PROJECT TOPIC ON CHARACTERIZATION OF ANTIBIOTIC RESISTANCE GENES FROM SALMONELLA ASSOCIATED WITH INVASIVE SALMONELLOSIS IN SELECTED HOSPITALS IN KATSINA STATE, NIGERIA
The present research work was carried out to characterize the antibiotic resistance of Salmonella serovars associated with invasive salmonellosis in selected hospitals in Katsina State. A total of 300 blood samples was collected from the patients at three General hospitals [General hospital Katsina, Daura and Baure] and were processed according to standard microbiological technique for isolation and identification ofSalmonella typhiand Salmonella paratyphiA from 14 samples,the result of serotyping (slide agglutination) of the isolates indicates that nine (9) serovars belonged to D group while five (5) of the serovars belonged to A group.
The antibiotic susceptibility test that was carried out among the isolates against seven (7) antibiotics showed 88.9% resistance to ampicillin by Salmonella entericaserovarTyphi only, 100% resistance to penicillin G by both serovars and 100% sensitivity to ampicillin (by Salmonella paratyphi A only), Chloramphenicol, Gentamicin, Cephalex, Ofloxacin and Trimethoprim – sulfomethoxazole.
The PCR analysis detected the presenceof blaTEM-1gene in eight (8) serovars of Salmonella entericaserovarTyphi only.This study confirmed the presence of Salmonella entericaserovarTyphi and Salmonella entericaserovarParatyphi A as the cause of invasive salmonellosis in the study, their susceptibility and resistance to antimicrobial agents. The study emphasized the use of antibiotics likeofloxacin, cephalex chloramphenicol and septrin for treating enteric fever.
Salmonellae are Gram negative, non-sporing, motile, and non-lactose fermenting rods. They belong to the phylum Proteobacteria, class Gamma-proteobacteria, order Enterobacteriales, family Enterobacteriaceae and genus; Salmonella. With the exception of Salmonella Pullorun and Salmonella gallinarumall Salmonellae are motile, also with the exception of Salmonella typhi all are non-capsulated. The genus was named in honor of Daniel Elmer Salmon an American Veterinary Pathologist (Graham 2009 ; FDA/CFSAN, 2009).
Salmonellae can be divided into two major groups for the purpose of understanding of the genus. Group one includes the members of the genus that involved the most invasive salmonellae which cause enteric fever/typhoid fever (Typhoidal Salmonellosis) and group two are the Non-typhoidal salmonellosis (NTS) (Graham 2009).
An infection (salmonellosis) is caused by ingesting salmonellae in food that has been contaminated with animal or human intestinal sources directly or indirectly (Redmond and Griffith,2003). Common sources of the infection are contaminated foods such as poultry meat and meat products, eggs and eggs products or water (Udezeet al.,2010). Once the bacteria are in the body, the incubation period is only about 8 to 48 hours(Willey et al., 2008).
The disease results from a true food borne infection because the bacteria multiply and invade the intestinal mucosa where they produce an enterotoxin that destroys the epithelial cells. Abdominal pain, cramps, diarrhea, nausea, vomiting, and fever are the most prominent symptoms, which usually persist for 2 – 5 days but can last for several weeks (Willey et al.,2008). During the acute phase of the infection as many as one billion salmonellae can be found per gram of faeces.
Most adult patients recover, but the loss of fluids can cause problems for children and elders, blood and mucous may be present in faecal specimen (Al-jurayyanet al., 2004). Salmonellae can be isolated from stool, food, blood, urine, bone narrow and duodenal aspirates. From blood the organisms can be detected in about 75-90% of patients during the first ten days of infection, and in about 30% of patients during the third week. From faeces, organisms can usually be isolated from about 40% to 50% of patients during the second week of infection and about 80% of patients during the third week (Cheesborough, 2002).
Salmonella pathogenicity depends on a variety of virulence factors that help the pathogens in adhesion and invasion mechanisms (Gebreyeset al.,2009). The Salmonella incorporates plasmid (spv) on which are borne virulence genes potentiate the systemic spread of the pathogen and in its replication in extracellular sites (Gebreyeset al., 2009: Huret al., 2011). Other important virulence factors include the rck genes product which encodes an outer membrane protein and induces resistance to complement mediated killing (Fluit, 2005) and mediate adherence and invasion to cultured eukaryotic cell line(Hoet al., 2010).
The sop proteins (Sop A – E) (Sop) and the heat labile Salmonellaenteretoxin (stn) serve as effector proteins which are involved in the pathogenesis of Salmonella (Wallis and Galyov, 2000: Van Asten and Van Dijk, 2005).
The mgtc genes encodes mgtB2+ mg transporter and helps the pathogen to survive within the macrophages (Alix and Blanc Potard, 2007). Invasion genes (invA) exist in the majority of the Salmonella serovars and is related to intestinal mucosa invasion (Fluit 2005, Chuanchuenet al., 2010).
Treatment is with fluids and electrolytes replacement, use of effective antimicrobial therapies which reduce morbidity and mortality from typhoid fever (WHO, 2004). Without treatment, the disease may last for 3-4 weeks and case fatality rates may exceed 15% but with appropriate treatment, clinical symptoms fall drastically within few days and mortality rate reduced to 1% (WHO, 2004).
