Salmonella typhi infection in a tertiary institution in Nasarawa State, Nigeria

ObjectiveTo evaluate the prevalence of Sabmonella typhi (S.typhi) among subjects attending College of Education Health Clinic, Akwanga, Nasarawa state from the year. 2005 to 2007 and to recommend some preventive measures to the populace.MethodsBlood samples were tested for infection using the widal test.ResultsOut of the 793 patients examined, 579(73.0%) were positive with 174 (30.05%), 254(43.86%) and 151(26.07%) for the years 2005, 2006 and 2007 respectively. The age range with the highest prevalence of infection for the period was 21–30 with 207(35.75%) followed by 31–40 year group with 133 (22.97%). Chi-square analysis showed no significant difference in infection between males and females (P>0.05).ConclusionsThe results of this study provide a useful guide in the formulation of S. typhi control measures in tertiary institutions in the State and also help to check the spread of the pathogen in the general population.     

An unusual late manifestation of a Salmonella typhi infection

We report the case history of a patient in whom we diagnosed purulent lymphadenitis due to Salmonella typhi, a late complication of a febris typhoidea that occurred 11 yr previously. We also review the literature concerning complications of Salmonella infections, and particularly discuss their hematogenous spread and lodgment.     

Salmonella krefeld in Thailand: I. Epidemiology, infection and drug resistance

Information from the National Salmonella Shigella Center (NSSC), Thailand indicated that the most frequently isolated Salmonella serotype from humans during 1974-1975 was Salmonella typhi (33.1%), during 1976-1982 was S. krefeld (26.6%) and during 1983-1987 was S. derby (12.6%). Antimicrobial susceptibility study of various Salmonella serotypes indicated that S. krefeld was the serotype with multiple drug resistance persisting for the longest period of time. Human salmonellosis due to S. krefeld is very rare. During 1976-1978, a large outbreak of S. krefeld gastroenteritis occurred in Thailand, mainly in children. The outbreak spread countrywide and is currently endemic. Gastrointestinal symptoms are severe in young infants. Systemic invasion with bacteremia, meningitis and pneumonitis were reported. The antimicrobial susceptibility pattern of isolates varied from sensitive to multiply drug resistant. The common antibiotic resistances were to ampicillin (75-92%), chloramphenicol (33-75%), kanamycin (67-90%) and sulfamethoxazole-trimethoprim (15-52%). Resistance to gentamicin and sulfamethoxazole-trimethoprim declined after the period of the epidemic. Antimicrobial resistance patterns of 150 S. krefeld strains isolated in Thailand during 1978-1987 showed multiple drug resistance with up to seven drugs. The most common patterns were ApCmKmSuTp and ApCmKmSmSuTc.     

Association between the acquired immunodeficiency syndrome and infection with Salmonella typhi or Salmonella paratyphi in an endemic typhoid area

Eight cases of typhoid and paratyphoid fever were identified during a 4-year period in a cohort of 117 patients who were positive for human immunodeficiency virus in Lima, Peru. Asymptomatic patients with human immunodeficiency virus infection and patients with the lymphadenopathy syndrome had a typical clinical presentation and response to therapy. Patients with the acquired immunodeficiency syndrome who were culture positive for Salmonella typhi or Salmonella paratyphi presented with fulminant diarrhea and/or colitis; the two patients for whom at least 2 months of follow-up were available relapsed. In our cohort there were 0.06 cases of typhoid or paratyphoid per patient year of observation; this rate is approximately 60 times that in the general population in Lima, and 25 times that in the 15- to 35-year-old age group. Our data indicate that patients who are positive for human immunodeficiency virus are at significantly increased risk for infection with S typhi and S paratyphi, and suggest that the clinical presentation of these diseases in patients with the acquired immunodeficiency syndrome differs from that seen immunocompetent hosts.     

A Case of Salmonella typhi Endocarditis in Pregnancy

Infective endocarditis (IE) is an uncommon but life-threatening infection during pregnancy. Although there have been several reports of endocarditis caused by Salmonella typhi, to our knowledge it has not been reported as a cause of endocarditis during pregnancy. We report a case of 27-year-old pregnant woman with aortic valve IE caused by S. typhi, who had moderate mitral stenosis and aortic regurgitation. During pregnancy, fever, increase in sedimentation should always alert the physician about the possibility of IE, especially in the presence of predisposing clinical conditions. Whenever possible, transesophageal echocardiographic evaluation should be performed because transthoracic echocardiography might not always demonstrate vegetation as in the present case.     

