The nexus between resistance determinants, plasmid type, and clonality appears to play a crucial role in the dissemination and survival of carbapenem-resistant Klebsiella pneumoniae (CRKP). The incidence of infections involving CRKP in Saudi Arabia is increasing and there is a need for detailed molecular profiling of this pathogen for CRKP surveillance and control. The resistance determinants of 71 non-redundant CRKP isolates were investigated by polymerase chain reaction (PCR) and sequencing. Plasmid typing was performed using PCR-based replicon typing and the clonality of isolates was determined by multilocus sequence typing. Capsular polysaccharide synthesis genes and other virulence factors were examined using multiplex PCR. Diversity was calculated using DIVEIN, clonal relationship was determined using eBURST, and phylogenetic analysis was performed using SplitsTree4. A polyclonal OXA-48 gene alone was the most common carbapenemase detected in 48/71 (67.6%) isolates followed by NDM-1 alone in 9/71 (12.7%) isolates. Coproduction of OXA-48 and NDM-1 was observed in 6/71 (8.5%) isolates. Both carbapenemase genes could be transferred into an Escherichia coli recipient. CTX-M-15 was the most abundant extended-spectrum β-lactamase gene detected in 47/71 (66.2%) isolates, whereas clone-specific CTX-M-14 (ST-199 and -709) was found in 15/71 (21%) isolates. Sixty-seven of 71 isolates were positive for one or more plasmid replicons. The replicons detected were: IncFII; IncFIIK; IncFIA; IncFIB; L/M; IncI1; and IncN. FIIK and L/M were predominant, with 69 and 67% positivity, respectively. All isolates were negative for the magA (K1), rmpA, and K2 genes and presented a non-hypermucoviscous phenotype. A polyclonal CRKP reservoir of sequence types (STs)-37, − 199, and − 152 was observed and ST-152 appeared to be a “frequent carrier” of the NDM-1 gene. ST-199, a singleton not previously reported, showed a sequence diversity suggestive of positive selection. A significant association was evident between resistance determinants and the clonal types of K. pneumoniae: all ST-152 isolates were positive for NDM-1 but negative for OXA-48; ST-199 isolates were positive for OXA-48 but negative for NDM-1; and ST-709 and -199 isolates were positive for CTX-M-14. The incidence of certain clonal types in large numbers predicts an outbreak-like situation and warrants stringent surveillance and infection control.

Congenital heart defects (CHDs) are the most common types of birth defects, and global incidence of CHDs is on the rise. Despite the prevalence of CHDs, the genetic determinants of the defects are still in the process of being identified. Herein, we report a consanguineous Saudi family with three CHD affected daughters. We used whole exome sequencing (WES) to investigate the genetic cause of CHDs in the affected daughters. We found that all affected individuals were homozygous for a novel splice-altering variant (NM_001330069.1: c.265-1G>T) of PRKD1, which encodes a calcium/calmodulin-dependent protein kinase in the heart. The homozygous variant was found in the affected patients with Pulmonary Stenosis (PS), Truncus Arteriosis (TA), and Atrial Septal Defect (ASD). Based on the family’s pedigree, the variant acts in an autosomal recessive manner, which makes it the second autosomal recessive variant of PRKD1 to be identified with a link to CHDs, while all other previously described variants act dominantly. Interestingly, the father of the affected daughters was also homozygous for the variant, though he was asymptomatic of CHDs himself. Since both of his sisters had CHDs as well, this raises the possibility that the novel PRKD1 variant may undergo autosomal recessive inheritance mode with gender limitation. This finding confirms that CHD can be associated with both dominant and recessive mutations of the PRKD1 gene, and it provides a new insight to genotype–phenotype association between PRKD1 and CHDs. To our knowledge, this is the first report of this specific PRKD1 mutation associated with CHDs.