How Often Do Asymptomatic Healthcare Workers Cause Methicillin-ResistantStaphylococcus aureusOutbreaks? A Systematic Evaluation

Using adenosine triphosphate bioluminescence level monitoring to identify bacterial reservoirs during two consecutive Enterococcus faecium and Staphylococcus capitis nosocomial infection outbreaks at a neonatal intensive care unit

INTRODUCTION

This study aimed to assess the role of adenosine triphosphate (ATP) bioluminescence level monitoring for identifying reservoirs of the outbreak pathogen during two consecutive outbreaks caused by Enterococcus faecium and Staphylococcus capitis at a neonatal intensive care unit (NICU). The secondary aim was to evaluate the long-term sustainability of the infection control measures employed one year after the final intervention measures.

METHODS

Two outbreaks occurred during a 53-day period in two disconnected subunits, A and B, that share the same attending physicians. ATP bioluminescence level monitoring, environmental cultures, and hand cultures from healthcare workers (HCW) in the NICU were performed. Pulsed-field gel electrophoresis (PFGE) typing was carried out to investigate the phylogenetic relatedness of the isolated strains.

RESULTS

Four cases of E. faecium sepsis (patients A-8, A-7, A-9, B-8) and three cases of S. capitis sepsis (patients A-16, A-2, B-8) were diagnosed in six preterm infants over a span of 53 days. ATP levels remained high on keyboard 1 of the main station (2076 relative light unit [RLU]/100 cm2) and the keyboard of bed A-9 (4886 RLU/100 cm2). By guidance with the ATP results, environmental cultures showed that E. faecium isolated from the patients and from the main station's keyboard 1 were genotypically indistinguishable. Two different S. capitis strains caused sepsis in three patients. A total 77.8% (n = 7/9) of S. capitis cultured from HCW's hands were genotypically indistinguishable to the strains isolated from A-2 and A-16. The remaining 22.2% (n = 2/9) were genotypically indistinguishable to patient B-8. Three interventions to decrease the risk of bacterial transmission were applied, with the final intervention including a switch of all keyboards and mice in NICU-A and B to disinfectable ones. Post-intervention prospective monitoring up to one year showed a decrease in blood culture positivity (P = 0.0019) and catheter-related blood stream infection rate (P = 0.016) before and after intervention.

CONCLUSION

ATP monitoring is an effective tool in identifying difficult to disinfect areas in NICUs. Non-medical devices may serve as reservoirs of pathogens causing nosocomial outbreaks, and HCWs' hands contribute to bacterial transmission in NICUs.

Prevalence of methicillin-resistant Staphylococcus aureus carriage among healthcare workers in South Asia in non-outbreak settings: A systematic review and meta-analysis

BACKGROUND

This study aimed to estimate the pooled prevalence and sub-group-specific prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) carrier rate among Healthcare Workers (HCWs) in South Asia.

METHODOLOGY

We considered prospective and cross-sectional studies published in the English language with participants ≥50 by searching different electronic databases to locate the relevant articles that reported the epidemiology of MRSA. The participants were healthy South Asian nationality HCWs (asymptomatic for any infectious disease) of any age and gender with a definitive diagnosis of MRSA carriage. The result was synthesized for the pooled prevalence of MRSA carriers among HCWs using 95% confidence interval (CI) with DerSimonian and Laird random-effects models.

RESULTS

The pooled prevalence of MRSA carriage among HCWs was 9.23% (95%CI; 6.50%, 12.35%) with a range from 0.67% to 36.06%. The prevalence in India, Nepal, Pakistan, Sri Lanka, and Bangladesh was 5.65% (95%CI; 3.65%, 8.03%), 8.83% (95%CI; 6.77%, 11.11%), 17.20% (95%CI; 10.70%, 24.85%), 22.56% (95%CI; 4.93%, 47.83%), and 4.93% (95%CI; 1.88%, 9.20%) respectively. The pooled prevalence of MRSA carriage among nurses and doctors was 8.90% (95%CI; 6.00%, 12.24%) and 6.53% (95%CI; 3.63%, 10.06%) respectively.

CONCLUSION

The findings from our study suggests that if the propagation of MRSA continues, then it can lead to a situation of an outbreak. Hence, proper preventive measures are to be adopted to prevent this outbreak.

Transmission and microevolution of methicillin-resistant Staphylococcus aureus ST88 strain among patients, healthcare workers, and household contacts at a trauma and orthopedic ward

Background

Surgical sites infections (SSIs) caused by Methicillin-resistant Staphylococcus aureus (MRSA) constitute a major clinical problem. Understanding the transmission mode of MRSA is important for its prevention and control.

Aim

We investigated the transmission mode of a MRSA outbreak in a trauma and orthopedic hospital ward.

Methods

Clinical data were collected from patients (n = 9) with MRSA infection in a trauma and orthopedic ward from January 1, 2015 to December 31, 2019. The wards (n = 18), patients (n = 48), medical staff (n = 23), and their households (n = 5) were screened for MRSA. The transmission mode of MRSA isolates was investigated using next-generation sequencing and phylogenetic analyses. The resistance genes, plasmids, and single-nucleotide variants of the isolates were analyzed to evaluate microevolution of MRSA isolates causing SSIs. The MRSA colonization-positive doctor was asked to suspend his medical activities to stop MRSA spread.

Findings

Nine MRSA infected patients were investigated, of which three patients were diagnosed with SSI and had prolonged hospitalization due to the persistent MRSA infection. After screening, MRSA isolates were not detected in environmental samples. The surgeon in charge of the patients with SSI caused by MRSA and his son were positive for MRSA colonization. The MRSA from the son was closely related to the isolates detected in MRSA-induced SSIs patients with 8-9 single-nucleotide variants, while ST88-MRSA isolates with three different spa types were detected in the surgeon's nasal cavity. Comparative genomic analysis showed that ST88-MRSA isolates acquired mutations in genes related to cell wall synthesis, colonization, metabolism, and virulence during their transmission. Suspending the medical activity of this surgeon interrupted the spread of MRSA infection in this ward.

Conclusion

Community-associated MRSA clones can invade hospitals and cause severe postoperative nosocomial infections. Further MRSA surveillance in the households of health workers may prevent the transition of MRSA from colonization to infection.

Genetic characterization of Staphylococcus aureus isolated from Norway rats in Boston, Massachusetts

BACKGROUND

Despite the importance of domesticated animals in the generation and transmission of antibiotic-resistant Staphylococcus aureus, the role of wild animals, specifically rodents, in the ecology of S. aureus remains unclear. We recovered and genotyped S. aureus isolates from wild Norway rats (Rattus norvegicus) in Boston, Massachusetts to examine genetic relationships between common human and animal S. aureus isolates in a large US metropolitan area.

