Prevalence and Characterization of Extended-Spectrum Cephalosporin-Resistant NontyphoidalSalmonellaIsolates in Adults in Saint Petersburg, Russia (2002–2005)

Abstract

We studied the prevalence of resistance to extended-spectrum cephalosporins (ESC) among 1,078 Salmonella enterica isolates collected from adults admitted to Botkin Hospital, St. Petersburg, Russia, for gastroenteritis between 2002 and 2005. Only two ESC-resistant isolates were detected, giving a low percentage of strains resistant to ESC (0.2%). One multidrug-resistant (MDR) isolate of the Virchow serotype produced a CTXM-3 extended-spectrum beta-lactamase (ESBL). The bla(CTX-M-3) gene was located downstream from an ISEcp1 element, on an 80-kb conjugative plasmid. The Virchow isolate possessed a class 1 integron with a 2.2-kb gene cassette (dhfrXII-orfF-aadA2). The second ESC-resistant isolate belonged to serotype Newport, was also MDR and produced a CMY-2 cephamycinase. This CMY-2-producing isolate (also called Newport MDR-AmpC) possessed a class 1 integron with a 1-kb gene cassette including a new variant of the aadA gene, aadA24. A large plasmid (>125 kb) was involved in transfer of the bla(CMY-2) gene. The ESC-resistant S. enterica isolates detected in this study were different from those (S. enterica serotype Typhimurium DT193 producing CTXM-4 or CTX-M-5 ESBLs) involved in several nosocomial outbreaks between 1994 and 2003 in Russia. This is the first description of both CTX-M-3 ESBL-producing S. enterica and Newport MDR-AmpC in Russia.

Ceftriaxone-ResistantSalmonella entericaSerotype Newport, France

“…No bla TEM genes were detected. Three isolates with additional resistance to aminoglycosides contained a class 1 integron with the 1-kb gene cassette aadA24 (known to encode resistance to strep- tomycin and spectinomycin) (11). The chloramphenicol/ fl orfenicol resistance gene fl oR was detected in all but 1 CMY-2-producing Newport isolate.…”

16S rRNA Methyltransferases: An Emerging Resistance Mechanism Against Aminoglycosides in Salmonella

“…armA was also identified on a plasmid identical, or very similar to pCTX-M3 in a single isolate of S. enterica serovar Virchow among 1,078 non-typhoidal Salmonella isolates from patients hospitalized with gastroenteritis in Saint Petersburg, Russia between (Egorova et al, 2007. The armA gene associated with Tn1548 was also identified in one isolate of S. enterica serovar Stanley submitted in 1999 among a collection of 18,261 nontyphoidal Salmonella isolated between 1996-2006 at the Centers for Disease Control and Prevention, USA (Folster et al, 2009).…”

Salmonella enterica Serotype Gambia with CTX-M-3 and armA Resistance Markers: Nosocomial Infections with a Fatal Outcome

“…A type (e.g., type XGAM-1) was assigned to each PFGE pattern differing by one or more additional bands Ͼ50 kb in size. PCR assays to detect bla TEM , bla CTX-M , and bla SHV were performed on isolates 05-5446 and 05-5447, as described previously (7,8). PCR products were subjected to direct sequencing with an Applied Biosystems sequencer (model ABI 377), and nucleotide sequences were analyzed with the BLAST and ClustalW programs.…”