Academia Journal of Microbiology Research 4(5): 078-085, May 2016 DOI: 10.15413/ajmr.2016.0113 ISSN: 2315-7771 ©2016 Academia Publishing

Research Paper

Current Patterns and Predictive Trends of Multidrug Resistant Salmonella Typhi Isolated from Wastewater

Accepted 15th July, 2016 ABSTRACT Enteric fever has persistence of great impact in public health. It is caused by Salmonella enteric that is seldom detected in wastewaters due to the treatment processes. The aim of this study is to evaluate the recent state of antibiotics susceptibility of Salmonella typhi with special concern to multidrug resistance strains and predict the emergence of new resistant patterns. Predictions of resistance emergence were done using logistic regression and forecasting linear equations. A total of 12 S. typhi isolated strain were recovered from 128 samples of wastewater; they resisted antibiotics except Ciprofloxacin. Current patterns of ciprofloxacin breakpoints interpretations were in susceptible ranges by disc diffusion (S ≥ 20 mm); minimum inhibitory concentration was recorded as (I =16 µg/ml) and minimum bactericidal concentration= (R≥32 µg/ml). The probability of an isolate to develop resistance was plotted for MBCs, the rate of resistance solved by (y = 0.0235x - 0.0411). The predictive patterns of resistance were spontaneously solved using the exponential trend (y = n ex) for each isolate at 16 and 32 µg/ml, respectively of ciprofloxacin in certain period and the high values of coefficient R² > 0.5 indicated the rates of bacteria resistance incidence. Key words: Antibiotics/ ciprofloxacin/ Salmonella typhi/ prediction/ resistance.

INTRODUCTION Typhoid fever is a major cause of morbidity and mortality in developing countries (Crump et al., 2004). The causative organism, Salmonella typhi has rapidly gained resistance to antibiotics like ampicillin, chloramphenicol and cotrimoxazole, and also to previously efficacious drugs like ciprofloxacin (Jesudason et al., 1996; Butt et al., 2003). Resistance to the antimicrobial agents such as amoxicillin, trimethoprim-sulfamethoxazole, and chloramphenicol is being increasingly reported among S. typhi isolates; quinolone resistance has been reported from the Indian subcontinent and Southeast Asia. Determining anti-microbial resistance patterns is essential in recommending treatment (Dorian et al., 2001).

Ciprofloxacin is a promising alternative antibiotic for its ability to penetrate into the macrophages and its ability to kill multidrug-resistant strains (Sen et al., 1991; Takkar et al., 1994; Dorian et al., 2001). However, the emergence of ciprofloxacin resistant Salmonella strains has been

reported (Baliga et al., 1999; Nath et al., 2003; Capoor et al., 2007). Because of its broad spectrum, potency and oral efficacy, ciprofloxacin could be useful for oral treatment of systemic infections (Roger et al., 1985). The incidence of multidrug resistant S. typhi was found in India to be as high as 60% and has been a scourge for those afflicted with enteric fever all over the world, while there are many reports noting decline of susceptibility to ciprofloxacin (Sanghavi et al., 1999; Saha et al., 2001; Chaude et al., 2002; Gautam et al., 2002).

Resurgence of resistant Salmonella well-known is increasing in the number of MDR strains against nalidixic acid although; the isolates were sensitive to ciprofloxacin and ceftriaxone (Ackets et al., 2000; Kumar et al., 2002). Therefore, it is necessary for susceptibility pattern of the particular strain isolated from patient to be determined by the sensitivity test in the laboratory (Mackie and McCartney, 1996). Variation in the susceptibility patterns

Ayman A. Elshayeb1*, Abdelazim A. Ahmed1,2, Marmar A. El Siddig1 and Adil A. El Hussien1

1Department of Botany, Faculty of Science, University of Khartoum, Sudan. 2Albaha University, Saudi Arabia. *Corresponding author. E-mail: ayman_elshayeb@yahoo.com. Tel.: +249122974208.

Academia Journal of Microbiology Research; Elshayeb et al. 079 for S. typhi is important to monitor and suitable guidelines for ciprofloxacin treatment given as oral tablets which could be well absorbed from the gastrointestinal tract after oral administration should be provided (Islam et al., 2008).

