Diagnostic accuracy of rapid antigen tests in cerebrospinal fluid for pneumococcal meningitis: a systematic review and meta-analysis

BackgroundStreptococcus pneumoniae is a leading cause of bacterial meningitis worldwide. Conventional microbiological assays take several days and require the use of various drugs for empirical treatment. Rapid antigen tests in cerebrospinal fluid (CSF) may be useful to triage pneumococcal meningitis immediately.ObjectivesTo elucidate whether rapid antigen tests in CSF are useful in the triage of pneumococcal meningitis.MethodsData sourcesCochrane CENTRAL, MEDLINE, EMBASE, World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov databases were searched.Study eligibility criteriaAll types of cohort studies except multiple-group studies, where the sensitivity and specificity of rapid antigen tests in CSF compared with CSF culture can be extracted.ParticipantsPatients with suspected meningitis.TestsRapid antigen tests in CSF.Reference standardsOne or more of the following: blood culture, CSF culture, and polymerase chain reaction in CSF.Assessment of risk of biasThe methodological quality of the included studies was assessed using QUADAS-2.Methods of data synthesisWe used a random-effects bivariate model for the meta-analysis. We conducted a subgroup analysis by dividing studies into types of antigen tests, adults and children, low-income and high-income countries, and with or without exposure to antibiotics before lumbar puncture.ResultsForty-four studies involving 14 791 participants were included. Most studies had a moderate-to-low methodological quality. Summary sensitivity and specificity were 99.5% (95% confidence interval (CI), 92.4–100%) and 98.2% (95% CI, 96.9–98.9%), respectively. Positive predictive values and negative predictive values at the median prevalence (4.2%) in the included studies were 70.8% (95% CI, 56.6–79.9%) and 100% (95% CI, 99.7–100%), respectively. The diagnostic accuracy was consistent across the various subgroups, except for slightly reduced sensitivity in high-income countries.ConclusionsRapid antigen tests in CSF would be useful in triaging pneumococcal meningitis. Further studies are warranted to investigate the clinical benefit of ruling out pneumococcal meningitis based on the results of rapid antigen tests.     

Diagnostic accuracy of tests for leprosy: a systematic review and meta-analysis

ObjectivesOwing to difficulties in the clinical diagnosis of leprosy, several complementary tests have been developed and used. The aim was to systematically summarize the accuracy of diagnostic tests for leprosy.MethodsWe searched for relevant articles in Embase, Medline, and Global Health databases, until June 2017. Studies evaluating the accuracy of any diagnostic techniques for differentiating between people with and without leprosy were included. Studies solely focusing on differentiating between the separate forms of leprosy were excluded. Our protocol was registered on PROSPERO (CRD42017071803). We assessed study quality using the QUADAS-2 checklist. A bivariate random effects regression model was used for the meta-analyses.ResultsWe included 78 studies, most of those evaluating the detection of IgM antibodies against phenolic glycolipid I using ELISA. Sensitivity of the 39 studies evaluating ELISA was 63.8% (95% CI 55.0–71.8); specificity 91.0% (95% CI 86.9–93.9). The lateral flow test (nine studies) and the agglutination test (five studies) had a slightly higher sensitivity and a slightly lower specificity. Sensitivity of qPCR was (five studies) 78.5% (95% CI 61.9–89.2) and specificity 89.3% (95% CI 61.4–97.8). Sensitivity of conventional PCR was (17 studies) 75.3% (95% CI 67.9–81.5) and specificity 94.5% (95% CI 91.4–96.5).ConclusionsAlthough the test accuracy looks reasonable, the studies suffered from heterogeneity and low methodological quality.     

Screening for methicillin-resistant Staphylococcus aureus in clinical swabs using a high-throughput real-time PCR-based method.

