Clinical standards for the diagnosis, treatment and prevention of TB infection

BACKGROUND: Tuberculosis (TB) preventive therapy (TPT) decreases the risk of developing TB disease and its associated morbidity and mortality. The aim of these clinical standards is to guide the assessment, management of TB infection (TBI) and implementation of TPT.METHODS: A panel of global experts in the field of TB care was identified; 41 participated in a Delphi process. A 5-point Likert scale was used to score the initial standards. After rounds of revision, the document was approved with 100% agreement.RESULTS: Eight clinical standards were defined: Standard 1, all individuals belonging to at-risk groups for TB should undergo testing for TBI; Standard 2, all individual candidates for TPT (including caregivers of children) should undergo a counselling/health education session; Standard 3, testing for TBI: timing and test of choice should be optimised; Standard 4, TB disease should be excluded prior to initiation of TPT; Standard 5, all candidates for TPT should undergo a set of baseline examinations; Standard 6, all individuals initiating TPT should receive one of the recommended regimens; Standard 7, all individuals who have started TPT should be monitored; Standard 8, a TBI screening and testing register should be kept to inform the cascade of care.CONCLUSION: This is the first consensus-based set of Clinical Standards for TBI. This document guides clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage TBI.

Impact of 24/7 loading of blood culture bottles in a new automated incubator on the diagnosis of bloodstream infections

Blood culturing (BC) remains the gold standard for bloodstream diagnosis but its workflow is slow. We aimed reducing this time by implementing a new automated incubator with a 24/7 BC workflow. With this new strategy, time to incubation was shorter (1.52 h vs 6.82 h), positivity rates were higher (10.6% vs 8.9%, p<0.05), and the number of BSI diagnostics increased (16.1% vs 13.8% patients and 2.3 vs 1.9 density episode per 1000 hospital days). Our results show that implementing automatic loading of BC bottles with a 24/7 strategy not only shortened time to diagnosis but significantly increased the BSI diagnosis rate.

Sniffing animals as a diagnostic tool in infectious diseases

BACKGROUND

Scents and odours characterize some microbes when grown in the laboratory, and experienced clinicians can diagnose patients with some infectious diseases based on their smell. Animal sniffing is an innate behaviour, and animals' olfactory acuity is used for detecting people, weapons, bombs, narcotics and food.

OBJECTIVES

We briefly summarized current knowledge regarding the use of sniffing animals to diagnose some infectious diseases and the potential use of scent-based diagnostic instruments in microbiology.

SOURCES

Information was sought through PubMed and extracted from peer-reviewed literature published between January 2000 and September 2019 and from reliable online news. The search terms 'odour', 'scent', 'bacteria', 'diagnostics', 'tuberculosis', 'malaria' and 'volatile compounds' were used.

CONTENT

Four major areas of using sniffing animals are summarized. Dogs have been used to reliably detect stool associated with toxigenic Clostridioides difficile and for surveillance. Dogs showed high sensitivity and moderate specificity for detecting urinary tract infections in comparison to culture, especially for Escherichia coli. African giant pouched rats showed superiority for diagnosing tuberculosis over microscopy, but inferiority to culture/molecular methods. Several approaches for detecting malaria by analysing host skin odour or exhaled breath have been explored successfully. Some microbial infections produce specific volatile organic compounds (VOCs), which can be analysed by spectrometry, metabolomics or other analytical approaches to replace animal sniffing.

IMPLICATIONS

The results of sniffing animal studies are fascinating, and animal sniffing can provide intermediate diagnostic solutions for some infectious diseases. Lack of reproducibility, and cost of animal training and housing are major drawbacks for wider implementation of sniffing animals. The ultimate goal is to understand the biological background of this animal ability and to characterize the specific VOCs that animals are recognizing. VOC identification, improvement of odour sampling methods and development of point-of-care instruments could allow implementation of scent-based tests for major human pathogens.

Determination of Escherichia coli phylogroups in elderly patients with urinary tract infection or asymptomatic bacteriuria

OBJECTIVES

Distinguishing between urinary tract infection (UTI) and asymptomatic bacteriuria (ABU) is difficult in the geriatric population since specific symptoms are often lacking. Escherichia coli is the most frequent UTI pathogen in this population but also a common urine colonizer. We hypothesized that detecting E. coli phylogroups B2 or D, which were previously associated with virulent strains responsible for extra-intestinal infections outside elderly patients, could help in distinguishing UTI from ABU.

METHODS

Consecutive cases of E. coli bacteriuria diagnosed in hospitalized patients >75 years old during 3 months were investigated for E. coli phylogroups. Multiplex PCR was used to search for several virulence genes as previously described. Characteristics of UTI and ABU cases, assessed retrospectively according to definitions and geriatric expertise, were compared.

