Posts filed under ‘Resistencia bacteriana’

Empirical antibiotic therapy for pneumonia in intensive care units: a multicentre, retrospective analysis of potentially pathogenic microorganisms identified by endotracheal aspirates cultures

European J of Clinical Microb & Inf Dis  V.34  N.10

B. J. Scholte, H. L. Duong, C. Linssen

The purpose of this investigation was to explore the presumed relationship between the days of hospitalisation and microorganisms identified by endotracheal aspirate cultures in relation to adequate empirical treatment strategies of pneumonia in the intensive care unit (ICU).

All potentially pathogenic microorganisms identified by (surveillance) cultures of endotracheal aspirates obtained in the ICUs of two Dutch teaching hospitals in 2007 and 2012 were retrospectively collected and analysed.

Antibiotic susceptibilities to 11 antibiotics were calculated for several time points (days or weeks) after hospital admission and expressed per patient-day. In total, 4184 potentially pathogenic microorganisms identified in 782 patients were analysed.

Prevalence of the classic early-onset pneumonia-causing microorganisms decreased from 55 % on the first four days to 34 % on days 4–6 after hospital admission (p<0.0001). Susceptibility to amoxicillin/clavulanic acid was below 70 % on all days.

Except for days 0 and 12, susceptibility to ceftriaxone was below 80 %. The overall susceptibility to piperacillin/tazobactam was 1518/1973 (77 %) in 2007 vs. 727/1008 (67 %) in 2012 (p<0.0001). After day 8 of hospital admission, susceptibility to piperacillin/tazobactam therapy was below 80 % in 2012.

After one week of hospital admission, susceptibilities to antibiotics were lower in the hospital that included that antibiotic in the local empirical treatment protocols as compared to the hospitals in which that antibiotic was not or infrequently included: 90/434 (21 %) vs. 117/398 (29 %); p=0.004 for amoxicillin/clavulanic acid and 203/433 (47 %) vs. 253/398 (64 %); p<0.001 for ceftriaxone.

No cut-off in the number of days after hospital admission could be identified to distinguish early-onset from late-onset pneumonia.

Consequently, the choice of empirical antibiotics should probably not be based on the time of onset.




October 3, 2015 at 5:29 pm

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) infections: are carbapenem alternatives achievable in daily practice?

Int J Infect Dis. 2015 Sep 12;39:62-67.

Pilmis B1, Delory T2, Groh M3, Weiss E4, Emirian A5, Lecuyer H6, Lesprit P2, Zahar JR7.

Author information

1Université Paris Descartes, Hôpital Necker Enfants Malades, Service de Maladies Infectieuses et Tropicales, Paris, France; Groupe Hospitalier Paris Saint-Joseph, Equipe Mobile de Microbiologie Clinique, Paris, France.

2Université Paris XII, Hôpital Henri Mondor, Unité de Contrôle Épidémiologique et Prévention de l’Infection, Créteil, France.

3Université Paris Descartes, Hôpital Cochin, Service de Médecine Interne, Paris, France.

4Université Paris Diderot, Hôpital Beaujon, Département d’Anesthésie-Réanimation, Clichy, France.

5Université Paris XII, Hôpital Henri Mondor, Laboratoire de Bactériologie-Hygiène, Département de Virologie, Bactériologie-Hygiène, Parasitologie-Mycologie, Créteil, France.

6Université Paris Descartes, Hôpital Necker Enfants Malades, Laboratoire de Microbiologie, Paris, France.

7Université d’Angers, Unité de Prévention et de Lutte Contre les Infections Nosocomiales, CHU d’Angers, 4 rue Larrey, 49000 Angers, France. Electronic address:



To avoid the use of carbapenems, alternatives such as cephamycin, piperacillin-tazobactam, and others are suggested for the treatment of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) infections. The aim of this study was to evaluate the frequency and the feasibility of antimicrobial de-escalation for ESBL-PE-related infections.


A prospective observational, bi centric cohort study was conducted. All patients with ESBL-PE infections were included. De-escalation was systematically suggested if patients were clinically stable and the isolate was susceptible to possible alternatives.