METHODS

We collected and necropsied 63 rats from June 2016 to June 2017. Nasal, foot pad, fur, and fecal swabs were collected. Staphylococcus aureus was isolated using culture-based methods and polymerase chain reaction confirmation. S. aureus isolates were spa typed, tested for antibiotic susceptibility, and whole genome sequenced. Assembled sequences were uploaded to the Comprehensive Antibiotic Resistance Database to identify antibiotic resistance elements. A phylogenetic tree was constructed using the neighbor-joining method with the maximum composite likelihood distance in MEGA7.

RESULTS

We recovered 164 Gram-positive bacterial isolates from Norway rats. Nineteen isolates from eight individual rats were confirmed as S. aureus (prevalence: 12.9% (8/63)). All S. aureus isolates were methicillin-susceptible S. aureus (MSSA), pvl-negative, and resistant to penicillin. Two isolates displayed resistance to erythromycin. Four different S. aureus spa types were detected (t933, t10751, t18202, and t189). Thirteen unique antibiotic resistance elements were identified, and all isolates shared genes mepR, mgrA, arlR, and S. aureus norA. Phylogenetic analysis if the 19 S. aureus isolates revealed they were genetically similar to four clades of S. aureus with similar resistance gene profiles isolated from both human- and animal-derived S. aureus, as well as formed a distinct phylogenetic cluster composed only of rat isolates.

CONCLUSIONS

Wild rodents may serve as a reservoir or vector of antibiotic resistance genes in the urban environment with relevance for human and animal health.

Cumulative Incidence of Methicillin-Resistant Staphylococcus aureus Colonization in Resident Physicians Over Time

Background

Methicillin-resistant Staphylococcus aureus (MRSA) can colonize up to 14.5% of healthcare workers (HCWs). The colonization rate of HCWs or the hospital setting that contributes most to MRSA colonization is less clear. In this study, we studied new resident physicians (PGY-1), as a model for HCWs, to measure their colonization rate and hypothesized that the incidence of colonization would increase during their first year.

Methodology

We prospectively enrolled PGY-1 residents of multiple specialties at three academic medical centers. After obtaining informed consent, PGY-1 residents were tested for MRSA in June 2019 before starting any clinical rotations and then retested every three to four months thereafter. The coronavirus disease 2019 pandemic forced us to end the study early. If MRSA-positive, residents were treated with 2% mupirocin and retested for a cure. For comparison, upper-level residents (PGY-2-5) were also enrolled to obtain a baseline prevalence of colonization.

Results

We enrolled 80 PGY-1 and 81 PGY-2-5 residents in the study. The baseline prevalence of MRSA colonization was 4.94% (4/81) in PGY-2-5 residents and 2.50% (2/80) for new PGY-1 residents; however, this was not statistically significant (p = 0.68). The cumulative yearly incidence of developing MRSA colonization in PGY-1 residents was 4.51%. MRSA colonization was successfully treated in 75% of cases.

Conclusions

PGY-1 residents had a lower MRSA colonization rate compared to PGY-2-5 residents, although this was not statistically significant. PGY-1 residents had a small incidence of developing MRSA colonization while working in the hospital. Further research is needed to determine if this is clinically relevant to HCWs or their patients.

SARS-Coronavirus-2 cases in healthcare workers may not regularly originate from patient care: lessons from a university hospital on the underestimated risk of healthcare worker to healthcare worker transmission

BACKGROUND

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents an unprecedented healthcare challenge. Various SARS-CoV-2 outbreaks in healthcare facilities have been reported. Healthcare workers (HCWs) may play a critical role in the spread of the virus, particularly when asymptomatic. We examined four healthcare-associated outbreaks of SARS-CoV-2 infections that occurred at a university hospital in Berlin, Germany. We aimed to describe and analyze the spread of the virus in order to draw conclusions for effective containment of SARS-CoV-2 in healthcare facilities.

METHODS

Healthcare-associated outbreaks of SARS-CoV-2 infections were defined as two or more laboratory confirmed infections with SARS-CoV-2 where an epidemiological link within the healthcare setting appeared likely. We focused our analysis on one of three sites of the Charité-University Medicine hospital within a 2 month period (March and April 2020).

RESULTS

We observed four healthcare-associated outbreaks of SARS-CoV-2 infections, with a total of 24 infected persons (23 HCWs and one patient). The outbreaks were detected in the departments of nephrology and dialysis (n = 9), anesthesiology (n = 8), surgical pediatrics (n = 4), and neurology (n = 3). Each outbreak showed multiple unprotected contacts between infected HCWs. A combination of contact tracing, testing, physical distancing and mandatory continuous wearing of face masks by all HCWs was able to contain all four outbreaks.

CONCLUSIONS

HCW to HCW transmission represented the likely source of the four outbreaks. Ensuring proper physical distancing measures and wearing of protective equipment, also when interacting with colleagues, must be a key aspect of fighting COVID-19 in healthcare facilities.

Nasal decolonization of Staphylococcus aureus in orthopedic surgeons using mupirocin and chlorhexidine

Nasal mucosa colonization by Staphylococcus aureus is a risk factor for hospital-acquired infections. This study examined the effectiveness of a decolonization strategy on orthopedic surgeons in a teaching hospital. S aureus colonization was detected in 43.2% of the surgeons, 25% of which were methicillin-resistant S aureus strains. Eradication was documented in 61.53% of the subjects who completed the decolonization strategy. Among orthopedic surgeons, mupirocin with or without chlorhexidine decolonization strategies was effective in eradicating S aureus colonization.

Vancomycin intermediate resistant Staphylococcus aureus in the nasal cavity of asymptomatic individuals: a potential public health challenge

Background

The potential of transmitting multidrug resistant Staphylococcus aureus from asymptomatic individuals to healthy individuals could constitute a great challenge to antimicrobial therapy.

Methods

The antibiograms of the S. aureus from asymptomatic individuals were determined by disk diffusion and agar dilution assay techniques with different antibiotics and vancomycin.

Results

Of the 152 S. aureus isolated, (59)38.8% isolates were multi-drug resistant strains. Streptomycin was the most effective and inhibited (135)88.82% of the isolates while ceftazidime inhibited (24)15.8% of the isolates. While (82)54.0% of the isolates inhibited by cefuroxime had resistant colonies within their inhibition zones (Rc) and ofloxacin inhibited (100)65.8% of the isolates without having resistant colonies within the inhibition zones, ceftazidime inhibited (7)4.6% of the isolates with resistant colonies within the inhibition zones. Subjecting the isolates to vancomycin showed that (27)17.8% were resistant to 2 µg/ml, (43)28.3% were resistant to 4 µg/ml and (27)17.8% of the isolates were simultaneously resistant to both concentrations of vancomycin. Although (100)65.8% of the isolates had MAR_index ≥0.2, (52)34.2% of the isolates had MAR_index ≤ 0.2 and (65)428% of the isolates were considered multidrug resistant strains.

