Emergence of NDM-1- and IMP-14a-producing Enterobacteriaceae in Thailand.

OBJECTIVES: To detect carbapenemases in clinical isolates of Enterobacteriaceae collected from patients in a university hospital in Thailand between October 2010 and August 2011. METHODS: A total of 4818 Enterobacteriaceae isolates were screened for the presence of carbapenemases by ertapenem and imipenem disc diffusion tests. All positive screening isolates were subjected to modified Hodge test, phenylboronic acid- and EDTA-carbapenem combined disc tests and two multiplex PCRs of bla(IMP), bla(VIM), bla(SPM), bla(SIM) and bla(GIM), and of bla(KPC), bla(NDM) and bla(OXA-48). Carbapenemase-producing isolates were typed by PFGE and then characterized by antimicrobial susceptibility tests. Conjugation was performed using a broth culture mating method. RESULTS: Two isolates each of Escherichia coli, Klebsiella pneumoniae and Citrobacter freundii produced NDM-1, whereas two other isolates of K. pneumoniae produced IMP-14a. DNA fingerprints revealed that the metallo-ß-lactamase (MBL)-producing isolates were of different strains except for clonal strains of C. freundii. In vitro transfer of carbapenem resistance was successful for the eight MBL-producing isolates. All MBL producers were susceptible to colistin and tigecycline. The six NDM-producing isolates were recovered from the urine of three patients, who had no history of travel outside Thailand. Interestingly, one patient had chronic urinary tract infections caused by a K. pneumoniae strain and two strains of E. coli producing NDM-1. CONCLUSIONS: Surveillance of carbapenemases, particularly NDM-1, in Enterobacteriaceae is urgently needed to control and prevent the spread of these resistance determinants in our country.

Prior Carriage Predicts Intensive Care Unit Infections Caused by Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae.

Intensive care unit-acquired infection (ICU-AI) and extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) carriage are a major concern worldwide. Our objective was to investigate the impact of ESBL-PE carriage on ICU-AI. Our study was prospective, observational, and noninterventional. It was conducted over a 5-year period (Jan 2013-Dec 2017) in the medical-surgical intensive care unit of the Cayenne General Hospital (French Amazonia). During the study period, 1,340 patients were included, 271 (20.2%) developed ICU-AI, and 16.2% of these were caused by ESBL-PE. The main sites of ICU-AI were ventilator-associated pneumonia (35.8%) and primary bloodstream infection (29.8%). The main responsible microorganisms were Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae (ESBL-P in 35.8% of isolates), and Enterobacter cloacae (ESBL-P in 29.8% of isolates). Prior ESBL-PE carriage was diagnosed in 27.6% of patients with ICU-AI. In multivariable analysis, the sole factor associated with ESBL-PE as the responsible organism of ICU-AI was ESBL-PE carriage before ICU-AI (P < 0.001; odds ratio: 7.9 95% CI: 3.4-18.9). ESBL-PE carriers (74 patients) developed ICU-AI which was caused by ESBL-PE in 32 cases (43.2%). This proportion of patients carrying ESBL-PE who developed ICU-AI to the same microorganism was 51.2% in ESBL-P K. pneumoniae, 5.6% in ESBL-P Escherichia coli, and 40% in ESBL-P Enterobacter spp. NPV of ESBL-PE carriage to predict ICU-AI caused by ESBL-PE was above 94% and PPV was above 43%. Carriage of ESBL-P K pneumoniae and Enterobacter spp. is a strong predictor of ICU-AI caused by these two microorganisms.

Comparison of disease severity scoring systems for dairy cattle with acute coliform mastitis.