The presence of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals and the community is a serious problem. Accordingly, a comprehensive plan has been implemented in the County of Vejle, Denmark, to identify colonised and/or infected individuals and to control the spread of MRSA. Since 2005, all patients and healthcare personnel have been screened for MRSA colonisation, involving analysis of 300-400 samples daily. To deal with this number of samples, a PCR-based method customised for high-throughput analysis and a system for fast reporting of MRSA carrier status were developed. Swab samples were incubated overnight in a selective tryptone soya broth and were analysed by PCR the following day. Using this strategy, non-colonised individuals were identified within 24 h, while MRSA-positive samples were analysed further by traditional microbiological methods to determine the resistance pattern. This is a cost-effective approach, as the greatest expense in hospitals involves the isolation of patients of unknown MRSA status. The method was evaluated by testing 2194 clinical samples, with a sensitivity and specificity of 100% and 94%, respectively. The analytical sensitivity was 97%, with 161 of 166 different MRSA strains and isolates generating positive results according to PCR analysis. Using four control strains, the inter-assay variation was revealed to be a maximum of 2.6%, indicating good reproducibility.     

Direct detection of methicillin-resistant Staphylococcus aureus in clinical specimens by a nucleic acid-based hybridisation assay

The occurrence of methicillin-resistant Staphylococcus aureus (MRSA) is still increasing worldwide and is associated with significant morbidity, mortality and hospital costs. Screening for MRSA plays a key role in limiting further nosocomial spread of this organism. Control measures require a rapid and sensitive test for direct detection of MRSA carriage. This study evaluated an easy-to-use PCR-hybridisation assay for the direct detection of MRSA in clinical swab specimens. In total, 508 pairs of swabs from 242 patients at risk for MRSA carriage were analysed by the standard culture method and the PCR assay. One swab was used for PCR and culture, while the second was used for culture only. Of the 508 pairs tested, 37 were positive by culture and 35 were positive by PCR. Among the 471 culture-negative specimens, 465 were negative by PCR and six were PCR-positive. The PCR assay had a sensitivity of 94.59%, a specificity of 98.73%, a positive predictive value of 85.37%, and a negative predictive value of 99.57%. The PCR-hybridisation assay enabled reliable detection of MRSA carriage in c. 4 h, thereby allowing its effective use in an MRSA control strategy.     

Evaluation of laboratory tests for detection of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

Few studies evaluating susceptibility testing of methicillin-resistant staphylococci have included isolates of Staphylococcus epidermidis, a known pathogen in many types of serious infections. We tested 175 S. epidermidis and 95 Staphylococcus aureus isolates to determine the most sensitive procedures for detecting methicillin-resistant staphylococci. Reference procedures included agar dilution with methicillin and 4% NaCl in the agar and broth microdilution with methicillin and 2% NaCl in cation-supplemented Mueller-Hinton broth. After 24 h of incubation, the results from both methods correlated well and were within 1 log2 dilution for all isolates tested. Only one-half of all resistant isolates (92 of 183) were detected at 18 h by using the standard disk diffusion technique with 5-micrograms methicillin disks, and even fewer were detected with 10-micrograms methicillin disks and newly recommended zone-size criteria. However, the standard disk diffusion method with 4% NaCl in the agar increased the sensitivity and specificity for identification of the proper phenotype to greater than 92%. The spread plate and new spot techniques, both using agar with 4% NaCl, were also sensitive methods. Of 47 S. epidermidis isolates tested against oxacillin, 6 (13%) were oxacillin susceptible but methicillin resistant. Two automated systems, the Automicrobic system (Vitek Systems) and MicroScan (American MicroScan), as well as two broth screening systems available from Remel and Austin Biological Laboratories, failed to detect several resistant isolates, depending on the species.     

Diagnostic accuracy of adenosine deaminase for tuberculous peritonitis: a meta-analysis

Introduction

Tuberculous peritonitis remains a diagnostic challenge for clinicians. Many studies have investigated the usefulness of adenosine deaminase (ADA) in ascites for the diagnosis of tuberculous peritonitis; however, the overall diagnostic accuracy of ADA for tuberculous peritonitis remains unclear. The aim of the present meta-analysis was to determine the overall accuracy of ADA measurements in the diagnosis of tuberculous peritonitis.

Material and methods

We performed a systematic search in PubMed and Embase to identify published studies that evaluated the diagnostic role of ADA for tuberculous peritonitis. Quality was assessed according to standardized Quality Assessment of Diagnostic Accuracy Studies criteria. Sensitivity, specificity and other measures of accuracy of ADA assay in order to diagnose tuberculous peritonitis were pooled using random effects models. Summary receiver operating characteristic curve (SROC) was used to summarize overall test performance.