Conclusion

The isolation of multi-drug and vancomycin intermediate resistant strains of S. aureus in high percentage, in this study, presents a great threat to clinicians and general populace. The vancomycin intermediate resistant S. aureus (VISA) in asymptomatic individuals could be a critical concern to the therapeutic dilemma to be added to the presence of multi-drug resistance. A more sustainable therapy must be in place to prevent its dissemination or the outbreak of its infection.

Staphylococcus aureus Nasal Colonization: An Update on Mechanisms, Epidemiology, Risk Factors, and Subsequent Infections

Up to 30% of the human population are asymptomatically and permanently colonized with nasal Staphylococcus aureus. To successfully colonize human nares, S. aureus needs to establish solid interactions with human nasal epithelial cells and overcome host defense mechanisms. However, some factors like bacterial interactions in the human nose can influence S. aureus colonization and sometimes prevent colonization. On the other hand, certain host characteristics and environmental factors can predispose to colonization. Nasal colonization can cause opportunistic and sometimes life-threatening infections such as surgical site infections or other infections in non-surgical patients that increase morbidity, mortality as well as healthcare costs.

Nasal Carriage of Methicillin-Resistant Staphylococcus aureus among Health Care Workers in Tertiary and Regional Hospitals in Dar es Salam, Tanzania

Methicillin-resistant Staphylococcus aureus (MRSA) among health care workers (HCWs) increases the risk of spreading the organism in hospital settings. A cross-sectional study was conducted between June and October 2016 among HCWs in tertiary and regional hospitals in Dar es Salaam, Tanzania, to determine the MRSA nasal carriage rate. Nasal swabs were collected from HCWs and cultured on mannitol salt agar. S. aureus was identified based on colonial morphology, Gram staining, catalase, coagulase, and DNase test results. MRSA was detected using the cefoxitin disk. Among 379 HCWs enrolled, 157/379 (41.4%) were colonized with S. aureus, of whom 59 (37.6%) were MRSA carriers giving an overall prevalence of 59/379 (15.6%). MRSA carriage was high among HCWs in Temeke (56.9%) and Amana (37.5%) regional hospitals. A high proportion of MRSA carriage was detected among nurses (35, 45.5%). MRSA isolates showed high resistance toward kanamycin (83.7%), gentamicin (83.1%), ciprofloxacin (71.2%), and trimethoprim-sulphamethoxazole (46.8%) compared to methicillin-sensitive S. aureus isolates (p ≤ 0.001). In conclusion, we found a high nasal carriage of MRSA and resistance to commonly prescribed antimicrobial agents among HCWs. Implementation of infection control measures including contact precautions, urgent reporting of MRSA laboratory results, and routine MRSA screening of HCWs is highly needed to reduce MRSA spreading.

Effectiveness of healthcare worker screening in hospital outbreaks with gram-negative pathogens: a systematic review

Background

Identifying the source of an outbreak is the most crucial aspect of any outbreak investigation. In this review, we address the frequently discussed question of whether (rectal) screening of health care workers (HCWs) should be carried out when dealing with outbreaks caused by gram negative bacteria (GNB).

A systematic search of the medical literature was performed, including the Worldwide Outbreak Database and PubMed. Outbreaks got included if a HCW was the source of the outbreak and the causative pathogen was an Escherichia coli, Klebsiella spp., Enterobacter spp., Serratia spp., Pseudomonas aeruginosa, or Acinetobacter baumannii.

This was true for 25 articles in which there were 1196 (2.1%) outbreaks due to GNB, thereof 14 HCWs who were permanently colonized by the outbreak strain. Rectal screening of HCWs was helpful in only 2 of the 1196 (0.2%) outbreaks. Instead, the hands of HCWs served as a reservoir for the outbreak strain in at least 7 articles – especially when they suffered from onychomycosis or used artificial fingernails or rings.

Conclusion

Due to very weak evidence, we do not recommend rectal screening of HCWs in an outbreak situation with GNB. However, besides a critical review of hand hygiene habits, it might be useful to examine the hands of staff carefully. This measure is cheap, quick to perform, and seems to be quite effective.

Electronic supplementary material

The online version of this article (10.1186/s13756-018-0330-4) contains supplementary material, which is available to authorized users.

Nasal carriage of methicillin-resistant coagulase-negative staphylococci in healthy humans is associated with occupational pig contact in a dose-response manner

This study aimed to explore the association between occupational pig contact and human methicillin-resistant coagulase-negative staphylococci (MRCoNS) carriage. We conducted a cross-sectional study of pig exposed participants and controls in Guangdong, China, using a multi-stage sampling design. Participants provided a nasal swab for MRCoNS analysis and resulting isolates were tested for antibiotic susceptibility. The dose-response relation was examined using log binomial regression or Poisson regression models. The adjusted prevalence of MRCoNS carriage in pig exposed participants was 1.67 times (95% CI: 1.32-2.11) higher than in controls. The adjusted average number of resistance to different antibiotic classes of MRCoNS isolates from pig exposed participants was 1.67 times (95% CI: 1.46-1.91) higher than those from controls. Notably, we found the frequency and duration of occupational pig contact was associated with increased prevalence and increased number of resistance to different antibiotic classes of MRCoNS in a dose-response manner. When examining these relations by MRCoNS species, there was still evidence of similar exposure-response relations. Additionally, the proportion of tetracycline-resistant and tet(M)-containing MRCoNS isolates was significantly higher in pig exposed participants than in controls. These findings suggested a potential transmission of MRCoNS from livestock to humans by occupational livestock contact, and the presence of phenotypic and genotypic tetracycline resistance may aid in the differentiation of animal origins of MRCoNS isolates.

Rapid containment of nosocomial transmission of a rare community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clone, responsible for the Staphylococcal Scalded Skin Syndrome (SSSS)

Background

The aims of this study were to identify the source and the transmission pathway for a Staphylococcal Scalded Skin Syndrome (SSSS) outbreak in a maternity setting in Italy over 2 months, during 2014; to implement appropriate control measures in order to prevent the epidemic spread within the maternity ward; and to identify the Methicillin-Resistant Staphylococcus aureus (MRSA) epidemic clone.

Methods

Epidemiological and microbiological investigations, based on phenotyping and genotyping methods, were performed. All neonates involved in the outbreak underwent clinical and microbiological investigations to detect the cause of illness. Parents and healthcare workers were screened for Staphylococcus aureus to identify asymptomatic carriers.

Results

The SSSS outbreak was due to the cross-transmission of a rare clone of ST5-CA-MRSA-SCCmecV-spa type t311, exfoliative toxin A-producer, isolated from three neonates, one mother (from her nose and from dermatological lesions due to pre-existing hand eczema) and from a nurse (colonized in her nose by this microorganism). The epidemiological and microbiological investigation confirmed these as two potential carriers.

