August 12, 2018
Environmentally exposed to antibiotics, leeches carry resistant bacteria to hospitals in their gut. Researchers have discovered that gut bacteria from leeches around the world are gaining resistance to antibiotics present in the environment. In a medical mystery described by Eric Boodman in Stat News, a patient’s skin graft became infected after medicinal leeches were used to reduce venous congestion during surgery. Eventually, the source of the infection was traced to the gut of leeches, where investigators found bacteria resistant to ciprofloxacin. CDDEP Director Ramanan Laxminarayan suggests the finding of resistance in medicinal leech gut bacteria is not surprising and simply one of “a million of these pathways (of resistant bacteria) that come back to bite us.” [Stat News, mBio]
Trace antibiotics may lead to increased environmental antibiotic resistance. Researchers have found that selection for resistance occurs in environments with low levels of antibiotics, and furthermore that the selection level is comparable to environments with high levels of antibiotics. The study looks at varying levels of antibiotics in complex microbial communities. Antibiotics in wastewater samples from the United Kingdom killed many bacterial species while permitting growth of resistant pathogens. The research adds to growing concern about environmentally induced antibiotic resistance. [CIDRAP, mBio]
Transmission of Ebola from female survivor, one year post-recovery. Researchers from the US Centers for Disease Control and Prevention,World Health Organization, and colleagues have published a case study indicating that the Ebola virus can persist undetectable in a female survivor and subsequently reemerge to infect susceptible individuals. In the past, only male survivors were known to transmit Ebola virus, which can remain viable in semen for up to two years. The first such known transmission was investigated by researchers when a teenage boy in Liberia contracted Ebola and died. Serologic, genomic, and epidemiologic findings appear to show that the youth’s mother survived an undiagnosed Ebola infection in 2014. As yet, there is no conclusive evidence explaining the mechanism of transmission. [New York Times, Lancet Infectious Diseases]
Need for a stronger approach to China’s HIV epidemic. In 2017, Premier Li Keqiang pledged to fortify China’s HIV prevention and treatment plan, as epidemiological patterns have changed over time. As attitudes toward premarital sex are changing, the top cause of new HIV infections has shifted from intravenous drug use to sexual transmission, with dramatic increases in young people, especially men who have sex with men (MSM). While China has approved the first low-cost, single pill HIV treatment, sexual education in the country has not adapted to cultural and policy shifts. Inadequate sex education and stigma surrounding at-risk groups may hinder HIV prevention efforts. [The Lancet: Public Health]
Researchers identify gene from Ebola virus in Myotis bats. A multidisciplinary research team has identified a well-preserved, ancient genetic sequence in bat DNA that is similar to a viral gene found in Ebola and Marburg viruses. When these viruses infect an animal, the gene, VP35s, codes for a protein that blocks immune responses, allowing the infection to progress. It is possible the gene functions as an immune regulator in bats, but this hypothesis is unconfirmed. The discovery of the presence of VP35s in bat species could eventually lead to new approaches to Ebola or Marburg vaccine development. [Cell Reports, EurekAlert]
Hyderabad study of community-acquired antimicrobial resistance finds “the poorer the respondent, the higher her risk.” A study of 1,836 women pregnant for the first time shows a “wealth gradient,” with women in lower income brackets found to be infected with antibiotic resistant bacteria at twice the rate of higher income women. Of the women in the sample, 7% had trace amounts of bacteria in their urine; 48% of the women with bacteria in their urine had extended-spectrum beta-lactamase-producing bacteria. Researchers believe the economically-disadvantaged women were exposed to a higher level of antimicrobial drugs from environmental sources. They cite previous studies from Hyderabad showing high levels of antimicrobial drugs in wastewater treatment plants and treatment plant effluents. [Emerging Infectious Diseases, The Hindu]
Trump administration resists WHO antibiotic standards for livestock. The WHO released guidelines in November which called for an end to the ubiquitous practice of giving antibiotics to healthy farm animals. The US Department of Agriculture, however, claims that the report is “not supported by sound science” and plans to write a new set of suggestions for farmers. The new document reportedly would allow farmers to use antibiotics for growth promotion, a practice curtailed by the United States in 2017. [CIDRAP, Bloomberg]
Study results reveal new tuberculosis vaccine candidates. A comparison of two tuberculosis (TB) vaccines has found that revaccination with BCG reduced TB infections by 45.4% in adolescents. Trials involving the investigational vaccine H4:IC31, reduced infections by 30.5%. While not statistically significant, the latter figure shows for the first time that a subunit vaccine may be effective in humans. The study, published in the New England Journal of Medicine, hopes to “inform the development of new tuberculosis vaccines and illustrate the value of conducting human trials of tuberculosis vaccine candidates.” [New England Journal of Medicine, EurekAlert ]
Innovative use of nanoparticle inactivates TB protein. Researchers at the Indian Institute of Chemical Biology (IICB) have found that by attaching a nanoparticle to MPT63, a protein component of Mycobacterium tuberculosis, the molecule became inactive. The innovation contributes to a body of knowledge about the use of bioengineering and nanoparticles in the development of pharmaceuticals. [The Hindu, Langmuir]
Airstrikes in Yemen destroy water facilities, potential cholera outbreak feared. Saudi and Emirati forces carried out airstrikes, damaging water stations in Hodeida that previously supplied water to a majority of the port city’s 600,000 inhabitants. The city serves as a main port for food and supplies to the population of Yemen, approximately 22 million people. Hodeida was also the center of a 2017 cholera outbreak that resulted in over one million suspected cases. The United Nations fears a new outbreak of cholera may follow the recent airstrikes. [Deutsche Welle]
Pharmacists exercise their right to refuse. In several US states including Arizona, Georgia, Idaho, and South Dakota, pharmacists have the legal right to refuse to fill a prescription based on moral grounds. The laws affect patients who would controversial medications such as emergency contraceptives. In states where pharmacies are sparsely located, this can lead to patients traveling long distances for time-sensitive medication, potentially endangering the patient. Pharmacists are not required to report moral conflicts to their employer or to healthcare providers, leading to situations that may cause further patient inconvenience. [Scientific American]
Image Credit: Wikipedia, originally in The Popular Science Monthly, 1880
Original caption:
1. The Medicinal Leech (Hirudo medicinalis) seen from above.
2. The same, under side; a b, sexual organs.
3. The nervous cord with its ramifications: a, forward upper part; b, forward lower part; c, posterior nervous node.
