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Investigating the decay rates of Escherichia coli relative to Vibrio parahemolyticus and Salmonella Typhi in tropical coastal waters

Lee CW, Ng AY, Bong CW, Narayanan K, Sim EU, Ng CC

Water Res, 2011 Feb;45(4):1561-70.

PMID: 21146847 DOI: 10.1016/j.watres.2010.11.025

Using the size fractionation method, we measured the decay rates of Escherichia coli, Salmonella Typhi and Vibrio parahaemolyticus in the coastal waters of Peninsular Malaysia. The size fractions were total or unfiltered, <250 μm, <20 μm, <2 μm, <0.7 μm, <0.2 μm and <0.02 μm. We also carried out abiotic (inorganic nutrients) and biotic (bacterial abundance, production and protistan bacterivory) measurements at Port Dickson, Klang and Kuantan. Klang had highest nutrient concentrations whereas both bacterial production and protistan bacterivory rates were highest at Kuantan. We observed signs of protist-bacteria coupling via the following correlations: Protistan bacterivory-Bacterial Production: r = 0.773, df = 11, p < 0.01; Protist-Bacteria: r = 0.586, df = 12, p < 0.05. However none of the bacterial decay rates were correlated with the biotic variables measured. E. coli and Salmonella decay rates were generally higher in the larger fraction (>0.7 μm) than in the smaller fraction (<0.7 μm) suggesting the more important role played by protists. E. coli and Salmonella also decreased in the <0.02 μm fraction and suggested that these non-halophilic bacteria did not survive well in seawater. In contrast, Vibrio grew well in seawater. There was usually an increase in Vibrio after one day incubation. Our results confirmed that decay or loss rates of E. coli did not match that of Vibrio, and also did not correlate with Salmonella decay rates. However E. coli showed persistence where its decay rates were generally lower than Salmonella.

Matched MeSH terms: Salmonella typhi/growth & development; Salmonella typhi/isolation & purification*

Fulltext Salmonella Typhi genomics: envisaging the future of typhoid eradication

Yap KP, Thong KL

Trop Med Int Health, 2017 08;22(8):918-925.

PMID: 28544285 DOI: 10.1111/tmi.12899

Next-generation whole-genome sequencing has revolutionised the study of infectious diseases in recent years. The availability of genome sequences and its understanding have transformed the field of molecular microbiology, epidemiology, infection treatments and vaccine developments. We review the key findings of the publicly accessible genomes of Salmonella enterica serovar Typhi since the first complete genome to the most recent release of thousands of Salmonella Typhi genomes, which remarkably shape the genomic research of S. Typhi and other pathogens. Important new insights acquired from the genome sequencing of S. Typhi, pertaining to genomic variations, evolution, population structure, antibiotic resistance, virulence, pathogenesis, disease surveillance/investigation and disease control are discussed. As the numbers of sequenced genomes are increasing at an unprecedented rate, fine variations in the gene pool of S. Typhi are captured in high resolution, allowing deeper understanding of the pathogen's evolutionary trends and its pathogenesis, paving the way to bringing us closer to eradication of typhoid through effective vaccine/treatment development.

Matched MeSH terms: Salmonella typhi/genetics*; Salmonella typhi/pathogenicity

Fulltext Analysis of Salmonella enterica Serovar Typhi by Outer Membrane Protein (OMP) Profiling, Random Amplification of Polymorphic DNA (RAPD) and Pulsed Field Gel Electrophoresis (PFGE)

Kumar Y, Mani KR, Tahlan AK

Trop Life Sci Res, 2019 Jan;30(1):57-71.

PMID: 30847033 DOI: 10.21315/tlsr2019.30.1.4

A number of countries, including developed countries, still have typhoid fever as a major problem resulting in frequent outbreaks. The importance of controlling spread of typhoid fever is well known and necessitates periodic studies to delineate epidemiological relationships. Although phage typing remains to be the preferred conventional method for characterisation of typhoid bacilli, it is of limited use due to prevalence of few predominant phage types in the country like India. Therefore, an effort has been made to assess three molecular methods [Outer Membrane Protein (OMP) Profiling, Random Amplification of Polymorphic DNA (RAPD) and Pulsed Field Gel Electrophoresis (PFGE)] for typing of Salmonella enterica serovar Typhi. 128 Salmonella enterica serovar Typhi isolates were identified using biotyping and serotyping followed by antimicrobial susceptibility testing. These isolates were further subjected to OMP analysis, RAPD and PFGE. PFGE (114 unique clusters) was found to be the most discriminatory method followed by RAPD (94 unique clusters) and OMP profiling (50 unique clusters). Multidrug resistant strains were well discriminated by all three methods used in the study. PFGE still remains the most preferred method for detailed epidemiological investigations. However, random amplification of polymorphic DNA and outer membrane protein profiling can also be considered for molecular discrimination of the isolates in the laboratories lacking high-end facilities.