Seventy-nine patients were included: 36 (45.6%) were children, 27 (34.1%) were hospitalized in intensive care units, and 37 (47%) were immunocompromised. Urinary tract infections, pneumonia, and catheter-related bloodstream infections accounted for 45.6%, 19%, and 10%, respectively, of the cohort. Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae were the three most frequent causative organisms isolated. On day 5, 47 (59.2%) of the patients were still receiving carbapenems. Antimicrobial resistance (44.7%), infection relapse (26.9%), and clinical instability (19.2%) were the most important reasons for not prescribing alternatives. E. coli-related infections appeared to be a protective factor against maintaining the carbapenem prescription (odds ratio 0.11, 95% confidence interval 0.041-0.324; p=0.0013).


In clinical practice, less than 50% of patients with ESBL-PE-related infections were de-escalated after empirical treatment with carbapenems.



October 2, 2015 at 9:10 am

New Delhi Metallo-β-Lactamase 1(NDM-1), the Dominant Carbapenemase Detected in Carbapenem-Resistant Enterobacter cloacae from Henan Province, China.

PLoS One. 2015 Aug 11;10(8):e0135044.

Liu C1, Qin S2, Xu H1, Xu L1, Zhao D2, Liu X3, Lang S4, Feng X1, Liu HM2.

Author information

1Department of clinical laboratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, PR China; Henan province Key Laboratory of Medicine, Zhengzhou, PR China.

2School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, PR China.

3Department of clinical laboratory, The central hospital of Zhumadian city, Zhumadian, PR China.

4Department of clinical laboratory, The central hospital of Sanmenxia city, Sanmenxia, PR China.


The emergence of New Delhi metallo-β-lactamase 1 (NDM-1) has become established as a major public health threat and represents a new challenge in the treatment of infectious diseases.

In this study, we report a high incidence and endemic spread of NDM-1-producing carbapenem-resistant Enterobacter cloacae isolates in Henan province, China.

Eight (72.7%) out of eleven non-duplicated carbapenem-resistant E. cloacae isolates collected between June 2011 and May 2013 were identified as NDM-1 positive.

The blaNDM-1 gene surrounded by an entire ISAba125 element and a bleomycin resistance gene bleMBL in these isolates were carried by diverse conjugatable plasmids (IncA/C, IncN, IncHI2 and untypeable) ranging from ~55 to ~360 kb.

Molecular epidemiology analysis revealed that three NDM-1-producing E. cloacae belonged to the same multilocus sequence type (ST), ST120, two of which were classified as extensively drug-resistant (XDR) isolates susceptible only to tigecycline and colistin.

The two XDR ST120 E. cloacae isolates co-harbored blaNDM-1, armA and fosA3 genes and could transfer resistance to carbapenems, fosfomycin and aminoglycosides simultaneously via a conjugation experiment.

Our study demonstrated NDM-1 was the most prevalent metallo-β-lactamase (MBL) among carbapenem-resistant E. cloacae isolates and identified a potential endemic clone of ST120 in Henan province.

These findings highlight the need for enhanced efforts to monitor the further spread of NDM-1 and XDR ST120 E. cloacae in this region.


October 2, 2015 at 9:07 am

Distinct but spatially overlapping intestinal niches for vancomycin-resistant Enterococcus faecium and carbapenem-resistant Klebsiella pneumoniae. 

PLoS Pathog 2015 Sep 3; 11:e1005132.

Silvia Caballero, Rebecca Carter, Xu Ke, Bože Sušac, Ingrid M. Leiner, Grace J. Kim, Liza Miller, Lilan Ling, Katia Manova, Eric G. Pamer

Silvia Caballero, Rebecca Carter, Bože Sušac, Ingrid M. Leiner, Eric G. Pamer

Immunology Program and Infectious Disease Service, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America

Silvia Caballero, Eric G. Pamer

Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, New York, United States of America

Xu Ke, Katia Manova

Molecular Cytology Core Facility, Sloan-Kettering Institute, New York, New York, United States of America

Grace J. Kim, Liza Miller, Lilan Ling, Eric G. Pamer

Lucille Castori Center for Microbes, Inflammation and Cancer, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America

Corresponding Author:

Antibiotic resistance among enterococci and γ-proteobacteria is an increasing problem in healthcare settings. Dense colonization of the gut by antibiotic-resistant bacteria facilitates their spread between patients and also leads to bloodstream and other systemic infections.

Antibiotic-mediated destruction of the intestinal microbiota and consequent loss of colonization resistance are critical factors leading to persistence and spread of antibiotic-resistant bacteria.

The mechanisms underlying microbiota-mediated colonization resistance remain incompletely defined and are likely distinct for different antibiotic-resistant bacterial species.

