Determining the role and impact of insects and spiders in the dissemination of multi-drug resistant pathogens in post-surgical infections from low-middle income countries: a microbiological study

Background: Infection control practices in low middle-income countries (LMIC) are often suboptimal in preventing nosocomial infections with Gram-negative multi-drug resistant bacteria (MDRB); particularly, Enterobacterales (MDRE). Herein, we determined the connectivity of MDRB among post-surgical infections (PSI), hospital surfaces (HS) and spiders/insects (SI) in a LMIC hospital comparing summer and winter.Methods: A comprehensive sampling strategy was applied to include PSI, HS and SI. Anonymised patient data was collected, bacteria were isolated from samples and were fully phenotypically characterised. Samples were plated onto selected growth media and resistance genes screened by PCR. Genotypes, phylogenetic relationships and transmission events between samples from different sources was investigated by whole genome sequencing (WGS) and single nucleotide polymorphisms (SNPs) analysis (< 20 SNPs). Findings: Most samples (>89.5%) grew on selective media and we recovered from PSI, HS and SI, 177, 107 and 549 isolates, respectively. Isolates gave high levels of resistance (>78%) to extended-spectrum cephalosporins and ertapenem. A total of 53 blaNDM, 102 blaCTX-M-15 and 46 blaOXA-48-like positive MDRE were isolated from PSI; 83 blaNDM, 136 blaCTX-M and 20 blaOXA-48-like from HS; and 300 blaNDM, 700 blaCTX-M and 51 blaOXA-48-like from SI. No blaKPC was detected. Most dominant species among all samples were Escherichia coli (14.3%), Klebsiella pneumoniae (10.9%) and Enterobacter cloacae (16.3%). Phylogenetic analysis (<20 core single nucleotide polymorphisms) showed many linkages between PSI, HS and SI samples with Escherichia coli, Enterobacter cloacae and Klebsiella pneumoniae gave 85, 69 and 15 linkages, respectively. E. coli showed the most linkages (n= 39/85), the majority of E. coli linkages occurred between SI and PSI (n=34). Interpretation: This is the first report utilising genomics to unequivocally link SI insects to PSI in LMICs. Our study shows that insects play a critical role in contaminating hospital surfaces and disseminating MDRE and has immense ramifications for infection control policies in LMICs.