Carlene A. Muto

COST-EFFECTIVENESS OF PERIRECTAL SURVEILLANCE CULTURES FOR CONTROLLING VANCOMYCIN-RESISTANT ENTEROCOCCUS

BACKGROUNDnSeveral hospitals opting not to use active surveillance cultures to identify carriers of vancomycin-resistant Enterococcus (VRE) have reported that adoption of other parts of the Centers for Disease Control and Prevention guideline for controlling VRE has had little to no impact. Because use of surveillance cultures and contact isolation controlled a large outbreak at this hospital, their costs were estimated for comparison with the excess costs of VRE bacteremias occurring at a higher rate at a hospital not employing these measures.nnnSETTINGnTwo university hospitals.nnnMETHODSnInpatients deemed high risk for VRE acquisition at this hospital underwent weekly perirectal surveillance cultures. Estimated costs of cultures and resulting isolation during a 2-year period were compared with the estimated excess costs of more frequent VRE bacteremias at another hospital of similar size and complexity not using surveillance cultures to control spread throughout the hospital.nnnRESULTSnOf 54,052 patients admitted, 10,400 had perirectal swabs taken. Cultures and isolation cost an estimated

Co-production of NDM-1 and OXA-232 by Klebsiella pneumoniae.

253,099. VRE culture positivity was limited to 193 (0.38%) and VRE bacteremia to 1 (0.002%) as compared with 29 bacteremias at the comparison hospital. The estimated attributable cost of VRE bacteremia at the comparison hospital of

Patient-Associated Risk Factors for Acquisition of Methicillin-Resistant Staphylococcus aureus in a Tertiary Care Hospital

761,320 exceeded the cost of the control program at this hospital by threefold.nnnCONCLUSIONSnThe excess costs of VRE bacteremia may justify the costs of preventive measures. The costs of VRE infections at other body sites, of deaths from untreatable infections, and of dissemination of genes for vancomycin resistance also help to justify the costs of implementing an effective control program.

Why Are Antibiotic-Resistant Nosocomial Infections Spiraling Out of Control?

To the Editor: New Delhi metallo-β-lactamase 1 (NDM-1) and OXA-48-group β-lactamase have been increasingly reported as carbapenemases responsible for carbapenem resistance in Enterobacteriaceae worldwide (1). However, in the United States, Klebsiella pneumoniae carbapenemase (KPC)–type β-lactamase is the most common carbapenemase among Enterobacteriaceae, especially K. pneumoniae. Isolates producing NDM-1 were first reported in the United States in 2010 (2), followed by several case reports and most recently a hospital outbreak in Colorado (3–6). As for OXA-48-group β-lactamase, 2 cases of infection with OXA-48–producing K. pneumoniae were recently reported from Virginia (7). We report K. pneumoniae co-producing NDM-1 and OXA-232, a variant of OXA-48, and Escherichia coli producing NDM-1 that were isolated from the same patient. n nA 69-year-old woman was hospitalized in India for subarachnoid hemorrhage in January 2013. Her hospitalization was complicated by unsuccessful coil embolization and subsequent hydrocephalus. A ventriculoperitoneal shunt was inserted, and she was transferred to an acute care hospital in Pittsburgh, Pennsylvania, USA, for further management in February 2013. She underwent reinsertion of the shunt and was discharged to a long-term care facility (LTCF 1). She was readmitted to the same hospital because of fever in March 2013. n nA urine culture collected at the time of readmission grew carbapenem-resistant K. pneumoniae and extended-spectrum β-lactamase–producing E. coli. Although production of KPC-type β-lactamase was initially suspected in K. pneumoniae, the unusually high level of resistance to amikacin (MIC >32 μg/mL) and gentamicin (MIC >8 μg/mL) increased concern for presence of an NDM-1 producer, which is frequently highly resistant to aminoglycosides because of production of 16S rRNA methyltransferase (8). A modified Hodge test showed a positive result for carbapenemase production, and a metallo-β-lactamase Etest (bioMerieux, Marcy l’Etoile, France) showed a positive result for metallo-β-lactamase production. n nPCR and sequencing identified NDM-1 and OXA-232, a 5-aa variant of OXA-48 recently reported in K. pneumoniae isolates from India (9). Presence of the gene for 16S rRNA methyltransferase (armA) was also confirmed by PCR and sequencing and accounted for the high-level aminoglycoside resistance. The isolate belonged to sequence type (ST) 14, as determined by multilocus sequence typing, and has been reported to be common among NDM-1–producing K. pneumoniae in Europe (10). n nThe patient was discharged to LTCF 1 but was readmitted because of recurrent fever. A urine culture collected at this admission grew carbapenem-resistant K. pneumoniae and carbapenem-resistant E. coli. This E. coli isolate belonged to ST95 and was positive for the NDM-1 gene but negative for the OXA-48 group and armA genes. The original extended-spectrum β-lactamase–producing E. coli isolate belonged to ST3865, which is distinct from ST95. Therefore, it is likely that the patient was already colonized by NDM-1–producing E. coli ST95 at the time of the first admission, but this colonization was not detected in a clinical culture at that time. All K. pneumoniae and E. coli isolates remained susceptible to fosfomycin and colistin. n nThe patient did not receive any antimicrobial drug therapy specific for these isolates because she was deemed to be only colonized with them in the urine. Enhanced contact precautions were also implemented at the time of PCR confirmation of the NDM-1 gene. These precautions included all components of contact precautions (handwashing, gowns, gloves, disinfected/dedicated equipment), and dedicated personnel monitored compliance with these measures around the clock. n nThe patient was eventually discharged to another long-term care facility (LTCF 2) in April 2013. A point surveillance testing for NDM-1–producing Enterobacteriaceae by using rectal swab specimens was conducted for all inpatients at the acute-care hospital and for all residents of the unit at LTCF 2. Testing did not identify any other patients colonized with NDM-1–producing Enterobacteriaceae. n nIn transformation and conjugation experiments, transformants carrying the OXA-232 gene were obtained from K. pneumoniae, but those carrying the NDM-1 gene could not be obtained by either method, suggesting that the 2 genes were not located on the same plasmid. For E. coli, transformants and transconjugants carrying the NDM-1 gene were obtained, which indicated that this gene was located on a self-conjugative plasmid. n nDetection of NDM-1– or OXA-48-group–producing Enterobacteriaceae, in particular K. pneumoniae, poses a diagnostic challenge in regions to which KPC-producing K. pneumoniae is endemic. In our case, recognition of resistance to multiple aminoglycosides by an automated instrument, which was confirmed to be high level by the disk diffusion method (i.e., no inhibition zone), prompted early detection and implementation of appropriate infection prevention measures. Production of 16S rRNA methyltransferase by KPC-producing K. pneumoniae is extremely rare, and no cases have been identified in the United States. Therefore, we propose that high-level resistance to amikacin and gentamicin can serve as a clue for suspecting potential NDM-1–producing isolates in clinical diagnostic laboratories. n nConversely, Enterobacteriaceae producing OXA-48-group carbapenemase, including variants such as OXA-232, do not have characteristic susceptibility patterns and may easily not be recognized in areas with a high background prevalence of KPC-producing organisms. Therefore, organisms producing OXA-48 or their variants might have already spread in the United States.