Conclusions

A rapid containment of these infections was obtained only after implementation of robust swabbing of mothers and healthcare workers. The use of molecular methodologies for typing was able to identify all carriers and to trace the transmission.

Nasal carriage of methicillin resistant Staphylococcus aureus among health care workers at Al Shifa hospital in Gaza Strip

Background

Nasal carriage of Staphylococcus aureus among hospital personnel is a common cause of hospital acquired infections. Emergence of drug resistant strains especially methicillin resistant S. aureus (MRSA) is a serious problem in hospital environment. Therefore, the aim of this study was to determine the nasal carriage rate of S. aureus and MRSA among Health Care Workers (HCWs) at Al Shifa Hospital, the major hospital in Gaza Strip.

Methods

A cross sectional study was conducted on 200 HCWs. Nasal swabs were collected during February — April 2015, and cultured on blood and mannitol salt agar. The isolates were identified as S. aureus based on morphology, coagulase test, DNase test and mannitol salt agar fermentation. Disk diffusion antibiotic susceptibility tests were performed according to the guidelines of the Clinical and Laboratory Standards Institute. MRSA were confirmed by detection of the mecA gene by PCR.

Results

Out of the 200 healthcare workers, 62 (31%) carried S. aureus, of which 51 (82.3%) were MRSA. Therefore, 25.5% of all HCWs were identified as MRSA carriers. MRSA carriage rate was highest among nurses (30.4%) whereas the carriage rate among doctors was (16%). The majority of MRSA carriers were workers of internal medicine department and surgical wards (41.3 and 35% respectively). Out of the 51 MRSA isolates identified by oxacillin disc resistance, 40 were confirmed by PCR targeting the mecA gene. Penicillin showed the highest rate of resistance among MRSA and MSSA isolates (100%).

Conclusions

The high rate of nasal MRSA carriage among healthcare workers found in this study is alarming and highlights the need for adjusted infection control measures to prevent MRSA transmission from HCWs to the vulnerable patient.

MRSA Prevalence and Associated Risk Factors among Health-Care Workers in Non-outbreak Situations in the Dutch-German EUREGIO

Preventing the spread of methicillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities is a major infection control target. However, only a few studies have assessed the potential role of healthcare workers (HCWs) for MRSA dissemination. To investigate the MRSA prevalence and the risk factors for MRSA colonization among HCWs, nasopharyngeal swabs were taken between June 2010 and January 2011 from 726 employees from nine acute care hospitals with different care levels within the German part of a Dutch-German border region (EUREGIO). The isolated MRSA strains were investigated using spa typing. The overall MRSA prevalence among HCWs in a non-outbreak situation was 4.6% (33 of 726), and was higher in nurses (5.6%, 29 of 514) than in physicians (1.2%, 1 of 83). Possible risk factors associated with MRSA colonization were a known history of MRSA carriage and the presence of acne. Intensive contact with patients may facilitate MRSA transmission between patients and HCWs. Furthermore, an accumulation of risk factors was accompanied by an increased MRSA prevalence in HCW.

Colonisation with methicillin-resistant Staphylococcus aureus and associated factors among nurses with occupational skin diseases

OBJECTIVES

To evaluate the prevalence of colonisation with methicillin-resistant Staphylococcus aureus (MRSA), associated factors and the effectiveness of decolonisation procedures among nurses with occupational skin diseases (OSD).

METHODS

In a retrospective cohort study, the medical records of 319 nurses from Germany who were screened consecutively for MRSA when participating in a tertiary individual prevention programme (TIP) for severe OSD between July 2009 and December 2014 were evaluated.

RESULTS

90.3% of nurses with severe OSD suffered from hand eczema. 43 were colonised with MRSA on admission (13.5%), mainly in the nose (n=35, 81.4%). However, the hands were affected in more than half of the MRSA carriers (n=24, 55.8%). Risk factors for MRSA colonisation were atopic skin diathesis (OR 2.01, 95% CI 1.03 to 3.92, p=0.049) and presence of atopic dermatitis on other body parts than the hands (OR 4.33, 95% CI 2.23 to 8.43, p<0.001). Hand eczema was significantly more severe in MRSA carriers than in non-carriers (OR 1.23, 95% CI 1.10 to 1.37, p<0.001) and showed a higher prevalence of vesicles, erosions or fissures. MRSA eradication was successful in 67.4% after the first attempt.

CONCLUSIONS

Nurses with OSD have a twofold to threefold higher prevalence of MRSA colonisation than what has been reported for point-prevalence screenings among healthcare workers in Germany. Atopic skin diathesis, atopic dermatitis and severe hand eczema are the main risk factors. Thus, prevention and treatment of OSD could be important elements in reduction of colonisation with MRSA among nurses and transmission to others.

Importance of Multifaceted Approaches in Infection Control: A Practical Experience from an Outbreak Investigation

BACKGROUND

This study presents the results of a multidisciplinary, nosocomial MRSA outbreak investigation in an 8-bed medical intensive care unit (ICU). The identification of seven MRSA positive patients in the beginning of 2014 led to the closure of the ward for several weeks. A multidisciplinary, retrospective investigation was initiated in order to identify the reason and the source for the outbreak, describe MRSA transmission in the department and identify limitations in infection control.

METHODS

The investigation comprised an epidemiological description of MRSA cases from 2012 to 2014 and a characterization of MRSA isolates, including phage-, spa- and PFGE-typing. Additionally, MRSA screening was performed from the hospital staff and the environment. To identify the reason for the outbreak, work-related, psychological and behavioral factors were investigated by impartial audits and staff interviews.

RESULTS

Thirty-one MRSA cases were registered during the study period, and 36 isolates were investigated. Molecular typing determined the outbreak strain (phage type 54/812, PFGE type A4, spa type t003) and identified the probable index case. Nasal carriage in one employee and a high environmental contamination with the outbreak strain was documented. Important gaps in nursing procedures and general management were identified. Elevated stress levels and communication problems preceded the outbreak. Compliance with hand hygiene and isolation procedures was evaluated as appropriate.

CONCLUSION

This study demonstrates the complexity of controlling hospital-associated infections. The combined use of different typing methods is beneficial for outbreak investigations. Psychological, behavioral and other work-related factors have an important impact on the spread of nosocomial pathogens. These factors should be addressed and integrated in routine infection control practice.

