Five-Year Outbreak of Community- and Hospital-Acquired Mycobacterium porcinum Infections Related to Public Water Supplies

Abstract

Mycobacterium porcinum is a rarely encountered rapidly growing Mycobacterium (RGM). We identified M. porcinum from 24 patients at a Galveston university hospital (University of Texas Medical Branch) over a 5-year period. M. porcinum was considered a pathogen in 11 (46%) of 24 infected patients, including 4 patients with community-acquired disease. Retrospective patient data were collected, and water samples were cultured. Molecular analysis of water isolates, clustered clinical isolates, and 15 unrelated control strains of M. porcinum was performed. Among samples of hospital ice and tap water, 63% were positive for RGM, 50% of which were M. porcinum. Among samples of water from the city of Galveston, four of five households (80%) were positive for M. porcinum. By pulsed-field gel electrophoresis (PFGE), 8 of 10 environmental M. porcinum were determined to belong to two closely related clones. A total of 26 of 29 clinical isolates subjected to PFGE (including isolates from all positive patients) were clonal with the water patterns, including patients with communityacquired disease. Fifteen control strains of M. porcinum had unique profiles. Sequencing of hsp65, recA, and rpoB revealed the PFGE outbreak clones to have identical sequences, while unrelated strains exhibited multiple sequence variants. M. porcinum from 22 (92%) of 24 patients were clonal, matched hospital-and household water-acquired isolates, and differed from epidemiologically unrelated strains. M. porcinum can be a drinking water contaminant, serve as a long-term reservoir (years) for patient contamination (especially sputum), and be a source of clinical disease. This study expands concern about public health issues regarding nontuberculous mycobacteria. Multilocus gene sequencing helped define clonal populations.Mycobacterium porcinum, a rapidly growing mycobacterium (RGM), was first isolated in 1973 from lymph nodes of swine with tuberculous-like infection (33). In 1983, it was further characterized and deposited in the American Type Culture Collection (ATCC) as type strain ATCC 33776 (33). The organism was first recognized as a human pathogen in 2004 when it was distinguished from other members of the Mycobacterium fortuitum sorbitol negative third biovariant complex using molecular techniques (29,35). Clinical infections include wound infections, intravascular catheter-related infections, and osteomyelitis. The species has also been recovered from tap water but, to our knowledge, has not been associated with an outbreak or pseudo-outbreak (29). Most case series of RGM published since 2004 only report a small proportion of M. porcinum isolates (14,24,28).A sharp increase in the number of M. porcinum isolates at the University of Texas Medical Branch (UTMB) Clinical Microbiology Laboratory in Galveston, TX, initiated a retrospective evaluation of RGM isolation rates and confirmed a high proportion of these isolates to be M. porcinum (Table 1). The aim of the present study is to characterize the clinical patients and sources of this increasingly ...

Epidemiology of Nontuberculous Mycobacteria in French Polynesia

“…Indeed, M. porcinum has mainly been reported in water supplies in tropical or subtropical areas in the USA (22,23), Iran (24), Brazil (25) and Mexico (26). We report M. porcinum isolates identified in three patients with M. porcinum lung infection according to the ATS criteria (13), which is consistent with other cases reported previously, particularly in subtropical areas such as Texas and Florida, where clonal dissemination was ob- served, particularly through water systems (22,27).…”

A neonate born withMycobacterium cosmeticumbacteraemia

“…In a review of RGM bacteraemia,9 it was found that the use of at least two active antimicrobials for a minimum of 4 weeks, including the removal of any intravascular catheter, leads to resolution of infection in more than 90% of cases. Antimicrobial susceptibilities of M. cosmeticum is only documented in two other reports 1 3. Including our case, M. cosmeticum showed uniform susceptibilities to amikacin, ciprofloxacin, cefoxitin, clarithromycin, imipenem and trimethoprim/sulfamethoxazole.…”

“…This case also coincided with a sharp increase in M. porcinum isolates causing disease at the University of Texas Medical Branch in Galveston, Texas, USA, which was attributed to water contamination during Hurricane Ike 1. Although M. cosmeticum was not isolated from environmental cultures at the time, direct surface cultures from the equipment used during IBT were not collected and cannot be excluded as a source of infection.…”

“…Environmental cultures were also obtained from hospital tap water, ice from patient floor ice machines and tap water from the residences on Galveston Island in Texas. Several environmental cultures were positive for Mycobacterium abscessus and Mycobacterium porcinum , but none of the cultures were positive for M. cosmeticum 1. This latter community-based investigation was part of a larger environmental study after Hurricane Ike in September 2008.…”

Nontuberculous Mycobacteria in Freshwater Fish and Fish Products Intended for Human Consumption

“…Other species closely related to M. fortuitum were also isolated although not distinguished to the species level in most cases (i.e., M. phocaicum/mucogenicum, M. senegalense/houstonense/ conceptionense, M. peregrinum, and M. porcinum). These mycobacterial species have also been described as important facultative pathogens in humans (Brown-Elliott and Amorim et al, 2010;Brown-Elliott et al, 2011;Kim et al, 2012).…”