CONTEXT Ceftriaxone, an expanded-spectrum cephalosporin, is an
antimicrobial agent commonly used to treat severe Salmonella
infections, especially in children. Ceftriaxone-resistant
Salmonella ...infections have recently been reported in the
United States, but the extent of the problem is unknown. OBJECTIVES To summarize national surveillance data for
ceftriaxone-resistant Salmonella infections in the United
States and to describe mechanisms of resistance. DESIGN AND SETTING Case series and laboratory evaluation of human
isolates submitted to the Centers for Disease Control and Prevention
from 17 state and community health departments participating in the
National Antimicrobial Resistance Monitoring System (NARMS) for enteric
bacteria between 1996 and 1998. PATIENTS Patients with ceftriaxone-resistant Salmonella
infections between 1996 and 1998 were interviewed and isolates with
decreased ceftriaxone susceptibility were further characterized. MAIN OUTCOME MEASURES Exposures and illness outcomes, mechanisms
of resistance. RESULTS The prevalence of ceftriaxone-resistant
Salmonella was 0.1% (1 of 1326) in 1996, 0.4% (5 of 1301) in
1997, and 0.5% (7 of 1466) in 1998. Ten (77%) of the 13 patients with
ceftriaxone-resistant infections were aged 18 years or younger. The
patients lived in 8 states (California, Colorado, Kansas,
Massachusetts, Maryland, Minnesota, New York, and Oregon).
Nine (82%) of 11 patients interviewed did not take antimicrobial
agents and 10 (91%) did not travel outside the United States before
illness onset. Twelve of the 15 Salmonella isolates with
ceftriaxone minimum inhibitory concentrations of
16 µg/mL or higher
were serotype Typhimurium but these isolates had different pulsed-field
gel electrophoresis patterns. Thirteen of these 15 isolates collected
between 1996 and 1998 were positive for a 631–base pair polymerase
chain reaction product obtained by using primers specific for the
ampC gene of Citrobacter freundii. CONCLUSIONS Domestically acquired ceftriaxone-resistant
Salmonella has emerged in the United States. Most
ceftriaxone-resistant Salmonella isolates had similar AmpC
plasmid-mediated resistance.
Larval and juvenile herring Clupea harengus collected in the Polish part of the Vistula Lagoon in May-July 1997 had hatched between 17 April and 9 June and originated from three cohorts. The spawning ...season began on 1 March at 3.8 parallel C and was completed on 3 June at 12.7 parallel C. Mortality among larvae was high in the first 2 weeks of April, probably associated with significant temperature decrease at the beginning of the spawning season. The growth of 10-48mm L sub(S)herring was linear, highest for larvae and juveniles from the first cohort (0.58mmmm super(1)day super(1)), slower for the second cohort (0.55mmmm super(1)day super(1)) and the slowest for the third cohort (0.45mmmmday super(1)). Temperature effects on the growth were inconclusive and potentially unfavourable feeding conditions in June might have been responsible for the relatively slow growth of third cohort larvae and juveniles. Relationships between otolith size (perimeter, length, width, area, and weight) and fish size (L sub(S)) differed among the three cohorts, related mostly to the positive temperature effect on otolith growth, individuals growing in warmer water had larger otoliths. Although a negative growth rate effect was observed as well, it was less significant. Copyright 2001 The Fisheries Society of the British Isles
Staphylococcus epidermidis is the most common cause of orthopaedic prosthetic device infections. Polysaccharide intercellular adhesin (PIA) is important in the pathogenesis of intravascular ...catheter-associated infection, and has an essential role in cellular aggregation and biofilm formation. However, the role of PIA in orthopaedic infections is less well understood. We used genetically defined strains of S. epidermidis in an in vitro adherence assay to assess the importance of PIA in the adherence to various orthopaedic biomaterials. On all biomaterials tested (zirconia, ultra-high molecular weight polyethylene, polymethylmethacrylate, cobalt chromium, titanium, stainless steel, and silastic), PIA-positive S. epidermidis 1457 exhibited greater levels of adherence thanS. epidermidis 1457 M10, an isogenic icaA Tn917 mutant. PIA appears to play a critical role in the adherence of S. epidermidis to orthopaedic biomaterials, and may serve as an important virulence determinant in orthopaedic prosthetic device infections.
Marginal otolith increment width analysis was performed on field‐collected larval and juvenile spring‐spawned herring Clupea harengus that experienced variable feeding conditions and high ...temperatures that were above the optimum for growth. Although drastic zooplankton biomass reduction had a significant effect on increment width, a delay of a few days in the otolith response was observed. More importantly, a very clear, positive temperature effect on marginal increment width was demonstrated in fish characterized by temperature independent somatic growth. These results indicate that under natural conditions it may be impossible to distinguish increment width changes related to variation in feeding conditions from changes caused by temperature fluctuations. Therefore, it was concluded that marginal otolith increment width analysis could not be used as a recent growth index (IG) for herring larvae and juveniles exposed to drastic temperature fluctuations. The implication of these results is significant not only for the use of marginal increments as a recent growth index, but also if growth rate backcalculation is to be used as a research method.
