Posts filed under ‘Resistencia bacteriana’

Salmonella blood stream infections in a tertiary care setting in Ghana.

BMC Infect Dis. 2014 Dec 21;14:3857.

Labi AK, Obeng-Nkrumah N, Addison NO, Donkor ES.



Despite the clinical significance of Salmonella infections, surveillance data worldwide remains limited and is more so exemplified by the lack of reports from Africa especially in eastern, central and western Africa. This study reports on Salmonella serotypes as significant causes of blood stream infections (BSI) and multidrug antibiotic resistance at Korle-Bu Teaching Hospital in Accra, Ghana.


Antibiogram patterns, seasonal variations in disease incidence and predisposing factors for infection with Salmonella serotypes were analyzed retrospectively over a 4-year period from January 2010 to December 2013. Blood cultures were processed with BACTEC 9240 blood culture system. Speciation was done with BBL Crystal Enteric/Nonfermenter identification system®, and with slide agglutination using specific antisera. Antimicrobial susceptibility testing was carried out by the Kirby-Bauer disc diffusion method according to Clinical and Laboratory Standard Institute guidelines.


We report a 6.5% (n=181/2768) prevalence of Salmonella bacteraemia at the Korle-Bu Teaching Hospital; with a preponderance of non-typhoidal salmonellae (NTS) over typhoidal salmonella (TS) (n=115/181, 63.5% versus n=66/181, 36.5%; P-value <0.002). Children under 5 years bore the brunt of the disease (n=93/174, 53.4%). Resistance to ciprofloxacin (n=1/127, 0.7%), amikacin (n=3/81, 3.7%), and cefotaxime (n=6/99, 6.1%) remained low, despite high levels of multidrug resistant Salmonella phenotypes (n=81/181, 44.2%). In multivariate analysis, and among patients with Salmonella BSI, those <1 year old had reduced risk of non-typhoidal infections [Odds ratio, 0.51; 95% confidence interval (95% CI), 0.16-0.92, P-value 0.021]. Similarly, patients with cefuroxime resistant strans were at increased risk of having multidrug resistant Salmonella BSI (OR, 8.97; 95% CI, 3.62-24.15; P-value, 0.001).


Salmonellae, predominantly NTS, account for a reasonable low proportion of positive blood cultures in our tertiary care setting; but with significant multidrug resistant phenotypes and low ciprofloxacin and cefotaxime resistance.



April 9, 2015 at 3:20 pm

How good is the evidence for the recommended empirical antimicrobial treatment of patients hospitalized because of community-acquired pneumonia? A systematic review.

J Antimicrob Chemother. 2003 Oct;52(4):555-63.

Oosterheert JJ1, Bonten MJ, Hak E, Schneider MM, Hoepelman IM.

1Division of Medicine, Department of Acute Medicine and Infectious Diseases, University Medical Centre Utrecht, PO Box 85500, 3508 GA Utrecht, The Netherlands.



For years, monotherapy with a beta-lactam antibiotic (penicillin, amoxicillin or second-generation cephalosporin) was recommended as empirical therapy for patients with community-acquired pneumonia (CAP). A combination of a beta-lactam and a macrolide antibiotic was only recommended for patients with severe CAP needing intensive care treatment or when atypical pathogens, i.e. Legionella pneumophila, Mycoplasma pneumoniae and Chlamydia pneumoniae, were strongly suspected. However, new guidelines recommend a combination of a beta-lactam antibiotic plus a macrolide or monotherapy with a fluoroquinolone for all patients hospitalized with CAP. We evaluated whether treatment with a beta-lactam plus macrolide or quinolone monotherapy is truly superior to beta-lactam treatment alone.


We systematically reviewed available studies, retrieved from MEDLINE and by hand-searching reference lists from recent reviews and guidelines on the effectiveness of recommended empirical antimicrobial treatment of patients hospitalized because of CAP.


Eight relevant studies were selected. In six studies significant reductions in mortality were found, in one study a reduction in hospital length of stay was found and in one study no beneficial effects could be demonstrated for treatment regimens with fluoroquinolone monotherapy or combinations of beta-lactams and macrolides. The beneficial value of macrolides or fluoroquinolones might be the result of a large and mainly unrecognized role of atypical pathogens in the aetiology of CAP, anti-inflammatory effects of macrolides or resistance to beta-lactams of the most important pathogens. However, the studies supporting the recommended treatment regimen were designed as non-experimental cohort studies. As a consequence, the results may have been influenced by confounding by indication. In addition, the outcomes showed several inconsistencies.


A randomized controlled trial is warranted to circumvent the methodological flaws in the designs of the currently available studies. Since the addition of macrolides or treatment with fluoroquinolones may lead to enhanced antibiotic resistance, increased side effects and healthcare-related costs, such a fundamental change in the treatment of CAP should be based on valid data.