OBJECTIVE: To compare use of 4 disease severity scoring systems to predict bacteremia (yes vs no) and outcome (survived vs died or culled) in dairy cows with acute coliform mastitis (ACM). DESIGN: Retrospective cohort study. ANIMALS: 99 dairy cows with ACM. PROCEDURES: Cows were classified as having mild, moderate, or severe disease with a scoring system based on systemic disease signs alone (systemic severity score [SSS] system), a system based on local disease signs alone (local severity score [LSS] system), and 2 previously described systems based on a combination of local and systemic signs (local-systemic score 1 [LS1] and local-systemic score 2 [LS2] systems). Test performance was calculated to determine whether a severe disease classification could be used to predict bacteremia or outcome. RESULTS: 21%, 53%, 63%, and 38% of cows were classified as having severe disease with the SSS, LSS, LS1, and LS2 systems, respectively. For both bacteremia and outcome, sensitivity was highest for the LS1 system, but specificity and accuracy were highest for the SSS system. Examination of a scatterplot of true-positive rate versus false-positive rate for each of the scoring systems indicated that the SSS and LS2 systems were similar in their ability to correctly identify cows with bacteremia or an adverse outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the SSS scoring system was better for identifying cows with bacteremia or an adverse outcome than was the LSS system and that the LS1 and LS2 systems were intermediate in their discriminatory abilities.

[Prevalence of ESBL strains in urinary tract infections in children in 1996 and 2004]. / Wystepowanie szczepów ESBL w zakazeniach ukladu moczowego u dzieci w latach 1996 i 2004.

Ethiological agents in urinary tract infections and prevalence of bacterial strains producing extended spectrum of beta-lactamases isolated from urine of children with urinary tract infections were compared. Patients were hospitalized in Department of Pediatry, Pediatric Gastroenterology and Oncology of Medical University of Gdansk in 1996 and 2004. Seventy bacterial strains isolated from urine in 1996 and 113 strains isolated in 2004 were analyzed. In both years Enterobacteriaceae were the most frequently encountered with Escherichia coli predominance. Proteus spp. (10.9%), Enterobacter spp. (7.1%), Klebsiella spp. (4.4%), and Enterococcus spp. (9.3%) were isolated rarely. Among bacteria isolated in 1996 there were no ESBL strains while in 2004 ESBL strains accounted for 11.5% of all urinary bacteria. Klebsiella oxytoca (25%) and Klebsiella pneumaniae (20%) produced ESBL most frequently. ESBL production was less frequent in Escherichia coli (13.2%) and Proteus mirablilis (10%). In conclusion, among bacteria isolated from urine of children with urinary tract infections G(-) strains producing ESBL were encountered only in recent years.

Risk factors for infection and molecular typing in patients in the intensive care unit colonized with nosocomial Enterobacter aerogenes.

OBJECTIVES: To determine the frequency of colonization by Enterobacter aerogenes in patients in the intensive care unit (ICU) for more than 48 hours and to evaluate the risk factors for infection in patients colonized by this bacteria. DESIGN: An 8-month prospective study. SETTING: A 12-bed medical-surgical ICU in a 450-bed, university-affiliated, tertiary-care hospital in Belgium. METHOD: Pulsed-field gel electrophoresis was used to determine the genotypes of E. aerogenes isolates. RESULTS: We observed two major clones of E. aerogenes in the ICU. Interestingly, 87.5% of infected patients had the same genomic profile for colonization and infection. Risk factors for infection in this particular population included younger age, prolonged hospital stay, mechanical ventilation, and bronchoscopy. CONCLUSIONS: Colonization is a major prerequisite for infection. The identification of risk factors for infection in colonized patients can optimize the quality of treatment in the ICU.

Use of systemic disease signs to assess disease severity in dairy cows with acute coliform mastitis.

