Epidemiology of extended-spectrum beta-lactamase-producing Enterobacteriaceae in a UK district hospital; an observational study.

BACKGROUND: Extended-spectrum beta-lactamases (ESBLs) are an increasingly important cause of resistance in Gram-negative bacteria throughout the world. AIM: We investigated the clinical and molecular epidemiology of infections caused by ESBL-producing Enterobacteriaceae in a UK hospital, to identify the types of ESBL produced and risk factors for acquisition. METHODS: Between July 2008 and June 2009, all patients yielding ESBL-producing Enterobacteriaceae from any clinical specimen were prospectively investigated using a questionnaire. API20E was used for bacterial identification; susceptibility testing and ESBL production were assessed by BSAC disc diffusion and cefpodoxime-clavulanate synergy tests, respectively. Polymerase chain reaction was used to screen a subset of isolates for bla(CTX-M) genes, to assign Escherichia coli isolates to their phylogenetic groups, and to identify members of the uropathogenic ST131 lineage. RESULTS: The overall prevalence of ESBL producers among clinical samples yielding Enterobacteriaceae was 1%; ESBL producers, obtained from 124 patients, were E. coli (N = 105), Klebsiella pneumoniae (N = 12), and others (N = 7). The main risk factors identified include recent antibiotic use (93%) and presence of a urinary catheter (24%). CTX-M group 1 ESBLs dominated (in 59 of 78, 76%, isolates studied). Most E. coli (35 of 56 tested) were phylogroup B2; of these, 23 belonged to the ST131 clone, 12 were phylogroup D, and four each belonged to phylogroups A and B1. CONCLUSION: ESBLs are an uncommon but significant problem in north-west Cambridgeshire. CTX-M-type enzymes were found in 75% of ESBL-positive isolates. All but two patients had at least one recognized risk factor. This study supports the requirement for interventions to reduce inappropriate urinary catheterization and antibiotic prescribing.

MRSA surveillance in a UK district hospital: measuring clinical isolates with MRSA is more useful than measuring MRSA bacteraemias.

The introduction of mandatory surveillance of meticillin-resistant Staphylococcus aureus (MRSA) bacteraemias and targets in England has led to reductions in most hospitals. However, reductions were difficult to demonstrate at Peterborough & Stamford Hospitals NHS Foundation Trust as MRSA bacteraemia was already an uncommon event. The authors questioned the efficacy of monitoring bacteraemias in a low-prevalence hospital, and this study sought to determine the accuracy of measuring bacteraemias compared with all clinical isolates (excluding bacteraemias; e.g. wound, sputa, urine) to assess the effectiveness of interventions. Over the six-year study period, a significant reduction was seen in MRSA in clinical specimens and new MRSA carriers identified by screening, whereas the MRSA bacteraemia rate remained at low levels. The measurement of clinical isolates may be more useful for assessment of the effectiveness of interventions now that MRSA bacteraemia rates have fallen to low levels almost universally across the UK.

Outcome for Gram-negative bacteraemia when following restrictive empirical antibiotic guidelines.

INTRODUCTION: Restrictions in prescribing broad spectrum antimicrobials have been part of a strategy to reduce Clostridium difficile cases in the UK in recent years. However, there has been little work on assessing the safety of alternative antimicrobial agents. METHODS: We performed an uncontrolled prospective observational survey over a 1-year period to determine the effectiveness and safety of a new antimicrobial stewardship programme in a district hospital in the UK. RESULTS: In total, 227 Gram-negative bacteraemias (203 episodes) occurred in the study period. Guidelines were adequate in 194 of 203 (95%) episodes and 163 episodes (80.2%) received adequate therapy. Patients in the inadequate therapy group had >2-fold increased likelihood of death [odds ratio (OR) = 2.63, 95% confidence interval (CI) = 1.09-6.34] within 30 days and >6-fold increased risk of death (OR = 6.40, 95% CI = 2.22-18.45) within 1 week when compared to patients in the adequate therapy group. Failure to administer gentamicin was the principal reason for not following the guidelines (18 episodes). Eight of these 18 episodes were susceptible to cefuroxime and two of these patients died. DISCUSSION: Adherence to the guidelines was associated with a correct empirical antibiotic choice and reduced mortality. This study also demonstrates the importance of adopting guidelines based on local susceptibility patterns.