Results

Sixteen studies met inclusion criteria for the present meta-analysis. The pooled sensitivity and specificity for diagnosing tuberculous peritonitis were 0.93 (95% CI: 0.89–0.95) and 0.96 (95% CI: 0.94–0.97), respectively. The positive likelihood ratio was 15.80 (95% CI: 10.87–22.95), negative likelihood ratio was 0.09 (95% CI: 0.05–0.16) and diagnostic odds ratio was 249.28 (95% CI: 113.11–549.39). The area under the SROC was 0.98.

Conclusions

Ascitic ADA determination is a relatively sensitive and specific test for the diagnosis of tuberculous peritonitis. Measurement of ADA in ascites is thus likely to be a useful diagnostic method for tuberculous peritonitis.     

Diagnostic value of microRNA for pancreatic cancer: a meta-analysis

Introduction

MicroRNAs have been reported to be aberrantly expressed in patients with pancreatic cancer. The aim of the present meta-analysis is to establish the overall diagnostic accuracy of the measurement of microRNA for diagnosing pancreatic cancer.

Material and methods

After a systematic review of English language studies from Medline, Embase, and Cochrane Library, the sensitivity, specificity, and other measures of accuracy of microRNA in the diagnosis of pancreatic cancer were pooled using random-effects models. The methodological quality of each study was assessed by QUADAS (quality assessment for studies of diagnostic accuracy). Statistical analysis was performed by employing Meta-Disc 1.4 software and STATA. Summary receiver operating characteristic curves were used to summarize overall test performance. Deeks’ test was used to test the potential publication bias.

Results

Nine studies from seven publications met our inclusion criteria. The summary estimates for microRNAs in the diagnosis of pancreatic cancer in these studies were pooled sensitivity 0.89 (95% CI: 0.86-0.91), specificity 0.93 (95% CI: 0.90-0.95), positive likelihood ratio 11.62 (95% CI: 5.75-23.50), negative likelihood ratio 0.14 (95% CI: 0.08-0.24), diagnostic odds ratio 115.13 (95% CI: 33.73-351.28), and the area under the curve was 0.97.

Conclusions

MicroRNA assay plays an important role in the diagnosis of pancreatic cancer. The results of microRNA assays should be interpreted in parallel with clinical findings and the results of conventional tests.     

Diagnostic accuracy of rapid nucleic acid tests for group A streptococcal pharyngitis: systematic review and meta-analysis

BackgroundAcute pharyngitis is one of the most common conditions in outpatient settings and an important source of inappropriate antibiotic prescribing. Rapid antigen detection tests (RADTs) offer diagnosis of group A streptococcus at the point of care but have limited sensitivity. Rapid nucleic acid tests (RNATs) are now available; a systematic review of their accuracy is lacking.ObjectivesTo evaluate the accuracy of RNATs in patients with pharyngitis; to explore test-level and study-level factors that could explain variability in accuracy; and to compare the accuracy of RNATs with that of RADTs.Data sourcesMEDLINE, Embase, Web of Science (1990–2020).Study eligibility criteriaCross-sectional studies and randomized trials.ParticipantsPatients with pharyngitis.Index test/s and reference standardsRNAT commercial kits compared with throat culture.MethodsWe assessed risk of bias and applicability using QUADAS-2. We performed meta-analysis of sensitivity and specificity using the bivariate random-effects model. Variability was explored by subgroup analyses and meta-regression.ResultsWe included 38 studies (46 test evaluations; 17 411 test results). RNATs were most often performed in a laboratory. The overall methodological quality of primary studies was uncertain because of incomplete reporting. RNATs had a summary sensitivity of 97.5% (95% CI 96.2%–98.3%) and a summary specificity of 95.1% (95% CI 93.6%–96.3%). There was low variability in estimates across studies. Variability in sensitivity and specificity was partially explained by test type (p < 0.05 for both). Sensitivity analyses limited to studies with low risk of bias showed robust accuracy estimates. RNATs were more sensitive than RADTs (13 studies; 96.8% versus 82.3%, p 0.004); there was no difference in specificity (p 0.92).ConclusionsThe high diagnostic accuracy of RNATs may allow their use as stand-alone tests to diagnose group A streptococcus pharyngitis. Based on direct comparisons, RNATs have greater sensitivity than RADTs and equal specificity. Further studies should evaluate RNATs in point-of-care settings.     

