Identification and Characterization of Multidrug Resistant Bacteria from the Gut and the External Surface of Cockroaches (Periplaneta americana) Found within Homes in Abakaliki Metropolis

Abstract

Cockroaches (Periplaneta americana) are one of the important vectors that spread multidrug resistant pathogenic bacteria in environment. We screened the presence of multi-drug-resistant bacteria from cockroaches (n=150) found in homes within Abakaliki metropolis through standard microbiological techniques. Antibiotics susceptibility studies on the isolate were conducted using Kirby-Bauer disc diffusion method with penicillin G, streptomycin, ciprofloxacin, imipenem, trimethoprim-sulfamethoxazole, chloramphenicol, gentamicin, tetracycline, ceftazidime, cefotaxime, amoxicillin-clavulanic acid, ceftriaxone, vancomycin and erythromycin and the results were determined using the Clinical and Laboratory Standards Institute (CLSI) guidelines. Multidrug resistance index of the test bacteria was determined using the formula; MARI = x/y, where x = number of antibiotics to which the test isolate showed resistance and y= total number of antibiotics to which the test isolate has been evaluated or showed sensitivity. The result of this study revealed an occurrence rate of 104(69.3%) bacteria present in the external surface washes of cockroaches. These include Escherichia coli 17(11.3%), Psudomonas aeruginosa 11(7.3%), Klebsiella pneumoniae 9(6%), Salmonella species 28(18.7%), Shigella species 8(5.3%) and S. aureus 31(20.7%) while overall bacteria occurrence rate of 39(26%) was recorded in guts sample of cockroaches which includes Escherichia coli 19(12.7%), Klebsiella pneumoniae 3(2%), Salmonella species12 (8%) and Shigella species5 (3.3%). Antibiotic susceptibility result of the isolates revealed 100% resistance against tetracycline, trimethoprim-sulfamethoxazole, penicillin G and amoxicillin-clavulanic acid while all the other isolates were highly sensitive to imipenem and ciprofloxacin (100%) and ceftazidime (90.9%) respectively. Multidrug resistance index result shows that majority of the isolate were multidrug resistant with a range of 0.4-0.7 recorded against isolates from gut content and surface washed samples of cockroaches. Therefore, infection caused by bacteria isolated from cockroaches in this study may be treated with, ciprofloxacin and ceftazidime while imipenem should be used with caution.