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.

Exogenous acquisition of Pseudomonas aeruginosa in intensive care units: a prospective multi-centre study (DYNAPYO study).

BACKGROUND: Pseudomonas aeruginosa remains one of the most common nosocomial pathogens in intensive care units (ICUs). Although exogenous acquisition has been widely documented in outbreaks, its importance is unclear in non-epidemic situations. AIM: To elucidate the role of exogenous origin of P. aeruginosa in ICU patients. METHODS: A chronological analysis of the acquisition of P. aeruginosa was performed using samples collected in 2009 in the DYNAPYO cohort study, during which patients and tap water were screened weekly. Molecular relatedness of P. aeruginosa isolates was investigated by pulsed-field gel electrophoresis. Exogenous acquisition was defined as identification of a P. aeruginosa pulsotype previously isolated from another patient or tap water in the ICU. FINDINGS: The DYNAPYO cohort included 1808 patients (10,402 samples) and 233 water taps (4946 samples). Typing of 1515 isolates from 373 patients and 375 isolates from 81 tap water samples identified 296 pulsotypes. Analysis showed exogenous acquisition in 170 (45.6%) of 373 patients. The pulsotype identified had previously been isolated from another patient and from a tap water sample for 86 and 29 patients, respectively. The results differed according to the ICU. CONCLUSION: Exogenous acquisition of P. aeruginosa could be prevented in half of patients. The overall findings of this survey support the need for studies on routes of transmission and risk assessment approach to better define how to control exogenous acquisition in ICUs.

Prospective study on antimicrobial resistance in leprosy cases diagnosed in France from 2001 to 2015.

Antimicrobial resistance (AMR) in leprosy is mostly unknown because Mycobacterium leprae does not grow in vitro and bacteriologic investigations have been abandoned. However, molecular detection of resistance can be applied to multibacillary cases. Patients living in France mainland or in the French territories and diagnosed with leprosy from 2001 to 2015 were prospectively studied for AMR by detecting mutations in rpoB for rifampicin resistance, in folP1 for dapsone and in gyrA for ofloxacin. Single nucleotide polymorphism (SNP) genotypes 1-4 were determined for resistant strains. Of 334 skin biopsy samples received for suspicion of leprosy, 184 (55.1%) were positive for M. leprae (acid-fast bacilli and M. leprae-specific repetitive element PCR) corresponding to 160 multibacillary cases. AMR was detected in 18 cases (11.3%): 13 cases (8.1%) of dapsone resistance, three (1.9%) rifampicin and two (1.3%) ofloxacin. There were no strains with multidrug resistance. The mutations (numbering system of M. leprae TN strain genome) found were P55L (n = 7), T53I (n = 5), T53A (n = 1) in folP1; S456L (n = 2) and S456F (n = 1) in rpoB; and A91V (n = 2) in gyrA. Resistance proportion differ significantly between new and relapse cases (9/127, 7.0%, vs. 9/33, 25.7%, p 0.003). The frequency distribution of SNP1-4 types of resistant strains was two, one, 12 and three with five SNP3 cases from New Caledonia harbouring the same T53I FolP1 substitution. This is the first report of AMR surveillance for new and relapse cases of leprosy in Europe. Detection of resistance helped in individual treatment as well as in epidemiologic investigations.

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.

Comparison of methods available for identification of Mycobacterium chimaera.

OBJECTIVES: Mycobacterium chimaera is a recently described nontuberculous mycobacterium belonging to the Mycobacterium avium complex (MAC). Because this species is implicated in a worldwide outbreak due to contaminated heater-cooler unit water tanks during open-heart surgery, it has become mandatory for clinical microbiology laboratories to be able to differentiate M. chimaera from the other MAC species, especially M. intracellulare. Such identification has so far been restricted to specialized laboratories because it required the analysis of several gene sequences. The aim of this study was to evaluate commercial methods for identifying M. chimaera with regard to the reference gene sequencing ITS, the internal transcribed spacer 16-23S. METHODS: Forty-seven clinical and environmental isolates including 41 MAC were identified by (a) PCR sequencing of the ITS and hsp65 genes, (b) three molecular biology kits (INNO-LiPA Mycobacteria, GenoType Mycobacterium CM and GenoType NTM-DR) and (c) matrix-assisted desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) using Microflex LT. RESULTS: There was a high concordance for species determination between the reference ITS sequencing and the GenoType NTM-DR test (39/41, 95%), the INNO-LiPA Mycobacteria test (38/41, 93%) and the hsp65 sequencing (38/41, 93%). The GenoType Mycobacterium CM test did not distinguish M. chimaera from M. intracellulare. MALDI-TOF MS distinguished two M. chimaera-M. intracellulare groups separated from M. avium and from the other mycobacterial species on a score-oriented dendrogram, but it also failed to differentiate the two species. CONCLUSIONS: INNO-LiPA Mycobacteria and GenoType NTM-DR are efficient assays for M. chimaera identification in clinical microbiology laboratories.

Update on the epidemiology, diagnosis, and treatment of leprosy.