Matched MeSH terms: Salmonella typhi

Typhoid fever presenting as acute psychosis in a young adult: case report and literature review of typhoid psychosis

Esa H, Norazlah B, Hameed AA, Ding CH, Wahab AA

Trop Biomed, 2021 Jun 01;38(2):192-195.

PMID: 34172710 DOI: 10.47665/tb.38.2.057

The rarity of acute psychosis in typhoid fever can result in delayed and misdiagnosis of the condition. We report a case of a 20-year-old man who presented with fever and acute psychotic symptoms. This was associated with headache, dizziness, and body weakness. There were no other significant symptoms. Neurological examination revealed reduced muscle tone of bilateral lower limbs but otherwise unremarkable. The computed tomography (CT) scan of his brain showed no abnormality. Blood specimens for microbiological culture grew Salmonella Typhi. This isolate was susceptible to chloramphenicol, ampicillin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole. He was treated with intravenous ceftriaxone for one week and responded well. He was discharged with oral ciprofloxacin for another week. The repeated blood and stool for bacterial culture yielded no growth of Salmonella Typhi.

Matched MeSH terms: Salmonella typhi

Genetic dynamics of Salmonella typhi--diversity in clonality

Pang T

Trends Microbiol., 1998 Sep;6(9):339-42.

PMID: 9778724

Matched MeSH terms: Salmonella typhi/genetics*; Salmonella typhi/pathogenicity

Typhoid fever--important issues still remain

Pang T, Levine MM, Ivanoff B, Wain J, Finlay BB

Trends Microbiol., 1998 Apr;6(4):131-3.

PMID: 9587187

Matched MeSH terms: Salmonella typhi/drug effects; Salmonella typhi/genetics

Travellers take heed: Outbreak of extensively drug resistant (XDR) typhoid fever in Pakistan and a warning from the US CDC

Saleem Z, Hassali MA

Travel Med Infect Dis, 2018 10 16;27:127.

PMID: 30339826 DOI: 10.1016/j.tmaid.2018.10.013

Matched MeSH terms: Salmonella typhi/drug effects

Generation of a naïve human single chain variable fragment (scFv) library for the identification of monoclonal scFv against Salmonella Typhi Hemolysin E antigen

Lim BN, Chin CF, Choong YS, Ismail A, Lim TS

Toxicon, 2016 Jul;117:94-101.

PMID: 27090555 DOI: 10.1016/j.toxicon.2016.04.032

Antibody phage display is a useful tool for the isolation and identification of monoclonal antibodies. Naive antibody libraries are able to overcome the limitations associated with the traditional hybridoma method for monoclonal antibody generation. Antibody phage display is also a preferred method for antibody generation against toxins as it does not suffer from toxicity mediated complications. Here, we describe a naïve multi ethnic scFv antibody library generated via two-step cloning with an estimated diversity of 2 × 10(9). The antibody library was used to screen for monoclonal antibodies against Hemolysin E antigen, a pore forming toxin produced by Salmonella enterica serovar Typhi. A soluble monoclonal scFv antibody against the HlyE toxin (IgM scFv D7 anti-hlyE) was isolated from the library. This shows the value of the naïve library to generate antibodies against toxin targets in addition to the potential use of the library to isolate antibodies against other immunogenic targets.

Matched MeSH terms: Salmonella typhi/genetics; Salmonella typhi/immunology*

Fulltext Retrospective review of dot enzyme immunoassay test for typhoid fever in an endemic area

Jackson AA, Ismail A, Ibrahim TA, Kader ZS, Nawi NM

Southeast Asian J. Trop. Med. Public Health, 1995 Dec;26(4):625-30.