RESULTS

Out of 233 bacteriuria cases, 60 were assessed to be UTI and 163 to be ABU, with 10 cases unclassified. E. coli strains belonging to the phylogroups B2 and D were significantly more frequent in UTI (48/60, 80%) than in ABU (101/163, 62%) by univariate and multivariate analyses (OR 3.05, 1.44-6.86, p 0.005). Out of all the host and bacterial characteristics studied, falls (p 0.032), comorbidities (p 0.041), and altered autonomy evaluated by a low activity of daily living score (p 0.027) were also associated with UTI using univariate and multivariate analysis.

CONCLUSIONS

Determination of the E. coli phylogroup, in addition to some host characteristics, can help to distinguish UTI from ABU in elderly patients with bacteriuria. If this hypothesis is confirmed by prospective studies, then inappropriate use of antibiotics may be reduced in ABU cases.

Antimicrobial resistance in leprosy: results of the first prospective open survey conducted by a WHO surveillance network for the period 2009-15

OBJECTIVES

Antimicrobial resistance (AMR) is a priority for surveillance in bacterial infections. For leprosy, AMR has not been assessed because Mycobacterium leprae does not grow in vitro. We aim to obtain AMR data using molecular detection of resistance genes and to conduct a prospective open survey of resistance to antileprosy drugs in countries where leprosy is endemic through a WHO surveillance network.

METHODS

From 2009 to 2015, multi-bacillary leprosy cases at sentinel sites of 19 countries were studied for resistance to rifampicin, dapsone and ofloxacin by PCR sequencing of the drug-resistance-determining regions of the genes rpoB, folP1 and gyrA.

RESULTS

Among 1932 (1143 relapse and 789 new) cases studied, 154 (8.0%) M. leprae strains were found with mutations conferring resistance showing 182 resistance traits (74 for rifampicin, 87 for dapsone and 21 for ofloxacin). Twenty cases showed rifampicin and dapsone resistance, four showed ofloxacin and dapsone resistance, but no cases were resistant to rifampicin and ofloxacin. Rifampicin resistance was observed among relapse (58/1143, 5.1%) and new (16/789, 2.0%) cases in 12 countries. India, Brazil and Colombia reported more than five rifampicin-resistant cases.

CONCLUSIONS

This is the first study reporting global data on AMR in leprosy. Rifampicin resistance emerged, stressing the need for expansion of surveillance. This is also a call for vigilance on the global use of antimicrobial agents, because ofloxacin resistance probably developed in relation to the general intake of antibiotics for other infections as it is not part of the multidrug combination used to treat leprosy.

Connectivity of diagnostic technologies: improving surveillance and accelerating tuberculosis elimination

In regard to tuberculosis (TB) and other major global epidemics, the use of new diagnostic tests is increasing dramatically, including in resource-limited countries. Although there has never been as much digital information generated, this data source has not been exploited to its full potential. In this opinion paper, we discuss lessons learned from the global scale-up of these laboratory devices and the pathway to tapping the potential of laboratory-generated information in the field of TB by using connectivity. Responding to the demand for connectivity, innovative third-party players have proposed solutions that have been widely adopted by field users of the Xpert(®) MTB/RIF assay. The experience associated with the utilisation of these systems, which facilitate the monitoring of wide laboratory networks, stressed the need for a more global and comprehensive approach to diagnostic connectivity. In addition to facilitating the reporting of test results, the mobility of digital information allows the sharing of information generated in programme settings. When they become easily accessible, these data can be used to improve patient care, disease surveillance and drug discovery. They should therefore be considered as a public health good. We list several examples of concrete initiatives that should allow data sources to be combined to improve the understanding of the epidemic, support the operational response and, finally, accelerate TB elimination. With the many opportunities that the pooling of data associated with the TB epidemic can provide, pooling of this information at an international level has become an absolute priority.

Monitoring antimicrobial resistance (AMR) using CUSUM control charts

We evaluated the use of the Cumulative Summation (CUSUM) control chart methodology for detection of an excessive increase in antimicrobial-resistant (AMR) bacteria acquisition. We used administrative, clinical and bacteriological data from all 157,570 patients hospitalized for at least 48 h from January 1, 2010 to December 31, 2015 in a 654-bed university teaching hospital in Paris, France. Monthly computed CUSUM were evaluated for the detection of out-of-control situations, defined as incidence rates of acquired AMR bacterial colonization exceeding acceptable thresholds at the hospital and ward levels (based on six selected wards) for AMR bacteria overall and Extended-spectrum beta-lactamases Enterobacteriaceae (ESBL-E) and Methicillin-resistant Staphylococcus aureus (MRSA), specifically. During the study period, 1,403 samples of acquired AMR bacteria were identified including 1,129 ESBL-E and 151 MRSA. The incidence rate of acquired AMR bacteria was stable at the hospital and the wards level. When based on AMR bacteria overall, CUSUM alarms were triggered at the hospital level and at the ward level in four units. For ESBL-E, CUSUM tests generated alarms at the hospital level and for the same four wards, and for MRSA, CUSUM tests detected out-of-control situations in all the wards. The CUSUM approach appears complementary with hospital infection control strategies currently in practice and appears of interest in common practice as a simple tool for AMR surveillance.

