METALLO-β-LACTAMASE-PRODUCING CLINICAL ISOLATES OF ACINETOBACTER SPECIES AND PSEUDOMONAS AERUGINOSA FROM INTENSIVE CARE UNIT PATIENTS OF A TERTIARY CARE HOSPITAL

Drug Resistance Mechanism among Acinetobacter Species

Acinetobacter species cause infections that are difficult to control due to multi-drug resistance and are noted for their intrinsic resistance to antibiotics and for their ability to acquire genes encoding resistance for the production of beta-lactamases and Aminoglycoside-modifying enzymes. MBLs are molecular class B and functional group 3 beta-lactamases which have the capability of hydrolyzing all β-lactams except the Monobactam, Aztreonam. Of several MBLs, only IMP, VIM and SIM types have been detected in these species. To analyze the antibiotic resistance patterns among Acinetobacter isolates and to detect Carbapenemase and MBL among MDR Acinetobacter isolates. The descriptive study of all phenotypically identified strains and multidrug-resistant strains of Acinetobacter species was conducted. A total of 303 isolates were isolated from various samples. They were processed and identified by standard Microbiological procedures. The antibiotics susceptibility testing was performed by Kirby- Bauer disc diffusion method using CLSI guidelines. Carbapenemase production was detected by employing 3 phenotypic test methods (MHT, CDM and DDST). Of 6355 samples processed, 303 were found to be Acinetobacter species, among those 50 were multidrug-resistant strains. The highest isolation of MDR Acinetobacter was from endotracheal tube tip (42%) and pus sample (32%). The majority of MDR Acinetobacter infection was found in male patients 36 (72%) compared to female patients 14 (28%). The majority of the strains were isolated from patients >/ 60 years of age group (%). A number of these isolates were more from ICU wards (30%) followed by Surgery wards (24%). Higher resistance for the Piperacillin/tazobactam ((82%), followed by Ceftazidime (80%), Imipenem (76%) etc. and the most susceptible drug was found to be the Tigecycline (82%) followed by Colistin (80%). Carbapenemase production was detected by MHT and 24 (48%) isolates were MHT positive. MBL production was detected by CDM and 34 (68%) isolates were CDM positive and by DDST 30 (60%) isolates were positive. Acinetobacter species are increasingly important nosocomial pathogens and are capable of rapid adaptation to the hospital environment. The variety of potential source of contamination or infection with these species in the hospital environment makes control of outbreaks caused by these difficult.

Surveillance of antibiotic sensitivity pattern in chronic suppurative otitis media of an Indian teaching hospital

INTRODUCTION

Chronic suppurative otitis media (CSOM) is a common problem in worldwide and untreated CSOM leads to fatal complications like facial nerve paralysis, lateral sinus thrombosis, labyrinthitis, meningitis and brain abscess in developing country like India.

OBJECTIVE

To isolate causative bacteria and antibiotic sensitivity pattern for CSOM and to know the prevalence of extended spectrum beta lactamases (ESBL) and Metallobetalactamases (MBL) in CSOM patients.

METHODS

A total of 500 ear swabs of clinical suspected CSOM patients were cultured on specific cultured medium and identified the bacteria with conventional methods. Then all the identified bacteria were subjected with specific antibiotics by the Kirby-Bauer's method to know the resistance pattern of antibiotics. ESBL and MBL strains were detected by double disc diffusion test.

RESULTS

A total of 384 bacteria were isolated from 500 CSOM patients, among them 86 P. aeruginosa (22.40%), 112 Staphylococcus aureus (29.17%), 53 A. baumannii (13.80%), 32 E. aerogenes (18%), 26 C. freundii (6.77%), 24 K. oxytoca (6.25%), 23 P. vulgaris (5.99%), 18 K. pneumoniae (4.69%) and 10 P. mirabilis (2.60%) identified with conventional methods. From antibiotic disc diffusion methods 74.22% ESBL strains and 9.90% MBL strains were documented. Multidrug resistant strains of P. aeruginosa (86/384,22.40%) were more prevalent than those of S. aureus (112/384,29.17%) and other bacteria in ear discharges. Imipenem and vancomicin could control to gram negative bacteria and gram positive bacteria respectively.

CONCLUSION

Continuous and periodic evaluation of microbiological profile and antimicrobial sensitivity pattern of bacterial is essential for optimum management of CSOM patients.