Calcified splenic abscess, colonic fistula and ascites in a chronic carrier of Salmonella typhi

We report the unusual case of a patient with chronic carriage of Salmonella typhi who presented with partially calcified splenic abscess linked to colic fistula and ascitis. The colic fistula could be secondary to ischemic necrosis by left colon compression due to spleen large abscess. Fistula was evidenced by abdominal computed tomography scan and confirmed by barium enema. The possible etiologies of ascitis are either tuberculosis or ascitic peritonitis secondary to the fistulisation; nevertheless, the role of segmentary portal located hypertension cannot be completely excluded. The splenic abscess was probably due to Salmonella typhi which was only isolated from stool specimens. The calcified splenic abscess was the evidence that the infection had occurred first. In addition, the isolation of Salmonella typhi in stool cultures six months after the subject had returned from the Comores proved the chronic carriage. Treatment by splenectomy and left colectomy was successful in this patient.     

Plasmid-mediated multidrug resistance in Salmonella typhi in Kuwait

Multidrug resistant Salmonella typhi infection is common in Kuwait. Between January 1993 and December 1994, 266 strains of S. typhi were isolated from blood of suspected typhoid fever cases attending the Infectious Disease Hospital, Kuwait. Of these, 205 strains were isolated from patients from the Indian sub‐continent, 105 (45%) of which showed resistance to one or more drugs; 91 of these resistant strains showed resistance to the oral antimicrobials ampicillin, chloramphenicol, tetracycline and co‐trimoxazole (ACTCo). All 266 isolates were sensitive to fluoroquinolones and cephalosporines. The minimum inhibitory concentrations (MIC) for ampicillin, chloramphenicol and tetracycline in resistant strains were >1000 μg/ml. All 91 strains with ACTCo resistance pattern transferred their resistance to a recipient E. coli strain, whereas none of the remaining 14 strains with different resistance patterns transferred theirs. This paper reaffirms that multidrug resistant S. typhi is quite common in Kuwait and that such resistance is encoded by auto‐transferring plasmids.     

Plasmid-mediated resistance to multiple antibiotics in Salmonella typhi

Two hundred forty-one strains of Salmonella typhii isolated in Lima, Peru, from October 1981 through February 1983 were tested for susceptibility to antimicrobial agents. Seventy-two strains (29.9%) were resistant to chloramphenicol and other antibiotics, including ampicillin, sulfonamides, and trimethoprim. The minimal inhibitory concentrations of 17 antimicrobial agents were determined for all of these chloramphenicol-resistant strains. Sch 25393, new beta-lactams, new quinolones, and the formulation clavulanic acid-amoxicillin were effective against all the strains. Four different resistance patterns distributed among eight phage types were observed. The 72 resistant S. typhi could transfer the resistance marker into Escherichia coli C1, and all the plasmids belonged to the incompatibility group H1.     

Highly plastic chromosomal organization in Salmonella typhi.

Gene order in the chromosomes of Escherichia coli K-12 and Salmonella typhimurium LT2, and in many other species of Salmonella, is strongly conserved, even though the genera diverged about 160 million years ago. However, partial digestion of chromosomal DNA of Salmonella typhi, the causal organism of typhoid fever, with the endonuclease I-CeuI followed by separation of the DNA fragments by pulsed-field gel electrophoresis showed that the chromosomes of independent wild-type isolates of S. typhi are rearranged due to homologous recombination between the seven rrn genes that code for ribosomal RNA. The order of genes within the I-CeuI fragments is largely conserved, but the order of the fragments on the chromosome is rearranged. Twenty-one different orders of the I-CeuI fragments were detected among the 127 wild-type strains we examined. Duplications and deletions were not found, but transpositions and inversions were common. Transpositions of I-CeuI fragments into sites that do not change their distance from the origin of replication (oriC) are frequently detected among the wild-type strains, but transpositions that move the fragments much further from oriC were rare. This supports the gene dosage hypothesis that genes at different distances from oriC have different gene dosages and, hence, different gene expression, and that during evolution genes become adapted to their specific location; thus, cells with changes in gene location due to transpositions may be less fit. Therefore, gene dosage may be one of the forces that conserves gene order, although its effects seem less strong in S. typhi than in other enteric bacteria. However, both the gene dosage and the genomic balance hypotheses, the latter of which states that the origin (oriC) and terminus (TER) of replication must be separated by 180 degrees C, need further investigation.     

Heterogeneity of lipopolysaccharide phenotype among Salmonella typhi strains

Comparison of the Vi antigen, lipopolysaccharide, and protein components of the cell surface of three strains of Salmonella typhi showed that differences in lipopolysaccharide contributed most to distinctions in serum survival, whereas differences in Vi antigen content had no apparent effect.