Targeted mupirocin-based decolonization for Staphylococcus aureus carriers and the subsequent risk of mupirocin resistance in haemodialysis patients - a longitudinal study over 20 years.

Mupirocin-based decolonization of Staphylococcus aureus carriers undergoing haemodialysis is not widely implemented due to concerns of mupirocin resistance. In our haemodialysis unit, a strategy combining universal S. aureus screening with targeted mupirocin-based decolonization was introduced two decades ago. In this study of haemodialysis patients, mupirocin resistance was assessed in blood and colonizing S. aureus isolates during two periods. Mupirocin resistance in S. aureus was infrequent in both blood and colonizing isolates. Furthermore, in the years 2003-2021, a decreasing trend in the annual rate of S. aureus bloodstream infections was observed. Targeted mupirocin-based decolonization of S. aureus carriers undergoing haemodialysis is a sustainable measure for preventing healthcare-associated infections.

Outbreak of Pseudomonas aeruginosa producing VIM carbapenemase in an intensive care unit and its termination by implementation of waterless patient care.

BACKGROUND: Long-term outbreaks of multidrug-resistant Gram-negative bacilli related to hospital-building water systems have been described. However, successful mitigation strategies have rarely been reported. In particular, environmental disinfection or replacement of contaminated equipment usually failed to eradicate environmental sources of Pseudomonas aeruginosa. METHODS: We report the investigation and termination of an outbreak of P. aeruginosa producing VIM carbapenemase (PA-VIM) in the adult intensive care unit (ICU) of a Swiss tertiary care hospital with active case finding, environmental sampling and whole genome sequencing (WGS) of patient and environmental strains. We also describe the implemented control strategies and their effectiveness on eradication of the environmental reservoir. RESULTS: Between April 2018 and September 2020, 21 patients became either infected or colonized with a PA-VIM strain. For 16 of them, an acquisition in the ICU was suspected. Among 131 environmental samples collected in the ICU, 13 grew PA-VIM in sink traps and drains. WGS confirmed the epidemiological link between clinical and environmental strains and the monoclonal pattern of the outbreak. After removing sinks from patient rooms and implementation of waterless patient care, no new acquisition was detected in the ICU within 8 months after the intervention. DISCUSSION: Implementation of waterless patient care with removal of the sinks in patient rooms was successful for termination of a PA-VIM ICU outbreak linked to multiple environmental water sources. WGS provides highly discriminatory accuracy to investigate environment-related outbreaks.

Comparison of the Copan WASPLab incorporating the BioRad expert system against the SIRscan 2000 automatic for routine antimicrobial disc diffusion susceptibility testing.

OBJECTIVES: This study investigated the agreement at the categorical level between the Copan WASPLab incorporating the BioRad expert system against the SIRscan 2000 automatic for antimicrobial disc diffusion susceptibility testing. METHODS: The 338 clinical strains (67 Pseudomonas aeruginosa, 19 methicillin-resistant Staphylococcus aureus, 75 methicillin-sensitive S. aureus and 177 Enterobacterales isolates) analysed in this study were non-duplicate isolates obtained from consecutive clinical samples referred to the clinical bacteriology laboratory at Geneva University Hospitals between June and August 2019. For the WASPLab the inoculum suspension was prepared in strict accordance with the manufacturer's instruction (Copan WASP srl, Brescia, Italy) by adding 2 mL of the 0.5 McFarland primary suspension used for the SIRscan analysis into a sterile tube filled with 4 mL of sterile saline (1:3 dilution). The inoculum (2 × 30 µL loop/spreader) was spread over the entire surface of Mueller-Hinton agar plates according to the AST streaking pattern defined by Copan. The antibiotic discs were dispensed by the WASP and inoculated media were loaded on conveyors for transfer to the automatic incubators. The plates were incubated for 16 h, and several digital images were acquired. Inhibition zone diameters were automatically read by the WASPLab and were adjusted manually whenever necessary. For the SIRscan 2000 automatic, the antimicrobial disc diffusion susceptibility testing was performed according to the EUCAST guidelines. The gradient strip method was used to resolve discrepancies. RESULTS: The overall categorical agreement between the compared methods reached 99.1% (797/804; 95% CI 98.2%-99.6%), 99.5% (1029/1034; 95% CI 98.9%-99.8%), and 98.8% (2798/2832; 95% CI 98.3%-99.1%) for P. aeruginosa, S. aureus and the Enterobacterales, respectively. CONCLUSIONS: WASPLab incorporating the BioRad expert system provides a fully automated solution for antimicrobial disc diffusion susceptibility testing with equal or better accuracy than other available phenotypic methods.

