Microbiological epidemiology and antibiotic susceptibility of infected meshes after prosthetic abdominal wall repair.

INTRODUCTION: Infectious complications of parietal mesh after prosthetic abdominal wall repair are rare. Their management is complex. Furthermore, the emergence of bacterial resistance, the presence of a foreign material, the need to continue an extended antibiotic therapy, and the choice of an appropriate treatment are crucial. The objective of this study is to access the microbiological epidemiology of infected parietal meshes in order to optimize the empirical antibiotic therapy. METHODS: Between January 2016 and December 2021, a monocentric and retrospective study was performed in patients hospitalized for infected parietal meshes at Avicenne hospital, in Paris area. Clinical and microbiological data such as antibiotic susceptibility were collected. RESULTS: Twenty-six patients with infected parietal meshes have been hospitalized during this period. Meshes were in preaponevrotic positions (n=10; 38%), retromuscular (n=6; 23%) and intraperitoneal (n=10; 38%). Among the 22 (84.6%) documented cases of infections, 17 (77.3%) were polymicrobial. A total of 54 bacteria were isolated, 48 of which had an antibiogram available. The most frequently isolated bacteria were: Enterobacterales (n=19), Enterococcus spp. (n=11) and Staphylococcus aureus (n=6), whereas anaerobes were poorly isolated (n=3). Concerning these isolated bacteria, amoxicillin-clavulanic acid, metronidazole-associated cefotaxime, piperacillin-tazobactam and meropenem were susceptible in 45.5%, 68.2%, 63.6%, 77.2%, of cases, respectively. CONCLUSION: This work highlights that infections of abdominal parietal meshes may be polymicrobial and the association amoxicillin-clavulanic acid cannot be used as a probabilist antibiotic therapy because of the high resistance rate in isolated bacteria. The association piperacillin-tazobactam appears to be a more adapted empirical treatment to preserve carbapenems, a broad-spectrum antibiotic class.

Intra-abdominal abscesses: Microbiological epidemiology and empirical antibiotherapy.

PURPOSE: Data on the microbiological epidemiology of Intra-Abdominal Abscesses (IAAs) are very scarce. We aimed to study the microbiological epidemiology of these infections in order to optimize empirical antibiotic therapy. PATIENTS AND METHODS: Between January 2015 and December 2020, we retrospectively analyzed all IAAs files in our hospital. Clinical and microbiological data such as antibiotic susceptibilities were collected. RESULTS: We studied 243 IAA cases. All in all, 139 (57.2%) IAAs were healthcare-associated and 201 (82.7%) were drained. The highest risk situations for IAAs were appendicitis (n = 69) and diverticulitis (n = 37). Out of the 163 microbiologically documented infections, 136 (81.9%) were polymicrobial. Enterobacterales (n = 192, 36.1%), Enterococcus sp. (n = 84, 17.6%) and anaerobes (n = 66, 16.1%) were the most frequently identified bacteria. Gram-negative bacteria were susceptible to amoxicillin-acid clavulanic, piperacillin-tazobactam, cefotaxime, meropenem in 55.2%, 84.9%, 77.6% and 99.5% of cases, respectively. Concerning Gram-positive bacteria, the susceptibility rate was 81.8% for amoxicillin-clavulanic acid, piperacillin-tazobactam and meropenem, and decreased to 63.4% for cefotaxime. CONCLUSION: This study highlights the polymicrobial profile of IAAs and their low susceptibility to amoxicillin and clavulanic acid. The piperacillin-tazobactam association remained the most appropriate empirical antibiotic therapy.

Revisited distribution of nonfermenting Gram-negative bacilli clinical isolates.