Antibiotic Resistance of Commensal Staphylococcus aureus and Coagulase-Negative Staphylococci in an International Cohort of Surgeons: A Prospective Point-Prevalence Study

Nasal colonization with antibiotic resistant bacteria represents both a risk factor for the colonized individual and their immediate contacts. Despite the fact that healthcare workers such as orthopedic surgeons are at a critical interface between the healthcare environment and an at-risk patient population, the prevalence of antibiotic resistant bacteria within the surgical profession remains unclear. This study offers a snapshot of the rate of nasal colonization of orthopedic surgeons with multi-resistant staphylococci including methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS). We performed a prospective, observational study obtained at a single time point in late 2013. The participants were active orthopedic, spine and head & neck surgeons from 75 countries. The prevalence of nasal carriage of the different bacteria and the corresponding 95% confidence interval were calculated. From a cohort of 1,166 surgeons, we found an average S. aureus nasal colonization rate of 28.0% (CI 25.4;30.6) and MRSA rate of 2.0% (CI 1.3;2.9), although significant regional variations were observed. The highest rates of MRSA colonization were found in Asia (6.1%), Africa (5.1%) and Central America (4.8%). There was no MRSA carriage detected within our population of 79 surgeons working in North America, and a low (0.6%) MRSA rate in 657 surgeons working in Europe. High rates of MRCoNS nasal carriage were also observed (21.4% overall), with a similar geographic distribution. Recent use of systemic antibiotics was associated with higher rates of carriage of resistant staphylococci. In conclusion, orthopedic surgeons are colonized by S. aureus and MRSA at broadly equivalent rates to the general population. Crucially, geographic differences were observed, which may be partially accounted for by varying antimicrobial stewardship practices between the regions. The elevated rates of resistance within the coagulase-negative staphylococci are of concern, due to the increasing awareness of their importance in hospital acquired and device-associated infection.

The Stealthy Superbug: the Role of Asymptomatic Enteric Carriage in Maintaining a Long-Term Hospital Outbreak of ST228 Methicillin-Resistant Staphylococcus aureus

Whole-genome sequencing (WGS) of 228 isolates was used to elucidate the origin and dynamics of a long-term outbreak of methicillin-resistant Staphylococcus aureus (MRSA) sequence type 228 (ST228) SCCmec I that involved 1,600 patients in a tertiary care hospital between 2008 and 2012. Combining of the sequence data with detailed metadata on patient admission and movement confirmed that the outbreak was due to the transmission of a single clonal variant of ST228, rather than repeated introductions of this clone into the hospital. We note that this clone is significantly more frequently recovered from groin and rectal swabs than other clones (P < 0.0001) and is also significantly more transmissible between roommates (P < 0.01). Unrecognized MRSA carriers, together with movements of patients within the hospital, also seem to have played a major role. These atypical colonization and transmission dynamics can help explain how the outbreak was maintained over the long term. This "stealthy" asymptomatic colonization of the gut, combined with heightened transmissibility (potentially reflecting a role for environmental reservoirs), means the dynamics of this outbreak share some properties with enteric pathogens such as vancomycin-resistant enterococci or Clostridium difficile.

IMPORTANCE

Using whole-genome sequencing, we showed that a large and prolonged outbreak of methicillin-resistant Staphylococcus aureus was due to the clonal spread of a specific strain with genetic elements adapted to the hospital environment. Unrecognized MRSA carriers, the movement of patients within the hospital, and the low detection with clinical specimens were also factors that played a role in this occurrence. The atypical colonization of the gut means the dynamics of this outbreak may share some properties with enteric pathogens.

Nasal carriage of methicillin resistant Staphylococcus aureus among health care workers at a tertiary care hospital in Western Nepal

BACKGROUND

Staphylococcus aureus is a frequent cause of infections in both the community and hospital. Methicillin-resistant Staphylococcus aureus continues to be an important nosocomial pathogen and infections are often difficult to manage due to its resistance to multiple antibiotics. Healthcare workers are important source of nosocomial transmission of MRSA. This study aimed to determine the nasal carriage rate of S. aureus and MRSA among healthcare workers at Universal College of Medical Sciences and Teaching Hospital, Nepal and to determine antibiotic susceptibility pattern of the isolates.

METHODS

A cross-sectional study involving 204 healthcare workers was conducted. Nasal swabs were collected and cultured on Mannitol salt agar. Mannitol fermenting colonies which were gram positive cocci, catalase positive and coagulase positive were identified as S. aureus. Antibiotic susceptibility test was performed by modified Kirby-Bauer disc diffusion method. Methicillin resistance was detected using cefoxitin disc diffusion method.

RESULTS

Of 204 healthcare workers, 32 (15.7 %) were nasal carriers of S. aureus and among them 7 (21.9 %) were carrier of MRSA. Overall nasal carriage rate of MRSA was 3.4 % (7/204). Highest MRSA nasal carriage rate of 7.8 % (4/51) was found among nurses. Healthcare workers of both surgical wards and operating room accounted for 28.6 % (2/7) of MRSA carriers each. Among MRSA isolates inducible clindamycin resistance was observed in 66.7 % (2/3) of erythromycin resistant isolates.

CONCLUSIONS

High nasal carriage of S. aureus and MRSA among healthcare workers (especially in surgery ward and operating room) necessitates improved infection control measures to be employed to control MRSA transmission in our setting.

Comprehensive review of methicillin-resistant Staphylococcus aureus: screening and preventive recommendations for plastic surgeons and other surgical health care providers

BACKGROUND

Up to 2.3 million people are colonized with methicillin-resistant Staphylococcus aureus in the United States, causing well-documented morbidity and mortality. Although the association of clinical outcomes with community and hospital carriage rates is increasingly defined, less is reported about asymptomatic colonization prevalence among physicians, and specifically plastic surgeons and the subsequent association with the incidence of patient surgical-site infection.

METHODS

A review of the literature using the PubMed and Cochrane databases analyzing provider screening, transmission, and prevalence was undertaken. In addition, a search was completed for current screening and decontamination guidelines and outcomes.

RESULTS

The methicillin-resistant S. aureus carriage prevalence of surgical staff is 4.5 percent. No prospective data exist regarding transmission and interventions for plastic surgeons. No studies were found specifically looking at prevalence or treatment of plastic surgeons. Current recommendations by national organizations focus on patient-oriented point-of-care testing and intervention, largely ignoring the role of the health care provider. Excellent guidelines exist regarding screening, transmission prevention, and treatment both in the workplace and in the community. No current such guidelines exist for plastic surgeons.

CONCLUSIONS

No Level I or II evidence was found regarding physician screening, treatment, or transmission. Current expert opinion, however, indicates that plastic surgeons and their staff should be vigilant for methicillin-resistant S. aureus transmission, and once a sentinel cluster of skin and soft-tissue infections is identified, systematic screening and decontamination should be considered. If positive, topical decolonization therapy should be offered. In refractory cases, oral antibiotic therapy may be required, but this should not be used as a first-line strategy.

