blaCTX-M-I group extended spectrum beta lactamase-producing Salmonella typhi from hospitalized patients in Lagos, Nigeria

Abstract

PurposeThe global spread of blaCTX-M-I extended-spectrum beta-lactamase (ESBL)-producing Salmonella spp. remains a major threat to treatment and control. Evidence of emergence and spread of this marker are lacking in Nigeria. This study investigated blaCTX-M-I ESBL production among Salmonella isolates from hospitalized patients.MethodsPatients (158 total) made up of two groups were evaluated. Group A was composed of 135 patients with persistent pyrexia and group B was composed of 23 gastroenteritis patients and their stool samples. Samples were cultured, and isolates were identified and were subjected to antibiotic susceptibility testing by standard methods. Isolates were further screened for ESBL production, blaCTX-M-I genes and transferability by double disk synergy test, plasmid extraction, polymerase chain reaction, and conjugation experiment.ResultsThirty-five (25.9%) Salmonella isolates were identified from group A, of which 74.3% were S. typhi, 22.9% were S. paratyphi and two (5.7%) were invasive non-typhoidal S. enteritidis. Nine Plasmodium falciparum infections were recorded, four of which were identified as co-infections with typhoidal Salmonella. Only two (8.7%) S. enteritidis samples were obtained from group B (P>0.05). A total of 24 isolates were ESBL-positive, eliciting resistance to five to seven antibiotics, and were multiple-drug resistant. ESBL production due to the blaCTX-M-I gene cluster was detected in eleven (45.8%) Salmonella isolates. Nine (81.8%) of the eleven blaCTX-M-I ESBL producers were S. typhi and two (18.2%) isolates were S. enteritidis. Four of nine S. typhi blaCTX-M-I ESBL-producing strains harbored 23 kb self-transmissible plasmid that was co-transferred with cefotaxime and augmentin resistance to Escherichia coli j53-2 transconjugants.ConclusionThis study revealed the emergence of blaCTX-M-I S. typhi as an agent of persistent pyrexia with potential to spread to other Enterobacteriaceae in Lagos, Nigeria. Cautionary prescription and judicious use of third-generation cephalosporins, particularly cefotaxime, for the treatment of typhoid fever and routine screening for P. falciparum co-infection with ESBL-producing Salmonella in the laboratories during diagnosis of persistent pyrexia conditions in patients are recommended.

Occurrence of extended-spectrum and AmpC &beta;-lactamases in multiple drug resistant <em>Salmonella</em> isolates from clinical samples in Lagos, Nigeria

“…This is an indication of the increasing trend of ESBL in the clinical settings in our environment. In our previous report, ESBL production due to bla CTX-M-I gene cluster was detected in 45.8% of Salmonella isolates 18. This finding further affirmed the circulation of ESBL-producing Salmonella spp.…”

Extended-spectrum beta-lactamases producing extensively drug-resistant Salmonella Typhi in Punjab, Pakistan

“…An S. Typhi isolates encoding blaCTX-M15 gene on an IncY plasmid was recovered from the Democratic Republic of Congo [9]. Few other studies have reported the blaCTX-M producing S. Typhi isolates from Nigeria, Japan, and Southern India as well as from the travelers having a travel history to Iraq and Guatemala [5,[23][24][25][26]. More recently, S. Typhi strains harboring the blaCTX-M15 gene were isolated from Pakistan that was resistant to third-generation cephalosporin and fluoroquinolones as well as MDR phenotypes therefore and has been categorized as extensively drug-resistant (XDR).…”

Enteric fever in India: current scenario and future directions

“…In Nigeria, plasmid‐mediated CTX‐M1 has recently been reported in 9/25 blood culture isolates of S . typhi from Lagos .…”

“…Recent molecular work on two unrelated European travellers who acquired S. typhi in the Philippines suggests there may be an unrecognised outbreak of ESBL S. typhi there [74]. In Nigeria, plasmid-mediated CTX-M1 has recently been reported in 9/25 blood culture isolates of S. typhi from Lagos [75].…”