Routine investigation of ciprofloxacin MICs in patients presented with invasive Salmonella infections should be done (Ray et al., 2006; Parry et al., 2010). However, revealing reduced susceptibility to ciprofloxacin (MICs, 0.125 to 1 µg/ml iter) have emerged and become endemic in South and South-East Asia (Brown et al., 1996; Jesudason et al., 1996; Rahman et al., 2005). Such strains have also been described from other parts of the world (Wain et al., 1997; Threlfall and Ward, 2001). Consequently, there is treatment failure with ciprofloxacin in patients infected with these organisms (Dimitrov et al., 2007). Since isolates with reduced susceptibility to fluoroquinolones may become highly resistant upon sequential accumulation of mutations in topoisomerase genes, their prediction by the use of simpler screening tools implying antibiotic discs is of great value (Hirose et al., 2002; Hooper, 2000). For predicting problems, it is important to establish whether the time-series incorporates any sort of trend, otherwise by definition forecasting would be impossible (Abidi and Goh, 1998). The application of pharmacokinetics and/ or pharmacodynamics (PK/PD) parameters in forecasting the result of an antibiotic therapy in an individual patient undoubtedly requires the knowledge of the rules of pharmacokinetics. It also requires the possibility to monitor the drug concentration in the biological material and to mark the actual MIC value (Szałek et al., 2010). Objectives

This work was conducted to evaluate the recent efficiency of common antibiotics used against S. typhi in Sudan and predict the future trends and fluctuations of ciprofloxacin susceptibility using inexpensive materials and simple statistical methods to support the decision for antimicrobial choice and dosage.

MATERIALS AND METHODS Wastewater samples

Wastewater samples (n=128) were collected from two different sources in Khartoum State, these included; Soba Stabilization Station for wastewater treatment (88 samples) and the wastewater station of Omdurman Military Hospital (40 samples). Samples were collected aseptically, in triplicates according to the standard methods of the (ISO-6579, 2002) in sterile plastic bottles. The samples were immediately transferred to the laboratory for bacteriological analyses.

Isolation of Salmonella typhi

Wastewater samples were treated with buffered peptone water medium (in a 1:10 v/v ratio) and incubated for 12 h. Isolation of Salmonella was performed by adding an aliquot of 1.0 ml from the water sample to 10 ml broth medium for enrichment of each of Rappaport vassiliadis and Tetrathionate and incubated at 41 and 37°C for 12 h respectively. Spreading was made from the each broth medium onto Xylose Lysine Desoxycholate (XLD) and Salmonella-Shiegella (SS) agar media for selective isolation. White colonies with black centers and total black colonies on XLD and SS media were picked and maintained in nutrient agar slants for further studies. Biochemical and serological diagnosis of Salmonella typhi

Various biochemical tests were performed according to the recommendations of ISO-6579, 2002 standards. These tests were in order, growth on Triple sugar iron (TSI) agar and urea agar, Methyl Red (MR) to Vogues Proskauer (VP) and Indole reaction. Serotyping was done using polyvalent O-anti sera A-G and H (flagellar) -anti sera. Antibiotic susceptibility testing

The anti-microbial resistance of the isolated strain was tested against seven anti-microbial agents by the agar diffusion method with Mueller-Hinton agar (Difco) and antibiotic disks (Hi Media) following the guidelines of the Clinical Laboratory Standards Institute (CLSI, 2005). The antibiotics tested were those commonly used for gram negative bacteria; they are in mcg/disc: Tetracycline (TE30mcg), Ofloucin (OF5mcg), Cefroxin (CXM30mcg), Cotrimaxzole (COT25mcg), Amoxyclar (AMC30mcg), Gentamycin (GEN30mcg) and ciprofloxacin (Cip5mcg). The discs were placed on the surface of the agar plates that has been inoculated with test bacteria and incubated overnight at 37ºC. The diameters of inhibition zones were measured and reference tables used to determine if the bacteria are Sensitive (S), Intermediate (I) or Resistant (R) to certain antibiotics. A standard E.coli strain ATCC25922 was also tested for quality control (Sahlstrom et al., 2006).

Determination of ciprofloxacin minimum inhibition concentration (MIC)

A bacterial suspension was made in sterile nutrient broth by colonies from a pure culture and the turbidity adjusted to 0.5 McFarland standards to make a concentration of about 107 CFU/ml. Sensitivity to ciprofloxacin was evaluated by the macro-dilution test according to the criteria stipulated by the (CLSI, 2005) with serial

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Table 1. Interpretation of antibiotics’ susceptibility for Salmonella Typhi.

