News Scan for Jun 09, 2017

News brief

Six new asymptomatic hospital MERS cases confirmed in Saudi Arabia

The Saudi Arabian Ministry of Health (MOH) reported six new cases of MERS-CoV today, all linked to one or more of the current hospital outbreaks in Riyadh.

The six patients are all women, all expatriates, and all healthcare workers who contracted MERS-CoV (Middle East respiratory syndrome coronavirus) at work. Their ages ranged from 26 to 48, and they are all in stable condition. None of the women were symptomatic.

Yesterday, the MOH reported five hospital-based cases in Riyadh. So far this month, there have been 27 cases in Riyadh with clear links to hospitals.

The new MERS cases raise the country's total since the outbreak began in 2012 to 1,630, including 671 deaths. Eleven patients are still receiving treatment.
Jun 9 MOH report

Review shows weaker measles immune response with earlier vaccination

Receiving measles vaccine earlier in infancy may be related to a poorer immune response compared with receiving it a bit later, findings that support US vaccine schedules, according to a meta-analysis published yesterday in Clinical Infectious Diseases.

Canadian investigators identified five randomized, controlled trials involving 5,542 children who were given the first dose of measles vaccine when they were 11 months to 22 months old. Four studies involved the tetravalent MMVR (measles-mumps-rubella-varicella) vaccine in 13 European countries in 2004 through 2008, while the other involved the trivalent MMV (measles-mumps-rubella) vaccine in the United States from 2010 to 2012.

The researchers found that, when they divided children by month of vaccination (11, 12, 13-14, and 15-22), the percentage of vaccine recipients testing seronegative for measles 6 weeks post-vaccination was 8.5%, 3.2%, 2.4%, and 1.5%, respectively.

Except for certain high-risk groups, the US Centers for Disease Control and Prevention recommends a first dose of MMR at 12 months through 15 months. A second dose should be given at 4 through 6 years of age, but it can be given earlier if at least 28 days have passed since the first dose.

The immune response to the vaccine, measured in geometric mean concentration (GMC), showed a similar pattern to the rates of seronegativity. The GMC varied from 1,835 milli-international units per milliliter (mIU/mL) in the youngest-vaccinated group to 3,562 mIU/mL in the oldest-vaccinated. The MMVR vaccine produced a stronger immune response across all groups. GMC for MMVR ranged from 2,051 to 4,199 mIU/ML, whereas GMC for MMR ranged from 1,188 to 2,751.

The authors noted that these effects persisted even after children received the second vaccine dose.
Jun 8 Clin Infect Dis study

Cholera cases in Yemen top 100,000

The World Health Organization (WHO) said today that cholera cases in Yemen have climbed past the 100,000 mark. As of Jun 7, there were 101,820 cases and 791 deaths reported.

According to the WHO, children younger than 15 account for 46% of the cases, and those 60 years old and older represent 33% of fatalities. Transmission is occurring in "cholera hot spots," conflict zones populated with displaced people.

Nearly half the hospitals in Yemen have closed in the last 2 years during conflict, and 4.5 million people do not have regular access to clean water and sanitation. The WHO said health and sanitation workers have not received their salaries in more than 8 months.

At least $66.7 million is needed over the next 6 months to establish oral hydration stations, provide chlorinated drinking water, and rebuild sanitation infrastructure, the agency said.
Jun 8 WHO press release

ASP Scan (Weekly) for Jun 09, 2017

News brief

Our weekly wrap-up of antimicrobial stewardship & antimicrobial resistance scans

Piperacillin-tazobactam shows promise for treating ESBL UTI

Originally published by CIDRAP News Jun 8

A study yesterday in BMC Infectious Diseases indicates that piperacillin/tazobactam (PTZ) is effective in treating healthcare-associated urinary tract infection (UTI) caused by extended-spectrum, beta-lactamase-producing Escherichia coli (ESBL-EC), a type of infection for which therapeutic options are limited.