Mycobacterium tuberculosis drug-resistance testing: challenges, recent developments and perspectives

Drug-resistance testing, or antimicrobial susceptibility testing (AST), is mandatory for Mycobacterium tuberculosis in cases of failure on standard therapy. We reviewed the different methods and techniques of phenotypic and genotypic approaches. Although multiresistant and extensively drug-resistant (MDR/XDR) tuberculosis is present worldwide, AST for M. tuberculosis (AST-MTB) is still mainly performed according to the resources available rather than the drug-resistance rates. Phenotypic methods, i.e. culture-based AST, are commonly used in high-income countries to confirm susceptibility of new cases of tuberculosis. They are also used to detect resistance in tuberculosis cases with risk factors, in combination with genotypic tests. In low-income countries, genotypic methods screening hot-spot mutations known to confer resistance were found to be easier to perform because they avoid the culture and biosafety constraint. Given that genotypic tests can rapidly detect the prominent mechanisms of resistance, such as the rpoB mutation for rifampicin resistance, we are facing new challenges with the observation of false-resistance (mutations not conferring resistance) and false-susceptibility (mutations different from the common mechanism) results. Phenotypic and genotypic approaches are therefore complementary for obtaining a high sensitivity and specificity for detecting drug resistances and susceptibilities to accurately predict MDR/XDR cure and to gather relevant data for resistance surveillance. Although AST-MTB was established in the 1960s, there is no consensus reference method for MIC determination against which the numerous AST-MTB techniques can be compared. This information is necessary for assessing in vitro activity and setting breakpoints for future anti-tuberculosis agents.

Incidence of gonococcal and chlamydial infections and coverage of two laboratory surveillance networks, France, 2012

Surveillance of sexually transmitted diseases in France is based on voluntary networks of laboratories and clinicians. Despite the importance of incidence data in improving knowledge about the national context and in international comparisons, such data were not previously available. During nationwide quality control of laboratories, mandatory for all laboratories, we conducted a survey in June 2013 to estimate the incidence rates of gonococcal and chlamydial infections for 2012 and to estimate the proportion of diagnoses performed (coverage) by the country's two laboratory-based sentinel networks for these diseases. Estimated incidence rates for 2012 were 39 per 100,000 persons aged 15 to 59 years for gonorrhoea and 257 per 100,000 persons aged 15 to 49 years for chlamydia. These rates were consistent with the average levels for a group of other Western countries. However, different estimates between countries may reflect disparate sources of surveillance data and diverse screening strategies. Better comparability between countries requires harmonising data sources and the presentation of results. Estimated coverage rates of the gonococcal and chlamydial infection surveillance networks in France in 2012 were 23% and 18%, respectively, with substantial regional variations. These variations justify improving the representativeness of these networks by adding laboratories in insufficiently covered areas.

Incidence of gonococcal and chlamydial infections and coverage of two laboratory surveillance networks, France, 2012

Binary file ES_Abstracts_Final_ECDC.txt matches

Steps towards the discovery of Mycobacterium tuberculosis by Robert Koch, 1882

Palaeomicrobiology has detected the tuberculosis agent in animal and human skeletons that are thousands of years old. The German doctor Robert Koch was the first microbiologist to report in 1882 the successful isolation of the causative agent of tuberculosis, named 1 year later as Mycobacterium tuberculosis. This immense discovery, however, was not made from scratch, but involved the combining of previous scientific knowledge, chiefly the previous demonstration by the French doctor Jean-Antoine Villemin that tuberculosis was a transmissible disease, and two innovations--a new staining procedure that allowed R. Koch to consistently observe the new organism in tuberculous lesions, and use of a solidified, serum-based medium instead of broths for the culture. These innovations allowed R. Koch not only to isolate M. tuberculosis from animal and patient specimens for the first time, but also to reproduce the disease in experimentally inoculated guinea pigs. It is thanks to R. Koch that one of the most lethal diseases in human history could be diagnosed, could be treated and cured after the discovery of streptomycin 65 years later, and could be efficiently prevented by isolation of cases. His microbiological innovations are now being renewed with molecular and improved culture-based detection being the twenty-first century weapons in the fight against this disease, which remains a major killer.

