Prevalence and Characterization of Food-Borne Vibrio parahaemolyticus From African Salad in Southern Nigeria

Abstract

The demand for minimally processed vegetables (African salad) has increased partly due to its inclusion in ready-to-eat foods. Nevertheless, the associated risk of the presence of emergent foodborne pathogens, such as Vibrio parahaemolyticus might be underestimated. The present study was designed to isolate and characterize foodborne V. parahaemolyticus from minimally processed vegetables using culture-based methods and molecular approach. A total of 300 samples were examined from retail outlets between November 2018 and August 2019 from Southern Nigeria. The prevalence of vibrios from the overall samples based on the colonial proliferation of yellow, blue-green and/or green colonies on thiosulfate citrate bile salts sucrose agar was 74/300 (24.6%). An average of two green or blue-green colonies from respective plates was screened for V. parahaemolyticus using analytical profile index (API) 20 NE. Polymerase chain reaction further confirmed the identity of positive V. parahaemolyticus. The counts of V. parahaemolyticus ranged from 1.5 to 1,000 MPN/g. A total of 63 recovered V. parahaemolyticus were characterized further. The resistance profile of the isolates include ampicillin 57/63 (90.5%), cefotaxime 41/63 (65.1%), ceftazidime 30/63 (47.6%), amikacin 32/63 (50.8%), kanamycin 15/63 (23.8%), and oxytetracycline 16/63 (25.4%). The multiple antibiotic index ranged from 0–0.81. The formation of biofilm by the isolates revealed the following: strong formation 15/63 (23.8%), moderate formation 31/63 (49.2%), weak formation 12/63 (19.1%), and no formation 5/63 (7.9%). A total of 63/63 (100%), 9/63 (14.3%), and 20/63 (31.8%) of the isolates harbored the tox R gene, TDH-related hemolysin (trh) and thermostable direct hemolysin (tdh) determinants respectively. The isolates with O2 serogroup were most prevalent via PCR. Isolates that were resistant to tetracycline, kanamycin, and chloramphenicol possessed resistant genes. The presence of multidrug-resistant vibrios in the minimally processed vegetables constitutes a public health risk and thus necessitates continued surveillance.

Vibriosis and its impact on microbiological food safety

“…In recent years, several publications have reported the presence of these bacteria in different types of marine foods around the world. Vibrios potentially pathogenic to humans were recently isolated from seafood in Germany (Vu et al, 2018), from shrimp marketed both in China (Li et al, 2020) and in Mexico (Guardiola-Avila et al, 2020), in aquaculture farms in Bangladesh (Siddique et al, 2021) and even in salads ready for consumption in Nigeria (Igbinosa et al, 2021).…”

Characterization of Vibrio parahaemolyticus isolated from stool specimens of diarrhea patients in Nantong, Jiangsu, China during 2018–2020

“…Most of the isolates in this study exhibited a high level of resistance to ampicillin, cefuroxime, cefepime, piperacillin, and ampicillin/ sulbactam, but sensitive to ciprofloxacin, levofloxacin, trimethoprim-sulfamethoxazole, gentamicin, amikacin, meropenem, and ceftazidime. V. parahaemolyticus isolates are universally resistant to ampicillin according to literatures [3,15,24,25,40,41,44,[49][50][51][52][53]. The bla CARB-17 gene encoding a novel class A carbenicillin-hydrolyzing β-lactamase family of β-lactamase that is responsible for the resistance to penicillin was detected in all tested V. parahaemolyticus isolates [54].…”

“…The bla CARB-17 gene encoding a novel class A carbenicillin-hydrolyzing β-lactamase family of β-lactamase that is responsible for the resistance to penicillin was detected in all tested V. parahaemolyticus isolates [54]. However, the antimicrobial resistance profiles of V. parahaemolyticus might vary in different reports, for instance, 60.3% of V. parahaemolyticus isolates from rearing water samples of shrimp farms in Fujian, China exhibited resistance to gentamicin in the report of Shu Zhao, et al [50], and 50.8% and 47.6% of isolates from African salad samples in Nigeria were resistant to amikacin and ceftazidime in the report of Etinosa O. Igbinosa, et al [3]. No matter how different of the antimicrobial resistance profiles, emergence of multi-drug resistant V. parahaemolyticus is a serious threat to aquaculture and public health.…”

“…Vibrio parahaemolyticus, a Gram-negative, highly motile, halophilic bacterium, is naturally found in marine ecosystems [1]. This bacterium is the leading cause of seafood-associated gastroenteritis in many countries including China [2][3][4][5]. Human infections with V. parahaemolyticus are usually caused by consumption of raw or undercooked seafood [6].…”

Processed ready-to-eat (RTE) foods sold in Yenagoa Nigeria were colonized by diarrheagenic Escherichia coli which constitute a probable hazard to human health

“…coli O157:H7, Salmonella , Vibrio , Shigella , Clostridium spp. and Staphylococcus aureus have been isolated from fresh-cut ready to eat fruits, vegetables and RTE foods sold on the streets, markets, bukaterian, cafeterias, schools, major cities and fast-food restaurants in Nigeria [ 7 , 23 – 25 ]. Nigeria, being the most populated country in sub-Saharan Africa, is currently faced with FBD problems usually not reported except in cases of outbreaks.…”