Analysis of β-lactamase phenotypes and carriage of selected β-lactamase genes among Escherichia coli strains obtained from Kenyan patients during an 18-year period

Abstract

BackgroundAlthough β-lactam antibiotics are heavily used in many developing countries, the diversity of β-lactamase genes (bla) is poorly understood. We screened for major β-lactamase phenotypes and diversity of bla genes among 912 E. coli strains isolated from clinical samples obtained between 1992 and 2010 from hospitalized and non-hospitalized patients.ResultsNone of the isolates was resistant to carbapenems but 30% of all isolates were susceptible to cefepime, cephamycins and piperacillin-tazobactam. Narrow spectrum β-lactamase (NSBL) phenotype was observed in 278 (30%) isolates that contained blaTEM-1 (54%) or blaSHV-1 (35%) or both (11%). Extended Spectrum β-lactamase (ESBL) phenotype was detected in 247 (27%) isolates which carried blaCTX-M-14 (29%), blaCTX-M-15 (24%), blaCTX-M-9 (2%), blaCTX-M-8 (4%), blaCTX-M-3 (11%), blaCTX-M-1 (6%), blaSHV-5 (3%), blaSHV-12 (5%), and blaTEM-52 (16%). Complex Mutant TEM-like (CMT) phenotype was detected in 220 (24%) isolates which carried blaTEM-125 (29%), while blaTEM-50, blaTEM-78, blaTEM-109, blaTEM −152 and blaTEM-158 were detected in lower frequencies of between 7% and 11%. Majority of isolates producing a combination of CTX-M-15 + OXA-1 + TEM-1 exhibited resistance phenotypes barely indistinguishable from those of CMT-producers. Although 73 (8%) isolates exhibited Inhibitor Resistant TEM-like (IRT) phenotype, blaTEM-103 was the only true IRT-encoding gene identified in 18 (25%) of strains with this phenotype while the rest produced a combination of TEM-1 + OXA-1. The pAmpCs-like phenotype was observed in 94 (10%) isolates of which 77 (82%) carried blaCMY-2 while 18% contained blaCMY-1.Isolates from urine accounted for 53%, 53%, 74% and 72% of strains exhibiting complex phenotypes such as IRT, ESBL, CMT or pAmpC respectively. On the contrary, 55% isolates from stool exhibited the relatively more susceptible NSBL-like phenotype. All the phenotypes, and majority of the bla genes, were detected both in isolates from hospitalized and non-hospitalized patients but complex phenotypes were particularly common among strains obtained between 2000 and 2010 from urine of hospitalized patients.ConclusionsThe phenotypes and diversity of bla genes in E. coli strains implicated in clinical infections in non-hospitalized and hospitalized patients in Kenya is worryingly high. In order to preserve the efficacy of β-lactam antibiotics, culture and susceptibility data should guide therapy and surveillance studies for β-lactamase-producers in developing countries should be launched.

Characterisation of extended-spectrum β-lactamases among Klebsiella pneumoniae isolates causing bacteraemia and urinary tract infection in Mozambique

“…Although ESBLs have been previously reported in sub-Saharan Africa [5][6][7][27][28][29][30], the report of ESBLs in a rural hospital with limited access to third-generation cephalosporins, such as in Manhiça, Mozambique, is relevant, suggesting again the coselection of antibiotic resistance genes. Despite access to thirdgeneration cephalosporins being limited in this community, a high prevalence of b-lactamase genes, such as bla TEM-like and bla OXA-like , has been reported in Shigella and Salmonella isolates in previous studies, reflecting of the high use of ampicillin in the area [23].…”

“…In another sub-Saharan country (Ethiopia), a high level of ESBL-producers (36%; 46% among inpatients and 33% among outpatients) was reported among E. coli strains from different samples (urine, sputum, stool, wound swabs) [28]. Similarly, ESBLs were found in 247 (27%) of 912 E. coli isolates, mainly bla CTX-M-14 (29%) and bla CTX-M-15 (24%), in hospital-and community-acquired infections in Kenya, whilst non-ESBLs were found in 30% (54% bla TEM-1 , 35% bla SHV-1 and 11% both bla TEM-1 and bla SHV ) [29]. ESBLs have also been detected in Gabon, where 49.4% of all K. pneumoniae were ESBL-producers [7].…”

Detection of blaCTX-M-type genes in complex class 1 integrons carried by Enterobacteriaceae isolated from retail chicken meat in Brazil

“…Although the predominant ESBL families have been TEM, SHV and CTX-M (Bush and Jacoby, 2010), in the last years, the incidence of the CTX-M-type has risen dramatically (Wellington et al, 2013). In fact, currently the CTX-M-2, CTX-M-8 and CTX-M-15 variants are widely disseminated all over the world within Enterobacteriaceae from humans and animals, and their potential transmission by contaminated food, mainly chicken meat, has been highlighted (Egervärn et al, 2014;Kawamura et al, 2014;Kiiru et al, 2012). These enzymes are encoded by bla CTX-M -type gene associated with mobile genetic elements, including insertion sequences ISEcp1 type and ISCR1, most carried on transferable plasmids (Zhao and Hu, 2013).…”

Prevalence of CTX-M beta-Lactamases in Escherichia coli from community-acquired urinary tract infections and associated risk factors among women in Cameroon

“…[5] There is paucity of reports on ESBL in E. coli strains in community-acquired UTIs in developing countries. [2,[6][7][8] Few studies have been done on ESBL however they only looked at intestinal carriage. [9][10][11] The prevalence of CTX-M in E. coli strains responsible for community-acquired UTI in Cameroon or Central Africa has not been documented.…”