A molecular based diagnosis of positive blood culture in the context of viral haemorrhagic fever: proof of concept.

OBJECTIVES: The aim of this study was to evaluate the possibility of using a PCR-based panel to identify bacterial and fungal bloodstream infections in the setting of suspected or confirmed viral haemorrhagic fever. METHODS: The accuracy of the FilmArray® Blood Culture Identification Panel (BCID) assay was assessed to identify the common bacterial and fungal pathogens associated with bloodstream infections after positive blood culture inactivation using a guanidinium thiocyanate containing buffer lysis that is commonly used for viral haemorrhagic fever molecular diagnostics. RESULTS: The FilmArray® BCID panel assay detected 95% (19/20) of the pathogens analysed in this study by using both protocols with and without inactivation. Absolute consistency (100%) was observed in all isolates with phenotypes compatible with the presence of the antibiotic resistance genes mecA, vanA, vanB and blaKPC. CONCLUSIONS: The FilmArray® BCID panel assay coupled to inactivation using a guanidinium thiocyanate containing buffer lysis represents a convenient, sensitive and specific diagnostic tool to detect some of the most pathogens associated with bloodstream infections in the context of a suspected or confirmed viral haemorrhagic fever.

Copan WASPLab automation significantly reduces incubation times and allows earlier culture readings.

OBJECTIVE: The aim was to evaluate whether laboratory automation (inoculation and automated incubation combined with timely defined high-resolution digital imaging) may help reduce the time required to obtain reliable culture analysis results. METHODS: We compared the results obtained by WASPLab automation against WASP-based automated inoculation coupled to conventional incubation and manual diagnostic on 1294 clinical samples (483 for the derivation set and 811 for the independent validation set) that included urine, genital tract and non-sterile site specimens, as well as ESwabs for screening of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive Staphylococcus aureus (MSSA), extended-spectrum beta-lactamases (ESBLs) and carbapenemase-producing Enterobacteriaceae (CPE). We used sequential routine specimens referred to the bacteriology laboratory at Geneva University Hospitals between October 2018 and March 2019. RESULTS: The detection sensitivity of MRSA and MSSA at 18 hr on WASPLab was 100% (95% confidence interval [CI], 94.48-100.00%). The detection sensitivity of ESBL and CPE at 16 hr on WASPLab was 100% (95% confidence interval [CI], 94.87% to 100.00%). For urine specimens, the similarity was 79% (295/375) between 18 hr and 24 hr of incubation on WASPLab. For genital tract and non-sterile site specimens, the similarity between 16 hr and 28 hr of incubation on WASPLab were 26% (72/281) and 77% (123/159) respectively. Thus, 28 hr was defined as the final incubation time on WASPLab for genital tract and non-sterile site specimens. CONCLUSIONS: The results of this study show that WASPLab automation enables a reduction of the culture reading time for all specimens tested without affecting performances. Implementing the established and duly validated incubation times will allow appropriate laboratory workflows for improved efficiency to be built.

Clonal or not clonal? Investigating hospital outbreaks of KPC-producing Klebsiella pneumoniae with whole-genome sequencing.

OBJECTIVES: Whole-genome sequencing (WGS) is a promising tool for identifying transmission pathways in outbreaks caused by multidrug-resistant bacteria. However, it is uncertain how the data produced by WGS can be best integrated into epidemiologic investigations. METHODS: We tested various genomic analyses to identify clonal groups in two distinct outbreaks of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae that occurred in Switzerland in 2013 and 2015. In blinded fashion, we sequenced 12 strains involved in the two outbreaks, respectively, and six that were epidemiologically unrelated. We analysed genomic commonalities from conserved genes to plasmid-borne antibiotic resistance genes (ARGs) and contrasted these results with available epidemiologic evidence. RESULTS: Using WGS, blinded analysts correctly identified the two clusters of strains from the two outbreaks. Nonetheless, the 2015 index strain was found to be slightly different (1-3 single nucleotide variants) from the strains recovered from secondary cases, likely because prior long-term carriage (3 years) by the index patient allowed for genetic mutations over time. Also, we observed occasional loss of ARG-bearing plasmidic fragments in outbreak-causing strains. CONCLUSIONS: Retrospective WGS analysis was successful in identifying clonal groups in both outbreaks. Still, data should be analysed with caution in cases of previous long-term carriage of the studied bacteria.