PMID: 9139364

Typhoid fever remains a common problem in Malaysia, but for its diagnosis both blood culture and the Widal test have drawbacks. A dot enzyme immunoassay (EIA) has been developed which detects IgM and IgG antibodies to a specific 50 kDa outer membrane protein on Salmonella typhi. This study was performed among outpatients attending the university hospital in Kelantan, a state on the east coast of Peninsular Malaysia where typhoid is endemic. The dot EIA was done on 149 outpatients of all ages in whom typhoid was suspected. Of these, 60 were not analysable due to insufficient data. The other 89 were retrospectively classed as typhoid (total = 21), or not typhoid (total = 68). The criteria for diagnosis of typhoid was either, blood culture was positive, or with blood culture negative, temperature was at least 38 degrees C and Widal O and/or H titer greater than or equal to 1/160. We then compared the diagnosis with the EIA result. For the result where either IgM or IgG was positive, sensitivity was 90%, specificity 91% and negative predictive value 97%. For IgM positive, specificity was 100%. But the specificity of IgG positive alone was reduced by six false positives, which were probably due to persistence of IgG after acute infection. Other cases were found where IgG positive alone appeared in the first week of typhoid fever, probably due to rapid response in a second or subsequent infection. We also found that IgM-producing patients were significantly younger than those showing IgG alone positive.
Study site: Community Medicine clinic, Accident & emergency department, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia

Matched MeSH terms: Salmonella typhi/immunology*

Fulltext Dot enzyme immunosorbent assay for the serodiagnosis of typhoid fever

Ismail A, Kader ZS, Kok-Hai O

Southeast Asian J. Trop. Med. Public Health, 1991 Dec;22(4):563-6.

PMID: 1820645

A nitrocellulose membrane strip dotted with a specific 50 kDa outer membrane protein of Salmonella typhi was applied for the serodiagnosis of typhoid fever. Using horseradish peroxidase conjugated IgM and IgG antibodies with 4-chloronaphthol as substrate, antibodies in typhoid patients were clearly visualised as bluish purple dots while sera from patients with non-typhoid fevers gave negative results. The detection of specific IgM and IgG antibodies in typhoid patients suggest either recent or current infection. Combined with the high specificity, reliability and rapidity of the test, the dot EIA technique provides a simple and useful method for the serodiagnosis of typhoid using a single serum specimen.

Matched MeSH terms: Salmonella typhi/isolation & purification*

False-positive widal test in nontyphoid Salmonella infections

Pang T, Pothocheary SD

Southeast Asian J. Trop. Med. Public Health, 1989 Mar;20(1):163-4.

PMID: 2672364

Matched MeSH terms: Salmonella typhi/isolation & purification; Salmonella typhimurium/isolation & purification

Infections in post-tsunami victims

Othman N, Ismail IH, Yip R, Zainuddin Z, Kasim SM, Isa R, et al.

Pediatr Infect Dis J, 2007 Oct;26(10):960-1.

PMID: 17901807 DOI: 10.1097/INF.0b013e3181257234

Two tsunami survivors from Banda Acheh, Sumatra, presented with pyrexia of unknown origin and a nonresolving left-sided empyema, respectively. Both children had mixed infections of tuberculosis and melioidosis; Salmonella typhi was also present in the second patient. Mixed infections are common late sequela complications in post-tsunami victims.

Matched MeSH terms: Salmonella typhi/isolation & purification

Fulltext Ciprofloxacin-resistant Salmonella enterica serotype typhi in a patient with osteomyelitis of the rib

Wilson G, Prabhu N, Easow JM, Mukhopadhyay C

Med J Malaysia, 2005 Dec;60(5):667-9.

PMID: 16515126

Salmonella osteomyelitis of the rib is a rare clinical entity. In our case, a muhidrug resistant Salmonella enterica serotype Typhi was isolated from an immuno-competent patient with osteomyclitis of the ribs, who was treated earlier with ciprotloxacin for typhoid fever. The patient was successfully treated for osteomyclitis with intravenous ceftriaxone.

Matched MeSH terms: Salmonella typhi*

Fulltext Imported cases of chloramphenicol resistant Salmonella typhi

Cheong YM, Jegathesan M

Med J Malaysia, 1992 Dec;47(4):331.

PMID: 1303490

Matched MeSH terms: Salmonella typhi/drug effects*

Fulltext Standardisation of the Widal test

Cheong YM, Jegathesan M

Med J Malaysia, 1989 Sep;44(3):267.

PMID: 2483249

Matched MeSH terms: Salmonella typhi/immunology

Fulltext First isolates of chloramphenicol resistant S. typhi in Malaysia

Jegathesan M, Khor SY

Med J Malaysia, 1980 Jun;34(4):395-8.

