Pseudo-Outbreak of Cupriavidus pauculus Infection at an Outpatient Clinic Related to Rinsing Culturette Swabs in Tap Water

Abstract

Cupriavidus pauculus is a water microorganism rarely isolated from clinical specimens. We describe a pseudo-outbreak in which multiple strains that were associated with moistening of culturette swabs with tap water were isolated from a single clinic before collecting the patient specimen. CASE REPORTIn a period of 6 weeks, 27 skin and superficial site swab specimens were submitted from an outpatient clinic to the clinical microbiology laboratory for bacterial culture. The specimens were plated onto blood agar (BA; Becton Dickinson, MD), MacConkey (Becton Dickinson, MD), and chocolate agar (CA; Becton Dickinson, MD) per routine procedure. Eleven of the clinical specimens grew an unusual bacterium. After 24 h, the colonies were smooth, round, and colorless on BA and CA and nonfermentative on MacConkey agar. The cultures were negative for common skin flora, such as coagulase negative Staphylococcus or Corynebacterium spp., and other commonly isolated wound pathogens, such as Staphylococcus aureus or Pseudomonas aeruginosa (6). The organisms were found to be Gram negative and catalase and oxidase positive and were reported as "Pseudomonas-like" nonfermenting bacilli by the MicroScan WalkAway system (Siemens Healthcare Diagnostics, IL).Because of the uncommon nature and the presence of this bacterium in multiple specimens in a short span of time, further investigation was undertaken. All the specimens originated from a single hospital-affiliated outpatient clinic and were submitted by the same physician's office. The swab specimens had been collected with double culturette swabs (BBL CultureSwab; BD Diagnostics, Sparks, MD) from various skin and wound sites from patients with various comorbidities and of different age groups. The clinic was contacted, and unopened culturette swabs of the same lot number were requested to rule out contamination. The uninoculated culturettes plated onto BA, CA, MacConkey, and colistin nalidixic acid (CNA; Remel, KS) plates did not yield any growth, thereby ruling out contamination. The clinic was contacted again for a detailed account of specimen collection methods. Upon further inquiries, it was discovered that the culturette swabs were moistened with tap water before collecting the patient specimen. A tap water sample from the clinic sink was requested and plated onto BA, CA, MacConkey, and CNA plates by using a swab, and it grew a "Pseudomonas-like" nonfermenting bacilli morphologically similar to the patient isolates.A total of six isolates and the water isolate were separately referred to the Ohio Department of Health Laboratory and to the Centers for Disease Control and Prevention (CDC) reference laboratories for further identification. The isolates were identified as Cupriavidus (Ralstonia, Wautersia) pauculus based on morphology and biochemical tests. The following tests were reported positive: oxidase, catalase, citrate, and urea. The following were negative: indole, nitrate, methyl red-VogesProskauer, gelatin, and esculin. There was no acid production from glucose, xylose, ma...

Investigation of a Candida guilliermondii Pseudo-outbreak Reveals a Novel Source of Laboratory Contamination

“…Pseudo-outbreaks caused by bacterial, fungal, and viral pathogens are well documented and have been traced to a variety of sources, including contaminated medical or laboratory equipment, tap water rinsing, use of nonsterile solutions in the microbiology laboratory, and specimen cross-contamination (4,(7)(8)(9)(10)(11)(12)(13). They have also been traced to highly contaminated environments, such as drinking water and ice machines (14,15), which may introduce microorganisms into patients or clinical specimens during collection.…”

First case of pneumonia caused by Cupriavidus pauculus in an infant in the Gulf Cooperation Council

“…Cupriavidus pauculus was previously classified as CDC group IV c-2, Ralstonia paucula and then as Wautersia paucula [1,8]. It is a ubiquitous environmental organism found mainly in soil, water, and on plants [1,2,8].…”

“…It is a ubiquitous environmental organism found mainly in soil, water, and on plants [1,2,8]. C. pauculus is a Gram-negative, motile, aerobic, non-spore-forming rod bacteria.…”

“…Examples of the source of contamination include nebulization solutions, tap water, hydrotherapy pools, and bottled mineral water [5,8,10]. In addition, medical devices, such as extracorporeal membrane oxygenation (ECMO) equipment and ventilators, have been reported to be a source of contamination [5,9,10].…”

Assessment of copper and zinc salts as selectors of antibiotic resistance in Gram-negative bacteria

“…Resistance to sulfamethoxazole/trimethoprim (SXT), tetracycline (TET) and ceftazidime (CEF) was only recovered from Zn-enriched cultures and all the isolates recovered from Cu-enriched cultures were resistant to meropenem (MER). Betaproteobacteria or Flavobacteriia are widespread in water habitats and recognized opportunistic pathogens (Balada-Llasat et al, 2010;Coenye et al, 2003;Frank et al, 2013;Ryan et al, 2006). Some of the isolates recovered from the metal-enrichment cultures (e.g.…”