Revisiting susceptibility testing in MDR-TB by a standardized quantitative phenotypic assessment in a European multicentre study

OBJECTIVES

Treatment outcome of MDR-TB is critically dependent on the proper use of second-line drugs as per the result of in vitro drug susceptibility testing (DST). We aimed to establish a standardized DST procedure based on quantitative determination of drug resistance and compared the results with those of genotypes associated with drug resistance.

METHODS

The protocol, based on MGIT 960 and the TB eXiST software, was evaluated in nine European reference laboratories. Resistance detection at a screening drug concentration was followed by determination of resistance levels and estimation of the resistance proportion. Mutations in 14 gene regions were investigated using established techniques.

RESULTS

A total of 139 Mycobacterium tuberculosis isolates from patients with MDR-TB and resistance beyond MDR-TB were tested for 13 antituberculous drugs: isoniazid, rifampicin, rifabutin, ethambutol, pyrazinamide, streptomycin, para-aminosalicylic acid, ethionamide, amikacin, capreomycin, ofloxacin, moxifloxacin and linezolid. Concordance between phenotypic and genotypic resistance was >80%, except for ethambutol. Time to results was short (median 10 days). High-level resistance, which precludes the therapeutic use of an antituberculous drug, was observed in 49% of the isolates. The finding of a low or intermediate resistance level in 16% and 35% of the isolates, respectively, may help in designing an efficient personalized regimen for the treatment of MDR-TB patients.

CONCLUSIONS

The automated DST procedure permits accurate and rapid quantitative resistance profiling of first- and second-line antituberculous drugs. Prospective validation is warranted to determine the impact on patient care.

High-level azithromycin-resistant Neisseria gonorrhoeae clinical isolate in France, March 2014

We report the first case in France of a high-level azithromycin-resistant Neisseria gonorrhoeae (minimum inhibitory concentration (MIC) = 96 mg/L) assigned to MLST7363 (NG-MAST ST6360), also resistant to ciprofloxacin and tetracycline but susceptible to ceftriaxone. The patient was a 51 year-old heterosexual man who returned following 1g azithromycin monotherapy. Mechanisms of azithromycin resistance were a C2599T mutation in the four copies of the rrl gene and a novel mutation in the promoter of the mtrR gene.

Gonococcal infections and emergence of gonococcal decreased susceptibility to cephalosporins in France, 2001 to 2012

Resistance to cephalosporins may lead to untreatable gonococcal infections. We describe the results of the sentinel surveillance of gonococcal infections and the evolution of the resistance of Neisseria gonorrhoeae to antibiotics in France from 2001 to 2012. We also analyse the factors associated with decreased susceptibility to third generation cephalosporins. In France, surveillance of gonococcal infections is conducted through a network of voluntarily participating laboratories. Strains are sent to the national reference laboratory to determine the minimum inhibitory concentration (MIC) for six antibiotics. During the study period, the number of gonococcal infections increased steadily. The susceptibility of 8,649 strains was studied for this period. The proportion of strains with decreased susceptibility to cefixime (MIC>0.125 mg/L) quadrupled between 2011 (0.7%:10/1,521) and 2012 (3.0%: 33/1,093; p<0.001). Between 2001 and 2012, only two of the 8,649 strains, both collected in 2010, had a MIC>0.125 mg/L for ceftriaxone. Decreased susceptibility to cephalosporins increased with older age and was more common in pharyngeal strains. Decreased susceptibility to cefixime may indicate that the national recommendation to use ceftriaxone as a first line treatment for cases of urethritis and cervicitis has not been fully implemented. Enhanced surveillance of pharyngeal strains is strongly suggested.

Disseminated cutaneous infection due to Mycobacterium chelonae following hematopoietic stem cell transplantation

This report describes two cases of disseminated cutaneous Mycobacterium chelonae after hematopoietic stem cell transplantation (HSCT).

Antimicrobials that affect the synthesis and conformation of nucleic acids

Several antimicrobials act by inhibiting the synthesis of nucleic acids (rifamycins, sulfamides, diaminopyridines), modifying their conformation (quinolones, coumarins) or causing irreversible lesions (nitroimidazoles, nitrofurans). The resistance mechanisms are: a reduction in intracytoplasmic accumulation, modification of the target or the production of a new low-affinity target and, more rarely, enzyme inactivation. Although the mechanisms affecting the targets are specific to each family and can lead to high-level resistance, the reduced permeability of the membrane and the increased efflux are non-specific and result in low-level cross-resistance between several families. The genetic mediation is usually chromosomal for rifamycins and quinolones, although plasmid-mediated resistant genes have been observed. On the other hand, for sulfamides and trimethoprim, plasmid-borne genes are frequent. Resistance to nitroimidazoles and nitrofurans is still not widely understood.