Imipenem heteroresistance in nontypeable Haemophilus influenzae is linked to a combination of altered PBP3, slow drug influx and direct efflux regulation.

OBJECTIVE: To investigate the potential roles of PBPs, efflux pumps and slow drug influx for imipenem heteroresistance in nontypeable Haemophilus influenzae (NTHi). METHODS: Fifty-nine NTHi clinical isolates examined in this study were collected at Geneva University Hospitals between 2009 and 2014. Alterations in PBPs were investigated by gene sequencing. To evaluate the affinities of the PBPs to imipenem, steady-state concentration-response experiments were carried out using imipenem in a competition assay with Bocillin-FL. The effect of the carbonyl cyanide m-chlorophenylhydrazone (CCCP) on imipenem susceptibility was assessed using broth dilution and viable cell counting. Using whole-genome sequencing, we explored the potential roles of outer membrane protein P2 (OmpP2), LytM proteins and the dcw gene cluster in imipenem heteroresistance. RESULTS: All 46 imipenem-heteroresistant isolates (IMIhR) harboured amino acid substitutions in the ftsI gene, which encodes PBP3, corresponding to 25 different mutation patterns that varied from the ftsI gene mutation patterns found in imipenem-susceptible isolates. Among all PBPs, the highest affinity to imipenem was documented for PBP3 (IC50, 0.004 µg/mL). Different amino acid substitutions and insertions were noted in OmpP2, suggesting a relationship with imipenem heteroresistance. The IMIhR isolates were affected by CCCP differently and displayed a higher percentage of killing by imipenem in CCCP-treated cells at concentrations ranging between 0.5 and 8 µg/mL. CONCLUSIONS: The present study provides robust evidence indicating that in combination with the altered PBP3, the slowed drug influx and its enhanced efflux due to the loss of regulation led to the development of imipenem heteroresistance in NTHi.

Rapid molecular determination of methicillin resistance in staphylococcal bacteraemia improves early targeted antibiotic prescribing: a randomized clinical trial.

Empiric therapy of methicillin-susceptible Staphylococcus aureus (MSSA) infections with vancomycin is associated with poorer outcome than targeted therapy with ß-lactams. Our objective was to evaluate whether rapid determination of methicillin resistance shortens the time from Gram stain to targeted antimicrobial therapy in staphylococcal bacteraemia, thereby reducing vancomycin overuse. This was a single-centre open parallel RCT. Gram-positive cocci in clusters in positive blood culture underwent real-time PCR for rapid species and methicillin resistance determination parallel to conventional microbiology. Patients were randomized 1:1 so that clinicians would be informed of PCR results (intervention group) or not (control group). Eighty-nine patients (intervention 48, control 41) were analysed. MRSA was identified in seven patients, MSSA in 46, and CoNS in 36. PCR results were highly concordant (87/89) with standard microbiology. Median time (hours) from Gram stain to transmission of methicillin-susceptibility was 3.9 (2.8-4.3) vs. 25.4 (24.4-26-7) in intervention vs. control groups (p <0.001). Median time (hours) from Gram stain to targeted treatment was similar for 'all staphylococci' [6 (3.8-10) vs. 8 (1-36) p 0.13] but shorter in the intervention group when considering S. aureus only [5 (3-7) vs. 25.5 (3.8-54) p <0.001]. When standard susceptibility testing was complete, 41/48 (85.4%) patients in the intervention group were already receiving targeted therapy compared with 23/41 (56.1%) in the control group (p 0.004). There was no significant effect on clinical outcomes. Rapid determination of methicillin resistance in staphylococcal bacteraemia is accurate and reduces significantly the time to targeted antibiotic therapy in the subgroup of S. aureus, thereby avoiding unnecessary exposure to vancomycin.

