Evaluation of in-vitro susceptibility of ß-lactam-resistant Gram-negative bacilli to ceftazidime-avibactam and ceftolozane-tazobactam from clinical samples of a general hospital in southern Brazil

ABSTRACT

Background:

The spread of carbapenemase- and extended-spectrum β-lactamase (ESBL)-producing gram-negative bacilli (GNB) represent a global public health threat that limits therapeutic options for hospitalized patients. This study aimed to evaluate the in-vitro susceptibility of β-lactam-resistant GNB to ceftazidime-avibactam (C/A) and ceftolozane-tazobactam (C/T), and investigate the molecular determinants of resistance.

Methods:

Overall, 101 clinical isolates of Enterobacterales and Pseudomonas aeruginosa collected from a general hospital in Brazil were analyzed. Susceptibility to the antimicrobial agents was evaluated using an automated method, and the minimum inhibitory concentrations (MIC50/90) of C/A and C/T were determined using Etest^®. The β-lactamase-encoding genes were investigated using polymerase chain reaction.

Results:

High susceptibility to C/A and C/T was observed among ESBL-producing Enterobacterales (100% and 97.3% for CLSI and 83.8% for BRCAST, respectively) and carbapenem-resistant P. aeruginosa (92.3% and 87.2%, respectively). Carbapenemase-producing Klebsiella pneumoniae exhibited high resistance to C/T (80%- CLSI or 100%- BRCAST) but high susceptibility to C/A (93.4%). All carbapenem-resistant K. pneumoniae isolates were susceptible to C/A, whereas only one isolate was susceptible to C/T. Both antimicrobials were inactive against metallo-β-lactamase-producing K. pneumoniae isolates. Resistance genes were concomitantly identified in 44 (44.9%) isolates, with bla _CTX-M and bla _SHV being the most common.

Conclusions:

C/A and C/T were active against microorganisms with β-lactam-resistant phenotypes, except when resistance was mediated by metallo-β-lactamases. Most C/A- and C/T-resistant isolates concomitantly carried two or more β-lactamase-encoding genes (62.5% and 77.4%, respectively).

Keywords:
Antimicrobial resistance; Gram-negative bacilli; Ceftazidime-avibactam; Ceftolozane-tazobactam; In vitro activity; Genetic marker

INTRODUCTION

Significant clinical and economic impacts are often reported because of bacterial resistance, since long hospital stays and the empirical use of different antimicrobial agents increase healthcare costs, as well as morbidity, and mortality rates¹. The rapid spread of carbapenemase- and extended-spectrum β-lactamase (ESBL)-producing gram-negative bacilli (GNB) represents an important threat to global public health^2,3 and has limited the use of broad-spectrum cephalosporins and carbapenems in hospitalized patients^1,4.

In 2017, the World Health Organization (WHO) published a list of potentially critical multidrug-resistant microorganisms with global priority for the research and development of new antimicrobials, including carbapenem-resistant Pseudomonas aeruginosa and Enterobacterales resistant to carbapenems and third-generation cephalosporins⁵. A few antimicrobial agents have been developed in recent years to combat infections caused by multidrug-resistant GNB^6,7.

Ceftazidime-avibactam and ceftolozane-tazobactam were approved by the Food and Drug Administration (FDA) and the Brazilian Health Regulatory Agency (ANVISA) for the treatment of complicated intra-abdominal and urinary infections^8,9. Ceftazidime-avibactam exerts in-vitro activity against clinical ESBL-producing isolates, including Ambler classes A (serine carbapenemases [KPC]), C (cephalosporinase-AmpC), and some class D enzymes (oxacillinases), but not metallo-β-lactamases (MβL)^9,10. With the addition of avibactam, a β-lactamase inhibitor, ceftazidime tends to expand its activity against resistant strains⁶. Ceftolozane-tazobactam, which is currently approved for the treatment of hospital-acquired and mechanical ventilation-associated bacterial pneumonia¹¹, is a combination of a fifth-generation cephalosporin and a known β-lactamase inhibitor. These agents together exert broad-spectrum activity against gram-negative bacteria, especially multidrug-resistant P. aeruginosa^12-15.

Although recently approved for clinical use and despite its proven efficacy against GNB, resistance to ceftazidime-avibactam and ceftolozane-tazobactam has been reported in several countries¹⁶. In this context, the present study evaluating the in-vitro activity of these antimicrobial agents, as well as genotypic resistance markers, is important for optimizing their use and will also contribute to the understanding of the current epidemiological scenario.

