Nav: Home

Antibiotics against severe salmonella infections in Africa increasingly ineffective

June 14, 2016

"The affected countries will have a major problem if we do not manage to control salmonella bloodstream infections with new antibiotics such as ciprofloxacin," cautions Prof Jürgen May. He has conducted numerous studies on salmonella infections in sub-Saharan Africa, particularly in Kumasi in Ghana, where the Bernhard Nocht Institute and the DZIF are in close partnership with researchers from the Kumasi Centre for Collaborative Research in Tropical Medicine.

Nowadays, bloodstream infections with the salmonella species Salmonella enterica are a particular problem in developing countries; infections of the gut occur through contaminated food and unclean water. Annually, approximately 22 million people contract typhoid fever, which is probably the best known infection caused by salmonella. They are specifically caused by Salmonella Typhi bacteria, a Salmonella enterica serotype. Symptoms of typhoid fever include fever, stomach ache and bowel obstruction, and the infection can be fatal if left untreated. Additionally, so-called non-typhoid salmonella infections exist which are caused by other Salmonella enterica serotypes. They also cause bloodstream infections, affecting a further estimated 90 million people per year. It is not known why the pathogen so often enters the bloodstream in these countries. A simultaneous malaria infection seems to be a facilitating factor.

Since the early 1990ies, multidrug-resistant salmonella strains that are insensitive to commonly used antibiotics like ampicillin and chloramphenicol have been emerging more and more frequently. Consequently, the WHO recommended using third generation antibiotics, such as ciprofloxacin from the fluoroquinolone group. In a study in Ghana, May and his team investigated whether this new antibiotic now also triggers the development of resistance. From 2007 to 2012, over 300 isolates of invasive salmonella were collected from blood cultures, i.e. those that cause bloodstream infections.

The results from the study are a first warning sign: reduced susceptibility to ciprofloxacin was found in some salmonella serotypes; in one serotype, even half of the isolates were affected. Isolates of Salmonella Typhi, the pathogen that causes typhoid fever, did not show reduced susceptibility. However, in a multicountry analysis, Salmonella Typhi has already been found to have reduced sensitivity to ciprofloxacin; this being particularly high in Kenya. "This is worrying because ciprofloxacin is going to be used more frequently with decreasing costs," explains May.

Furthermore, the scientists have detected single mutations in the pathogen's hereditary information which are responsible for the reduced sensitivity.

"These results highlight that the emergence of multidrug-resistant salmonella strains must be observed carefully in order to control the burden of neglected diseases such as typhoid fever and non-typhoid salmonella infections," May emphasizes. "An important step to improving the situation has been establishing the Typhoid Fever Surveillance in Africa Program (TSAP), a multinational research programme which, together with the DZIF, collected the data in sub-Saharan Africa." In this programme, May and other scientists also conducted studies on hygiene measures, pathogen spread, vaccines and diagnostics. The studies are published in the current Clinical Infectious Diseases journal supplement.
-end-
Publications

Eibach D et al: The Emergence of reduced Ciprofloxacin Susceptibility in Salmonella enterica causing Bloodstream Infections in rural Ghana
CID 2016, 62(S1); 32-36.

Al-Emran HM et al: A Multicountry molecular Analysis of Salmonella enterica Serovar Typhi with reduced susceptibility to Ciprofloxacin in Sub-Saharan Africa
CID 2016, 62(S1); 42-46

Overview of this and other TSAP studies in the journal supplement: Lessons learned from TSAP
Clinical Infectious Diseases 2016:62 (Suppl. 1)

German Center for Infection Research

Related Antibiotics Articles:

Antibiotics promote resistance on experimental croplands
Canadian researchers have generated both novel and existing antibiotic resistance mechanisms on experimental farmland, by exposing the soil to specific antibiotics.
Why antibiotics fail
UCSB biologists correct a flaw in the way bacterial susceptibility to these drugs is tested.
Fungi have enormous potential for new antibiotics
Fungi are a potential goldmine for the production of pharmaceuticals.
Antibiotics can boost bacterial reproduction
The growth of bacteria can be stimulated by antibiotics, scientists at the University of Exeter have discovered.
Last-line antibiotics are failing
The ECDC's latest data on antimicrobial resistance and consumption shows that in 2015, antibiotic resistance continued to increase for most bacteria and antibiotics under surveillance.
Two antibiotics fight bacteria differently than thought
Two widely prescribed antibiotics -- chloramphenicol and linezolid -- may fight bacteria in a different way from what scientists and doctors thought for years, University of Illinois at Chicago researchers have found.
Preserving the power of antibiotics
News release describes efforts to address inappropriate antibiotic prescribing in emergency departments and urgent-care centers nationwide, which a JAMA study published this past May found rates as high as 50 percent for acute respiratory infections in US emergency departments.
Antibiotics could be cut by up to one-third, say dairy farmers
Nine in 10 dairy farmers participating in a new survey from the Royal Association of British Dairy Farmers (RADBF) say that the farming industry must take a proactive lead in the battle against antibiotic resistance.
Antibiotics may be inappropriate for uncomplicated diverticulitis
Antibiotics are advised in most guidelines on diverticulitis, which arises when one or more small pouches in the digestive tract become inflamed or infected.
New book on Antibiotics and Antibiotic Resistance from CSHLPress
'Antibiotics and Antibiotic Resistance' from CSHLPress examines the major classes of antibiotics, together with their modes of action and mechanisms of resistance.

Related Antibiotics Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Bias And Perception
How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.
Now Playing: Science for the People

#513 Dinosaur Tails
This week: dinosaurs! We're discussing dinosaur tails, bipedalism, paleontology public outreach, dinosaur MOOCs, and other neat dinosaur related things with Dr. Scott Persons from the University of Alberta, who is also the author of the book "Dinosaurs of the Alberta Badlands".