Rapid screening of methicillin-resistant Staphylococcus aureus using PCR and chromogenic agar: a prospective study to evaluate costs and effects

Pre-emptive isolation of suspected methicillin-resistant Staphylococcus aureus (MRSA) carriers is considered essential for controlling the spread of MRSA, but noncolonized patients will be isolated unnecessarily as a result of a delay in diagnosis of 3–5 days with conventional cultures. We determined costs per isolation day avoided, and incremental costs of rapid MRSA screening tests when added to conventional screening, but with decisions on isolation measures based on PCR results. A prospective multicentre study evaluating BD GeneOhm MRSA PCR (‘IDI’) (BD Diagnostics, San Diego, CA, USA), Xpert MRSA (‘GeneXpert’) (Cepheid, Sunnyvale, CA, USA) and chromogenic agar (MRSA-ID) (bioMérieux, Marcy-l’Etoile, France) was performed in 14 Dutch hospitals. Among 1764 patients at risk, MRSA prevalence was 3.3% (n = 59). Duration of isolation was 19.7 and 16.1 h with IDI and GeneXpert, respectively, and would have been 30.0 and 76.2 h when based on chromogenic agar and conventional cultures, respectively. Negative predictive values (at a patient level) were 99.5%, 99.1% and 99.5% for IDI, GeneXpert and chromogenic agar, respectively. Numbers of isolation days were reduced by 60% and 47% with PCR-based and chromogenic agar-based screening, respectively. The cost per test was €56.22 for IDI, €69.62 for GeneXpert and €2.08 for chromogenic agar, and additional costs per extra isolation day were €26.34. Costs per isolation day avoided were €95.77 (IDI) and €125.43 (GeneXpert). PCR-based decision-making added €153.64 (IDI) and €193.84 (GeneXpert) per patient to overall costs and chromogenic testing would have saved €30.79 per patient. Rapid diagnostic testing safely reduces the number of unnecessary isolation days, but only chromogenic screening, and not PCR-based screening, can be considered as cost saving.     

Real-time multiplex PCR for direct detection of methicillin-resistant Staphylococcus aureus (MRSA) in clinical samples enriched by broth culture

A real-time multiplex PCR using the orfX and staphylococcal cassette chromosome (SCC) mec of Staphylococcus aureus was developed. The aim was to achieve a rapid and sensitive high-throughput method for direct detection of heterogeneous methicillin-resistant S. aureus (MRSA) in clinical samples, present in a low-endemic population, such as in Sweden. Consecutive broth enriched pooled clinical screening samples (nares, throat and/or perineum/groin) (n = 541 pools), broth enriched clinical samples showing growth of methicillin-sensitive S. aureus (MSSA) (n = 95 pools), clinical MRSA isolates (n = 173), MRSA reference strains (n = 43) and various coagulase-negative staphylococcal isolates (n = 33) were analyzed. The multiplex PCR detected all heterogeneous MRSA strains (n = 173) obtained in our area as well as all pooled consecutive broth enriched clinical samples with MRSA, i. e. 36 of 541 pools. None of the CoNS were positive. However, 18 out of 541 pools (3.3%) were positive in the multiplex PCR but no growth of MRSA could be detected by subculture and were regarded as false positive. Furthermore, the assay is rapid and reliable negative results can be delivered to the clinician within 18 h that will facilitate the infection control management of patients and hospital staff.     