METHODS

Study characterization and selection of clinical isolates

This descriptive study focused on the phenotypic and molecular investigation of P. aeruginosa and Enterobacterales resistant to at least one carbapenem antibiotic or ESBL-producing antibiotic. The isolates were obtained sequentially from microbiological cultures of clinical samples collected from a general hospital in southern Brazil from January 2018. The clinical samples were subjected to routine procedures in the microbiology laboratory of the hospital for the identification of each microorganism, using the automated Microscan Walkaway Plus system (Beckman Coulter, USA) as well as Gram staining.

Phenotypic determination of antimicrobial susceptibility

The antimicrobial susceptibility profile was evaluated using the Kirby-Bauer disk diffusion method and the automated Microscan Walkaway Plus system (Beckman Coulter, USA) to determine the minimum inhibitory concentration (MIC) of each antimicrobial agent. Additionally, the MICs of ceftazidime-avibactam and ceftolozane-tazobactam were defined by a quantitative method using standardized Etest^® strips that contained an exponential concentration gradient. The concentration range used for both antimicrobials was 0.016/4-256/4 mg/L and the results were interpreted using the parameters of the Clinical and Laboratory Standards Institute (CLSI) and of the Brazilian Committee on Antimicrobial Susceptibility Testing (BRCAST).

The isolates were classified as ESBL producers based on the observation of a reduction in the inhibition halos for broad-spectrum β-lactams in the antimicrobial susceptibility test and double-disk synergy test. Isolates were classified as resistant to carbapenems (CR) when resistance to meropenem, ertapenem, or imipenem was identified. The phenotypic detection of carbapenemases was performed using the enzymatic blocking method described in ANVISA Technical Note No. 01/2013¹⁷, which provides prevention and control measures for infections caused by multidrug-resistant Enterobacterales.

Extraction of bacterial DNA and investigation of target genes

Bacterial DNA was extracted from Müller-Hinton agar cultures using heat shock, as previously described¹⁸. To confirm the suitability of the extracted DNA for subsequent genotype analysis, the 16S rRNA gene was identified by the polymerase chain reaction (PCR)¹⁹.

The presence of the target genes was also investigated using PCR. All reactions were carried out in a final volume of 50 μL, using 50-500 ng of extracted DNA. The PCR-amplified products were subjected to electrophoresis on 1% agarose gel and compared with a standard.

The bla _SHV and bla _CTX-M genes were investigated in isolates with positive phenotypic tests for the presence of ESBL, using specific primers. The thermocycling conditions consisted of an initial denaturation step at 94 ^oC for 3 min, followed by 35 cycles of denaturation, annealing, and extension (1 min at 72 ^oC) for each gene, and a final extension at 72 °C for 10 min.

To investigate the carbapenemase-encoding bla _OXA-48-like, bla _NDM-1, bla _KPC, bla _SPM-1, bla _VIM, and bla _IMP genes, isolates showing phenotypic resistance to carbapenems were subjected to PCR consisting of an initial denaturation at 94 ^oC for 3 min, followed by specific thermocycling conditions specific for each target gene. Reference strains were used to confirm the effectiveness of the target gene detection methods.

Statistical analysis

The samples were obtained using convenience sampling. Data were analyzed using descriptive statistics, with calculation of absolute and relative frequencies. Categorical variables are expressed as absolute numbers and percentages.

RESULTS

Overall, 101 bacterial isolates were included in the study: 39 (38.6%) carbapenem-resistant P. aeruginosa, 37 (36.6%) ESBL-producing Enterobacterales, 15 (14.8%) Klebsiella pneumoniae with a positive phenotypic test for KPC, four (4.0%) K. pneumoniae with a positive phenotypic test for MβL, three (3.0%) carbapenem-resistant isolates of the CESP group (consisting of Citrobacter freundii, Enterobacter spp., Serratia spp., Providencia spp., Morganella morganii, and Hafnia alvei), and three (3.0%) carbapenem-resistant K. pneumoniae.