Economic Analysis of Universal Active Surveillance Screening for Methicillin-Resistant Staphylococcus aureus : Perspective Matters

BACKGROUNDnDetermining risk factors for acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals is important for defining infection-control measures that may lead to fewer hospital-acquired infections.nnnOBJECTIVEnTo determine patient-associated risk factors for acquisition of MRSA in a tertiary care hospital with the goal of identifying modifiable risk factors.nnnMETHODSnA retrospective matched case-control study was performed. Case patients who acquired MRSA during hospitalization and 2 matched control patients were selected among inpatients admitted to target units during the period from 2001 through 2008. The odds of exposure to potential risk factors were compared between case patients and control patients, using matched univariate conditional logistic regression. A single multivariate conditional logistic regression model identifying independent patient-specific risk factors was generated.nnnRESULTSnA total of 451 case patients and 866 control patients were analyzed. Factors positively associated with MRSA acquisition were as follows: target unit stay before index culture; primary diagnosis of respiratory disease, digestive tract disease, injury or trauma, or other diagnosis compared with cardiocirculatory disease; peripheral vascular disease; mechanical ventilation with pneumonia; ventricular shunting or ventriculostomy; and ciprofloxacin use. Factors associated with decreased risk were receipt of a solid-organ transplant and use of penicillins, cephalosporins, rifamycins, daptomycin or linezolid, and proton pump inhibitors.nnnCONCLUSIONnAmong the factors associated with increased risk, few are modifiable. Patients with at-risk conditions could be targeted for intensive surveillance to detect acquisition sooner. The association of MRSA acquisition with target unit exposure argues for rigorous application of hand hygiene, appropriate barriers, environmental control, and strict aseptic technique for all procedures performed on such patients. Our findings support focusing efforts to prevent MRSA transmission and restriction of ciprofloxacin use.

1646Evidence of hospital-associated Clostridium difficile transmission between patients with asymptomatic carriage and patients with Clostridium difficile infection

