Analysis of Trends in Resistance to Fluoroquinolones and Extended Spectrum Beta-Lactams among <i>Salmonella</i> Typhi Isolates Obtained from Patients at Four Outpatient Clinics in Nairobi County, Kenya

Abstract

Typhoid fever caused by the bacterium Salmonella enterica serovar Typhi (S.Typhi) causes an estimated 25 million illnesses and approximately 200,000 deaths annually mostly in developing countries. Although the management of typhoid fever has been effectively through antibiotic treatment, S. Typhi is increasingly becoming resistant to the currently recommended drugs. This study utilized a quasi-experimental design focusing on archived samples to describe antimicrobial susceptibility patterns of S. Typhi and determine the genetic basis of resistance to the two most commonly used classes of antimicrobials. A total sample size of 287 isolates of S. Typhi isolates stored in −80˚C freezer at the Centre for Microbiology Research was utilized. Isolates were subjected to antimicrobial susceptibility testing to commonly available antimicrobials using disk diffusion method, then analyzed for trends in resistance to fluoroquinolones and extended spectrum beta lactams. Among the 287 isolates 158 (55.5%) were found to be Multi Drug Resistant (MDR). This implied that these isolates were resistant to all first line classes of treatment such as ampicillin, chloramphenicol and sulfamethoxazole-trimethroprim. In addition to this, these isolates were also resistant to at least one of the currently recommended drugs of choice, either a β-lactam or a fluoroquinolone. This study observed resistances at 18.2% and 15.4% to fluoroquinolones and cephalosporins respectively. PCR results revealed presence of bla TEM , bla INT and bla CTX-M genes coding for resistance to β-lactams in 80% of the isolates that had combined resistance to β-lactams and fluoroquinolones. It is likely that

Salmonella Typhi genotypic diversity, cluster identification and antimicrobial resistance determinants in Mukuru settlement, Nairobi Kenya

“…Mukuru Settlement is one of Nairobi’s largest and most crowded urban slums and is home to over 250,000 people [ 6 ]. As an informal settlement, there is a shortage of safe drinking water and inadequate infrastructure and sanitation, which predisposes people to typhoid fever [ 1 ]. Moreover, patients have easy access to over-the-counter medications, which fuels the growth and spread of antibiotic resistance [ 15 ].…”

“…Moreover, patients have easy access to over-the-counter medications, which fuels the growth and spread of antibiotic resistance [ 15 ]. For instance, Kavai et al (2018) reported an MDR prevalence of 55.5% in S. Typhi isolates from outpatient clinical samples from Mukuru villages in Nairobi [ 1 ]. To effectively develop typhoid control and prevention methods, it is important to understand the epidemiological dynamics of Salmonella Typhi in this setting.…”

“…Studies such as Ng’eno et al (2023) have explored the disease burden in Kibera, an urban settlement, over 10 years (2010–2019) and reported a resurgence of typhoid fever in 2019 after a prolonged period of low rates, with the highest incidence among children and a high multidrug-resistant (MDR) prevalence of 71.9% [ 5 ]. Other studies from Kenya have also reported on the high prevalence of MDR S .Typhi strains [ 1 , 6 ]. These findings highlight the need for ongoing surveillance and targeted interventions.…”

“…Salmonella enterica subspecies enterica serovar Typhi is the causative agent of typhoid fever, a disease endemic to overpopulated urban areas, characterized by overcrowding, poor sewage systems, and poor hygiene and sanitation standards [ 1 ]. Typhoid fever causes approximately 26.9 million cases and 217,000 deaths yearly, mainly affecting children and the elderly [ 2 ].…”

Evaluation ofstaA,viaBandsopEgenes inSalmonelladetection using conventional polymerase chain reaction (PCR)

“…Salmonella strains were obtained from the Centre for Microbiology Research (CMR) at the Kenya Medical Research Institute (KEMRI) [17,18] and Kenyatta national hospital [14] in Nairobi, Kenya. The isolates were confirmed using slide agglutination techniques, conventional…”