The isolates were collected from urine samples (31.7%; n=32), rectal swabs (16.8%; n=17), wound discharge (15.8%; n=16), bronchoalveolar lavage (11.9%; n=12), and other less common sites (23.8%; n=24). Regarding the distribution of isolates among hospital units, 53.5% (n=54) were from in-patient units, 20.8% (n=21) from the intensive care unit (ICU), 19.8% (n=20) from the emergency department, and 5.9% (n=6) were isolated at the surgical center and from out-patient units. Thirty-seven (36.6%) of the 101 isolates were obtained from surveillance cultures.

In-vitro activity of ceftolozane-tazobactam

The in- vitro activity of ceftolozane-tazobactam against each group of microorganisms selected in this study is shown in Table 1. The ESBL-producing Enterobacterales and CR P. aeruginosa isolates showed high susceptibility. A high resistance rate was observed in the KPC-producing K. pneumoniae isolates. Two CR K. pneumoniae isolates were resistant. All CR isolates of the CESP group and MβL-producing K. pneumoniae were resistant to ceftolozane-tazobactam.

TABLE 1:
In vitro activity of ceftolozane-tazobactam.

	MIC frequency (%)												MIC interpretation (%)						MIC (mg/L)
Group of microorganisms (N)													CLSI			BRCAST
	<1	1	2	3	4	6	8	12	24	32	48	>256	S	I	R	S	I	R	MIC 50	MIC 90	Range
Pseudomonas aeruginosa - CR (39)	15.4	46.2	56.4	66.7	87.2	92.3	94.9			97.4		100	87.2	7.7	5.1	87.2		12.8	2	6	0.38 - >256
Enterobacterales - ESBL (37)	67.6	83.8	97.3									100	97.3		2.7	83.8		16.2	<1	2	0.125 - >256
Klebsiella pneumoniae - KPC (15)			13.3		20.0		26.7	33.3	53.3	60.0	86.7	100	13.3	6.6	80.0			100	24	>256	2,0 - >256
Klebsiella pneumoniae - MβL (4)												100			100			100	>256	>256	>256 - >256
Klebsiella pneumoniae - CR (3)	33.3								66.7		100		33.3		66.6	33.3		66.6	24	48	0.50 - 48
CESP group - CR (3)							33.3					100			100			100	>256	>256	8 - >256

• MIC: minimum inhibitory concentration; S: susceptible; I: intermediate; R: resistant; MIC50 and MIC90 (mg/L): concentrations that inhibit 50% and 90% of the bacterial isolates, respectively. CLSI: Clinical and Laboratory Standards Institute; BRCAST: Brazilian Committee on Antimicrobial Susceptibility Testing. CR: resistance to at least one carbapenem; ESBL: extended-spectrum β-lactamase; KPC: Klebsiella pneumoniae carbapenemase; MβL: metallo-β-lactamase.

In-vitro activity of ceftazidime-avibactam

Table 2 shows the in-vitro activity of ceftazidime-avibactam against each group of microorganisms selected in this study. All ESBL-producing Enterobacterales isolates were susceptible to ceftazidime-avibactam, showing the lowest MIC values compared with the other groups of microorganisms tested. A high susceptibility rate was observed for CR P. aeruginosa.

TABLE 2:
In vitro activity of ceftazidime-avibactam.

	MIC frequency (%)										MIC interpretation (%)			MIC (mg/L)
Group of microorganisms (N)											CLSI and BRCAST
	<1	1	2	3	4	6	8	12	24	>256	S	I	R	MIC 50	MIC 90	Range
Pseudomonas aeruginosa - CR (39)	2.6	33.3	43.6	69.2	76.9	89.7	92.3	94.9	97.4	100	92.3		7.7	3	8	0.50 - >256
Enterobacterales - ESBL (37)	89.2	97.3		100							100			<1	1	0.125 - 3
Klebsiella pneumoniae - KPC (15)	26.7	86.7	93.3							100	93.3		6.6	1	2	0.38 - >256
Klebsiella pneumoniae - MβL (4)										100			100	>256	>256	>256 - >256
Klebsiella pneumoniae - CR (3)	33.3		66.7		100						100			2	4	0.75 - 4
CESP group - CR (3)		33.3			66.7			100			66.7		33.3	4	12	1 - 12

• MIC: minimum inhibitory concentration; S: susceptible; I: intermediate; R: resistant; MIC50 and MIC90 (mg/L): concentrations that inhibit 50% and 90% of the bacterial isolates, respectively. CLSI: Clinical and Laboratory Standards Institute; BRCAST: Brazilian Committee on Antimicrobial Susceptibility Testing. CR: resistance to at least one carbapenem; ESBL: extended-spectrum β-lactamase; KPC: Klebsiella pneumoniae carbapenemase; MβL: metallo-β-lactamase.