Nonfermenting Gram-negative bacilli (NF-GNB) are ubiquitous environmental opportunistic bacteria frequently misidentified by conventional phenotypic methods. The aim of this study was to determine the distribution of NF-GNB species by 16 S rRNA gene sequencing (used as reference method) and to compare performances of biochemical tests and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). From nine French hospitals, 188 NF-GNB isolates (except P. aeruginosa and A. baumannii) were prospectively collected from 187 clinical samples between December 2008 and May 2009. By using the genotypic approach, 173 (92%) and 188 (100%) isolates were identified to the species and genus level, respectively. They covered 35 species and 20 genera, with a predominance of Stenotrophomonas maltophilia, Achromobacter xylosoxidans, and Pseudomonas putida group bacteria. Of the 173 species-level identified strains, concordant identification to the species-level was obtained for 75.1%, 83% and 88.9% of isolates with API 20 NE strip, the VITEK-2 (ID-GN card) system and MALDI-TOF-MS, respectively. By excluding S. maltophilia isolates accurately identified by the three methods, genus-level identification was much higher for MALDI-TOF-MS (92.9%), compared with API 20 NE and VITEK-2 (76.2% and 80.8%, respectively). In conclusion, MALDI-TOF-MS represents a rapid, inexpensive, and accurate tool for routine identification of NF-GNB in human clinical samples.

Can real-time polymerase chain reaction allow a faster recovery of hospital activity in cases of an incidental discovery of carbapenemase-producing Enterobacteriaceae and vancomycin-resistant Enterococci carriers?

BACKGROUND: Detection of faecal carriers of carbapenemase-producing Enterobacteriaceae (CPE) and vancomycin-resistant Enterococci (VRE) has become a routine medical practice in many countries. In an outbreak setting, several public health organizations recommend three-weekly rectal screenings to rule-out acquisition in contact patients. This strategy, associated with bed closures and reduction of medical activity for a relatively long time, seems costly. AIM: The objective of this study was to test the positive and negative predictive values of reverse transcription polymerase chain reaction (RT-PCR; GeneXpert®) carried-out at Day 0, compared with conventional three-weekly culture-based rectal screenings, in identifying, among contact patients, those who acquired CPE/VRE. METHODS: A multicentre retrospective study was conducted from January2015 to October2018. All contact patients (CPs) were included identified from index patients (IPs) colonized or infected with CPE/VRE, incidentally discovered. Each CP was investigated at Day 0 by PCR (GeneXpert®), and by the recommended three-weekly screenings. FINDINGS: Twenty-two IPs and 159 CPs were included. An average of 0.77 secondary cases per patient was noted, with a mean duration of contact of 10 days (range 1-64). Among the 159 CPs, 16 (10%) had a CPE/VRE-positive culture during the monitoring period. Rectal screenings were positive at Day 0 (10 patients), Day 7 (two patients), Day 14 (four patients). Thirteen of 16 patients with positive culture had a positive PCR at Day 0. Overall, a concordance of 97.5% (155/159) was observed between the three-weekly screenings and Day 0 PCR results. When performed on CPs at Day 0 of the identification of an IP, PCR (GeneXpert®) allowed the reduction in turnaround time by five to 27 days, compared to three-weekly screenings. Positive predictive value and negative predictive value were 100% and 98%, respectively. CONCLUSIONS: The use of RT-PCR (GeneXpert®) can avoid the three-weekly rectal samplings needed to rule-out acquisition of CPE/VRE.

Host and bacterial determinants of initial severity and outcome of Escherichia coli sepsis.

A 1-year prospective cohort study of all episodes of Escherichia coli bacteraemia in two French university hospitals was conducted to assess simultaneously the influence of host and bacterial determinants on the initial severity and outcome of E. coli sepsis. Clinical data (community-acquired/nosocomial infection, immune status, underlying disease, primary source of infection, severity sepsis scoring and outcome), phylogenetic groups (A, B1, D and B2), nine virulence factors (VFs) (papC, papGII, papGIII, sfa/foc, hlyC, cnf1, iucC, fyuA and iroN) and the antibiotic susceptibility of isolates were investigated. All VFs except iucC were significantly more prevalent (p <0.05) among the B2 group isolates. The non-B2 isolates were more frequently resistant to antibiotics than were B2 isolates (p <0.05). There were significantly more B2 isolates from immunocompetent than from immunocompromised patients (p <0.05). No bacterial or host determinants influenced the initial severity of sepsis. Multivariate analysis revealed that the presence of papGIII, septic shock at baseline and a non-urinary tract origin of sepsis were associated independently with a fatal outcome (p 0.04, <0.0001 and 0.04, respectively). A factorial analysis of correspondence allowed two populations of isolates to be distinguished: those belonging to the B2 group were associated more frequently with susceptibility to antibiotics, community-acquired infection, a urinary tract origin and immunocompetent hosts; those belonging to the A, B1 or D groups were associated more frequently with resistance to antibiotics, a nosocomial origin, a non-urinary tract source and immunocompromised hosts. Although no influence of host or bacterial determinants on the initial severity of sepsis was detected, bacterial and host determinants both influenced the outcome of E. coli sepsis significantly.

