**5. Conclusions**

A two-year study of *L. pneumophila* populations in water and biofilms in the drinking water distribution systems (DWDS) of eight hospitals across the West Bank demonstrated low and rare abundance of culturable *L. pneumophila* in water, but substantially higher prevalence in biofilm. PCR-based analyses consistently showed a higher detection rate in water and biofilm. Based on high resolution MLVA-8(12) genotyping, the 180 isolates retrieved in the West Bank could be characterized as a rather diverse population, with four clonal complexes (VACC). Most of the genotypes (20 out of 27) were unique, and so far, have only been described for the West Bank, including those forming a new clonal complex (VACC11). In addition, seven genotypes were also observed outside of the West Bank, including two genotypes of worldwide abundance, i.e., Gt 4(17) comprising *L. pneumophila* strain Paris, and Gt 64(74) comprising strain Philadelphia-1. The observed uniqueness of the genotypes and the variability from site to site were attributed to individual groundwater-based water supplies. In addition, the isolated strains seemed to be of high health relevance, especially strains of VACC1 and VACC11. MLVA-genotyping was shown to be highly consistent with SBT but showed a higher resolution. Since the most health relevant ST1 (VACC1) and ST461 (VACC11) strains could be further distinguished into several MLVA-genotypes, MLVA-genotyping could provide an excellent basis for future source tracking in the West Bank. MLVA-genotyping provides an adequate resolution, and thus, a good basis for detailed studies of the health- and water-management-relevant traits of *L. pneumophila* [42,81,83,86] in support of a better clinical and DWDS managemen<sup>t</sup> in the West Bank.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2076-0817/9/11/862/s1, Table S1. List of *L. pneumophila* strains (n = 180) isolated from the West Bank analyzed in this study, MLVA-8(12) Figure S1: Sampling map of the eight hospitals and Al-Quds University in the West Bank. Figure S2: UPGMA *Pathogens* **2020**, *9*, 862

based clustering analysis of the MLVA-8(12) profiles of 180 *L. pneumophila* strains isolated from water and biofilm samples of the Al-Quds University campus and eight hospitals of the West Bank.

**Author Contributions:** A.R.Z. performed sample acquisition and analysis, strain isolation, data analysis and contributed to drafting of the manuscript. I.B., M.G.H., M.S. and D.M.B. designed the work, contributed to data evaluation and wrote the manuscript. M.P., A.S., H.A., S.B., and R.L. contributed to sampling, and sample and strain analysis. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by DFG gran<sup>t</sup> (HO 930/5-1&2) and the Hildegard-Elisabeth Foundation.

**Acknowledgments:** We thank the administration of the hospitals for allowing us to collect the samples. We thank the Palestinian Water Authority (PWA) for helpful support, information and data. We are grateful to Dalia Abu Hilal, Verena Maiberg and Josefin Koch for technical assistance. Christian Lück of the TU Dresden kindly provided the Sequence Types of the isolates.

**Conflicts of Interest:** The authors declare no conflict of interest.