Leprosy is an infectious disease that has now been reported for more than 2000 years. The leprosy elimination goal set by the World Health Organization (WHO), i.e. a global prevalence rate <1 patient per 10,000 population, was achieved in the year 2000, but more than 200,000 new case patients are still reported each year, particularly in India, Brazil, and Indonesia. Leprosy is a specific infection: (i) it is a chronic infection primarily affecting the skin and peripheral nerves, (ii) Mycobacterium leprae is one of the last bacterial species of medical interest that cannot be cultured in vitro (mainly because of its reductive genome evolution), and (iii) transmission and pathophysiological data is still limited. The various presentations of the disease (Ridley-Jopling and WHO classifications) are correlated with the patient's immune response, bacillary load, and by the delay before diagnosis. Multidrug therapy (dapsone, rifampicin, with or without clofazimine) has been recommended since 1982 as the standard treatment of leprosy; 6 months for patients presenting with paucibacillary leprosy and 12 months for patients presenting with multibacillary leprosy. The worldwide use of leprosy drugs started in the 1980s and their free access since 1995 contributed to the drastic decline in the number of new case patients. Resistant strains are however emerging despite the use of multidrug therapy; identifying and monitoring resistance is still necessary.

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).

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 ß-lactam/ß-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 ß-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, ß-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 ß-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 ß-lactamase enzymes is easily driven by antibiotic pressure, even during a short antibiotic therapy.

Diagnostic criteria for urinary tract infection in hospitalized elderly patients over 75 years of age: a multicenter cross-sectional study.

INTRODUCTION: Urinary tract infection (UTI) is one of the most frequent infections in geriatric patients. Nevertheless, the diagnosis remains difficult because of the high prevalence of asymptomatic bacteriuria (AB). We studied the diagnosis criteria used by physicians in geriatric patients 75 years of age or more. METHOD: A multicenter study was carried out in October 2009 in acute care wards (geriatrics, infectious diseases, internal medicine). During 1 week, the local investigator collected all positive urine microscopy and culture in geriatric patients 75 years of age or more and filled out a questionnaire on the final diagnosis (AB, cystitis, pyelonephritis, prostatitis), symptoms, clinical signs, and other infectious diagnosis. RESULTS: Two hundred and forty-one questionnaires were filled out in 48 wards. Physicians diagnosed AB in 91 patients (37.8%), cystitis in 72 (29.9%), pyelonephritis in 48 (19.9%), prostatitis in 20 (8.3%). 28.2% of patients were asymptomatic; 35% presented with clinical signs. General signs were significantly associated with invasive infection and the absence of functional signs with AB. Among the patients presenting with an invasive UTI, 27.9% also presented with another infection. This other infection was not statistically associated with AB, cystitis, or invasive UTI. CONCLUSION: Too many urine microscopy and culture procedures are not justified, and too many patients are diagnosed with several infections. Usual functional and clinical signs are important for the diagnosis but are infrequent. It seems necessary to review the range of clinical presentations and diagnostic criteria for UTI in geriatric patients.

[Histopathological study of Mycobacterium marinum infection]. / Aspects histopathologiques de l'infection à Mycobacterium marinum.

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.

Evaluation of the new MB redox system for detection of growth of mycobacteria.

We evaluated a new mycobacterial culture system, MB Redox, for recovery rate and time to detection of mycobacteria from 742 consecutive respiratory specimens and compared the results to those found with Löwenstein-Jensen (LJ) medium. Twenty specimens (2.7%) were positive for M. tuberculosis: 17 on LJ medium and 19 in MB Redox, with 16 specimens positive in both media. In addition, 24 specimens (3.2%) were positive for nontuberculous mycobacteria (NTM), 20 on LJ medium, 18 in MB Redox, and 14 in both media. For M. tuberculosis, the mean times to detection were 28.9 days on LJ medium and 23.6 days in MB Redox, and for NTM, the mean times to detection were 40.6 days on LJ medium and 32.3 days in MB Redox.

Clinical utility of an amplification test based on ligase chain reaction in pulmonary tuberculosis.

We evaluated the sensitivity and specificity of a new semiautomated direct amplification test (DAT), the LCx-MTB, for the diagnosis of pulmonary tuberculosis (TB) and assessed its positive predictive value by focusing on patients with high clinical and radiologic suspicion of pulmonary TB. Respiratory tract specimens from 32 consecutive patients with high suspicion of active pulmonary TB (case patients) and from 204 control patients were cultured for Mycobacterium tuberculosis and tested by LCx-MTB. Sensitivity and specificity of LCx-MTB when compared with culture was, respectively, 80 and 98%. Pulmonary TB was confirmed in the 32 case patients without knowledge of the LCx results: 18 patients were smear- and culture-positive for M. tuberculosis, and all gave at least one specimen that was LCx-positive. Eight patients were smear-negative culture-positive, and seven gave at least one LCx-positive specimen. LCx-MTB was negative in all the specimens obtained from six patients with smear- and culture-negative TB. A positive LCx-MTB result in a smear negative specimen was 100% predictive that at least one of the case patients' specimens would yield M. tuberculosis. As a consequence, knowledge of the LCx-MTB results at the time of specimen collection could have hastened the start of the antituberculosis therapy in three (21%) smear-negative case patients and could have avoided unnecessary invasive diagnostic procedures in four (29%). We conclude that the sensitivity of LCx-MTB in detecting M. tuberculosis DNA in respiratory tract specimens is similar to other DATs, that LCx-MTB is a reliable test for confirmation of TB in smear-positive patients and that LCx-MTB could be beneficial as a diagnostic step in smear-negative patients with a high suspicion of pulmonary TB.