It is unclear whether enterococci or γ-proteobacteria, upon expanding to high density in the gut, confer colonization resistance against competing bacterial species.

Herein, we demonstrate that dense intestinal colonization with vancomycin-resistant Enterococcus faecium (VRE) does not reduce in vivo growth of carbapenem-resistant Klebsiella pneumoniae.

Reciprocally, K. pneumoniae does not impair intestinal colonization by VRE. In contrast, transplantation of a diverse fecal microbiota eliminates both VRE and K. pneumoniae from the gut.

Fluorescence in situ hybridization demonstrates that VRE and K. pneumoniae localize to the same regions in the colon but differ with respect to stimulation and invasion of the colonic mucus layer.

While VRE and K. pneumoniae occupy the same three-dimensional space within the gut lumen, their independent growth and persistence in the gut suggests that they reside in distinct niches that satisfy their specific in vivo metabolic needs.



October 1, 2015 at 12:39 pm

Usefulness of previous methicillin-resistant Staphylococcus aureus screening results in guiding empirical therapy for S aureus bacteremia.

Can J Infect Dis Med Microbiol. 2015 Jul-Aug;26(4):201-6.

Bai AD1, Burry L2, Showler A3, Steinberg M4, Ricciuto D5, Fernandes T6, Chiu A6, Raybardhan S7, Tomlinson GA8, Bell CM9, Morris AM10.

Author information

1Faculty of Medicine, University of Ottawa, Ottawa;

2Mount Sinai Hospital, University of Toronto, Toronto; ; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto;

3Department of Medicine, University of Toronto, Toronto; ; Division of Infectious Diseases, University of Toronto, Toronto;

4Mount Sinai Hospital, University of Toronto, Toronto;

5Department of Medicine, University of Toronto, Toronto; ; Division of Infectious Diseases, University of Toronto, Toronto; ; Lakeridge Health, Oshawa, Queen’s University, Kingston; ; Department of Medicine, Queen’s University, Kingston;

6Trillium Health Partners, Mississauga;

7North York General Hospital, Toronto, Ontario.

8Department of Medicine, University of Toronto, Toronto; ; University Health Network, Toronto, Ontario.

9Mount Sinai Hospital, University of Toronto, Toronto; ; Department of Medicine, University of Toronto, Toronto; ; University Health Network, Toronto, Ontario ; Institute for Clinical Evaluative Sciences, Toronto, Ontario.

10Mount Sinai Hospital, University of Toronto, Toronto; ; Department of Medicine, University of Toronto, Toronto; ; Division of Infectious Diseases, University of Toronto, Toronto; ; University Health Network, Toronto, Ontario.


Staphylococcus aureus bacteremia (SAB) is an important infection. Methicillin-resistant S aureus (MRSA) screening is performed on hospitalized patients for infection control purposes.


To assess the usefulness of past MRSA screening for guiding empirical antibiotic therapy for SAB.


A retrospective cohort study examined consecutive patients with confirmed SAB and previous MRSA screening swab from six academic and community hospitals between 2007 and 2010. Diagnostic test properties were calculated for MRSA screening swab for predicting methicillin resistance of SAB.


A total of 799 patients underwent MRSA screening swabs before SAB. Of the 799 patients, 95 (12%) had a positive and 704 (88%) had a negative previous MRSA screening swab. There were 150 (19%) patients with MRSA bacteremia. Overall, previous MRSA screening swabs had a positive likelihood ratio of 33 (95% CI 18 to 60) and a negative likelihood ratio of 0.45 (95% CI 0.37 to 0.54). Diagnostic accuracy differed depending on mode of acquisition (ie, community-acquired, nosocomial or health care-associated infection) (P<0.0001) and hospital (P=0.0002). At best, for health care-associated infection, prior MRSA screening swab had a positive likelihood ratio of 16 (95% CI 9 to 28) and a negative likelihood ratio of 0.27 (95% CI 0.17 to 0.41).


A negative prior MRSA screening swab cannot reliably rule out MRSA bacteremia and should not be used to guide empirical antibiotic therapy for SAB. A positive prior MRSA screening swab greatly increases likelihood of MRSA, necessitating MRSA coverage in empirical antibiotic therapy for SAB.