The resistance rate of KPC-producing K. pneumoniae was low. All CR K. pneumoniae isolates were susceptible, whereas the MβL-producing K. pneumoniae isolates were resistant. Two bacterial isolates from the CESP group (E. cloacae and S. marcescens) were susceptible, and one was resistant to ceftazidime-avibactam.

Phenotypic antimicrobial susceptibility

Figure 1 summarizes the comparison of ceftazidime-avibactam and ceftolozane-tazobactam susceptibility profiles with the other antimicrobials tested in the different groups of microorganisms studied according to the CLSI breakpoints.

FIGURE 1:
Susceptibility to ceftazidime-avibactam and ceftolozane-tazobactam compared to the other antimicrobials tested in the study.

Genotypic resistance markers

The 16S rRNA gene was amplified in most of the isolates studied (97%, 98/101). The percentage of isolates positive for resistance genes was high (78.6%). Table 3 shows the distribution of the bacterial isolates according to the investigated genotypic resistance markers. All the tested isolates were negative for bla _SPM-1, bla _OXA-48-like, and bla _IMP.

TABLE 3:
Distribution of bacterial isolates according to genotypic resistance markers.

Phenotypic resistance	Species (N)	β-Lactamase genes	Isolates (n)	Isolates (%)
ESBL	Escherichia coli (27)	bla CTX-M	26	96.3
		bla SHV	17	63
	Klebsiella pneumoniae (7)	bla CTX-M	7	100
		bla SHV	6	85.7
	Proteus mirabilis (2)	bla CTX-M	2	100
	Klebsiella ozaenae (1)	bla SHV	1	100
		bla CTX-M	1	100
KPC	Klebsiella pneumoniae (15)	bla KPC	15	100
		bla SHV	14	93.3
		bla CTX-M	12	80
		bla NDM-1	1	6.7
		bla VIM	1	6.7
CR	Pseudomonas aeruginosa (36)	bla CTX-M	14	38.9
		bla SHV	5	13.9
		bla KPC	2	5.6
		bla VIM	1	2.8
	Klebsiella pneumoniae (3)	bla CTX-M	3	100
		bla SHV	3	100
	Klebsiella pneumoniae (3)	bla NDM-1	1	33.3
	Enterobacter cloacae (2)	bla CTX-M	1	50
	Serratia marcescens (1)	bla KPC	1	100
MβL	Klebsiella pneumoniae (4)	bla SHV	4	100
		bla NDM-1	3	75

• ESBL: extended-spectrum β-lactamase; KPC: Klebsiella pneumoniae carbapenemase; CR: resistance to at least one carbapenem; MβL: metallo-β-lactamase.

Coexistence of resistance genes was observed in 44 (44.9%) isolates. The most prevalent combinations were bla _KPC+bla _CTX-M+bla _SHV in KPC-producing K. pneumoniae, and bla _CTX-M+bla _SHV in ESBL-producing Escherichia coli. Most isolates with phenotypic resistance to ceftazidime-avibactam and ceftolozane-tazobactam concomitantly carried two or more β-lactamase-encoding genes (Table 4). The bla _CTX-M, bla _SHV, and bla _KPC were most frequently detected in isolates resistant to ceftolozane-tazobactam, whereas bla _SHV, bla _CTX-M, and bla _NDM-1 were most frequently detected in isolates resistant to ceftazidime-avibactam.

TABLE 4:
Presence of β-lactamase-encoding genes and phenotypic susceptibility to ceftazidime-avibactam (C/A) and ceftolozane-tazobactam (C/T) in the isolates studied.

