By Carol A. Kemper, MD, FACP

March 1, 2013
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By Carol A. Kemper, MD, FACP, Section Editor: Updates, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases; Santa Clara Valley Medical Center, is Associate Editor for Infectious Disease Alert.

How do infection preventionists know what they know?

Saint S, et al, Perceived strength of evidence supporting best practices to prevent health care-associated infection: results from a national survey of infection prevention personnel. Am J Infect Control 2013;(41):100-106.

In my experience, the success of a good Infection Control program rests on the shoulders of the IC personnel in your hospital. Infection Control staff are the key to communicating, educating, and enforcing good IC practices in the hospital. But, first, the IC staff must appreciate the validity and worth of any particular measure or recommendation. With so much to do in any given day, including surveillance, ward rounds, education, and policy development, how do IC staff prioritize their activities? How these people perceive the merits of any particular recommendation, and where they place their efforts, may significantly impact health care infections in any one hospital.

These authors conducted a written survey of IC staff at 478 non-Federal and VA hospitals in 2009. IC personnel at each hospital were asked to rate their perception of the evidence in support of current IC practices on a scale of 1 to 5 (1 being no evidence and 5 being very strong evidence). The rate of response was 68%. The average infection control experience was 9.6 years.

Ninety percent or more of respondents believed the evidence in favor of the following practices was at least strong to very strong: alcohol based hand gel (97%), chlorhexidine gluconate for skin antisepsis, sterile barriers for catheter insertion, avoiding femeral site for catheter insertion, semi-recumbent positioning for the ventilated patient, and aseptic urinary catheter insertion technique. When asked about particular prevention practices for catheter insertion — often included in a “bundle” — 90% believed the supporting evidence for each of the practices/techniques was strong to very strong. In contrast, the perception of strong supporting evidence for ventilator practices was more varied, ranging from the evidence for semi-recumbent posture (97%), to sedation vacation (88%), antiseptic mouth rinse (68%), subglottic secretion drainage (59%), and silver coated endotracheal tubes (16%).

In reality, the recommendation for semi-recumbant posture is considered a “grade B” recommendation whereas the evidence in support of antiseptic mouth rinse is quite good – a “grade A” recommendation. Those practices which may be well supported by clinical data but not presented in the formal guidelines were perceived by IC staff as weakly supported. And, while recent data indicates that silver-coated endotracheal tubes may result in significantly reductions in VAP, this data was published following publication of the CDC guidelines. In other words, most of the IC preventionists responding to this survey appear to be dependent on how the information is “framed” in a standard guideline or bundle, and not the supporting literature or specific clinical data.

My guess is that the Joint Commission and other regulatory bodies may also emphasize certain practices over others, which can also substantially influence what hospitals and IC personnel are doing. For instance the Joint Commission just queried our staff regarding aseptic insertion technique for Foley catheter insertion – although there is little evidence associating this practice with a reduction in catheter-associated UTIs. In contrast, studies demonstrating less Foley use, with automated reminders or stop dates for Foley use, are significantly associated with lower CAUTI rates.

Other regulatory requirements based on meager supporting evidence may actually detract from other more meaningful infection control efforts. For instance, the California Senate has mandated that hospitals screen high risk admissions for MRSA colonization, and provide counseling to positives — although there are zero public health recommendations or guidelines indicating what to do with this information. But IC personnel are forced to busy themselves educating staff about the importance of this practice, and required by law to focus on 100% successful surveillance as a “quality goal.”

Infection control personnel with certification in infection control (CIC, provided by the Board of Infection Control and Epidemiology) were generally twice as likely to identify good infection control practices as their colleagues without certification. This is strong support for IC personnel continuing education and training, participation in local APIC meetings, and certification in IC within 2 yrs of practice. It might be a good idea to for educational programs to promote an examination of the literature and an understanding of the clinical evidence for why we do things the way we do — not just adherence to a guideline.

Colistin dose and efficacy

Vicari G, et al. Association between colistin dose and microbiologic outcomes in patients with multidrug-resistant gram-negative bacteremia. Clin Infect Dis 2013;56(3):398-404.

