Metallo beta-lactamases (MBLs) are a group of enzymes produced by certain Gram-negative bacteria that confer resistance to a wide range of beta-lactam antibiotics, including carbapenems. These enzymes require zinc ions for their activity and are capable of hydrolysing many clinically important antibiotics, making infections difficult to treat. The emergence and spread of MBL-producing organisms such as Escherichia coli  represent a serious threat to public health and hospital infection control. Early detection and surveillance of MBL-producing strains are therefore essential to guide appropriate antibiotic therapy and limit their dissemination.

AIM AND OBJECTIVES

• To detect the presence of Metallo beta-lactamase-producing E.Coli among clinical isolates.
• To identify carbapenem-resistant isolates, performing  tests for MBL production, and analysing the prevalence of MBL-producing E.Coli in clinical samples.

MATERIALS AND METHODS

• TYPE OF STUDY: Prospective Observational hospital based study
• NUMBER OF SAMPLES BEING PROCESSED: 100 samples
• PLACE AND DURATION OF STUDY: Department of Microbiology, Muzaffarnagar Medical College & Hospital over a period of 11 months from April 2025 to February 2026.
• INCLUSION CRITERIA: Clinical samples such as urine, blood, sputum, and wound swabs were collected from patients in a Muzaffarnagar medical college.
• EXCLUSION CRITERIA: Including all sample in Lab except stool sample.
• SAMPLE PROCESSING: The isolates were cultured on appropriate media and identified using standard microbiological techniques. Antibiotic susceptibility testing was performed using the Kirby–Bauer disc diffusion method according to CLSI guidelines. Carbapenem-resistant isolates were further screened for MBL production using modified Carba NP test. The results were recorded and analysed to determine the prevalence of MBL-producing strains

RESULTS

Out of the total 100 bacterial isolates obtained, a 50 isolates (E.Coli) showed resistance to carbapenem antibiotics. Among these resistant isolates, 28 were confirmed as MBL producers through Modified Carba NP   testing. These strains exhibited multidrug resistance patterns, limiting treatment options.

Figure:1

Figure: 02

MODIFIED CARBA NP TEST

Fig 3: Age and gender wise distribution of patients

Fig 4: Distribution of Samples

Majority of the Samples was Urine(34.1%) followed by Pus (20.6%), and least number was pleural fluid (8.2%) followed by Blood (17.6%).

Figure 5: RESISTANCE SHOWING TO MEROPENEM, IMIPENEM,IRTAPENEM

Table 1. Distribution of Clinical Samples

DISCUSSION

• The study highlights the increasing occurrence of metallo-beta-lactamase-producing bacteria in clinical settings.
• Early detection through routine screening methods is essential for effective infection control and appropriate antibiotic therapy.
• Continuous monitoring and strict antibiotic stewardship programs are necessary to prevent the spread of these highly resistant pathogens.

CONCLUSION

The Modified Carba NP Test is a rapid, economical, and reliable phenotypic method for detecting carbapenemase-producing E. coli. A high prevalence of MBL-producing isolates was observed in the present study, highlighting the need for routine screening, antimicrobial stewardship, and infection control measures.

LIMITATIONS

The study was conducted at a single center with a relatively small sample size. Molecular characterization of carbapenemase genes was not performed.

REFERENCE

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