Oct. 2016

THE JAPANESE JOURNAL OF ANTIBIOTICS

69―5343（ 43 ）〈Case Report〉

A case of pediatric patient with acute enteritis dueto CTX-M-15 extended-spectrum
β-lactamase-producing Salmonella Blockley
SATORU KUTSUNA1), SHOTA YONETANI2), KOJI ARAKI2)
and HIDEMASA IZUMIYA3)
1)

Department of Pediatrics, Kyorin University School of Medicine
Laboratory of Medicine, Kyorin University School of Medicine
3)
Department of Bacteriology I, National Institute of Infectious Diseases
2)(Received for publication June 20, 2016)

This clinical case report concerns a pediatric patient with acute enteritis caused bymulti-drug resistant Salmonella enterica serovar Blockley (Salmonella Blockley). A
3-year-old boy presented to our emergency room with a 5-day history of fever,abdominal pain, and bloody diarrhea. Stool culture tested positive for a Salmonella
species, while the blood culture was negative. The patient was successfully treatedwith an oral antibiotic regimen of fosfomycin. The stool isolate was found to beresistant to multiple drugs, including cefpodoxime, cefotaxime, ceftazidime, andaztreonam, and was conﬁrmed to be a CTX-M-15 extended-spectrum β-lactamase(ESBL)-producing strain of Salmonella Blockley. This is the ﬁrst report of apediatric patient in Japan with acute enteritis caused by a CTX-M-15 ESBLproducing strain of Salmonella Blockley.

Introduction
Salmonella enterica serovar Blockley (Salmonella Blockley) is a strain of non-typhoidal
Salmonella (NTS) that is isolated occasionally in infectious enteritis in Japan1). Compared toother Enterobacteriaceae including Escherichia coli and Klebsiella pneumoniae, extendedspectrum β-lactamase (ESBL) production was previously rare in Salmonella enterica strains.
However, the recent reports suggested that these strains show an increasing trend in the world2).
But, the case of human infection due to ESBL-producing NTS is rare in Japan. We report here theﬁrst pediatric case with enteritis due to CTX-M-15 ESBL-producing Salmonella Blockley inJapan.

344（ 44 ）THE JAPANESE JOURNAL OF ANTIBIOTICS

69―5

Oct. 2016

Case presentation
In August 2015, a 3-year-old boy presented to the emergency room at Kyorin University
Hospital (Tokyo, Japan) with a 5-day history of fever, abdominal pain, and bloody diarrhea. His
medical history was unremarkable, with no recent history of any prolonged illness, hospitalization, previous antibiotics use, or similar illness in the family or preschool. His life history was unremarkable, with no history of eating eggs or raw foods or traveling abroad, but he did have adog. His parents also had never been abroad ever. Initial vital signs showed a temperature of38°C, while other vital signs were normal. Physical examination revealed abdominal pain aroundthe umbilicus. Other systemic examinations were normal. Laboratory data showed a white blood
cell count of 7,700/mm3 (neutrophils: 51.5%), platelet count of 233,000/mm3, hemoglobin 11.3 g/dl, and C-reactive protein 1.86 mg/dl. Liver and renal function tests showed no abnormalities. Infectious enteritis was suspected, and stool and blood cultures were performed. The stool culture
tested positive for a Salmonella species, but the blood culture was negative. The stool isolate wasresistant to ampicillin, cefazolin, cefpodoxime, cefotaxime, ceftazidime, cefepime, and aztreonam, but susceptible to meropenem, ampicillin-sulbactam, piperacillin-tazobactam, trimethoprimsulfamethoxazole, ciproﬂoxacin, levoﬂoxacin, minocycline, and fosfomycin. Given its resistanceto third generation cephalosporins and monobactams, we suspected an ESBL-producing
Salmonella species. It was serotyped as Salmonella Blockley using anti-O, -H sera, and thepresence of a blaCTX-M β-lactamase gene was conﬁrmed through polymerase chain reaction(PCR) with CTX-M universal primers F(5′-TTTGCGATGTGCAGTACCAGTAA-3′) andR(5′-CGATATCGTTGGTGGTGCCATA-3′), as described previously EDELSTEIN et al.3); the isolate
tested positive for blaCTX-M. Next, we conﬁrmed the presence of a blaCTX-M-15 β-lactamase geneusing PCR, with primers F(5′-ATGGTTAAAAAATCACTGCG-3′) and R(5′-GGTGACGATTTTAGCCGCCGA-3′) (NG 048935; 101-120, 664-644), the ampliﬁed PCR product was sequenced
to ﬁnd that it completely matched with corresponding part of the known blaCTX-M-15 sequence.
Three different PCR assays run at the National Institute of Infectious Diseases to test for blaTEM,blaCMY, and blaCTX-M-15, detected only blaCTX-M-15. The patient was treated immediately with anoral antibiotics regimen of fosfomycin (90 mg/kg/day) for 5 days, after which his condition improved. A follow-up stool culture was negative for Salmonella Blockley. Source of infection
could not be identiﬁed.

