Superbugs and mere mortals
A conscientious Guyanese agricultural worker, with no known underlying medical issues, suddenly develops an unbearable burning sensation in one dark brown eye. He seeks medical attention and is given antibiotic drops, but the mysterious infection persists and worsens.
Swabs are taken at a private city hospital and tested by laboratory analysts, left puzzled that they cannot identify precisely the origin, what caused the condition and whether it is from a strange fungus or a baffling bacterium. Suggesting a fungal affliction may be behind the obvious corneal ulcer, his doctors eventually recommend that he seek medication, unavailable in Guyana, and alternative expensive treatment overseas at a wellknown specialist.
By the time he arrives in Trinidad and Tobago on emergency leave, weary and worried, two weeks have passed, and his eye is painful, redder and completely clouded. The ophthalmologist scrapes off the diseased cells on the surface of the cornea, the clear, domeshaped multi-layered window which focuses light into the organ, in an initial operation called a superficial keratectomy. Other painful procedures follow to correct the scarring, with a slip of amniotic membrane being grafted to reduce inflammation and trigger growth factors for epithelial wound healing on the surface of the eye, as practitioners struggle to find an elusive antibiotic for full relief and most desirably, a complete cure.
Samples sent to a virologist take several days to be identified and cultured. It is not a fungus but a rodshaped, gram-negative, strictly aerobic bacterium “baddie,” a so-called “red alert” pathogen, Acinetobacter baumannii. In an unprecedented move in 2017, the deeply concerned World Health Organisation (WHO) named the superbug Acinetobacter baumannii as number one in the critical top tier of a deadly three-part priority catalogue of 12 families of bacteria that pose the greatest threat to human health because of their stubborn and alarming multi-drug resistance.
The WHO’s critical trio featuring bacteria Pseudomonas aeruginosa and the Enterobacteriaceae clan are increasingly fighting off the best weapons the world’s mere mortals have to offer, including antibiotics like carbapenems and third generation cephalosporins, once highly effective agents traditionally deployed in the treatment of severe or suspected multidrug-resistant (MDR) bacterial infections.
Divided into two other categories of superbugs according to the urgency of need for fresh antibiotics, the WHO listed the second and third levels as the high and medium priority areas, containing increasingly drug-resistant bacteria that cause more common diseases such as gonorrhoea, and food poisoning from salmonella.
Urging nations to promote and incentivize vital research and development of fresh antibiotics, the WHO warned that mankind is fast running out of treatment options, with a top official pointing out, “If we leave it to market forces alone, the new antibiotics we most urgently need are not going to be developed in time.”
Overprescribing of antibiotics by physicians, the illegal sale of such substances without proper paperwork, the misuse of medicines by patients who fail to complete assigned doses, and the extensive use in livestock have all contributed to the global crisis and terrifying prospects of an ailing world without adequate antibiotics. Linked, too, is the dumping of inadequately treated effluents from the pharmaceutical industry, especially in countries where bulk drugs are manufactured. While more than half of hospitalized patients are likely to get an antibiotic at some point during their stay, studies have shown that between 30-50 percent of those given are unnecessary or incorrect, contributing to widespread antibiotic resistance.
Antibacterial liquids, soaps and hormone disruptive chemicals like triclosan which are added to such products, remain easily available. Back in 2016, the United States (US) Food and Drug Administration (FDA) banned triclosan, triclocarban and 17 other chemicals in consumer products such as hand and body washes, long marketed as better than ordinary soap and water.
Big Pharma is especially reluctant to spend the money needed to develop better drugs, preferring to use their rich resources on medicines for prominent disease cases with greater numbers and media visibility like cancer, that command higher prices and haul in much larger profits. It is estimated that across the globe at least 700,000 to several million deaths result per year because of MDR. Poorer countries such as Guyana with weaker healthcare systems are particularly in peril, meaning that public education about proper use is essential. Simpler measures can be adopted by all, whether health care providers, patients or households starting with proper sanitation and hygiene, such as basic handwashing and disinfecting.
Acinetobacter is a special member of the notorious ESKAPE group. ESKAPE is a popular acronym encompassing the names of the six most insidious bacterial pathogens, the others being Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterobacteriaceae. Appropriately, Acinetobacter baumannii is the “A” in ESKAPE, in reference to the members uncanny ability to outmanoeuvre the effects of the world’s finest antibiotics and doctors, through certain evolutionarily developed mechanisms.
Ironically prevalent in intensive care units and healthcare settings housing very ill patients, the Acinetobacter genus rarely occurs outside these environments, hence it is known as “nosocomial” for its opportunistic ability to latch on to vulnerable cases within hospitals. The term comes from two Greek words, “nosus” for “disease,” and “komeion” meaning “to take care of.”
The genus lists many species or types, all of which can cause diseases ranging from pneumonia and meningitis to blood problems but poses little danger to healthy people. However, those with weakened immune systems, chronic lung disease, or diabetes may be more susceptible to serious infections. Individuals with open wounds or others hospitalised for a long time or on a ventilator are also at greater risk. Yet the long-lived, intriguing Acinetobacter, which is also found in soil and water, may “colonize” or live in some humans without causing sickness or symptoms, the United States-based Centers for Disease Control and Prevention (CDC) advises, noting the peculiar baumannii strain accounts for 80 percent of reported infections.
Colloquially, A. baumannii is referred to as “Iraqibacter” due to its noticeable emergence in military treatment facilities during the Iraq War and it continues to haunt veterans and American Army soldiers who served in that Middle Eastern country and conflict zones like Afghanistan, causing high incidences of MDR bacteraemia or bloodstream infections. According to an article in the “Virulence” Journal, the dry, sandy conditions associated with the desert campaigns provided an ideal environment for the physiologically robust A. baumannii, making it the main source of infection among
injured soldiers. As coalition troops exposed to the bacterium in field hospitals returned home to convalesce for extended stints, the pathogen emerged and strengthened.
“Its pathogenic potential includes the ability to adhere to surfaces, form biofilms, display antimicrobial resistance and acquire genetic material from unrelated genera, making it a versatile and difficult adversary to control and eliminate. The optimal treatment for A. baumannii, especially nosocomial infections resulting from multiple resistant strains, remains to be established. It is thus a clinical imperative that welldesigned procedures are put in place to help guide clinicians on decisions regarding the current best therapeutic practice. Furthermore, new experimental approaches are warranted to develop and evaluate novel therapeutic strategies for dealing with A. baumannii infections,” the Journal said in its 2012 piece.
Acinetobacter was first isolated from soil by a Dutch microbiologist in 1911 with the title coming 43 years later from the Greek “akinetos” meaning non-motile. The genus was widely accepted by 1968 after a University of California, Berkeley team led by P. Baumann published a comprehensive and hallmark study of related organisms, the most famous of which was named in tribute to the expert.
By 2016, US health officials reported the first case in the country of a patient with a “nightmare bacteria” resistant to all known antibiotics. The 49-year-old Pennsylvania woman who had not travelled within the prior five months developed a particularly nasty urinary tract infection, that was immune to the antibiotic of last resort, colistin.
As dedicated scientists step up the battle against MDR strains, there is cause for tentative hope. Just last month, researchers at Washington University School of Medicine studying A. baumannii figured out a key step in the transmission of antibiotic resistance from one bacterium to another, indicating a novel strategy for stopping the spread may be possible in the future.
ID is thankful that her rash-hit husband survived a hospital-induced dangerous attack of the persistent bacterium Pseudomonas aeruginosa, while undergoing extensive treatment in Trinidad, for his third outbreak of dengue fever.