Biofilm dispersal of community‐associated methicillin‐resistant Staphylococcus aureus on orthopedic implant material

Orthopedic implant‐related bacterial infections are associated with high morbidity that may lead to limb amputation and exert significant financial burden on the healthcare system. Staphylococcus aureus is a dominant cause of these infections, and increased incidence of community‐associated methicillin‐resistant S. aureus (CA‐MRSA) is being reported. The ability of S. aureus to attach to the foreign body surface and develop a biofilm is an important determinant of resistance to antibiotic prophylaxis. To gain insight on CA‐MRSA biofilm properties, USA300 biofilm maturation and dispersal was examined, and these biofilms were found to exhibit pronounced, quorum‐sensing mediated dispersal from a glass surface. For comparison of biofilm maturation on different surface chemistries, USA300 biofilm growth was examined on glass, polycarbonate, and titanium, and minimal differences were apparent in thickness, total biomass, and substratum coverage. Importantly, USA300 biofilms grown on titanium possessed a functional dispersal mechanism, and the dispersed cells regained susceptibility to rifampicin and levofloxacin treatment. The titanium biofilms were also sensitive to proteinase K and DNaseI, suggesting the matrix is composed of proteinaceous material and extracellular DNA. These studies provide new insights on the properties of CA‐MRSA biofilms on implant materials, and indicate that quorum‐sensing dispersion could be an effective therapeutic strategy. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:55–61, 2010     

Passive immunization with anti‐glucosaminidase monoclonal antibodies protects mice from implant‐associated osteomyelitis by mediating opsonophagocytosis of Staphylococcus aureus megaclusters

Towards the development of a methicillin‐resistant Staphylococcus aureus (MRSA) vaccine we evaluated a neutralizing anti‐glucosaminidase (Gmd) monoclonal antibody (1C11) in a murine model of implant‐associated osteomyelitis, and compared its effects on LAC USA300 MRSA versus a placebo and a Gmd‐deficient isogenic strain (ΔGmd). 1C11 significantly reduced infection severity, as determined by bioluminescent imaging of bacteria, micro‐CT assessment of osteolysis, and histomorphometry of abscess numbers (p < 0.05). Histology also revealed infiltrating macrophages, and the complete lack of staphylococcal abscess communities (SAC), in marrow abscesses of 1C11 treated mice. In vitro, 1C11 had no direct effects on proliferation, but electron microscopy demonstrated that 1C11 treatment phenocopies ΔGmd defects in binary fission. Moreover, addition of 1C11 to MRSA cultures induced the formation of large bacterial aggregates (megaclusters) that sedimented out of solution, which was not observed in ΔGmd cultures or 1C11 treated cultures of a protein A‐deficient strain (ΔSpa), suggesting that the combined effects of Gmd inhibition and antibody‐mediated agglutination are required. Finally, we demonstrated that macrophage opsonophagocytosis of MRSA and megaclusters is significantly increased by 1C11 (p < 0.01). Collectively, these results suggest that the primary mechanism of anti‐Gmd humoral immunity against MRSA osteomyelitis is macrophage invasion of Staphylococcal abscess communities (SAC) and opsonophagocytosis of megaclusters. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1389–1396, 2014.     

Methicillin Resistant <Emphasis Type="Italic">S. aureus</Emphasis> in Human and Bovine Mastitis

Staphylococcus aureus is a ubiquitous organism that causes a variety of diseases including mastitis in cattle and humans. High-level resistance of S. aureus to β-lactams conferred by a mecA gene encoding a modified penicillin binding protein (PBP2a) was first observed in the early 1960’s. These methicillin resistant S. aureus (MRSA) have been responsible for both hospital acquired infections (HA-MRSA) and, more recently, community acquired MRSA (CA-MRSA). A small number of human MRSA mastitis cases and outbreaks in maternity or neonatal units have been reported which are generally the result of CA-MRSA. The establishment of the sequence type 398 (ST398) in farm animals, primarily pigs, in the early 2000’s has provided a reservoir of infection for humans and dairy cattle, particularly in continental Europe, described as livestock-associated MRSA (LA-MRSA). Prior to the emergence of ST398 there were sporadic reports of MRSA in bovine milk and cases of mastitis, often caused by strains from human associated lineages. Subsequently, there have been several reports describing bovine udder infections caused by ST-398 MRSA. Recently, another group of LA-MRSA strains was discovered in humans and dairy cattle in Europe. This group carries a divergent mecA gene and includes a number of S. aureus lineages (CC130, ST425, and CC1943) that were hitherto thought to be bovine-specific but are now also found as carriage or clinical isolates in humans. The emergence of MRSA in dairy cattle may be associated with contact with other host species, as in the case of ST398, or with the exchange of genetic material between S. aureus and coagulase negative Staphylococcus species, which are the most common species associated with bovine intramammary infections and commonly carry antimicrobial resistance determinants.     

