the effect of preoperative nasal carriage on SSI.

RESULTS

In total, 1036 patients were nasal carriers of S. aureus (carriage rate, 25.0%), whereas 140 patients carried MRSA (carriage rate, 3.4%). SSI developed in 24 patients [incidence, 0.58% (24/4148)] consisting of 12 non-carriers [0.39% (12/3112)] and 12 carriers [1.16% (12/1036)] with a significant difference in the incidence between the groups. Among 24 cases of SSI, more than half (13 cases) were caused by bacterial species other than S. aureus or those that could not be detected by the tests used. Only 7 patients out of 24 SSI patients, S. aureus was the bacterium detected in preoperative nasal cultures and the causal bacterium for SSI (concordance rate of 29.2%).

CONCLUSIONS

It was difficult to reduce the incidence rate of SSI in eradication group to the same level as nasal culture negative group. However, nasal carriage of S. aureus or MRSA may be a risk factor for SSI in orthopedic surgery.

Nasal decontamination for the prevention of surgical site infection in Staphylococcus aureus carriers

BACKGROUND

Surgical site infection rates in the month following surgery vary from 1% to 5%. Due to the large number of surgical procedures conducted annually, the costs of these surgical site infections (SSIs) can be considerable in financial and social terms. Nasal decontamination using antibiotics or antiseptics is performed to reduce the risk of SSIs by preventing organisms from the nasal cavity being transferred to the skin where a surgical incision will be made. Staphylococcus aureus (S aureus) colonises the nasal cavity and skin of carriers and can cause infection in open or unhealed surgical wounds. S aureus is the leading nosocomial (hospital-acquired) pathogen in hospitals worldwide. The potential effectiveness of nasal decontamination of S aureus is thought to be dependent on both the antibiotic/antiseptic used and the dose of application; however, it is unclear whether nasal decontamination actually reduces postoperative wound infection in S aureus carriers.

OBJECTIVES

To assess the effects of nasal decontamination on preventing surgical site infections (SSIs) in people who are S aureus carriers undergoing surgery.

SEARCH METHODS

In September 2016 we searched the Cochrane Wounds Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library), Ovid MEDLINE, Ovid MEDLINE (In-Process & Other Non-Indexed Citations), Ovid Embase, and EBSCO CINAHL Plus. We also searched three clinical trial registries and the references of included studies and relevant systematic reviews. There were no restrictions based on language, date of publication or study setting.

SELECTION CRITERIA

Randomised controlled trials (RCTs) which enrolled S aureus carriers with any type of surgery and assessed the use of nasal decontamination with antiseptic/antibiotic properties were included in the review.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, risk of bias assessment and GRADE assessment.

MAIN RESULTS

We located two studies (291 participants) for inclusion in this review. The trials were clinically heterogeneous with differences in duration of follow-up, and nasal decontamination regimens. One study compared mupirocin (2% contained in a base of polyethylene glycol 400 and polyethylene glycol 3350) with a placebo in elective cardiac surgery patients; and one study compared Anerdian (iodine 0.45% to 0.57% (W/V), chlorhexidine acetate 0.09% to 0.11% (W/V)) with no treatment also in cardiac surgery patients. The trials reported limited outcome data on SSI, adverse events and secondary outcomes (e.g. S aureus SSI, mortality). Mupirocin compared with placeboThis study found no clear difference in SSI risk following use of mupirocin compared with placebo (1 trial, 257 participants); risk ratio (RR) 1.60, 95% confidence interval (CI) 0.79 to 3.25 based on 18/130 events in the mupirocin group and 11/127 in the control group; low-certainty evidence (downgraded twice due to imprecision). Anerdian compared with no treatmentIt is uncertain whether there is a difference in SSI risk following treatment with Anerdian compared with no treatment (1 trial, 34 participants); RR 0.89, 95% CI 0.06 to 13.08 based on 1/18 events in the Anerdian group and 1/16 in the control group; very low certainty evidence (downgraded twice due to imprecision and once due to risk of bias).