Phenotypic resistance	Species	Isolates (n)	β-Lactamase genes	Phenotype
				C/A	C/T
ESBL	Escherichia coli	15	bla CTX-M , bla SHV	S	S
		10	bla CTX-M	S	S
		1	bla CTX-M , bla SHV	S	R
		1	bla SHV	S	S
	Klebsiella pneumoniae	5	bla CTX-M	S	S
		1	bla CTX-M , bla SHV	S	R
		1	bla CTX-M	S	R
	Proteus mirabilis	2	bla CTX-M	S	R
	Klebsiella ozaenae	1	bla CTX-M , bla SHV	S	R
KPC	Klebsiella pneumoniae	9	bla KPC , bla CTX-M , bla SHV	S	R
		2	bla KPC , bla SHV	S	R
		1	bla KPC , bla CTX-M , bla SHV , bla NDM-1	S	R
		1	bla KPC, bla CTX-M , bla SHV , bla VIM	S	R
		1	bla KPC , bla CTX-M	S	R
		1	bla KPC , bla SHV	R	R
CR	Pseudomonas aeruginosa	7	bla CTX-M	S	S
		2	bla CTX-M , bla SHV	S	S
		1	bla KPC , bla CTX-M	S	S
		1	bla KPC , bla CTX-M , bla SHV	S	S
		1	bla SHV	S	S
		1	bla VIM	S	S
		1	bla CTX-M	R	S
		1	bla CTX-M	S	R
		1	bla CTX-M , bla SHV	R	R
	Klebsiella pneumoniae	2	bla CTX-M , bla SHV	S	R
		1	bla CTX-M , bla SHV , bla NDM-1	S	S
	Enterobacter cloacae	1	bla CTX-M	R	R
	Serratia marcescens	1	bla KPC	S	R
MβL	Klebsiella pneumoniae	3	bla SHV , bla NDM-1	R	R
		1	bla SHV	R	R

• ESBL: extended-spectrum β-lactamase; KPC: Klebsiella pneumoniae carbapenemase; CR: resistance to at least one carbapenem; MβL: metallo-β-lactamase. C/A: ceftazidime-avibactam; C/T: ceftolozane-tazobactam. R: resistant; S: susceptible.

DISCUSSION

The increasing incidence of bacterial strains isolated from clinical samples that produce carbapenemases, enzymes capable of inactivating carbapenems, and most β-lactams²⁰ represents the greatest challenge of antibiotic therapy in recent years^2,6. Enterobacterales and P. aeruginosa are the main causative agents of severe infections associated with antibiotic resistance resulting from chromosomal mutations and the transfer of plasmid-mediated resistance²¹. Such clinical isolates commonly produce carbapenemases and exhibit multidrug resistance and pan-resistance phenotypes²².

Studies have been conducted in different countries to evaluate in-vitro susceptibility to ceftazidime-avibactam and ceftolozane-tazobactam, and bacterial resistance to these antimicrobial agents has been reported in hospitalized patients with or without previous treatment¹⁶. Furthermore, the combination of resistance mechanisms can significantly increase the MIC of ceftazidime-avibactam and ceftolozane-tazobactam^16,23.

The ability of ceftazidime-avibactam to inhibit KPC-type β-lactamases has attracted global interest. In China, Cui et al. evaluated 347 KPC-producing K. pneumoniae isolates collected from patients without previous treatment with only 12 (3.5%) isolates showing reduced susceptibility to ceftazidime-avibactam²⁴. In Brazil, Rossi et al. found that among 30 selected K. pneumoniae isolates that were not susceptible to meropenem and positive for bla _KPC, only one (3.3%) was resistant to ceftazidime combined with avibactam⁹. Similarly, in our study, the presence of bla _KPC did not influence ceftazidime-avibactam susceptibility, and the resistance rate observed (6.6%; 1/15) was consistent with the global surveillance results of carbapenem-resistant and bla _KPC-carrying K. pneumoniae¹⁰.

Jonge et al. characterized the in vitro activity of ceftazidime-avibactam against 961 meropenem-non-susceptible Enterobacterales isolates from Europe, Asia, Latin America, and the Middle East using a global antimicrobial resistance surveillance program. The authors evaluated 145 MβL-producing isolates and detected a ceftazidime-avibactam resistance rate of 96.6%¹⁰. Similarly, all MβL-producing K. pneumoniae isolates in this study were resistant to ceftazidime-avibactam. Thus, ceftazidime-avibactam is a potent agent against carbapenem-resistant Enterobacterales, except for isolates in which resistance is mediated by MβL.