Methicillin‐Resistant Staphylococcus aureus: An Emerging Pathogen of Pets in Egypt with a Public Health Burden

Community‐acquired methicillin‐resistant Staphylococcus aureus (CA‐MRSA) has emerged to be a pathogen of public health burden causing infections with significant concern. This study was conducted to investigate methicillin‐resistant Staphylococcus aureus (MRSA) infection in pet dogs and cats as an emerging zoonosis that could be disseminated in the community. A total of 184 (nasal, oral, ear and wound) swabs were collected from 70 pet dogs and 48 pet cats, whereas 50 nasal and oral swabs were collected from 28 apparently healthy companion persons in intimate contact with pets and without history of hospitalization. All samples were cultured for the isolation and identification of Staphylococcus aureus using selective media, biochemical and serological tests, while isolates were identified as MRSA after antimicrobial susceptibility testing and determination of the MIC. PCR was applied using specific primers to confirm MRSA. Three MRSA isolates have been recovered from two dogs of 70 (2.9%) and one isolate from 28 examined persons (3.6%), while none of the examined cats yielded MRSA. Furthermore, we found that two MRSA isolates recovered from one diseased dog seemed to be hospital‐associated methicillin‐resistant Staphylococcus aureus (HA‐MRSA), whereas the other dog isolate as well as the human isolate were considered as community‐acquired (CA‐MRSA). The occurrence of MRSA in apparently healthy and/or diseased pet dogs makes it an emerging veterinary pathogen which could be considered a public health burden if it is disseminated in our community outside hospitals.     

Methicillin‐resistant Staphylococcus aureus in solid organ transplantation—Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the American Society of Transplantation Infectious Diseases Community of Practice review the epidemiology, diagnosis, prevention, and management of methicillin‐resistant Staphylococcus aureus (MRSA) infections in solid organ transplantation. Despite an increasing armamentarium of antimicrobials active against MRSA, improved diagnostic tools, and overall declining rates of infection, MRSA infections remain a substantial cause of morbidity and mortality in solid organ transplant recipients. Pre‐ and post‐transplant MRSA colonization is a significant risk factor for post‐transplant MRSA infection. The preferred initial treatment of MRSA bacteremia remains vancomycin. Hand hygiene, chlorhexidine bathing in the ICU, central‐line bundles that focus on reducing unnecessary catheter use, disinfection of patient equipment, and the environment along with antimicrobial stewardship are all aspects of an infection prevention approach to prevent MRSA transmission and decrease healthcare‐associated infections.     

Identification and molecular characterization of Staphylococcus aureus and multi‐drug resistant MRSA from monkey faeces in China

Staphylococcus aureus is a commensal bacterium and an important opportunistic pathogen in humans and animals. The increase in multi‐drug resistant (MDR) strains of S. aureus is a growing concern due to their impact on animal health and potential for zoonotic transmission. Increasing evidence has shown that MRSA could be transmitted by faeces. The present study determined the prevalence, antibiotic resistance profile and genotypic characteristics of S. aureus isolated from monkey faecal samples in China. Thirty‐eight out of 145 (26.21%) macaque faecal samples were S. aureus positive, which eight (5.5%) isolates were identified as MRSA. Antimicrobial susceptibility tests showed that most of the S. aureus isolates were resistant to tetracycline (TE, 44.74%), followed by penicillin (P, 21.05%), cefoxitin (FOX, 21.05%) and ciprofloxacin (CIP, 18.42%). The predominant spa types were t13638 (44.74%) and t189 (13.16%), which are reported to be closely associated with human infections in China. All MRSA isolates belonged to the SCCmecV type, which six of MRSA isolates were ST3268, while the other two isolates belonged to ST4981. This study for the first time describes the prevalence of S. aureus and MRSA in monkey faeces in China, indicating that faeces could be a potential factor of transmitting S. aureus between humans and monkeys.     