Samples interpretation

Tetracycline TE30

OfloucinOF5

CefroxinCXM30

CotrimaxzoleCOT25

AmoxyclarAMC30

Gentamycin GEN30

Ciprofloxacin Cip5

S ≤ I= R ≥ S ≤ I= R≥ S ≤ I= R ≥ S ≤ I= R ≥ S ≥ I= R ≥ S ≤ I= R ≥ S≤ I = R ≥ E. coli 0 0 16 0 0 16 0 0 11 23 0 0 0 0 0 30 0 0 20 0 0 Dr11 0 0 0 30 0 0 31 0 0 0 0 0 0 0 0 0 0 0 31 0 0 D14 0 19 0 30 0 0 0 0 15 0 0 0 0 0 0 35 0 0 35 0 0 S1 25 0 0 20 0 0 0 0 15 20 0 0 0 0 0 32 0 0 45 0 0 S2 27 0 0 33 0 0 0 0 0 30 0 0 0 0 10 32 0 0 40 0 0 S3 22 0 0 42 0 0 0 0 13 0 0 0 0 0 0 0 18 0 42 0 0 S4 0 0 8 45 0 0 0 0 11 0 0 0 0 0 0 0 20 0 35 0 0 S5 0 0 7 45 0 0 0 0 0 0 0 0 0 0 0 30 0 0 45 0 0 S6 0 18 0 39 0 0 0 0 12 33 0 0 0 0 11 0 20 0 40 0 0 S7 0 0 11 40 0 0 0 0 15 20 0 0 0 0 0 30 0 0 40 0 0 S8 22 0 0 35 0 0 0 0 0 30 0 0 0 0 0 35 0 0 35 0 0 S9 20 0 0 40 0 0 0 0 0 35 0 0 0 0 12 33 0 0 40 0 0 S10 22 0 0 42 0 0 0 0 11 34 0 0 0 0 0 28 0 0 42 0 0

Ciprofloxacin dilutions of 8, 16, 0.32, 0.064 and 0.128 µg/ml respectively. Results were recorded as minimum inhibitory concentrations (MIC). A standard E. coli strain ATCC25922 was also tested for quality control. Determination of minimum bactericidal concentration (MBC) Following the MICs determination, 100 μl were aspirated from the wells of the microplates that showed growth inhibition and then inoculated on the surface of plates containing Mueller-Hinton agar medium. Plates were incubated overnight and visually examined for bacterial growth. A standard strain E. coli ATCC25922 was also tested for quality control. Probability of ciprofloxacin resistance (%) To determine the thresholds of bacteria resistance to ciprofloxacin, statistical probabilities for MBCs

breakpoints were done by trending normal probability plot. Prediction of ciprofloxacin resistance Time-series prediction (calculated from the current susceptibility pattern) was employed by using simple statistical systems (regression and simple moving average) for the temporal variations in S. typhi sensitivity or resistance towards ciprofloxacin. RESULTS Isolation and identification of S. typhi Bacteria were isolated from all of the 128 collected wastewater samples. Typical Salmonella colonies were recovered from SS and XLD media. Isolates serotyping showed that 9 (75%) had the antigenic formula O:9(D1) for S. typhi, 3 (25%) had the formula Salmonella enteric Paratyphi A 1,2,12 a

[1,5] and S. enteric Paratyphi C1 6,7,[Vi] c 1,5 respectively. Antibiotics susceptibility test Deferent patterns were shown by the 12 S. typhi isolated strain for their response against the seven tested antibiotics (Table 1). It is clear that at least one or more isolate was resistant to four of the tested antibiotics; exceptions were COT25mcg, GEN30mcg and Cip5mcg. However, three isolates (S3, S4 and S6) had intermediate resistance to GEN30mcg. Eight isolates were resistant to CXM30mcg. Minimum inhibitory concentration (MIC): The MIC of ciprofloxacin against the S. typhi isolated strain and the control E. coli strain (Table 2) indicated that two S. typhi namely; Dr11 and S8 were capable of tolerating ciprofloxacin as high as 32 µg/ml, five (S3, S6, S7, S9 and S10) can grow in

Academia Journal of Microbiology Research; Elshayeb et al. 081

Table 2. Ciprofloxacin minimum inhibitory concentration (MIC).

Sample control 8 µg/ml 16

µg/ml 32 µg/ml 0.064 µg/ml 0.128 µg/ml

E. coli + + + + - -

Dr 11 + + + + - -

Dr 14 + + - - - -

S1 + + - - - -

S2 + - - - - -

S3 + + + - - -

S4 + + - - - -

S5 + + - - - -

S6 + + + - - - S7 + + + - - - S8 + + + + - - S9 + + + - - - S10 + + + - - -

Table 3. Ciprofloxacin minimum bactericidal concentration (MBC).