[Update on outbreaks reported from neonatal intensive care units (2010-203): Staphylococcus aureus]

In terms of the unique risk profile of the patients and the morbidity associated with S. aureus infections in this vulnerable patient population, the literature on outbreaks of S. aureus (including MRSA) in neonatal intensive care units (NICUs) needs to be analyzed separately from reports derived from other intensive care units. With the objective of updating important information for those involved in outbreak management and fostering preventive efforts, this article summarizes the results of a systematic literature analysis, referring to an earlier publication by Gastmeier et al. It focuses on NICU outbreaks caused by S. aureus (including MRSA) and on controlling them.

Nosocomial outbreak of staphyloccocal scalded skin syndrome in neonates in England, December 2012 to March 2013

Staphylococcal scalded skin syndrome (SSSS) is a blistering skin condition caused by exfoliative toxin-producing strains of Staphylococcus aureus. Outbreaks of SSSS in maternity settings are rarely reported. We describe an outbreak of SSSS that occurred among neonates born at a maternity unit in England during December 2012 to March 2013. Detailed epidemiological and microbiological investigations were undertaken. Eight neonates were found to be infected with the outbreak strain of S. aureus, of spa type t346, representing a single pulsotype. All eight isolates contained genes encoding exfoliative toxin A (eta) and six of them contained genes encoding toxin B (etb). Nasal swabs taken during targeted staff screening yielded a staphylococcal carriage rate of 21% (17/80), but none contained the outbreak strain. Mass screening involving multi-site swabbing and pooled, enrichment culture identified a healthcare worker (HCW) with the outbreak strain. This HCW was known to have a chronic skin condition and their initial nasal screen was negative. The outbreak ended when they were excluded from work. This outbreak highlights the need for implementing robust swabbing and culture methodswhen conventional techniques are unsuccessful in identifying staff carrier(s). This study adds to the growing body of evidence on the role of HCWs in nosocomial transmission of S. aureus.

MRSA carriage among healthcare workers in non-outbreak settings in Europe and the United States: a systematic review

Abstarct

Methicillin-resistant Staphylococcus aureus colonization among health care workers in a downtown emergency department in Toronto, Ontario

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) acquired in the community, otherwise known as community-acquired MRSA, has emerged rapidly in recent years. Colonization with MRSA has been associated with an increased risk of symptomatic and serious infections and, in some settings, health care workers (HCWs) exhibit a higher prevalence of MRSA colonization.

OBJECTIVE

To determine MRSA colonization in emergency department (ED) HCWs in the setting of a moderate prevalence of MRSA in skin and soft tissue infections.

METHODS

The present study was conducted at a downtown ED in Toronto, Ontario. ED HCWs completed a brief questionnaire and swabs were taken from one anterior nare, one axilla and any open wounds (if present). Swabs were processed using standard laboratory techniques.

RESULTS

None of the 89 staff (registered nurses [n=55], physicians [n=15], other [n=19]) were MRSA positive and 25 (28.1%) were colonized with methicillin-susceptible S aureus.

CONCLUSIONS

Contrary to common belief among HCWs and previous studies documenting MRSA colonization of HCWs, MRSA colonization of this particular Canadian ED HCW cohort was very low and similar to that of the local population.

Methicillin-resistant Staphylococcus aureus colonization among medical residents

BACKGROUND

Medical residents may be at risk of becoming colonized by methicillin-resistant Staphylococcus aureus (MRSA) during their training. The occupational risk of this specific population is unknown. Furthermore, there are no data regarding MRSA colonization among health care professionals in Quebec.

OBJECTIVE

To determine the MRSA colonization rate in Laval University (Quebec City, Quebec) medical residents and compare it with the MRSA colonization rate of a control group.

METHODS

A controlled cross-sectional study of MRSA prevalence among medical residents of Laval University was performed. The control group consisted of Laval University undergraduate medical students without previous clinical rotations in their curriculum. After informed consent was obtained, participants were screened for MRSA with a nasal swab in both anterior nares. They also completed a questionnaire regarding relevant risk factors and demographic data.

RESULTS

A total of 250 residents of all residency levels from medical and surgical specialties and 247 controls were recruited between February and April 2010. One case of MRSA colonization was detected among the residents and none in the control group (prevalence of 0.4% versus 0.0%; P=1.00).

DISCUSSION

MRSA nasal carriage was very low among Laval University residents. This may reflect the decreasing rate of health care-associated MRSA in Quebec City. Young age and good health may also explain this low risk. The strict infection control policies for MRSA patients (including cohorting, use of gloves, gown and patient-dedicated equipment) may also contribute to prevent MRSA transmission.

CONCLUSIONS

Medical residents in Quebec City appeared to be at very low risk of contracting MRSA through professional activities.

Prevalence of Methicillin Resistant Staphylococcus aureus Carriage amongst Health Care Workers of Critical Care Units in Kasturba Medical College Hospital, Mangalore, India

BACKGROUND

Outbreaks and prevalence of Methicillin resistant Staphylococcus aureus (MRSA) Nosocomial Infection (NI) among various populations have been well reported in literature, particularly those from developed countries. There is a paucity of information on carriage of MRSA in developing nations, including the carriage by critical healthcare givers who are potential transmitters.

AIM AND OBJECTIVES

Present study was aimed at establishing the carriage rate of MRSA among healthcare workers in the critical care units of Kasturba Medical College Hospital, Mangalore, India and at formulating an MRSA control policy, based on the outcomes.

MATERIAL AND METHODS

We screened 200 healthcare workers in the critical care units of the Kasturba Medical College Hospital, Mangalore, India, for MRSA and vancomycin susceptibility of the isolates. Swabs taken from both anterior nares were transported, inoculated onto mannitol salt agar (MSA) and incubated aerobically at 37°C for 18-24 hours. Gram positive cocci in clusters, with positive catalase, coagulase and DNAse tests, were identified as S.aureus. Further categorization of S.aureus into MRSA was done by using cefoxitin disc diffusion method. Sensitivity to vancomycin was tested by vancomycin disc diffusion and vancomycin agar screen plating.

RESULTS

The number of strains of S. aureus which was isolated from our 200 participants was 35, with a rate of 17.5% of the 35 isolates of S. aureus, 5 (14.3%) were MRSA. None of the S. aureus strains were vancomycin resistant.

CONCLUSION

MRSA carriage among healthcare workers who were involved in the management of critically ill patients at Kasturba Medical College hospital, Mangalore, India was 2.5%, which is comfortably low. The existing infection control policy in our hospital seems to be effective and the same should be maintained.

Involvement of occupational physicians in the management of MRSA-colonised healthcare workers in Germany - a survey

Background

Colonisation of healthcare workers (HCWs) with methicillin-resistant Staphylococcus aureus strains (MRSA) is a challenge for any healthcare facility. Persistent carriage of MRSA among HCWs causes special problems, particularly in occupational-medical care. German occupational physicians responsible for healthcare facilities were therefore asked about their experience in managing MRSA-colonised HCWs.