OBJECTIVE: To evaluate the use of systemic disease signs for classifying severity of acute coliform mastitis in dairy cows. DESIGN: Prospective cohort study. ANIMALS: 144 dairy cows. PROCEDURE: Cows were examined at the time of initial identification of disease (time 0) and classified as having mild, moderate, or severe disease on the basis of rectal temperature, hydration status, rumen contraction rate, and attitude. A CBC and serum biochemical analyses were performed, and milk samples were submitted for bacterial culture at time 0 and 48 hours later. RESULTS: 69 cows were classified as having mild disease, 44 as having moderate disease, and 31 as having severe disease. Median WBC and neutrophil counts were significantly lower in cows with moderate or severe disease at time 0 than in cows with mild disease. Band neutrophil count was significantly higher at 48 hours and serum calcium concentration was significantly lower at time 0 and at 48 hours in cows with severe or moderate disease, compared with cows with mild disease. Twenty-eight, 51, and 77% of cows with mild, moderate, and severe disease, respectively, had > 100,000 colony-forming units/ml of milk at time 0. The odds that a cow with severe disease would die or be culled were 3.6 times the odds for a cow with moderate disease and 11.2 times the odds for a cow with mild disease. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a classification scheme based on readily observable systemic disease signs can be used to classify disease severity in cows with acute coliform mastitis.

In vivo multiclonal transfer of bla(KPC-3) from Klebsiella pneumoniae to Escherichia coli in surgery patients.

During active surveillance at the Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT, Palermo, Italy) with the CARBA screening medium, five pairs of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae and Escherichia coli strains were isolated in each of five colonized patients. In each patient, lateral gene transfer was demonstrated by comparing K. pneumoniae and E. coli strains, both possessing KPC-3, Tn4401a and pKpQIL-IT elements. The isolates were found to be multiclonal by multilocus sequence typing (sequence type (ST) 512 related to ST258, and ST307 belonging to a clonal complex different from the habitual sequence clone ST258 isolated in Italy) and pulsed-field gel electrophoresis. The results of our study highlight the easy transfer of KPC among Enterobacteriaceae colonizing the human intestine, and the active and careful surveillance required to identify and prevent the spread of these multidrug-resistant microorganisms.

[Why should antibiotic therapy be avoided in case of acute infectious diarrhea?]. / Pourquoi faut-il éviter l'antibiothérapie dans la diarrhée aiguë présumée infectieuse ?

Antibiotic prescription for acute diarrhea is not devoid of risks. There are individual risks for the patient, such as allergy, gastrointestinal side effects, Clostridium difficile infection. There is also a risk of selection of antibiotic resistance in the digestive microbiota, leading to the emergence of multiresistant isolates such as extended-spectrum ß-lactamase or carbapenemase producing Enterobacteriaceae, which are able to disseminate worldwide. Antibiotic prescriptions may thus be limited to patients with entero-invasive or severe choleriform diarrhea.

Utility of the VITEK 2 Advanced Expert System for identification of extended-spectrum beta-lactamase production in Enterobacter spp.

Forty clinical isolates of Enterobacter spp. were identified as extended-spectrum beta-lactamase (ESBL) producers by disk diffusion. The VITEK 2 Advanced Expert System (AES) identified the ESBL phenotype in only 25 isolates (62.5%), and erroneously reported cephalosporin susceptibility in 11 isolates (28%). Refinements in the AES are required in order to improve ESBL detection in Enterobacter.

Bowel infection predisposing to reactive arthritis.

Postenteric reactive arthritis is one of several syndromes in which arthritis appears to be secondary to gastrointestinal tract pathology. A wide range of microbes may trigger this type of arthritis. On the other hand, there are differences between strains in their arthritogenic potential. Two possible mechanisms, not mutually exclusive, can be forwarded to explain these findings: first, particular characteristics of the infective organisms are necessary to initiate events leading to reactive arthritis and, second, particular anatomical locations and a certain degree of mucosal involvement are needed to initiate the process. Studies on humoral and cellular immune responses have not revealed any unifying feature that could explain the pathogenesis of reactive arthritis. The HLA allele B27 plays some kind of key role. Yet the elucidation of the fine structure of B27 specificity has not led to any immediate breakthrough in the understanding of the pathogenetic pathways. Experience of reactive arthritis associated with acquired immunodeficiency syndrome suggests that helper T cells are not involved. Antigen persistence may be connected with continuation of the inflammation. Recent developments in the serology of enteric bacterial infections will provide additional tools for uncovering the triggering agents in reactive arthritis. 'Idiopathic reactive arthritis' associated with clinically silent terminal ileitis is an interesting disease entity requiring further characterization.