In vivo selection of a complex mutant TEM (CMT) from an inhibitor-resistant TEM (IRT) during ceftazidime therapy

OBJECTIVES

A relapse from Escherichia coli bloodstream infection was observed in a patient with acute leukaemia treated with ceftazidime for 7 days for febrile neutropenia. Whereas the original E. coli isolate was resistant to β-lactam/β-lactamase inhibitor combinations (EC1), the relapse E. coli isolate showed a similar phenotype but with resistance extended to ceftazidime (EC2). We investigated the molecular mechanisms of β-lactam resistance and sought if EC2 could have been selected in vivo from EC1.

METHODS

EC1 and EC2 isolates were compared for antibiotic MICs, plasmid content, genotyping, β-lactamase genes and their environment. Both isolates were conjugated with E. coli JW4111ΔampC and MICs determined for transconjugants. In addition, ceftazidime-resistant mutants were selected in vitro from EC1.

RESULTS

EC1 and EC2 showed identical patterns for genotyping and resistance plasmids. PCR sequencing of blaTEM in EC1 showed the mutations M69L and N276D corresponding to TEM-35, also called inhibitor-resistant TEM (IRT)-4. In EC2, the TEM allele showed an additional mutation, R164S, known to confer resistance to ceftazidime. The combination of these three mutations was previously reported in TEM-158, described as the complex mutant TEM (CMT)-9, associated with resistance to β-lactamase inhibitors and third-generation cephalosporins. In vitro selection of ceftazidime-resistant mutants from EC1 yielded six different CMT alleles, including TEM-158 containing the R164S mutation.

CONCLUSIONS

This first known report of in vivo selection of CMT from IRT, reproduced in vitro, shows how the evolution of β-lactamase enzymes is easily driven by antibiotic pressure, even during a short antibiotic therapy.

Prosthetic knee arthritis due to Granulicatella adiacens after dental treatment

We report prosthetic knee arthritis in a 55-year-old diabetic man due to Granulicatella adiacens, a micro-organism present in the oral flora, usually described in endocarditis but rarely in prosthesis joint infection. This patient had undergone a dental extraction without antibiotic prophylaxis one month before, and an aseptic loosening of the prosthesis had been diagnosed previously. If antimicrobial prophylaxis against infective endocarditis for dental procedures is well established, such an approach is still controversial for joint prosthesis and should be considered in some conditions.

[Histopathological study of Mycobacterium marinum infection]

INTRODUCTION

Skin infection by Mycobacterium marinum induces the classic granuloma of aquariums and swimming pools. The histopathological signs have been described primarily in small series of typical cases, generally with no bacteriological evidence. In a national survey of proven infection with M. marinum detailed data was collected for 63 patients. The aim of this new study was to describe microscopic signs of the infection based upon biopsies taken from these patients.

PATIENTS AND METHODS

Unstained slides from 32 biopsies of the skin (n=24) or synovial biopsies (n=8) were prepared; they originated from 27 patients. They were examined after standard staining and after Ziehl-Neelsen staining, without knowledge of the clinical data.

RESULTS

All biopsies were taken from the upper limb of 18 men and nine women of mean age 48 years. Tubercular granulomas were observed in only 60% of cases. The largest and most numerous were seen in the synovial samples. Due to their palisade appearance, they were occasionally impossible to distinguish from rheumatoid nodules. In 20% of cases, neutrophil collections were seen without granulomas and in remaining 20% of cases, relatively non-specific infiltrate was observed. Epidermal changes consisted in psoriasiform or pseudocarcinomatous hyperplasia, particularly at the edges of ulcerated areas; invasion of the dermo-epidermal junction was seen in five cases. Follicular necrosis was observed in four cases with lymphoplasmacytic infiltrates remote from the granulomas being seen in 22 biopsies. Ziehl-Neelsen staining revealed no bacilli.

DISCUSSION

The originality of this series consists of bacteriological proof of M. marinum infection and the absence of biopsy selection based on clinical criteria. It shows that the typical granulomas are in fact present in less than two third of cases, and that these may be confused with rheumatoid nodules. The chief characteristic of these lesions is the very low concentration of microorganisms present, in contrast with other forms of mycobacterium, making them difficult to see; routine confirmation cannot thus be expected from specific staining procedures. In one case out of five, the infiltrate suggested no infectious origin, although deep skin biopsies and synovial biopsies provided more information. For all forms of necrotic granuloma, whether or not accompanied by collections of neutrophils, a culture should be carried out in a specific medium, even in the absence of microscopic evidence of bacilli.