PMID: 7219270

Four strains of S. typhi isolated in Malaysia were found to show resistance to chloramphenicol and other antibiotics. In two of these strains it was possible to show that this resistance was transferable.
This problem which is widespread in neighbouring countries and undetected in Malaysia till recently has now been shown to exist in this country. Fears that the incidence of such strains will increase in the future are expressed and the need for vigilance is emphasised.

Matched MeSH terms: Salmonella typhi/drug effects; Salmonella typhi/isolation & purification*

Fulltext Plasmid-mediated transferable chloramphenicol and tetracycline resistance in Salmonella typhi (Vi phage type 25) isolated in Peninsular Malaysia

Koh CL, Lim ME, Wong YH

Med J Malaysia, 1983 Dec;38(4):320-4.

PMID: 6599991

A clinical isolate of Salmonella typhi (Vi phage type 25), resistant to chloramphenicol, streptomycin and tetracycline, was examined for the presence of R plasmids. Results from conjugation, agarose gel electrophoresis and transformation experiments indicated that it harboured a single large self-transmissible R plasmid which coded for both the chloramphenicol and tetracycline resistance traits.

Matched MeSH terms: Salmonella typhi/drug effects; Salmonella typhi/genetics*; Salmonella typhi/isolation & purification

Prevalence and antimicrobial resistance profile of Salmonella typhi infection in Iraq, 2019-2021

Nassir KF, Ali BM, Ibrahim ZH, Qasim ZJ, Mahdi SG, Mustafa NM, et al.

Med J Malaysia, 2024 Jan;79(1):74-79.

PMID: 38287761

INTRODUCTION: Salmonella typhi could infect the intestinal tract and the bloodstream or invade body organs and secrete endotoxins. It is endemic in developing countries. It is increasingly evolving antimicrobial resistance to several commonly used antimicrobial agents.

MATERIALS AND METHODS: A cross-sectional study was done at Iraqi Communicable Disease Control Center, where all confirmed cases of Salmonella typhi are reported, for a period 2019-2021. All demographic, epidemiological and clinical characteristics of patients, comorbidities, type of samples, distribution of S. typhi by age and gender, time distribution in each year and profile of bacterial resistance and sensitivity to antibiotics were gathered and analysed.

RESULTS: Most samples were taken from blood. The mean age of cases during 2019, 2020 and 2021 was 18.7 ± 6.5, 17.7 ± 14.1 and 17.3 ± 12.8. Males constituted 56.7%, 58.5% and 39.8%, respectively. Some cases had comorbidities. Most cases had headache and fever. Some of them had nausea, diarrhoea, vomiting and epigastric pain. The age and sex were significantly associated with years of reporting. The most months of case reporting were June-July (2019 and 2021), Jan. -Feb. (2020). There was an obvious increase in S. typhi resistance to ceftriaxone (92.2%, 86.1%, 88.8%) and ampicillin (77.1%, 76.9%, 81.27%). There was a gradual increase in sensitivity to tetracycline (83.1%, 88.1%, 94%), cotrimoxazole (86.7%, 86.1%, 92.2%), ciprofloxacin (78.3%, 90.1%, 87.8%) and cefixime (77.7%, 72.3%, 72.7%).

CONCLUSIONS: There was a sharp rise in resistance rates of the S. typhi in Iraq (during 2019-2021) to ceftriaxone and ampicillin, while there were highest sensitivity rates to imipenem, aztreonam and chloramphenicol. The following recommendations were made: (1) Improvement of general hygiene and food safety measures. (2) Emphasis on vaccination and surveillance of Salmonella infection. (3) Rational use of appropriate antibiotics through implementation of treatment guidelines. (5) Educate communities and travelers about the risks of S. typhi and its preventive measures.

Matched MeSH terms: Salmonella typhi

Multiple drug resistance and the presence of R factors in enteric pathogens

Sng EH, Lam S

Med J Malaya, 1971 Jun;25(4):301-4.

PMID: 4261307

Matched MeSH terms: Salmonella typhi/drug effects

A survey of Salmonella VI-phage types occurring in Federation of Malaya and Singapore

Singh RB

Med J Malaya, 1966 Mar;20(3):215-20.

PMID: 4223129

Matched MeSH terms: Salmonella typhi/isolation & purification*

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