In 2010, an estimated seven per cent of people starting antiretroviral therapy (ART) in developing countries had drug-resistant HIV.
In developed countries, the same figure stood at 10–20 per cent. Some countries have recently reported levels at or above 15 per cent amongst those starting HIV treatment, and up to 40 per cent among people re-starting treatment according to a World Health Organisation Report.
In Kenya, studies show that there has been increasing cases of drug-resistant HIV. For instance, at least one in 10 people in Homa Bay county who is HIV-positive has a strain that is resistant to at least one of the available antiretrovirals, even when he or she has never been put on any HIV/Aids treatment.
Once treated with isoniazid and rifampicin for six months, resistance has emerged not only to these medicines, but to the wider range of other drugs.
This has led to the emergence of Multi-Drug- Resistant TB (MDR-TB), the less treatable Extensively Drug-resistant TB (XDR-TB), and even to total drug-resistant TB, which has officially been confirmed in India. Resistance to TB has reached a global scale with XDR-TB now reported in 92 countries.
The disease is caused by a fast-learning, quickly-evolving bacterium salmonella typhi, that has developed defenses against drugs.
Typhoid has, therefore, shown increasing resistance to fluoroquinolones, the preferred antibiotic for treating multidrug-resistant typhoid since the 1990s, and to some third-generation cephalosporins, which are costly.
Once fixable with penicillin and tetracycline, however, the bacteria that causes the disease has developed such high levels of resistance that there is only one drug left that can treat it.
Even this antibiotic, ceftriaxone, is becoming less effective. Actually strains of multidrug-resistant gonorrhea that do not respond to any available antibiotics have already been detected.
5. Candida auris
Candida auris, is a yeast that normally lives harmlessly on the skin and mucous membranes. This yeast was first discovered in 2009 from the ear discharge of a patient in Japan.
Most strains of C. auris are resistant to at least one antifungal drug class, according to US Centre for Disease Control and Prevention and more than one-third of the strains are resistant to two. A subset of strains is resistant to all three antifungal drug classes available.
Malaria is caused by a parasite that is transferred to humans through mosquito bites. The discovery of Chloroquine (CQ) in the 1930s revolutionised malaria treatments.
CQ was the most widely-used drug from the early 1950s to until the 1990s. However, mutations within Plasmodium falciparum, the parasite that causes the mosquito-borne disease, which conferred resistance to CQ arose independently in Columbia and Thailand.
Since then, CQ-resistant mutations have been spreading quickly through most endemic areas. Later, Sulfadoxine-pyrimethamine (SP), a combination of two drugs, replaced CQ.
However, resistance to SP evolved rapidly and now occurs at high frequency in major malaria regions.
According to studies, there are five different parasites that can cause malaria and three of those parasites have now developed resistance to antimalarial drugs.
Streptococcus pneumoniae (S pneumoniae) bacteria, which causes pneumonia, meningitis, sepsis, and otitis media has developed increased resistance to multiple classes of antibiotics.
S pneumoniae resistance to penicillin was first reported with subsequent development of resistance to other classes of drugs. Recent data shows there are high rates of penicillin resistance among S pneumoniae in France and Spain, with intermediate and resistant strains currently accounting for 50 per cent of isolates.
Known for at least 500 years, syphilis was the cause of a pandemic that started at the end of the 15th century. Syphilis is a bacterium most commonly spread through sexual contact.
In August 2016, World Health Organisation released new treatment guidelines for gonorrhoea, syphilis, and chlamydia, noting that all three infections are showing increasing signs of multi-drug resistance.
Syphilis displays resistance to azithromycin, the antibiotic that is the second drug of choice for treating its infection.
Drug resistant strains have not become common yet, but the WHO report warns that this is a growing problem in many parts of the world.
Cholera is an acute intestinal infection caused by Vibrio cholera. However, a new strain of Cholera has been discovered in Kenya for the first time.
According to research findings by the Kenya Medical Research Institute (Kemri), the Cholera strain is drug resistant and is different from others reported in Africa.
The strain, vibrio cholerae inaba, has acquired a resistant characteristic called extended-spectrum beta-lactamases (ESBL).
It is suspected to have hatched in the Indian sub-continent and was first detected in Kenya in 2015 at the Daadab refugee camp.
Infection with herpes viruses can cause sores and in some cases, ulcers in the mouths and genitals. These sores can usually be treated with drugs, but cases of herpes that are resistant to drugs are increasingly leaving doctors and their patients with few options.
The good thing is that a group of doctors in New York recently reported the case of a person with Aids who successfully recovered from drug-resistant herpes when he was treated with Aldara (imiquimod), an immune booster.