Multi-drug resistant gram-negative bacilli isolated from cockroaches in different environments in Lebanon

Abstract

Cockroaches are one of the most significant and objectionable pests found in apartments, homes, food handling establishments, hospitals, and health care facilities worldwide. Environment, animals, and insects are regarded as major reservoirs of resistance. The aim of this study is to evaluate the extent of spread of Gram-negative MDR organism in cockroaches collected from hospital and community settings in Lebanon.Over a period of 4 months, between August and November 2017, 48 cockroaches were collected from different environments and hospitals in Lebanon. A total of 30 cockroaches were collected from the environment, distributed as 16 cockroaches from the southern region, 11 from Keserwan district, and 3 from the northern region. Whereas, 18 cockroaches in total were collected from 2 hospitals, 12 from a hospital located in the southern region, and 6 from a hospital located in the northern region. Each cockroach was tested for the inner and outer carriage of mutli-drug resistant Gram-negative bacilli.Selective media supplemented with 3 different antibiotics separately, were used for the preliminary screening of antibiotic resistant Gram-negative bacilli. Phenotypic and genotypic detection of resistance including all ESBL and AmpC genes were conducted. The minimum inhibitory concentrations of Colistin against all isolates were determined and mcr-1 gene was detected using PCR. Seventy-two cefotaxime resistant isolates and five colistin resistant isolates were isolated. Escherichia coli was the most isolated species, followed by Serratia marcescens, Klebsiella pneumoniae, and other bacterial species. Nighty eight percent of the isolates obtained showed a multi-drug resistant profile by antibiotic susceptibility testing. The PCR results against ESBL and AmpC genes showed that out of the 72 cefotaxime resistant isolates, 41 isolates harbored the CTX-M gene, 27 harbored the TEM gene, 25 harbored the SHV gene, 6 harbored the OXA gene, 4 harbored the CMY gene, 2 harbore the EBC gene, and 2 harbored the DHA gene. Broth microdilution results showed that 7 isolates were colistin resistant with minimum inhibitory concentrations ranging between 4 μg/ml and 32 μg/ml. These isolates were negative for mcr-1 gene. The prevalence of MDR Gram-negative bacilli on the cockroachs cuticle and in their intestines is alarming since it may make cockroaches as a potential vector of MDR Gram-negative bacilli. Regular spraying of pesticides must be an obligation for safety controls and to control the possible spread of MDR Gram-Negative bacilli.