Interpretation Conc. µg/ml E. coli Dr 11 Dr 14 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10

Control 0.000 260 230 250 255 251 258 244 239 246 250 248 257 240

S ≥ 8 14 10 21 7 14 12 17 21 20 40 12 20 28

I= 16 6 9 6 5 4 3 3 5 6 6 7 9 8

R ≤ 32 1 8 3 1 2 1 1 2 2 2 5 6 4

R ≤ 0.064 0 0 0 0 0 0 0 0 0 0 0 0 0

R ≤ 0.128 0 0 0 0 0 0 0 0 0 0 0 0 0

Table 4. Probabilities of ciprofloxacin resistance occurrence.

Interpretation Ciprofloxacin concentration µg/ml Probability of resistance occurrence (%)

Control 0.000 0

S ≥ 8 25

I= 16 42

R ≤ 32 58

R ≤ 0.064 75

R ≤ 0.128 92

16 µg/ml and four isolates (Dr14, S1, S4 and S5) showed no growth at concentrations higher than 8 µg/ml while isolate S2 could not tolerate any of the tested ciprofloxacin concentrations. Therefore, any isolated strain that showed resistance to ciprofloxacin higher than 16 µg/ml was considered as resistant isolate. Minimum bactericidal concentration (MBC) The MBC breakpoints of the 12 S. typhi and the control E. coli can tolerate 32 µg/ml ciprofloxacin indicating an emergence of resistance against this antibiotic that should have more attention. All isolated strain resisted ciprofloxacin concentration as high as 32 mg/ml. Meanwhile, the increasing of the drug concentration led to a decrease in the MBCs colonies numbers (Table 3).

Probabilities of ciprofloxacin resistance occurrence among (MBCs) Statistical analysis between antibiotics concentrations (µg/ml) and MBCs breakpoints was done by MBCs trending plot for the probability of resistance occurrence. The probability of an isolate to develop resistance increases with the increase in ciprofloxacin concentration (Table 4). The plotted graph showed the percentage probability of MBCs to resist ciprofloxacin concentrations and their empirical observations were solved by: (y = nx –b) (1) The Spearman coefficient of determination was calculated R² = 0.8381 and it corresponds significantly to the rate of resistance occurrence by (y = 0.0235x - 0.0411).

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Table 5. Prediction of ciprofloxacin resistance interpreted of 16 µg/ml.

Incubation E. coli Dr 11 Dr 14 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10

Actual 12 h 6 9 6 5 4 3 3 5 6 6 7 9 8 day 1 7 9 5 6 4 3 5 6 6 6 7 9 9 day 2 8 8 7 5 5 4 6 6 7 7 8 10 11 day 3 8 9 7 6 5 4 7 7 7 7 9 12 12 day 4 9 10 8 7 5 5 6 7 7 7 9 12 12 day 5 9 11 8 7 6 5 6 8 8 8 11 13 13 day 6 9 12 8 8 7 6 8 9 8 8 13 14 13 day7 9 13 8 8 7 6 8 9 9 8 16 15 14

Table 6. Prediction of ciprofloxacin resistance interpreted of 32 ug/L.

Incubation E. coli Dr 11 Dr 14 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 Actual 12 h 1 8 3 1 2 1 1 2 2 2 5 6 4 day 1 1 9 6 2 2 2 1 2 3 2 5 6 5 day 2 1 10 7 4 2 2 1 2 3 3 6 7 5 day 3 2 10 8 6 3 2 1 3 3 3 6 7 6 day 4 2 10 9 7 4 2 2 3 3 3 7 8 7 day 5 3 10 10 8 6 3 2 3 4 3 7 8 7 day 6 4 11 10 9 7 4 3 3 4 3 8 9 7 day7 5 12 11 10 8 6 3 4 5 4 8 10 8

Figure 1. Predicition of ciprofloxacin MBC resistance’s trends at 16 µg/ml.

Prediction of ciprofloxacin susceptibility trends The increasing numbers of MBCs equal to the probability of more cells grown with ciprofloxacin and develop resistance during 12 h of incubation period (Tables 5 and 6). It is clear that Tables 5 and 6 showed the numbers of resisted colonies have daily increased with no specific pattern.

