A Rapidly Fatal Infection with Haemophilus Influenzae Serotype

Open Forum Infectious Diseases ID CASES

A Rapidly Fatal Infection With colonies on chocolate agar. However, there was no growth on sheep’s blood or MacConkey agars. Over the next 48 hours, Haemophilus influenzae Serotype E her temperature and PBS rose to 108.7°F and 8, respectively. Harboring blaROB-1: The Dilemma She developed shock and multiorgan failure. The organism of Safe De-escalation in the Setting was identified as a β-lactamase-producing Haemophilus influenzae (HI), and de-escalation to ampicillin-sulbactam, or cef- of Potential Extended-Spectrum triaxone, or piperacillin-tazobactam was debated. Due to the β-Lactamase Production fulminant nature of her presentation, the possibility of high-

John Hanna,1 Yetunde Ogunsesan,1 Erik Snesrud,3 Rosslyn Maybank,3 er-level resistance to β-lactams, and the fear of possibly induc- Downloaded from https://academic.oup.com/ofid/article/5/12/ofy302/5173656 by guest on 01 October 2021 3 3 3 3 2 Ana Ong, Yoon Kwak, Anthony Jones, Patrick McGann, and Emil Lesho ing further extended spectrum β-lactamase resistance by using 1 2 Internal Medicine Residency Program and Infectious Diseases Unit, Rochester Regional ceftriaxone [1, 2], cefepime was continued until susceptibilities Health, New York; 3Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, Maryland could be confirmed. Four days after admission, numerous sep- Keywords. fatal infection; Haemophilus influenzae tic brain emboli occurred, and she died before susceptibility serotype E; whole-genome sequencing. information became available. Using microbroth dilution and/or disk diffusion tests pre- pared according to Clinical Laboratory Standards Institute CASE methods and interpretative breakpoints, the isolate was resistant A 66-year-old female with asthma-chronic obstructive lung to penicillin and ampicillin, intermediate to amoxicillin-clavu- disease overlap syndrome (ACOS) and rheumatoid arth- lanate and piperacillin-tazobactam, and susceptible to azith- ritis (RA) presented with respiratory distress, altered men- romycin, cefepime, and ceftriaxone. Phylogenetic analysis and tal status, and sepsis. Her family reported no sick contacts, antibiotic resistance gene content, based on its whole genome recent travel, pets, or other epidemiological exposures, and sequence (WGS), revealed that the isolate was serotype E and she had been feeling well, with no fevers, chills, or respira- sequence type 966. It was most closely related to isolates from tory symptoms. Her RA did not require treatment with bio- the Netherlands and Italy, but it was distinct from a large out- logic response modifiers, prednisone, or methotrexate, and break at a military base in Fort Benning, Georgia (Figure 1). The there was no evidence of pulmonary involvement. She was isolate contained blaROB-1, a β-lactamase-encoding gene, and 66 not continuously oxygen dependent, but she was using 2L putative virulence-associated genes. Amino acid mutations intermittently immediately before admission. In the preced- S130G and R244K, which have been shown to confer resistance ing 5 years, she visited the emergency department once and to some extended spectrum cephalosporins and β-lactamase was admitted once for her ACOS. inhibitors [1], were also present. Upon admission, she required urgent endotracheal intu- DISCUSSION bation and was empirically treated with ampicillin, cefepime, vancomycin, azithromycin, and oseltamivir. Her Charlson We describe an interesting isolate and a noteworthy clinical Comorbidity Index (CCI), Pitt Bacteremia (PBS), and outcome. The isolate is notable for its resistance and virulence Simplified Acute Physiology Scores were 4, 3, and 77, respec- gene content, phenotypic susceptibility, and the challenges tively. Chest x-ray showed consolidation of her right lung. encountered during antibiotic susceptibility testing (AST). The Gram-stain of her sputum revealed pleomorphic Gram- patient’s course is remarkable for its fulminance in someone negative coccobacilli. A multiplexed polymerase chain reac- not substantially immunocompromised, nor at the extremes tion respiratory viral panel was negative. Blood and sputum of age. Indeed, her initial CCI between 3 and 4 predicted a cultures grew nonhemolytic, slightly opaque, dome-shaped 10-year survival of 50%–70%. However, before the special test media could be acquired by the hospital laboratory, the patient had died. This emphasizes the value of having local antibio-