According to international reports, the resistance rates of P. aeruginosa to ceftazidime-avibactam are higher than those reported for Enterobacterales, ranging from 2.9 to 18%, whereas these rates can reach 50% in isolates resistant to carbapenems¹⁶. Although this study investigated carbapenem-resistant P. aeruginosa isolates, the rate of ceftazidime-avibactam resistance was low (7.7%; 3/39). This might be related to the absence of carbapenemase-encoding genes in most of the isolates investigated, suggesting that the detected phenotypic resistance to carbapenems is associated with other pseudomonal resistance mechanisms not analyzed here/in this study.

Studies have reported that bacteremia caused by ESBL-producing Enterobacterales is associated with higher rates of treatment failure and patient mortality when compared to bacteremia caused by non ESBL-producing strains^1,25. Various authors have emphasized that ESBL-producing Enterobacterales strains are not associated with resistance to ceftazidime-avibactam^{6,7,10,15,25,26}, which was also demonstrated in our study.

López-Calleja et al. analyzed the multidrug-resistant and extensively drug-resistant non-MβL-producing P. aeruginosa isolates collected in Spain and reported 92.2% susceptibility to ceftolozane-tazobactam, which was the second most active antimicrobial agent after colistin²⁷; this was also observed in our study (87.2%). In particular, we did not identify bla _NDM-1 or bla _IMP genes in carbapenem-resistant P. aeruginosa isolates, and the bla _VIM gene detected in only one isolate was not associated with the ceftolozane-tazobactam resistance phenotype. In contrast, Teo et al. highlighted the importance of geographic variation in antimicrobial activity. The authors reported much lower susceptibility rates of P. aeruginosa to ceftolozane-tazobactam (37.9%), which was associated with the presence of MβL, compatible with local molecular epidemiology²⁸.

Tuon et al. evaluated 673 GNB isolates collected from different Brazilian centers and found rates of in-vitro susceptibility to ceftolozane-tazobactam ranging from 40.4% to 94.9%. The susceptibility rate of K. pneumoniae to ceftolozane-tazobactam was low (40.4%) because of the high incidence of KPC-type carbapenemases in Brazil, an enzyme that catalyzes the hydrolysis of ceftolozane²⁹. In our study, the susceptibility rate of KPC-producing K. pneumoniae to ceftolozane-tazobactam was even lower (13.3%). This finding might be explained by the identification of bla _KPC gene in all isolates tested and the concomitant presence of ESBL-encoding genes. Additionally, two isolates carrying more than one carbapenemase- and ESBL-encoding gene (bla _KPC +bla _CTX-M +bla _SHV +bla _NDM-1 and bla _KPC+bla _CTX-M +bla _SHV +bla _VIM) were identified in association with ceftolozane-tazobactam resistance phenotypes. Regarding MβL-producing K. pneumoniae, all isolates were resistant to ceftolozane-tazobactam and most of them carried bla _NDM-1, suggesting that this agent should be used with caution in empirical therapies.

In contrast, we found high rates of in-vitro ceftolozane-tazobactam susceptibility among ESBL-producing Enterobacterales. This finding in consistent with a study that evaluated 21,952 Enterobacterales isolates from 51 countries and found that ceftolozane-tazobactam inhibited 82.4% of ESBL-producing isolates¹⁵.

This study had some limitations. The number of isolates evaluated was relatively small, and the study was conducted at a single hospital. However, the study used clinical isolates selected in recent years to better reflect the current epidemiological scenario. Therefore, we recommend multicenter studies using a phenotypic and genotypic approach and a greater number of multidrug-resistant isolates for better understanding of the local molecular epidemiology and for the detection of resistance to ceftazidime-avibactam and ceftolozane-tazobactam in different regions of Brazil.

In conclusion, we found high susceptibility rates to ceftazidime-avibactam and ceftolozane-tazobactam among ESBL-producing Enterobacterales and carbapenem-resistant Pseudomonas aeruginosa. In contrast, carbapenemase-producing Klebsiella pneumoniae exhibited high resistance to ceftolozane-tazobactam but high susceptibility to ceftazidime-avibactam. Our results obtained in-vitro confirmed that ceftazidime-avibactam and ceftolozane-tazobactam were active against microorganisms with β-lactam resistance phenotypes, except when resistance was mediated by metallo-β-lactamases. Additionally, most ceftazidime-avibactam- and ceftolozane-tazobactam-resistant isolates concomitantly carried two or more β-lactamase-encoding genes.

ACKNOWLEDGMENTS

The authors thank the laboratory staffs at Universidade da Região de Joinville (Univille) and Hospital Dona Helena, in Joinville.