April 5, 2015 at 10:00 pm

A review of Streptococcus pneumoniae infection treatment failures associated with fluoroquinolone resistance.

Clin Infect Dis. 2005 Jul 1;41(1):118-21.


Fuller JD1, Low DE.

1Department of Microbiology, Toronto Medical Laboratories and Mount Sinai Hospital, Toronto, Ontario, Canada.


We reviewed all of the published reports of cases of fluoroquinolone treatment failures for respiratory tract infection due to fluoroquinolone-resistant Streptococcus pneumoniae.

There were 20 ciprofloxacin and levofloxacin treatment failures reported.

Physicians should be aware, when treating pneumococcal respiratory tract infections in older patients with a fluoroquinolone, that clinical failures might occur, especially for patients with comorbid illnesses and a history of recent fluoroquinolone use.


April 5, 2015 at 9:57 pm

Antibiotic treatment strategies for community-acquired pneumonia in adults.

N Engl J Med APR.2, 2015 V.372  P.1312-1323

Douwe F. Postma, M.D., Cornelis H. van Werkhoven, M.D., Leontine J.R. van Elden, M.D., Ph.D., Steven F.T. Thijsen, M.D., Ph.D., Andy I.M. Hoepelman, M.D., Ph.D., Jan A.J.W. Kluytmans, M.D., Ph.D., Wim G. Boersma, M.D., Ph.D., Clara J. Compaijen, M.D., Eva van der Wall, M.D., Jan M. Prins, M.D., Ph.D., Jan J. Oosterheert, M.D., Ph.D., and Marc J.M. Bonten, M.D., Ph.D. for the CAP-START Study Group


The choice of empirical antibiotic treatment for patients with clinically suspected community-acquired pneumonia (CAP) who are admitted to non–intensive care unit (ICU) hospital wards is complicated by the limited availability of evidence. We compared strategies of empirical treatment (allowing deviations for medical reasons) with beta-lactam monotherapy, beta-lactam–macrolide combination therapy, or fluoroquinolone monotherapy.


In a cluster-randomized, crossover trial with strategies rotated in 4-month periods, we tested the noninferiority of the beta-lactam strategy to the beta-lactam–macrolide and fluoroquinolone strategies with respect to 90-day mortality, in an intention-to-treat analysis, using a noninferiority margin of 3 percentage points and a two-sided 90% confidence interval.


A total of 656 patients were included during the beta-lactam strategy periods, 739 during the beta-lactam–macrolide strategy periods, and 888 during the fluoroquinolone strategy periods, with rates of adherence to the strategy of 93.0%, 88.0%, and 92.7%, respectively. The median age of the patients was 70 years. The crude 90-day mortality was 9.0% (59 patients), 11.1% (82 patients), and 8.8% (78 patients), respectively, during these strategy periods. In the intention-to-treat analysis, the risk of death was higher by 1.9 percentage points (90% confidence interval [CI], −0.6 to 4.4) with the beta-lactam–macrolide strategy than with the beta-lactam strategy and lower by 0.6 percentage points (90% CI, −2.8 to 1.9) with the fluoroquinolone strategy than with the beta-lactam strategy. These results indicated noninferiority of the beta-lactam strategy. The median length of hospital stay was 6 days for all strategies, and the median time to starting oral treatment was 3 days (interquartile range, 0 to 4) with the fluoroquinolone strategy and 4 days (interquartile range, 3 to 5) with the other strategies.


Among patients with clinically suspected CAP admitted to non-ICU wards, a strategy of preferred empirical treatment with beta-lactam monotherapy was noninferior to strategies with a beta-lactam–macrolide combination or fluoroquinolone monotherapy with regard to 90-day mortality. (Funded by the Netherlands Organization for Health Research and Development; CAP-START number, NCT01660204.)


April 2, 2015 at 10:19 am

Adipocytes Armed against Staphylococcus aureus

N Engl J Med April 2, 2015 V.372 P.1368-1370

Lloyd S. Miller, M.D., Ph.D.

From the Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore.

Staphylococcus aureus is a harmless commensal microorganism in the skin and mucosa. However, S. aureus is also a deadly pathogen responsible for the vast majority of skin infections.

Moreover, it causes pneumonia, sepsis, organ abscesses, endocarditis, and osteomyelitis.

In Alexander Fleming’s laboratory, in 1928, the golden-colored colonies of this gram-positive bacterium grew throughout a petri dish, except on an edge contaminated by the mold Penicillium notatum.

This led to Fleming’s discovery of penicillin, the golden age of antibiotic agents, and then the dreaded consequence of antibiotic resistance…..


April 2, 2015 at 10:17 am

A Retrospective Review of the Clinical Experience of Linezolid with or Without Rifampicin in Prosthetic Joint Infections Treated with Debridement and Implant Retention.

Infect Dis Ther. 2014 Aug 20.