Have the Organisms that Cause Breast Abscess Changed With Time?––Implications for Appropriate Antibiotic Usage in Primary and Secondary Care

Abstract: Many patients with breast abscess are managed in primary care. Knowledge of current trends in the bacteriology is valuable in informing antibiotic choices. This study reviews bacterial cultures of a large series of breast abscesses to determine whether there has been a change in the causative organisms during the era of increasing methicillin‐resistant Staphylococcus aureus (MRSA). Analysis was undertaken of all breast abscesses treated in a single unit over 2003 – 2006, including abscess type, bacterial culture, antibiotic sensitivity and resistance patterns. One hundred and ninety cultures were obtained (32.8% lactational abscess, 67.2% nonlactational). 83% yielded organisms. Staphylococcus aureus was the commonest organism isolated (51.3%). Of these, 8.6% were MRSA. Other common organisms included mixed anaerobes (13.7%), and anaerobic cocci (6.3%). Lactational abscesses were significantly more likely to be caused by S. aureus (p < 0.05). Methicillin‐resistant Staphylococcus aureus rates were not statistically different between lactational and nonlactational abscess groups. Appropriate antibiotic choices are of great importance in the community management of breast abscess. Ideally, microbial cultures should be obtained to institute targeted therapy but we recommend the continued use of flucloxacillin with or without metronidazole (or amoxicillin‐clavulanate as a single preparation) as initial empirical therapy.     

Bacteria antibiotic resistance: New challenges and opportunities for implant‐associated orthopedic infections

There has been a dramatic increase in the emergence of antibiotic‐resistant bacterial strains, which has made antibiotic choices for infection control increasingly limited and more expensive. In the U.S. alone, antibiotic‐resistant bacteria cause at least 2 million infections and 23,000 deaths a year resulting in a $55–70 billion per year economic impact. Antibiotics are critical to the success of surgical procedures including orthopedic prosthetic surgeries, and antibiotic resistance is occurring in nearly all bacteria that infect people, including the most common bacteria that cause orthopedic infections, such as Staphylococcus aureus (S. aureus). Most clinical cases of orthopedic surgeries have shown that patients infected with antibiotic‐resistant bacteria, such as methicillin‐resistant S. aureus (MRSA), are associated with increased morbidity and mortality. This paper reviews the severity of antibiotic resistance at the global scale, the consequences of antibiotic resistance, and the pathways bacteria used to develop antibiotic resistance. It highlights the opportunities and challenges in limiting antibiotic resistance through approaches like the development of novel, non‐drug approaches to reduce bacteria functions related to orthopedic implant‐associated infections. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:22–32, 2018.     

Single‐dose bone pharmacokinetics of vancomycin in a porcine implant‐associated osteomyelitis model

The increasing incidence of orthopaedic methicillin‐resistant Staphylococcus aureus (MRSA) infections represents a significant therapeutic challenge. Being effective against MRSA, the role of vancomycin may become more important in the orthopaedic setting in the years to come. Nonetheless, vancomycin bone and soft tissue penetration during infection remains unclear. In eight pigs, implant‐associated osteomyelitis was induced on day 0, using a Staphylococcus aureus strain. Following administration of 1,000 mg of vancomycin on day 5, vancomycin concentrations were obtained with microdialysis for 8 h in the implant bone cavity, in cancellous bone adjacent to the implant cavity, in subcutaneous adipose tissue (SCT) adjacent to the implant cavity, and in healthy cancellous bone and healthy SCT in the contralateral leg. Venous blood samples were also obtained. The extent of infection and inflammation was evaluated by post‐mortem computed tomography scans, C‐reactive protein serum levels and cultures of blood and swabs. In relation to all the implant cavities, bone destruction was found. Ranging from 0.20 to 0.74, tissue penetration, expressed as the ratio of the area under the concentration–time curve from 0 to the last measured value, was incomplete for all compartments except for healthy SCT. The lowest penetration was found in the implant cavity. In conclusion, Staphylococcus aureus implant‐associated osteomyelitis was found to reduce vancomycin bone penetration, especially in the implant cavity. These findings suggest that it may be unsafe to rely solely on vancomycin therapy when treating acute osteomyelitis. Particularly when metaphyseal cavities are present, surgical debridement seems necessary. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1093–1098, 2018.

