Nosocomial Outbreak of Drug-Resistant Streptococcus pneumoniae Serotype 9V in an Adult Respiratory Medicine Ward

Abstract

Streptococcus pneumoniae infections arising in hospitalized patients are often assumed to be sporadic and linked to community acquisition. Here, whole-genome sequencing was used to demonstrate nosocomial acquisition of antimicrobial-resistant sequence type 156 (ST156) serotype 9V S. pneumoniae in 3 respiratory patients that resulted in two bacteremias and one lower respiratory tract infection. Two of the cases arose in patients who had recently been discharged from the hospital and were readmitted from the community. Nosocomial spread was suspected solely because of the highly unusual resistance pattern and case presentations within 24 h of one another. The outbreak highlights the potential for rapid transmission and the short incubation period in the respiratory ward setting.

Streptococcus pneumoniae outbreaks and implications for transmission and control: a systematic review

“…Thirteen reports were published from 1916 to 1946, and the remainder were published after 1980. Unique outbreaks by disease syndrome were as follows; 80 lower respiratory tract infection [ 12 – 97 ], 9 conjunctivitis [ 98 – 105 ], 3 otitis media [ 106 , 107 ], 1 surgical site infection [ 108 ], and 1 lower respiratory tract infection and otitis media [ 109 ] (Fig. 1 ).…”

“…No non-susceptibility was reported for cefotaxime ( n = 3) and vancomycin ( n = 2). Twelve studies assessed whether case-patients had ever received either pneumococcal vaccine before the outbreak [ 62 , 66 , 67 , 71 , 73 , 74 , 82 , 88 , 89 , 91 , 93 , 97 ]. Of the studies that provided enough information to calculate vaccination coverage of the source population of cases, two reported 0% coverage [ 66 , 88 ], one reported 7% [ 89 ], and one reported 57% [ 93 ].…”

“…Of the studies that provided enough information to calculate vaccination coverage of the source population of cases, two reported 0% coverage [ 66 , 88 ], one reported 7% [ 89 ], and one reported 57% [ 93 ]. At least one vaccine failure was reported for 6 studies [ 71 , 74 , 88 , 91 , 93 , 97 ]. Two reports described one case-patient vaccine failure of a vaccine received within five years of the outbreak [ 71 , 74 ].…”

“…In the reviewed outbreak articles, we found evidence for multiple modes of transmission. Aside from transmission attributable to nasopharyngeal carriers, there were pneumococcal lower respiratory tract infection outbreaks suggestive of device-associated transmission (infant resuscitation device [ 30 ]; inhaler [ 50 , 97 ]), and infection transmission without any carriers detected [ 27 , 28 , 33 , 39 , 46 , 65 , 97 ]. While it is near impossible to ever fully rule out transient nasopharyngeal colonization as the source, these outbreaks found no evidence that carriers contributed to transmission.…”

“…environment or hand contamination) transmission may also have occurred, because having a roommate with conjunctivitis was associated with developing conjunctivitis [ 101 ]. In four outbreaks, time from exposure to infection in several outbreaks was less 72 hours for at least one case-patient [ 27 , 28 , 65 , 97 ]. Serotype 1, 5, and 9 V exhibited short times between exposure and disease.…”