[Real-time PCR for fast detection of plasmid-mediated qnr genes in extended spectrum beta-lactamase producing Enterobacteriaceae]

AIM OF THE STUDY

To develop a fast and reliable real time PCR technique for detecting plasmid-mediated quinolone resistance genes qnrA, qnrB and qnrS.

METHODS

A real-time PCR assay using SYBR Green I and Roche LightCycler(®) was developed to detect qnr genes. Detection of qnr genes was based on comparison of melting temperature differences with a positive control of each qnr genes. This assay was performed to study 138 isolates collected from diagnostic and screening samples in the Champagne-Ardenne region in 2004 (France).

RESULTS

In optimized conditions, the three positive controls tested alone and with isolates confirmed the specificity of the PCR primers. Each PCR assay was able to test 30 strains in 60min for 1 qnr gene. Out of 138 isolates screened, 3.6 % isolates were positive for a qnrA1, 1.5 % for qnrS1 and no qnrB-like gene. Prevalence of qnr determinants was 5 % and reached 9.5 % in clinical isolates.

CONCLUSION

Real-time PCR is a fast and reliable technique for screening of qnr-positive strains. This study shows a relatively high prevalence of qnr determinants (5 %) among ESBL-producing Enterobacteriaceae.

Nationwide survey of extended-spectrum {beta}-lactamase-producing Enterobacteriaceae in the French community setting

OBJECTIVES

The aim of this study was to assess the prevalence of the extended-spectrum beta-lactamase (ESBL)-producing enterobacteria (ESBLE) in the French community, during a 2006 survey.

METHODS

All enterobacteria isolated from urine samples of patients, exhibiting a decreased susceptibility to broad-spectrum cephalosporins, were analysed for their beta-lactamase content (synergy test, isoelectrofocusing, conjugation transfer, PCR amplification and/or cloning experiments and sequencing). Additional co-resistances were investigated by PCR, sequencing and/or cloning. Epidemiological relationship was studied by PFGE for all species and, in addition, for Escherichia coli by the determination of the phylogenetic group, multilocus sequence type (ST) and O25b antigen. Characteristics of CTX-M-producing E. coli carriers were compared with other ESBLE carriers.

RESULTS

Seventy-two ESBLE were collected from 71 patients. Most of them expressed a CTX-M enzyme (n = 42, comprising 40 E. coli), with a predominance of CTX-M-15 (n = 24); 10 CTX-M-15-producing E. coli belonged to the same clone (phylogroup B2, ST131, serotype O25b). The 30 remaining strains possessed a TEM- or SHV-type ESBL. In addition, three strains presented unusual co-resistances such as DHA-1 (n = 2), QnrB4 and ArmA. Risk factors for ESBLE acquisition were substantially less frequent when the ESBL was of the CTX-M type, except for prior antimicrobial therapy. Eighteen percent of the patients were considered to have true community-acquired ESBLE; most of them harboured a CTX-M-producing E. coli.

CONCLUSIONS

This first nationwide study reports an ESBLE prevalence of 1.1% in the French community setting in 2006, mainly related to the presence of CTX-M-producing E. coli strains; furthermore, unusual co-resistances rarely found in the community setting were occasionally observed, which may threaten future emergence.

Incidence et caractéristiques cliniques des infections urinaires symptomatiques dans un hôpital gériatrique

OBJECTIVES AND SETTINGS: The authors had for aim to study the incidence of symptomatic urinary infections (SUTI) in elderly patients, to describe their clinical and microbiologic characteristics and first-line treatment in a geriatric hospital with 902 beds: 124 in acute care (ACF), 293 in rehabilitation and intermediate-care (RICF), and 485 in long-term-care-facilities (LTCF).

METHOD

During two months in 2003, all positive urine cultures detected by the laboratory were sent to the clinician with a questionnaire on clinical signs, diagnosis of SUTI and antibiotic treatment.

RESULTS

SUTI was diagnosed in 85 out of 204 positive urine cultures (40%). The incidence of SUTI was 1.86 per 1,000 patient-days (with rates of 2.63, 2.49, 1.41 per 1,000 patients-days for the ACF, RICF, LTCF respectively). For 51 cases (60%) there were only general symptoms, for 24 cases (28.2%) there were only urinary symptoms, and for 10 cases (11.8%) there were both. Escherichia coli and Proteus mirabilis were the main bacterial species involved in 57 and 14% respectively. E. coli strains were 59% resistant to amoxicillin, 55% resistant to amoxicillin-clavulanic acid, and 39% resistant to fluoroquinolones. The main antibiotics were fluoroquinolones, ceftriaxone, and amoxicillin-clavulanate, prescribed respectively in 52.5, 19, and 9% of the cases.

CONCLUSION

SUTI was diagnosed in only in 40% of positive urine cultures from elderly patients hospitalized in our hospital. To improve the management of SUTI in this population, we changed our recommendations for diagnosis and treatment.