Minimum bactericidal concentration’s predication of E. coli ATCC25922 resistance was given by (y = 6.2391e0.0513x) and the coefficient (R² = 0.7). S. typhi, (Dr11, Dr14, S1... S10) were obtained by the exponential trend (y = n ex) and

the coefficient R² > 0 <1 are approximately alike. The bacteria resistance after long term of incubation

period (7 days) with ciprofloxacin was predicted by: (y = n ex) (2) Where; (n) is the numbers of colonies (MBCs) and (ex) is the exponent positive integer which corresponds to increasing probabilities of resistance incident at certain time. The predictive coefficient R² value for each isolate at 16 and 32 µg/ml of ciprofloxacin are shown in (Figures 1 and 2). The predictive patterns of all isolated strain

y = 6.239e0.051x

R² = 0.720

0

2

4

6

8

10

12

14

16

18

Actual 12 hr

day 1 day 2 day 3 day 4 day 5 day 6 day7

MB

C B

reak

po

ints

at

16

ug/

l

Time series

E.coli

Dr 11

Dr 14

S1

S2

S3

S4

S5

S6

S7

S8

S9

S10

Expon. (E.coli)

Actual 12 h

MB

C B

rea

kp

oin

t at

16

µg/L

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Figure 2. Predicition of ciprofloxacin MBC resistance’s trends at 32 µg/ml.

Table 7. Predictive patterns of resistance in Salmonella typhi.

Sample 16 µg/ml

32 µg/ml Exponential trend coefficient Exponential trend coefficient

E. coli ATCC25922 y = 6.2391e0.0513x R² = 0.7208 y = 0.5978e0.2636x R² = 0.9455 Dr11 y = 7.621e0.0604x R² = 0.7886 y = 8.0752e0.0458x R² = 0.9347 Dr14 y = 5.2505e0.0676x R² = 0.7903 y = 3.7532e0.1528x R² = 0.7738 S1 y = 4.5725e0.0717x R² = 0.9591 y = 1.153e0.3069x R² = 0.8695 S2 y = 3.2991e0.0977x R² = 0.9339 y = 1.1018e0.2501x R² = 0.9066 S3 y = 2.7596e0.1016x R² = 0.9254 y = 0.7688e0.2367x R² = 0.9544 S4 y = 3.6258e0.1079x R² = 0.6979 y = 0.7328e0.172x R² = 0.9362 S5 y = 4.8046e0.0834x R² = 0.958 y = 1.5462e0.1135x R² = 0.7652 S6 y = 5.5536e0.0552x R² = 0.8698 y = 2.0479e0.1038x R² = 0.8484 S7 y = 5.7606e0.0459x R² = 0.884 y = 1.8061e0.0911x R² = 0.9553 S8 y = 5.7004e0.1168x R² = 0.9397 y = 4.5789e0.0745x R² = 0.9477 S9 y = 8.0663e0.0787x R² = 0.9797 y = 5.2388e0.0759x R² = 0.886 S10 y = 7.7298e0.0796x R² = 0.9237 y = 3.9538e0.0955x R² = 0.9566

showed increase in the exponential trends of ciprofloxacin concentrations of 16 and 32 µg/ml; this correlates to the increasing probabilities of resistance occurrence (Table 7). The table also showed high values of coefficient R² > 0.5 and this indicated how well the data fit the statistical model. DISCUSSION Stabilization stations are installed to eliminate pathogenic bacteria from the effluent; Salmonella spp. isolated from wastewater of Soba and Omdurman Hospital originated from infected humans and survived during the treatment at station ponds. It also highlights the risk of spreading resistant Salmonella strains from sewage sludge to the environment (Sahlstrom et al., 2006). The biochemical and serotyping investigations was confirmed as S. enterica subsp. Enteri caserovar typhi and Paratyphi (ISO 6579,

2002). Fourth generation Fluoroquinolone antibiotics are

commonly used to treat a variety of illnesses such as respiratory and urinary tract infections. These medicines include ciprofloxacin, gemifloxacin, levofloxacin, moxifloxacin, norfloxacin and ofloxacin are active against a wide range of aerobic Gram-positive and Gram-negative organisms. Ciprofloxacin susceptibility was tested and the proposed breakpoints calculated with a standard E. coli ATCC25922 as reference (CLSI, 2005). Interpretation of antibiotics’ susceptibility for S. typhi showed sensitive pattern of ciprofloxacin to all isolated strain (Table 1) and resistance to some others. This is in line with the results of Madhulika et al. (2004) and Islam et al. (2008) who reported similar results of anti-microbial susceptibility pattern of Salmonella paratyphi that showed sensitivity to Ciprofloxacin up to (50%), (Madhulika et al., 2004). Interpretation of MICs ciprofloxacin indicated breakpoints for macro-dilution and showed 99% of the isolated strain