In the first randomized study comparing the efficacy of PTZ, ertapenem, and cefepime against nosocomial ESBL-EC UTI, researchers evaluated 72 patients across three Korean hospitals between January 2013 and August 2015. Six patients received cefepime therapy, while 33 patients each were randomized to the PTZ and ertapenem groups. Researchers identified ESBL-EC as the sole cause of UTI in each case patient and determined antibiotic susceptibility prior to treatment.

Treatment success, defined as cessation of symptoms and a negative urine culture, occurred in 93.9% of patients receiving PTZ and 97% of those treated with ertapenem. The cefepime treatment arm of the study was stopped after investigators observed a low treatment success rate (33.3%), along with two deaths related to treatment failure and septic shock.

Mortality rates 28 days following treatment were similar in the PTZ and ertapenem group (6.1% each) and were associated with septic shock.

The investigators wrote that empiric PTZ therapy for healthcare-associated ESBL-EC UTI is reasonable when testing indicates susceptibility to the antibiotic, also cautioning that "cefepime should not be used as an alternative treatment in urinary tract infections caused by ESBL-EC."
Jun 7BMC Infect Dis study

Study says livestock environment key factor in MDR Salmonella

Originally published by CIDRAP News Jun 8

In a study involving multidrug-resistant (MDR) Salmonella in food animals, researchers from the University of Minnesota found that environmental factors, and not the genetic background of the pathogens, are the strongest predictors for the acquisition and spread of MDR strains.

Writing in PLoS One, the investigators said they collected 80 MDR Salmonella isolates each from cattle, swine, and poultry in 5, 14, and 1 state, respectively, with the poultry isolates from Minnesota. The isolates showed distinct MDR patterns among the three animal types, as shown in the table below. Notably, all 240 isolates were resistant to macrolides, but only 11—all from pigs—were resistant to fluoroquinolones.

Using an evolutionary analysis called STRUCTURE, the researchers determined that the livestock environment, and not the genetic background of different Salmonella subtypes, was the strongest determining factor for acquisition and spread of MDR strains. The team also described a new mutation linked to fluoroquinolone resistance.

The authors conclude, "These findings imply that each livestock environment (i.e., avian, bovine, and porcine) has a unique set of selective pressures that cause the acquisition and spread of distinct antimicrobial resistant genes in [Salmonella] associated with that environment." They add that selective pressures have been working on the bacteria for a long period.
Jun 7 PLoS One study

Vancomycin taper-and-pulse dosing may help cure recurrent C diff

Originally published by CIDRAP News Jun 8

Oral vancomycin taper-and-pulse (VAN-TP) dosing techniques were associated with a 74% cure rate overall in patients with recurrent Clostridium difficile infections (rCDI), according to a study published yesterday in Clinical Infectious Diseases.

Though the Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of American recommend VAN-TP for treating rCDI, few studies have determined optimal regimens and outcomes. To address this gap, researchers associated with Loyola University Medical Center and Merck & Co. conducted a retrospective chart review of 100 patients receiving oral VAN-TP at a single center from Jan 1, 2009, to Dec 31, 2014.

Patients had experienced an average of three prior CDI episodes at the time of treatment. Therapy followed IDSA VAN-TP guidelines for rCDI, which recommend oral vancomcin tapered to once daily for 7 days following a standard course of treatment, after which the dose is "pulsed" by administering it every 2 (QOD) or 3 (Q3D) days.

Among the 64 patients receiving VAN-TP with a QOD-followed-by-a-Q3D pulse for at least 2 weeks, 52 (81.3%) were cured, compared with 22 of 36 (61.1%) of patients receiving a taper and QOD pulse only. Average treatment time length was longer for patients in the QOD-plus-Q3D group than for QOD patients (86.3 versus 60.3 days). Recurrence of diarrhea requiring re-treatment occurred in 26% of patients overall.