Received 17 September 2018; editorial decision 6 November 2018; accepted 7 November 2018. grams available to guide empiric treatment. In addition, having Correspondence: E. Lesho, DO, 1425 Portland Ave., Rochester, NY 14621 ([email protected]). the AST for the specific isolate available would have fostered Open Forum Infectious Diseases® stewardship by informing us that it would have been safe to Published by Oxford University Press on behalf of Infectious Diseases Society of America 2018. This work is written by (a) US Government employee(s) and is in the public domain in the US. de-escalate to ceftriaxone. Given the presence of β-lactamase DOI: 10.1093/ofid/ofy302 production, and a gene with mutations that encode resistance

ID CASES • OFID • 1 H influenze 2842STDY5882019 (Netherlands)

H. influenzae 2842STDY5882040 (Netherlands)

H. influenzae 2842STDY5882041 (Netherlands)

H. influenzae H8072559 (Rochester) Downloaded from https://academic.oup.com/ofid/article/5/12/ofy302/5173656 by guest on 01 October 2021

H. influenzae hi467 (Italy) 0.09

Figure 1. Dendrogram of Haemophilus influenzae from fatal infection. Core genome dendrogram H influenza from this report (red text) and related H influenzae genomes from GenBank (black text). Branch lengths are indicative of strain relationships.

to extended-spectrum β-lactams and some β-lactamase inhib- For HI, susceptibility to most β-lactams is usually predicted itors, we were extremely hesitant to de-escalate. Although HI by susceptibility to ampicillin [2]. Ampicillin resistance often infections have increased 50% in some US locations over the occurs via β-lactamases production or altered penicillin- last decade [3], and atypical presentations such as pyogenic binding proteins (PBPs). Strains with altered PBPs are referred infections of the genitourinary system have emerged [4], to as β-lactamase-negative, ampicillin resistant (BLNAR), but descriptions of type E strains using comparative genomics, and AST agencies debate what constitutes a BLNAR strain and the dilemmas HI can present to clinicians and nonreference whether BLNAR strains should also be considered resistant laboratories, remain scarce. to amoxicillin/clavulanate, ampicillin/sulbactam, cefaclor, Although matrix-assisted laser desorption ionization cefetamet, cefonicid, cefprozil, cefuroxime, loracarbef, and time-of-flight (MALDI-ToF) has simplified the identifica- piperacillin/tazobactam despite apparent in vitro susceptibility tion of HI, AST remains complicated [2]. Most hospital lab- to these agents [2, 5].

oratories do not provide AST results on individual isolates Of the 2 main β-lactamase-encoding genes in HI, blaTEM

or antibiograms for HI due to its fastidious nature and the and blaROB-1, the former is far more prevalent, with only

specialized testing media required. In addition, variation of approximately 10% of strains worldwide harboring blaROB-1 [1, inoculum concentration may lead to falsely resistant results 2]. Both genes are plasmid-mediated and encode class A ser- with some β-lactams, particularly for β-lactamase-producing ine enzymes that are typically inhibited by clavulanate and strains such as the one in this report [5]. Furthermore, no tazobactam [1]. ROB-1 degrades cefprozil but not the oxy- interpretative breakpoints exist for many relevant antibiotics. imino-cephalosporins, ceftriaxone, and cefotaxime. Cefaclor

In fact, one of the major AST agencies is only now establish- exposure may select for blaROB-1-carrying strains, because

ing breakpoints for piperacillin-tazobactam. The other major approximately 70% of cefaclor-resistant strains harbor blaROB-1.