Escherichia coli native valve endocarditis.

Among 36 cases of Escherichia coli native valve endocarditis (NVE) that met Duke criteria (31 cases in the literature between 1909 and 2002, and five cases seen in Paris, France), the urinary tract was the most common portal of entry. The majority (72.2%) of cases developed in elderly females. Overall, the proportion of patients aged > 70 years rose from 5.3% in 1982 to 22.9% in 2002. Persistent E. coli bacteraemia in the elderly in the absence of cardiac risk-factors may be a sign of NVE and should prompt an investigation by echocardiography.

MALDI-TOF MS contribution to diagnosis of melioidosis in a nonendemic country in three French travellers.

Melioidosis is an endemic disease in Southeast Asia and northern Australia. An increasing number of cases are being reported in nonendemic countries, making the diagnosis less obvious. We discuss the identification of Burkholderia pseudomallei using matrix-assisted desorption ionization-time of flight mass spectrometry on the occasion of recent cases of imported melioidosis in French travellers.

[Risk factors and screening strategy for group B streptococcal colonization in pregnant women: results of a prospective study]. / Facteurs de risque et stratégie de dépistage de la colonisation par le streptocoque du groupe B chez la femme enceinte: résultats d'une étude prospective.

OBJECTIVES: Group B Streptococcus (GBS) continues to be the most important bacterial cause of sepsis, meningitidis in newborns. American consensus guidelines have been published. They recommended the use of either risk-based strategy or screening-based approach for GBS colonization in pregnant women to identify candidates for intrapartum prophylaxis. Screening consists of obtaining vaginal and anorectal specimens for culture at 35 to 37 weeks' gestation. The aim of this prospective study was to assess the usefulness of systematic and concomitant GBS screening by rectal and vaginal swab in pregnant women. A questionnaire designed to determine the risk factors for colonization by GBS was completed. MATERIALS AND METHODS: We have screened 370 pregnant women with rectal and vaginal swab. RESULTS: Fifty seven (15.4%) women had positive GBS cultures. Of those women, the rectum and the vagina were the only site of colonization in 16 (4.3%) and 8 (2.2%) women respectively. None of the factors studied was significantly associated with GBS colonization. CONCLUSION: Detection of GBS is enhanced by 40% by using vaginal and anorectal swabs compared to a vaginal swab alone. No studied factor appeared to predict GBS colonization, which incited us to screen all pregnant women.

Gram-negative bacteremia: which empirical antibiotic therapy?

PURPOSE: Given the increasing frequency of cefotaxime-resistant strains, third-generation cephalosporins (3GC e.g. cefotaxime, ceftriaxone) might not be recommended any longer as empirical antibiotic therapy for community-acquired Gram-negative bacteremia (CA-GNB). PATIENTS AND METHODS: We conducted a multicenter prospective descriptive study including patients with CA-GNB. RESULTS: Two hundred and nineteen patients were included. Escherichia coli and Pseudomonas aeruginosa were the most frequently isolated species in 63% (n=138) and 11% (n=24) of the cases, respectively. The prevalence of cefotaxime-resistance reached 18% (n=39) mostly due to intrinsic resistance (27 cases, 12%). The presence of invasive material (P<0.001), the origin of the patient (Paris region or West of France) (P=0.006), and home health care (P<0.001) were variables predicting resistant GNB. The negative predictive value for resistance in patients with invasive material coming from the West of France, or without invasive material and with home health care was 94%. The positive predictive value for patients with invasive material living in Paris, or without invasive material and with home health care only reached 58 and 54%, respectively. CONCLUSIONS: Using 3GC for CA-GNB due to cefotaxime-resistant strains was relatively frequent, ESBL-producing Enterobacteriaceae being rarely involved. Our study highlights the role of local epidemiology; before any changes to first-line antibiotic therapy, local epidemiological data should be taken into account.