Discussion
NTS represents one of the principal pathogens implicated in food-borne enteritis worldwide.
All cases of Salmonella food poisoning of outbreak in Japan are required to be reported to theMinistry of Health, Labour and Welfare. Incidences of Salmonella food poisoning has shown aOct. 2016

THE JAPANESE JOURNAL OF ANTIBIOTICS

69―5345（ 45 ）clear reduction since 2000 in Japan, such that the yearly incidence has remained under 50 for thepast few years. On the other hand, incidences of infectious enteritis by NTS with individual caseare unclear. Cases for which NTS was isolated at our hospital have increased since 2007, as follows: 11 ceses in 2007–2009 (5 children, 6 adults), 18 cases in 2010–2012 (4 children, 14 adults),
and 31 cases in 2013–2015 (13 children, 18 adults). We surmise that infectious enteritis by NTS
without Salmonella food poisoning may have increased due to the diversiﬁed dietary culture andincreased overseas travel. ESBL-producing NTS has not been isolated in our hospital. Although
the case of human infection due to ESBL-producing NTS is rare in Japan, the three cases were reported. CTX-M-14 ESBL-producing Salmonella enteritidis was ﬁrst isolated from a pediatric patient with enteritis in 2005, CTX-M-2 ESBL-producing Salmonella Heidelberg was isolated froma pediatric patient with enteritis in 2013, and CTX-M-55 ESBL-producing Salmonella enteritidis
was isolated from an adult patient with liver abscess in 20144〜6).
Several organisms producing clavulanic acid-inhibited Ambler class A ESBL have been reported, mostly in Enterobacteriaceae, in addition to those producing TEM- and SHV-type ESBL.
Among these enzymes, the CTX-M-type β-lactamases are plasmid-mediated ESBL and confer ahigh level of resistance to cefotaxime, ceftriaxone, aztreonam and have only marginal effects on
the minimal inhibitory concentration of ceftazidime7). The CTX-M-15 ESBL were identiﬁed inEnterobacteriaceae isolates in India in 2001, and demonstrated signiﬁcant hydrolytic activity
against ceftazidime, in contrast to the majority of CTX-M enzymes8). The initial reports of CTXM-15-producing NTS came from France and Senegal in 20049). Clinical isolation of CTXM-15-producing NTS was reported at our country in 201410). CTX-M-type ESBL-producing
Enterobacteriaceae are important nosocomical infectious agents raising considerable concern
in the public health community. While no marked increases in CTX-M ESBL-producing NTS
have been reported in Japan, detection rates should be monitored closely.
The most common clinical illness caused by NTS inclucing Salmonella Blockley is acute enteritis. Symptoms of acute enteritis by NTS usually resolve within a week in healthy children
without antibiotic therapy, and thus antibiotics are not routinely indicated11). However, transient
bacteremia during NTS gastroenteritis is believed to occur in 1–5% of patients. In these instances, NTS can enter the bloodstream and become uniquely capable of metastasizing and causing a focal suppurative infection of almost any origin12). Children with bacteremia or extraintestinal focal Salmonella infection should receive antimicrobial therapy, for which ﬂuoroquinolones
and third generation cephalosporins would be the antibiotics of choice. In a report of fetal acutepyogenic meningitis caused by ESBL-producing Salmonella typhimurium, the patient was empirically started on an intravenous antibiotic regimen of cefotaxime and gentamicin, but died fromacute pyogenic meningitis13). As ﬂuoroquinolones are not indicated in pediatric patients, thirdgeneration cephalosporins are recommended instead. Because there is a case of enteritis due toESBL-producing Salmonella species, it is necessary to pay attention to the selection of antimicro-346（ 46 ）THE JAPANESE JOURNAL OF ANTIBIOTICS

