Phenotypic Characterization Species Salmonella Associated Non-Typid of with Severe Malaria in Children Admitted to Kilifi District Hospital.
Abstract
Infections caused by both typhoid salmonella and non-typhoid Salmonellae
,
(NTS) species cause major health problems such as acute gastroenteritis, typhoid
fever, severe bacteraemia
and septicaemia that result in high morbidity and
mortality. Non-typhoid Salmonellae species are amongst the most common causes
of invasive bacterial childhood disease in sub-Saharan Africa. Malaria is a major
cause of global morbidity and mortality and may be responsible for between one to two million childhood deaths each year in sub-Saharan Africa alone. A study to
determine the association between sever malaria and non-typhi salmonella in
children was carried out during a 54-month period between January 1997 and June
2001 at the Kili:fiDistrict Hospital on the coast of Kenya. The ages of the children
varied between 3 months and 123 months (median 21 months, Inter Quartile Range
10 - 35 months). During this period 9147 children with severe malaria were
admitted at this hospital. A total of 19,118 blood cultures obtained from all
admissions and 1820 stool cultures were performed which yielded positive growth
of 7.3 % and 19% respectively. Non-typhi salmonella were isolated from 18.6% of
the positive blood cultures and 28.4% of the stool cultures out of which a total of
101 NTS occurred in children with severe malaria. Out of the 9147 malaria cases
admitted during this period of time 1.10% had concomitant NTS infection.
Non
typhi Salmonella with severe malaria as a ratio of all malaria admissions for the
period varied between 0.8% and 1.5%. The NTS isolates occurring with severe
malaria showed varying levels of antibiotic resistance. They were resistant to
ampicillin (35%), chloramphenicol (18%), gentamicin (22%), Cefuroxime (29%),
co-trimoxazole
(39%),
ciprofloxacin
(3%),
cefotaxime
(14%),
amoxycillin-
clavulanic acid (26%) and tobramycin (18%). Multidrug resistance (MDR) was
seen in 34% of the isolates. Some of this resistance was transferable. There was a
significant association between clinical outcome and male sex of the patient. It can
be concluded from this study that NTS and severe malaria occurring together are a
major problem in this area and that a large number of the isolates are MDR. A high
mortality has also been associated with these diseases in this area with a significant
association with the male patients. Two major salmonella serotypes are responsible
for this infection namely S. typhimurium and S. enteritidis. It is proposed that
during the sequestration of Plasmodium parasites, they make these vessels porous
and hence open them up to invasion by salmonella from the gut. The salmonellae
find a medium rich in iron, which it needs both for growth and virulence. This may
explain why an occurrence of both NTS and Plasmodium leads to a severe illness,
which has high mortality. A more controlled study is required to elucidate the chain
of events of both NTS and malaria parasite co-existence.