Prevention depends on good food processing practices, proper refrigeration and adequate cooking of food (Griffith, 2003). However, the incidence of cases and death has been greatly increased by a combination of poor sanitation and hygiene, unavailability of vaccines and higher cost of effective antimicrobial chemotherapy. Besides, the effectiveness of antimicrobial therapy is also being challenged by the emergence of antibiotic resistance antibiotic resistance (Woodsford and Ellington 2007). In Nigeria the antibiotics most frequently available for the treatment of typhoid are chloramphenicol, ampicillin, and cotrimoxazole.
With the emergence of plasmid-encoded chloramphenicol resistance (Mandalet al., 2004,) ampicillin, although slightly less effective than chloramphenicol was used both for therapy and elimination of the carrier state (Cooke and Wain, 2004).Antimicrobial resistance is a growing public health problem which causes increased morbidity and mortality among humans and animals.
Antimicrobials are used for treatment of infected human or animals, to protect them from infectious diseases or to provide a faster growth rate (Turkyilmaz et al., 2009). The routine use of antibiotics in medical and agricultural circles has resulted in the development of genetic mechanisms for the dissemination of antibiotic gene cassette, especially within and between species of gram negative (Tulkyilmazet al., 2009).
Salmonella serovars have often accumulated antibiotic resistance gene by plasmid transfer or by transposons or integron – mediated mechanisms and have routinely harboured these resistance genes on plasmids (Tulkyilmazet al., 2009). Notably, class I integrons have been found in many multi resistance organisms and many gram negative species. Class I integrons contain a 5‘– conserved segments (5‘ CS) that includes the integraseintII gene, the attII recombination site and pc promoter. It is followed by a variable region where one or more gene cassettes are located. This class of integron also contains a 3‘ conserved segment (3‘ CS) that include the sul1 which encode resistance to sulphonamides (Maria et al., 2011).
1.1 Statements of the Research Problem
Typhoid fever otherwise known as enteric fever is a common world-wide illness, transmitted by the ingestion of food contaminated with faeces from an infected person. It remains a serious public health problem in many regions of the world especially in developing countries, where it became endemic. Approximately 21.5million cases occur per annum worldwide with 200,000 deaths in Asia, Africa and Latin America. About 80% of deaths due to Salmonella are found in Africa (Oyangoet al.,2009).
CHARACTERIZATION OF ANTIBIOTIC RESISTANCE GENES FROM SALMONELLA ASSOCIATED WITH INVASIVE SALMONELLOSIS IN SELECTED HOSPITALS IN KATSINA STATE, NIGERIA
In Nigeria Typhoid and Paratyphoid are endemic and present similar clinical signs and symptoms with other diseases like malaria, hepatitis, and jaundice, as a result the disease is wrongly treated (Oloweet al.,2007).Indiscriminate antibiotic prescription for the treatment of typhoid fever, illegal selling of substandard drugs in the markets, resistance plasmid transfers from one strain of Salmonella to another or from close species are the major problems in the treatment of salmonellae (Huret al.,2011).
Salmonellosis still remains a serious public health problem in many developing countries with significant morbidity and mortality, therefore, the understanding of the distribution and causative serovars is necessary in reducing the disease (Boyd et al., 2004).
Antimicrobial resistance is increasing in many parts of the world (Olowe, et al., 2007). The knowledge of susceptibility pattern will provide the desired information for choosing the primary drugs that will minimize the development of resistance (Fluit, 2005).
Multi-antibiotics resistance Salmonella entericais rarely reported from Africa (especially South and Central) (Mirzaet al., 2000). In relation to effective surveillance and the development of rational control strategies for this important human disease, the availability of detailed and accurate data related to molecular epidemiology of Salmonella species is important (Mirzaet al., 2000).
The characterization of antibiotics resistance genes in Salmonella would be very important for medical workers, public health and pharmaceutical industries in developing countries such as Nigeria where there are extremely limited data (Adeshinaet al., 2010).
Typhoid and paratyphoid remain an important but under estimated disease which has high mortality in developing countries. However, there are extremely limited data in Northern Nigeria (especially Zaria, Kano and Katsina) (Adeshinaet al., 2010). Hence the probable under estimation of the disease burden in the area.
1.3 Aim of the Study
The aim of this research was to characterized the antibiotics resistance of Salmonella species associated with invasive Salmonellosis in selected hospitals in Katsina State.
1.4 Objectives of the Study
- To isolate and characterize the Salmonella serovars associated with invasive salmonellosisfrom patients attending selected hospitals in Katsina State
- To determine the prevalence of Salmonella serovars associated with invasive salmonellosis in Katsina State.
- To determine the antibiotics susceptibility of the Salmonella isolates to selected antibiotics.
- To identify theblaTEM genes in Salmonella serovars using PCR methods.
See Also : ENTERIC PATHOGENIC BACTERIA AND ASSOCIATED RISK FACTORS IN DIARRHOEIC AND DYSENTERIC CHILDREN IN SOKOTO STATE, NIGERIA