Methods

In May 2012, 549 occupational physicians were asked in writing about in-house management of MRSA-colonised HCWs. The semi-standardised survey form contained questions about collaboration between the infection control team and the occupational physician, the involvement of the occupational physician in in-house management of MRSA carriers and the number of persistently colonised HCWs in 2011. The answers were intended to apply to the largest facility cared for by the occupational physician.

Results

207 occupational physicians took part in the survey (response rate 38%). In 2011, 73 (35%) occupational physicians were responsible for the occupational-medical management of an average of four MRSA-colonised HCWs. Eleven doctors (5.3% of 207) managed a total of 17 persistently colonised HCWs. One of these 17 employees was dismissed. In the case of MRSA carriage among HCWs, most occupational physicians cooperated with the infection control team (77%) and 39% of occupational physicians were responsible for the occupational-medical management of the affected carrier. 65% of facilities had specified policies for the management of MRSA-colonised HCWs. After the first MRSA-positive screening result, 79% of facilities attempt to decolonise the affected employee. In 6% of facilities, the colonised HCWs were excluded from work while receiving decolonisation treatment. In 54% of facilities, infection control policies demand the removal of MRSA carriers from patient care.

Conclusions

Not all facilities have policies for the management of MRSA-colonised HCWs and there are major differences in occupational consequences for the affected HCWs. In order to protect both the employees and the patients, standards for the in-house management of MRSA colonisation in HCWs should be developed.

A social network of hospital acquired infection built from electronic medical record data

OBJECTIVE

Social networks have been used in the study of outbreaks of infectious diseases, including in small group settings such as individual hospitals. Collecting the data needed to create such networks, however, can be time consuming, costly, and error prone. We sought to create a social network of hospital inpatients using electronic medical record (EMR) data already collected for other purposes, for use in simulating outbreaks of nosocomial infections.

MATERIALS AND METHODS

We used the EMR data warehouse of a tertiary academic hospital to model contact among inpatients. Patient-to-patient contact due to shared rooms was inferred from admission-discharge-transfer data, and contact with healthcare workers was inferred from clinical documents. Contacts were used to generate a social network, which was then used to conduct probabilistic simulations of nosocomial outbreaks of methicillin-resistant Staphylococcus aureus and influenza.

RESULTS

Simulations of infection transmission across the network reflected the staffing and patient flow practices of the hospital. Simulations modeling patient isolation, increased hand hygiene, and staff vaccination showed a decrease in the spread of infection.

DISCUSSION

We developed a method of generating a social network of hospital inpatients from EMR data. This method allows the derivation of networks that reflect the local hospital environment, obviate the need for simulated or manually collected data, and can be updated in near real time.

CONCLUSIONS

Inpatient social networks represent a novel secondary use of EMR data, and can be used to simulate nosocomial infections. Future work should focus on prospective validation of the simulations, and adapting such networks to other tasks.

Nosocomial transmission of community-acquired methicillin-resistant Staphylococcus aureus in a well-infant nursery of a teaching hospital

BACKGROUND

Infection due to community-acquired strains of methicillin-resistant Staphylococcus aureus (CA-MRSA) has been reported with increasing frequency. Herein is described the nosocomial transmission of CA-MRSA involving 13 neonates and two mothers in a well-infant nursery in a teaching hospital in Saudi Arabia.

METHODS

From October to November 2009, temporally related cases of CA-MRSA skin and soft-tissue infection occurred in newborns shortly after discharge from a well-infant nursery. An outbreak investigation including case identification, review of medical records, staff screening, environmental cultures, pulsed-field gel electrophoresis, and a case-control study were conducted. Controls were selected from among asymptomatic neonates admitted to the same nursery and matched for the day of admission.

RESULTS

Fifteen subjects were found to be CA-MRSA positive: 13 neonates and two mothers. The crude attack rate among neonates was 5.5% during the outbreak period. All 13 neonates presented with skin and soft-tissue infection; one of the mothers had mastitis and a breast abscess. The source of the outbreak was not evident. Pulsed-field gel electrophoresis showed that all of the tested isolates from one strain except one, all contained the staphylococcal cassette chromosome mec (SCCmec) type IV.

CONCLUSION

MRSA strains that initially emerged in the community are now causing disease in health-care settings. Adherence to standard infection control practices, including consistent hand hygiene, in newborn nurseries is important to prevent transmission in such settings.

Epidemic spread of ST1-MRSA-IVa in a neonatal intensive care unit, Italy

BACKGROUND

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has recently emerged as an important pathogen in neonatal intensive care units (NICUs). The purposes of this study were to characterize methicillin-resistant isolates from an outbreak in a NICU, to examine the genetic traits and clonality of CA-MRSA, and to review the characteristics and outcomes of the neonatal cases and investigate the routes of entry and transmission of the MRSA outbreak strain in the NICU under study.

METHODS

The study NICU practiced an active surveillance program for multidrug-resistant organisms, including weekly cultures for detection of MRSA from nasal swabs among all the admitted neonates. All first isolates from surveillance cultures and all clinical isolates were submitted for susceptibility testing and genotyping. Data from each infant's medical records were prospectively included in a database, and the clinical features and outcomes of the colonized/infected infants were assessed.

RESULTS

A total of 14 infants were colonized or infected by a strain of ST1-MRSA-IVa between April and August 2011. The CA-MRSA strain appeared to have been introduced to the NICU by an infected infant transferred from another hospital. The outbreak was successfully contained by multifaceted infection control interventions.

CONCLUSIONS

The results of this study confirm that NICU is a healthcare setting with a critical permeability to CA-MRSA. Active surveillance including molecular typing can help to detect and monitor the spread of antimicrobial drug-resistant organisms, and thus trigger timely control interventions.

Prevalence of nasal methicillin-resistant Staphylococcus aureus colonization in healthcare workers in a Western Australian acute care hospital

Due to a longstanding comprehensive "search and destroy policy", methicillin-resistant Staphylococcus aureus (MRSA) is not endemic in Western Australian (WA) acute care hospitals. As the prevalence of MRSA in the community has increased, healthcare workers (HCW) are at risk of importing MRSA into hospitals. We aimed to determine the prevalence of and risk factors for nasal MRSA colonization in our HCW population. A period prevalence study was conducted at an 850-bed tertiary hospital. Basic demographics and a nasal swab were obtained. A total of 1,542 HCWs employed in our centre were screened for MRSA, of whom 3.4% (n = 52) were colonized. MRSA colonization was more common in patient care assistants (6.8%) and nurses (5.2%) than in allied health professionals (1.7%) and doctors (0.7%) (p < 0.01). Working in "high-risk" wards that cared for MRSA colonized/infected patients was the strongest risk factor for HCW MRSA colonization (p < 0.001). ST1-IV and ST78-IV (the most common community clones in the region) were the most frequently identified clones. In conclusion, MRSA colonization of HCWs occurs primarily in HCWs caring for patients colonized or infected with MRSA. Surveillance screening of HCWs should be regularly performed on wards with patients with high MRSA colonization prevalence to prevent further spread in the hospital.