"VAN-TP with careful follow-up can be a very effective treatment strategy for patients with rCDI," the authors write, adding that "longer treatment courses do not necessarily translate into better cure rates."
Jun 7 Clin Infect Dis study

Pharmacist-driven ASPs tied to fewer deaths, better antimicrobial use

Originally published by CIDRAP News Jun 6

A pharmacist-driven antimicrobial stewardship program (ASP) in intensive care units (ICUs) in eastern China was associated with decreased mortality, lowered emergence of multidrug resistance, and optimized use of antimicrobial agents, according to a study yesterday in the American Journal of Infection Control.

Researchers from Hangzhou analyzed data from 577 patients in multiple ICUs, 353 of whom were involved in a pharmacist-driven ASP. The primary outcome was all-cause hospital mortality.

The pharmacist-directed ASP was associated with a 19.3% hospital mortality rate, compared with 29.0% for other ASPs. In addition, the pharmacist-driven strategy was tied to a shorter duration of empirical antimicrobial therapy (2.7 days vs 3.0 days) and a 1-day shorter accumulated duration of antimicrobial treatment.
Jun 5 Am J Infect Control study

Lactobacillus isolate from yogurt shows promise against resistant bacteria

Originally published by CIDRAP News Jun 6

A Lactobacillus isolate from yogurt, called Lactobacillus parafarraginis, inhibited the growth of several multidrug-resistant (MDR)/extended spectrum beta-lactamase (ESBL) bacteria from patients at a hospital in Washington, D.C., according to preliminary data presented at the ASM (American Society of Microbiology) Microbe meeting that wrapped up yesterday.

Researchers from Howard University screened 68 lactic acid bacteria isolated from commercial yogurt and cheese for antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes,and Escherichia coli O157:H7. Although 93% showed antimicrobial activity against the pathogens, they identified an L paragarraginis isolate as showing high potential against resistant bacteria.

When tested in the lab, the bacterium inhibited 14 MDR and ESBL bacteria from clinical sources: E coli (5 isolates), Pseudomonas aeruginosa (2), Acinetobacter baumannii/haemolyticus (3), Enterobacter aerogenes (1), Proteus mirabilis (2),and Klebsiella pneumoniae (1).

"Considering the current upsurge of antibiotic resistance in hospitals, especially among the gram-negative bacteria, and the exigent need to find viable alternatives, findings from the study may hold promise for possible therapeutic application," said lead author Rachelle Allen-McFarlane, Howard University doctoral candidate in biology, in an ASM press release.
Jun 2 ASM Microbe abstract
Jun 2 ASM news release

MSSA study finds more evidence for emerging genotype, spread from NYC

Originally published by CIDRAP News Jun 6

A retrospective analysis of 34,025 methicillin-susceptible Staphylococcus aureus (MSSA) isolates collected at 136 Veterans Administration (VA) medical centers between 2003 and 2014 suggests that an emerging genotype resistant to commonly used antibiotics is increasingly implicated in invasive infections and is diffusing outward from New York City.

A team based at the University of Iowa published its findings yesterday in Antimicrobial Resistance and Infection Control. They used resistance to clindamycin and erythromycin, but susceptibility to tetracycline, as a cost-effective proxy for genotype analysis to track patterns with the ST398 genotype, which emerged in New York City.

They found that 4,582 (13.5%) isolates met the definition of ST398. When they gauged the proportions of ST398 by hospital and compared facility distance from New York City, they found that levels increased nearly three-fold over the 12-year period, but it wasn't evenly distributed: It diffused outward from the city.

Though the definition they used doesn't definitively signal that the MSSA infections were caused by ST398, the spatiotemporal patterns seen in the resistance pattern suggest it, the group wrote. The rise of ST398 in New York City VA hospitals and diffusion to facilities in other parts of the country is consistent with earlier reports of the city as the source as well as with the patterns seen at hospitals that aren't part of the VA system.