     

Hyperbaric oxygen therapy in a mouse model of implant‐associated osteomyelitis

Implant associated osteomyelitis (OM) is difficult to treat with antibiotics, and outcomes remain poor. Some reports suggest that hyperbaric oxygen treatment is a safe and effective means of treating OM. We tested this hypothesis in a murine model. Clinical isolates of methicillin‐resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae were used. The mice were infected with each of the three pathogens, treated with 100% oxygen at high pressure, hyperbaric oxygen (HBO), and monitored for the ability of HBO to prevent and/or clear the OM infection. Assessments included bacterial burden of the tibias and lesion scores, as well as receptor activator of NF‐κB ligand (RANKL) and myeloperoxidase (MPO) concentrations. HBO resulted in more severe lesion scores and higher RANKL and MPO concentrations for MRSA. A significant positive correlation was found between RANKL concentration and lesion score. No significant difference was found with HBO in P. aeruginosa infections and K. pneumoniae seems to either not infect bone well or get cleared before establishing an infection. The model is useful for studying OM infections caused by MRSA and P. aeruginosa, but HBO does not appear to be an efficacious treatment of an implant‐associated OM infection. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:203–208, 2012     

Antibacterial Activity of Ag‐Hydroxyapatite Coating Against Hematogenous Infection by Methicillin‐Resistant Staphylococcus aureus in the Rat Femur

Several antibacterial materials have been developed to prevent periprosthetic joint infection and thus prevent serious complications for patients and surgeons. However, no study has addressed the activity of antibacterial materials against hematogenous infection. The present study evaluated the antibacterial activity of a silver‐containing hydroxyapatite‐coated implant against methicillin‐resistant Staphylococcus aureus (MRSA) hematogenous infection. Implants coated with hydroxyapatite and silver‐hydroxyapatite were inserted into rats’ right and left femurs, respectively, after which the animals were infected with S. aureus via a tail vessel. About 10⁷ colony‐forming units was the optimal bacterial number for the establishment of S. aureus hematogenous infection. Bacterial loads and C‐reactive protein in the blood were measured to confirm bacteremia and inflammation. Fourteen days after the infection, bacterial loads were statistically lower in the femurs containing silver‐hydroxyapatite‐coated implants than in those with hydroxyapatite‐coated implants (p = 0.022). Thus, silver‐hydroxyapatite‐coated implants might provide antibacterial activity against MRSA hematogenous infection in the postoperative period. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2655–2660, 2019     

Preoperative methicillin‐resistant Staphylococcus aureus (MRSA) screening: An effective method to control MRSA infections on elective orthopaedics wards

Background: Methicillin‐resistant Staphylococcus aureus (MRSA) infections continue to increase in UK hospitals despite the introduction of various control measures. These infections have serious clinical and economic implications, particularly in relation to elective orthopaedic surgery. Methods: A prospective study was performed from August 2003 to July 2004 to assess the effect of preadmission screening and ‘ring fencing’ of beds on the incidence of infection in an elective orthopaedics unit. Results: The preoperative incidence of MRSA colonization was 2.25% and 53% of these patients had at least one risk factor. There were no postoperative MRSA infections in the ring‐fenced orthopaedic unit. Conclusions: Preoperative screening and ring fencing reduced the MRSA incidence to zero in the operated patients. Mechanisms need to be developed where screening and isolation of MRSA cases can be performed in most, if not all, hospital admissions.     

Increasing the presence of biofilm and healing delay in a porcine model of MRSA‐infected wounds

Data supporting the concept that microbial biofilms are a major cause of non‐healing ulcers remain limited. A porcine model was established where delayed healing resulted from methicillin‐resistant Staphylococcus aureus (MRSA) infection in full‐thickness wounds. At the end of one study a wound remaining open was sampled and a MRSA strain was isolated. This pig‐passaged strain was used as the inoculating strain in several subsequent studies. The resulting MRSA wound infections exhibited a greater, more stable tissue bioburden than seen in studies using the parent strain. Furthermore, wounds infected with the passaged strain experienced a greater delay in healing. To understand whether these changes corresponded to an increased biofilm character of the wound infection, wound biopsy samples from studies using either the parent or passaged MRSA strains were examined microscopically. Evidence of biofilm was observed for both strains, as most samples at a minimum had multiple isolated, dense microcolonies of bacteria. However, the passaged MRSA resulted in bacterial colonies of greater frequency and size that occurred more often in concatenated fashion to generate extended sections of biofilm. These results provide a model case in which increasing biofilm character of a wound infection corresponded with a greater delay in wound healing.     