Should healthcare workers be screened routinely for meticillin-resistant Staphylococcus aureus? A review of the evidence

Meticillin-resistant Staphylococcus aureus (MRSA) is considered endemic in the UK National Health Service (NHS), and routine MRSA screening of hospital inpatients has recently been introduced in both Scotland and England. The UK National Screening Committee states that public pressure for widening the eligibility criteria of a proposed screening programme should be anticipated and any related decisions scientifically justifiable. A literature review was conducted to examine whether MRSA screening in Scotland should be expanded to include the routine screening of healthcare workers (HCWs). There are no published prevalence studies reporting the overall MRSA carriage rate in HCWs in NHS hospitals. Estimates of HCW carriage from the worldwide literature vary widely depending on the country, hospital specialty and setting (endemic, non-endemic or outbreak). Recent studies conducted in endemic hospital settings report non-outbreak carriage rates of 0-15%. The role of HCW carriage in the transmission of MRSA is not well understood. Persistent carriage could act as a reservoir for infection and HCWs have been implicated as the source in a number of published outbreak reports. There are no published controlled trials examining the impact of routine HCW screening as an intervention in the prevention and control of MRSA infections in the endemic hospital setting. Most of the evidence for HCW screening comes from outbreak reports where the outbreak was brought to an end following the introduction of staff screening as part of a suite of infection control measures. Further research is required before a recommendation could be made to introduce routine MRSA screening of HCWs in the NHS in Scotland.

Prevalence of Staphylococcus aureus colonization in orthopaedic surgeons and their patients: a prospective cohort controlled study

BACKGROUND

Methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus surgical site infections are an increasing health problem in the United States. To date, no study, as far as we know, has evaluated the prevalence of Staphylococcus aureus colonization in orthopaedic surgeons. The purpose of our study was to assess the prevalence of methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus colonization in orthopaedic surgery attending surgeons and residents at our institution compared with that in our high-risk patients.

METHODS

We performed nasal swab cultures in seventy-four orthopaedic attending surgeons and sixty-one orthopaedic surgery residents at our institution, screening for methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus. We compared these results with a prospective database of nasal cultures of patients undergoing joint replacement and spine surgery.

RESULTS

A total of 135 physicians were screened. Of those physicians, 1.5% were positive for methicillin-resistant Staphylococcus aureus and 35.7% were positive for methicillin-sensitive Staphylococcus aureus. None of the sixty-one residents were positive for methicillin-resistant Staphylococcus aureus. However, 59% were positive for methicillin-sensitive Staphylococcus aureus. Of the seventy-four attending surgeons, 2.7% were positive for methicillin-resistant Staphylococcus aureus and 23.3%, for methicillin-sensitive Staphylococcus aureus. Previous studies at our institution have demonstrated a 2.17% prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus and an 18% rate of methicillin-sensitive Staphylococcus aureus in high-risk patients. Thus, no difference was found between the prevalence of methicillin-resistant Staphylococcus aureus in residents or attending surgeons and that in the high-risk patients. However, the prevalence of methicillin-sensitive Staphylococcus aureus colonization in the surgeons (35.7%) was significantly higher than that in the high-risk patient group (18%) (p < 0.01).

CONCLUSIONS

At a major teaching hospital, a higher prevalence of methicillin-sensitive Staphylococcus aureus colonization was found among attending and resident orthopaedic surgeons compared with a high-risk patient group, but the prevalence of methicillin-resistant Staphylococcus aureus colonization was similar.

[Methicillin-resistant Staphylococcus aureus (MRSA) infections. Epidemiology, diagnostics, therapy, and prevention]

The increasing number of complicated soft-tissue or invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA) is a frequent reason for elaborate treatment regimens. Unidentified MRSA carriers may be the origin of endemic spread to other patients and medical staff. Recently, community-associated cMRSA with particular virulence factors were isolated from persons without the typical history of hospital contacts. Molecular tools for the timely detection of the mecA resistance gene for the identification of MRSA in medical test specimens have become a standard approach in MRSA-related diagnostic procedures. The actual therapy of MRSA infections requires consideration of both the appropriate spectrum of activity and the adequate pharmacological properties of a chosen antimicrobial. Preventive strategies rely on the consistent application of standard hygiene precautions, which have to be supplemented with increased barriers for the isolation of identified MRSA patients.

Implementing the MRSA recommendations made by the Commission for Hospital Hygiene and Infection Prevention (KRINKO) of 1999 - current considerations by the DGKH Management Board

In Germany, recommendations on dealing with patients who are colonised with methicillin-resistant S. aureus (MRSA) for the inpatient sector have been published in 1999 by the Commission for Hospital Hygiene and Infection Prevention (KRINKO). Some challenges arise with regard to the practical implementation of the KRINKO recommendations. These challenges do not principally question the benefit of the recommendations but have come into criticism from users. In this commentary the German Society for Hospital Hygiene (DGKH) discusses some controversial issues and adds suggestions for unresolved problems regarding the infection control management of MRSA in healthcare settings.

A prevalence screen of MRSA nasal colonisation amongst UK doctors in a non-clinical environment

Screening for methicillin-resistant Staphylococcus aureus (MRSA) carriage in healthcare workers (HCWs) is both contentious and confounded by a lack of knowledge of background prevalence rates. This study examines prevalence of nasal MRSA carriage amongst a spectrum of medical professionals in a non-clinical environment. Medical conference attendees volunteered for screening for nasal MRSA carriage, and anonymised demographic data and attitudes towards screening were recorded. Two hundred sixty volunteers participated. One hundred seventy-three participants (67%) were from the British Medical Association's Annual Representatives Meeting, and 87 participants (33%) were attending the Association of Surgeons in Training conference. Six (2%) participants were positive for MRSA nasal carriage (BMA = 1%, ASIT = 5%; p = 0.099). Participants from a surgical specialty (4.8%) were more likely to be MRSA positive (p = 0.039). All positive samples came from male participants (p = 0.182). However, there was no significant association with gender, seniority or country of employment and MRSA status. Routine screening for MRSA was supported by 63% of participants in HCWs; 36% had previously undergone such screening. MRSA nasal carriage rates within this cross-sectional study are lower than studies reporting carriage rates in HCWs within the clinical environment. Further research is required to examine the relationship between MRSA nasal colonisation status of a HCW and subsequent MRSA infection in patients.