The spread of ST398, thought to be easily transmissible among humans, would be worrisome, because ST398 may be more fit and virulent in both its MSSA and methicillin-resistant forms, and clindamycin resistance has important clinical implications.
Jun 5 Antimicrob Resist Infect Control abstract

MDR Pseudomonas infections nearly twice as deadly for hospital patients

Originally published by CIDRAP News Jun 5

A review of hospital-onset Pseudomonas aeruginosa infections in the United States found that the mortality from multidrug-resistant P aeruginosa (MDR-PSA) is nearly twice that of non-MDR-PSA infections.

For the study, which was presented at ASM Microbe 2017, which ended today, researchers used an electronic research dataset that includes microbiology/general lab results, pharmacy orders, and financial data to identify PSA isolates from blood, wound, urine, respiratory tract, gastrointestinal tract, and other sources collected at US hospitals from January 2013 to September 2015. Isolates were labeled as hospital-onset if they were collected more than 3 days after admission or through 1 day after discharge. The researchers then compared the mortality and hospital length of stay associated with MDR-PSA versus non-MDR-PSA infections.

Of 4,522 cases, 3,643 (80.6%) were non-MDR and 879 (19.4%) were MDR-PSA. Isolates recovered from respiratory sources accounted for 42.4% of all MDR cases, followed by urine (33.1%), and wound (18.3%). While the overall mortality for all PSA infections was 12.8%, the researchers found that mortality was 19.8% for patients with MDR-PSA infections, compared with 11.1% for patients with non-MDR PSA infections. In addition, patients with MDR-PSA were in the hospital for 14.3 days longer than patients with non-MDR-PSA.

Study co-author Sanjay Merchant, PhD, executive director of the Center for Observational and Real World Evidence at Merck & Co., told Infectious Disease News that the findings highlight the need for effective therapy against MDR PSA infections.

"Additionally, hospitals should consider utilizing various infection management strategies, including hand hygiene, environment cleaning and increasing heterogeneity of antibiotic prescribing, to minimize the emergence and spread of MDR-PSA resistance in hospitals," he said.
Jun 3 ASM 2017 abstract (#5262, pg. 566)
Jun 4 Infectious Disease News article

Study evaluates alternative disinfectants for C difficile

Originally published by CIDRAP News Jun 5

A new study by Dutch researchers in Antimicrobial Resistance & Infection Control indicates that Clostridium difficile spores of PCR ribotypes 014 and 027 strains are harder to eradicate than non-toxigenic PCR ribotype 010.

The researchers were testing four different products commonly used for cleaning and disinfecting in Dutch hospitals for their efficacy against C difficile, the most common source of healthcare-associated diarrhea and a growing threat associated with morbidity, mortality, and extra costs. The four different compounds, potential alternatives to liquid bleach (the main disinfectant used against C difficile), included:

Hydrogen peroxide 1.5%
Glucoprotamin 1.5%
A mixture of ethanol, propane, and N-alkyl amino propyl glycine
A mixture of didecyldimonium chloride, benzalkonium chloride, polyaminopropyl, biguanide and dimenthicone as active ingredients

The products, in wipe and spray form, were tested against ceramic tiles contaminated with an outbreak-related PCR ribotype (027), an endemic PCR ribotype (014), and a non-toxigenic ribotype (010). C difficile 014 is the most prevalent PCR ribotype in the Netherlands. The effectiveness was measured in reduction of colony-forming units (CFUs).

Regardless of the disinfection method, the overall CFU reduction was highest for C difficile PCR 010, followed by 014 and 027. In general, the ready-to-use wipes performed better than the sprays for all compounds, with hydrogen peroxide wipes showing the highest bactericidal activity.

"Ready-to-use wipes eliminate the possibility of human errors that could make the disinfectant less effective or make the wipes unnecessarily toxic," the authors write.

The authors say the findings indicate "the importance of including a variety of clinically relevant ribotypes when evaluating the effects of disinfectants against C difficile."
Jun 3 Antimicrob Resist Infect Control study