Diagnostic accuracy of VIDISCA-NGS in patients with suspected central nervous system infections

ObjectivesConfirming the diagnosis in viral central nervous system (CNS) infections can be difficult with the currently available diagnostic tools. Virus discovery cDNA-amplified fragment length polymorphism next-generation sequencing (VIDISCA-NGS) is a promising viral metagenomic technique that enables the detection of all viruses in a single assay. We performed a retrospective study on the diagnostic accuracy of VIDISCA-NGS in cerebrospinal fluid (CSF) of individuals with suspected CNS infections.MethodsConsecutive adult patients presenting to the Emergency Department or inpatients, who underwent a lumbar puncture for the suspicion of a CNS infection, were included if they were diagnosed with a viral CNS infection, or if a viral CNS infection was initially suspected but eventually a different diagnosis was made. A quantitative PCR panel of the most common causative viruses was performed on CSF of these patients as reference standard and compared with the results of VIDISCA-NGS, the index test.ResultsWe included 38 individuals with viral CNS infections and 35 presenting with suspected CNS infection for whom an alternative aetiology was finally established. Overall sensitivity and specificity were 52% (95% CI 31%–73%) and 100% (95% CI 91%–100%), respectively. One enterovirus, detected by VIDISCA-NGS, was only identified by quantitative PCR upon retesting. Additional viruses identified by VIDISCA-NGS consisted of GB virus C, human papillomavirus, human mastadenovirus C, Merkel cell polyoma virus and anelloviruses.ConclusionIn patients for whom routine diagnostics do not yield a causative pathogen, VIDISCA-NGS can be of additional value as it can detect a broader range of viruses, but it does not perform well enough to replace quantitativePCR.     

Diagnostic accuracy of fecal lactoferrin for inflammatory bowel disease: a meta-analysis

Objective: To do a systematic review using meta-analysis to assess the diagnostic accuracy of fecal lactoferrin (FL) in patients with inflammatory bowel disease (IBD). Methods: We performed a literature review and systematically searched the Medline and EMBASE databases for eligible studies. The quality of the included studies was assessed using the QUADAS tool. The sensitivity, specificity, and other diagnostic indexes of FL were pooled using a random-effects model. Results: Seven studies, involving 1816 patients, met the inclusion criteria. In all studies, the pooled FL sensitivity and pooled specificity were 0.82 (95% confidence interval [CI]: 0.72, 0.89) and 0.95 (95% CI: 0.88, 0.98), respectively. The positive and negative likelihood ratios were 16.63 and 0.18, respectively. The area under the summary receiver-operating characteristic curve (SROC) was 0.95 (95% CI: 0.93, 0.97), and the diagnostic odds ratio was 90.04 (95% CI: 37.01, 219.02). The pooled FL sensitivity and specificity for Crohn’s disease (CD) diagnosis (sensitivity =75%, specificity =100%) was not as good as it was for ulcerative colitis (UC) diagnosis (sensitivity =82%, specificity =100%). Conclusion: FL, as a noninvasive and screening marker, has a high specificity and a modest specificity during the diagnosis of suspected IBD.     

Clinical and molecular epidemiology of community-acquired, healthcare-associated and nosocomial methicillin-resistant Staphylococus aureus in Spain

A prospective cohort study including all new cases of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection in 64 Spanish hospitals during June 2003 was performed to investigate the epidemiology of MRSA in Spain. Only patients who yielded clinical MRSA-positive samples were included. Epidemiological and clinical data for a total of 370 cases were collected. Genotyping was performed using pulsed-field gel electrophoresis and multilocus sequence typing. Panton–Valentine leukocidin genes and the staphylococcal chromosomal cassette mec (SCC mec ) were identified in representative isolates. MRSA was considered to be nosocomially acquired in 202 cases (55%), healthcare-associated (HCA) in 139 cases (38%), community-acquired (CA) in three cases, and of uncertain mode of acquisition in 26 (7%) cases. The pooled population-based rate was 2.31 cases/100 000 population/month, and the pooled nosocomial rate was 0.21 cases/1000 hospital stays (20.2% of S. aureus ). Peripheral vascular disease, respiratory tract infections, catheter infections, bloodstream infections and crude mortality were more frequent among HCA cases, whereas neoplasia and urinary tract infections were more frequent among nosocomially acquired cases. Two clones related to the paediatric clone ST5-IV accounted for 71% of the isolates; EMRSA-16 has emerged in two different geographical areas. Only one isolate belonged to the formerly predominant Iberian clone. The three CA isolates were related to the USA300 clone. SCC mec type IV was the most frequent type in nosocomial and HCA isolates. The epidemiology of MRSA has changed in Spain; outpatients with previous healthcare contact represent a very important reservoir of MRSA, and community isolates are emerging.     

