The usefulness of Neisseria gonorrhoeae strain typing by Pulse-Field Gel Electrophoresis (PFGE) and DNA detection as the forensic evidence in child sexual abuse cases: a case series

The role of legal medicine professionals in preventing pregnancy and sexually transmitted infections among female victims of sexual assault

Sexual violence can have an overwhelming impact on the victim's physical and mental health; the consequences include unintended pregnancy and sexually transmitted infections (STIs). Therefore, the examiners must assess victims for possible pregnancy and sexually transmitted infections as a part of the sexual assault examination. This article aims to orient the medico-legal examiners towards their role in preventing unintended pregnancy and sexually transmitted infections among victims of sexual assault. Prompt detection of pregnancy or STIs is critical, as any delay would adversely affect the successful administration of emergency contraception and post-exposure prophylaxis (PEP) against human immunodeficiency virus (HIV) and other sexually transmitted infections.

Whole-genome sequencing of Neisseria gonorrhoeae in a forensic transmission case

Molecular epidemiology and phylogenetic analyses are frequently used in the investigation of viral transmission cases in forensic contexts. Here, we present the methods and results of the analysis of a bacterial transmission episode in an alleged child abuse case using complete genome sequences obtained by high-throughput sequencing (HTS) methods. We obtained genomes of Neisseria gonorrhoeae from the victim, the suspect, and 29 unrelated controls. The analysis of the genomes revealed that the victim and suspect isolates had identical sequences in both the bacterial chromosome and the single plasmid present in them. One of the local controls was very similar (differing in only 2 SNPs) to the case sequences, but the remaining controls were very divergent. Additional cases of identity and very high similarity among controls were observed occasionally, pointing at recent transmission cases. These results were more discriminative than the previous molecular epidemiology analyses performed at the hospital's Microbiology Service, as Multi-Locus Sequence Typing (MLST) could not distinguish between the suspect/victim and the controls isolates, and Pulse Field Gel Electrophoresis (PFGE) was not able to distinguish between the suspect/victim and one of the local controls. These results lead us to conclude that complete bacterial genome sequences obtained with HTS technologies may be a valuable tool for establishing recent transmission cases and, although more studies are needed, they have a great potential for being used in forensic analyses.

The use of current genotyping assay methods for Neisseria gonorrhoeae

The review deals with up-to-date genotyping assay methods of Neisseria gonorrhoeae. The review covers the characteristics and features of each method, application areas of genotyping assay of Neisseria gonorrhoeae. The methods described enable to upgrade the diagnostication of gonococcal infection, predict its antibiotic resistance, trace the contagion and channels of the infection as well as study the processes of molecular evolution of the microorganism. Information obtained based on up-to-date N. gonorrhoeae genotyping assay methods can be used in developing the reproductive health strategy of the population.

Molecular epidemiology of Neisseria gonorrhoeae using multi-antigen sequence typing and pulse-field gel electrophoresis in highly endemic Western Australian populations

Background

The remote and indigenous populations of Western Australia (WA) have one of the highest notification rates of gonorrhoea in the world. Despite this, the low rate of antimicrobial resistance in Neisseria gonorrhoeae from these regions permits the use of amoxycillin as empirical therapy. We describe the first molecular epidemiological study of gonococci isolated from this population using two different typing platforms.

Methods

Pulse-field gel electrophoresis (PFGE), Neisseria gonorrhoeae multi-antigen sequence typing (NG-MAST) and antimicrobial susceptibility tests were performed on 128 consecutive N. gonorrhoeae isolates cultured between January 2011 and December 2013. To highlight clusters isolates were evaluated based on their tbpB sequence types.

Results

No predominant NG-MAST or PFGE types were found. A total of 67 distinct PFGE pulsotypes were identified amongst the 128 isolates in this study with 20 PFGE pulsotypes representing 78 isolates. A total of 59 NG-MAST sequence types were found, represented by 45 porB alleles and 28 tbpB alleles with 13 tbpB genomogroups from 45 NG-MAST sequence types. TbpB genomogroup 29, represented by 45 isolates, was by far the most common genomogroup overall.

Conclusions

Results from this study suggest that gonococcal epidemiology in WA is quite different between remote regions and major population centres and, in some cases, geographically restricted. It is likely that isolates originating from endemic regions of WA mostly represent independent, small sexual networks with an infrequent interchange between other communities and regions. Given the high rate of antimicrobial resistance elsewhere in Australia, ongoing surveillance is essential to ensure the enduring efficacy of amoxycillin empiric use in the remote regions of WA.