y = 0.597e0.263x

R² = 0.945

0

2

4

6

8

10

12

14

Actual 12 hr day 1 day 2 day 3 day 4 day 5 day 6 day7

MB

C B

reak

po

ints

at

32

ug/

l

Time series

E.coli

Dr 11

Dr 14

S1

S2

S3

S4

S5

S6Actual 12 h

MB

C B

rea

kp

oin

t at

32

µg/L

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Figure 3. Ciprofloxacin normal probability plot.

were categorized as susceptible by determining MICs using (CLSI, 2015) breakpoints (16 µg/ml ) (Table 2). The result agreed with Al-Gamy et al. (2012) and is explained by Sushila et al. (2014); when the isolated strain become more tolerant to ciprofloxacin they showed higher MICs without new mutation after 8 g/L. Meanwhile, the accumulation of mutations under continuous ciprofloxacin pressure led to clinical failure (Sushila et al., 2014). The ciprofloxacin minimum bactericidal concentration (MBCs) showed similar pattern of susceptibility for most S. typhi isolated strain (Table 3). Several studies have used the MBC as an indication of biocide resistance (Rose et al., 2009; Kawamura-Sato et al., 2010; Knapp et al., 2013). Others reported that the sensitivity pattern of causative organisms must be studied and determined before instituting appropriate therapy to prevent further emergence of drug resistance (Bronzwaer, 2003; Sharma et al., 2006; Al-Agamy et al., 2012). The probability of ciprofloxacin resistance may occur during the course, and it can be plotted as a linear equation, where the coefficient of isolated strain is found to be resistant (Figure 3). Bronzwaer (2003) reported the use of relevant antibiotics (beta-lactam antibiotics and macrolides) and the log odds of resistance are modeled through linear regression; a strong linear and statistically significant relationship is demonstrated (Bronzwaer, 2003). The prediction of resistance models demonstrated that the scale of the impact was relatively more influential for ciprofloxacin (Figures 1 and 2).

Sharma et al. (2006) identified the MIC of an anti-microbial agent is a value that has been used to determine breakpoints that predict the probability of clinical success and detect resistant populations, or both (Bronzwaer, 2003). Moreover, probability trends in the MIC or its MBC distribution above the threshold may not be observed

whereas the distribution to the left of the threshold is not expected to change over time. When such changes in the resistant isolated strain are expected, then, the ordinal or quantitative scale of distribution trends needs to be considered (Sharma et al., 2006). The emergence of ciprofloxacin resistance pattern could be predicted (in vitro) by changing the values from actual to forecast in the time-line of the experiment (Figures 1 and 2). In vivo (CLSI, 2005) guidelines confirmed that some anti-microbial agents are associated with the emergence of resistance during prolonged therapy. Therefore, isolated strains that are initially susceptible may become resistant within three to four days after the initiation of therapy (Sahlstrom et al., 2006). However, the past record of rapid emergence of resistance to newly introduced antibiotics indicates that even new families of antibiotics will have a short life expectancy. Earlier information of an antibiotic efficiency in treating a bacterial organism can potentially play a major role in controlling an infectious outbreak. In a typical disease control scenario, the strategy is to eradicate the culprit bacteria before it has the chance to spread and infect a larger population. Conclusion The present patterns of ciprofloxacin susceptibility are in normal ranges. This study assesses the prediction of multi-drug resistance among S. typhi isolates by applying low cost materials and simple statistical methods suitable for the most commonly used antibiotics as empirical therapy. Therefore, bacterial surveillance systems should be implemented to provide data on the etiology and prevailing anti-microbial drug resistance patterns of community-acquired agents causing bacteremia.

y = 0.023x - 0.041R² = 0.838

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0% 25% 42% 58% 75% 92%

Co

nc

mg/

l

Probability of resistance %

Co

nce

ntr

ati

on

(m

g/L

)

Probability of resistance (%)

58 0 25 42 92 75

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Cite this article as: Elshayeb AA, Ahmed AA, Siddig MAE, Hussien AAE (2016). Current Patterns and Predictive Trends of Multidrug Resistant Salmonella Typhi Isolated from Wastewater. Acad. J. Microbiol. Res. 4(5): 078-085. Submit your manuscript at http://www.academiapublishing.org/ajmr