Increasingly, we are faced with gram negative rods with broad resistance to antibacterials (MDRGNR) causing serious infection. These authors retrospectively examined the use of parenterally administered colistin in the treatment of MDRGNR bacteremia. Success of treatment at day 7, defined as clearance of bacteremia and survival, was compared with colistin dose. In addition, survival at day 28 and the development of acute kidney injury was examined.

A total of 76 patients received colistin; 52 (68%) of these had clearance of bacteremia by day 7. Colistin dosing was significantly associated with treatment success – patients in the microbiologic success group received a mean daily colistin dose of 2.9 mg/kg (range, 1.7 to 3.68 mg/kg) compared with 1.5 mg/kg for patients in the treatment failure group (range, 1.10-2.0 mg/kg), p = .011. However, one-third of patients (36%) developed acute kidney injury during treatment, which was clearly associated with higher colistin dosage (p < .001). No statistically significant difference was observed in mortality between the two groups at day 28. Colistin sensitivity was performed on 58 patient isolates, all but 2 of which had MIC < 2 mg/dL (two isolates with reduced sensitivity were from patients in the treatment success group).

Catheter related infections were responsible for nearly half of the bacteremias in each group, and the catheter was removed in 33 of 34 cases (one patient in the treatment failure group did not have the catheter removed before death). The number of days from the first positive blood culture to initiation of colistin was similar for both groups (approx. 2.8 days). Concomitant antibiotic use was common in both groups (overall, 71% in the treatment success group vs 75% in the treatment failure group). Concurrent use of carbapenems and aminogylcosides was similar, although tigecycline was used more often in the treatment failure group compared with the treatment success group (54% vs 31%). Other patient characteristics, such as gender, age, and comorbidity index were similar. Patients with microbiologic failure had a higher PITT bacteremia score and a higher frequency of pseudomonas infection compared with those with microbiological success (54% vs 37%). None of these differences were significantly different between groups although, in univariate analysis, PITT bacteremia score and the use of tigecycline were independently associated with treatment failure.

Nationwide shortage of isoniazid

CDC. Notes from the field: National shortage of isoniazid 300 mg tablets. MMWR 2012; 61(50):1029. (2) Health Alert: Nationwide shortage of isoniazid. County of Santa Clara PHD, January 28, 2013.

Beginning in November 2012, states began reporting difficulties in obtaining adequate supplies of isoniazid 300 mg tablets for the prevention and treatment of tuberculosis (TB). This shortage has now spilled over into most states, and we’ve recently had an upsurge in phone calls in our office from patients unable to refill their prescriptions. There are 3 suppliers of INH in the United States: Teva, Sandoz, and VersaPharm. According to the FDA. gov/Drugs/DrugSafety/DrugShortage webpage, the shortage has occurred as the result of increased demand. According to the CDC report above (1), Teva is reporting a shortage because of a delay in receiving its shipment and Sandoz is reporting a shortage of the active ingredient from its supplier. In December, all 3 suppliers reported they should be able to fill orders by December or late January. However, as of the update 02/05/13 on the FDA webpage, drug for Teva remains on back order thru March 2013. The webpage states that additional stock from emergency reserves should, however, be available to meet ongoing demand.

Because of the shortage, the CDC is recommending prioritizing the following for patients with active TB:

  • Identify a local pharmacy(ies) with an adequate supply of drug for your patients;
  • Use INH 100 mg tablets instead of 300 mg tablets
  • Use INH liquid formulation instead of tablets

For patients with latent TB infection, recommendations include (2):

  • Prioritize INH for those at highest risk for reactivation, such as young children, contacts of known TB cases, documented conversion, HIV+, or immune compromised;
  • Consider the use of chemoprophylaxis regimens that use lower amounts of INH, such as weekly INH/rifapentine for 3 months, or twice weekly INH by DOT for 6 months;
  • Consider limiting the use of INH to 6 months, instead of 9 months;
  • Consider limited use of alternative regimens such as rifampin for 4 months.