AUTHORS' CONCLUSIONS

There is currently limited rigorous RCT evidence available regarding the clinical effectiveness of nasal decontamination in the prevention of SSI. This limitation is specific to the focused question our review addresses, looking at nasal decontamination as a single intervention in participants undergoing surgery who are known S aureus carriers. We were only able to identify two studies that met the inclusion criteria for this review and one of these was very small and poorly reported. The potential benefits and harms of using decontamination for the prevention of SSI in this group of people remain uncertain.

Short-term increase in prevalence of nasopharyngeal carriage of macrolide-resistant Staphylococcus aureus following mass drug administration with azithromycin for trachoma control

Background

Mass drug administration (MDA) with azithromycin is a corner-stone of trachoma control however it may drive the emergence of antimicrobial resistance. In a cluster-randomized trial (Clinical trial gov NCT00792922), we compared the reduction in the prevalence of active trachoma in communities that received three annual rounds of MDA to that in communities that received a single treatment round. We used the framework of this trial to carry out an opportunistic study to investigate if the increased rounds of treatment resulted in increased prevalence of nasopharyngeal carriage of macrolide-resistant Staphylococcus aureus. Three cross-sectional surveys were conducted in two villages receiving three annual rounds of MDA (3 × treatment arm). Surveys were conducted immediately before the third round of MDA (CSS-1) and at one (CSS-2) and six (CSS-3) months after MDA. The final survey also included six villages that had received only one round of MDA 30 months previously (1 × treatment arm).

Results

In the 3 × treatment arm, a short-term increase in prevalence of S. aureus carriage was seen following MDA from 24.6% at CSS-1 to 38.6% at CSS-2 (p < 0.001). Prevalence fell to 8.8% at CSS-3 (p < 0.001). A transient increase was also seen in prevalence of carriage of azithromycin resistant (Azm^R) strains from 8.9% at CSS-1 to 34.1% (p < 0.001) in CSS-2 and down to 7.3% (p = 0.417) in CSS-3. A similar trend was observed for prevalence of carriage of macrolide-inducible-clindamycin resistant (iMLS_B) strains. In CSS-3, prevalence of carriage of resistant strains was higher in the 3 × treatment arm than in the 1 × treatment (Azm^R 7.3% vs. 1.6%, p = 0.010; iMLS_B 5.8% vs. 0.8%, p < 0.001). Macrolide resistance was attributed to the presence of msr and erm genes.

Conclusions

Three annual rounds of MDA with azithromycin were associated with a short-term increase in both the prevalence of nasopharyngeal carriage of S. aureus and prevalence of carriage of Azm^R and iMLS_BS. aureus.

Trial registration

This study was ancillary to the Partnership for the Rapid Elimination of Trachoma, ClinicalTrials.gov NCT00792922, registration date November 17, 2008.

Total knee arthroplasty and infection: how surgeons can reduce the risks

Total joint arthroplasty (TJA) is one of the most common orthopaedic procedures. Nevertheless, several complications can lead to implant failure.

Peri-prosthetic joint infections (PJI) certainly represent a significant challenge in TJA, constituting a major cause of prosthetic revision. The surgeon may have an important role in reducing the PJI rate by limiting the impact of significant risk factors associated to either the patient, the operative environment or the post-operative care.

In the pre-operative period, several preventive measures may be adopted to manage reversible medical comorbidities. Other recognised pre-operative risk factors are urinary tract infections, intra-articular corticosteroid injections and nasal colonisation with Staphylococcus (S.) aureus, particularly the methicillin-resistant strain (MRSA).

In the intra-operative setting, protective measures for PJI include antibiotic prophylaxis, surgical-site antisepsis and use of pre-admission chlorhexidine washing and pulsed lavage during surgery. In this setting, the use of plastic adhesive drapes and sterile stockinette, as well as using personal protection systems, do not clearly reduce the risk of infection. On the contrary, using sterile theatre light handles and splash basins as well as an increased traffic in the operating room are all associated with an increased risk for PJI.

In the post-operative period, other infections causing transient bacteraemia, blood transfusion and poor wound care are considered as risk factors for PJI.

Cite this article: Ratto N, Arrigoni C, Rosso F, Bruzzone M, Dettoni F, Bonasia DE, Rossi R. Total knee arthroplasty and infection: how surgeons can reduce the risks. EFORT Open Rev 2016;1: 339-344 DOI: 10.1302/2058-5241.1.000032.