REFERENCES

• ¹
  Friedman ND, Temkin E, Carmeli Y. The negative impact of antibiotic resistance. Clin Microbiol Infect. 2016;22(5):416-22.
• ²
  Sekar R, Srivani S, Kalyanaraman N, Thenmozhi P, Amudhan M, Lallitha S, et al. New Delhi Metallo-β-lactamase and other mechanisms of carbapenemases among Enterobacteriaceae in rural South India. J Glob Antimicrob Resist. 2019;18:207-14.
• ³
  Wu C, Wang Y, Shi X, Wang S, Ren H, Shen Z, et al. Rapid rise of the ESBL and mcr-1 genes in Escherichia coli of chicken origin in China, 2008-2014. Emerg Microbes Infect. 2018;7:1-10.
• ⁴
  Melo LC, Oresco C, Leigue L, Netto HM, Melville PA, Benites NR, et al. Prevalence and molecular features of ESBL/pAmpC-producing Enterobacteriaceae in healthy and diseased companion animals in Brazil. Vet Microbiol. 2018;221:59-66.
• ⁵
  World Health Organization. Global priority list of antibiotic-resistant bacteria to guide research, discovery, and development of new antibiotics. WHO,2017.
• ⁶
  Alatoom A, Elsayed H, Lawlor K, AbdelWareth L, El-Lababidi, Cardona L, et al. Comparison of antimicrobial activity between ceftolozane - tazobactam and ceftazidime - avibactam against multidrug-resistant isolates of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa Int J Infect Dis. 2017;62:39-43.
• ⁷
  Tuon FF, Rocha JL, Formigoni-Pinto MR. Pharmacological aspects and spectrum of action of ceftazidime-avibactam: a systematic review. Infection. 2017;46(2):165-81.
• ⁸
  BRASIL. Agência Nacional de Vigilância Sanitária. Parecer público de avaliação de medicamento-aprovação, 2018.
• ⁹
  Rossi F, Cury AP, Franco MRG, Testa R, Nichols WW. The in vitro activity of ceftazidime-avibactam against 417 Gram-negative bacilli collected in 2014 and 2015 at a teaching hospital in São Paulo, Brazil. Braz J Infect Dis. 2017;21(5):569-73.
• ¹⁰
  Jonge BLM, Karlowsky JA, Kazmierczak KM, Biedenbach DJ, Sahm DF, Nichols WW. In vitro susceptibility to ceftazidime-avibactam of carbapenem-nonsusceptible Enterobacteriaceae isolates collected during the INFORM global surveillance study (2012 to 2014). Antimicrob Agents Chemother. 2016;60(5):3163-9.
• ¹¹
  Garcia-Fernandez S, García-Castilho M, Melo-Cristino J, Pinto MF, Gonçalves E, Alves V, et al. In vitro activity of ceftolozane-tazobactam against Enterobacterales and Pseudomonas aeruginosa causing urinary, intra-abdominal and lower respiratory tract infections in intensive care units in Portugal: the STEP multicentre study. Int J Antimicrob Agents. 2019;55(3):1058-87.
• ¹²
  Carvalhães CG, Castanheira M, Sader HS, Flamm RK, Shortridge D. Antimicrobial activity of ceftolozane-tazobactam tested against gram-negative contemporary (2015-2017) isolates from hospitalized patients with pneumonia in US medical centers. Diagn Microbiol and Infect Dis. 2019;94(1):92-102.
• ¹³
  Gherardi G, Linardos G, Pompilio A, Fiscarelli E, Di Bonaventura D. Evaluation of in vitro activity of ceftolozane-tazobactam compared to other antimicrobial agents against Pseudomonas aeruginosa isolates from cystic fibrosis patients. Diagn Microbiol and Infect Dis . 2019;94(3):297-303.
• ¹⁴
  Gómez-Junyent J, Benavent E, Sierra Y, El Haj C, Soldevila L, Torrejón B, et al. Efficacy of ceftolozane/tazobactam, alone and in combination with colistin, against multidrug-resistant Pseudomonas aeruginosa in an in vitro biofilm pharmacodynamic model. Int J Antimicrob Agents . 2019;53(5):612-9.
• ¹⁵