Morata L1, Senneville E, Bernard L, Nguyen S, Buzelé R, Druon J, Tornero E, Mensa J, Soriano A.

1Bone and Joint Infection Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer, Hospital Clínic of Barcelona, C/Villarroel 170, 08036, Barcelona, Spain,



Debridement and prosthesis retention, combined with a prolonged antibiotic regimen including rifampicin, is an accepted therapeutic approach when the duration of symptoms is less than 4 weeks and there are no radiological signs of loosening.

The outcome of patients managed with this strategy has been previously assessed in several articles with success rates of 60-90%.

This study aims to review the clinical experience with linezolid in 3 different hospitals from Spain and France in patients with prosthetic joint infection (PJI) managed with debridement, retention of the implant and treated with linezolid with or without rifampicin.


Patients with an acute PJI who underwent open debridement with implant retention treated with linezolid for more than 7 days in 3 hospitals from Barcelona, Tours and Lille between 2005 and 2011 were retrospectively reviewed. Relevant information about demographics, co-morbidity, type of implant, surgical treatment, microorganism isolated, antimicrobial therapy, adverse events (AEs) and outcomes were recorded from patients.


A total of 39 patients were retrospectively reviewed. The mean age (SD) was 70.5 (8.8) years and 9 patients had diabetes mellitus (23%). There were 25 (64%) knee prostheses, 13 (33%) hips and 1 shoulder (3%). The median interquartile range (IQR) days from arthroplasty to infection diagnosis was 17 (19-48) and 33 (85%) cases were diagnosed within the first 60 days. The median (IQR) duration of antibiotic treatment was 70.5 (34-96) days and the median (IQR) number of days on linezolid treatment was 44.5 (30-81). AEs were observed in 15 patients (38%), with gastrointestinal complaints in 8 cases and anemia in 5 being the most frequent. After a median (IQR) follow-up of 2.5 (1.8-3.6) years, there were 11 failures (28%) (8 relapses and 3 new infections). The failure rate was higher in the rifampicin group (36% vs. 18%) mainly due to a higher relapse rate (27% vs. 12%) although differences were not statistically significant.


Management of acute PJIs with debridement and retention of the implant linezolid, with or without rifampicin, is associated with a high remission rate and it is an alternative treatment for infections due to fluoroquinolone and/or rifampicin-resistant staphylococci.


March 29, 2015 at 10:40 am

Clinical characteristics and outcomes of prosthetic joint infection caused by small colony variant staphylococci.

MBio. 2014 Sep 30;5(5):e01910-14.

Tande AJ1, Osmon DR2, Greenwood-Quaintance KE3, Mabry TM4, Hanssen AD4, Patel R.


Small colony variants (SCVs) are naturally occurring subpopulations of bacteria.

The clinical characteristics and treatment outcomes of patients with prosthetic joint infection (PJI) caused by staphylococcal SCVs are unknown.

This study was a retrospective series of 113 patients with staphylococcal PJI, with prospective testing of archived sonicate fluid samples.

SCVs were defined using two-investigator review. Treatment failure was defined as

(i) subsequent revision surgery for any reason,

(ii) PJI after the index surgery,

(iii) prosthesis nonreimplantation due to ongoing infection, or

(iv) amputation of the affected limb.

There were 38 subjects (34%) with SCVs and 75 (66%) with only normal-phenotype (NP) bacteria.

Subjects with SCVs were more likely to have been on chronic antimicrobials prior to surgery (P = 0.048), have had prior surgery for PJI (P = 0.03), have had a longer duration of symptoms (P = 0.0003), and have had a longer time since joint implantation (P = 0.007), compared to those with only NP bacteria.

Over a median follow-up of 30.6 months, 9 subjects (24%) with SCVs and 23 (32%) with only NP bacteria experienced treatment failure (P = 0.51).

Subjects infected with Staphylococcus aureus were more likely to fail than were those infected with Staphylococcus epidermidis (hazard ratio [HR], 4.03; 95% confidence interval [CI], 1.80 to 9.04).

While frequently identified in subjects with PJI and associated with several potential predisposing factors, SCVs were not associated with excess treatment failure compared to NP infections in this study, where they were primarily managed with two-stage arthroplasty exchange.


Bacteria with the small colony variant (SCV) phenotype are described in small case series as causing persistent or relapsing infection, but there are insufficient data to suggest that they should be managed differently than infection with normal-phenotype bacteria. In an effort to investigate the clinical importance of this phenotype, we determined whether SCVs were present in biofilms dislodged from the surfaces of arthroplasties of patients with staphylococcal prosthetic joint infection and assessed the clinical outcomes associated with detection of SCVs. We found that prosthetic joint infection caused by SCV staphylococci was associated with a longer duration of symptoms and more prior treatment for infection but not with an increased rate of treatment failure, compared to infection caused by normal-phenotype staphylococci.


March 25, 2015 at 8:26 am

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