Updates

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

Opportunity for Antimicrobial Stewardship

Source: Jenkins TC, et al. Skin and soft tissue infections requiring hospitalization at an academic medical center: Opportunities for antimicrobial stewardship. Clin Infect Dis. 2010;51:895-903.

These authors examined the use of antimicrobials for skin and soft tissue infection (SSTI), comparing the presentation, complications, microbial results and outcomes of adults hospitalized at Denver Health Medical Center. Cases were identified based on discharge diagnosis and ICD-9 codes. Organisms found in culture from a deep-tissue specimen, aspirate or blood were considered pathogens.

A total of 404 patients with SSTI were identified; 81 were excluded for various reasons (refusal of care, odontogenic infection, etc.), leaving a total of 332 evaluable patients. Of these 66 (20%) had cellulitis, 103 (32%) had cutaneous abscess and 153 (48%) had complicated SSTI (which included deeper infection at or below the fascial plane, bacteremia, sepsis, diabetic ulcer or chronic ulcer, human or animal bite, recent hospitalization, or surgical-wound infection). Diabetes, alcohol use, and injection drug use was common.

Staphylococcus aureus and Streptococcus spp. were present in 97% of cutaneous abscess and in 96% of complicated SSTI. Additional bacteria were present in some of these, including anaerobes in 17% of cutaneous abscesses and 22% of complicated SSTI, and aerobic gram-negative rods in 13% of cutaneous abscesses and 14% of complicated SSTI. Therefore, only S. aureus and/or Streptococcus spp. were isolated in 77% and 71% of cases, respectively. Approximately two-thirds of the S. aureus in culture were methicillin-resistant.

All of the patients received parenteral therapy. Broad-spectrum antimicrobials were employed for most of the cases, especially during the first 3 days. Vancomycin was the most frequently used agent (73% of cutaneous abscesses and 79% of complicated SSTI infection); the median duration of use was 3 days. Agents with broad gram-negative activity were used in 61% and 80% of cutaneous abscess and complicated SSTI, respectively, for a median of 3 days. And, agents with anaerobic activity were used in 73% and 83%, respectively, for a median of 3 and 4 days. Three or more antibiotics were used in 40% and 48% of these cases, respectively. The average duration of therapy for cellulitis, cutaneous abscess, and complicated SSTI was 13, 13, and 14 days, respectively.

Radiographic studies were performed in 20% of patients, with a resulting low yield. Only 2% of cases undergoing CT and 1% of cases undergoing MRI, yielding meaningful information.

Based on the culture results, the authors concluded that most of the antibacterial therapy used for SSTI was unwarranted, especially considering that 52% of the cases in this study were uncomplicated cellulitis and cutaneous abscess, providing a perfect target for education and antimicrobial stewardship. Several studies suggest that the duration of total antibacterial therapy can also be safely reduced in most of these patients.

Antimicrobial Effects of Citrus in Food

Source: Herrara A, et al. The effect of preparation of cebiche on the survival of enterotoxigenic Escherichia coli, Aeromonas hydrophila, and Vibrio parahaemolyticus. J Travel Med. 2010;17: 395-399.

Cebiche is a common latin american dish made of raw fish and vegetables, marinated with lime juice. It is a commonly held belief, not especially evidenced-based, that the acidic nature of the citrus destroys any bacteria present in the raw food, rendering it safe to eat. In fact, the opposite may be true. One Mexican study found that 16% of cebiche samples surveyed contained Salmonella spp.

The United States Naval Medical Research Department examined the bacteriocidal effect of lime juice on bacterial colony counts in cebiche, inoculated with infectious doses of either enterotoxigenic Escherichia coli (ETEC), Aeromonas hydrophila, or Vibrio parahaemolyticus. First, the Naval researchers whipped up a batch of a familiar Peruvian cebiche recipe containing cilantro, garlic, hot peppers, sweet potato, corn, and fresh lime juice. They next took a local coastal fish, called Toyo, purchased fresh from the supermarket, and marinated it with 50 mL bacterial suspensions containing 1 x 108 CFU/mL of the three bacteria, and let stand for 10 minutes. The fish medley was then combined with the vegetables, and the pH and bacterial colony counts were tracked for 30 minutes.