For as long as the Centers for Disease Control and Prevention (CDC) has measured the prevalence of hospital-acquired infections caused by multidrug-resistant organisms, it has been increasing.1-4 According to the CDC, more than 70% of the bacteria now causing hospitalacquired infections are resistant to at least one of the drugs most commonly used to treat them.5 It seems important to control these infections because they have been more costly and more deadly than those due to antibiotic-susceptible strains of the same species.6-9 Nevertheless, despite decades of discussing the control of antibiotic-resistant nosocomial infections, there has been little evidence of control in most healthcare facilities in most countries.1-3 Several articles in this issue of Infection Control and Hospital Epidemiology evaluate the efforts that have been made by hospitals to control them and may help to explain this failure.10-14 The first of these, by L’Heriteau et al.,10 reports the findings of a nationwide, prospective study designed to describe methods used for diagnosis and surveillance of nosocomial infections and multidrug-resistant organisms in French intensive care units (ICUs). They sought to survey all 573 French ICUs, but only 252 (44%) responded to the written survey. Follow-up telephone interviews of personnel in 143 (47%) of the initially nonresponding ICUs allowed them to increase the overall response rate to 69%. Despite the existence of clearly stated French national guidelines,15 the authors found that there were “profound differences” in the way that ICUs had implemented the recommendations for surveying for various nosocomial infections. They concluded that great caution must be exercised when comparing data regarding ICU infections among French hospitals. Regarding surveillance for multidrug-resistant organisms, they found that 70% of the respondents performed active surveillance cultures to detect these organisms on admission, whereas 60% did so during the stay; 88% of the responding ICUs flagged carriers of multidrug-resistant organisms so that isolation could be maintained consistently. This indicates important variation among hospitals, and inconsistent use of an effective control measure could help to explain difficulties in controlling multidrug-resistant organisms (ie, approximately one-third of the time active surveillance cultures were not being performed to identify contagious patients). A second national survey in this issue of Infection Control and Hospital Epidemiology was designed to examine the extent of implementation of strategies to control multidrug-resistant organisms in U.S. hospitals based on recommendations from a 1994 workshop co-sponsored by the National Foundation for Infectious Diseases and the CDC.16 Ward et al.11 surveyed hospitals for compliance with five goals to optimize antibiotic use and five goals to detect, report, and prevent spread of multidrug-resistant organisms. From approximately 7,000 U.S. hospitals, 108 hospitals (1.5%) were randomly selected to receive a survey (excluding Veterans’ Affairs hospitals and smallto medium-sized teaching hospitals). The survey response rate was 60%. Approximately half of the responding hospitals were classified as large (> 200 beds) and an equal proportion of those remaining as small (50 to 99 beds) and medium (100 to 199 beds). Survey responses were recorded using a 5-point Likert scale. The mean response regarding

A Randomized Crossover Study of Silver-Coated Urinary Catheters in Hospitalized Patients

Infection Control & Hospital Epidemiology / Volume 36 / Issue 01 / January 2015, pp 14 16 DOI: 10.1017/ice.2014.25, Published online: 05 January 2015 Link to this article: http://journals.cambridge.org/abstract_S0899823X14000257 How to cite this article: JaHyun Kang, Kenneth J. Smith, Cindy L. Bryce and Carlene A. Muto (2015). Economic Analysis of Universal Active Surveillance Screening for Methicillin-Resistant Staphylococcus aureus: Perspective Matters. Infection Control & Hospital Epidemiology, 36, pp 14-16 doi:10.1017/ice.2014.25 Request Permissions : Click here

Hand hygiene rates unaffected by installation of dispensers of a rapidly acting hand antiseptic

Background. Despite strategies to reduce transmission, Clostridium difficile (CD) remains a leading cause of morbidity in health care settings. The aims of our study were (1) to determine if asymptomatic inpatient CD carriers can be liked by molecular epidemiology to other inpatients with CD infection (CDI) and (2) to determine if active surveillance testing (AST) criteria to identify inpatients at risk for vancomycin-resistant Enterococcus (VRE) colonization are sufficiently sensitive to capture asymptomatic CD carriage. Methods. Over a 5 day period, all inpatients at University of Pittsburgh Medical Center – Presbyterian Hospital (UPMC) were targeted for one-time AST for CD via perirectal sampling. Archived stool specimens were obtained from (1) clinical CDI cases 7 weeks prior to AST for CD, (2) clinical CDI cases during AST for CD, and (3) clinical hospital-associated CDI (HA-CDI) cases 12 weeks after AST for CD. CD carriage was defined as AST positivity in the absence of clinical CDI during or +/3 months from AST; clinical CDI was defined as clinician-requested, nucleic stool test positivity for toxigenic CD. Specimens were cultured for CD using broth enrichment. CD isolates were typed using tcdC and multilocus variable number tandem repeat (MLVA) genotyping. Isolates whose MLVA genotypes had a summed tandem-repeat difference of ≤2 were considered highly related. “Probable” transmission events were inferred when patients exhibited simultaneous occupancy of the same inpatient ward and their isolates were highly related. “Possible” transmission events were inferred when patients exhibited simultaneous occupancy of the hospital, but not the same inpatient ward, and their isolates were highly related. AST for VRE was performed according to UPMC policy throughout. Results. 53 (10%) inpatients were identified as CD carriers. 123 clinical CDI cases were identified; isolates from 101 (83%) of these episodes were obtained. 6 (5.9%) clinical CDI isolates were highly related to CD carrier isolates, 4 of which were HA and could be linked epidemiologically to CD carriers – 2 by probable and 2 by possible transmission events. None of the CD carriers implicated in transmission events underwent VRE AST. Conclusion. Hospital-wide AST for CD carriage may identify a reservoir of CD involved in CDI. Disclosures. All authors: No reported disclosures.