1,3 Departments of Pathology and Microbiology 1 and Internal Medicine 3 , University of Nebraska Medical Center, Omaha, NE, USA 2 Department of Microbiology, Royal College of Surgeons in Ireland, ...Dublin, Ireland 4 Department of Biology, University of Nebraska-Lincoln, Lincoln, NE, USA
Correspondence P. D. Fey pfey{at}unmc.edu
Received July 3, 2003
Accepted January 15, 2004
Production of biofilm in Staphylococcus epidermidis is mediated through enzymes produced by the four-gene operon ica and is subject to phenotypic variation. The purpose of these experiments was to investigate the regulation of ica and icaR transcription in phenotypic variants produced by multiple unrelated isolates of S. epidermidis . Ten isolates were chosen for the study, four of which contained IS 256 . IS 256 mediates a reversible inactivation of ica in approximately 30 % of phenotypic variants. All ten strains produced at least two types of phenotypic variant (intermediate and smooth) in which biofilm formation was significantly impaired. Reversion studies indicated that all phenotypic variants were stable after overnight growth, but began to revert to other phenotypic forms after 5 days of incubation at 37 °C. ica transcriptional analysis was performed on phenotypic variants from three IS 256 -negative isolates; 1457, SE5 and 14765. This analysis demonstrated that ica transcription was significantly reduced in the majority of phenotypic variants, although two variants from SE5 and 1457 produced wild-type quantities of ica transcript. Analysis of seven additional phenotypic variants from SE5 revealed that ica expression was only reduced in three. Expression of icaR transcript was unaffected in all smooth phenotypic variants. Mutations within ica were identified in two SE5 variants with wild-type levels of ica transcription. It is concluded that mutation and transcriptional regulation of ica are the primary mechanisms that govern phenotypic variation of biofilm formation within IS 256 -negative S. epidermidis .
These authors contributed equally to this work.
Abbreviations: CRA, Congo red agar; PIA, polysaccharide intercellular adhesin.
The GenBank accession number for the ica sequence of Staphylococcus epidermidis isolate SE5 is AY138959 .
Supplementary figures and a table are available in JMM Online.
Extended spectrum beta-lactamase (ESBL)-producing organisms pose unique challenges to clinical microbiologists, clinicians, infection control professionals and antibacterial-discovery scientists. ...ESBLs are enzymes capable of hydrolysing penicillins, broad-spectrum cephalosporins and monobactams, and are generally derived from TEM and SHV-type enzymes. ESBLs are often located on plasmids that are transferable from strain to strain and between bacterial species. Although the prevalence of ESBLs is not known, it is clearly increasing, and in many parts of the world 10-40% of strains of Escherichia coli and Klebsiella pneumoniae express ESBLs. ESBL-producing Enterobacteriaceae have been responsible for numerous outbreaks of infection throughout the world and pose challenging infection control issues. Clinical outcomes data indicate that ESBLs are clinically significant and, when detected, indicate the need for the use of appropriate antibacterial agents. Unfortunately, the laboratory detection of ESBLs can be complex and, at times, misleading. Antibacterial choice is often complicated by multi-resistance. Many ESBL-producing organisms also express AmpC beta-lactamases and may be co-transferred with plasmids mediating aminoglycoside resistance. In addition, there is an increasing association between ESBL production and fluoroquinolone resistance. Although in in vitro tests ESBLs are inhibited by beta-lactamase inhibitors such as clavulanic acid, the activity of beta-lactam/beta-lactamase inhibitor combination agents is influenced by the bacterial inoculum, dose administration regimen and specific type of ESBL present. Currently, carbapenems are regarded as the drugs of choice for treatment of infections caused by ESBL-producing organisms. Unfortunately, use of carbapenems has been associated with the emergence of carbapenem-resistant bacterial species such as Stenotrophomonas sp. or Pseudomonas sp.
Summary Background Erythropoiesis-stimulating agents reduce anaemia in patients with cancer and could improve their quality of life, but these drugs might increase mortality. We therefore did a ...meta-analysis of randomised controlled trials in which these drugs plus red blood cell transfusions were compared with transfusion alone for prophylaxis or treatment of anaemia in patients with cancer. Methods Data for patients treated with epoetin alfa, epoetin beta, or darbepoetin alfa were obtained and analysed by independent statisticians using fixed-effects and random-effects meta-analysis. Analyses were by intention to treat. Primary endpoints were mortality during the active study period and overall survival during the longest available follow-up, irrespective of anticancer treatment, and in patients given chemotherapy. Tests for interactions were used to identify differences in effects of erythropoiesis-stimulating agents on mortality across prespecified subgroups. Findings Data from a total of 13 933 patients with cancer in 53 trials were analysed. 1530 patients died during the active study period and 4993 overall. Erythropoiesis-stimulating agents increased mortality during the active study period (combined hazard ratio cHR 1·17, 95% CI 1·06–1·30) and worsened overall survival (1·06, 1·00–1·12), with little heterogeneity between trials ( I2 0%, p=0·87 for mortality during the active study period, and I2 7·1%, p=0·33 for overall survival). 10 441 patients on chemotherapy were enrolled in 38 trials. The cHR for mortality during the active study period was 1·10 (0·98–1·24), and 1·04 (0·97–1·11) for overall survival. There was little evidence for a difference between trials of patients given different anticancer treatments (p for interaction=0·42). Interpretation Treatment with erythropoiesis-stimulating agents in patients with cancer increased mortality during active study periods and worsened overall survival. The increased risk of death associated with treatment with these drugs should be balanced against their benefits. Funding German Federal Ministry of Education and Research, Medical Faculty of University of Cologne, and Oncosuisse (Switzerland).