Randomized, placebo-controlled, double-blind clinical trial to evaluate the efficacy of polyhexanide for topical decolonization of MRSA carriers.

OBJECTIVES: The objective of this study was to evaluate the efficacy of polyhexanide (Prontoderm(®)) in eliminating MRSA carriage. METHODS: In a 1900 bed teaching hospital, MRSA-colonized patients were randomized into a double-blind, placebo-controlled superiority trial between January 2011 and July 2014. Patients were treated with either polyhexanide or placebo applied to the anterior nares (thrice daily) and skin (once daily) for 10 days. The primary outcome was MRSA decolonization at day 28 (D28) after the end of treatment assessed by ITT responder and PP analyses (microbiological follow-up ± 7 days and topical treatment ≥ 5 days). Secondary outcomes included safety, emergence of resistance and MRSA genotype changes. Registered trial number ISRCTN02288276. RESULTS: Of 2590 patients screened, 146 (polyhexanide group, 71; placebo group, 75) were included. ITT analysis showed that 24/71 (33.8%) patients in the polyhexanide group versus 22/75 (29.3%) in the placebo group were MRSA-free at D28 (risk difference, 4.5%; 95% CI, -10.6% to 19.5%; P = 0.56). PP analysis confirmed the results with 19/53 (35.8%) decolonized polyhexanide-treated patients versus 17/56 (30.4%) in the placebo arm (risk difference, 5.5%; 95% CI, -12.2% to 23%; P = 0.54). Nine serious adverse events occurred in the polyhexanide group versus 12 in the placebo group; none was attributable to study medication. Emergence of polyhexanide resistance or cross-resistance between polyhexanide and chlorhexidine was not observed. No case of exogenous recolonization by a genotypically different MRSA strain was documented. CONCLUSIONS: This study suggests that under real-life conditions, a single polyhexanide decolonization course is not effective in eradicating MRSA carriage.

Ampicillin-resistant Haemophilus influenzae isolates in Geneva: serotype, antimicrobial susceptibility, and ß-lactam resistance mechanisms.

The purpose of this study was to analyze the molecular mechanisms of ampicillin-resistant Haemophilus influenzae isolated in Geneva, Switzerland. We investigated the association between specific patterns of amino acid substitutions in penicillin-binding protein 3 (with or without ß-lactamase production) and ß-lactam susceptibility. Another main focus for this study was to compare the accuracy of disk diffusion and Etest methods to detect resistance to ampicillin and amoxicillin/clavulanic acid. The antibiotic susceptibility to ß-lactam antibiotics of 124 H. influenzae isolates was determined by disk diffusion and Etest methods, and interpreted by European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) breakpoints. Alterations in PBP3 were investigated by sequencing the ftsI gene. Of the 124 clinical isolates analyzed, ampicillin resistance was found in 36% (45 out of 124). The rate of resistance to amoxicillin/clavulanic acid was 9% and 0.8%, using EUCAST and CLSI breakpoints respectively. For the 78 ß-lactamase negative ampicillin-susceptible (BLNAS) isolates for which the Etest method indicated a high degree of susceptibility (MIC ≤ 1 mg/L), the disk diffusion method revealed resistance to ampicillin and amoxicillin/clavulanic acid in 33 cases (42%). Most common amino acid substitutions were Asn526Lys and Val547Ile, followed by Asp569Ser, Ala502Val, Asp350Asn, Met377Ile, Ile449Val, and Arg517His. The patterns observed were classified into six groups (IIa, IIb, IIc, IId, III-like, and miscellaneous). Continued characterization of both invasive and respiratory H. influenzae isolates is necessary in order to observe changes in the microbiology and epidemiology of this pathogen that could lead to clinical failure when treated by empirical antibiotic therapy.

[Diagnosis of bacterial gastroenteritis]. / Diagnostic de la gastroentérite bactérienne.