AST agency states that “results of susceptibility testing using blaROB-1 is more prevalent in the United States and Mexico, breakpoints provided for oral β-lactams, macrolides, and where cefaclor use is relatively high [1, 2]. The above suggests ketolide agents may not be useful for the management of indi- that piperacillin-tazobactam, ampicillin-sulbactam, or cef- vidual patients” [2, 5]. Even with advances such as MALDI- triaxone are reasonable empiric choices; for BLNAR strains, ToF and WGS, susceptibility testing and preliminary results cefepime should be considered [2]. still can vex clinical decision making. Clinical laboratories CONCLUSIONS continue to struggle generating timely and actionable AST reports, due to regulatory and technical barriers [6, 7]. In Finally, this report demonstrates the ongoing need for further addition, although WGS has become the “standard-of-care” investigations of bacterial virulence correlates and mechanisms for epidemiology, evidence for using WGS-inferred AST to [9, 10]. Toward that end, we make the isolate and its WGS avail- guide clinical decision making is lacking [8]. able to other researchers.

2 • OFID • ID CASES Acknowledgments 4. Howard-Anderson J, Satola SW, Collins MH. Breech at the border: an atypical Disclaimer. The views expressed in the manuscript are solely those of case of invasive Haemophilus influenzae in a patient on a novel immunotherapeu- tic. Open Forum Infect Dis 2018; 5. doi: 10.1093/ofid/ofy146. the authors and are not to be construed as official or representing those of 5. Clinical and Laboratory Standards Institute. Performance Standards for the Department of Defense. Antimicrobial Susceptibility Testing. 28th ed. CLSI supplement M100. Wayne, Potential conflicts of interest. All authors: No reported conflicts of PA; Clinical and Laboratory Standards Institute; 2018. interest. All authors have submitted the ICMJE Form for Disclosure of 6. Humphries RM, Hindler JA. emerging resistance, new antimicrobial agents … but Potential Conflicts of Interest. no tests! the challenge of antimicrobial susceptibility testing in the current US regulatory landscape. Clin Infect Dis 2016; 63:83–8. 7. Labreche MJ, Graber CJ, Nguyen HM. recent updates on the role of pharmacoki- References netics-pharmacodynamics in antimicrobial susceptibility testing as applied to 1. Galán JC, Morosini MI, Baquero MR, et al. Haemophilus influenzae bla(ROB-1) clinical practice. Clin Infect Dis 2015; 61:1446–52. mutations in hypermutagenic deltaampC Escherichia coli conferring resistance to 8. Ellington MJ, Ekelund O, Aarestrup FM, et al. The role of whole genome sequenc- cefotaxime and beta-lactamase inhibitors and increased susceptibility to cefaclor. ing in antimicrobial susceptibility testing of bacteria: report from the EUCAST Antimicrob Agents Chemother 2003; 47:2551–7. Subcommittee. Clin Microbiol Infect 2017; 23:2–22. 2. Tristram S, Jacobs MR, Appelbaum PC. Antimicrobial resistance in Haemophilus 9. Jones CL, Clancy M, Honnold C, et al. Fatal outbreak of an emerging clone of influenzae. Clin Microbiol Rev 2007; 20:368–89. extensively drug-resistant Acinetobacter baumannii with enhanced virulence. 3. New York State Department of Health. Communicable diseases in New York Clin Infect Dis 2015; 61:145–54. State: cases reported in 2016. Available at: https://www.health.ny.gov/statistics/ 10. Hauser AR, Mecsas J, Moir DT. Beyond antibiotics: new therapeutic approaches Downloaded from https://academic.oup.com/ofid/article/5/12/ofy302/5173656 by guest on 01 October 2021 diseases/communicable/2016/docs/select.pdf. Accessed 15 September 2018. for bacterial infections. Clin Infect Dis 2016; 63:89–95.

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