69―5Oct. 2016bial agents.
We are the ﬁrst to report on the identiﬁcation of a CTX-M-15 ESBL-producing Salmonella
Blockley isolate associated with pediatric enteritis in Japan. While clear increases in ESBL-producing NTS have not been noted in Japan, close attention should be paid to the selection of antimicrobial agents for treatment, and to potential resistance against antimicrobial agents by NTS.
Conﬂict of interest
None.

References
1) MATSUSHITA, S.; M. KAWAMURA, M. TAKAHASHI, et al.: Serovar-distribution and drug-resistance ofSalmonella strains isolated from domestic and imported cases during 1995–1999 in Tokyo. Jpn.
Assoc. Inf. Dis. 75: 116〜123, 2001
2) BATCHELOR, M.; K. HOPKINS, E. J. THRELFALL, et al.: bla(CTX-M) genes in clinical Salmonella isolates recovered from humans in England and Wales from 1992 to 2003. Antimicrob. Agents Chemother. 49: 1319〜1322, 2005
3) EDELSTEIN, M.; M. PIMKIN, I. PALAGIN, et al.: Prevalence and molecular epidemiology of CTX-M
extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in Russian hospitals. Antimicrob. Agents Chemother. 47: 3724〜3732, 2003
4) IZUMIYA, H.; K. MORI, M. HIGASHIDE, et al.: Identiﬁcation of CTX-M-14 beta-lactamase in a
Salmonella enterica serovar enteritidis isolate from Japan. Antimicrob. Agents Chemother. 49:
2568〜2570, 2005
5) UENO, M.: First report of extended-spectrum-beta-lactamase-producing Salmonella enterica serovar Heidelberg isolates in Japan. J. Pediatr. Inf. Dis. Immunol. 25: 23〜27, 20136) IMOTO, A.; Y. OOI, S. EDOGAWA, et al.: Liver abscess caused by CTX-M-55-type extended-spectrum beta-lactamase(ESBL)-producing Salmonella enteritidis. Intern. Med. 53: 1699〜1703, 2014
7) TZOUVELEKIS, L. S.; E. TZELEPI, P. T. TASSIOS, et al.: CTX-M-type beta-lactamases: an emerging
group of extended-spectrum enzymes. Int. J. Antimicrob. Agents 14: 137〜142, 2000
8) KARIM, A.; L. POIREL, S. NAGARAJAN, et al.: Plasmid-mediated extended-spectrum β-lactamase(CTX-M-3 like) from India and gene association with insertion sequence ISEcp1. FEMS Microbiol. Lett. 201: 237〜241, 2001
9) WEILL, F. X.; J. D. PERRIER-GROS-CLAUDE, M. DEMARTIN, et al.: Characterization of extended-spectrum-beta-lactamase (CTX-M-15)-producing strains of Salmonella enterica isolated in France andSenegal. FEMS Microbiol. Lett. 238: 353〜358, 2004
10) OSAWA, K.; K. SHIGEMURA, R. SHIMIZU, et al.: Antimicrobial resistance in Salmonella strains clinically isolated in Hyogo, Japan (2009–2012). Jpn. J. Infect. Dis. 67: 54〜57, 2014
11) Feigin and Cherryʼs Textbook of Pediatric Infectious Diseases, 6th edition, SAUNDERS, 1567〜1582, 200912) Nelson textbook of pediatrics. 17th edition, RICHARD, E. B. & N. K. ROBERT, SAUNDERS, 912〜916, 2004
13) MENEZES, G. A.; B. N. HARISH & S. C. PARIJA: A case of fatal pyogenic meningitis in a neonate
caused by extended-spectrum beta-lactamase producing Salmonella group B. Jpn. J. Infect. Dis.
61: 234〜235, 2008