Stewardship / Resistance Scan for Jun 08, 2017

News brief

Piperacillin-tazobactam shows promise for treating ESBL UTI

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

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

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

News Scan for Jun 08, 2017

News brief

WHO, GPEI confirm 3 cases of vaccine-derived polio in Syria

The World Health Organization (WHO) and the Global Polio Eradication Initiative (GPEI) confirmed today that there are at least three children with circulating vaccine-derived poliovirus type 2 in the Deir-Ez-Zor governorate of Syria. Two children have developed acute flaccid paralysis (AFP), and one child has tested positive for the virus but is currently healthy.

Genetic analysis of the viruses showed that they were related and circulating in that region of Syria for approximately 2 years.

The Deir-Ez-Zor governorate is a conflict zone in Syria, and several previous polio vaccination campaigns have been unsuccessful in the past. The current campaign began in March and April using the bivalent oral polio vaccine (OPV).

Despite limited coverage, the GPEI said that the detection of three cases of polio show that disease surveillance systems are functional in Syria.

In the middle of May, ProMED Mail, based on a report from an anonymous source, said health officials were investigating a cluster of 23 AFP cases in Syria in the same governorate. ProMED Mail is online reporting system of the International Society for Infectious Diseases.
Jun 8 GPEI statement
May 15 CIDRAP News scan "Investigators probe acute flaccid paralysis cluster in Syria"

Study: Healthcare workers ill-prepared for Ebola in Ghana

A new study published in the journal BMC Public Health said that of 101 healthcare workers (HCWs) questioned in Ghana, 91% said they were not adequately prepared to handle a suspected case of Ebola.

The study is published as the Democratic Republic of the Congo is responding to that country's eighth outbreak of the deadly hemorrhagic fever. To date, there have been no cases of Ebola reported in Ghana, but the country was at risk during the 2013-2015 outbreak in West Africa.

Researchers conducted face-to-face interviews with HCWs at two different health facilities in Ghana and based their preparedness questions on the WHO's Ebola Preparedness Checklist.

Ninety-two of the 101 HCWs questioned said they had not had training to handle Ebola cases. Only 26 (25.7%) said their places of employment were equipped to handle Ebola, and only 9 correctly identified which disinfectant to use while caring for a patient with suspected Ebola.
Jun 6 BMC Pub Health study

Babies contract Legionnaires' disease after water birth

Arizona health officials and experts from the US Centers for Disease Control and Prevention (CDC) today described two Legionnaires' disease cases in newborns after water births.

Both occurred in Arizona during the first half of 2016, and both babies were born at home with different midwives assisting. The researchers described the cases in the latest edition of Morbidity and Mortality Weekly Report (MMWR). Details on the two cases come 2 day after CDC officials raised concerns about infections from Legionella bacteria in health settings.

One of the babies was delivered in a newly purchased disposable tub that had been filled right before birth with municipal tap water from a new hose. The next day the infant was hospitalized with respiratory distress and congenital heart disease. The other was delivered in a rented Jacuzzi that was filled with municipal tap water with a new hose about a week before birth. Three days after birth, the baby had a fever and was seen at the emergency department, where radiographs showed suspected pneumonia.

Lab tests in both instances were positive for Legionella infection, but the specimens were from different serotypes. Both babies were treated with a 10-day course of azithromycin and recovered from their infections.

Investigations afterward found gaps in infection prevention for water births, especially for the second case. The researchers noted that tap water is not sterile and that Legionella can grow and spread in human-made water systems, including in plumbing.
Jun 8 MMWR report
Jun 6 CIDRAP News story "CDC: Most healthcare-acquired Legionnaires' cases could be prevented"