Most Enterobacter aerogenes strains in France belong to a prevalent clone.

The aim of this study was to determine the distribution in France of the Enterobacter aerogenes prevalent clone isolated in the hospitals of the Marseille area (A. Davin-Regli, D. Monnet, P. Saux, C. Bosi, R. Charrel, A. Barthelemy, and C. Bollet, J. Clin. Microbiol. 34:1474-1480, 1996). A total of 123 E. aerogenes isolates were collected from 23 hospital laboratories and analyzed by random amplification of polymorphic DNA and enterobacterial repetitive intergenic consensus-PCR to determine their epidemiological relatedness. Molecular typing revealed that 21 of the 23 laboratories had isolated this prevalent clone harboring the plasmid encoding for extended-spectrum beta-lactamase of the TEM-24 type. Most isolates were susceptible only to imipenem and gentamicin. Their dissemination seems to be clonal and was probably the result of the general use of broad-spectrum cephalosporins and quinolones. Four isolates showed an alteration of their outer membrane proteins, causing decrease of susceptibility to third-generation cephalosporins and imipenem and leading to the critical situation of having no alternative therapeutic. The large dissemination of the E. aerogenes prevalent clone probably results from its good adaptation to the antibiotics administered in France and the hospital environment, particularly in intensive care units.

Detection of extended-spectrum beta-lactamases in clinical isolates of Enterobacter cloacae and Enterobacter aerogenes.

The aim of the present study was to investigate the frequency of extended-spectrum beta-lactamases (ESBLs) in a consecutive collection of clinical isolates of Enterobacter spp. The abilities of various screening methods to detect ESBLs in enterobacters were simultaneously tested. Among the 68 consecutive isolates (56 Enterobacter cloacae and 12 Enterobacter aerogenes isolates) that were analyzed for beta-lactamase content, 21 (25 and 58%, respectively) possessed transferable ESBLs with pIs of 8.2 and phenotypic characteristics of SHV-type enzymes, 8 (14.3%) of the E. cloacae isolates produced a previously nondescribed, clavulanate-susceptible ESBL that exhibited a pI of 6.9 and that conferred a ceftazidime resistance phenotype on Escherichia coli transconjugants, and 2 E. cloacae isolates produced both of these enzymes. Among the total of 31 isolates that were considered ESBL producers, the Vitek ESBL detection test was positive for 2 (6.5%) strains, and the conventional double-disk synergy test (DDST) with amoxicillin-clavulanate and with expanded-spectrum cephalosporins and aztreonam was positive for 5 (16%) strains. Modifications of the DDST consisting of closer application of the disks (at 20 instead of 30 mm), the use of cefepime, and the use of both modifications increased the sensitivity of this test to 71, 61, and 90%, respectively. Of the 37 isolates for which isoelectric focusing failed to determine ESBLs, the Vitek test was false positive for 1 isolate and the various forms of DDSTs were false-positive for 3 isolates.

Vigilancia de infecciones nosocomiales / Vigilance of nosocomial infections

Se revisaron 3340 infecciones intrahospitalarias (IIH), ocurridas durante 18 años (1976 a 1993), apoyados en la definición y criterios operacionales para su clasificación recomendados por los CDC, Centers for Disease Control de Atlanta, Estados Unidos de América del Norte. Las principales infecciones identificadas en orden de frecuencia fueron: en las vías urinarias, flebitis, neumonías, tejidos blandos, exantemas y heridas quirúrgicas. Predominaron los microorganismos gramnegativos con una conversión en los últimos años de los cocos grampositivos y levaduras. La tasa de mortalidad asociada a IIH fue de 17.5 por ciento, mayor a la informada por los institutos nacionales de salud de 14 por ciento. La IIH en nuestro estudio están relacionadas con procedimientos invasivos como catéteres vesicales e intravenosos y asistencia ventilatoria