Epidermal growth factor vs platelet‐rich plasma: Activity against chronic wound microbiota

The objective was to evaluate Staphylococcus aureus and Pseudomonas aeruginosa colonisation of wounds treated with recombinant epidermal growth factor (EGF) and platelet‐rich plasma (PRP); to analyse the susceptibility profiles of S. aureus and P. aeruginosa isolates from wounds treated with EGF and PRP; and to describe the presence of infection in EGF‐treated and PRP‐treated wounds. Experimental study was performed using clinical specimens collected with swabs. Patients were treated with PRP and EGF in the outpatient clinic of a university hospital. Forty‐three isolates were obtained from 31 patients, 41.9% (13/31) of whom had been treated with EGF and 58.0% (18/31) with PRP. Ten of the 43 isolates were identified as S. aureus, 60.0% (6/10) of which were isolated from PRP‐treated wounds. Among the 33 P. aeruginosa isolates, 66.6% (22/33) were isolated from PRP‐treated wounds. Regarding antimicrobial susceptibility, only one strain isolated from an EGF‐treated wound was identified as methicillin‐resistant S. aureus (MRSA). Among the P. aeruginosa isolates, one obtained from a patient treated with EGF was multidrug‐resistant. Patients treated with EGF had no infections during the follow‐up period, and there was a significant difference between the 1st and 12th week in wound infection improvement in patients treated with PRP (P = .0078).     

Protective role of IL‐1β against post‐arthroplasty Staphylococcus aureus infection

MyD88 is an adapter molecule that is used by both IL‐1R and TLR family members to initiate downstream signaling and promote immune responses. Given that IL‐1β is induced after Staphylococcus aureus infections and TLR2 is activated by S. aureus lipopeptides, we hypothesized that IL‐1β and TLR2 contribute to MyD88‐dependent protective immune responses against post‐arthroplasty S. aureus infections. To test this hypothesis, we used a mouse model of a post‐arthroplasty S. aureus infection to compare the bacterial burden, biofilm formation and neutrophil recruitment in IL‐1β‐deficient, TLR2‐deficient and wild‐type (wt) mice. By using in vivo bioluminescence imaging, we found that the bacterial burden in IL‐1β‐deficient mice was 26‐fold higher at 1 day after infection and remained 3‐ to 10‐fold greater than wt mice through day 42. In contrast, the bacterial burden in TLR2‐deficient mice did not differ from wt mice. In addition, implants harvested from IL‐1β‐deficient mice had more biofilm formation and 14‐fold higher adherent bacteria compared with those from wt mice. Finally, IL‐1β‐deficient mice had ～50% decreased neutrophil recruitment to the infected postoperative joints than wt mice. Taken together, these findings suggest a mechanism by which IL‐1β induces neutrophil recruitment to help control the bacterial burden and the ensuing biofilm formation in a post‐surgical joint. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 1621–1626, 2011     

Topical simvastatin promotes healing of Staphylococcus aureus‐contaminated cutaneous wounds

Cutaneous wounds are prompt to be contaminated by bacteria, but the clinical benefits of applying antibiotics and antiseptics in wound management have not been proven. Statins are 3‐hydroxy‐3‐methylglutaryl‐coenzyme A (HMG‐CoA) reductase inhibitors commonly used to lower cholesterol levels. Studies indicated that statins, especially simvastatin, promote wound healing in experimental models. As Staphylococcus aureus is one of the most important microorganism responsible for wound infections, the aims of this study were to characterise the anti‐staphylococcal activity of simvastatin and to evaluate the application of simvastatin as a topical therapy for S. aureus‐contaminated wounds. In the present study, simvastatin was bacteriostatic against S. aureus at sub‐inhibitory concentrations up to 8 hours after exposure. Further increased concentrations of simvastatin above the minimal inhibitory concentration (MIC) did not enhance the growth inhibitory effect. By contrast, the ability of simvastatin to inhibit S. aureus biofilm formation was concentration dependent. Topical application of simvastatin at its MIC against S. aureus accelerated the healing and bacterial clearance of S. aureus‐contaminated wounds in an excisional mice wound model. This effective concentration is well below the safe concentration for topical use. Collectively, topical application of simvastatin has the potential as a novel modality for managing wound infections and promoting wound healing.     