September 29, 2015 at 7:59 pm

Systematic Review and Meta-Analysis of the Epidemiology of Vancomycin-Intermediate and Heterogeneous Vancomycin-Intermediate Staphylococcus aureus Isolates.

PLoS One. 2015 Aug 19;10(8):e0136082. .

Zhang S1, Sun X2, Chang W2, Dai Y2, Ma X2.

Author information

1School of Medicine, Shandong University, Ji’nan, 250061, PR China.

2Department of Clinical Laboratory, Affiliated Provincial Hospital of Anhui Medical University, Hefei, 230001, PR China.



Vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) are associated with vancomycin treatment failure, and are becoming an increasing public health problem. Therefore, we undertook this study of 91 published studies and made subgroup comparisons of hVISA/VISA incidence in different study years, locations, and types of clinical samples. We also analyzed the genetic backgrounds of these strains.


A systematic literature review of relevant articles published in PubMed and EMBASE from January 1997 to August 2014 was conducted. We selected and assessed journal articles reporting the prevalence rates of hVISA/VISA.


The pooled prevalence of hVISA was 6.05% in 99,042 methicillin-resistant S. aureus (MRSA) strains and that of VISA was 3.01% in 68,792 MRSA strains. The prevalence of hVISA was 4.68% before 2006, 5.38% in 2006-2009, and 7.01% in 2010-2014. VISA prevalence was 2.05%, 2.63%, and 7.93%, respectively. In a subgroup analysis of different isolation locations, the prevalence of hVISA strains was 6.81% in Asia and 5.60% in Europe/America, and that of VISA was 3.42% and 2.75%, respectively. The frequencies of hVISA isolated from blood culture samples and from all clinical samples were 9.81% and 4.68%, respectively, and those of VISA were 2.00% and 3.07%, respectively. The most prevalent genotype was staphylococcal cassette chromosome mec (SCCmec) II, which accounted for 48.16% and 37.74% of hVISA and VISA, respectively. Sequence Type (ST) 239 was most prevalent.


The prevalence of hVISA/VISA has been increasing in recent years, but has been grossly underestimated. Its incidence is higher in Asia than in Europe/America. hVISA is isolated from blood culture samples more often than from other samples. These strains are highly prevalent in epidemic MRSA strains. This study clarifies the epidemiology of hVISA/VISA and indicates that the detection of these strains and the control of nosocomial infections must be strengthened.


September 29, 2015 at 7:57 pm

Bloodstream infections in intensive care unit patients: distribution and antibiotic resistance of bacteria.

Infect Drug Resist. 2015 Aug 10;8:287-96.

Russotto V1, Cortegiani A1, Graziano G2, Saporito L2, Raineri SM1, Mammina C2, Giarratano A1.

Author information

1Department of Biopathology and Medical Biotechnologies (DIBIMED), Section of Anaesthesia, Analgesia, Intensive Care and Emergency, Paolo Giaccone University Hospital, University of Palermo, Palermo, Italy.

2Department of Sciences for Health Promotion and Mother-Child Care, University of Palermo, Palermo, Italy.


Bloodstream infections (BSIs) are among the leading infections in critically ill patients. The case-fatality rate associated with BSIs in patients admitted to intensive care units (ICUs) reaches 35%-50%.

The emergence and diffusion of bacteria with resistance to antibiotics is a global health problem. Multidrug-resistant bacteria were detected in 50.7% of patients with BSIs in a recently published international observational study, with methicillin resistance detected in 48% of Staphylococcus aureus strains, carbapenem resistance detected in 69% of Acinetobacter spp., in 38% of Klebsiella pneumoniae, and in 37% of Pseudomonas spp.

Prior hospitalization and antibiotic exposure have been identified as risk factors for infections caused by resistant bacteria in different studies.

Patients with BSIs caused by resistant strains showed an increased risk of mortality, which may be explained by a higher incidence of inappropriate empirical therapy in different studies.

The molecular genetic characterization of resistant bacteria allows the understanding of the most common mechanisms underlying their resistance and the adoption of surveillance measures.

Knowledge of epidemiology, risk factors, mechanisms of resistance, and outcomes of BSIs caused by resistant bacteria may have a major influence on global management of ICU patients.

The aim of this review is to provide the clinician an update on BSIs caused by resistant bacteria in ICU patients.


September 29, 2015 at 7:55 pm

Older Posts


October 2015
« Sep    

Posts by Month

Posts by Category


Get every new post delivered to your Inbox.

Join 85 other followers