The etiologic agents of acute gastroenteritis are diverse. The diagnosis of bacterial pathogens is particularly challenging given the large amount of vastly diverse indigenous gastrointestinal organisms present in stool. Multiple methods must be used by the clinical microbiology laboratories to diagnose the cause of acute gastroenteritis, including bacterial cultures, ELISA, and microscopy. Due to the limitations of conventional methods, there is still room for improvement in the detection of pathogens by using the molecular methods. This paper discusses these different diagnostic approaches and limitations.

Polymerase-chain reaction/electrospray ionization-mass spectrometry for the detection of bacteria and fungi in bronchoalveolar lavage fluids: a prospective observational study.

PLEX-ID uses polymerase chain reaction-electrospray ionization/mass spectrometry for rapid identification of infectious agents in clinical samples. We evaluated its concordance with our centre's standard methods (SM) for bacterial and fungal detection in bronchoalveolar lavage (BAL) fluid in a prospective observational cohort study. The primary outcome was concordance (%) between SM and PLEX-ID. Secondary outcomes included concordance when excluding commensal oral flora, detection of resistance genes, and PLEX-ID's potential impact on clinical management, as determined by two independent reviewers. Included were 101 specimens from 94 patients. BALs were performed primarily for suspected pneumonia (76/101, 75%) and lung transplant work-ups (12/101, 12%). Most specimens yielded at least one organism by either method (92/101, 91%). Among all microorganisms detected (n = 218), 83% and 17% were bacterial and fungal, respectively. Overall concordance between SM and PLEX-ID was 45% (45/101). Concordance increased to 66% (67/101) when discordance for commensal flora was excluded. PLEX-ID failed to detect 21% of all 183 SM-identified organisms, while SM did not identify 28% of the 191 PLEX-ID-identified organisms (p <0.001). There was low concordance for mecA detection. Two infectious-disease specialists' analyses concluded that in most of the 31 discordant, non-commensal cases, PLEX-ID results would have had little or no impact on patient management; in eight cases, however, PLEX-ID would have led to 'wrong decision-making'. The tested version of PLEX-ID concurred weakly with standard methods in the detection of bacteria and fungi in BAL specimens, and is not likely to be useful as a standalone tool for microbiological diagnosis in suspected respiratory infections.

[ESBL and carbapenemases in Enterobacteriaceae]. / Bêtalactamases à spectre étendu et carbapénémases chez les Enterobacteriaceae.

Carbapenemase-producing enterobacteria (CPE) spread all over the world during the last years, causing serious infections with increasing frequency. Very few new drugs active against CPE are expected to be clinically available. Studies summarized in this review show that there is yet room to improve our therapeutic approaches, in the treatment of infections due to CPE.

Intrapartum Group B streptococcus detection by rapid polymerase chain reaction assay for the prevention of neonatal sepsis.

Group B streptococcus (GBS) is a leading cause of infectious neonatal morbidity and mortality. Timely and accurate identification of colonized mothers is imperative so that antibioprophylaxis can be implemented during labour to reduce the risk of neonatal sepsis. We planned our study to analyse the diagnostic accuracy of an intrapartum PCR assay to identify GBS-colonized women and to allow the implementation of correct (i.e. at least 4 h) intrapartum antibiotic prophylaxis based on the PCR results. We included 695 women in labour who were tested for rectovaginal GBS carriage by culture and PCR. Women were also screened at 35-37 weeks of gestation. Intrapartum GBS colonization was 19.3%. Assay sensitivity was 81.0% for antenatal culture and 85.0% for intrapartum PCR; p 0.72. GBS colonization (n = 107) was known at least 4 h before delivery in 68 (64%) and 73 (68%) women based on antenatal culture and intrapartum PCR, respectively. Among 43 women delivering preterm, correct status was known at least 4 h before delivery in 10 (23%) and 32 (74%) women according to antenatal culture and intrapartum PCR, respectively. These results support the concept that GBS screening can be performed routinely during labour in a clinical setting. The intrapartum approach is at least as accurate as the antenatal screening, with the additional advantage of identifying women delivering preterm or not followed during pregnancy.

Molecular epidemiology of the nasal colonization by methicillin-susceptible Staphylococcus aureus in Swiss children.