Management of mycetomas in France.

OBJECTIVE OF THE STUDY: Mycetomas are chronic sub-cutaneous tropical infections in which exogenous causative agents, fungal (eumycetes) or bacterial (actinomycetes), generate grains. The typical presentation is multi-fistulized pseudotumors. This disease, particularly eumycetoma, is difficult to treat. It is a major health problem in tropical and subtropical countries. In France, the disease is rare, but patients have access to a broader range of treatments. The authors had for objective to present the cases of mycetomas diagnosed in developed country and their management. PATIENTS AND METHODS: A retrospective study was made on the clinical presentation and management of mycetomas from 1995 to 2011, in the Bobigny Avicenne teaching hospital. RESULTS: Six patient files were studied. The patients were men with a median age of 31 years (16-70). Five patients were from Sub Saharan Africa, one from Sri Lanka. The etiologies were one actinomycetoma and five eumycetomas. There was bone involvement in five cases. There was one atypical presentation: a primary intra-osseous mycetoma. Three patients were cured including two by surgical management and one by medical treatment (actinomycetoma). Antifungal therapy failed (four patients) in every case (voriconazole, itraconazole, ketoconazole, terbinafine, caspofungin). CONCLUSION: The results of this study made in a non-epidemic zone revealed that despite a typical clinical presentation, the diagnosis and management were delayed because this imported disease is rare in France. The patients received new broad-spectrum triazole and caspofungin, but none were cured with antifungal therapy alone.

Severity of Escherichia coli bacteraemia is independent of the intrinsic virulence of the strains assessed in a mouse model.

Extraintestinal pathogenic Escherichia coli (ExPEC) strains, a major cause of bacteraemia, typically belong to phylogenetic group B2 and express diverse accessory traits that contribute to virulence in mouse infection models. However, their high genomic diversity obscures the relationship between virulence factors and severity of infection in patients. In this study, we analysed concomitantly the strain's expression of virulence in a mouse model, genomic determinants and the clinical severity of infection in 60 bacteraemic patients. We show that bacterial virulence based on an animal model study and virulence factor determination is not correlated with pejorative outcome of E. coli human blood infections.

[Prescriptions of glycopeptides in 10 university hospitals in Paris area: a 1-day survey]. / Prescriptions de glycopeptides dans dix centres hospitaliers d'Île-de-France: enquête un jour donné.

PURPOSE: The prescription of glycopeptides (GP) was evaluated in hospitalized patients. METHODS: A 1-day survey was performed in 10 hospitals of the Île-de-France region regarding the prescription of GP. Characteristics of the included patients, indications of prescription and modalities of GP administration were studied independently of the prescribers. RESULTS: Overall, 90 patients (median age of 49 years [10 days-89 years]) were treated with a GP (vancomycin: 76; teicoplanin: 14). Indications of therapy included a microbiologically documented infection in 40 cases (44%), an empiric therapy in 44 cases (49%) and a prophylaxis in six cases (7%). In documented infections, main isolated pathogens were: coagulase-negative staphylococci (49%) and Staphylococcus aureus (32%) that were susceptible to methicilline in 27 and 26%, respectively. Vancomycin was administered intravenously (IV) in 71 cases (intermittent dosing in 41 patients (58%) and continuous infusion in 30 patients (42%), as central venous catheter lock in four patients and per os in one patient. In continuously infusion regimens, a loading dose at the initiation of treatment had been administered in 19 cases (63%). The median dosage the first day of curative treatment was <20mg/kg in 10 patients (20% of patients had normal renal function). Teicoplanin (median dosage: 8mg/kg, [3-13]) was IV infused in 86% of cases. Monitoring of serum GP concentrations was performed in only 58% of the cases (vancomycin: 47; teicoplanin: five). A low trough serum concentration was observed in 54% of the 52 monitored patients. The dosage of GP was readapted in only 55% of such cases. CONCLUSION: In this 1-day survey, we observed that GP administration was not optimal. Indeed, prolonged prescription of GP as empiric therapy was frequent, monitoring was not systematic, and prescribed dosages were often inadequate.

Mycobacterium heckeshornense: an emerging pathogen responsible for a recurrent lung infection.