Urinary tract infections (UTIs) are the most common nosocomial infection experienced by patients in United States hospitals and are responsible for significant morbidity and excess hospital costs. ...The purpose of this study was to determine the efficacy of a silver alloy, hydrogel-coated, urinary catheter in the prevention of catheter-associated UTI, to assess the cost effectiveness of the coated catheter, and to test for the emergence of silver-resistance in urinary microbial isolates.
A 2-year prospective surveillance study in 10 patient care units was conducted to determine the rate of catheter-associated UTI. Historic control data was utilized to assess the effect of the coated catheter. A cost-effectiveness analysis was conducted using a range of cost estimates. Silver susceptibility was determined for microbes responsible for catheter-associated UTI.
Data were analyzed using a Poisson regression model. The rate of catheter-associated UTI fell from 6.13/1000 catheter-days during the period 1999-2000 to 2.62/1000 catheter-days during 2001-2002 (
P
=
.002). Calculated cost savings varied widely. Modest savings were achieved at the realistic lower cost estimates. No silver-resistant microbes were recovered in the susceptibility tests.
The introduction of a silver alloy, hydrogel-coated urinary catheter was associated with a significant decline in nosocomial UTI and cost savings over the range of cost estimates. Silver-resistant urinary pathogens were not recovered from patients experiencing catheter-associated UTI during the study period.
Background. Needleless intravascular catheter connector valves have been introduced into clinical practice to minimize the risk of needlestick injury. However, infection-control risks associated with ...these valves may be underappreciated. In March 2005, a dramatic increase in bloodstream infections was noted in multiple patient care units of a hospital in temporal association with the introduction of a needleless valve into use. Methods. Surveillance for primary bloodstream infection was conducted using standard methods throughout the hospital. Blood culture contamination rates were monitored. Cultures were performed using samples obtained from intravascular catheter connector valves. Results. The relative risk of bloodstream infection for the time period in which the suspect connector valve was in use, compared with baseline, was 2.79 (95% confidence interval, 2.27–3.43). In critical care units, the rate of primary bloodstream infection increased with the introduction of the valve from 3.87 infections per 1000 catheter-days to 10.64 infections per 1000 catheter-days (P < .001), and it decreased to 5.59 infections per 1000 catheter-days (P = .02) in the 6 months following removal of the device from use. Similarly, in inpatient nursing units, the rate of bloodstream infection increased from 3.47 infections per 1000 catheter-days to 7.3 infections per 1000 catheter-days (P = .02) following introduction of the device, and it decreased to 2.88 infections per 1000 catheter-days (P = .57) following removal of the device from use. Similar events occurred in the cooperative care units. The rate of blood culture contamination did not substantially change over the course of the study. Of 37 valves that were subjected to microbiological sample testing, 24.3% yielded microbes, predominantly coagulase-negative staphylococci. Conclusion. A significant association between primary bloodstream infection and a needleless connector valve was observed. Evaluation of needleless connector valves should include a thorough assessment of infection risks in prospective randomized trials prior to their introduction to the market.
This work presents biological information for polar cod (Boreogadus saida) collected with a Campelen 1800 shrimp bottom trawl in Kongsfjorden (two stations located in the inner part of the fjord ...adjacent to the glacier) and Rijpfjorden (one station at the entrance to the fjord) in September and October 2013. The otolith-based ages of polar cod collected in Kongsfjorden (6.1–24cm total length TL; n=813) ranged from 0 to 4 years. The growth rate was relatively constant at approximately 4.7cmyear−1 between years 1 and 4, which indicates that growth was fast in the glacier area. The ages of polar cod collected in Rijpfjorden (8.6–15.9cm TL; n=64) ranged from 2 to 3 years. The fish from Rijpfjorden were smaller at age than those from Kongsfjorden, and their growth rate between years 2 and 3 (no other age classes were available) was approximately 3.3cmyear−1. In both fjords, males and females were of the same size-at-age and the same weight-at-TL. The small sampling area means that the results on growth rate are not representative of the entire fjords. Instead, the results can be discussed as presenting the possible growth rates of some populations. A strong relationship was identified between otolith size (length and weight) and fish size (TL and TW), with no differences between males and females or the fjords. A significant, strong relationship was also noted between fish and otolith growth rates.
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