  Karlowsky JA, Kazmiercza KM, Young K, Motyl MR, Sahm DF. In vitro activity of ceftolozane/tazobactam against phenotypically defined extended-spectrum β-lactamase (ESBL)-positive isolates of Escherichia coli and Klebsiella pneumoniae isolated from hospitalized patients (SMART 2016). Diagn Microbiol and Infect Dis . 2019;96(4):11492-5.
• ¹⁶
  Wang Y, Wang J, Wang R, Cai Y. Resistance to ceftazidime-avibactam and underlying mechanisms. J Glob Antimicrob Resist . 2020;22:18-27.
• ¹⁷
  ANVISA. Nota Técnica n 01/2013: Medidas de prevenção e controle de infecções por enterobactérias multirresistentes, 2013.
• ¹⁸
  Kobs VC, Augustini FJ, Bobrowicz TA, Ferreira LE, Deglmann RC, Westphal GA. The role of the genetic elements bla oxa and ISAba1 in the Acinetobacter calcoaceticus-Acinetobacter baumannii complex in carbapenem resistance in the hospital setting. Rev Soc Bras Med Trop. 2016;49(4):433-40.
• ¹⁹
  Eden PA, Schmidt TM, Blakemore RP, Pace NR. Phylogenetic analysis of aquaspirillum magnetotacticum using polymerase chain reaction-amplified 16S rRNA-specific DNA. Inter Journal Sys Bacteriol. 1991;41;324-5.
• ²⁰
  Karam G, Chastre J, Wilcox MH, Vincent JL. Antibiotic strategies in the era of multidrug resistance. Crit Care. 2016;20(1):136.
• ²¹
  Van Duin D, Doi Y. The global epidemiology of carbapenemase-producing Enterobacteriaceae Virulence. 2016;8(4):460-9.
• ²²
  Magiorakos AP, Srinivasan A, Carey RB, Carmeli Y, Falagas ME, Giske CG, et al. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: An international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect . 2012;18(3):268-81.
• ²³
  Schillaci D, Spano V, Parrino B, Carbone A, Montalbano A, Barraja P, et al. Pharmaceutical approaches to target antibiotic resistance mechanisms. J Med Chem. 2017;60(20):8268-97.
• ²⁴
  Cui X, Shan B, Zhang X, Qu F, Jia W, Huang B, et al. Reduced ceftazidime-avibactam susceptibility in KPC-producing Klebsiella pneumoniae from patients without ceftazidime-avibactam use history - A Multicenter Study in China. Front Microbiol. 2020;11:1365.
• ²⁵
  Sah BS, Aryal M, Bhargava D, Siddique A. Drug resistance pattern of bacterial pathogens of Enterobacteriaceae family. TUJM. 2017;4:15-22.
• ²⁶
  Castanheira M, Doyle TB, Mendes RE, Sader HS. Comparative activities of ceftazidime-avibactam and ceftolozane-tazobactam against Enterobacteriaceae isolates producing extended-spectrum β - lactamases from U.S. hospitals. Antimicrob Agents Chemother . 2019;63(7):e00160-19.
• ²⁷
  Lopéz-Calleja AI, Morales EM, Medina RN, Esgueva MF, Pareja JS, Gárcia-Lechuz JM, et al. Antimicrobial activity of ceftolozane-tazobactam against multidrug-resistant and extensively drugresistant Pseudomonas aeruginosa clinical isolates from a Spanish hospital. Rev Esp Quimioter. 2019;32(1):68-72.
• ²⁸
  Qi-Min Teo J, Lim JC, Tang CY, Lee SJY, Tan SH, Sim JHC, et al. Ceftolozane/tazobactam resistance and mechanisms in carbapenem-nonsusceptible Pseudomonas aeruginosa mSphere. 2021;6(1):1026-20.
• ²⁹
  Tuon FF, Cieslinski J, Rodrigues SS, Serra FB, De Paula MDN. Evaluation of in vitro activity of ceftolozane-tazobactam against recent clinical bacterial isolates from Brazil - the EM200 study. Braz J Infect Dis . 2020;24(2):96-103.

• Financial Support: This study was supported by the Foundation for Research and Innovation Support of the State of Santa Catarina (FAPESC; Grant: 2019TR159) and the Research Support Fund of the University of the Region of Joinville (FAP/Univille).

Publication Dates

• Publication in this collection
  23 Jan 2023
• Date of issue
  2023

History

• Received
  12 July 2022
• Accepted
  11 Oct 2022