Occurrence of qnrA-positive clinical isolates in French teaching hospitals during 2002-2005

Bacteria harbouring the novel qnrA plasmid-mediated mechanism of quinolone resistance have been described in different countries, but the frequency of their occurrence has not been investigated. In total, 1,468 clinical isolates of Enterobacteriaceae with quinolone resistance or extended-spectrum beta-lactamase (ESBL) phenotypes were collected from eight teaching hospitals in France during 2002-2005 and screened for qnrA. Overall, 28 isolates (22 Enterobacter cloacae, three Klebsiella pneumoniae, one Citrobacter freundii, one Klebsiella oxytoca and one Proteus mirabilis) were positive for qnrA, representing 1.9% of all isolates, 3.3% of ESBL-producing isolates (22% of the E. cloacae isolates) and 0% of non-ESBL-producing isolates. The prevalence of qnrA among consecutive ESBL-producing isolates in 2004 from the eight hospitals was 2.8% (18/639). Of the qnrA-positive isolates, 100% were intermediately-resistant or resistant to nalidixic acid, and 75% to ciprofloxacin. Twenty-one of the 22 qnrA-positive E. cloacae isolates were obtained from two hospitals in the Paris area, and molecular typing and plasmid content analysis showed clonal relationships for five, three and two isolates, respectively. The qnrA genetic environment was similar to that of the In36 integron. The remaining two isolates had qnrA variants (30 and 29 nucleotide differences, respectively, compared with the original sequence) and an unknown genetic environment. The ESBL gene associated with qnrA was bla(SHV-12) in most of the isolates, but bla(PER-1) and bla(SHV-2a) were found in two isolates. In France, it appears that qnrA-positive isolates are predominantly E. cloacae isolates producing SHV-12, and may be associated with the dissemination of an In36-like integron.

[Investigation of the new QNR-based mechanism of quinolone resistance among enterobacterial strains isolated in Henri-Mondor hospital 2002-2005]

AIM OF THE STUDY

To assess the prevalence of the novel plasmid-mediated resistance to quinolones in enterobacteria isolated in our hospital.

MATERIALS AND METHODS

We have screened 737 enterobacterial strains isolated in Henri-Mondor hospital between 2002 and 2005 for the presence of the qnr gene by PCR using specific primers. Among them, 282 had a phenotype in concordance with extended spectrum betalactamase (ESBL). Qnr-positive strains were phenotypically and genetically characterized, and epidemiological link between the cases was investigated.

RESULTS

Five qnr+ strains were described. The global prevalence was 0.7% but 5/282 among ESBL producing strains and 0/437 among quinolone-resistant enterobacteria non producing ESBL. The sequences of the PCR products were identical to qnrA in the environment of the integron In36. All the strains harboured also the ESBL SHV-12 gene. Transfer of qnr by conjugation raised quinolone MICs from 2 to 24 times. However clinical strains harboured a higher level of quinolone resistance and harboured also DNA gyrase and topoisomerase IV mutations. Two strains were epidemiologically related by molecular typing and contact tracing revealed that the patients have been previously hospitalized in the same tertiary care center.

CONCLUSION

We described the first investigation of qnr-positive strains in one hospital in France over 4 years. Although the qnr gene prevalence is low, nosocomial transmission is already shown and the transfer of the qnr containing integron among ESBL producing strains may predict future epidemic. Surveillance will be necessary to confirm this low prevalence rate of qnr in France.

Résistance aux antituberculeux

Mycobacteria responsible for tuberculosis (M. tuberculosis, M. bovis, M. africanum) are susceptible to a very small number of antibiotics. As soon as these drugs were used in humans all gave rise to the selection of resistant mycobacteria. Study of the mechanisms of acquired resistance, with the help of the genetics of mycobacteria, led to a more accurate understanding of the mode of action of antituberculous drugs. The antibiotics isoniazid, pyrazinamide, ethionamide and ethambutol are mycobacteria-specific because they inhibit the synthesis of mycolic acids, which are specific constituants of the bacterial wall. Mutations responsible for resistance to these drugs affect genes coding for activator enzymes (katg for isoniazid, pncA for pyrazinamide) or genes coding for their target (inhA for isoniazid/ethionamide, embB for ethambutol). With rifamycins, aminosides and quinolones, mechanisms of action and resistance are the same for mycobacteria as for non-mycobacterial organisms. No plasmid or resistance transposon has been described in M. tuberculosis. Currently a test for the quick detection of resistance to rifampicin is widely available but in the future DNA chips may allow the simultaneous detection of multiple resistances. Monitoring of antituberculous drugs shows that in France the prevalence of multiresistance ( resistance to both isoniazid and rifampicin) is 0.5%, primary resistance (before treatment) is 9%, and secondary resistance (after treatment) is 16%.

