Detection of Extended-Spectrum β-lactamase and Amp-C β-lactamase among Bacteria Isolated from Patients in Some Hospitals in Khartoum State

Abstract

Production of β-lactamase enzymes by Gram-negative bacteria is the most common mechanism to acquire drug resistance to β-lactam antibiotics. Limitations in detecting extended spectrum β-lactamases (ESBL) and Amp-C β-lactamases have contributed to the uncontrolled spread of bacterial resistance and are of significant clinical concern. This study was conducted to detect extended spectrum β-lactamase (ESBL) and Amp-C β-lactamase among pathogenic bacteria. A Total of 100 clinical specimens (74 urine and 26 wound swab) were collected from patients in Omdurman Teaching Hospital, Asia Hospital and Omer Sawy Military Hospital. These specimens were collected from both males and females. The age of patients was ranged from 10-95 years. The specimens were cultured on MacConky agar, Blood agar and cysteine lactose electrolyte deficiency (CLED) agar. The isolates were identified by colonial morphology, Gram stain and biochemical tests. Isolated bacteria were subjected to antimicrobial sensitivity test. The phenotypic test double disc synergy was used to detect ESBLs, while the disc approximate test used to detect Amp-C enzyme. Fifty-eight (58%) of specimens gave bacterial growth, while )42(% specimens showed no bacterial growth. 58 of bacteria isolated were identified. Urine was the major source of the bacterial isolates 42(72.41%), comprising of the wound swabs 16(27.59%). The most common frequent isolates were Klebsiella pneumoniae 26 (44.8%), followed by Escherichia coli 14(24.1%), Proteus spp 11(19%), Pseudomonas aeruginosa 6(10.3%) and Citrobacter spp1(1.8%). The result of sensitivity test revealed that 45 (77.6%) of isolated were resistant to ceftazidime. Only 10(17.2%) of the isolates were ESBLs positive. These were 5(8,6) Klebsiella pneumoniae, 3(5,2%) Escherichia coli and 2(3.4%) Proteus spp. Only 4 (6.9%) of isolates were Amp-C β-lactamase positive. These were 2(3.4%) Pseudomonas aeruginosa, 1(1.8%) Klebsiella pneumoniae and 1(1.8%) Proteus spp. The association between ESBL producer organisms and gender was found statistically insignificant (p.value = 0.635), while the association between Amp-C β-lactamase producers and gender was found statistically significant (p. value = 0.03). The association between ESBL producer organisms and age groups was found statistically insignificant (p. value = 0.09), while the association between Amp-C β-lactamase producer and age groups was found statistically significant (p. value = 0.04). This study concluded that there is high ratio of ESBLs producers in hospitals and the most producer was Klebsiella pneumoniae. Advanced technique such as PCR test for detection of ESBL and Amp-C β-lactamase is required to confirm the results of this study. Use of antibiotic should be controlled in hospitals and prevention of disease by measures other than the use of antibiotics to reduce antibiotic resistance.