Klebsiella pneumoniae: A potential food safety risk in wild fruits and dried vegetables in Botswana

Abstract

The bacterium Klebsiella pneumoniae is ubiquitous in nature and is found on the general vegetation and their fruits. The subspecies “pneumonia” is known to cause community-acquired and nosocomial pneumonia in immune-compromised persons (Ko et al., 2002; Yu et al., 2007; Yinnon et al., 1996 and Struve and Krogfelt, 2004). Some the vegetation and wild fruits form part of the staple diet or is consumed as delicacies in Botswana. The potential presence of K. pneumoniae therefore poses a potential food safety hazard given the fact that the gastro-intestinal route is considered one of the major infection routes of K. pneumoniae (Struve and Krogfelt, 2004 and Struve and Krogfelt, 2003). This study sought to evaluate the occurrence of K. pneumoniae in dried vegetables and fruits consumed in Botswana. One representative dried vegetable (morogo wa dinawa) and two representative wild fruits (morula and moretlwa) were selected for the study based on their popularity in the country. The study confirmed the occurrence of K. pneuminioniae on the three foods studied. The isolation rates of the microbe per sample type was 92.3% (morula fruit), 86.4% (morogo wa dinawa) and 86.2 (moretlwa). The overall isolation rate from the three sample types was 89.3%. This showed that there is a significant presence of the microbe on the three foods studied therefore there is a potential food safety risk in consuming these foods by susceptible groups (immune-compromised individuals). The API20E identification system showed five different biotype profiles. The most frequent API20E biotype encountered was 5215773 (44.6%) followed by 5214773 (39.1%). The rest of the biotypes (5215573, 5015773 and 4215773) occurred at a frequency of 2.2%. These biotypes show that there are definite biochemical differences between the isolates. Of the isolates obtained 38% were of the encapsulated phenotype. The highest in-sample occurrence rate of the encapsulated phenotype was in morogo wa dinawa ( 52.6%) followed by moretlwa (40%) and lastly morula (31.3%). Antibiotic susceptibility testing by the disk diffusion method showed that the isolates were most susceptible to 30ug cefotaxime (24.4mm average clearance zone), and totally resistant to 1ug oxacillin and 30ug vancomycin (0.0mm average clearance zone). All of the strains analysed were completely resistant to oxacillin (1ug) and vancomycin (30ug). For cotrimoxazole (25ug), 22.8% of the isolates were completely resistant.