Nasal carriage of Staphylococcus aureus contributes to an increased risk of developing an infection with the same bacterial strain. Genetic regulatory elements and toxin-expressing genes are virulence factors associated with the pathogenic potential of S. aureus. We undertook an extensive molecular characterization of methicillin-susceptible S. aureus (MSSA) carried by children. MSSA were recovered from the nostrils of children. The presence of Panton-Valentine leukocidin (PVL), exfoliatins A and B (exfoA and exfoB), and the toxic-shock staphylococcal toxin (TSST-1) and agr group typing were determined by quantitative PCR. A multiple-locus variable-number of tandem repeat analysis (MLVA) assay was also performed for genotyping. Five hundred and seventy-two strains of MSSA were analysed. Overall, 30% were positive for toxin-expressing genes: 29% contained one toxin and 1.6% two toxins. The most commonly detected toxin gene was tst, which was present in 145 (25%) strains. The TSST-1 gene was significantly associated with the agr group 3 (OR 56.8, 95% CI 32.0-100.8). MLVA analysis revealed a large diversity of genetic content and no clonal relationship was demonstrated among the analysed MSSA strains. Multilocus sequence typing confirmed this observation of diversity and identified ST45 as a frequent colonizer. This broad diversity in MSSA carriage strains suggests a limited selection pressure in our geographical area.

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.

Community-acquired methicillin-resistant Staphylococcus aureus in Switzerland: first surveillance report.

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging community pathogen. Community-acquired MRSA (CA-MRSA) has been associated with virulent strains producing Panton-Valentine leukocidin (PVL) and a variety of other exotoxins. In Geneva, PVL-producing CA-MRSA was first reported in 2002 and a surveillance system based on voluntary reporting was set up. Each MRSA-positive culture result with an antibiotic resistance profile different from the endemic strain prevailing in the Geneva healthcare setting diagnosed in a patient without a history of hospital admission in the previous 12 months was notified to the local health department. A questionnaire was completed by the attending physician with demographic, clinical and exposure information. From January 2002 until December 2004, data on 58 cases were reported, including 26 cases grouped in 13 distinct transmission clusters. Most were family related and for two of them, colonisation persisted over a 12 month period despite treatment. Thirty three patients (57%) were male. Median age was 32 years, 22% being younger than 10 years. Forty one cases (71%) were infected and 17 (29%) colonised. Symptomatic skin lesions such as furunculosis, impetigo or abscess were present in 40 (97%) of the 41 infected cases. Most cases had no underlying disease. Thirty eight cases (65%) had travelled abroad. Forty (69%) of 58 isolates carried the PVL toxin. CA-MRSA infections in Geneva appear to be an emerging problem in the canton. Surveillance should continue and should possibly be extended to other parts of the country to better describe transmission patterns and the spread of this pathogen. Prevention and control of CA-MRSA infections represent a challenge for the future, requiring contact tracing, education and treatment of infected and colonised contacts.

Community-acquired methicillin-resistant Staphylococcus aureus in Switzerland : first surveillance report.

Methicillin resistant Staphylococcus Aureus (MRSA) infection is an emerging community pathogen. Community-acquired MRSA (CA-MRSA) has been associated with virulent strains producing Panton-Valentine leukocidin (PVL) and a variety of other exotoxins. In Geneva, PVL-producing CA-MRSA was first reported in 2002 and a surveillance system based on voluntary reporting was set up.

Use of IgG Avidity test in case definitions of toxoplasmosis in pregnancy.

A survey network for congenital toxoplasmosis (TOXO-NET) was set up in December 1996 in Piedmont (Italy). Participants were asked to classify the infections in pregnant mothers and newborns by the criteria of the European Network on Congenital Toxoplasmosis published by Lebech in 1996. Because the IgG Avidity test is largely employed as a 2nd level test in toxoplasmosis diagnosis and it could be helpful to date infection, the co-ordinators of TOXO-NET suggested including it in the "case definition" of "probable" infection and "unlikely" infection. 117 cases of toxoplasmosis in pregnancy divided into the risk categories under Lebech's criteria were re-examined using the "new" case definitions. 77 out of 117 (65.8%) Toxoplasma gondii infections during pregnancy could be defined with only one serum sample using the IgG Avidity test. The IgG Avidity test proved a useful method to classify the Toxoplasma gondii infections in pregnancy, especially when we had only one serum sample.