The baseline pH of the fish without the lime juice was 6.5. Immediately after combining with the lime juice-vegetable medley, the pH fell to 5.0, but rose to 5.2 and 5.4 over the next 10 to 30 minutes. Homogenates of the mixture yielded lower bacterial colony counts within the first 10 minutes (with an approximate half log drop from baseline), but bacterial counts remained well above the infectious dose of bacteria. After 10 minutes, bacterial growth for both A. hydrophila and ETEC appeared to recover and, by 30 minutes, approached the baseline inocula.

The addition of lime juice to this common Peruvian cebiche dish, spiked with pathogenic bacteria, did not appreciably reduce bacterial colony counts.

Alcohol Hand Gel in Schools

Source: Prazuck T, et al. Reducing gastroenteritis occurrence and their consequences in elementary schools with alcohol-based hand sanitizers. Pediatr Infect Dis J. 2010;29:994-998.

At our new hospital in mountain View, California, rates of hand cleansing have improved to > 95% with the installation of a hand-gel dispenser at the doorway of every patient room (Gel in! Gel out!). Coupled with an employee contest to promote hand cleansing among hospital staff (win a videocam!), hand cleansing has finally become habit. Alcohol-based hand gels have now made it into other areas of our lives, including schools, homes, and I've even seen bridge players (mostly ladies) pull tiny Purell bottles out of their purses during tournaments, when duplicate boards are passed around to multiple tables (those dirty cards).

These authors examined whether the use of alcohol-based hand gels in primary school reduces the risk of gastrointestinal illness in children during the epidemic season. Children at one school were schooled in the use of hand gel throughout the day for 17 weeks; children at a second school did not use hand gel and served as controls. The authors state that use of hand sanitizers was "under strict teacher supervision" (spare the rod, but not the hand gel). Weekly surveys of the children assessed rates of reported illness, absenteeism, doctor visits, and missed days of work by parents.

A total of 476 children participated in the project, returning 4,654 weekly surveys. One-hundred and fifty-five children (36%) developed at least one episode of gastroenteritis. Children in the intervention group were significantly less likely than control children to develop gastroenteritis (24.7% vs. 41.9%, c2 = 16.4, p < .0001). A 41% reduction in the average number of gastroenteritis episodes was observed in the school using alcohol-based hand gel compared with the control school (p < .001).

Alcohol-based hand gel appears to be a simple and inexpensive intervention in reducing rates of infectious gastroenteritis children in elementary schools.

Reality TV Uncovers the Dirt

Source: Hintikka A, et al. The reality of hand hygiene compliance in two Finnish hospitals based on watching and analyzing two hospital reality televion series. J Infect (letter); 2010 (e- release, avail. at www.sciencedirect.com).

Two hospital-based reality tv shows from Finland provided an opportunity to watch hospital employees in action and observe their compliance with hand hygiene and other infection control practices. The two prime-time TV shows aired in 2008, totaling 60 thirty-minute segments, and tracked the day-to-day activities of hospital staff at two Helsinki hospitals. One investigator watched all 60 episodes (hopefully he TiVo'ed).

A total of 142 hand hygiene opportunities were observed (approximately 2.3 patient care contacts per 30 minute segment). Despite the fact that hospital employees knew they were being filmed, alcohol-based hand gel was used appropriately for only 19% of these. In one scene, a hospital employee dried his hands on patient bedding.

Gloves were used 206 times – but nearly half of this (46%) was inappropriate overuse, and not once were hands cleansed before or after donning gloves, as per hospital policy. Gloves were also commonly used for multiple tasks without being removed. The investigators report that it was common for employees to scratch their head with a gloved hand. Mostly, gloves were used for patient transport, patient contact not requiring gloves, and during radiographic procedures, suggesting that employees used gloves when they perceived there was a risk to themselves, and not to protect patients. In addition, the investigators observed numerous other violations of hospital IC policies, including frequent food at the nursing stations, placing charts on patient beds, and artificial nails.

Hospital Infection Control staff at the two hospitals were understandably dismayed by these findings. In a final episode, a special segment devoted to improved hand hygiene and other infection control measures was aired. Now if only life was a bit like reality TV!