Colonisation with methicillin‐resistant Staphylococcus aureus prior to renal transplantation is associated with long‐term renal allograft failure

Renal transplant recipients are at an increased risk of developing Methicillin‐resistant Staphylococcus aureus due to their immunosuppressed status. Herein, we investigate the incidence of MRSA infection in patients undergoing renal transplantation and determine the effect of MRSA colonisation on renal allograft function and overall mortality. Between January 1st 2007 and December 31st 2012, 1499 consecutive kidney transplants performed in our transplant unit and a retrospective 1:2 matched case‐control study was performed on this patient cohort. The 1‐, 3‐ and 5‐year overall graft survival rates were 100%, 86% and 78%, respectively, in MRSA positive recipients compared with 100%, 100% and 93%, respectively, in the control group (P < 0.05). The 1‐, 3‐ and 5‐year overall patient survival rates were 100%, 97% and 79%, respectively, in MRSA positive recipients compared with 100%, 100% and 95%, respectively, in the control group (P = 0.1). In a multiple logistic regression analysis, colonisation with MRSA pre‐operatively was an independent predictor for renal allograft failure at 5 years (hazard ratio: 4.6, 95% confidence interval: 1–30.7, P = 0.048). These findings demonstrate that the incidence of long‐term renal allograft failure is significantly greater in this patient cohort compared with a matched control population.     

Topical sevoflurane for chronic venous ulcers infected by multi‐drug‐resistant organisms

Several anaesthetic drugs have demonstrated antibacterial properties in vitro. Anaesthetics can primarily affect the cell wall of both susceptible and multi‐resistant bacteria. They may also have a synergistic effect with conventional antibiotics through an unknown mechanism. We present three cases of a chronic venous ulcer infected by multi‐resistant bacteria refractory to conventional systemic antibiotics, including Pseudomonas aeruginosa and methicillin‐resistant Staphylococcus aureus (MRSA). Treatment with topical sevoflurane was performed for 1 month without systemic antibiotics. Patients with an MRSA infection showed progressive improvement with negative culture at the end of the treatment. Multi‐drug‐resistant P. aeruginosa infection persisted at the end of treatment with positive culture. The local adverse events were mild and transient, including heat, pruritus and erythema. Topical sevoflurane may have an antibacterial effect on sensitive and multi‐resistant strains. It can allow more complete surgical cleaning, leaving a cleaner wound with less fibrin and necrotic tissue. This decreases the bacterial colonisation and therefore the infectious risk, the bad smell and the exudation. The simultaneous use of conventional antibiotics and topical sevoflurane can have a synergistic antimicrobial effect.     

Glomerulonephritis induced by methicillin-sensitive <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> infection

A 57-year-old woman developed exacerbation of atopic dermatitis, fever, and nephrotic syndrome with microscopic hematuria. By bacteriological study, methicillin-sensitive Staphylococcus aureus (MSSA) was detected from each culture of pharyngeal mucus, stool, and blood samples. Renal biopsy specimens showed endocapillary proliferative glomerulonephritis with massive IgA deposition in the mesangium and along the capillary loops. After antistaphylococcal therapy with antibiotics, MSSA was negative for each culture and urinary protein decreased. Nine months after the first renal biopsy, a re-biopsy was performed, which revealed apparent disappearance of both endocapillary cell proliferation and IgA deposition. It is known that methicillin-resistant S. aureus (MRSA) infection causes glomerulonephritis through T-cell stimulation by superantigen presented by MRSA. The present results suggest that not only MRSA but also MSSA can cause this type of glomerulonephritis.     

MRSA infections following colorectal surgery in an enhanced recovery programme

Aim The aim of this study was to evaluate the incidence of methicillin‐resistant Staphylococcus aureus (MRSA) infections in a cohort of patients undergoing elective colorectal resections within an enhanced recovery programme. Method A prospective database of all patients undergoing colorectal resections by a single surgical team over a 3.5‐year period was reviewed. Demographics including age, gender, body mass index, American Society of Anesthesiologists classification, type of surgery (abdominal or pelvic) and whether or not the procedure was laparoscopic or open were analysed. All patients were screened preoperatively and postoperatively and on discharge for MRSA. Patients found preoperatively to be MRSA positive were excluded from the study. Results In all, 186 patients underwent colorectal resection over the time reviewed. There were 113 laparoscopic resections, 70 open resections and three laparoscopic converted to open resections. Five patients (2.7%) were found to be MRSA positive postoperatively. All of these had open rather than laparoscopic surgery (P < 0.01). Length of stay for patients that had MRSA infections was significantly longer than those remaining MRSA free (P < 0.05). Conclusion These results suggest that patients who successfully undergo laparoscopic colorectal resections within an enhanced recovery programme have a lower incidence of postoperative MRSA infections.