Étude descriptive des bactériémies dans un hôpital gériatrique universitaire

OBJECTIVES

To describe clinical features, microbiologic characteristics and outcome of bacteremia in the elderly patients hospitalized in a geriatric hospital.

PATIENTS AND METHODS

All episodes of bacteremia diagnosed from January 1(st) to December 31(st) 1998 were analysed, excluding false-positive cases due to skin contamination. The hospital comprises 1084 geriatric beds distributed as 111 in acute care (ACF), 333 in rehabilitation and intermediate-care (RICF), and 516 in long-term-care facilities (LTCF).

RESULTS

Sixty-six episodes of bacteremia were observed in 65 patients. Among them 59 (89%) were nosocomial bacteremia distributed as 20 in ACF, 29 in RICF and 10 in LTCF (rates of 0.6, 0.35, and 0.05 episodes per 1000 patient-days, respectively.). Escherichia coli and Staphylococcus aureus were the main bacterial species involved in 31% and 28% of the cases, respectively. E. coli strains were 50% resistant to amoxicillin and 41% resistant to co-amoxiclav, and 68% of S. aureus strains were resistant to methicillin. Portals of entry were urinary tract (44%), respiratory tract (14%), digestive tract (11%), and soft tissue (8%). The same bacterial strain as in bacteremia was isolated from a peripheric site in 30 cases (47%), most of them being urines. For 15% cases, portal of entry cannot be determined. Mortality associated to nosocomial bacteremia was 25%, and death was significantly associated to MRSA, urinary or intravascular devices, chronic wounds and inappropriate antibiotic prescription.

CONCLUSION

In geriatric hospitals, bacteremia are mainly nosocomial cases. Prevention should focus on indwelling devices and antibiotic resistance.

Épidémiologie et résistance aux antibiotiques de Streptococcus pneumoniae en Île de France en 2001

OBJECTIVE

The authors wanted to assess the level of Streptococcus pneumoniae antibiotic resistance in Ile de France.

METHOD

In 2001, 637 clinical strains of S. pneumoniae were prospectively collected from 32 microbiology laboratories.

RESULTS

Fifty one percent of strains were isolated from children under 15 years of age and 49% from adults. In children, 76% of strains came from otitis media, 20% from blood culture, in adults most strains (92%) came from blood culture. The overall prevalence of non-susceptible penicillin pneumococci was 61% higher in children (73%) than in adults (50%). Among the non-susceptible penicillin pneumococci 21.8% were resistant (CMI > 1 mg/l). Strains with decreased susceptibility to amoxicillin and cefotaxime were 38% and 17% respectively. Resistant strains to these two drugs (CMI > 2 mg/l) were rare 2.6% and 0.4% respectively. Among other antimicrobial agents, rate of resistance was 63% to erythromycin, 47% to cotrimoxazole, 40% to tetracycline, and 23% to chloramphenicol. The most frequent serogroups were serogroups 19 and 14, respectively 23% and 18%. Serotypes included in heptavalent vaccine covered 90% of children strains under 2 years of age.

CONCLUSIONS

The prevalence of resistance to penicillin was high in children particularly in otitis media pus (76%).

[Evolution of susceptibility of aerobic gram-negative aerobic bacilli to quinolones and fluoroquinolones in a university hospital (1992-2000)]

Susceptibility to quinolones of aerobic gram-negative bacilli was assessed in a 2000-bed university hospital from 1992 to 2000. There was a significant downward trend in the rate of susceptibility to nalidixic acid (Nal) for Enterobacteriaceae as a whole from 1992 to 2000 (86% vs 82%), and E. coli (92% vs 84%), and an upward trend for K. pneumoniae (74% vs 82%), the latter being related to the control of the spread of epidemic ESBL producing strains. The overall susceptibility of Enterobacteriaceae to ciprofloxacin (Cip) paralleled the susceptibility to Nal: decreased susceptibility for Enterobacteriaceae as a whole (96% vs 89%) and E. coli (99% vs 91%). A clear decrease in the level of susceptibility to Cip occurred during the study period among the Nal-resistant strains as demonstrated by the decrease in the median zone diameter (D) observed among the Nal-resistant strains of E. coli (26 mm in 1992 vs 19 mm in 1998-2000). The zone diameter distribution pattern changed from an unimodal distribution in 1992 to a trimodal distribution in 2000 secondary to the occurrence of a population of resistant strains (D = 13 mm) and of a highly resistant population (D = 6 mm). Finally, the susceptibility to Cip of P. aeruginosa strains remained stable around 62% throughout the study period.