Diagnostic accuracy of loop-mediated isothermal amplification in detection of Clostridium difficile in stool samples: a meta-analysis

Introduction

Clostridium difficile infection (CDI) remains a diagnostic challenge for clinicians. More recently, loop-mediated isothermal amplification (LAMP) has become readily available for the diagnosis of CDI, and many studies have investigated the usefulness of LAMP for rapid and accurate diagnosis of CDI. However, the overall diagnostic accuracy of LAMP for CDI remains unclear. In this meta-analysis, our aim was to establish the overall diagnostic accuracy of LAMP in detection of Clostridium difficile (CD) in stool samples.

Material and methods

A search was done in PubMed, MEDLINE, EMBASE and Cochrane Library databases up to February 2014 to identify published studies that evaluated the diagnostic role of LAMP for CD. Methodological quality was assessed according to the quality assessment for studies of diagnostic accuracy (QUADAS) instrument. The sensitivities (SEN), specificities (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnostic odds ratio (DOR) were pooled statistically using random effects models. Statistical analysis was performed by employing Meta-Disc 1.4 software. Summary receiver operating characteristic (SROC) curves were used to summarize overall test performance. Funnel plots were used to test the potential publication bias.

Result

A total of 9 studies met inclusion criteria for the present meta-analysis. The pooled SEN and SPE for diagnosing CD were 0.93 (95% CI: 0.91–0.95) and 0.98 (95% CI: 0.98–0.99), respectively. The PLR was 47.72 (95% CI: 15.10–150.82), NLR was 0.07 (95% CI: 0.04–0.14) and DOR was 745.19 (95% CI: 229.30−2421.72). The area under the ROC was 0.98. Meta-regression indicated that the total number of samples was a source of heterogeneity for LAMP in detection of CD. The funnel plots suggested no publication bias.

Conclusions

The LAMP meets the minimum desirable characteristics of a diagnostic test of SEN, SPE and other measures of accuracy in the diagnosis of CD, and it is suitable as a rapid, effective and reliable stand-alone diagnostic test for diagnosis of CDI, potentially decreasing morbidity and nosocomial spread of CD.     

Laboratory tools and strategies for methicillin-resistant Staphylococcus aureus screening, surveillance and typing: state of the art and unmet needs

The public health burden caused by methicillin-resistant Staphylococcus aureus (MRSA) infections is now widely recognized, and is a cause of public alarm. Effective MRSA risk management in the healthcare system as well as in the community should rely on accurate detection of reservoirs and sources of transmission, as well as on close monitoring of the impact of interventions on disease incidence and bacterial dissemination. MRSA carrier screening and disease surveillance, coupled with molecular typing, are key information tools for integrated MRSA control and individual risk assessment. These tools should be tailored to the distinct needs of local interventions and national prevention programmes. Surveillance schemes should primarily inform local staff and serve as quality assurance about MRSA risk management. New technologies, including the use of selective culture media and real-time PCR assays, allow faster detection of MRSA carriers upon admission or during stay in healthcare institutions. More research is needed to ascertain their cost-effectiveness for MRSA control. Likewise, tremendous progress has been made concerning molecular typing methods, with optimization and standardization of sequence-based technologies offering broad applicability and high throughput. However, no single S. aureus typing method is yet providing fully reliable information within the range of discrimination needed for public health action. Further refinement of genotyping methods and international harmonization of surveillance and typing schemes must be achieved to facilitate global MRSA control.     

Community-associated methicillin-resistant Staphylococcus aureus: risk factors for infection, and long-term follow-up