Mycobacterium heckeshornense was responsible for a severe, recurrent and chronic pulmonary infection in an immunocompetent 65-year-old woman. The pathogen, initially identified as Mycobacterium xenopi and considered as a contaminant, led to a delayed adapted antimicrobial treatment. Although M. heckeshornense is phenotypically closely related to M. xenopi, its pathogenicity is noticeably higher. Accurate molecular diagnosis methods and treatment guidelines are needed to improve the management of patients infected by this uncommon pathogen.

Serratia marcescens prosthesis infection successfully treated with meropenem after imipenem failure.

A 78-year-old woman developed an early knee-prosthesis infection due to multiresistant Serratia marcescens that was successfully treated with high-dose meropenem, after failure of a long-term therapy combining imipenem and multiple surgical interventions. Because of its lower neurotoxicity, meropenem might be preferred to imipenem/cilastatin for the treatment of osteo-articular infections due to multiresistant Gram-negative bacilli in the elderly.

Low seroprevalence and poor specificity of antineutrophil cytoplasmic antibodies in tuberculosis.

OBJECTIVES: Recently published findings suggested that antineutrophil cytoplasmic antibodies (ANCA), particularly those with a cytoplasmic (C-ANCA) labelling pattern and targeting proteinase 3 (anti-PR3), might be markers of tuberculosis (TB). This is a critical issue, because C-ANCA/anti-PR3 were considered to be a highly specific hallmark of Wegener's granulomatosis or microscopic polyangiitis and because TB may clinically mimic Wegener's granulomatosis. We therefore undertook a study with the aim of investigating further the prevalence and specificity of ANCA in TB. METHODS: We evaluated serum samples from 67 patients diagnosed with culture-proven TB and 10 previously untested control samples from patients known to be ANCA positive (four Wegener's granulomatosis and two microscopic polyangiitides) or negative. All 77 sera were screened for ANCA using commercially available indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) for anti-PR3 and antimyeloperoxidase (MPO). IIF-positive and anti-PR3- and anti-MPO-negative sera were also tested for bactericidal/permeability-increasing protein, lactoferrin, elastase and cathepsin G specificities with commercially available ELISA. RESULTS: IIF detected ANCA in seven (10%) of the TB sera, including three C-ANCA and four atypical perinuclear-labelling ANCA. Only one IIF-negative specimen was anti-PR3 positive in ELISA. ANCA testing of the control sera yielded IIF and ELISA results concordant with previous findings, except for one borderline ELISA. CONCLUSION: Our results indicate that TB is associated with low ANCA seroprevalence and poor specificity, with no test serum showing combined C-ANCA/anti-PR3 activity. In a clinical setting of Wegener's granulomatosis/TB mimicry, such combined reactivity would seem to be more suggestive of Wegener's granulomatosis.

[Epidemiological survey of a suspected nosocomial case of tuberculosis by spoligotyping]. / Place du spoligotypage lors d'une enquête épidémiologique devant un cas de suspicion de tuberculose pulmonaire nosocomiale.

Transmission of tuberculosis within hospitals has been increasingly recognized as a hazard for patients and health care workers. A case of pulmonary tuberculosis was detected in September 2003 in a nursing auxiliary working at Avicenne's Hospital. This 49 year-old woman was considered infected since April 2003. During this 6 months period, she worked in 23 distinct hospital units and could have contaminated patients and hospital staffs. The epidemiological survey was comprised for 1735 individuals (701 hospital staffs and 1034 patients). It encompassed clinical, para-clinical investigations and bacteriological investigations. Furthermore, between January 2003 and September 2004, a systematic comparison of 62 Mycobacterium tuberculosis strains isolated in the hospital was conducted by spoligotyping, a molecular typing method in order to access an eventual transmission. The nursing auxiliary's strain clearly showed a distinct spoligotype from the other investigated strains. This spoligotype was unique in the international spoligotype database. In this large epidemiological survey of a case of suspected nosocomial of tuberculosis, spoligotyping appeared as an interesting, easy and rapid method of molecular typing. It allowed to demonstrate that the nursing auxiliary tuberculosis case was unrelated to the others cases of tuberculosis diagnosed in the hospital during this period.