Phenotypic Detection Of Extended Spectrum Beta Lactamases Producing Organism Among Godfrey Okoye University Students

1.4.1.4 Southern Africa

In South Africa, class A and D ESBLs and pAmpC were present, and the prevalence ranged from 8.8 to 13.1% in hospitals and was 0.3 and 4.7% in two communities (Chunderikaet al, 2008).

1.4.1.5 Western Africa

In Ghana and Mali, class A ESBLs were found in 49.4 and 63.4–96%, respectively, in hospital and community samples (Bougoudogoet al, 2009).

In Niger, 40% of hospital samples carried class A ESBLs or pAmpC (Andremontet al, 2011).

In Senegal, class A and D ESBLs were found in 10% of community stool samples. (Andremontet al, 2009)

1.4.1.6NIGERIA (West Africa)

In Nigeria, class A and D ESBLs and pAmpC were found in hospital settings, and the prevalence ranged from 10.3 to 27.5% (Aibinuet al, 2012). In a mixed sample from a hospital and a community, the prevalence was 11.7%. (Afunwaet al, 2011)

In Nigeria, an ESBL prevalence of 9.25% was recorded in a study conducted to screen for ESBLs production among isolates of Enterobacteriaceae (Aliyuet al, 2010). 

In another study conducted in a tertiary health center in Nigeria to determine ESBL prevalence in Escherichia coli and Klebsiella Species; an ESBL prevalence of 2.5% for Escherichia coli and 5% for Klebsiellapneumoniae were recorded (Aboderin and Olowe, 2010).

1.5 PHENOTYPIC IDENTIFICATION OF ESBL

Extended-spectrum β-lactamase (ESBL) detection tests should accurately discriminate between bacteria producing these enzymes and those with other mechanisms of resistance to β-lactams, e.g., broad-spectrum β-lactamases, inhibitor-resistant β-lactamases and cephalosporinase overproduction. Several phenotypic detection tests, based on the synergy between a third-generation cephalosporin and clavulanate, have been designed: the double-disk synergy test (DDST), ESBL E-tests, and the combination disk method. These tests often need to be refined in order for them to detect an ESBL in some bacterial strains, such as those that also overproduce a cephalosporinase. The sensitivity of the DDST can be improved by reducing the distance between the disks of cephalosporins and clavulanate. The use of cefepime, a fourth-generation cephalosporin that is less rapidly inactivated by cephalosporinase than by ESBL, improves the detection of synergy with clavulanate when there is simultaneous stable hyperproduction of a cephalosporinase; alternatively, the cephalosporinase can be inactivated by performing phenotypic tests on a cloxacillin-containing agar. Some β-lactamases can hydrolyze both third-generation cephalosporins and carbapenems, such as the metallo-β-lactamases, which are not inhibited by clavulanate, but rather by Ethylenediaminetetraacetic acid (EDTA). The production of an ESBL masked by a metallo-β-lactamase can be detected by means of double inhibition by EDTA and clavulanate. Since extended-spectrum Ambler class D oxacillinases are weakly inhibited by clavulanate and not inhibited by EDTA, their detection is difficult in the routine laboratory (Danish et al 2015).