Uncertainty persists about risk factors for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in Europe and the long-term efficacy of decolonization strategies. To evaluate risk factors for CA-MRSA in Geneva, Switzerland, a hospital-based, retrospective case–control study of 26 patients with CA-MRSA infection and 60 control patients was performed. To evaluate the long-term effect of a systematic decolonization strategy (with and without concomitant systemic antibiotic therapy) for CA-MRSA patients, a prospective cohort study of 79 patients with Panton–Valentine leukocidin-producing CA-MRSA isolates was conducted. Nationality other than European Union or Swiss (adjusted OR 6.09; 95% CI  1.07–34.65) and absence of healthcare contact (adjusted OR 0.11, 95% CI  0.02–0.59) were independent predictors of CA-MRSA infection. Forty-five cases were followed (median, 22 months) to assess the long-term efficacy of the decolonization strategy; 39/45 (86.7%) had no clinical relapse and were MRSA-negative at their last follow-up, whereas six remained MRSA-positive. Five of these six cases belonged to a family cluster. Decolonization rates were similar between infected patients and asymptomatic carriers (92.6% vs. 77.8%, p = 0.20). This study shows a lack of readily modifiable risk factors for CA-MRSA infection in this population, and suggests the potential usefulness of conducting decolonization procedures in a setting with sporadic CA-MRSA infection. Further studies are needed to elucidate the role of migration as a factor contributing to the emergence of CA-MRSA in Europe.     

Use of broth enrichment and real-time PCR to exclude the presence of methicillin-resistant Staphylococcus aureus in clinical samples: a sensitive screening approach

A rapid and sensitive method for excluding the presence of methicillin-resistant Staphylococcus aureus (MRSA) in clinical samples was developed and evaluated. The method utilised an MRSA-selective enrichment broth for 16 h, followed by PCR quantification of the nuc gene. Samples below a quantitative PCR threshold were reported as MRSA-negative. Broths from PCR-positive samples were subcultured for MRSA isolation. Clinical samples (n = 334) in a constructed high prevalence population were analysed in parallel with a selective plating method. The new broth-PCR assay increased the number of positive samples by 35% (49 vs. 66), and 94% of negative samples were reported within 24 h. To reduce costs and workload, 665 clinical samples were grown separately in enrichment broth and then pooled in the PCR step. The broth-PCR assay increased the number of MRSA positive samples from 11 to 15 compared with selective plating. Most (89%) of the culture-negative samples were also PCR-negative and could be reported within 24 h. The growth of 25 European EMRSA strains was tested in the selective enrichment broth. On average, the MRSA strains showed a 300 000-fold increase in CFU, compared with 30-fold for the eight methicillin-sensitive Staphylococcus aureus strains tested.     

Clonal dissemination of epidemic methicillin-resistant Staphylococcus aureus in Belgium and neighboring countries

Objectives   To determine the diversity of pulsed-field gel electrophoresis (PFGE) types among epidemic strains of methicillin-resistant Staphylococcus aureus (MRSA) recovered in Belgium, France, Germany and The Netherlands over the period 1981–94.
Methods   MRSA strains collected in a multicenter survey in Belgium ( n = 171) and from reference laboratories in neighboring countries ( n = 102) were characterized by PFGE analysis using the Sma I enzyme.
Results   In total, 32 PFGE types were found. Epidemic PFGE type 1, first recognized in 1984, accounted for 82% of Belgian strains (87% of hospitals) and 51% of European MRSA strains. Four other internationally epidemic PFGE types (types 8, 10, 11 and 12) were less widely disseminated and more recently detected (1991–94), each recovered from two or three countries. International spread of two PFGE types was linked to transfer of colonized patients to Dutch hospitals from another country where this type was frequently recovered.
Conclusions   Genotypic analysis indicated widespread distribution of several outbreak-associated MRSA strains over large European regions, which was in some instances related to interhospital patient transfer. These findings underscore the need for standardized international surveillance and control of MRSA transmission between healthcare institutions across Europe.     

Lack of evidence for persistent nasal colonization with community-acquired methicillin-resistant Staphylococcus aureus in a central European cohort

One hundred and three patients who had previously tested positive for community-acquired methicillin-resistant Staphylococcus aureus (cMRSA) were followed up for a mean time of 32.6 months. Eighty patients had a history of skin or soft tissue infection, and the remainder were mostly asymptomatic carriers. Of 103 patients, only two reported ongoing symptoms with abscess formation. Of 81 nasal swabs available, 30.9% were positive for S. aureus but only four yielded Panton–Valentine leukocidin-positive methicillin-resistant S. aureus. In summary, we were unable to find persistent health issues or nasal colonization with cMRSA in a cohort of previously cMRSA-infected/colonized patients.